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What is the strong inelastic material found in a human tendon?

Tendon | Article about tendon by The Free Dictionary Tendon | Article about tendon by The Free Dictionary http://encyclopedia2.thefreedictionary.com/tendon Related to tendon: Achilles tendon tendon, tough cord composed of closely packed white fibers of connective tissue that serves to attach muscles to internal structures such as bones or other muscles. Sometimes when the muscle involved is thin and wide, the tendon is not a cord but a thin sheet known as an aponeurosis. The purpose of the tendon in attaching muscle to bone is to enable the power of the muscle to transfer over a distance. For example, when one wants to move a finger, specific muscles in the forearm contract and pull on ligaments that in turn pull the finger bones to produce the desired action. Tendon A cord connecting a muscle to another structure, often a bone. A tendon is a passive material, lengthening when the tension increases and shortening when it decreases. This characteristic contrasts with the active behavior of muscle. Away from its muscle, a tendon is a compact cord. At the muscle, it spreads into thin sheets called aponeuroses, which lie over and sometimes within the muscle belly. The large surface area of the aponeuroses allows the attachment of muscle fibers with a total cross-sectional area that is typically 50 times that of the tendon. See Muscle Tendons are living tissues that contain cells. In adult tendons, the cells occupy only a very small proportion of the volume and have a negligible effect on the mechanical properties. Like other connective tissues, tendon depends on the protein collagen for its strength and rigidity. The arrangement of the long, thin collagenous fibers is essentially longitudinal, but incorporates a characteristic waviness known as crimp. The fibers lie within a matrix of aqueous gel. Thus, tendon is a fiber-reinforced composite (like fiberglass), but its collagen is much less stiff than the glass and its matrix is very much less stiff than the resin. See Collagen The function of tendons is to transmit force. They allow the force from the muscle to be applied in a restricted region. For example, the main muscles of the fingers are in the forearm, with tendons to the fingertips. If the hand had to accommodate these muscles, it would be too plump to be functional. Tendon extension can also be significant in the movement of a joint. For example, the tendon which flexes a human thumb joint is about 7 in. (170 mm) long. The maximum force from its muscle stretches this tendon about 0.1 in. (2.9 mm), which corresponds to rotation of the joint through an angle of about 21°. See Joint (anatomy) Some tendons save energy by acting as springs. In humans, the Achilles tendon reduces the energy needed for running by about 35%. This tendon is stretched during the first half of each step, storing energy which is then returned during takeoff. This elastic energy transfer involves little energy loss, whereas the equivalent work done by muscles would require metabolic energy in both stages. See Connective tissue , Muscular system Tendon   a cord consisting of connective tissue; a tendon attaches a muscle to a bone and causes a contracting muscle to move. Tendons are composed of thick, strong, inelastic collagen fibers. The fibers are continuous with the muscle fibers at one end and are interwoven into the periosteum at the other end. Tendons vary in shape; those attached to long muscles are cylindrical, and those attached to transverse muscles are flattened and are termed aponeuroses. The centrum tendineum and galea aponeurotica are distinctive in shape. Some tendons, for example, those of the long flexor muscles of the fingers and toes, are surrounded by a synovial membrane that releases a fluid enabling the tendons to slide easily during motion. Tendon function may be impaired by inflammation or injury. Diseases of the tendons and synovial bursae are treated conservatively. Surgery is indicated when tendons are ruptured as a result of injury. tendon

What material forms the hard outermost layer of a human tooth?

Teeth - Anatomy Pictures and Information Home > Skeletal System > Bones of the Head and Neck > Teeth Teeth The teeth are a group of hard organs found in the oral cavity. We use teeth to masticate (or chew) food into tiny pieces. They also provide shape to the mouth and face and are important components in producing speech. A tooth can be divided into two main parts: the crown and root. Found above the gum line, the crown is the enlarged region of the tooth involved in chewing. Like an actual crown, the crown of a tooth has many ridges on its top surface to aid in the chewing of food. Below the gum line is the region of the tooth called the root, which anchors the tooth into a bony socket known as an alveolus.... Move up/down/left/right: Click compass arrows Rotate image: Click and drag in any direction, anywhere in the frame Identify objects: Click on them in the image 2D Interactive 3D Rotate & Zoom Change Anatomical System Teeth: Dental Plaque and Periodontal Disease Full Teeth Description [Continued from above] . . . Roots are tapered structures resembling the roots of plants, and each tooth may have between one to three roots. The exterior surface of the root is covered in a bone-like mixture of calcium and collagen fibers known as cementum. Cementum provides grip for the periodontal ligaments that anchor the root to the surrounding alveolus. Each tooth is an organ consisting of three layers: the pulp, dentin, and enamel. The pulp of the tooth is a vascular region of soft connective tissues in the middle of the tooth. Tiny blood vessels and nerve fibers enter the pulp through small holes in the tip of the roots to support the hard outer structures. Stem cells known as odontoblasts form the dentin of the tooth at the edge of the pulp. Surrounding the pulp is the dentin, a tough, mineralized layer of tissue. Dentin is much harder than the pulp due to the presence of collagen fibers and hydroxylapatite, a calcium phosphate mineral that is one of the strongest materials found in nature. The structure of the dentin layer is very porous, allowing nutrients and materials produced in the pulp to spread through the tooth. The enamel – the white, outer layer of the crown – forms an extremely hard, nonporous cap over the dentin. Enamel is the hardest substance in the body and is made almost exclusively of hydroxylapatite. Teeth are classified into four major groups: incisors, canines, premolars, and molars. Incisors are chisel-shaped teeth found in the front of the mouth and have a flat apical surface for cutting food into smaller bits. Canine teeth, also known as cuspids, are sharply pointed, cone-shaped teeth that are used for ripping tough material like meat. They flank the incisors on both sides. Premolars (bicuspids) and molars are large, flat-surfaced teeth found in the back of the mouth. Peaks and valleys on the flat apical surface of premolars and molars are used for chewing and grinding food into tiny pieces. Babies are born without teeth, but grow a temporary set of twenty deciduous teeth (eight incisors, four canines, and eight molars) between the ages of six months and three years. Baby teeth fill the child’s tiny jaws and allow the child to chew food while larger, stronger adult teeth develop inside the mandible and maxilla bones. At about six years of age the deciduous teeth are slowly shed one at a time and replaced by permanent adult teeth. Adult teeth develop while hidden within the maxilla and mandible after the deciduous teeth have erupted. When an adult tooth erupts, it triggers the roots of the deciduous tooth above it to atrophy. This causes the baby tooth to become loose and eventually fall out. The new permanent tooth slowly pushes up through the gums to replace the baby tooth. Eventually, a total of thirty-two permanent adult teeth form and erupt. The adult teeth are arranged in both the upper and lower jaws from the midline of the mouth as follows: central incisor, lateral incisor, canine (cuspid), first premolar (bicuspid), second premolar, first molar, second molar, and third molar. The first twenty

Snowflakes are symmetrical. How many sides do they have?

Frequently Asked Questions about Snow Crystals    ... Things you always wanted to know about snow crystals ... Why do snow crystals form in such complex and symmetrical shapes?    To see why snowflakes look like they do, consider the life history of a single snow crystal, as shown in the diagram at right.  (Click on the picture for a larger view.)    The story begins up in a cloud, when a minute cloud droplet first freezes into a tiny particle of ice.  As water vapor starts condensing on its surface, the ice particle quickly develops facets , thus becoming a small hexagonal prism .  For a while it keeps this simple faceted shape as it grows.    As the crystal becomes larger, however, branches begin to sprout from the six corners of the hexagon (this is the third stage in the diagram at right).  Since the atmospheric conditions (e. g. temperature and humidity) are nearly constant across the small crystal, the six budding arms all grow out at roughly the same rate.    While it grows, the crystal is blown to and fro inside the clouds, so the temperature it sees changes randomly with time.  But the crystal growth depends strongly on temperature (as is seen in the morphology diagram ).  Thus the six arms of the snow crystal each change their growth with time.  And because all six arms see the same conditions at the same times, they all grow about the same way.  The end result is a complex, branched structure that is also six-fold symmetric.  And note also that since snow crystals all follow slightly different paths through the clouds, individual crystals all tend to look different.    The story is pretty simple, really, nicely encapsulated in the diagram above.  And it's even a bit amazing, when you stop to ponder it -- the whole complex, beautiful, symmetrical structure of a snow crystal simply arises spontaneously, quite literally out of thin air, as it tumbles through the clouds.  What synchronizes the growth of the six arms?    Nothing.  The six arms of a snow crystal all grow independently, as described in the previous section.  But since they grow under the same randomly changing conditions, all six end up with similar shapes.    If you think this is hard to swallow, let me assure you that the vast majority of snow crystals are not very symmetrical.  Don't be fooled by the pictures -- irregular crystals (see the Guide to Snowflakes ) are by far the most common type.  If you don't believe me, just take a look for yourself next time it snows.  Near-perfect, symmetrical snow crystals are fun to look at, but they are not common. Why do snow crystals have six arms?    The six-fold symmetry of a snow crystal ultimately derives from the hexagonal geometry of the ice crystal lattice .  But the lattice has molecular dimensions, so it's not trivial how this nano-scale symmetry is transferred to the structure of a large snow crystal.    The way it works is through faceting .  No long-range forces are necessary to form facets; they appear simply because of how the molecules hook up locally in the lattice (see Crystal Faceting for how this works).  From faceting we get hexagonal prisms , which are large structures with six-fold symmetry.  Eventually arms sprout from the corners of a prism, and six corners means six arms.    Faceting is how the geometry of the water molecule is transferred to the geometry of a large snow crystal. Why is snow white?    No, it's not a white dye.  Snow is made of ice crystals, and up close the individual crystals look clear, like glass.  A large pile of snow crystals looks white for the same reason a pile of crushed glass looks white.  Incident light is partially reflected by an ice surface, again just as it is from a glass surface.  When you have a lo

What name is given to an atomic particle carrying a negative charge?

Discovery of the Electron: J. J. Thomson Elements and Atoms: Chapter 16 Discovery of the Electron: J. J. Thomson Joseph John Thomson (J. J. Thomson, 1856-1940; see photo at the Science Museum, London) is widely recognized as the discoverer of the electron. Thomson was the Cavendish professor of Experimental Physics at Cambridge University and director of its Cavendish Laboratory from 1884 until 1919. For much of his career, Thomson worked on various aspects of the conduction of electricity through gases. In 1897 he reported that "cathode rays" were actually negatively charged particles in motion; he argued that the charged particles weighed much less than the lightest atom and were in fact constituents of atoms [Thomson 1897a, 1897b ]. In 1899, he measured the charge of the particles, and speculated on how they were assembled into atoms [ Thomson 1899 ]. He was awarded the Nobel Prize for physics in 1906 for this work, and in 1908 he was knighted. His Nobel lecture is reproduced below. The case of the electron raises several interesting points about the discovery process. Clearly, the characterization of cathode rays was a process begun long before Thomson's work, and several scientists made important contributions. In what sense, then, can Thomson be said to have discovered the electron? After all, he did not invent the vacuum tube or discover cathode rays. Discovery is often a cumulative process. The credited discoverer makes crucial contributions to be sure, but often after fundamental observations have been made and tools invented by others. Thomson was not the only physicist to measure the charge-to-mass ratio of cathode rays in 1897, nor the first to announce his results. (See Pais 1986.) But Thomson did carry out this measurement and (later) the measurement of the particles's charge, and he recognized its importance as a constituent of ordinary matter. Carriers of negative electricity Nobel Lecture, December 11, 1906; in Nobel Lectures: Physics, 1901-1921 (Amsterdam: Elsevier, 1967), pp. 145-153 Introductory In this lecture I wish to give an account of some investigations which have led to the conclusion that the carriers of negative electricity are bodies, which I have called corpuscles [1] , having a mass very much smaller than that of the atom of any known element, and are of the same character from whatever source the negative electricity may be derived. [2] The first place in which corpuscles were detected was a highly exhausted tube [3] through which an electric discharge was passing. When an electric discharge is sent through a highly exhausted tube, the sides of the tube glow with a vivid green phosphorescence. That this is due to something proceeding in straight lines from the cathode--the electrode where the negative electricity enters the tube--can be shown in the following way (the experiment is one made many years ago by Sir William Crookes [4] ): A Maltese cross made of thin mica is placed between the cathode and the walls of the tube. [5] When the discharge is past, the green phosphorescence no longer extends all over the end of the tube, as it did when the cross was absent. There is now a well-defined cross in the phosphorescence at the end of the tube; the mica cross has thrown a shadow and the shape of the shadow proves that the phosphorescence is due to something travelling from the cathode in straight lines, which is stopped by a thin plate of mica. The green phosphorescence is caused by cathode rays [6] and at one time there was a keen controversy as to the nature of these rays. Two views were prevalent: one, which was chiefly supported by English physicists, was that the rays are negatively electrified bodies shot off from the cathode with great velocity; the other view, which was held by the great majority of German physicists, was that the rays are some kind of ethereal vibration or waves. [7] The arguments in favour of the rays being negatively charged particles are primarily that they are deflected by a magnet in just the same way as moving, negatively electrifie

DNA is found in which part of the cell?

Where is DNA Found? Learn About DNA in Human Cells as well as in Plants, Animals, Bacteria & Outer Space! Human Cells Nucleus DNA can be found inside the nucleus of every cell, apart from red blood cells. It's tightly wound and spread throughout the 46 chromosomes. One set of 23 chromosomes is inherited from each parent. Inside the chromosomes the DNA exists as genes. A gene is a sequence of DNA, that by and large, though there are exceptions, codes for one protein. There is large volume of so-called 'junk DNA' that apparently serves no purpose, although there are bodies of work that are starting to show otherwise.   Mitochondria These are tiny organelles that are the energy factories of the cell. They contain a small amount of DNA that is distinct from nuclear DNA. For the most part mitochondrial DNA is inherited from the mother in sexually reproducing species. slide 2 of 6 Plants and Animals In plants and animals DNA is also found in the cell nucleus . The DNA of all animals is very similar. The major differences are in the number of chromosomes and genes, and the arrangement of base pairs within these genes. slide 3 of 6 Viral DNA A virus is essentially a very simple particle with nucleic acid at its core and a few essential proteins, such as its protein coat. The nucleic acid can be either DNA or RNA, depending on the kind of virus it is. The DNA can also be either single stranded or double stranded. Examples of viruses with a double stranded DNA molecule are; Herpes simplex virus and the small pox virus. Examples of viruses with a single stranded DNA molecule are; Adeno-associated virus and the M13 bacteriophage - it infects bacteria. Viruses do not possess nuclei. slide 4 of 6 Bacterial DNA The DNA is not enclosed inside a nucleus. It's free-floating as it is inside a virus. It's usually a single coil of DNA. In some bacteria there's additional DNA and this is located in structures known as plasmids. The DNA here is not essential to the survival of the bacterium. slide 5 of 6 DNA in Space Well .... every time an astronauts blasts off. Digitized versions of personal DNA sequences will soon be sent up as part of a publicity drive to promote the Archon X $10 million genome sequencing prize. Among those whose DNA will be digitized are physicist and best-selling author Prof Stephen Hawking and the comedian Stephen Colbert. slide 6 of 6

By which name is the drug acetylsalicylic acid better known?

Drug names and classes - National Library of Medicine - PubMed Health Home > Drug names and classes Drug names and classes A drug can have several names. There is usually a generic name for a drug substance plus one or more brand names. You can search for drugs by either their generic or brand names on PubMed Health. You can also search for drug classes. Generic names for drugs are chosen by a variety of official bodies. That means that these names sometimes vary from country to country. For example, the generic name for one common pain medication is acetaminophen in the USA. However in many countries the same drug is called paracetamol. Drug manufacturers choose the brand names of their products. There can be many brands of a particular drug. A brand name is also sometimes called a “proprietary” name. The brand names are usually easier to say and easier to remember. They may be better known than the generic name. Acetaminophen is often called by one of its commonly used brands in the USA: Tylenol. Drug classes A drug also belongs to one or more drug classes. A drug class is a group of drugs that have something in common. They are similar in some way, but they are not identical. Drugs can be in a class with other drugs because: The drugs are related by their chemical structure. Example: Aspirin is a salicylate. Its full chemical name is “acetylsalicylic acid” or ASA. A salicylate is a chemical found in plants, for example, in willow tree bark and the meadowsweet plant. The drugs work in the same way. Example: Aspirin can prevent the formation of blood clots by stopping molecules in the blood called platelets from clumping or aggregating. So it belongs to a drug class called anti-platelets or platelet aggregation inhibitors. The drugs are used for the same purpose. Example: Aspirin is used to reduce fever. Drugs that treat fever are called anti-pyretic drugs or anti-pyretics. Sometimes, we will have a page on a drug class. The drugs listed on those pages are ones for which we have information (not necessarily all of the drugs included in that class).  You can find information about searching for drugs on PubMed Health here . By PubMed Health, 20 August 2015. Share on Facebook

How many legs has an insect?

How many legs does an insect have? | Reference.com How many legs does an insect have? A: Quick Answer An insect has six legs. Insects' legs are jointed, and the movement of these joints is controlled by a combination of partial musculature and passive biomechanical non-muscular structures. Some insects also have a clawlike structure on the last segments of their legs. Full Answer All insects also have three major body regions, which typically consist of a head, a thorax and an abdomen. All insects also have bilateral symmetry. Insects begin their lives as eggs and undergo a metamorphosis before becoming adults. Winged insects have either one pair of wings (such as a housefly or a mosquito) or two pairs of wings (such as a bee or a dragonfly).

Which flower has the same name as a diaphragm in the eye?

Comparing the Human Eye and a Camera The human eye is a wonderful instrument, relying on refraction and lenses to form images. There are many similarities between the human eye and a camera, including: a diaphragm to control the amount of light that gets through to the lens. This is the shutter in a camera, and the pupil, at the center of the iris, in the human eye. a lens to focus the light and create an image. The image is real and inverted. a method of sensing the image. In a camera, film is used to record the image; in the eye, the image is focused on the retina, and a system of rods and cones is the front end of an image-processing system that converts the image to electrical impulses and sends the information along the optic nerve to the brain. The way the eye focuses light is interesting, because most of the refraction that takes place is not done by the lens itself, but by the aqueous humor, a liquid on top of the lens. Light is refracted when it comes into the eye by this liquid, refracted a little more by the lens, and then a bit more by the vitreous humor, the jelly-like substance that fills the space between the lens and the retina. The lens is critical in forming a sharp image, however; this is one of the most amazing features of the human eye, that it can adjust so quickly when focusing objects at different distances. This process of adjustment is known as accommodation. Consider the lens equation: 1/f = 1/di + 1/do With a camera, the lens has a fixed focal length. If the object distance is changed, the image distance (the distance between the lens and the film) is adjusted by moving the lens. This can't be done with the human eye: the image distance, the distance between the lens and the retina, is fixed. If the object distance is changed (i.e., the eye is trying to focus objects that are at different distances), then the focal length of the eye is adjusted to create a sharp image. This is done by changing the shape of the lens; a muscle known as the ciliary muscle does this job. Correcting Nearsightedness: Correcting Farsightedness: Correcting Nearsightedness A person who is nearsighted can only create sharp images of close objects. Objects that are further away look fuzzy because the eye brings them in to focus at a point in front of the retina. To correct for this a lens can be placed in front of the eye. What kind of lens is necessary? A converging lens A diverging lens We need a diverging lens to diverge the light rays just enough so that when the rays are converged by the eye they converge on the retina, creating a focused image. Correcting Farsightedness A farsighted person can only create clear images of objects that are far away. Close objects are brought to a focus behind the retina, which is why they look fuzzy. What kind of lens is needed to correct this? A converging lens A diverging lens

Which animals are arthropods and have eight legs?

All About Arthropods All About Arthropods © Contributed by Leanne Guenther What is an arthropod?  You live with them almost everyday, even in the very cold winter months! They are everywhere and are the largest animal phylum -- about 85% of all known animals in the world are part of this class.   There are far more species of arthropods than there are species in all the other phylums(phyla) combined. Mosquito Photo Source:  Corel Web Gallery Grasshopper Photo Source:  Corel Web Gallery They are spiders, insects, centipedes, mites, ticks, lobsters, crabs, shrimp, crayfish, krill, barnacles, scorpions and many, many others.   Can you see two segments? Photo Source:  Corel Web Gallery Can you see three segments? Photo Source:  Corel Web Gallery The easiest way to tell an arthropod from any other animal is to see if they have: 1) A segmented body. This means that they will have a body made up of more than one part.  Spiders have two segments and flies have three segments. centipede 2) Many jointed legs or limbs. Spiders have 8 legs, millipedes can have...  Hundreds!    Photo Source:  Corel Web Gallery 3)  An exoskeleton. This is an external skeleton. Like armor, it protects the arthropods body.  When arthropods are born the exoskeleton is soft but hardens quickly and it can be shed as the creature grows.  Arthropods are invertebrates; which means that they do not have a backbone. Photo Source:  Corel Web Gallery 4)  Cold blooded Arthropods are cold blooded -- which means, their body temperature depends on the temperature of the environment surrounding them. Photo Source:  Corel Web Gallery Arthropods are some of the most interesting animals in the world! They fly, they creep, and they crawl.  They live on land, in ponds and in the ocean.  From ants to bumblebees, crabs to crayfish, spiders to centipedes -- which are your favorites!?   Scientific stuff:  Arthropods include eleven animal classes Subphylum Chelicerata Class Merostomata (horseshoe crabs, eurypterids)  Class Pycnogonida (sea spiders)  Class Arachnida (spiders, ticks, mites)  Subphylum Crustacea Class Branchiopoda (fairy shrimp, water fleas)  Class Maxillopoda (ostracods, copepods, barnacles)  Class Malacostraca (isopods, amphipods, krill, crabs, shrimp)  Subphylum Uniramia

Which is the modern scientific unit of work and energy?

BBC Bitesize - KS3 Physics - Energy in the home - Revision 1 Energy Energy in the home Energy is measured in J and kJ. Power is the rate of using energy, and is measured in W and kW. Fuel bills show energy used in kWh, and the cost of this can be calculated if the cost per kWh is known. Revise 1 of 3 Energy in food Energy stored in food can be released by combustion (burning) or by respiration in our cells. The labels on packets of food show how much energy is available from the food. A food label on a packet of naan bread. 215 calories is the same as 900 kJ. The amount of energy available may be shown in a unit called the calorie, as in the photograph. However, the scientific unit for energy is the joule , which has the symbol J. A lot of energy is available from most foods, so food labels usually show kJ (kilojoules) instead of J: 1 kJ = 1000 J For example, 2000 J = 2000 ÷ 1000 = 2 kJ. To give you an idea of what 2 kJ can do, it is the energy needed to lift a 100 kg mass by 2 m, or to keep a 20 W electric lamp alight for 100 seconds. The table shows the typical amount of energy available from 100 g of several different foods. The larger the number, the more energy is available. Food

Chlorine, fluorine and bromine belong to which family of elements?

Bromine, Chemical Element - reaction, water, uses, elements, metal, gas, number, name PRONUNCIATION BRO-meen Nearly 90 percent of all bromine produced comes from the United States, Israel, or the United Kingdom. In 1996, about 450,000,000 kilograms (one billion pounds) of the element were produced worldwide. The largest single use of the element is in the manufacture of flame retardants. Flame retardants are chemicals added to materials to prevent burning or to keep them from burning out of control. Other major uses are in the manufacture of drilling fluids, pesticides, chemicals for the purification of water, photographic chemicals, and as an additive to rubber. Discovery and naming Compounds of bromine had been known for hundreds of years before the element was discovered. One of the most famous of these compounds was Tyrian purple, also called royal purple. (Tyrian comes from the word Tyre, an ancient Phoenician city.) Only very rich people or royalty could afford to buy fabric dyed with Tyrian purple. It was obtained from a mollusk (shell fish) found on the shores of the Mediterranean Sea (a large body of water bordered by Europe, Asia, and Africa). In 1825, Löwig enrolled at the University of Heidelberg in Germany to study chemistry. He continued an experiment he had begun at home in which he added chlorine to spring water. The addition of ether to that mixture produced a beautiful red color. Löwig suspected he had discovered a new kind substance. A professor encouraged him by suggesting he study the substance in more detail. As these studies progressed, Balard published a report in a chemical journal that announced the discovery of the new element bromine. The element had all the properties of Löwig's new substance. The two chemists had made the discovery at nearly the same time! Balard, however, is credited as the discoverer of bromine, because scientists acknowledge the first person to publish his or her findings. In Greek, the word bromos means "stench" (strong, offensive odor). Bromine lives up to the description. The odor is intense and highly irritating to the eyes and lungs. Chemists found that bromine belonged in the halogen family. They knew that it had properties similar to other halogens and placed it below fluorine and chlorine in the periodic table. Physical properties Only two liquid elements exist—bromine and mercury. At room temperature, bromine is a deep reddish-brown liquid. It evaporates easily, giving off strong fumes that irritate the throat and lungs. Bromine boils at 58.8°C (137.8°F), and its density is 3.1023 grams per cubic centimeter. Bromine freezes at -7.3°C (18.9°F). A laboratory vessel holds the solid, liquid, and gas states of bromine. Bromine dissolves well in organic liquids—such as ether, alcohol, and carbon tetrachloride—but only slightly in water. Organic compounds contain the element carbon. Chemical properties Bromine is a very reactive element. While it is less reactive than fluorine or chlorine, it is more reactive than iodine. It reacts with many metals, sometimes very vigorously. For instance, with potassium, it reacts explosively. Bromine even combines with relatively unreactive metals, such as platinum and palladium. Occurrence in nature Bromine is too reactive to exist as a free element in nature. Instead, it occurs in compounds, the most common of which are sodium bromide (NaBr) and potassium bromide (KBr). These compounds are found in seawater and underground salt beds. These salt beds were formed in regions where oceans once covered the land. When the oceans evaporated (dried up), salts were left behind—primarily sodium chloride (NaCl), potassium chloride (KCl), and sodium and potassium bromide. Later, movements of the Earth's crust buried the salt deposits. Now they are buried miles undergro

Which was the first antibiotic to be discovered?

First new antibiotic in 30 years discovered in major breakthrough Science First new antibiotic in 30 years discovered in major breakthrough The discovery of Teixobactin could pave the way for a new generation of antibiotics because of the way it was discovered. Sarah Knapton , Science Editor 7 January 2016 • 5:44pm The first new antibiotic to be discovered in nearly 30 years has been hailed as a ‘paradigm shift’ in the fight against the growing resistance to drugs. Teixobactin has been found to treat many common bacterial infections such as tuberculosis, septicaemia and C. diff, and could be available within five years. But more importantly it could pave the way for a new generation of antibiotics because of the way it was discovered. Scientists have always believed that the soil was teeming with new and potent antibiotics because bacteria have developed novel ways to fight off other microbes. But 99 per cent of microbes will not grow in laboratory conditions leaving researchers frustrated  that they could not get to the life-saving natural drugs. Now a team from Northeastern University in Boston, Massachusetts, have discovered a way of using an electronic chip to grow the microbes in the soil and then isolate their antibiotic chemical compounds. They discovered that one compound, Teixobactin, is highly effective against common bacterial infections Clostridium difficile, Mycobacterium tuberculous and Staphylococcus aureus. Professor Kim Lewis, Director of the Antimicrobial Discovery Centre said: “Apart from the immediate implementation, there is also I think a paradigm shift in our minds because we have been operating on the basis that resistance development is inevitable and that we have to focus on introducing drugs faster than resistance “Teixobactin shows how we can adopt an alternative strategy and develop compounds to which bacteria are not resistant.” The first antibiotic Penicillin, was discovered by Alexander Fleming in 1928 and more than 100 compounds have been found since, but no new class has been found since 1987. The lack of new drugs coupled with over-prescribing has led to bacteria becoming increasingly resistant to modern medicines. Dame Sally Davies, the government’s Chief Medical Officer, said antibiotic resistant was ‘as big a risk of terrorism; and warned that Britain faced returning to a 19th century world where the smallest infection or operation could kill. The World Health Oganisation has also classified antimicrobial resistance as a "serious threat’ to every region of the world which ‘has the potential to affect anyone, of any age, in any country" However the new discovery offers hope that many new antibiotics could be found to fight bacterial infections. Crucially, the scientists believe that bacteria will not become resistant to Teixobactin for at least 30 years because of its multiple methods of attack. Testing on mice has already shown that the antibiotic works well at clearing infections, without side-effects. The team is now concentrating on upscaling production so that it could be tested in humans. “Right now we can deliver a dose that cures mice and a variety of models of infection and we can deliver 10 mg per kg so it correlates well with human usage,” added Professor Lewis. The breakthrough was heralded by scientists who said it could prove a ‘game-changer’ in the struggle against antimicrobial resistance. Prof Laura Piddock, Professor of Microbiology at the University of Birmingham, said: “The screening tool developed by these researchers could be a ‘game changer’ for discovering new antibiotics as it allows compounds to be isolated from soil producing micro-organisms that do not grow under normal laboratory conditions.” Prof Mark Woolhouse, Professor of Infectious Disease Epidemiology, from the University of Edinburgh added: “Any report of a new antibiotic is auspicious, but what most excites me about the paper is the tantalising prospect that this discovery is just the tip of the iceberg. “Most antibiotics are natural products derived from microbes in the soil. The ones we have disc

What is the boiling point of water?

What Is the Boiling Point of Water? What Is the Boiling Point of Water? What Is the Boiling Point of Water? Boiling Point of Water The boiling point of water is 100 degrees Celsius or 212 degrees Fahrenheit at 1 atmosphere of pressure (sea level).  Jody Dole, Getty Images Updated July 21, 2016. Question: What Temperature Does Water Boil? At what temperature does water boil? What determines the boiling point of water? Here's the answer to this common question. Answer: The boiling point of water is 100°C or 212° F at 1 atmosphere of pressure (sea level). However, the value is not a constant. The boiling point of water depends on the atmospheric pressure, which changes according to elevation. The boiling point of water is 100°C or 212° F at 1 atmosphere of pressure (sea level), but water boils at a lower temperature as you gain altitude (e.g., on a mountain) and boils at a higher temperature if you increase atmospheric pressure (lived below sea level ). The boiling point of water also depends on the purity of the water. Water which contains impurities (such as salted water ) boils at a higher temperature than pure water. This phenomenon is called boiling point elevation , which is one of the colligative properties of matter. Learn More

Ascorbic acid is which vitamin?

Effective for: Vitamin C deficiency. Taking vitamin C by mouth or injecting as a shot prevents and treats vitamin C deficiency, including scurvy. Also, taking vitamin C can reverse problems associated with scurvy. Likely Effective for: Iron absorption. Administering vitamin C along with iron can increase how much iron the body absorbs in adults and children. A genetic disorder in newborns called tyrosinemia. Taking vitamin C by mouth or as a shot improves a genetic disorder in newborns in which blood levels of the amino acid tyrosine are too high. Possibly Effective for: Age-related vision loss (age-related macular degeneration; AMD). Taking vitamin C in combination with zinc, vitamin E, and beta-carotene daily seems to help prevent vision loss or slow the worsening of AMD in patients with advanced AMD. There is not enough evidence to know if this combination helps people with less advanced macular disease or if it prevents AMD. Using vitamin C with other antioxidants, but without zinc, does not seem to have any effect on AMD. Decreasing protein in the urine (albuminuria). Taking vitamin C plus vitamin E can reduce protein in the urine in people with diabetes. Hardening of the arteries (atherosclerosis). Taking vitamin C by mouth seems to decrease the risk of artery hardening. Vitamin C also appears to slow the rate at which artery hardening worsens. More research is needed to understand the effects of vitamin C intake from the diet or supplements on this condition once it has developed. Cancer. Consuming vitamin C in the diet might decrease the risk of developing mouth cancers and other cancers. Some research suggests that increasing vitamin C intake through fruits and vegetables reduces the risk of cancer. However, taking vitamin C supplements does not appear to reduce cancer risk. Common cold. There is some controversy about the effectiveness of vitamin C for treating the common cold. However, the majority of evidence shows that taking high doses of vitamin C might shorten the course of the cold by 1 to 1.5 days in some patients. Taking vitamin C is not effective for preventing the common cold. Chronic pain condition (complex regional pain syndrome). Taking vitamin C after a wrist fracture seems to decrease the risk of developing a chronic pain condition called complex regional pain syndrome. Kidney problems related to contrast media used during a diagnostic test called angiography. Taking vitamin C before and after an angiography seems to reduce the risk of developing kidney problems. Redness (erythema) after cosmetic skin procedures. There is some evidence that using a particular vitamin C skin cream can decrease the amount and duration of skin redness following laser resurfacing for scar and wrinkle removal. Lung infections caused by heavy exercise. Using vitamin C before heavy physical exercise, such as a marathon, might prevent upper respiratory infections that sometimes follow heavy exercise. Gallbladder disease. There is some evidence that taking vitamin C might help to prevent gallbladder disease in women. However, vitamin C does not seem to have this effect in men. Ulcers in the stomach caused by bacteria called H. pylori. Taking vitamin C seems to decrease some of the side effects caused by treatment for H. pylori infections. After H. pylori bacteria are killed, vitamin C appears to decrease the development of precancerous lesions in the stomach. However, other research suggests that vitamin C does not improve healing from H. pylori infection. Abnormal breakdown of red blood cells (hemolytic anemia). Treatment with vitamin C can improve hemolytic anemia. High blood pressure. Taking vitamin C along with conventional blood pressure-lowering medications appears to decrease systolic blood pressure (the top number in a blood pressure reading) by a small amount, but does not seem to decrease diastolic pressure (the bottom number). Taking vitamin C supplements alone does not seem to affect blood pressure. Lead poisoning. Consuming vitamin C in the diet seems to lower blood levels of lead. Helping medicines used for

What is the generic term for the mechanical, electrical and electronic components of a computer?

Electro-mechanical Technicians : Occupational Outlook Handbook: : U.S. Bureau of Labor Statistics U.S. Bureau of Labor Statistics Summary Electro-mechanical technicians verify dimensions of parts, by using precision measuring instruments, to ensure that specifications are met. Quick Facts: Electro-mechanical Technicians What Electro-mechanical Technicians Do About this section Electro-mechanical technicians install, repair, upgrade, and test electronic and computer-controlled mechanical systems. Electro-mechanical technicians combine knowledge of mechanical technology with knowledge of electrical and electronic circuits. They operate, test, and maintain unmanned, automated, robotic, or electromechanical equipment. Duties Electro-mechanical technicians typically do the following: Read blueprints, schematics, and diagrams to determine the method and sequence of assembly of a part, machine, or piece of equipment Verify dimensions of parts, using precision measuring instruments, to ensure that specifications are met Operate metalworking machines to make housings, fittings, and fixtures Inspect parts for surface defects Repair and calibrate hydraulic and pneumatic assemblies  Test the performance of electro-mechanical assemblies, using test instruments Install electronic parts and hardware, using soldering equipment and hand tools Operate, test, or maintain robotic equipment Analyze and record test results, and prepare written documentation Electro-mechanical technicians test and operate machines in factories and other worksites. They also analyze and record test results, and prepare written documentation to describe the tests they did and what the test results were. Electro-mechanical technicians install, maintain, and repair automated machinery and equipment in industrial settings. This kind of work requires knowledge and training in the application of photonics, the science of light. The technological aspects of the work have to do with the generating, controlling, and detecting of the light waves so that the automated processes can proceed as designed by the engineers. Electro-mechanical technicians also test, operate, or maintain robotic equipment at worksites. This equipment may include unmanned submarines, aircraft, or similar types of equipment for uses including oil drilling, deep-ocean exploration, or hazardous-waste removal. Work Environment About this section Electro-mechanical technicians test the performance of electro-mechanical assemblies, using test instruments. Electro-mechanical technicians held about 14,700 jobs in 2014. The industries that employed the most electro-mechanical technicians were as follows: Navigational, measuring, electromedical, and control instruments manufacturing 13% Machinery manufacturing 7 Electro-mechanical technicians work closely with electrical and mechanical engineers . They work in many industrial environments, including energy, plastics, computer, and communications equipment manufacturing, and aerospace. They often work both at production sites and in offices. Because their job involves manual work with many machines and types of equipment, electro-mechanical technicians are sometimes exposed to hazards from equipment or toxic materials. However, incidents are rare as long as they follow proper safety procedures. Work Schedules Electro-mechanical technicians often work for larger companies in manufacturing or for engineering firms. Like others at these firms, these technicians tend to work regular shifts. However, sometimes they must work longer hours to make repairs so that manufacturing operations can continue. How to Become an Electro-mechanical Technician About this section Electro-mechanical technicians typically need either an associate’s degree or a postsecondary certificate. Electro-mechanical technicians typically need either an associate’s degree or a postsecondary certificate. Education Associate’s degree programs and postsecondary certificates for electro-mechanical technicians are offered at vocational–technical schools and community colleges. Vocatio

Whose research on X-ray diffraction of ?DNA crystals helped Crick and Watson during the race to discover the structure of DNA?

A Science Odyssey: People and Discoveries: Watson and Crick describe structure of DNA Watson and Crick describe structure of DNA 1953 Photo: Model of DNA molecule In the late nineteenth century, a German biochemist found the nucleic acids, long-chain polymers of nucleotides, were made up of sugar, phosphoric acid, and several nitrogen-containing bases. Later it was found that the sugar in nucleic acid can be ribose or deoxyribose, giving two forms: RNA and DNA. In 1943, American Oswald Avery proved that DNA carries genetic information. He even suggested DNA might actually be the gene. Most people at the time thought the gene would be protein, not nucleic acid, but by the late 1940s, DNA was largely accepted as the genetic molecule. Scientists still needed to figure out this molecule's structure to be sure, and to understand how it worked. In 1948, Linus Pauling discovered that many proteins take the shape of an alpha helix, spiraled like a spring coil. In 1950, biochemist Erwin Chargaff found that the arrangement of nitrogen bases in DNA varied widely, but the amount of certain bases always occurred in a one-to-one ratio. These discoveries were an important foundation for the later description of DNA. In the early 1950s, the race to discover DNA was on. At Cambridge University, graduate student Francis Crick and research fellow James Watson (b. 1928) had become interested, impressed especially by Pauling's work. Meanwhile at King's College in London, Maurice Wilkins (b. 1916) and Rosalind Franklin were also studying DNA. The Cambridge team's approach was to make physical models to narrow down the possibilities and eventually create an accurate picture of the molecule. The King's team took an experimental approach, looking particularly at x-ray diffraction images of DNA. In 1951, Watson attended a lecture by Franklin on her work to date. She had found that DNA can exist in two forms, depending on the relative humidity in the surrounding air. This had helped her deduce that the phosphate part of the molecule was on the outside. Watson returned to Cambridge with a rather muddy recollection of the facts Franklin had presented, though clearly critical of her lecture style and personal appearance. Based on this information, Watson and Crick made a failed model. It caused the head of their unit to tell them to stop DNA research. But the subject just kept coming up. Franklin, working mostly alone, found that her x-ray diffractions showed that the "wet" form of DNA (in the higher humidity) had all the characteristics of a helix. She suspected that all DNA was helical but did not want to announce this finding until she had sufficient evidence on the other form as well. Wilkins was frustrated. In January, 1953, he showed Franklin's results to Watson, apparently without her knowledge or consent. Crick later admitted, "I'm afraid we always used to adopt -- let's say, a patronizing attitude towards her." Watson and Crick took a crucial conceptual step, suggesting the molecule was made of two chains of nucleotides, each in a helix as Franklin had found, but one going up and the other going down. Crick had just learned of Chargaff's findings about base pairs in the summer of 1952. He added that to the model, so that matching base pairs interlocked in the middle of the double helix to keep the distance between the chains constant. Watson and Crick showed that each strand of the DNA molecule was a template for the other. During cell division the two strands separate and on each strand a new "other half" is built, just like the one before. This way DNA can reproduce itself without changing its structure -- except for occasional errors, or mutations. The structure so perfectly fit the experimental data that it was almost immediately accepted. DNA's discovery has been called the most important biological work of the last 100 years, and the field it opened may be the scientific frontier for the next 100. By 1962, when Watson, Crick, and Wilkins won the Nobel Prize for physiology/medicine, Franklin had died. The Nobel Prize only goes to living

Heisenberg is most associated with which branch of physics?

The Uncertainty Principle (Stanford Encyclopedia of Philosophy) Stanford Encyclopedia of Philosophy The Uncertainty Principle First published Mon Oct 8, 2001; substantive revision Tue Jul 12, 2016 Quantum mechanics is generally regarded as the physical theory that is our best candidate for a fundamental and universal description of the physical world. The conceptual framework employed by this theory differs drastically from that of classical physics. Indeed, the transition from classical to quantum physics marks a genuine revolution in our understanding of the physical world. One striking aspect of the difference between classical and quantum physics is that whereas classical mechanics presupposes that exact simultaneous values can be assigned to all physical quantities, quantum mechanics denies this possibility, the prime example being the position and momentum of a particle. According to quantum mechanics, the more precisely the position (momentum) of a particle is given, the less precisely can one say what its momentum (position) is. This is (a simplistic and preliminary formulation of) the quantum mechanical uncertainty principle for position and momentum. The uncertainty principle played an important role in many discussions on the philosophical implications of quantum mechanics, in particular in discussions on the consistency of the so-called Copenhagen interpretation, the interpretation endorsed by the founding fathers Heisenberg and Bohr. This should not suggest that the uncertainty principle is the only aspect of the conceptual difference between classical and quantum physics: the implications of quantum mechanics for notions as (non)-locality, entanglement and identity play no less havoc with classical intuitions. Related Entries 1. Introduction The uncertainty principle is certainly one of the most famous aspects of quantum mechanics. It has often been regarded as the most distinctive feature in which quantum mechanics differs from classical theories of the physical world. Roughly speaking, the uncertainty principle (for position and momentum) states that one cannot assign exact simultaneous values to the position and momentum of a physical system. Rather, these quantities can only be determined with some characteristic “uncertainties” that cannot become arbitrarily small simultaneously. But what is the exact meaning of this principle, and indeed, is it really a principle of quantum mechanics? (In his original work, Heisenberg only speaks of uncertainty relations.) And, in particular, what does it mean to say that a quantity is determined only up to some uncertainty? These are the main questions we will explore in the following, focusing on the views of Heisenberg and Bohr. The notion of “uncertainty” occurs in several different meanings in the physical literature. It may refer to a lack of knowledge of a quantity by an observer, or to the experimental inaccuracy with which a quantity is measured, or to some ambiguity in the definition of a quantity, or to a statistical spread in an ensemble of similarly prepared systems. Also, several different names are used for such uncertainties: inaccuracy, spread, imprecision, indefiniteness, indeterminateness, indeterminacy, latitude, etc. As we shall see, even Heisenberg and Bohr did not decide on a single terminology for quantum mechanical uncertainties. Forestalling a discussion about which name is the most appropriate one in quantum mechanics, we use the name “uncertainty principle” simply because it is the most common one in the literature. 2. Heisenberg 2.1 Heisenberg’s road to the uncertainty relations Heisenberg introduced his famous relations in an article of 1927, entitled Ueber den anschaulichen Inhalt der quantentheoretischen Kinematik und Mechanik. A (partial) translation of this title is: “On the anschaulich content of quantum theoretical kinematics and mechanics”. Here, the term anschaulich is particularly notable. Apparently, it is one of those German words that defy an unambiguous translation into other languages. Heisenberg’s title is translated as “On

What did Heike Kamerlingh-Onnes discover?

Heike Kamerlingh Onnes - Biography, Facts and Pictures Blog Heike Kamerlingh Onnes A Dutch physicist, Heike Kamerlingh Onnes was the pioneer of refrigeration techniques and the one who studied how materials behave when they are cooled to almost absolute zero temperature. He was also the first person to liquefy helium, and because of his experiments concerning cryogenics as well as extremely low temperature, he was able to discover superconductivity. He also noted how the rate of electrical resistance can vanish at much lower temperatures for certain materials. Early Life and Educational Background Heike was born on the 21st of September in 1853 and was a native of Groningen in the Netherlands. Harm Kamerlingh Onnes, his father, owned brickworks near his birth town. Anna Gerdina Coers, his mother, was an architect’s daughter from Arnhem. His exposure to such fields may have piqued his interest when it came to making his very own discoveries later on in his life. Advertisements He was educated at the local Hoogere Burgerschool which was a native secondary school that did not have classical languages. After spending the required time for secondary school, he was able to get supplementary education on Latin and Greek from Leyden J.M. van Bemmelen who later became his Chemistry professor. After his supplementary education on classical languages, he went to the University of Groningen where he worked on obtaining the “candidaats” degree. A year after studying at the University of Groningen, he proceeded to Heidelberg where he furthered his education from 1871 up to 1873. After his time there, he made his way back to Groningen and this was where he was able to pass his “doctoraal” exams in 1879. A year later, he was able to obtain his doctoral degree and he had his thesis called the New Proofs of the Rotation of the Earth which was originally entitled Nieuwebewijzenvoor de aswenteling der aarde. In this doctoral work, he proved through theoretical and experimental means how the Foucault’s pendulum experiment must be seen as a kind of special, large group phenomena which, when simplified, can prove how the earth moved in a rotational manner. In 1881, Heike published Algemeenetheorie der vloeistoffen or the general theory of liquids which discussed the kinetic theory of matter in liquid state. Here, he approached his work using the Van der Waal law while also having a mechanistic back up to it. His work on the general theory of liquids sparked his lifelong dedication to investigate more on how matter behaves when subjected to very low temperatures. He had his inaugural address known as the importance of quantitative research in physics where he said his now famous motto: “Knowledge through measurement” or “Door metentotweten.” Little did he realize this belief had materialized because of his appreciation of how important measurements were concerning his lifelong engagement in scientific experiments. Scientific Career and Endeavors It was in 1871 when his outstanding skills in solving scientific problems were made obvious at the young age of 18. That year he received a gold medal for winning a competition which was held by the University of Utrecht’s Natural Sciences Faculty. The following year he received a silver medal from the University of Groningen. While he was still working on his doctoral degree, he was an assistant at the Polytechnicum which was in Delft. He also became a lecturer in the area for a year from 1881. Because of this, he was appointed as the Professor of Experimental Physics and Meteorology after P.L. Rijke held the same post. After he got appointed as the chair of Physics, he made changes to the Physical Laboratory which is now named after him and is called the Kamerlingh Onnes Laboratory. He made the necessary changes so that the place would be fitted to be the most suitable place for his own program. More particularly, the changes he made were aimed towards having his own cryogenic laboratory that would help him verify the idea Van der Waal had about corresponding states of matter in relation to the temper

What science is the study of missiles in motion?

ballistics Encyclopedia  >  Science and Technology  >  Physics  >  Physics ballistics ballistics (bəlĭsˈtĭks) [ key ], science of projectiles. Interior ballistics deals with the propulsion and the motion of a projectile within a gun or firing device. Its problems include the ignition and burning of the propellant powder, the pressure produced by the expanding gases, the movement of the projectile through the bore, and the designing of the barrel to resist resulting stresses and strains. Exterior ballistics is concerned with the motion of a projectile while in flight and includes the study not only of the flight path of bullets but also of bombs, rockets, and missiles. All projectiles traveling through the air are affected by wind, air resistance, and the force of gravity. These forces induce a curved path known as a trajectory. The trajectory varies with the weight and shape of the projectile, with its initial velocity, and with the angle at which it is fired. The general shape of a trajectory is that of a parabola. The total distance traveled by a projectile is known as its range. A ballistic missile in the first stage of its flight is powered and guided by rocket engines. After the engines burn out, the warhead travels in a fixed arc as does an artillery shell. In criminology the term ballistics is applied to the identification of the weapon from which a bullet was fired. Microscopic imperfections in a gun barrel make characteristic scratches and grooves on bullets fired through it, but use causes the marks a particular gun makes to change over time. See E. D. Lowry, Interior Ballistics (1968); R. C. Labile, Ballistic Materials and Penetration Mechanics (1980); A. J. Pejsa, Modern Practical Ballistics (1989); M. Denny, Their Arrows Will Darken the Sun: The Evolution and Science of Ballistics (2011). The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved. See more Encyclopedia articles on: Physics

What kind of elements are found in a pure state in nature?

Elements and Compounds About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Elements and Compounds An element is a material that consists of a single type of atom, while a compound consists of two or more types of atoms. Learning Objective Differentiate between elements and compounds and explore separation techniques Key Points Elements are the simplest complete chemical substances . Each element corresponds to a single entry on the periodic table. An element is a material that consists of a single type of atom . Each atom type contains the same number of protons . Chemical bonds link elements together to form more complex molecules called compounds . A compound consists of two or more types of elements held together by covalent or ionic bonds . Elements cannot be divided into smaller units without large amounts of energy . Compounds, on the other hand, can have their bonds broken with practical amounts of energy, such as the heat from a fire. Matter can be broken down into two categories: pure substances and mixtures . Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated back into their original components. Terms Full Text Elements A chemical element is a pure substance that consists of one type of atom. Each atom has an atomic number , which represents the number of protons that are in the nucleus of a single atom of that element. The periodic table of elements is ordered by ascending atomic number. The chemical elements are divided into the metals , the metalloids , and the non-metals. Metals, typically found on the left side of the periodic table, are: often conductive to electricity sometimes magnetic. Aluminum , iron, copper , gold, mercury and lead are metals. In contrast, non-metals, found on the right side of the periodic table (to the right of the staircase), are: typically not conductive not magnetic. Examples of elemental non-metals include carbon and oxygen . Metalloids have some characteristics of metals and some characteristics of non-metals. Silicon and arsenic are metalloids. As of November, 2011, 118 elements have been identified (the most recently identified was ununseptium, in 2010). Of these 118 known elements, only the first 98 are known to occur naturally on Earth. The elements that do not occur naturally on Earth are the synthetic products of man-made nuclear reactions. 80 of the 98 naturally-occurring elements are stable; the rest are radioactive, which means they decay into lighter elements over timescales ranging from fractions of a second to billions of years. The periodic table shows 118 elements, including metals (blue), nonmetals (red), and metalloids (green). Hydrogen and helium are by far the most abundant elements in the universe. However, iron is the most abundant element (by mass) in the composition of the Earth, and oxygen is the most common element in the layer that is the Earth's crust. Although all known chemical matter is composed of these elements, chemical matter itself constitutes only about 15% of the matter in the universe. The remainder is dark matter, a mysterious substance that is not composed of chemical elements. Dark matter lacks protons, neutrons , or electrons . Compounds Pure samples of isolated elements are uncommon in nature. While the 98 naturally occurring elements have all been identified in mineral samples from the Earth's crust, only a small minority of them can be found as recognizable, relatively pure minerals. Among the more common of such "native elements" are copper, silver , gold, and sulfur. Carbon is also commonly found in the form of coal, graphite, and diamonds . The noble gases (e.g., neon) and noble metals (e.g., mercury) can also be

"What are classified by their measurement in degrees as ""right"", ""reflex"", ""obtuse"", or ""acute""?"

Angles - Acute, Obtuse, Straight and Right Angles An angle measures the amount of turn Names of Angles As the Angle Increases, the Name Changes: Type of Angle an angle that is greater than 90° but less than 180° an angle that is greater than 180° Try It Yourself: This diagram might make it easier to remember: Also: Acute, Obtuse and Reflex are in alphabetical order.   Also: the letter "A" has an acute angle. Be Careful What You Measure This is an Obtuse Angle And this is a Reflex Angle   But the lines are the same ... so when naming the angles make sure that you know which angle is being asked for! Positive and Negative Angles When measuring from a line: a positive angle goes counterclockwise (opposite direction that clocks go) a negative angle goes clockwise Example: −67° The corner point of an angle is called the vertex And the two straight sides are called arms The angle is the amount of turn between each arm.   How to Label Angles There are two main ways to label angles: 1. give the angle a name, usually a lower-case letter like a or b, or sometimes a Greek letter like α (alpha) or θ (theta) 2. or by the three letters on the shape that define the angle, with the middle letter being where the angle actually is (its vertex). Example angle "a" is "BAC", and angle "θ" is "BCD"

What is the name given to the longest side of a right-angled triangle?

Naming the Sides of a Right-Angled Triangle Year 10 Interactive Maths - Second Edition Naming the Sides of a Right-Angled Triangle The side opposite the right angle is called the hypotenuse.  It is the largest side of a right-angled triangle. If you stand at A in the triangle ABC, the side BC is opposite to you and the side AB is next to you.  We therefore say that BC is the opposite side to angle A and AB is the adjacent side to angle A. Notation If you have trouble remembering the definitions, just remember SOH CAH TOA. Using a Graphics Calculator If you have a TI-83 graphics calculator, select Degree from the MODE menu and set Float to 4 to obtain the answers correct to 4 decimal places.  Press QUIT to return to the Home Screen and clear the screen if necessary. If you are using another calculator, consult its instruction booklet or ask your teacher how you can set its Mode to 'Degree mode' and the decimal places display to 4 places. Example 1 Evaluate the following to 4 decimal places: Solution: This is abbreviated as follows: Example 2 Note: Key Terms

Which Swedish scientist had a temperature scale named after him?

Anders Celsius - Centigrade Scale and Thermometer By Mary Bellis In 1742, Swedish astronomer, Anders Celsius invented the Celsius temperature scale, which was named after the inventor. Celsius Temperature Scale The Celsius temperature scale is also referred to as the centigrade scale. Centigrade means "consisting of or divided into 100 degrees". The Celsius scale, invented by Swedish Astronomer Anders Celsius (1701-1744), has 100 degrees between the freezing point (0 C) and boiling point (100 C) of pure water at sea level air pressure. The term "Celsius" was adopted in 1948 by an international conference on weights and measures. Anders Celsius Anders Celsius was born in Uppsala, Sweden in 1701, where he succeeded his father as professor of astronomy in 1730. It was there that he built Sweden's first observatory in 1741, the Uppsala Observatory, where he was appointed director. He devised the centigrade scale or "Celsius scale" of temperature in 1742. He was also noted for his promotion of the Gregorian calendar, and his observations of the aurora borealis. continue reading below our video 5 Best Places to Retire In 1733, his collection of 316 observations of the aurora borealis was published and in 1737 he took part in the French expedition sent to measure one degree of meridian in the polar regions. In 1741, he directed the building of Sweden's first observatory. One of the major questions of that time was the shape of the Earth. Isaac Newton had proposed that the Earth was not completely spherical, but rather flattened at the poles. Cartographic measuring in France suggested that it was the other way around - the Earth was elongated at the poles. In 1735, one expedition sailed to Ecuador in South America, and another expedition traveled to Northern Sweden. Celsius was the only professional astronomer on that expedition. Their measurements seemed to indicate that the Earth actually was flattened at the poles. Anders Celsius was not only an inventor and astronomer, but also a physicist. He and an assistant discovered that the aurora borealis had an influence on compass needles. However, the thing that made him famous is his temperature scale, which he based on the boiling and melting points of water. This scale, an inverted form of Celsius' original design, was adopted as the standard and is used in almost all scientific work. Anders Celsius died in 1744, at the age of 42. He had started many other research projects, but finished few of them. Among his papers was a draft of a science fiction novel, situated partly on the star Sirius.

How many colors are there in the spectrum when white light is separated?

Red .622-.780 Like energy passing through the ocean, light energy travels in waves, too. Some light travels in short, "choppy" waves. Other light travels in long, lazy waves. Blue light waves are shorter than red light waves. All light travels in a straight line unless something gets in the way to-- reflect it (like a mirror) bend it (like a prism) or scatter it (like molecules of the gases in the atmosphere) Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Blue is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time. Closer to the horizon, the sky fades to a lighter blue or white. The sunlight reaching us from low in the sky has passed through even more air than the sunlight reaching us from overhead. As the sunlight has passed through all this air, the air molecules have scattered and rescattered the blue light many times in many directions. Also, the surface of Earth has reflected and scattered the light. All this scattering mixes the colors together again so we see more white and less blue. Why do we see rainbows in the sky?  A rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines onto droplets of moisture in the Earth's atmosphere. They take the form of a multi-colored arc, with red on the outer part of the arch and violet on the inner section of the arch. A rainbow spans a continuous spectrum of colors. Traditionally, however, the sequence is quantised. The most commonly cited and remembered sequence, in English, is Newton's sevenfold in order from longest to shortest wavelength: red, orange, yellow, green, blue, indigo and violet.  "Roy G. Biv" and "Richard Of York Gave Battle In Vain" are popular mnemonics. Rainbows can be caused by other forms of water than rain, including mist, spray, and dew. Sunlight contains many different colors. Normally, we see all the colors mixed together as white light. We see a rainbow when sunlight separates into bands of different colors. These bands of red, orange, yellow, green, blue, indigo, and violet light are also known as the visible spectrum.  A rainbow is created when sunlight passes through raindrops. Light travels through different substances at different speeds. When light travels through water, it slows down. The reduced speed causes light to bend or refract.  To understand how a rainbow is made, it is helpful to understand how a prism works. A prism is a triangular shaped piece of glass. The path of a light beam changes as it goes through a prism. Glass slows the speed of light. When light travels through a prism, it is refracted once while going in and again as it passes through. The refraction separates white light into its many colors.  A water drop acts like a prism. Light refracts as it enters and leaves a drop of water. The refracting light is separated into the colors of the spectrum. When the sky is filled with drops of water, a rainbow is created. Light that enters the drops is refracted. Refraction makes each color visible in its own band. Each color of the spectrum has a slightly different wavelength. The different wavelengths bend in slightly different ways. Long wavelengths bend the least, while short wavelengths refract the most. Red light has the longest wavelength and violet light has the shortest. The other colors have wavelengths that fall between. Because color refraction is consistent, the colors of the rainbow or any other spectrum look the same and appear in the same order. We use the memory device ROYGBV (Roy G. Biv) to signify the order of colors.  The combination of all the separated colors creates the beautiful arching rainbow. Since light needs to pass through the raindrops, rainbows are always seen in the part of the sky opposite the Sun. We see the colors of a typical rainbow as lig

The discovery of which law provoked the surprised cry 'Eureka!'?

PHYSICS FOLIO |authorSTREAM PHYSICS FOLIO   Does not support media & animations   Automatically changes to Flash or non-Flash embed   The presentation is successfully added In Your Favorites . Views:   This Presentation is Public   Favorites:  0 ENTRY NO. 1: Physics A Natural Philosophy: ENTRY NO. 1: Physics A Natural Philosophy ENTRY NO. 1: Physics A Natural Philosophy Physics A Natural Philosophy: Physics A Natural Philosophy Physics as natural philosophy. Physics is present in our environment at all times. The gravitational theory is the perfect explanation for this natural philosophy. Gravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their mass. In everyday life, gravitation is most familiar as the agent that gives weight to objects with mass and causes them to fall to the ground when dropped. ENTRY NO.2 PHYSICS REALLY WORKS: ENTRY NO.2 PHYSICS REALLY WORKS Physics Really Works: Physics Really Works Physics really works. A branch of physics, which is electromagnetism, can be seen in modern inventions. Electromagnetism is the force that causes the interaction between electrically charged particles; the areas in which this happens are called electromagnetic fields. This is the set-up in a MICROPHONE. sound waves enter the microphone, which cause the microphone to vibrate back and forth. This subsequently causes the wire loops to oscillate, and the magnetic field through the plane of the loops subsequently changes, inducing a current in the wires. In this way sound or wave energy is converted into electrical energy. ENTRY NO. 3: TESTING TIME : ENTRY NO. 3: TESTING TIME PHYSICS TRIVIAS:: PHYSICS TRIVIAS: Q:  What did scientists build in a squash court under a football stadium at the University of Chicago in 1942? A:  A nuclear reactor. Slide 8: Q: Which Swedish scientist had a temperature scale named after him? A: Anders Celsius. Slide 9: Q :What is the term used to denote the tendency of an object to remain in a state of rest until acted upon by an external force? A: Inertia. Slide 10: Q: The discovery of which law provoked the surprised cry 'Eureka!'? A: Archimedes Principle. Slide 11: Q: Which electronic device magnifies the strength of a signal? A: Amplifier. Slide 12: Q :What is an unchanging position in which forces cancel each other out? A: Equilibrium. Slide 13: Q: What was the name of the unit of heat now replaced by the joule? A: Calorie. Slide 14: Q: What is described as an ionized gas with approximately equal numbers of positive and negative charges? A: Plasma. ENTRY NO. 4: EUREKA EXPERIENCE: ENTRY NO. 4: EUREKA EXPERIENCE My Eureka Experience..: My Eureka Experience.. I have learned a lot of things in my fourth year life now. One of those lessons I’ve learned was the accuracy of measurement. Once we where able to measure using the Vernier caliper. First it was so hard because I’m not familiar with it but Aldrin teach me and now I know how to read its measurement. Eureka! Eureka! ENTRY NO. 5: MEDIA HYPE: ENTRY NO. 5: MEDIA HYPE Media Hype: Media Hype The advertisement of the shampoos and conditioners are one of the best example of media hype. The commercial says that you will have a smoother and healthier hair just like when you go to the parlor. These models and endorsers have some hair treatment before the shoot and some are made by the camera tricks for the commercial so that it will look more beautiful and real. Slide 21: Commercials told us that their products can make our clothes whiter from having dirt after we washed them. They illustrate their product and another product and compared it from one another. The t-shirt that been soaked in their product was much whiter than the other but it looks like it’s a new one and not the original one. Old Quill to Ordinary pen and now. Pen with USB.. At the early age they used the old quill just like Jose Rizal and now there's a lot of hi-tech pens. Pens with camera, with USB or sometimes made from gold.: Old Quill to Ordinary pen and now. Pen with USB.. At the early age they used the old

What is the study and use of frequencies above 20 khz?

There's life above 20 kilohertz! A survey of musical instrument spectra to 102.4 kHz   Author's Notes, May 4, 2000 At the request of people involved in standards-setting for audio, who wanted this information made available as soon as possible, I published this original paper here, rather than in a professional journal. Because I use figures 1(a,b,c) not only as data but to explain my reasoning, I include them in the paper itself. To save download time, other figures are given as links. After you look at one of these figures, your browser's "Back" button may return you to exactly where you were in the paper. If it doesn't, please note what section of the paper you are in before you link to the figure, then return by using the section links supplied with each figure. The footnotes have links to return you to where they were cited. All of the figures are 900 pixels wide. Viewing will be easiest on a monitor screen of 1024 x 768 or higher resolution, and with 256 or more colors.   III. More trumpet, horn, violin, and oboe In the same way as just described for Figure 1, Figures 2 through 9 give information about other instruments whose sound has harmonics.       Skipping Figure 1(c) for the moment, in Figure 2 we see another sample of trumpet with Harmon mute, 20 dB lower in level than the sample in Figure 1, yet with harmonics extending higher, and with a higher percentage of its total energy in the harmonics. (See Table I.) Figure 3 shows trumpet with straight mute. Here the harmonics extend higher yet, to above 85 kHz.       Figures 4 , 5 , and 6 give three examples of French horn, played respectively "bell up," with mute, and in normal fashion. One hundred or more harmonics are visible in each!        Figure 7 shows a violin "double-stop", that is, two notes played simultaneously. Since each note produces its own harmonic series, Figure 7(b) uses markers of two different shapes to show the two harmonic series.        Figure 8 shows a single violin note played sul ponticello, that is, with the bow very close to the bridge. This gives a distinctive squeaky-scratchy sound which composers sometimes specify, as for example Beethoven in the C-sharp Minor string quarter, Opus 131. Even in this mezzo-piano (medium-soft) note, harmonics are still visible past 40 kHz. (Due to absence of mind, I took no sample of normal violin sound playing a single note normally.)        Figure 9 shows an oboe note. It is striking how the harmonics suddenly drop in level after the 40th at 43 kHz.       Not shown are any clarinet or vibraphone samples, because, as mentioned above, I could find no harmonic activity above 20 kHz anywhere in several samples of each, despite the closest "prospecting" with spectrum analyzer. These were the only instruments of the group that did not show such activity.         Figures 18(a) and (b) show the performance of the B&K preamp to signals (c) and (d) respectively. The preamp is clearly free of harmonics at both high and low levels. The small bump at 85 kHz in the low-level test is breakthrough from the switching power supply. [3] I don't know the source of the even smaller bump at 50 kHz. Both are so small that they may be ignored, however.       The behavior of the Aco 4012 preamp was indistinguishable from the B&K 2639 at the higher level, and superior at the lower.       Note that these tests of the preamps are also tests of the H-P 3567A FFT analyzer. From the clean results, one may conclude that neither preamps nor analyzer are creating a false appearance in any of the spectra in this paper.   V. Room acoustics and rattles I assume that the room acoustics are linear, and thus cannot create spurious frequencies in the spectrum. On the other hand, the room does contain objects which could conceivably rattle at ultrasonic frequencies, including loudspeakers, vacuum tubes, fluorescent light fixtures, metal chassis, and so on. What is more, the time samples analyzed for instruments with harmonics were generally long enough (31.25 milliseconds) for the microphone to pick up not only the direct sound of the instru

What is an unchanging position in which forces cancel each other out?

Equilibria - definition of equilibria by The Free Dictionary Equilibria - definition of equilibria by The Free Dictionary http://www.thefreedictionary.com/equilibria Related to equilibria: Punctuated equilibria e·qui·lib·ri·um  (ē′kwə-lĭb′rē-əm, ĕk′wə-) n. pl. e·qui·lib·ri·ums or e·qui·lib·ri·a (-rē-ə) 1. A condition in which all acting influences are canceled by others, resulting in a stable, balanced, or unchanging system. 2. Mental or emotional balance. 3. Physics The state of a body or physical system at rest or in unaccelerated motion in which the resultant of all forces acting on it is zero and the sum of all torques about any axis is zero. 4. Chemistry a. The state of a chemical reaction in which its forward and reverse reactions occur at equal rates so that the concentration of the reactants and products does not change with time. b. The state of a system in which more than one phase exists and exchange between phases occurs at equal rates so that there is no net change in the composition of the system. [Latin aequilībrium : aequi-, equi- + lībra, balance.] equilibrium n, pl -riums or -ria (-rɪə) 1. a stable condition in which forces cancel one another 2. a state or feeling of mental balance; composure 3. (General Physics) any unchanging condition or state of a body, system, etc, resulting from the balance or cancelling out of the influences or processes to which it is subjected. See thermodynamic equilibrium 4. (General Physics) physics a state of rest or uniform motion in which there is no resultant force on a body 5. (Chemistry) chem the condition existing when a chemical reaction and its reverse reaction take place at equal rates 6. (General Physics) physics the condition of a system that has its total energy distributed among its component parts in the statistically most probable manner 7. (Physiology) physiol a state of bodily balance, maintained primarily by special receptors in the inner ear 8. (Economics) the economic condition in which there is neither excess demand nor excess supply in a market [C17: from Latin aequilībrium, from aequi- equi- + lībra pound, balance] e•qui•lib•ri•um (ˌi kwəˈlɪb ri əm, ˌɛk wə-) n., pl. -ri•ums, -ri•a (-ri ə) 1. a state of rest or balance due to the equal action of opposing forces. 2. equal balance between any powers, influences, etc.; equality of effect. 3. mental or emotional balance; equanimity. 4. a state or sense of steadiness and proper orientation of the body. 5. the condition existing when a chemical reaction and its reverse reaction proceed at equal rates. [1600–10; < Latin aequilībrium=aequi- equi - + lībr(a) balance] e•quil′i•bra•to`ry (ɪˈkwɪl ə brəˌtɔr i, -ˌtoʊr i) adj. e·qui·lib·ri·um (ē′kwə-lĭb′rē-əm) 1. Physics The state of a body or physical system that is at rest or in constant and unchanging motion. The sum of all forces acting on a body that is in equilibrium is zero (because opposing forces balance each other). A system that is in equilibrium shows no tendency to alter over time. 2. Chemistry The state of a reversible chemical reaction in which its forward and reverse reactions occur at equal rates so that the concentration of the reactants and products remains the same. equilibrium The state of a reversible chemical reaction at which the forward and backward reactions take place at the same rate ThesaurusAntonymsRelated WordsSynonymsLegend:

Which physicist's law states that equal volumes of all gases, measured at the same temperature and pressure, contain the same number of molecules?

General Chemistry/Gases - Wikibooks, open books for an open world General Chemistry/Gases 3.2 Pressure and Collisions Characteristics of Gases[ edit ] Gases have a number of special characteristics that differentiate them from other states of matter. Here is a list of characteristics of gases: Characteristics of Gases Gases have neither definite shape nor definite volume. They expand to the size of their container. Gases are fluid, and flow easily. Gases have low density, unless compressed. Being made of tiny particles in a large, open space, gases are very compressible. Gases diffuse (mix and spread out) and effuse (travel through small holes). Standard Temperature and Pressure[ edit ] Wikipedia has related information at Standard conditions for temperature and pressure Standard Temperature and Pressure, or STP, is 0 °C and 1 atmosphere of pressure. Expressed in other units, STP is 273 K and 760 torr. The Kelvin and torr are useful units of temperature and pressure respectively that we will discuss later in the following sections. Avogadro's Law[ edit ] Amedeo Avogadro, the Italian chemist. Avogadro's Law is named after him and his discoveries about the behavior of gases Wikipedia has related information at Avogadro's Law Avogadro's Law states that equal volumes of gases at the same temperature and pressure contain the same number of molecules. So both one mole of Xenon at STP (131.3 grams) and one mole of helium at STP (4.00 grams) take up 22.4 liters. Even 1 mole of air, which is a mixture of several gases, takes up 22.4 liters of volume. 22.4 L is the standard molar volume of a gas. [Avogadro's Law] s t {\displaystyle {\frac {p_{1}\cdot V_{1}}{T_{1}\cdot n_{1}}}={\frac {p_{2}\cdot V_{2}}{T_{2}\cdot n_{2}}}=const} where: p is the pressure of the gas T is the temperature of the gas has the same value for all gases, independent of the size or mass of the gas molecules. Pressure[ edit ] Gases exert pressure on their containers and all other objects. Pressure is measured as force per unit area. A barometer is a device that measures pressure. There are a number of different units to measure pressure: torr, equal to millimeters of mercury (mm Hg): if a glass cylinder with no gas in it is placed in a dish of liquid mercury, the mercury will rise in the cylinder to a certain number of millimeters. atmosphere (atm), the pressure of air at sea level. pascal (Pa), equal to one newton (N) per square meter. A newton is the force necessary to accelerate one kilogram by one meter per second squared. You should know that 1 atm = 760 torr = 101.3 kPa. Wikipedia has related information at Ideal gas Gases are complicated things composed a large numbers of tiny particles zipping around at high speeds. There are a number of complex forces governing the interactions between molecules in the gas, which in turn affect the qualities of the gas as a whole. To get around these various complexities and to simplify our study, we will talk about ideal gases. An ideal gas is a simplified model of a gas that follows several strict rules and satisfies several limiting assumptions. Ideal gases can be perfectly modeled and predicted with a handful of equations. Ideal gases follow, among others, these important rules: Rules of Ideal Gases The molecules that make up a gas are point masses, meaning they have no volume. Gas particles are spread out with very great distance between each molecule. Thus, intermolecular forces are essentially zero, meaning they neither attract nor repel each other. If collisions do occur between gas particles, these collisions are elastic, meaning there is no loss of kinetic (motion) energy. Gas molecules are in continuous random motion. Temperature is directly proportionate to kinetic energy. Note: Ideal gases never truly exist (because the nature of gases is so complicated), but gases are often close enough to an ideal gas that the equations still hold fairly accurate. Ideal Gas Law[ edit ] Ideal gases can be completely described using the ideal gas law: [Ideal Gas Law] Real Gases[ edit ] All real gases (or non-ideal gases)

What is the ability of fluids to offer resistance to flow?

Characteristics of Fluids Characteristics of Fluids The principal difference in the mechanical behavior of fluids compared to solids is that when a shear stress is applied to a fluid it experiences a continuing and permanent distortion. Fluids offer no permanent resistance to shearing, and they have elastic properties only under direct compression: in contrast to solids which have all three elastic moduli, fluids possess a bulk modulus only. Thus, a fluid can be defined unambiguously as a material that deforms continuously and permanently under the application of a shearing stress, no matter how small. This definition does not address the issue of how fast the deformation occurs and as we shall see later this rate is dependent on many factors including the properties of the fluid itself. The inability of fluids to resist shearing stress gives them their characteristic ability to change shape or to flow; their inability to support tension stress is an engineering assumption, but it is a well-justified assumption because such stresses, which depend on intermolecular cohesion, are usually extremely small..... Because fluids cannot support shearing stresses, it does not follow that such stresses are nonexistent in fluids. During the flow of real fluids, the shearing stresses assume an important role, and their prediction is a vital part of engineering work. Without flow, however, shearing stresses cannot exist, and compression stress or pressure is the only stress to be considered (Elementary Fluid Mechanics, 7th edition, by R.L. Street, G.Z. Watters and J.K. Vennard, John Wiley \& Sons, 1996). So we see that the most obvious property of fluids, their ability to flow and change their shape, is precisely a result of their inability to support shearing stresses. Flow is possible without a shear stress, since differences in pressure will cause a fluid lump to experience a resultant force and produce an acceleration, but when a fluid is deforming its shape, shearing stresses must be present. With this definition of a fluid, we can recognize that certain materials that look like solids are actually fluids. Tar, for example, is sold in barrel-sized chunks which appear at first sight to be the solid phase of the liquid which forms when the tar is heated. However, cold tar is also a fluid. If a brick is placed on top of an open barrel of tar, we will see it very slowly settle into the tar. It will continue to settle as time goes by --- the tar continues to deform under the applied load --- and eventually the brick will be engulfed by the tar. Even then it will continue to move downwards until it reaches the bottom of the barrel. Glass is another substance that appears to be solid, but is actually a fluid. The glass flows under the action of its own weight. If you measure the thickness of a very old glass pane you would find it to be larger at the bottom than at the top of the pane. This deformation happens very slowly because the glass has a very high viscosity, and the results can take centuries to become obvious. Another example: silly putty behaves like an elastic body when subject to rapid stress (it bounces like a ball) but it has fluid behavior under a slowly acting stress (it flows like a fluid under its own weight).

What is described as an ionized gas with approximately equal numbers of positive and negative charges?

Plasma | Article about plasma by The Free Dictionary Plasma | Article about plasma by The Free Dictionary http://encyclopedia2.thefreedictionary.com/plasma Related to plasma: Plasma tv , Plasma Chemistry , Plasma display plasma, in physics, fully ionized gas of low density, containing approximately equal numbers of positive and negative ions (see electron electron, elementary particle carrying a unit charge of negative electricity. Ordinary electric current is the flow of electrons through a wire conductor (see electricity). The electron is one of the basic constituents of matter. ..... Click the link for more information.  and ion ion, atom or group of atoms having a net electric charge. Positive and Negative Electric Charges A neutral atom or group of atoms becomes an ion by gaining or losing one or more electrons or protons. ..... Click the link for more information. ). It is electrically conductive and is affected by magnetic fields. The study of plasma, called plasma physics, is especially important in research efforts to produce a controlled thermonuclear reaction (see nuclear energy nuclear energy, the energy stored in the nucleus of an atom and released through fission, fusion, or radioactivity. In these processes a small amount of mass is converted to energy according to the relationship E = mc2, where E is energy, m ..... Click the link for more information. ). Such a reaction requires extremely high temperatures; it has been computed that a temperature of about 10 million degrees Celsius would be needed to initiate the reaction between deuterium and tritium. By passing a very high electric current through plasma great heat is produced and, simultaneously, an electromagnetic field is created, causing the plasma to withdraw from the walls of its container. The contraction of the plasma, called the pinch effect, prevents the container from being destroyed, but the effect may become unstable too quickly for the fusion reaction. The properties of plasma are distinct from those of the ordinary states of matter states of matter, forms of matter differing in several properties because of differences in the motions and forces of the molecules (or atoms, ions, or elementary particles) of which they are composed. ..... Click the link for more information. , and for this reason many scientists consider plasma a fourth state of matter. Interstellar gases, as well as the matter inside stars, are thought to be in the form of plasma, thus making plasma a common form of matter in the universe. See also condensate condensate, matter in the form of a gas of atoms, molecules, or elementary particles that have been so chilled that their motion is virtually halted and as a consequence they lose their separate identities and merge into a single entity. ..... Click the link for more information. . Plasma (physics) The field of physics that studies highly ionized gases. Plasma is a gas of charged and neutral particles which exhibits collective behavior. All gases become ionized at sufficiently high temperatures, creating what has been called a fourth state of matter, together with solids, liquids, and gases. It has been estimated that more than 99% of the universe is in the plasma state. On the Earth, plasmas are much less common. Lightning is a familiar natural manifestation, and fluorescent lights are a practical application. Plasma applications and studies make use of an enormous range of plasma temperatures, densities, and neutral pressures. They extend from plasma processing applications at relatively low temperatures (such as plasma etching of semiconductor chips at low pressure, or plasma cutting torches at atmospheric pressure) to studies of controlled fusion at very high temperatures. Plasma physics is a many-body problem that can be described by a combination of Newton's laws and Maxwell's equations. The charged particles in plasmas are usually ions, both positive and negative, and electrons. Plasmas are normally quasineutral; that is, the net positive ion charge density approximately equals the net negative charge density e

What name is given to the very serious chain of events which can follow the failure of the cooling system in a nuclear reactor?

THE FEARSOME REACTOR MELTDOWN ACCIDENT next=> THE FEARSOME REACTOR MELTDOWN ACCIDENT Technologies are normally developed by entrepreneurs whose primary goal is making money. If the technology is successful, the entrepreneurs prosper as a new industry develops and thrives. In the process, the environmental impacts of this new technology are the least of their concerns. Only after the public revolts against the pollution inflicted upon it does the issue of the environment come into the picture. At that point an adversarial relationship may develop, with the government serving to protect the public at the expense of the industry. Coal-burning technologies have been an excellent example of this development process. With nuclear energy, everything was to be entirely different. It was conceived and brought into being by the world's greatest scientists. They banded together to obtain government support; the highly publicized letter from Albert Einstein to President Roosevelt in 1941 was a key element in that process. Their motivation was entirely idealistic. None of them thought about making money, and there was no mechanism for them to do so. Their first objective was to save the world from the hideous Hitler, and after World War II it was to protect freedom and democracy through military strength. But from the beginning of the project in the early 1940s, the scientists always felt strongly that this new technology, developed at government expense, would provide great benefits to mankind. Distinguished scientists like Henry Smythe and Glenn Seaborg held high positions of power all the way up until the early 1970s, and through them many of the greatest and most idealistic scientists, like Enrico Fermi, Eugene Wigner, and Hans Bethe, exerted great influence on the course of events. Directly or indirectly, hundreds of scientists were involved in guiding our national nuclear energy program. They set up national laboratories of unprecedented size in the New York (Brookhaven), Chicago (Argonne), and San Francisco (Berkeley, Livermore) areas and at the wartime development sites in Oak Ridge, Tennessee and Los Alamos, New Mexico. They arranged for an unprecedented level of financial support for research in universities where most of the scientists were based. Their objectives went far beyond development of nuclear technology, and included seeking a thorough understanding of the environmental effects. Their approach ran the gamut from the most basic research to the most practical applications. The government's side of this enterprise was run by the Atomic Energy Commission (AEC). The AEC was set up at the behest of scientists to remove nuclear energy development from military control. Prominent scientists served as commissioners, often as chairmen. It's General Advisory Committee, made up of some of the nation's most distinguished scientists, exerted very strong influence. The AEC was monitored by the Congressional Joint Committee on Atomic Energy, which included some of the most powerful senators and representatives. A spirit of close cooperation reigned throughout. The goal of all was to provide humankind with the blessings of nuclear energy as expeditiously as possible. There was a general understanding among all concerned that the scientists had paid their dues — they had given the government's military nuclear weapons, nuclear submarines, and a host of other goodies — and that their new technology was to serve humanity under the guidance of this research enterprise. Government also recognized that this enterprise, in the long run, would serve the public interest, and continues to support it to this day. A recent well-publicized element of that program is the multibillion dollar superconducting supercollider accelerator to be constructed in Texas to study the fundamental nature of matter, with no practical applications in sight. Use of nuclear energy to generate electricity was a very important part of this research and development program. In order to promot

Which electronic device magnifies the strength of a signal?

Audio and sound engineer's glossary of terms. | Testing1212   Absorption Short for the term Acoustical Absorption (quality of a surface or substance to take in, not reflect, a sound wave). AC 1)  Abbreviation for alternating current. 2)  An abbreviation of the term Alternating Current (electric current which flows back and forth in a circuit; all studio signals running through audio lines are AC). Acoustic/Acoustical Having to do with sound that can be heard by the ears. AcousticsThe behaviour of sound and its study. The acoustics of a room depend on its size and shape and the amount and position of sound-absorbing and reflecting material. Acoustic Amplifier The portion of the instrument which makes the vibrating source move more air or move air more efficiently; this makes the sound of the instrument louder. Examples of acoustic amplifiers include: 1) The body of an acoustic guitar, 2) The sounding board of a piano, 3) The bell of a horn and 4) The shell of a drum. Acoustic Echo Chamber A room designed with very hard, non-parallel surfaces and equipped with a speaker and microphone; dry signals from the console are fed to the speaker and the microphone will have a reverberation of these signals that can be mixed in with the dry signals at the console. Action In guitar playing, action refers to how far the strings sit off of the guitar neck. When strings are close to the neck, it is referred to as “Low Action”. When the string sit far above the neck, it is called “High Action”. Guitars with low action are easier to play, but make sure they are not too close, or it could causing buzzing. Active Crossover Uses active devices (transistors, IC’s, tubes) and some form of power supply to operate. Active/Inactive Microphones Scientific definitions aside, active microphones generally sound better than inactive ones, but they generally cost more. They also require the use of either a battery or phantom power while inactive mics need only be plugged into the mic cord in order to work. In most playing situations, the subtle improvement in sound quality from an active mic isn’t worth the extra cost and hassle. One possible exception it the headset mic. Put simply, inactive headset mics just plain suck. Active headset mics put out a much stronger signal and feed back much less. A/D An abbreviation of Analog to Digital Conversion (the conversion of a quantity that has continuous changes into numbers that approximate those changes), or Analog to Digital Converter. ADAT A trademark of Alesis Corporation designating its modular digital multitrack recording system released in early 1993. ADSR The letters A, D, S &R are the first letters of: Attack, Decay, Sustain and Release. These are the various elements of volume changes in the sounding of a keyboard instrument. AES An abbreviation of Audio Engineering Society. AES/EBU Professional Interface A standard for sending and receiving digital audio adopted by the Audio Engineering Society and the European Broadcast Union. Aliasing A sampler mis-recognizing a signal sent to it that is at a frequency higher than the Nyquist Frequency. Upon playback, the system will provide a signal at an incorrect frequency (called an alias frequency). Aliasing is a kind of distortion. Alternating Current Electric current which flows back and forth in a circuit. Ambience The portion of the sound that comes from the surrounding environment rather than directly from the sound source. Ambient Field A term with the same meaning as the term Reverberant Field (the area away from the sound source where the reverberation is louder than the direct sound). Ambient Micing Placing a microphone in the reverberant field (where the reverberation is louder than the direct sound) so as to do a separate recording of the ambience or to allow the recording engineer to change the mix of direct to reverberant sound in recording. Amp 1) An abbreviation of the term Amplifier (A device which increases the level of an electrical signal. 2) An abbreviation of Ampere (the unit of current). 3) An abbreviation of amplitude (the height of a

What was the name of the unit of heat now replaced by the joule?

Units of Heat - <i>BTU, Calorie and Joule</i> The most common units for heat are BTU (Btu) - British Thermal Unit - also known as a "heat unit" in United States Calorie BTU - British Thermal Unit The unit of heat in the imperial system - the BTU - is the amount of heat required to raise the temperature of one pound of water through 1oF (58.5oF - 59.5oF) at sea level (30 inches of mercury). 1 Btu (British thermal unit) = 1055.06 J = 107.6 kpm = 2.931 10-4 kWh = 0.252 kcal = 778.16 ft.lbf = 1.0551010 ergs = 252 cal = 0.293 watt-hours An item using one kilowatt-hour of electricity generates 3412 Btu. one hundred thousand (105) Btu are called a therm Calorie A calorie is commonly defined as the amount of heat required to raise the temperature of one gram of water 1oC the kilogram calorie, large calorie, food calorie, Calorie (capital C) or just calorie (lowercase c) is the amount of energy required to raise the temperature of one kilogram of water by one degree Celsius 1 calorie (cal) = 1/860 international watthour (Wh) 1 kcal = 4186.8 J = 426.9 kp m = 1.163 10-3 kWh = 3.088 ft lbf = 3.9683 Btu = 1000 cal Be aware that alternative definitions exists - in short:  Thermochemical calorie   International Steam Table calorie (1929) International Steam Table calorie (1956) IUNS calorie (Committee on Nomenclature of the International Union of Nutritional Sciences) The calorie is outdated and commonly replaced by the SI-unit Joule. Joule The unit of heat in the SI-system the Joule is a unit of energy equal to the work done when a force of one newton acts through a distance of one meter 4.184 joule of heat energy (or one calorie) is required to raise the temperature of a unit weight (1 g) of water from 0oC to 1oC, or from 32oF to 33.8oF 1 J (Joule) = 0.1020 kpm = 2.778 10-7 kWh = 2.389 10-4 kcal = 0.7376 ft.lbf = 1 kg.m2/s2 = 1 watt second = 1 Nm = 9.478 10-4 Btu Heating - Heating systems - capacity and design of boilers, pipelines, heat exchangers, expansion systems and more Thermodynamics - Effects of work, heat and energy on systems Sponsored Links Heat Storage in Materials - Energy stored as sensible heat in materials Specific Heat of common Substances - Specific heat of materials like wet mud, granite, sandy clay, quartz sand and more Gases - Ratios of Specific Heat - Ratios of specific heat for gases in constant pressure and volume processes Heat, Work and Energy - Heat, work and energy tutorial - essentials as specific heat Specific Heat - Specific Heat is the amount of heat required to change a unit mass of a substance by one degree in temperature Sponsored Links en: heat units btu calorie joule es: unidades de calor por efecto Joule calorías btu de: Wärmeeinheiten btu Kalorien Joule Search the Engineering ToolBox

What does c represent in the equation e = mc*2?

What is the significance of E = mc2? And what does it mean? - Scientific American Scientific American Advertisement | Report Ad Ronald C. Lasky, director of the Cook Engineering Design Center at Dartmouth College, explains the significance behind this hallowed equation: It is the most famous equation in the world. Many can recite it—and attribute it to Albert Einstein—but few know its significance. It tells us that mass and energy are related, and, in those rare instances where mass is converted totally into energy, how much energy that will be. The elegance with which it ties together three disparate parts of nature—energy, the speed of light and mass—is profound. Here is where the equation of all equations comes from: It was known for some time before Einstein's insights that electromagnetic radiation (light, for example) possessed momentum. This quality of radiation is small in magnitude—after all, you needn't worry about being knocked over by sunlight—but easily measurable. Applying an understanding of light's momentum within a little thought experiment, it is possible to see how E = mc2 comes about. Consider a cubic hollow box at rest in space with sides of length D and a mass of M. This box is also symmetrical in its mass distribution. One of the faces inside the box is coated with a fluorescing material, and, at a given moment, a photon (i.e., a particle of light) is emitted from that material, perpendicular to its surface. The momentum of this photon causes the box to move in the opposite direction as the photon, and it continues to move until the photon hits the opposite wall. During this time the box moves a very small distance, Δx. Image: RONALD LASKY Newton's laws of mechanics tell us that the center of mass cannot move, because the box has not been acted upon by an outside force. However, in order to keep the center of mass constant, since the box has moved, some mass must have been transferred from the fluorescing side of the box to the absorbing side in the process of generating the photon and its striking the opposite side. Therefore the photon must have a mass, m. So the photon, which also possesses energy E, is emitted from the fluorescing side of the box. Its momentum, Pphoton, is equal to its energy divided by the speed of light: Pphoton = E / c. The photon will impart this momentum to the box, causing the box to move a small distance, Δx, during the time, t, in which the photon travels to the opposite side of the box. The momentum of the box, Pbox, is also equal to its mass, M, times the velocity, vbox, at which it moves before the photon strikes its target. (Note: The box loses the photon's mass, m, during this process, but this slight loss can be neglected here.) Hence: Pphoton = Pbox = E / c = Mvbox Then vbox = E / cM (1) We can also determine the time it takes for the photon to travel across the box: it is equal to the length, between parallel faces, of the box (which is D), minus the amount the box moved in the opposite direction (Δx), divided by the speed of light, c. (The target will essentially have moved a slight distance closer, meaning the photon did not have to travel the full distance D.): t = (D - Δx) / c

What is a cylindrical coil of wire in which a magnetic field is created when an electric current is passed though it?

electromagnetism - Why does electricity flowing through a copper coil generate a magnetic field? - Physics Stack Exchange Why does electricity flowing through a copper coil generate a magnetic field? up vote 4 down vote favorite Can some one please explain to me why electricity flowing though a copper coil generates a magnetic field or where I could possibly find that information? Are there other materials that produce a magnetic field when a current is run through them in a different shape? Thanks! up vote 4 down vote accepted Can some one please explain to me why electricity flowing though a copper coil generates a magnetic field or where I could possibly find that information? An electric current (a flow of electric charge) has an associated magnetic field regardless of the material (or space) the flow occurs in. This is a fundamental part of electromagnetism, rooted in observation, and quantified in Ampere's Law . I which to emphasize that this phenomenon is considered to be fundamental in nature, which means, there cannot be a "more" fundamental explanation (for, if there were, electromagnetism would not be fundamental). up vote 3 down vote This is a very-basic question. There are lot more things to digest than just that in EM..! All because of Maxwell equations ... Both Electric & Magnetic fields are inter-dependent (i.e.) One field requires another (or) one field produces another. The phenomenon is called Electromagnetism . For example, consider an electric charge at rest (static). It produces an electric field. But when the charge is in motion (current), a magnetic field is produced perpendicular to its direction of propagation. Say, If you pass current through a straight wire, magnetic field is formed around the wire in the form of circular rings (could affect compass or metal fillings nearby). On the other hand, you're passing current through a circular spring-like thing (commonly, a coil) called solenoid, magnetic field is produced along its axis. Simply you could keep in mind that Magnetic field is produced by moving charges (current). This is an observed phenomena and it's explained by Maxwell. Your last question is "Ok to ask"... Yes, there are a lot of materials (mostly metals) that produce magnetic field when current flows through them. But, Shape is not at all "a matter". It's whether there's a change in the fields that matters...

Whose 'unified field theory' tried to explain the four fundamental forces in terms of a single, unified force?

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Unified Field Theory Unified Field Theory, in physics, a theory that proposes to unify the four known interactions, or forces�the strong, electromagnetic, weak, and gravitational forces�by a simple set of general laws. Four distinct forces are known to control all the observed interactions in matter: gravitation, electromagnetism, the strong force (a short-range force that holds atomic nuclei together), and the weak force (the force responsible for slow nuclear processes, such as beta decay). The attempts to develop a unified field theory are grounded in the belief that all physical phenomena should ultimately be explainable by some underlying unity. One of the first to attempt the development of such a theory was Albert Einstein, whose work in relativity had led him to the hypothesis that it should be possible to find a unifying theory for the electromagnetic and gravitational forces. Einstein tried unsuccessfully during the last 30 years of his life to develop a theory that would represent forces and material particles by fields only, in which particles would be regions of very high field intensity. The development of quantum theory, which Einstein rejected, and the discovery of many new particles, however, precluded Einstein's success in formulating a unifying theory based on relativity and classical physics alone. An important advance in this quest was made in 1967-68 by the American physicist Steven Weinberg and the Pakistani physicist Abdus Salam. They succeeded in unifying the weak interaction and the el

What diverges rays of light, if it is concave?

Ray Diagrams - Concave Mirrors Reflection and the Ray Model of Light - Lesson 3 - Concave Mirrors Ray Diagrams - Concave Mirrors Spherical Aberration The theme of this unit has been that we see an object because light from the object travels to our eyes as we sight along a line at the object. Similarly, we see an image of an object because light from the object reflects off a mirror and travel to our eyes as we sight at the image location of the object. From these two basic premises, we have defined the image location as the location in space where light appears to diverge from. Ray diagrams have been a valuable tool for determining the path taken by light from the object to the mirror to our eyes. In this section of Lesson 3, we will investigate the method for drawing ray diagrams for objects placed at various locations in front of a concave mirror. To draw these diagrams, we will have to recall the two rules of reflection for concave mirrors: Any incident ray traveling parallel to the principal axis on the way to the mirror will pass through the focal point upon reflection. Any incident ray passing through the focal point on the way to the mirror will travel parallel to the principal axis upon reflection. Earlier in this lesson, the following diagram was shown to illustrate the path of light from an object to mirror to an eye. In this diagram five incident rays are drawn along with their corresponding reflected rays. Each ray intersects at the image location and then diverges to the eye of an observer. Every observer would observe the same image location and every light ray would follow the law of reflection. Yet only two of these rays would be needed to determine the image location since it only requires two rays to find the intersection point. Of the five incident rays drawn, two of them correspond to the incident rays described by our two rules of reflection for concave mirrors. Because they are the easiest and most predictable pair of rays to draw, these will be the two rays used through the remainder of this lesson   Step-by-Step Method for Drawing Ray Diagrams The method for drawing ray diagrams for concave mirror is described below. The method is applied to the task of drawing a ray diagram for an object located beyond the center of curvature (C) of a concave mirror. Yet the same method works for drawing a ray diagram for any object location. 1. Pick a point on the top of the object and draw two incident rays traveling towards the mirror. Using a straight edge, accurately draw one ray so that it passes exactly through the focal point on the way to the mirror. Draw the second ray such that it travels exactly parallel to the principal axis. Place arrowheads upon the rays to indicate their direction of travel.     2. Once these incident rays strike the mirror, reflect them according to the two rules of reflection for concave mirrors. The ray that passes through the focal point on the way to the mirror will reflect and travel parallel to the principal axis. Use a straight edge to accurately draw its path. The ray that traveled parallel to the principal axis on the way to the mirror will reflect and travel through the focal point. Place arrowheads upon the rays to indicate their direction of travel. Extend the rays past their point of intersection.   3. Mark the image of the top of the object. The image point of the top of the object is the point where the two reflected rays intersect. If your were to draw a third pair of incident and reflected rays, then the third reflected ray would also pass through this point. This is merely the point where all light from the top of the object would intersect upon reflecting off the mirror. Of course, the rest of the object has an image as well and it can be found by applying the same three steps to another chosen point. (See note below .)     4. Repeat the process for the bottom of the object. The goal of a ray diagram is to determine the location, size, orientation, and type of image that is formed by the concave mirror. Typically, this requires determining where the image of t

What can be expressed as the number of cycles of a vibration occurring per unit of time?

Frequency - definition of frequency by The Free Dictionary Frequency - definition of frequency by The Free Dictionary http://www.thefreedictionary.com/frequency n. pl. fre·quen·cies 1. The property or condition of occurring at frequent intervals. 2. Mathematics & Physics The number of times a specified periodic phenomenon occurs within a specified interval, as: a. The number of repetitions of a complete sequence of values of a periodic function per unit variation of an independent variable. b. The number of complete cycles of a periodic process occurring per unit time. c. The number of repetitions per unit time of a complete waveform, as of an electric current. 3. Statistics [Latin frequentia, multitude, from frequēns, frequent-, crowded, numerous, frequent.] frequency n, pl -cies 1. the state of being frequent; frequent occurrence 2. the number of times that an event occurs within a given period; rate of recurrence 3. (Mathematics) physics the number of times that a periodic function or vibration repeats itself in a specified time, often 1 second. It is usually measured in hertz. Symbol: ν or f 4. (Statistics) statistics a. the number of individuals in a class (absolute frequency) b. the ratio of this number to the total number of individuals under survey (relative frequency) 5. (Biology) ecology a. the number of individuals of a species within a given area b. the percentage of quadrats that contains individuals of a species Also called (for senses 1, 2): frequence [C16: from Latin frequentia a large gathering, from frequēns numerous, crowded] fre•quen•cy 1. Also, fre′quence. the state or fact of being frequent; frequent occurrence. 2. rate of occurrence. 3. Physics. a. the number of periods or regularly occurring events of any given kind in a unit of time, usu. one second. b. the number of cycles or completed alternations per unit time of a wave or oscillation. Symbol: F; Abbr.: freq. 4. Math. the number of times a value recurs in a unit change of the independent variable of a given function. 5. Statistics. the number of items occurring in a given category. [1545–55; < Latin] fre·quen·cy (frē′kwən-sē) 1. Physics The number of complete cycles of a wave, such as a radio wave, that occur per second. See more at wave . 2. Mathematics The ratio of the number of occurrences of some event to the number of opportunities for its occurrence. Frequency (See also DURATION , TIME .) once in a blue moon Very rarely. A blue moon occurs when there is a full moon twice in the same month, an unusual event, but one that takes place from time to time. rare as hen’s teeth See scarce as hen’s teeth, ABSENCE . when two Fridays come together Never. Since two Fridays never come together, this expression is usually used as a sarcastic quip when one is asked when he intends to do something of an onerous nature such as complete a project, pay back a personal loan, or the like. frequency Number of cycles or waves per second. ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1. frequency - the number of occurrences within a given time period; "the frequency of modulation was 40 cycles per second"; "the frequency of his seizures increased as he grew older" audio frequency , audio - an audible acoustic wave frequency radio frequency - an electromagnetic wave frequency between audio and infrared infrared , infrared frequency - the infrared region of the electromagnetic spectrum; electromagnetic wave frequencies below the visible range; "they could sense radiation in the infrared" wave number - the reciprocal of the wavelength of a wave attendance - the frequency with which a person is present; "a student's attendance is an important factor in her grade" count per minute , counts/minute - frequency per minute sampling frequency - (telecommunication) the frequency of sampling a continuously varying signal rate - a magnitude or frequency relative to a time unit; "they traveled at a rate of 55 miles per hour"; "the rate of change was faster than expected" 2. frequency - the ratio of the number of observations in a statistical category to the total number

What is the product of the mass of a body and its linear velocity?

What is the difference between force (F=MA) and momentum (mass * velocity)? - Quora Quora Written May 2, 2015 Formula wise, you just said it. By definition, momentum refers to the quantity of motion that an object has. And the rate of change of that momentum is defined as the force. Written May 6, 2015 Force and momentum are two concepts that are used in mechanics to describe statics or dynamics of bodies. Both force and momentum are vectors.  Force is an external cause, while momentum is an internal property of matter. A force is required to change the momentum of any object. The force on an object can be defined as the change of momentum per unit time.  The definition of force is “any influence that causes or attempts to cause a free body to undergo a change in the acceleration or the shape of the body.” There are two main types of forces  - contact forces and field forces. Contact forces are forces that are used in everyday incidents such as pushing or pulling an object. Field forces include gravitational force, magnetic force, and electric force. Forces such as static friction, surface tension, and reactive forces are all responsible for keeping the objects in static conditions. Forces such as gravitational force, electrical force, and magnetic force are all responsible for keeping the world and everything in the universe together. Momentum is a measurement of the inertia of an object. It is divided into two main types. One is the linear momentum, and the other is the angular momentum. Linear momentum is defined as the product of the mass and velocity of the object. Angular momentum is defined as the product of moment of inertia and angular velocity of the object. Both these are measurements of the current inertia of the system. Angular momentum is related to the rotation or revolution of matter. It is, in effect, a measure of the quantity of rotation of a system of matter, taking into account its mass, rotations, motions and shape.  Linear momentum is also a conserved quantity, meaning that if a closed system is not affected by external forces, its total linear momentum cannot change. This fact, known as the law of conservation of momentum, is implied by Newton's Laws of Motion. A change of momentum always requires a net force or torque acting upon the object. Momentum is a relativistic variant. Written Feb 17, 2016 Momentum measures the 'motion content' of an object, and is based on the product of an object's mass and velocity. Momentum doubles, for example, when velocity doubles. Similarly, if two objects are moving with the same velocity, one with twice the mass of the other also has twice the momentum. Force, on the other hand, is the push or pull that is applied to an object to CHANGE its momentum. Newton's second law of motion defines force as the product of mass times ACCELERATION (vs. velocity). Since acceleration is the change in velocity divided by time, you can connect the two concepts with the following relationship: force = mass x (velocity / time) = (mass x velocity) / time = momentum / time Multiplying both sides of this equation by time: force x time = momentum

Which quantity has direction as well as magnitude?

How does change of direction change the velocity? - Quora Quora Written May 10, 2016 Velocity is a vector quantity. It has both magnitude as well as direction. When we say that velicity changes, there can be three conditions: Only the magnitude  changes (what we call speed) and direction remains the same. Eg. A car moving on a straight road applies breaks. Only the direction changes and the magnitude remains constant. Eg. A car moves on a circular path with constant speed. Both the direction and the magnitude changes. Eg. A car moving along a curved path with some tangential acceleration. 367 Views Related Questions

What is the SI unit of magnetic flux density, named after a Croatian electrical engineer?

Enter a value into either text box and select units using the drop-down boxes. = What is Magnetic Flux Density? Magnetic flux density is the amount of magnetic flux per unit area of a section that is perpendicular to the direction of flux. It is also sometimes known as "magnetic induction" or simply "magnetic field". It can be thought of as the density of the magnetic field lines - the closer they are together, the higher the magnetic flux density. Mathematically it is represented as B = Φ/A where B is magnetic flux density in teslas (T), Φ is magnetic flux in webers (Wb), and A is area in square meters (m2). The SI unit for magnetic flux density is the tesla which is equivalent to webers per square meter. The unit was named in 1960 after the Serbian-American electrical engineer Nikola Tesla. Bookmark this page in your browser using Ctrl and d or using one of these services: (opens in new window)

What is studied in the science of cryogenics?

Cryogenics - humans, body, used, process, Earth, form, energy, methods, gas Cryogenics Cryogenics Photo by: deepspacedave Cryogenics is the science of producing and studying low-temperature conditions. The word cryogenics comes from the Greek word cryos , meaning "cold," combined with a shortened form of the English verb "to generate." It has come to mean the generation of temperatures well below those of normal human experience. More specifically, a low-temperature environment is termed a cryogenic environment when the temperature range is below the point at which permanent gases begin to liquefy. Permanent gases are elements that normally exist in the gaseous state and were once believed impossible to liquefy. Among others, they include oxygen, nitrogen, hydrogen, and helium. The origin of cryogenics as a scientific discipline coincided with the discovery by nineteenth-century scientists that the permanent gases can be liquefied at exceedingly low temperatures. Consequently, the term "cryogenic" applies to temperatures from approximately −100°C (−148°F) down to absolute zero (the coldest point a material could reach). The temperature of any material—solid, liquid, or gas—is a measure of the energy it contains. That energy is due to various forms of motion among the atoms or molecules of which the material is made. A gas that consists of very rapidly moving molecules, for example, has a higher temperature than one with molecules that are moving more slowly. In 1848, English physicist William Thomson (later known as Lord Kelvin; 1824–1907) pointed out the possibility of having a material in which particles had ceased all forms of motion. The absence of all forms of motion would result in a complete absence of heat and temperature. Thomson defined that condition as absolute zero. Words to Know Absolute zero: The lowest temperature possible at which all molecular motion ceases. It is equal to −273°C (−459°F). Kelvin temperature scale: A temperature scale based on absolute zero with a unit, called the kelvin, having the same size as a Celsius degree. Superconductivity: The ability of a material to conduct electricity without resistance. An electrical current in a superconductive ring will flow indefinitely if a low temperature (about −260°C) is maintained. Thomson's discovery became the basis of a temperature scale based on absolute zero as the lowest possible point. That scale has units the same size as the Celsius temperature scale but called kelvin units (abbreviation K). Absolute zero is represented as 0 K, where the term degree is omitted and is read as zero kelvin. The Celsius equivalent of 0 K is −273°C, and the Fahrenheit equivalent is −459°F. One can convert between Celsius and Kelvin scales by one of the following equations: °C = K − 273 or K = °C + 273 Cryogenics, then, deals with producing and maintaining environments at temperatures below about 173 K. One aspect of cryogenics involves the development of methods for producing and maintaining very low temperatures. Another aspect includes the study of the properties of materials at cryogenic temperatures. The mechanical and electrical properties of many materials change very dramatically when cooled to 100 K or lower. For example, rubber, most plastics, and some metals become exceedingly brittle. Also many metals and ceramics lose all resistance to the flow of electricity, a phenomenon called superconductivity. In addition, helium that is cooled to very nearly absolute zero (2.2 K) changes to a state known as superfluidity. In this state, helium can flow through exceedingly narrow passages with no friction. History Cryogenics developed in the nineteenth century as a result of efforts by scientists to liquefy the permanent gases. One of the most successful of these scientists was English physicist Michael Fa

What is the favorite food of the giant panda?

Bamboo and Panda Bears Bamboo, Favorite Food of Pandas   Bamboo is the favorite food of Giant Panda bears. It is grown all over the Panda's habitat. But it also can and is grown in many other parts of the world. In th U.S., many varieties have been imported and flourish in home gardens. They are popular in home gardens where Japanese or asian setting are desired. For others, they just like the challenge of growing something different. Bamboo Trivia: An adult Giant Panda eats 45 pounds of bamboo per day. Bamboo can be grown in most climates. It also requires little care and attention, thriving and spreading profusely through it's root system . It is strongly recommended that gardeners create a barrier two to three feet deep around the planting area to contain the spread of the roots to areas beyond where the plants are desired. Not only is bamboo grown as an ornamental plant, but the shoots are edible. If you eat a variety of chinese food, chances are you have eaten bamboo. Like rice, it has little flavor of it's own and takes on the flavor of the food it is cooked with. While nutritional value is low, it is a good source of fiber. Low nutritional value is one reason Giant Pandas need to eat so much of it. Bamboo shoots command a fairly high market price so it can make a good cash crop. Bamboo makes great gifts. It is a sign of luck. It is a sign of love. Put it all together on Valentine's Day and you are "lucky in love". For a nice selection for Valentine's Day, other events, or just for you. Did You Know? Bamboo leaves are poisonous. So, think twice about planting if you have young children. More Information:

What kind of an animal is a marmoset?

Environmental Enrichment for Marmosets | Animal Welfare Institute Environmental Enrichment for Marmosets Universities Federation for Animal Welfare  The Old School, Brewhouse Hill,  Wheathampstead, Herts AL4 8AN INTRODUCTION Marmosets and tamarins are small (250-500 g) South American monkeys of the family Callitrichidae. They are forest living species with squirrel-like locomotion and, unlike typical monkeys, most of the digits have claws instead of nails. They live in small troops, most members of which are closely related; there is one breeding female and usually several other adult non-breeding females. There is some controversy among field workers as to whether they are monogamous or polyandrous (several males mating one female). The single breeding female has been observed, in the wild, to mate with several males in the troop, but it is not known whether matings with males other than the dominant proved fertile.  The natural food of marmosets and tamarins consists of fruits, nectar, shoots and insects, young birds and bird's eggs. The animal protein intake is high. The short tusked marmosets (Callithrix and Cebuella) feed extensively on the gum produced by some species of forest tree which they access by gouging with a scoop formed by the lower incisors and shortened canine teeth. The tamarins (Saguinus and Leontopithecus) do not gouge but may feed opportunistically on gum oozing from wounds on trees. Field studies have shown that callitrichids spend up to 60 per cent of their time actively foraging.  Unlike other monkeys, marmosets give birth to two or more young in a litter. Parental care, which includes carrying, grooming and sharing food with infants, is undertaken by all adult and adolescent members of the troop.  The potentiality for using marmosets as breeding animals for biomedical research is well recognised and there are now numerous laboratory breeding colonies. Where the marmoset is a suitable model, its small size and high reproductive capacity have proved valuable assets, and the common marmoset is the only species of monkey used in the laboratory where supply is totally independent of wild caught stock.  There are of course some disadvantages to the marmoset, it is monogamous under captive conditions, so that equal numbers of males and females have to be kept in the breeding colony. Although marmosets are rarely capable of rearing more than two young, in over 60 per cent of captive births more than two young are born; in the case of triplets, supplementary feeding or hand rearing may be used to promote the survival of all three young. While triplets are commonest, females have been known to give birth to as many as five infants. Where there are four or five in a litter, however, they are usually undersized and fail to thrive. In indoor facilities the diet must be supplemented with vitamin D3 or an ultra-violet light source be provided.  These facts will probably be familiar but they form an essential background to any discussion of environmental enrichment in marmosets.  THE NEED FOR ENVIRONMENTAL ENRICHMENT  Many mammals, and probably some of the more intelligent birds, are known to suffer if their environment is too restricted. The evidence that their behavioural needs are not being met is based on the occurrence of abnormal behaviour in the form of inactivity, apathy or stereotyped behaviours such as pacing or running around in circles.6 These symptoms are most pronounced where primates are housed singly and the emotional state of the animal can best be described as boredom.  In nature, a marmoset leads a busy and varied life; it is adapted to a complex environment and foraging alone is elaborate and involves the selection of seasonally varying vegetable food items and hunting insect prey. Survival depends on skill and ingenuity and constant vigilance to identify aerial, arboreal and ground predators, which may be mobbed. Marmosets have a wide repertoire of vocalisations which they use to convey messages both within and between troops.  The commonly used metal laboratory cage 0.5 x 0.5 x 0.8 m with

Which plant has flowers but no proper leaves?

Learn How To Care for House Plants | Teleflora AFRICAN VIOLET plant care A healthy African violet will bloom for nine months and then rest for three. Despite their delicate appearance, they are not difficult to care for. Keep their soil moist to dry and allow it to dry out between waterings to encourage blooming. Because water can damage their leaves, always water them from the bottom by placing the container in a tray of water. Allow the plant to absorb the water for about 30 minutes. Place your African violet in moderate to bright, indirect light, and avoid exposing them to sudden temperature changes. Pinch off wilted blossoms and leaves to encourage blooming, and fertilize monthly or when the plant is actively growing new leaves and buds. Shop for Blooming Plants AGLAONEMA "Chinese Evergreen" plant care Aglaonema, also known as Chinese evergreen, are very tolerant plants that do well in a range of environments. They prefer medium to low light in a warm room with slightly higher humidity, but they'll adapt to a spot that's slightly dryer and brighter (they make nice plants for the bedroom or bathroom). Allow their soil to dry out a bit between waterings (though, avoid letting it become bone dry), and gently clean off their leaves on a regular basis. Aglaonema, also known as Chinese evergreen, are very tolerant plants that do well in a range of environments. They prefer medium to low light in a warm room with slightly higher humidity, but they'll adapt to a spot that's slightly dryer and brighter (they make nice plants for the bedroom or bathroom). Allow their soil to dry out a bit between waterings (though, avoid letting it become bone dry), and gently clean off their leaves on a regular basis. AMARYLLIS plant care The amaryllis is native to warmer climates. The showy funnel-shaped blossoms stand atop a single stalk stem. Occasionally the flowers' weight will require some support for the stem. A simple bamboo stake and raffia tie can support the stem and be a decorative addition to the plant. Some amaryllis are frequently given as a gift in bulb form. Place your amaryllis in a bright, warm room at first, but when buds appear and begin to color, move it to a cooler spot to prolong blooming time. Water it moderately, keeping the soil moist but not soggy, and avoid letting it sit in water. Once it stops flowering, continue to give your amaryllis four hours of full sunlight so allow the leaves to collect solar energy to nourish the next year's blooms. Cut off the flowers once they fade, and cut down the stems to their base when they wither. Be sure to water and care for it as long as it has leaves, then let the leaves wilt naturally (but don't remove them). Keep the dormant bulb in its pot in a cool, dry place, and then replace the top inch or two of soil and start watering it when it begins to sprout again. ARECA PALM plant care Areca palms are generally hardy plants and prefer medium to bright light. Keep their soil moist but not soggy. If you allow the soil to become too dry, areca palms wilt dramatically, but it's easy to revive them with just a little water (though some of their fronds may turn yellow). Trim back palm fronds that become damaged or turn brown. AZALEA plant care Azaleas prefer cool, well-lit spots (out of direct sunlight) with temperatures between 60-65 degrees Fahrenheit. Check the soil frequently, and keep it moist but not soggy; never allow it to dry out completely. Allow new growth to develop, and regularly remove any dead flowers. When it's finished flowering, you can replant your azalea in a larger container or move it outdoors, as long as there's no risk of frost. Some cultivated varieties of azaleas are designed for inside use only. Others are "hardy" varieties that can be planted in the garden in warmer climates. Be sure to ask your florist what type of azaleas they carry. BONSAI plant care Display your bonsai in a spot that gets a good amount of bright, indirect light. Keep its soil moist to dry, watering it every 2-3 days from the bottom by submerging its planter in water (just to the top of

What name is given to animals that eat both flesh and plant material?

What are some animals that eat meat and plants? | Reference.com What are some animals that eat meat and plants? A: Quick Answer Animals that eat meat and plants are called omnivores, of which humans are a prime example. Some other animals that are omnivores are bears, skunks, squirrels and red foxes. Full Answer Some reptiles, fish and insects also feed on plants and animals. For instance, the opaleye fish eat both seaweed and the small organisms that live in the seaweed. Box turtles feed on flowers and berries as well as fish and frogs. Ants are opportunistic eaters, feeding on nectar and seeds when possible and other insects if the opportunity arises. Racoons, another example of an omnivore, display characteristics of both carnivores and herbivores. They have sharp teeth for ripping flesh and flat molars for grinding up plants. Omnivores are readily adaptable animals, allowing them to live in extreme conditions. If meat is not available, omnivores can live on plants and vice versa. This is because omnivores can digest both protein and fiber, while carnivores receive no nutritional value from plant material. Omnivores, along with carnivores, are part of the third trophic level. The first trophic level, which includes most plants, are called autotrophs because they produce their own food. The second trophic level includes herbivores, which eat autotrophs. Species in the third trophic level rely on organisms in the second trophic level for food completely or partially.

Which flightless marine birds of the southern hemisphere live in rookeries?

Penguin Facts: Species & Habitat Penguin Facts: Species & Habitat By Alina Bradford, Live Science Contributor | September 22, 2014 04:30pm ET MORE Credit: Dr. Robert Ricker, NOAA/NOS/ORR Penguins are torpedo-shaped, flightless birds that live in the southern regions of the Earth. Though many people imagine a small, black-and-white animal when they think of penguins, these birds actually come in a variety of sizes, and some are very colorful. For example, crested penguins sport a crown of yellow feathers. Blushes of orange and yellow mark the necks of emperor and king penguins. What look like bright yellow, bushy eyebrows adorn the heads of some species, such as the Fiordland, royal, Snares and rockhopper penguins. The macaroni penguin's name comes from the crest of yellow feathers on its head, which looks like the 18th-century hats of the same name. A light yellow mask covers the face of the yellow-eyed penguin around the eyes. An Adélie penguin on Penguin Island, which forms part of the South Shetland Islands of Antarctica. Credit: Gemma Clucas According to the Integrated Taxonomic Information System (ITIS), there are 19 species of penguin. (Some experts, however, say the eastern rockhopper is a subspecies of the southern rockhopper.) [ Gallery: Photos of 18 Penguin Species ] The smallest penguin species is the little (also called little blue) penguin. These birds grow to 10 to 12 inches (25.4 to 30.48 centimeters) tall and weigh only 2 to 3 lbs. (0.90 to 1.36 kilograms). The largest penguin is the emperor penguin. It grows to 36 to 44 inches (91.44 to 111.76 cm) tall and weighs 60 to 90 lbs (27.21 to 40.82 kg). Where do penguins live? Considered marine birds, penguins live up to 80 percent of their lives in the ocean, according to the New England Aquarium . All penguins live in the Southern Hemisphere, though it is a common myth that they all live in Antarctica. In fact, penguins can be found on every continent in the Southern Hemisphere. It is also a myth that penguins can only live in cold climates. The Galapagos penguin, for example, lives on tropical islands at the equator. What do penguins eat? Penguins are carnivores; they eat only meat. Their diet includes krill (tiny crustaceans), squid and fish. Some species of penguin can make a large dent in an area's food supply. For example, the breeding population of Adélie penguins (about 2,370,000 pairs) can consume up to 1.5 million metric tons (1.5 billion kg) of krill, 115,000 metric tons (115 million kg) of fish and 3,500 metric tons (3.5 million kg) of squid each year, according to Sea World . The yellow-eyed penguin is very tenacious when foraging for food. It will dive as deep as 120 meters (393.70 feet) up to 200 times a day looking for fish, according to the Yellow-Eyed Penguin Trust . Mating & baby penguins A group of penguins is called a colony, according to the U.S. Geological Survey. During breeding season, penguins come ashore to form huge colonies called rookeries, according to Sea World. Most penguins are monogamous. This means that male and female pairs will mate exclusively with each other for the duration of mating season. In many cases, the male and female will continue to mate with each other for most of their lives. For example, research has found that chinstrap penguins re-paired with the same partner 82 percent of the time and gentoo penguins re-paired 90 percent of the time. At around three to eight years old, a penguin is mature enough to mate. Most species breed during the spring and summer. The male usually starts the mating ritual and will pick out a nice nesting site before he approaches a female. After mating, the female emperor or king penguin will lay a single egg. All other species of penguins lay two eggs. The two parents will take turns holding the eggs between their legs for warmth in a nest. The one exception is the emperor penguin . The female of this species will place the egg on the male's feet to keep warm in his fat folds while she goes out and hunts for several weeks. When penguin chicks are ready to hatch, they use their beak

"Which species of decapod has varieties called ""fiddler', 'spider' and 'hermit'?"

decapod | crustacean | Britannica.com crustacean 3-22-2013 Alternative Title: Decapoda Decapod, (order Decapoda), any of more than 8,000 species of crustaceans (phylum Arthropoda) that include shrimp, lobsters, crayfish , hermit crabs, and crabs. Masked crab (Corystes cassivelanus), Belgian coast. Hans Hillewaert The presence of five pairs of thoracic legs (pereiopods) is the basis for the name decapod (from the Greek meaning “10 legs”). Members of the order exhibit great diversity in size and structure. The macrurous (shrimplike) species, which can be as small as 1 cm (0.5 inch), have elongated bodies with long abdomens, well-developed fan tails, and often long, slender legs. The brachyurous (crablike) types, which in the case of spider crabs can have spans of almost 4 metres ... (100 of 840 words) MEDIA FOR:

Which digestive organ is well-developed in grass-eating herbivores, but is only vestigial in humans?

Anatomy and Physiology of Animals/The Gut and Digestion - Wikibooks, open books for an open world Anatomy and Physiology of Animals/The Gut and Digestion From Wikibooks, open books for an open world original image by vnysia cc by Contents After completing this section, you should know: what is meant by the terms: ingestion, digestion, absorption, assimilation, egestion, peristalsis and chyme the characteristics, advantages and disadvantages of a herbivorous, carnivorous and omnivorous diet the 4 main functions of the gut the parts of the gut in the order in which the food passes down it The Gut And Digestion[ edit ] Plant cells are made of organic molecules using energy from the sun. This process is called photosynthesis. Animals rely on these ready-made organic molecules to supply them with their food. Some animals (herbivores) eat plants; some (carnivores) eat the herbivores. Herbivores[ edit ] Herbivores eat plant material. While no animal produces the digestive enzymes to break down the large cellulose molecules in the plant cell walls, micro-organisms' like bacteria, on the other hand, can break them down. Therefore herbivores employ micro-organisms to do the job for them. There are three types of herbivore: The first, ruminants like cattle, sheep and goats, house these bacteria in a special compartment in the enlarged stomach called the rumen. The second group has an enlarged large intestine and caecum, called a functional caecum, occupied by cellulose digesting micro-organisms. These non-ruminant herbivores include the horse, rabbit and rat. Humans also have a cecum and can be classified as the third type of herbivorous class, along with orangutans and gorillas. Plants are a primary pure and good source of nutrients, however they are digested very easily and therefore herbivores have to eat large quantities of food to obtain all they require. Herbivores like cows, horses and rabbits typically spend much of their day feeding. To give the micro-organisms access to the cellulose molecules, the plant cell walls need to be broken down. This is why herbivores have teeth that are adapted to crush and grind. Their guts also tend to be lengthy and the food takes a long time to pass through it. Eating plants have other advantages. Plants are immobile so herbivores normally have to spend little energy collecting them. This contrasts with another main group of animals - the carnivores that often have to chase their prey. Carnivores[ edit ] Carnivorous animals like those in the cat and dog families, polar bears, seals, crocodiles and birds of prey catch and eat other animals. They often have to use large amounts of energy finding, stalking, catching and killing their prey. However, they are rewarded by the fact that meat provides a very concentrated source of nutrients. Carnivores in the wild therefore tend to eat distinct meals often with long and irregular intervals between them. Time after feeding is spent digesting and absorbing the food. The guts of carnivores are usually shorter and less complex than those of herbivores because meat is easier to digest than plant material. Carnivores usually have teeth that are specialised for dealing with flesh, gristle and bone. They have sleek bodies, strong, sharp claws and keen senses of smell, hearing and sight. They are also often cunning, alert and have an aggressive nature. Omnivores[ edit ] Many animals feed on both animal and vegetable material – they are omnivorous. Most primates are herbivorous but a few, such as chimpanzees and humans, belong to this category as do pigs and rats. Their food is diverse, ranging from plant material to animals they have either killed themselves or scavenged from other carnivores. Omnivores lack the specialised teeth and guts of carnivores and herbivores but are often highly intelligent and adaptable reflecting their varied diet. Treatment Of Food[ edit ] Whether an animal eats plants or flesh, the carbohydrates, fats and proteins in the food it eats are generally giant molecules (see chapter 1). These need to be split up into smaller ones befo

Which are the only birds able to fly backwards?

What Bird Can Fly Backwards? - It May Suprise You About The Weasel What Bird Can Fly Backwards? Most living things we see on a daily basis (including other people) have the ability to both move forward and backwards. Do our airborne bird counterparts get to experience the same luxury? As it turns out, 99% of all birds lack the ability to fly backwards. This inability is mostly a function of a bird’s wings. Most birds have a wing structure that includes extra strong muscles that pull their wings downward. These same birds usually have much weaker muscles designed to pull their wings back up as they rely on wind resistance to do most of the work. While some birds may give the visual perception of flying backwards, most still lack the ability to do so without assistance from wind. Ospreys, kestrels, kingfishers, and cuckoo are often mistaken for a bird species that are magically flying backwards in this manner. Some birds can move backward slightly using a fluttering method. This is common among herons , egrets , warblers , and flycatchers . There exists only one species of bird that can reliably fly both forward and backward with precision without relying on the assistance of wind. In fact, this bird species can fly side to side, hover, and mostly move what can best be described as a “flying ninja.” We are referring to the Hummingbird: the most nimble and tactical species of all birds. How Does the Hummingbird Fly Backwards The hummingbird has a unique muscle and wing structure that gives them a level of flight control that other birds envy (or at least we do). You can think of a hummingbird as a miniature helicopter. Like a helicopter, the hummingbird can hover, fly right to left, left to right, diagonal, forwards, and yes, even backwards. The hummingbird has the ability to rotate its wings in circles making a figure eight. Based on the configuration of the figure eight as shown below, the hummingbird can change directions at will. So not only does the hummingbird fly backwards, it does so with great speed and grace. In fact, they fly at a speed of up to 30 mph! If you ever observe one, you will without a doubt notice their quickness. You may also notice that their wings move so quickly that they are just a blur. This blurred effect is a result of their wings flapping between 15 t0 100 times per second to maintain the kind of agility to allow them to fly backwards. Birds that Fly Backwards: Interesting Facts The heart rate of a hummingbird can reach over 1,000 beats a minute. The fast-paced wing flapping creates a humming noise, which gives them their name. 1/3rd of a hummingbirds total weight comes from the muscles it uses to fly. Hummingbirds are constantly eating in order to fuel their flight agility; they have the highest metabolisms of all birds. In one day, a hummingbird will eat twice its body weight to survive. Luckily for the hummingbird, they expend the same amount of energy moving forward as they do moving backwards!

Photosynthesis is carried out in which part of the cell?

The Cell, Respiration and Photosynthesis A Primer on Photosynthesis and the Functioning of Cells   Photosynthesis Photosynthesis is the process by which organisms that contain the pigment chlorophyll convert light energy into chemical energy which can be stored in the molecular bonds of organic molecules (e.g., sugars). Photosynthesis powers almost all trophic chains and food webs on the Earth.  The net process of photosynthesis is described by the following equation:  6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2 This equation simply means that carbon dioxide from the air and water combine in the presence of sunlight to form sugars; oxygen is released as a by-product of this reaction.    PGA is a phosphoglyceric acid, a three carbon (C-C-C) organic acid. Grana are the stacked membranes that contain chlorophyll. RuBP is the five carbon (C-C-C-C-C) sugar-phosphate. Rubisco is the enzyme ribulose bisphosphate carboxylase/oxygenase. It is the enzyme that catalyzes the conversion of CO2 to the organic acid, PGA. It is the most abundant enzyme on Earth.  During the process of photosynthesis, light penetrates the cell and passes into the chloroplast. The light energy is intercepted by chlorophyll molecules on the granal stacks. Some of the light energy is converted to chemical energy. During this process, a phosphate is added to a molecule to cause the formation of ATP. The third phosphate chemical bond contains the new chemical energy. The ATP then provides energy to some of the other photosynthetic reactions that are causing the conversion of CO2 into sugars.  While the above reactions are proceeding CO2 is diffusing into the chloroplast. In the presence of the enzyme Rubisco, one molecule of CO2 is combined with one molecule of RuBP, and the first product of this reaction is two molecules of PGA.  The PGA then participates in a cycle of reactions that result in the production of the sugars and in the regeneration of RuBP. The RuBP is then available to accept another molecule of CO2 and to make more PGA.  Which wavelengths of the solar spectrum drive photosynthesis?   The wavelengths of sunlight between 400nm and 700nm are the wavelengths that are absorbed by chlorophyll and that drive photosynthesis.   Energy Incident on a Leaf Photosynthesis is not a very efficient process. Of the sunlight reaching the surface of a leaf, approximately:   Respiration is the opposite of photosynthesis, and is described by the equation: C6H12O6+6O2 ----------> 6CO2+6H2O+36ATP Simply stated, this equation means that oxygen combines with sugars to break molecular bonds, releasing the energy (in the form of ATP) contained in those bonds. In addition to the energy released, the products of the reaction are carbon dioxide and water.  In eukaryotic cells, cellular respiration begins with the products of glycolysis being transported into the mitochondria. A series of metabolic pathways (the Krebs cycle and others) in the mitochondria result in the further breaking of chemical bonds and the liberation of ATP. CO2 and H2O are end products of these reactions. The theoretical maximum yield of cellular respiration is 36 ATP per molecule of glucose metabolized.  **  Note that photosynthesis is a reduction-oxidation reaction, just like respiration (see the primer on redox reactions from the lecture on Microbes). In respiration energy is released from sugars when electrons associated with hydrogen are transported to oxygen (the electron acceptor), and water is formed as a byproduct.  The mitochondria use the energy released in this oxidation in order to synthesize ATP.  In photosynthesis, the electron flow is reversed, the water is split (not formed), and the electrons are transferred from the water to CO2 and in the process the energy is used to reduce the CO2 into sugar.  In respiration the energy yield is 686 kcal per mole of glucose oxidized to CO2, while photosynthesis requires 686 kcal of energy to boost the electrons from the water to their high-energy perches in the reduced sugar -- light provides this energy.

What is the name of the protective outer layer of trees?

The Protective Layer – Peace and Healing A Perspective of Traditional and Non-Traditional Methods of Healing The Protective Layer November 12, 2011 by Dan Williams, Psy.D.,P.A.-C. | 0 comments Our skin, the largest organ of our body. It protects us from the elements as well as helping with our body temperature. If one has ever cut down a tree you have noticed the protective layer of the bark. Also an insulator as well as a protector of nutrients that flow up the trunk. Damage the bark significantly and you see a scar for the rest of the tree’s life. Even our brain has a protective outer layer called dura mater, “tough mother.” The protection of many animals, trees, plants and even insects have protective outer layers to escape predators as well as protection from the elements. What about our emotions, our soul, our spirit? What is the protective layer of our emotions? Is it any wonder that paramedics, police officers, and those in active combat become calloused or to the contrary do not, and suffer PTSD, post traumatic stress disorder. It IS our very perception of self, combined with experience and our success, as well as failure that protects our soul our living spirit. When met with repetitious life trauma, emotional devastation repeatedly we may weaken, however this is also the process that develops character. The outer layer that protects our spirit, our soul, our emotional demeanor is our perception of life and how we chose to handle it. Nothing more, nothing less. Why the surge on self help books, the quest for the “right” religion, the need to question our belief versus listening to a loved one try and convince us to accept a certain religious paradigm. When pushed to the limit of stress. When we feel we are ready to break. When the emotion upheaval is so heavy upon our ability to cope, we may rely on others to converse. When we hang up the phone, leave the therapy session or begin to walk our walk of life….in the end it is always “YOU” that goes to bed at night when the covers are tucked up under your chin. Recognize the protective layer is your perception, your attitude, your belief. It is the make or break in terms of happiness and success when dealing with stress and life trauma. If one has a shattered or weak perception of self, it takes minimal understanding to see one shaken, one rattled and disoriented on which path to take. We sometimes over compensate and build a very calloused layer to protect the wounded soul. The emotional bark becomes thicker and at times impenetrable.  It is up to us to soften the outer layer with time, personal growth and trusting others. Yes, it takes time. Sometimes, like the tree hit by lightning, the scar remains and rears it’s ugly head in the form of anger, tears, or condescending behavior. Sarcasm, the wonderful defense to softness. It is humorous, but when used frequently is a defense mechanism to avoid. The avoidance of closeness. I know few people that would want to hug a hawthorn tree with it’s wooden barbs emitting out from the trunk as if it were a  Medieval  weapon. Humans can grow these thorns as well as remove them. We have the opportunity to become guarded and protective. We also have the ability to let the guard down and become soft and giving. The balance. Ah, the balance. Humans must learn and understand their own protective layer. The skin of their soul. The bark around their spirituality. It is important to protect ourselves, however too much protection and we live emotionally lonely lives, where we can rationalize our very existence. We can convince ourselves we are happy, when we are not. Understand the importance of your protective layer and how it changes with certain individuals. Decide how you want to live. Maybe you need to be more protective of your soul and just maybe you need to open up and become more vulnerable. Either way, recognize the protective layer and your responsibility in owning it.

What liquid do plants need for photosynthesis?

UCSB Science Line UCSB Science Line Why do plants need water? Answer 1: All living things need water to stay alive, and plants are living things! Plants, however, need much more water than many living things because plants use much more water than most animals. Plants also contain more water than animals - plants are about 90% water. The amount of water a plant needs depends on the type of plant, how much light the plant gets, and how old the plant is. When plants are not watered properly they wilt. This is because of something called turgor, which is water pressure inside the cells that make up the plant's skeleton. Water enters a plant through its stem and travels up to its leaves. When a plant is properly hydrated, there is enough water pressure to make the leaves strong and sturdy; when a plant doesn't get enough water, the pressure inside the stems and leaves drops and they wilt. Plants also need water for photosynthesis. Photosynthesis is what plants do to create their food, and water is critical to this process. Water enters a plant's stem and travels up to its leaves, which is where photosynthesis actually takes place. Once in the leaves water evaporates, as the plant exchanges water for carbon dioxide. This process is called transpiration, and it happens through tiny openings in the plant's leaves, called stomata. The water from the leaves evaporates through the stomata, and carbon dioxide enters the stomata, taking the water's place. Plants need this carbon dioxide to make food. Transpiration - this exchange of water for carbon dioxide - only occurs during the day when there is sunlight. This is why you might find dew on plants in the morning. The plants contain a lot of water because all night long water has been entering through the stem and being pulled into the leaves where it can't evaporate. Since the water doesn't evaporate at night, the water has no where to go so it remains on the leaves as dew. When water evaporates from a plant during transpiration it cools the plant, in the same way the humans sweat to cool off in the heat. A mature house plant can transpire its body weight daily. This means it gives off a lot of water! If people needed that much water, an adult would drink 20 gallons of water a day. Answer 2: Actually, all living things need water because life requires a LOT of chemical reactions. The chemicals are usually dissolved in water. Also, plants put the water together with carbon dioxide to make sugar. This takes energy, which plants get from light. Water also helps plants stand up tall, even when they aren’t made of wood. They don’t have bones, but they do have cell walls and water pressure. Water comes up from the roots, but carbon dioxide doesn’t. How do you think plants get carbon dioxide? Thanks for asking, Answer 3: The plants need water because the reactions that take place in the cell to make energy require a watery medium. Answer 4: Plants need water for the same reason that all living things do: to dissolve the chemicals they use to do their biology. Plants also use a water current up the plant for transport, which evaporates water out the leaves, so they need water for that reason, too. Lastly, water is used to make sugar, and plants store energy in the form of sugar. Click Here to return to the search form. Copyright © 2015 The Regents of the University of California, All Rights Reserved.

What are the young of bats called?

Bats | Basic Facts About Bats | Defenders of Wildlife Bats Basic Facts About Bats Bats are the only mammals capable of true flight. With extremely elongated fingers and a wing membrane stretched between, the bat’s wing anatomically resembles the human hand. Almost 1,000 bat species can be found worldwide. In fact, bats make up a quarter of all mammal species on earth! Diet 70% of bats consume insects, sharing a large part of natural pest control. There are also fruit-eating bats; nectar-eating bats; carnivorous bats that prey on small mammals, birds, lizards and frogs; fish-eating bats, and perhaps most famously, the blood-sucking vampire bats of South America. Population While some bat populations number in the millions, others are dangerously low or in decline. Range Did You Know? A single little brown bat can eat up to 1000 mosquitoes in a single hour, and is one of the world's longest-lived mammals for its size, with life spans of almost 40 years. Bats can be found almost anywhere in the world except the polar regions and extreme deserts. Behavior Echolocation Some bats have evolved a highly sophisticated sense of hearing. They emit sounds that bounce off of objects in their path, sending echoes back to the bats. From these echoes, the bats can determine the size of objects, how far away they are, how fast they are traveling and even their texture, all in a split second Bats find shelter in caves, crevices, tree cavities and buildings. Some species are solitary while others form colonies of more than a million individuals. Did You Know? Giant flying foxes that live in Indonesia have wingspans of nearly six feet! Overwintering To survive the winter some species of bat migrate, others hibernate, and yet others go into torpor (regulated hypothermia that can last from a few hours to a few months). Reproduction Gestation: 40 days - 6 months (bigger bats have longer gestation periods) Litter Size: Mostly one pup For their size, bats are the slowest reproducing mammals on Earth. At birth, a pup weighs up to 25 percent of its mother’s body weight, which is like a human mother giving birth to a 31 pound baby! Offspring typically are cared for in maternity colonies, where females congregate to bear and raise the young. Male bats do not help to raise the pups

What is the larva of a toad called?

Larval forms | Article about Larval forms by The Free Dictionary Larval forms | Article about Larval forms by The Free Dictionary http://encyclopedia2.thefreedictionary.com/Larval+forms Also found in: Dictionary , Thesaurus , Medical , Wikipedia . larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or microscopic, they are rarely seen. They play diverse roles in the lives of animals. Motile larvae help to disseminate sessile, or sedentary, animals such as sponges sponge, common name for members of the aquatic animal phylum Porifera, and for the dried, processed skeletons of certain species used to hold water. Over 4,500 living species are known; they are found throughout the world, especially in shallow temperate waters. ..... Click the link for more information. , oysters oyster, bivalve mollusk found in beds in shallow, warm waters of all oceans. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface. ..... Click the link for more information. , barnacles barnacle, common name of the sedentary crustacean animals constituting the infraclass Cirripedia. Barnacles are exclusively marine and are quite unlike any other crustacean because of the permanently attached, or sessile, mode of existence for which they are highly modified. ..... Click the link for more information. , or scale insects. Larvae of parasites may be dispersed by penetrating the skin of new hosts; other parasite larvae live in intermediate hosts that are normally eaten by the final host, in which the adult parasites develop. The larvae of other parasites live in and are dispersed by intermediate hosts such as mosquitoes mosquito , small, long-legged insect of the order Diptera, the true flies. The females of most species have piercing and sucking mouth parts and apparently they must feed at least once upon mammalian blood before their eggs can develop properly. ..... Click the link for more information. , gnats gnat, common name for any one of a number of small, fragile-looking two-winged flies of the suborder Nematocera, order Diptera, which includes the families Tipulidae (crane flies), Bibionidae (hairflies), Ceratopogonidae (biting midges), Chironomidae (true midges), Cecidomyidae ..... Click the link for more information. , or leeches leech, predacious or parasitic annelid worm of the class Hirudinea, characterized by a cylindrical or slightly flattened body with suckers at either end for attaching to prey. ..... Click the link for more information. ; when the blood meals are taken from the final host, the parasite larvae are introduced into the blood or skin. Parasitic infections can often be reduced by eliminating the larval hosts. Vertebrate Larvae Among vertebrates vertebrate, any animal having a backbone or spinal column. Verbrates can be traced back to the Silurian period. In the adults of nearly all forms the backbone consists of a series of vertebrae. All vertebrates belong to the subphylum Vertebrata of the phylum Chordata. ..... Click the link for more information.  a number of fishes fish, limbless aquatic vertebrate animal with fins and internal gills. Traditionally the living fish have been divided into three class: the primitive jawless fishes, or Agnatha; the cartilaginous (sharklike) fishes, or Chondrichthyes; and the bony fishes, or Osteichthyes. ..... Click the link for more information.  pass through larval stages; the larva of the eel eel, common name for any fish in the order Anguilliformes, and characterized by a long snakelike body covered with minute scales embedded in the skin. Eels lack the hind pair of fins, adapting them for wriggling in the mud and through the crevices of reefs and rocky shores. ..... Click the link for more information.  is interesting because it is flat and transparent. The tadpole, the familiar larva of the amphibian amphibian, in zoology, cold-blooded vertebrate animal of the class Amphibia. Th

Which bird, a member of the cuckoo family, is often seen dashing along the highways of the southern USA and Mexico... hence its name?

/programmes/b04t0vqb Mauritius Kestrel Michael Palin presents the Mauritius kestrel from the island of Mauritius. Today the calls of several hundred Mauritius kestrels ring out across the forests and farmland of the island, so it's hard to believe that as recently as the early 1970s, only four birds could be found in the wild. These smart chestnut falcons were almost wiped out by a cocktail of threats ...destruction of their evergreen forests, pesticides and the introduction of predators such as monkeys, mongooses, rats and cats. When a species is so critically endangered there aren't many options, and conservationists decided that their only choice was to take some of the wild Mauritius kestrels into captivity. By 1993, 300 Mauritius kestrels had been released and by November of that year there were as many as 65 breeding pairs in the wild. Now the kestrels are back, hovering above the landscapes that nearly lost them forever. Michael Palin presents the Mauritius kestrel, from the island of Mauritius. Michael Palin presents the Mauritius kestrel from the island of Mauritius. Today the calls of several hundred Mauritius kestrels ring out across the forests and farmland of the island, so it's hard to believe that as recently as the early 1970s, only four birds could be found in the wild. These smart chestnut falcons were almost wiped out by a cocktail of threats ...destruction of their evergreen forests, pesticides and the introduction of predators such as monkeys, mongooses, rats and cats. When a species is so critically endangered there aren't many options, and conservationists decided that their only choice was to take some of the wild Mauritius kestrels into captivity. By 1993, 300 Mauritius kestrels had been released and by November of that year there were as many as 65 breeding pairs in the wild. Now the kestrels are back, hovering above the landscapes that nearly lost them forever. Thu, 12 Feb 2015 00:00:00 +0000 102 /programmes/b04t0vp4 Ostrich Michael Palin presents the avian record breaking ostrich in the Kalahari Desert. Ostriches are ornithological record-breakers. The black and white adult male ostrich is taller and heavier than any other living bird, reaching almost 3 metres in height and weighing a whopping 150 kilograms. Females are smaller but lay the largest eggs of any bird. The ostrich's eye measures 5cm in diameter and is the largest of any land vertebrate. Ostriches live in the wide open landscapes of central, eastern and South-West Africa. As well as being tall and observant, Ostriches also minimise their chances of being predated on, by living in groups and sharing lookout duties, or staying close to sharp-eyed antelope and zebra herds. They can also use their powerful legs to try and outrun a predator, reaching speeds of up to 70 kilometres per hour which makes them the fastest avian runner. Michael Palin presents the ostrich, an avian record-breaker, in the Kalahari Desert. Michael Palin presents the avian record breaking ostrich in the Kalahari Desert. Ostriches are ornithological record-breakers. The black and white adult male ostrich is taller and heavier than any other living bird, reaching almost 3 metres in height and weighing a whopping 150 kilograms. Females are smaller but lay the largest eggs of any bird. The ostrich's eye measures 5cm in diameter and is the largest of any land vertebrate. Ostriches live in the wide open landscapes of central, eastern and South-West Africa. As well as being tall and observant, Ostriches also minimise their chances of being predated on, by living in groups and sharing lookout duties, or staying close to sharp-eyed antelope and zebra herds. They can also use their powerful legs to try and outrun a predator, reaching speeds of up to 70 kilometres per hour which makes them the fastest avian runner. Wed, 11 Feb 2015 00:00:00 +0000 104 /programmes/b04t0vl3 Asian Koel Michael Palin presents the Asian koel's arrival to an Indian orchard. This long-tailed glossy blue-black bird, is a well-known British harbinger of spring, and like it's British counterpart

What grow as parasites and saprotrophs, contain no chlorophyll, and reproduce by means of spores?

Fungi kingdom - definition of Fungi kingdom by The Free Dictionary Fungi kingdom - definition of Fungi kingdom by The Free Dictionary http://www.thefreedictionary.com/Fungi+kingdom Related to Fungi kingdom: Protista kingdom fun·gus  (fŭng′gəs) n. pl. fun·gi (fŭn′jī, fŭng′gī) or fun·gus·es Any of numerous spore-producing eukaryotic organisms of the kingdom Fungi, which lack chlorophyll and vascular tissue and range in form from a single cell to a mass of branched filamentous hyphae that often produce specialized fruiting bodies. The kingdom includes the yeasts, smuts, rusts, mushrooms, and many molds, excluding the slime molds and the water molds. [Latin; perhaps akin to Greek spongos, sphongos, sponge.] fungus (ˈfʌŋɡəs) n, pl fungi (ˈfʌŋɡaɪ; ˈfʌndʒaɪ; ˈfʌndʒɪ) or funguses 1. (Plants) any member of a kingdom of organisms (Fungi) that lack chlorophyll, leaves, true stems, and roots, reproduce by spores, and live as saprotrophs or parasites. The group includes moulds, mildews, rusts, yeasts, and mushrooms 2. something resembling a fungus, esp in suddenly growing and spreading rapidly 3. (Pathology) pathol any soft tumorous growth [C16: from Latin: mushroom, fungus; probably related to Greek spongos sponge] fungic adj n., pl. fun•gi (ˈfʌn dʒaɪ, ˈfʌŋ gaɪ) fun•gus•es. any member of the kingdom Fungi (or division Thallophyta of the kingdom Plantae), comprising single-celled or multinucleate organisms that live by decomposing and absorbing the organic material in which they grow: includes the mushrooms, molds, mildews, smuts, rusts, and yeasts. [1520–30; < Latin: fungus; sponge ] fun•gic (ˈfʌn dʒɪk) adj. fun·gus (fŭng′gəs) Plural fungi (fŭn′jī, fŭng′gī) Any of a wide variety of organisms that reproduce by spores, including the mushrooms, molds, yeasts, and mildews. The spores of most fungi grow a network of slender tubes called hyphae that spread into and feed off of living organisms or dead organic matter. The hyphae also produce reproductive structures, such as mushrooms and other growths. Fungi are grouped as a separate kingdom in taxonomy. See Table at taxonomy . fungal adjective Did You Know? There's a fungus among us, as they say. And it's true—they are everywhere. You have no doubt eaten mushrooms, which are fungi. And you have eaten bread, made with yeast, another fungus. Old bread may grow mold, still another fungus. Athlete's foot and a variety of other infections are caused by fungi, but, on the good side, a fungus also produces the medicine penicillin. About 100,000 different species of fungi exist. When you see a light-colored splat on a tree or rock in the woods, it is probably a lichen, which is a fungus and an alga living in a symbiotic relationship, benefiting each other. Fungi are neither plants nor animals; they are different enough to be classified by scientists into their own unique kingdom. fungus (pl. fungi) A member of the kingdom Fungi, a group of nonmotile saprophytes and parasites. ThesaurusAntonymsRelated WordsSynonymsLegend: Noun 1. fungus - an organism of the kingdom Fungi lacking chlorophyll and feeding on organic matter; ranging from unicellular or multicellular organisms to spore-bearing syncytia organism , being - a living thing that has (or can develop) the ability to act or function independently immune reaction , immune response , immunologic response - a bodily defense reaction that recognizes an invading substance (an antigen: such as a virus or fungus or bacteria or transplanted organ) and produces antibodies specific against that antigen pileus , cap - a fruiting structure resembling an umbrella or a cone that forms the top of a stalked fleshy fungus such as a mushroom volva - cuplike structure around the base of the stalk of certain fungi hymenium - spore-bearing layer of cells in certain fungi containing asci or basidia Ceratostomella ulmi , Dutch elm fungus - fungus causing Dutch elm disease Claviceps purpurea , ergot - a fungus that infects various cereal plants forming compact black masses of branching filaments that replace many grains of the plant; source of medicinally important a

Why do fish have gills?

How Fish Gills Work How Fish Gills Work Today I found out how fish gills work. These fantastic little organs allow the fish to absorb oxygen from the water and use it for energy. Functionally, gills are not that dissimilar to the lungs in humans and other mammals. The main difference is how they are able to absorb much smaller concentrations of available oxygen, while allowing the fish to maintain an appropriate level of Sodium Chloride (salt) in their bloodstream. Gills work on the same principle as lungs. In the lungs, there are small sacs called alveoli that are approximately 70% capillaries. These capillaries carry deoxygenated blood from the body. As oxygen and carbon dioxide pass across the alveoli’s membrane, the capillaries take the newly oxygenated blood back to the body. Similarly, gills have small rows and columns of specialized cells grouped together called the epithelium. Deoxygenated blood in the fish is supplied directly from the heart to the epithelium via arteries, and even yet smaller arterioles. As seawater is forced across the epithelium membranes, dissolved oxygen in the seawater is taken up by tiny blood vessels and veins, while the carbon dioxide is exchanged. Gills themselves have a car radiator-like appearance. Most fish have 4 gills on each side, consisting of a main bar-like structure that has numerous branches as that of a tree, and those branches consisting of even smaller branch-like structures. This arrangement of cells allows for a very large surface area when the gills are immersed in water. Functionally, the mechanism for pumping water over the radiator-like gills seems to vary depending on the species of fish. In general, this is achieved by the fish lowering the floor of the mouth and widening the outer skin flap that protects the gills, called the operculum. This increase in volume lowers the pressure within the mouth causing the water to rush in. As the fish raises the floor of their mouth, an inward fold of skin forms a valve of sorts which doesn’t allow water to rush out. The pressure is then increased compared to the outside of the mouth and the water is forced through the operculum opening and across the gills. Gills themselves need a very large surface area to provide the fish with the necessary oxygen demands. Air is approximately 21% oxygen or about 210,000 parts per million. Water, on the other hand, only has about 4-8 parts per million of dissolved oxygen that the gills can extract. Because of this, if the fish did not have a large gill surface area to absorb as much oxygen as it can for it’s size, it would quickly suffocate. Cold blooded animals also tend to have a lower metabolism than their warm blooded counterparts. This aids them in their ability to handle environments of low available oxygen. Should the same size fish be warm blooded, the metabolism of the little swimmer would be increased to the point that the available oxygen would not be sufficient and little Nemo would perish. While the large gill surface area allows for sufficient exchange of carbon dioxide and oxygen, it at the same time exposes the same large blood volume to the hypertonic (that is, saltier than thou) sea water, creating a situation in which fish must have a backup mechanism for expelling excess sodium that has been incidentally absorbed. Conversely, freshwater fish need to have an opposite mechanism allowing them to excrete excess water to keep their sodium levels appropriately high. Never mind about those anadromous gypsies who trounce back and forth, able to thrive in both fresh and salt water environments. We will just call them show offs and leave it at that. To deal with this sodium problem, inside the gill resides nifty little cells called chloride cells. These cells allow for the extrusion of any unwanted sodium. Freshwater fish tend to have less of these cells than do their seafaring counterparts. This, combined with the ability to have extremely diluted urine, allows fresh water fish to keep their sodium level appropriately high.

Which animal can move by jet propulsion?

What is a nautilus? Home Ocean Facts What is a nautilus? What is a nautilus? The nautilus is a mollusk that uses jet propulsion to roam the ocean deep. Writers, artists, and engineers have long marveled at the nautilus’s beauty and swimming abilities. The chambered or pearly nautilus is a cephalopod (a type of mollusk)—a distant cousin to squids, octopi, and cuttlefish. Unlike its color-changing cousins, though, the soft-bodied nautilus lives inside its hard external shell. The shell itself has many closed interior chambers or “compartments.” The animal resides in the shell’s largest chamber, while the other chambers function like the ballast tanks of a submarine. This is the secret to how the nautilus swims. The tissue in a canal called the siphuncle [sigh-funk-el] connects all of the interior chambers. As seawater pumps through the living chamber, the nautilus expels water by pulling its body into the chamber, thereby creating jet propulsion to thrust itself backwards and to make turns. While swimming up or down through the water column, the nautilus uses its siphuncle to suck fluid into, or draw it out of, the smaller sealed chambers, allowing the animal to adjust its overall buoyancy. According to fossil records, animals similar to the chambered nautilus have existed for about 500 million years. Although no regulations currently exist to protect them, the six living species of chambered nautilus appear to be in decline. They are trapped mostly for their attractive shells and also for the shell’s inner layer, called nacre, which is used as a pearl substitute in jewelry and trinkets. In 2013, NOAA Fisheries funded a University of Washington researcher to conduct population studies of the nautilus in Fiji and American Samoa. The research should provide a clearer picture of nautilus abundance in those areas. Search Our Facts

What name is given to the microscopic plants found in great numbers in rivers, lakes, and oceans?

Aquatic Plants and Lakes Ecology home > Water Quality > Aquatic Plants, Algae & Lakes > Native Freshwater Plants - Aquatic Plants and Lakes Native Freshwater Plants Aquatic Plants and Lakes Introduction Plants growing in our lakes, ponds, and streams are called macrophytes. These aquatic plants appear in many shapes and sizes.  Some have leaves that float on the water surface,while others grow completely underwater. In moderation, aquatic plants are aesthetically pleasing and desirable environmentally. Their presence is natural and normal in lakes, and in fact they are an important link in a lake's life system. In large quantities, plants can interfere with some water uses and may be seen as a problem. When lake users are confronted with too many plants in the wrong places, a common reaction is to remove the entire problem. Such hasty decisions are often made with little regard for the important role plants play in the water environment. Neglecting to see these interrelations often results in unintended impacts to wildlife, fish, and other forms of life. Unfortunately, the information required to make environmentally sound decisions is not always easily available. Without this information, how can anyone know what is best over the long term to do about aquatic plants? The purpose of this information is to provide some general but pertinent information and insights regarding aquatic plants:  (1) how they came to be where they are, (2) what beneficial contributions that they make to life in the lake, (3) how our activities can affect them, and (4) some things to consider if plant removal is planned. Acknowledgments: This information was taken from a brochure called About Aquatic Plants written by the Municipality of Metropolitan Seattle's (METRO) Water Resource Section (now King County). Life History of a Lake A question frequently raised regarding aquatic plants is why some lakes have them in abundance and others do not. An answer to this question lies in the explanation of the lake's aging cycle. Most of our local lakes came into being as a result of activity of glaciers in the most recent ice age, approximately 10,000 years ago. A lake bed is a natural depression or low spot in the terrain. In the Puget Sound lowlands they were often gouged out by movement of glacial ice. These depressions then became holding basins for water of the drainage area as it flowed toward sea level. As a lake detains water on its way downstream, it also becomes a settling pond for sediment.  Part of the sediment that settles in lakes is carried in by the flow of streams or other runoff, and part comes from the accumulation of the remains of organisms in the water and near the shoreline. Aquatic life includes visible plants and animals and also multitudes of microscopic plants and animals that can, over time, add significantly to the accumulation of sediment in the lake by dying and settling to the bottom. The microscopic plants in the water are nourished by plant nutrients (phosphorus and nitrogen) that originate in the watershed and are washed into the lake. Within the lake, a portion of these nutrients can be recycled indefinitely, while more continue to be washed in from the lake basin. Over time sediment accumulates in the lake as productivity gradually increases. When first formed, many of the lake beds were deep and clean (mostly free of sediment). Sediments that were first deposited were silty and had little organic material because there was little life in or around the lakes. Over time, hundreds or thousands of years, the sediment deposits became deeper and more favorable to the growth of rooted, aquatic plants (macrophytes). As these plants (and the microscopic life in the water, now also more abundant) died back at the end of each growing season or life cycle, they enriched the sediments with organic material. Since macrophytes tend to grow better in organically richer sediments, this process set up a cycle of more growth in the lake causing richer sediments and these in turn favored ev

What are the nocturnal, herding herbivores of Australia, Tasmania, and New Guinea?

ANIMAL KINGDOM :: MARSUPIAL MAMMALS :: EXAMPLES OF MARSUPIALS image - Visual Dictionary Online Visual Dictionary Online next Tasmanian devil Carnivorous scavenging nocturnal marsupial with powerful jaws that allow it to devour its prey whole (flesh, bones, fur, feathers). opossum Omnivorous nocturnal marsupial of the Americas and Australia without a pouch; its fur is highly prized. wallaby Marsupial closely related to the kangaroo and living in Australia, Tasmania and New Guinea; certain species are prized for their fur. morphology of a kangaroo koala Tailless nocturnal marsupial of Australia; this solitary tree-dweller lives in eucalyptus forests and feeds on the tree&#8217s leaves. kangaroo Herbivorous marsupial with a highly developed tail; it lives in groups in Australia and Tasmania and moves rapidly by leaping.

Where in an animal would you find a mandible?

Jaw - definition of jaw by The Free Dictionary Jaw - definition of jaw by The Free Dictionary http://www.thefreedictionary.com/jaw n. 1. a. Either of two bony or cartilaginous structures that in most vertebrates form the framework of the mouth and hold the teeth. b. The mandible or maxilla or the part of the face covering these bones. c. Any of various structures of invertebrates that have an analogous function to vertebrate jaws. 2. Either of two opposed hinged parts in a mechanical device. 3. jaws The walls of a pass, canyon, or cavern. 4. jaws A dangerous situation or confrontation: the jaws of death. 5. Slang a. Impudent argument or back talk: Don't give me any jaw. b. A conversation or chat. intr.v. jawed, jaw·ing, jaws Slang 1. To talk vociferously; jabber. 2. To talk; converse. [Middle English jawe, jowe, perhaps from Old French joue, cheek.] jaw′less adj. (dʒɔː) n 1. (Zoology) the part of the skull of a vertebrate that frames the mouth and holds the teeth. In higher vertebrates it consists of the upper jaw (maxilla) fused to the cranium and the lower jaw (mandible). 2. (Zoology) the corresponding part of an invertebrate, esp an insect 3. (Mechanical Engineering) a pair or either of a pair of hinged or sliding components of a machine or tool designed to grip an object 4. slang c. moralizing talk; a lecture vb a. to talk idly; chat; gossip b. to lecture [C14: probably from Old French joue cheek; related to Italian gota cheek] ˈjawˌlike adj (dʒɔ) n. 1. either of two tooth-bearing bones or bony structures, the mandible or maxilla, forming the framework of the vertebrate mouth. 2. the part of the face covering these bones. 3. jaws, anything resembling a pair of jaws in shape or in power to grasp or hold. 4. one of two or more parts, as of a machine, that grasp or hold something or that attach to or mesh with similar parts. 5. Slang. an idle chat. v.i. 6. Slang. to chat; gossip. [1325–75; Middle English jawe, jowe < Old French joue; orig. uncertain] jaw′less, adj. jaw (jô) 1. Either of two bony or cartilaginous structures that in most vertebrate animals form the framework of the mouth, hold the teeth, and are used for biting and chewing food. The lower, movable part of the jaw is called the mandible. The upper, fixed part is called the maxilla. 2. Any of various structures of invertebrate animals, such as the pincers of spiders or mites, that function similarly to the jaws of vertebrates. jaw I will have been jawing you will have been jawing he/she/it will have been jawing we will have been jawing you will have been jawing they will have been jawing Past Perfect Continuous Noun 1. jaw - the part of the skull of a vertebrate that frames the mouth and holds the teeth bone , os - rigid connective tissue that makes up the skeleton of vertebrates maxilla , maxillary , upper jaw , upper jawbone - the jaw in vertebrates that is fused to the cranium alveolar arch - the part of the upper or lower jawbones in which the teeth are set alveolar process , alveolar ridge , gum ridge - a ridge that forms the borders of the upper and lower jaws and contains the sockets of the teeth skull - the bony skeleton of the head of vertebrates chop - a jaw; "I'll hit him on the chops" 2. jaw - the bones of the skull that frame the mouth and serve to open it; the bones that hold the teeth face , human face - the front of the human head from the forehead to the chin and ear to ear; "he washed his face"; "I wish I had seen the look on his face when he got the news" feature , lineament - the characteristic parts of a person's face: eyes and nose and mouth and chin; "an expression of pleasure crossed his features"; "his lineaments were very regular" 3. jaw - holding device consisting of one or both of the opposing parts of a tool that close to hold an object alligator clip , bulldog clip - a clip with a spring that closes the metal jaws chuck - a holding device consisting of adjustable jaws that center a workpiece in a lathe or center a tool in a drill holding device - a device for holding something pair of pliers , pliers , plyers - a gripping hand

What is a beaver's home called?

Beavers, Beaver Pictures, Beaver Facts - National Geographic Size relative to a 6-ft (2-m) man Please add a "relative" entry to your dictionary. Beavers are famously busy, and they turn their talents to reengineering the landscape as few other animals can. When sites are available, beavers burrow in the banks of rivers and lakes. But they also transform less suitable habitats by building dams. Felling and gnawing trees with their strong teeth and powerful jaws, they create massive log, branch, and mud structures to block streams and turn fields and forests into the large ponds that beavers love. Domelike beaver homes, called lodges, are also constructed of branches and mud. They are often strategically located in the middle of ponds and can only be reached by underwater entrances. These dwellings are home to extended families of monogamous parents, young kits, and the yearlings born the previous spring. Beavers are among the largest of rodents. They are herbivores and prefer to eat leaves, bark, twigs, roots, and aquatic plants. These large rodents move with an ungainly waddle on land but are graceful in the water, where they use their large, webbed rear feet like swimming fins, and their paddle-shaped tails like rudders. These attributes allow beavers to swim at speeds of up to five miles (eight kilometers) an hour. They can remain underwater for 15 minutes without surfacing, and have a set of transparent eyelids that function much like goggles. Their fur is naturally oily and waterproof. There are two species of beavers, which are found in the forests of North America, Europe, and Asia. These animals are active all winter, swimming and foraging in their ponds even when a layer of ice covers the surface.

Which tissue carries sugary sap around the plant?

Transport in Plants Transport in Plants Carbon Fixation by Roots The main source of carbon for plants comes from the atmosphere as carbon dioxide and fixation of this carbon dioxide by leaves and other green parts of the shoot system in the presence of light as an energy source - the process of photosynthesis . Some of this fixed carbon is converted into fuels for respiration, such as glucose, some is stored as compact materials like starch, and some is used in building blocks, such as proteins, nucelotides and phospholipids, to build the plant body. Fixation is an odd word, and one that stems all the way back to alchemy. It makes perfect sense, however, when you think of gases as mobile, with their molecules constantly moving around by diffusion due to their thermal kinetic energy. Fixation means to render less mobile, and was historically depicted by clipping the 'wings' of the gaseous or volatile substance (by converting it into a solid or non-volatile liquid, for example). However, it is a little known fact that roots can also fix carbon. Roots do not photosynthesise, however, and they fix carbon in the absence of light with the use of enzymes. Ordinarily roots only fix enough carbon for their own secretory activities, with the bulk of carbon fixation occurring in the shoot system. Root-fixed carbon is used, for example, to produce root secretions which leak into the soil around the roots (the rhizosphere). These secretions probably have various functions, but appear to encourage plant-friendly microbes, signaling to mycorhizal fungi, for example, advertising the root and encouraging the fungus to form a symbiosis with it. These secretions are also thought to be important in helping to 'mobilise, plant nutrients - many nutrients are locked onto soil particles in an insoluble form and so can not be absorbed by  the roots until they have been dissolved or mobilised. In some herbaceous plants, it has been shown that roots can fix enough surplus carbon to contribute to shoot carbon, that is the roots export carbon that they fix and which is in excess of their own needs, into the shoot system. To what extent the roots contribute to the stem carbon of woody plants is not known. The Role of Root Pressure As well as contributing a small amount to the pressure gradient which drives xylem sap part-way up a tree, or perhaps to the top of some short plants, or even small trees, in certain conditions, root pressure possibly has several important functions. In very humid climates where evapotranspiration is too low to drive xylem flow, root pressure ensures that some xylem travels up the plant to deliver mineral nutrients from the roots to the shoot system. This root pressure may cause droplets of water to exude from vessels at the edges and tips of leaves (guttation) and some plants have special pores (hydathodes) at the ends of the veins to allow this water out (after the minerals are extracted from it by the cells). This flow due to root pressure also occurs in many plants at night, contributing to early morning due. It is also important in very early spring, supplying growing buds with minerals before the leaves have opened enough for evapotranspiration to take over as the main driving force. Root pressure may also help unblock cavitated vessels. Sugar in the Xylem In maples and birches, cold-tolerant trees, xylem sap is driven up the stem in winter and carries sucrose with it to fuel the developing flowers which open early before the leaves. The sucrose is loaded into the xylem from ray parenchyma and other storage cells in the xylem. This sap ascent can not be utilising the transpiration stream as no leaves are available in winter to drive it.  It occurs on warmer days that follow cold nights and is thought to involve a night-freeze, warm-day cycle of pressure changes in the trunk. At night the xylem sap freezes and this is thought to trap and compress gases in the xylem as the sap freezes. The daytime heat melts the ice in the xylem, expanding the trapped gases and generating a positive pressure to drive xylem sap flow up t

Which cells form the middle layer of plant leaves?

Leaf Structure, Function, and Adaptation About Watch and Favorite Watch Watching this resources will notify you when proposed changes or new versions are created so you can keep track of improvements that have been made. Favorite Favoriting this resource allows you to save it in the “My Resources” tab of your account. There, you can easily access this resource later when you’re ready to customize it or assign it to your students. Leaf Structure, Function, and Adaptation Leaves have many structures that prevent water loss, transport compounds, aid in gas exchange, and protect the plant as a whole. Learning Objective Describe the internal structure and function of a leaf Key Points The epidermis consists of the upper and lower epidermis; it aids in the regulation of gas exchange via stomata. The epidermis is one layer thick, but may have more layers to prevent transpiration . The cuticle is located outside the epidermis and protects against water loss; trichomes discourage predation. The mesophyll is found between the upper and lower epidermis; it aids in gas exchange and photosynthesis via chloroplasts . The xylem transports water and minerals to the leaves; the phloem transports the photosynthetic products to the other parts of the plant. Plants in cold climates have needle-like leaves that are reduced in size; plants in hot climates have succulent leaves that help to conserve water. Terms Full Text Leaf Structure and Function The outermost layer of the leaf is the epidermis. It consists of the upper and lower epidermis, which are present on either side of the leaf. Botanists call the upper side the adaxial surface (or adaxis) and the lower side the abaxial surface (or abaxis). The epidermis aids in the regulation of gas exchange. It contains stomata, which are openings through which the exchange of gases takes place. Two guard cells surround each stoma , regulating its opening and closing. Guard cells are the only epidermal cells to contain chloroplasts. The epidermis is usually one cell layer thick. However, in plants that grow in very hot or very cold conditions, the epidermis may be several layers thick to protect against excessive water loss from transpiration. A waxy layer known as the cuticle covers the leaves of all plant species . The cuticle reduces the rate of water loss from the leaf surface. Other leaves may have small hairs (trichomes) on the leaf surface. Trichomes help to avert herbivory by restricting insect movements or by storing toxic or bad-tasting compounds. They can also reduce the rate of transpiration by blocking air flow across the leaf surface . Trichomes give leaves a fuzzy appearance as in this (a) sundew (Drosera sp.). Leaf trichomes include (b) branched trichomes on the leaf of Arabidopsis lyrata and (c) multibranched trichomes on a mature Quercus marilandica leaf. Below the epidermis of dicot leaves are layers of cells known as the mesophyll, or "middle leaf." The mesophyll of most leaves typically contains two arrangements of parenchyma cells: the palisade parenchyma and spongy parenchyma . The palisade parenchyma (also called the palisade mesophyll) aids in photosynthesis and has column-shaped, tightly-packed cells. It may be present in one, two, or three layers. Below the palisade parenchyma are loosely-arranged cells of an irregular shape. These are the cells of the spongy parenchyma (or spongy mesophyll). The air space found between the spongy parenchyma cells allows gaseous exchange between the leaf and the outside atmosphere through the stomata. In aquatic plants, the intercellular spaces in the spongy parenchyma help the leaf float. Both layers of the mesophyll contain many chloroplasts. (a) (top) The central mesophyll is sandwiched between an upper and lower epidermis. The mesophyll has two layers: an upper palisade layer and a lower spongy layer. Stomata on the leaf underside allow gas exchange. A waxy cuticle covers all aerial surfaces of land plants to minimize water loss. (b) (bottom) These leaf layers are clearly visible in the scanning electron micrograph. The numerous small

Which antipodean bird is the largest member of the kingfisher family?

ANIMAL Teachers: Winged Ones: Kookaburra ANIMAL Teachers KOOKABURRA Resolving Family Issues The Kookaburra of Australia is the largest member of the Kingfisher Family. Unlike other members of the Kingfisher Family, Kookaburra lives in woodlands instead of near wetlands. Perched on a tree branch to spot prey, Kookaburra will swoop down and seize a tasty Insect in his long, dagger-like bill. Instead of Fish, Kookaburra eats Insects, Worms, and Reptiles. Known for his distinctive call, Laughing Kookaburra will sing in a loud chorus, �Koo-koo-koo-koo-koo-koo-kaa-kaa-kaa�. Blue-winged Kookaburra sings a coarser call that ends abruptly. Some people have described Kookaburra�s call as a rollicking laugh. What is strange about Kookaburra�s call is how many people are familiar with it, without knowing. American filmmakers often feature Kookaburra�s laugh as background noise for jungle scenes. What makes Kookaburra unusual is his family life. When his Young are fledged, They remain with their Parents to help raise the next group of Siblings. Kookaburra Brothers and Sisters will raise the second brood, while Parent Kookaburras raise the third brood. If one of the Parents dies, the Children continue to help the other Parent raise the rest of the Family. What people can learn from Kookaburra is how to be a good family member. Kookaburra can teach you how to resolve many family issues. Learn from Kookaburra what makes for a strong family. Important Kookaburra Teaching: Laughter and Joy �He has a distinctive laughing call that when heard makes one feel like laughing along with him. Stirring the joy that lives deep within your being. When you hear a Kookaburra remember to allow yourself to laugh, for laughter and joy are the very essence of our being.� Copyright: �Wisdom of Australian Animals�, Ann Williams-Fitzgerald. Kookaburra�s Teachings Also Include �A silent Kookaburra is a far more uplifting sign than the raucous laughter emanated by a chorus of mockery and taunt.� Copyright: �Animal Messengers�, Scott Alexander King. Kookaburra�s Wisdom Includes: Strong Families

Which microscopic organisms form the basis of marine and freshwater food chains?

Food Chains and Webs | Teaching Great Lakes Science Teaching Great Lakes Science Search Food Chains and Webs All living organisms depend on one another for food. By reviewing the relationships of organisms that feed on one another, this lesson explores how all organisms— including humans—are linked. If students understand the relationships in a simple food chain, they will better understand the importance and sensitivity of these connections, and why changes to one part of the food chain almost always impact another. Grade level: 4-8th grades Performance Expectations: MS-LS2-1 Ecosystems: Interactions, Energy and Dynamics. Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem. MS-LS2-2 Ecosystems: Interactions, Energy and Dynamics. Construct an explanation about how the different parts of the food chain are dependent on each other. MS-LS2-3 Ecosystems: Interactions, Energy and Dynamics. Develop a model to describe the cycling of matter and flow of energy among living parts of the food chain. MS-LS2-4 Ecosystems: Interactions, Energy and Dynamics. Construct an argument, supported by evidence gathered through observation and experience, showing how changes to physical or biological components of an ecosystem affect populations. MS-LS2-5 Ecosystems: Interactions, Energy and Dynamics. Evaluate competing design solutions for maintaining biodiversity and ecosystem services. MS-ESS3-3 Earth and Human Activity. Answer questions about how pollution affects food chains by applying scientific principles to design a monitoring plan for minimizing the human impact on the environment. For alignment, see: NGSS Summary Lesson Objectives Describe the difference between herbivores, carnivores and producers. Answer questions about the interdependence of herbivores, carnivores and producers as members of a food chain. Answer questions about how pollution affects food chains.   Background A food chain is a simplified way to show the relationship of organisms that feed on each other. It’s helpful to classify animals in a simple food chain by what they eat, or where they get their energy. Green plants, called producers, form the basis of the aquatic food chain. They get their energy from the sun and make their own food through photosynthesis. In the Great Lakes, producers can be microscopic phytoplankton (plant plankton), algae, aquatic plants like Elodea, or plants like cattails that emerge from the water’s surface. Herbivores, such as ducks, small fish and many species of zooplankton (animal plankton) eat plants. Carnivores (meat eaters) eat other animals and can be small (e.g., frog) or large (e.g., lake trout). Omnivores are animals (including humans) that eat both plants and animals. Each is an important part of the food chain. In reality, food chains overlap at many points — because animals often feed on multiple species — forming complex food webs. Food web diagrams depict all feeding interactions among species in real communities. These complex diagrams often appear as intricate spider webs connecting the species. This lesson demonstrates that changes in one part of a food chain or web may affect other parts, resulting in impacts on carnivores, herbivores, and eventually on producers. An example of this might be the harmful effects of pollution. The point that should be made is that when something disrupts a food web, humans should try to understand and minimize the disturbance. Students should also come to recognize that humans, too, are part of this complex web of life.   Food Chains and Food Webs – Parts and Pieces Food Chains Producers Plants form the base of Great Lakes food chains. They’re called producers, because they make their own food by converting sunlight through photosynthesis. They also act as food, providing energy for other organisms. In the Great Lakes, most producers are phytoplankton, or microscopic floating plants. An example of phytoplankton is green algae. Large rooted plants, another type of producer, provide food and she

Which bird feeds with its head upside-down and its beak held horizontally beneath the water?

Nature: Tickled pink by flamingo's visit - Houston Chronicle Nature: Tickled pink by flamingo's visit WONDERS OF NATURE By Gary Clark Published 5:30 am, Friday, May 28, 2004 Few birds have attracted as much public attention as the flamingo in Galveston Bay next to the Texas City Dike . But the question on everybody's mind, from hard-core birders to casual observers, is where did it come from? Decked out in pink plumes with a swanlike long neck and angular beak, the bird is called a greater flamingo (Phoenicopterus ruber) of the Caribbean variety. It normally congregates in large flocks at the Yucatán Peninsula and throughout the Caribbean and Bahamas down to northern South America. So what is a lone flamingo doing in Texas City? What it's doing right now is feeding on little marine organisms and putting on quite a show for spectators. Whether it's a wild bird is an unanswered question. Is it a captive flamingo that escaped from a zoo or water garden, or did it wander up to Texas from a wild Caribbean population? An answer will come from the Texas Bird Records Committee , a standing committee of the Texas Ornithological Society that analyzes reports of birds considered rare in Texas. A greater flamingo is certainly rare in Texas and anywhere in the United States. "The TBRC will primarily use two criteria to decide about the potential origin of the flamingo," said Mark Lockwood , the committee's secretary. "First is the condition of the bird, including its plumage, legs and beak. Captive birds often show signs of feather wear and can have damaged legs and beaks. Second is information from local aviculturists to make sure a captive bird didn't escape." The committee may have a decision within three months, after poring over photographs and written documentation by birders. To date, the committee has accepted into the record only four sightings of a wild flamingo. Those were from 1978 to 2001, south along the coast from Calhoun County to Kleberg County. The Texas City flamingo could become the first accepted record for the upper Texas Coast. Local expert birders believe it probably originated from a wild population. "I think the bird is wild because it is full-winged and doesn't appear to have been pinioned as are birds in captivity," said Dr. Dan Books , curator of vertebrate zoology at the Houston Museum of Natural Science . "Also, most captive birds in Houston are usually the Chilean or African flamingos, but this one is the Caribbean form of a greater flamingo." Dwight Peake of NASA notes that there is a large breeding colony of Caribbean flamingos on the northern Yucatán Peninsula. "Since flamingos often disperse after the nesting period, there's a good chance the flamingo came up on the recent strong southeasterly winds," he said. The bird at the Texas City Dike offers one of the best chances to see a potential wild flamingo in North America. To find it, drive onto the dike about a half mile to a pull-out on the left where volunteers from Galveston Audubon will show you the bird in spotting scopes. The greater flamingo strikes a handsome figure at nearly 5 feet tall, wading like a human angler but with less effort, in the shallows of the bay off the dike. It has characteristically thin pinkish legs, pinkish feathering, black flight feathers, and a beak grading from bone-color at the base to pale yellow in the middle and black at the end. The beak, which looks like a large sickle, is one way to distinguish a flamingo from the similarly pink-plumaged roseate spoonbills that reside on the Texas coast all year. Spoonbills have a spatula-shaped beak, and don't have the long, S-shaped sinewy neck of a flamingo. The Texas City flamingo looks like a young bird in its second year based on patterns such as a gray, scrawny neck and scapular feathers molting from white to pink. Flamingos take four years to acquire adult plumage. A characteristic pose of a flamingo at rest is its statuesque stance on one leg, a pose often exhibited by the Texas City bird. Otherwise, it spends its time sashaying through the water, stopping here and

What kind of a tongue does the okapi have?

Okapi (Okapia Johnstoni) - Animals - A-Z Animals Five groups that classify all living things Animalia A group of animals within the animal kingdom Chordata A group of animals within a pylum Mammalia A group of animals within a class Artiodactyla A group of animals within an order Giraffidae A group of animals within a family Okapia Comprised of the genus followed by the species Okapia johnstoni Most widely used name for the species Okapi The domestic group such as cat or dog Mammal The specific area where the animal lives Dense mountain rainforest The colour of the animal's coat or markings Red, Brown, Black, White The protective layer of the animal Fur How long (L) or tall (H) the animal is 1.5m - 2m (4.9ft - 6.5ft) The measurement of how heavy the animal is 200kg - 300kg (440lbs - 660lbs) The fastest recorded speed of the animal 60kph (37mph What kind of foods the animal eats Herbivore The food that the animal gains energy from Leaves, Shoots, Fruit Other animals that hunt and eat the animal Leopard, Serval, Human Whether the animal is solitary or sociable Diurnal How long the animal lives for 20 - 30 years The average number of babies born at once 1 The likelihood of the animal becoming extinct Near Threatened Horizontal white stripes on rear and legs Fun Fact: Eats more than 100 different types of plant! Okapi Location Okapi Okapi Classification and Evolution The Okapi is an elusive herbivore that is found in a small pocket of tropical mountain forest in central Africa . Despite it's Deer-like appearance the Okapi is actually one of the last remaining ancestors of the Giraffe , which is the tallest animal on Earth. Along with having a relatively long neck compared to it's body size , the most striking feature of the Okapi is the horizontal stripes that are particularly visible on their behinds and give this animal an almost Zebra-like appearance. The Okapi is very shy and secretive, so much so in fact that they were not recognised as a distinct species by western science until the earth 20th century. Although they are seldom seen by people, the Okapi is not an endangered species as they are thought to be fairly common in their remote habitats. Okapi Anatomy and Appearance Like it's distant and much larger ancestor, the Okapi has a long neck which not only helps it to reach leaves that are higher up, but also provides the Okapi with a tool to both defend itself and it's territory . The Okapi has a red-brown coloured coat of fur with horizontal, white striped markings that are found on their hind quarters and at the tops of their legs, and provide the Okapi with excellent camouflage in the dense jungle. They have white ankles with a dark spot above each hoof and very thick skin to help protect them from injury. The Okapi has a long head and dark muzzle with large set-back ears which enable the Okapi to detect approaching predators easily. The Okapi also has an impressively long tongue, which is not only black in colour but it is also prehensile meaning that it is able to grab hold of leaves from the branches above. Okapi Distribution and Habitat The Okapi is found in the dense tropical rainforests of north-eastern Democratic Republic of Congo generally at an altitude that can vary between 500 and 1,000 meters, although the majority of individuals are thought to inhabit areas at roughly 800 meters above sea level. They are incredibly shy and elusive animals and rely heavily on the very thick foliage around them to protect them from being spotted by predators . The Okapi can also be found in areas where there is a slow-moving fresh water source, but the range of the Okapi is very much limited by natural barriers, with unsuitable habitats on all four sides trapping these animals into the 63,000 square kilometre Ituri Rainforest . Around a fifth of the rainforest is today made up of the Okapi Wildlife Reserve, which is a World Heritage Site. Although they are thought to be common in their native region, the Okapi has been severely threatened by habitat loss particularly from deforestation. Okapi Behaviour and Lifestyle The

What do baleen whales eat?

Diet & Eating Habits Food Preferences And Resources In general, baleen whales feed low on the food chain, primarily eating zooplankton and small fishes, which they encounter in large swarms or schools. Right whales eat zooplankton (animal plankton). Their finely fringed baleen is able to strain from the water copepods (a type of small crustacean) and other small zooplankton. Krill (a family of small, shrimplike crustaceans) and copepods are major components of a right whale's diet. Rorquals generally eat larger prey than do right whales. Depending on species, they eat a variety small crustaceans, squids, and small schooling fishes. Blue whales eat mostly krill. Fin whales eat krill, copepods, squids, and variety of small schooling fishes. Humpback whales, Bryde's whales, and minke whales prey mostly on krill and small schooling fishes. Minke whales in the northern hemisphere prey mostly on small schooling fishes; those in the southern hemisphere prey mostly on krill. Sei whales eat copepods, krill and amphipods (another type of small crustacean). In the North Pacific and North Atlantic Oceans they also eat squids and small schooling fishes. Gray whales eat mainly invertebrates that live in bottom sediments, mostly amphipods and probably marine worms. It's likely that some whales' diets depend on food availability. Food Intake Most baleen whales spend about four to six months in the summer feeding intensively in high-latitude, productive waters. They spend the next six to eight months traveling and breeding. Scientists estimate that large baleen whales eat about 4% of their body weight each day during the feeding season. Food intake during the feeding season exceeds daily requirements, and excess energy is stored as fat, much of it in the blubber. A blue whale eats up to 3,600 kg (8,000 lb.) of krill each day for about 120 days. It is estimated to take 1,000 kg (2,200 lb.) of food to fill a blue whale’s stomach. Gray whales eat about 150,000 kg (340,000 lb) of food during a 130 to 140 day feeding period - a daily average intake of about 1,089 kg (2,400 lb.). It is estimated to take 300 kg (660 lb.) of food to fill a gray whale's stomach. Gray whales gain about 16% to 30% of their total body weight during a feeding season. Throughout the traveling and breeding season, baleen whales eat much less or not at all. Blubber gained during the feeding season sustains the whale during the winter months. A baleen whale's thick blubber layer stores fat; it is an energy reserve that is necessary during the traveling and breeding seasons. Winter daily feeding rate is only about 0.4% of body weight. Blubber makes up 27% of a blue whale's body weight, 23% of a fin whale, 21% of a sei whale, 29% of a gray whale, and 36% to 45% of a right whale. Method Of Collecting And Eating Food A right whale "grazes" by swimming slowly through swarms of small zooplankton (animal plankton) with its mouth open. At the surface this has been termed "skim-feeding", but right whales also feed under water. Water - and zooplankton - enter a right whale's mouth through a gap in the front baleen plates. Zooplankton is caught in the finely fringed baleen mat; water flows through the baleen and out the sides of the mouth. With long baleen plates and a huge mouth, right whales are adapted for straining immense amounts of food. Right whales usually feed singly, but a group of whales may swim and feed in a V-formation. Rorqual whales feed by gulping enormous mouthfuls of prey and water. As its mouth fills, a rorqual's throat grooves expand and its mouth cavity balloons outward. Then the whale brings its jaws together and contracts the throat grooves, forcing water out. Prey such as krill and small fishes are caught in the baleen mat as water is forced through the baleen and out the sides of the mouth. Rorquals may feed at the surface or deeper in the water. Humpback whales have been observed blowing "bubble nets" to help them feed. The whale dives down, then swims up in a spiral while releasing bubbles of air from its blowholes. The bubbles float up in a column, keep

Which South American vulture can have a wing span of up to 3 meters and a body weight of up to 13 kilos?

Vulture | San Diego Zoo Animals & Plants San Diego Zoo Animals & Plants FAMILIES: Cathartidae (New World) and Accipitridae (Old World) GENERA: 14 SPECIES: 23 ABOUT What makes a vulture? They may not be the prettiest birds of prey, but the world would be a smellier place without vultures!  All vultures have a wide wingspan, which allows them to soar for long periods of time without flapping so much as a feather while looking for carrion to eat. They all have a sharp, hooked beak for ripping apart meat. Vultures are large compared to other birds. Their bald head and neck serve a useful purpose, allowing vultures to steer clear of infection and tangled feathers when eating decaying meat. A strong immune system allows vultures to eat rotting and possibly infected meat without getting sick. These unusual birds are divided into two groups: New World vultures, which are from North, Central, and South America; and Old World vultures, which live in Africa, Asia, and Europe. New World vultures have a distinctive bald head, an adaptation that helps reduce the risks of disease, because bacteria could become lodged in feathers, while the bald head and neck may be disinfected by the sun’s rays. New World vultures have nostrils that are long and horizontal, with a space between them. They do not have a voice box, so they cannot make any sound except hisses and grunts. New World vultures don’t build nests; instead, they lay their eggs in holes on high rocky surfaces or in tree cavities.  Some examples of New World vultures are turkey vultures, black vultures, king vultures,  California condors , and  Andean condors .  Old World vultures look like their eagle and hawk relatives. They have large, grasping talons, a voice box to vocalize with, and build nests made of sticks on rocky platforms or in trees. Old World vultures have also been around longer than the New World vultures. They have stronger feet than the New World vultures, which have feet that are not designed for grasping, and large, broad wings that allow them to stay aloft for most of the day, and a large, powerful beak with a hooked tip.  Some other examples of Old World vultures are Himalayan, Egyptian, hooded, Indian black, and palm-nut vultures, and Egyptian or Eurasian griffons. Although New World vultures are unable to make more than hissing and grunting sounds, Old World vultures can be quite vocal when feeding at a carcass, making lots of grunts, croaks, screeches, and chatter. White-backed vultures croak plaintively or squeal like pigs during a meal. Bearded vultures scream while rolling and twisting in flight during courtship. Not many animals threaten vultures. Covered as they are with bacteria, they would make most predators sick if eaten. Other scavengers may threaten the vulture, mainly to get better access to a shared carcass. Vultures tend to gorge themselves, often to the point of being unable to fly. If they feel bothered as they stand about digesting their food, they simply regurgitate to lighten the load and fly off. Many people look at the vulture as a sign of death, but some cultures admire the birds. Ancient Egyptians connected the Egyptian griffon to their goddess Nekhbet, guardian of mothers and children. Griffon images are found in early Egyptian paintings and drawings and even had a place on the crown of the pharaoh, alongside the cobra. In Native American culture, California condors are important in mythology and burial rituals.  Vultures are also important in India, as they help remove dead animals without spreading disease. In other parts of Asia, religious and cultural traditions call for the carcasses of domestic animals to be left out for “disposal” by vultures. In some regions, even human remains are left out for the vultures prior to burial.  Vultures may not have the cleanest job, but you will never hear them complaining! HABITAT AND DIET Home is where the food is! Vultures are pretty flexible when it comes to their habitat, as long as there is food, although you won’t find them in Australia, polar regions, or most small islands. They are pr

Which part of a beetle's body is a skeleton?

Insect Parts - Elementary Science Lessons & Tests - My Schoolhouse - Online Learning   There are many kinds of insects.  They may all look different, but they are alike.  They are alike in three ways. six legs three main body sections (head, thorax, and abdomen) hard skeleton One way all insects are alike is that they have six legs.  Three legs on each side of the body.  The legs are attached to the thorax.  The thorax is the middle part of an insect's body.  Many insects have wings that are attached to the thorax. Behind the thorax is the abdomen.  It is usually the largest part of an insect. In front of the thorax is the head.  Eyes and a mouth are located in the head.  Antennae or feelers are also found on the head.  These are used to smell, feel, and taste things. Insects have a skeleton too!  Their skeleton is on the outside of their bodies.  It is called an exoskeleton.  Your skeleton is found inside your body, and it is made of bones.  An insect's skeleton is the hardest part of its body.  It is made of a material called chitin. Directions: Answer the questions about insects. How many legs do all insects have? two

What is the name of the structures which allow leaves to breathe?

The Open Door Web Site : Biology : How Plants Breathe : The Differences in the Exchange of Gases between Plant Respiration and Photosynthesis Remember that a green plant respires all the time, day and night. A green plant photosynthesizes only in the presence of sunlight.   All parts of the plant respire, the leaves, the stem, the roots and even the flowers. The parts above the soil get their oxygen directly from the air through pores. The pores in the leaves are called stomata (singular: stoma). The pores in the branches of trees are called lenticels.     The drawing shows a leaf of a ficus plant. A small part of the underside of the leaf has been magnified to show the stomata. The average number of stomata per mm2 of leaf is around 300. The smallest number is found on Tradescantia leaves which have 14 per mm2 . The highest number of stomata is found on the leaves of the Spanish oak tree. Here there are around 1200 per mm2 . The roots of a plant also need oxygen which they obtain from the air spaces in the soil. If you give too much water to a plant in a pot you could kill the roots by drowning them! Plants, such as rice, which normally grow in wet soil often have air spaces in their roots. This is so that they can carry air from the atmosphere down to the root tips to be able to respire under water.   The Open Door Web Site is non-profit making. Your donations help towards the cost of maintaining this free service on-line. Donate to the Open Door Web Site using PayPal © The Open Door Team 2017 Any questions or problems regarding this site should be addressed to the webmaster © Paul Billiet and Shirley Burchill 2017

Which sub-division of plants is named after their practice of forming 'naked seeds'?

plant reproduction Capsule at the top of the sporophyte forms haploid (1n) spores Sexual reproduction in Moss: Moss produce 2 kinds of jacketed gametes --- eggs & sperm Egg producing organ is called the archegonium Eggs are larger and nonmotile Sperm producing organ is called the antheridium Sperm are smaller, flagellated cells Antheridia & archegonia are both part of the gametophyte plant Fertilization can occur only during or soon after RAIN  when the gametophyte is covered with Water Sperm swim to the egg by following a trail of chemicals released by the egg in the water Fertilization produces a zygote that becomes a sporophyte Mature sporophytes produce homosporous spores (all the same type) Mature capsules open & release spores spread by wind Spores landing on moist places germinate into protonema that become new gametophytes   Small pieces may break off from a gametophyte & become a new plant (fragmentation) Small buds called gemmae may be washed off by rain and develop new moss plants Fern Characteristics & Life Cycle: Goes through alternation of generations  Sporophyte phase is the dominant stage Fern gametophytes are small, flat plants anchored to the soil by root-like rhizoids Antheridia & archegonia form on the underside of fern gametophytes Sperm swim to egg through water droplets to form zygote (fertilized egg) Zygotes form new sporophytes with roots, stems, & leaves Spore cases called sori form on the underside of fern fronds (leaves) Ferns are homosporous (single type of spore formed)   New fronds form from an underground stem called the rhizome Vascular tissue carries nutrients & water between the parts of the fern Fronds are compound leaves attached by a short stalk called the stipe to the underground stem or rhizome Immature fronds or fiddleheads are coiled   Characteristics & Life Cycle of Conifers: Called gymnosperms Have naked seeds that develop on scales of the female cones Sporophyte is the dominant stage Adapted to cooler climates Called evergreens (pine, cedar, spruce, fir...) Giant Redwood is one of the Earth's largest organisms Bristlecone Pines are the oldest living organisms (some more than 5000 years old) Giant Redwood The pine life cycle takes 2-3 years from the formation of cones until seeds are released Female cones have spirally-arranged scales with ovules at their base Female cones produce sticky resin Ovules contain an egg that will develop into a seed  Male cones produce large amounts of pollen in the spring that is spread by wind to the female cones Resin traps the pollen so pollination can occur A tube from the pollen grain takes a year to grow to the ovule so a sperm can fertilize the egg and form seeds Angiosperms or Flowering Plants: Bright colors, attractive shapes, and fragrant aromas help flowering plants attract their pollinators (insects, birds, mammals...) Flowers without bright colors and pleasing odors are usually wind or water pollinated (grasses) Called angiosperms Flowers, the reproductive part of a plant,  have a swollen base or receptacle to attach to the stem Flowers have 4 whorls (modified leaves) attached to the receptacle --- petals, sepals, pistils, and stamen Pistils (innermost whorl) are the female part of the flower, while Stamens are the male part Sepals (outermost whorl) are found below the petals and may look leaf-like (some may be the same color as petals) Sepals enclose the flower bud before it opens  Sepals are collectively called the calyx Petals are often colorful to attract pollinators Petals are collectively called the corolla Monocot flower parts are arranged in multiple of THREES, while dicots are in multiples of FOUR or FIVE Perfect flowers have both stamens & pistils (rose) Imperfect flowers are either a male (pistillate) or female (staminate) flower (pumpkin or melons) Some angiosperms have both male & female flowers on the SAME plant (monoecious) Othe

What is the state of inactivity through the dry, summer season, as hibernation is the dormancy of the winter months?

Hibernation | Article about hibernation by The Free Dictionary Hibernation | Article about hibernation by The Free Dictionary http://encyclopedia2.thefreedictionary.com/hibernation Also found in: Dictionary , Thesaurus , Medical , Wikipedia . hibernation (hī'bərnā`shən) [Lat.,= wintering], practice, among certain animals, of spending part of the cold season in a more or less dormant state, apparently as protection from cold when normal body temperature cannot be maintained and food is scarce. Hibernating animals are able to store enough food in their bodies to carry them over until food is again obtainable. They do not grow during hibernation, and all body activities are reduced to a minimum: there may be as few as one or two heartbeats a minute. Cold-blooded animals (e.g., insects, reptiles, amphibians, and fish) must hibernate if they live in environments where the temperature—and hence their own body temperature—drops below freezing. Some insects pass their larval stage in a state of hibernation; in such cases hibernation is closely associated with the reproductive cycle (see larva larva, independent, immature animal that undergoes a profound change, or metamorphosis, to assume the typical adult form. Larvae occur in almost all of the animal phyla; because most are tiny or microscopic, they are rarely seen. They play diverse roles in the lives of animals. ..... Click the link for more information. ; pupa pupa , name for the third stage in the life of an insect that undergoes complete metamorphosis, i.e., develops from the egg through the larva and the pupa stages to the adult. ..... Click the link for more information. ). However, most warm-blooded animals, i.e., birds and mammals, can survive freezing environments because their metabolism controls their body temperatures. Many hibernating animals seek insulation from excessive cold; bears and bats retire to caves, and frogs and fish bury themselves in pond bottoms below the frost line. Analogous to hibernation is aestivation, a dormant period of escape from heat and drought. Other methods of avoiding excessively high or low temperatures and destructive increases or decreases in the water supply are encystment and ensuing dormancy, e.g., in plant seeds and bacteria, and migration. Some animals, such as rabbits, raccoons, and squirrels, store food against scarcity and spend cold periods asleep in their burrows, though they may emerge on warm days. Hibernation A term generally applied to a condition of dormancy and torpor found in cold-blooded (poikilotherm) vertebrates and invertebrates. (The term is also applied to relatively few species of mammals and birds, which are warm-blooded vertebrates.) This rather universal phenomenon can be readily seen when body temperatures of poikilotherm animals drop in a parallel relation to ambient environmental temperatures. Poikilotherm animals Hibernation occurs with exposure to low temperatures and, under normal conditions, occurs principally during winter seasons when there are lengthy periods of low environmental temperatures. A related form of dormancy is known as estivation. Many animals estivate when they are exposed to prolonged periods of drought or during hot, dry summers. For all practical purposes, hibernation and estivation in animals are indistinguishable, except for the nature of the stimulus, which is either cold or an arid environment. There is no complete list of animals that hibernate; however, many examples can be found among the poikilotherms, both vertebrate and invertebrate. The poikilotherms are sometimes referred to as ectothermic, because their body temperatures are not internally regulated but follow the rise and fall of environmental temperatures. During hibernation and winter torpor, body temperatures reflect the environmental temperature, often to within a fraction of a degree. Among the classic examples of hibernators or estivators are reptiles, amphibians, and fishes among the vertebrates, and insects, mollusks, and many other invertebrates. For many ectothermic vertebrates (fishes, amphibians, and re

What kind of a creature is a scorpion?

Scorpions, Scorpion Pictures, Scorpion Facts - National Geographic Scientists aren't sure why, but scorpions are fluorescent under ultraviolet light. Size relative to a teacup: Scorpions are members of the class Arachnida and are closely related to spiders, mites, and ticks. They are commonly thought of as desert dwellers, but they also live in Brazilian forests, British Columbia, North Carolina, and even the Himalayas. These hardy, adaptable arthropods have been around for hundreds of millions of years, and they are nothing if not survivors. Survival Adaptations There are almost 2,000 scorpion species, but only 30 or 40 have strong enough poison to kill a person. The many types of venom are effectively tailored to their users' lifestyles, however, and are highly selected for effectiveness against that species' chosen prey. Scorpions typically eat insects, but their diet can be extremely variable—another key to their survival in so many harsh locales. When food is scarce, the scorpion has an amazing ability to slow its metabolism to as little as one-third the typical rate for arthropods. This technique enables some species to use little oxygen and live on as little as a single insect per year. Yet even with lowered metabolism, the scorpion has the ability to spring quickly to the hunt when the opportunity presents itself—a gift that many hibernating species lack. Such survival skills allow scorpions to live in some of the planet's toughest environments. Researchers have even frozen scorpions overnight, only to put them in the sun the next day and watch them thaw out and walk away. But there is one thing scorpions have a difficult time living without—soil. They are burrowing animals, so in areas of permafrost or heavy grasses, where loose soil is not available, scorpions may not be able to survive.

Which part of the common valerian is used to make a sedative?

Valerian — Health Professional Fact Sheet Disclaimer Key points This fact sheet provides an overview of the use of valerian for insomnia and other sleep disorders and contains the following key information: Valerian is an herb sold as a dietary supplement in the United States. Valerian is a common ingredient in products promoted as mild sedatives and sleep aids for nervous tension and insomnia. Evidence from clinical studies of the efficacy of valerian in treating sleep disorders such as insomnia is inconclusive. Constituents of valerian have been shown to have sedative effects in animals, but there is no scientific agreement on valerian's mechanisms of action . Although few adverse events have been reported, long-term safety data are not available. What is valerian? Valerian (Valeriana officinalis), a member of the Valerianaceae family, is a perennial plant native to Europe and Asia and naturalized in North America [ 1 ]. It has a distinctive odor that many find unpleasant [ 2 , 3 ]. Other names include setwall (English), Valerianae radix (Latin), Baldrianwurzel (German), and phu (Greek). The genus Valerian includes over 250 species , but V. officinalis is the species most often used in the United States and Europe and is the only species discussed in this fact sheet [ 3 , 4 ]. What are common valerian preparations? Preparations of valerian marketed as dietary supplements are made from its roots, rhizomes (underground stems), and stolons (horizontal stems). Dried roots are prepared as teas or tinctures , and dried plant materials and extracts are put into capsules or incorporated into tablets [ 5 ]. There is no scientific agreement as to the active constituents of valerian, and its activity may result from interactions among multiple constituents rather than any one compound or class of compounds [ 6 ]. The content of volatile oils , including valerenic acids ; the less volatile sesquiterpenes ; or the valepotriates ( esters of short-chain fatty acids ) is sometimes used to standardize valerian extracts. As with most herbal preparations, many other compounds are also present. Valerian is sometimes combined with other botanicals [ 5 ]. Because this fact sheet focuses on valerian as a single ingredient, only clinical studies evaluating valerian as a single agent are included. What are the historical uses of valerian? Valerian has been used as a medicinal herb since at least the time of ancient Greece and Rome. Its therapeutic uses were described by Hippocrates, and in the 2nd century, Galen prescribed valerian for insomnia [ 5 , 7 ]. In the 16th century, it was used to treat nervousness, trembling, headaches, and heart palpitations [ 8 ]. In the mid-19th century, valerian was considered a stimulant that caused some of the same complaints it is thought to treat and was generally held in low esteem as a medicinal herb [ 2 ]. During World War II, it was used in England to relieve the stress of air raids [ 9 ]. In addition to sleep disorders, valerian has been used for gastrointestinal spasms and distress , epileptic seizures, and attention deficit hyperactivity disorder . However, scientific evidence is not sufficient to support the use of valerian for these conditions [ 10 ]. What clinical studies have been done on valerian and sleep disorders? In a systematic review of the scientific literature , nine randomized , placebo-controlled , double-blind clinical trials of valerian and sleep disorders were identified and evaluated for evidence of efficacy of valerian as a treatment for insomnia [ 11 ]. Reviewers rated the studies with a standard scoring system to quantify the likelihood of bias inherent in the study design [ 12 ]. Although all nine trials had flaws, three earned the highest rating (5 on a scale of 1 to 5) and are described below. Unlike the six lower-rated studies, these three studies described the randomization procedure and blinding method that were used and reported rates of participant withdrawal . The first study used a repeated-measures design; 128 volunteers were given 400 mg of an aqueous extract of valer

What is the name of the structures which allow stems to breathe?

The Open Door Web Site : Biology : How Plants Breathe : The Differences in the Exchange of Gases between Plant Respiration and Photosynthesis Remember that a green plant respires all the time, day and night. A green plant photosynthesizes only in the presence of sunlight.   All parts of the plant respire, the leaves, the stem, the roots and even the flowers. The parts above the soil get their oxygen directly from the air through pores. The pores in the leaves are called stomata (singular: stoma). The pores in the branches of trees are called lenticels.     The drawing shows a leaf of a ficus plant. A small part of the underside of the leaf has been magnified to show the stomata. The average number of stomata per mm2 of leaf is around 300. The smallest number is found on Tradescantia leaves which have 14 per mm2 . The highest number of stomata is found on the leaves of the Spanish oak tree. Here there are around 1200 per mm2 . The roots of a plant also need oxygen which they obtain from the air spaces in the soil. If you give too much water to a plant in a pot you could kill the roots by drowning them! Plants, such as rice, which normally grow in wet soil often have air spaces in their roots. This is so that they can carry air from the atmosphere down to the root tips to be able to respire under water.   The Open Door Web Site is non-profit making. Your donations help towards the cost of maintaining this free service on-line. Donate to the Open Door Web Site using PayPal © The Open Door Team 2017 Any questions or problems regarding this site should be addressed to the webmaster © Paul Billiet and Shirley Burchill 2017

Which acid is contained in rhubarb leaves, making them poisonous to eat?

Are Rhubarb Leaves Poisonous? Make a Natural Insecticide with the Leaves. Many visitors ask, " Can rhubarb leaves be composted?  " It would stand to reason that if the leaves are poisonous, then adding them to compost would be a concern. However, since the oxalic acid is broken down, diluted and pH balanced quite quickly, this is not a concern. Since humans and animals do not normally ingest matter from a compost, rhubarb leaves should be able to be added safely to the compost. Go here for more information and tips for composting rhubarb leaves. Interestingly, the leaves of rhubarb can be used to make a natural insecticide. If you have a large rhubarb patch, you may be interested in making this natural insecticide using the leaves after picking your rhubarb.  A Recipe for Natural Insecticide Using Rhubarb Leaves Boil 500 grams of rhubarb leaves in a few pints of water for about 20 minutes. Allow leaf mixture to cool. Strain the liquid into a CHILD PROOF/SAFE suitable container. Add a tiny bit of dish detergent or soap flakes, (not laundry detergent). Using a spray bottle, spray on leaves to kill off bugs such as aphids and spider mites, June bugs, and fungus diseases. *NOTE - DO NOT spray this product on ANYTHING edible. Rhubarb leaves contain high amounts of oxalic acid, and are poisonous, and could cause death.   If you are interested in more recipes to make simple homemade Natural Pesticides and Insecticides, Go here Here are additional pages within this website that provide helpful information about growing rhubarb in the home garden (or use the website's navigation bars):

What kind of an organism causes a 'rust' attack on plants?

Fungal parasites of plants Home >> Where fungi grow >> Parasites >> Fungal parasites of plants FUNGAL PARASITES OF PLANTS The study of plant disease, plant pathology, is a large and important one. Many universities have entire departments of plant pathology. The importance of the subject is obvious; since the beginning of agriculture humans have had to endure major crop losses because of disease. Even today, when crop health is under careful scrutiny, disease may suddenly strike and ruin an entire season's growth. It happens every year in some part of the globe, even in so-called developed nations. Most plant diseases are caused by fungi; losses to bacteria and viruses are important, but less so than those caused by fungi. A great diversity of fungi cause plant disease, nearly all major groups are involved. In spite of these numbers there are just two types of parasite to consider: nectrotrophs and biotrophs. Necrotrophs are a little like predators; they kill the tissues they are about to consume before they eat them. Unlike predators, however, they don't normally kill the whole organism, just a part of it. They do this by means of toxins that diffuse out into the host tissues, killing the cells they encounter. The fungus then extends its hyphae into these killed areas and digests them. Biotrophs obtain their nutrition from living cells with which they may establish fairly long-lived associations. They usually penetrate the cell walls of their hosts and establish contact with the cell membrane by means of haustoria, cells specialized for the absorption of nutrients. Plants do not just accept parasitic fungi. They have a large array of defense mechanisms that guard against fungal disease so that most fungi cannot get in. These defenses include physical barriers like the tough cuticle lining the surfaces of plants or the bark on trees. Chemical barriers including various toxins and strong oxidizers may be utilized. Fungi in their turn have developed ways of circumventing these defenses and seem to be able to develop new ones as soon as the plant confronts them. Some scientists have referred to this as a biological arms race. Plants differ greatly from one another in how they resist disease. NECROTROPHS The plants in the photo at left are mainly blueberries but if you look closely you will also see chokeberries, raspberries and perhaps some other species. All are common in New Brunswick and are frequently infected by fungi. In this example the leaves are riddled with dead spots brought about by necrotrophic plant parasites. These range from small dark spots to larger dead areas, often ringed by discoloured dying zones. The fungi are within the spots, releasing toxins that kill the leaf cells and then spreading out into the killed areas. Necrotrophic parasites are not always easy to characterize. At times such infections may be caused by biotrophic parasites that make such large nutritional demands on their host that they kill parts of it and thus resemble a necrotroph. However, biotrophs do not produce lethal toxins and they do not feed on dead tissues. BIOTROPHS Because they do not produce toxins biotrophs may have longer and less damaging relationships with their hosts. In the figure at right the rust fungus Chrysomyxa ledi has formed several sites of sporulation on the underside of a leaf of Labrador tea. These areas of sporulation are confined within zones defined by veins. No yellowing or senescence of the host leaf due to this infection is visible although there appears to have been some damage from a necrotroph on the upper margin. DIVERSITY OF PLANT PARASITIC FUNGI Species of fungi causing plant disease can be found in nearly all taxonomic groups and will be encountered frequently in the section on classification . Instead we will examine diversity from a pathologist's point of view, focussing more on the disease than on the agent of the disease. Roots Plant roots are attacked by a great range fungi, from simple organisms parasitic on a single cell to ones attacking an entire root syste

Which is the dominant generation in the ferns?

moss & fern notes b1 The haploid gametophyte stage contains half the chromosome number & produces gametes (egg & sperm)  Gametophyte stage is dominant in the moss's life cycle Gametophytes are photosynthetic & have root-like rhizoids The diploid sporophyte has a complete set of chromosomes & produces spores by meiosis Sporophyte of a moss is smaller than, & attached to the Gametophyte Sporophytes lack chlorophyll & depend on the photosynthetic gametophyte for food Sporophyte has a long, slender stalk topped with a capsule Capsule forms haploid (n) spores  Moss Capsules Sexual Reproduction in Moss: Mosses produce 2 kinds of gametes (egg & sperm) Gametes of Bryophytes are surrounded by a jacket of sterile cells that keep the cells from drying out Female gametes or eggs are larger with more cytoplasm & are immobile Flagellated sperm must swim to the egg through water droplets for fertilization Moss gametes form in separate reproductive structures on the Gametophyte --- Archegonium & Antheridium Archegonium Each Archegonium forms one egg, but each Antheridium forms many sperm Fertilization can occur only after rain when the Gametophyte is covered with water Sperms swim to the egg by following a chemical trail released by the egg  A zygote (fertilized egg) forms that undergoes mitosis and becomes a Sporophyte Cells inside mature Sporophyte capsule undergoes meiosis and form haploid spores Haploid spores germinate into juvenile plants called protonema Protonema begin the Gametophyte generation Protonema Spores are carried by wind & sprout on moist soil forming a new Gametophyte Asexual reproduction in Mosses: Asexual reproduction in moss may occur by fragmentation or gemmae Pieces of a Gametophyte can break off & form new moss plants (fragmentation) Gemmae are tiny, cup shaped structures on the Gametophytes  Raindrops separate gemmae from the parent plant so they can spread & form new Gametophytes  Gemmae cups Serve as pioneer plants on bare rock or ground Help prevent erosion Alternates between dominant Sporophyte stage & Gametophyte stage Sporophyte stage has true roots, stems, & leaves Produce spores on the underside of leaves  Leaves are called fronds & are attached by a stem-like petiole FERNS Spores produced on underside of fronds in clusters of sporangia called sori Spores undergo meiosis, are spread by wind, & germinate on moist soil to form prothallus Prothallus begins the Gametophyte stage Mature Gametophytes are small, heart-shaped structures that live only a short time Male antheridia & female archegonia grow on the prothalli Sperm must swim to the egg to fertilize it & developing embryo becomes the Sporophyte generation Newly forming fronds are called fiddleheads & uncurl Uses for Ferns:

What is the name of the lustrous substance that forms pearl and mother-of-pearl?

Mother of Pearl Bracelet | zen jewelz zen jewelz – Mother of Pearl Bracelet MOTHER OF PEARL BRACELET: BLISS/ BEAUTY/ COMFORT & MORE! Mother of Pearl  bracelet: Mother of Pearl gets its name from the fact that it is the iridescent lining of shell, where pearls can grow. Shells are related significantly to the ocean, because they have been part of it for many years. The ocean brings feelings of well-being and relaxation, it arouses all of our senses. Wearing Mother of Pearl connects you to beauty, provides comfort, caring, delight, gentleness, love, peacefulness and solace. It is said to attract prosperity. It is used to heighten intuition, psychic sensitivity and imagination. It is said to protect from negative influence and transmute negative energy. Mother of Pearl tends to be highly protective and a particularly potent stone of protection for children. It also is known to purify environments. Mother of Pearl can bring harmony in relationships It can be especially useful for handling and calming emotional situations and be very soothing to the emotions. Wearing Mother of Pearl  healing crystal when working through an emotional situation with someone is said to be beneficial and promotes cooperation. It can assist with the easy flow of feelings and sensitivities to others. It can bring harmony in relationships. It is connected with family, in particular motherhood, which gives it the name “the mothering stone.” zen jewelz – Mother of Pearl Mother of Pearl Bracelet: Physical Healing Properties Mother of Pearl Bracelet: Crystal healing and folklore say that Mother of Pearl is helpful for high blood pressure, dizziness, improving vision, cataracts and wound healing. It can strengthen the immune system, muscle tissues and the heart. It is known to help with arthritis and joint disorders. It can relieve allergies, rashes and skin complaints. What is Mother of Pearl? Mother of pearl, also called  nacre , is an iridescent layer of material that forms the shell lining of many  mollusks . Pearl  oysters  and  abalone  are both sources of this substance, which is widely used as an inlay in jewelry, furniture, and musical instruments. Mother of pearl comes in several natural colors as seen here in cream and white. Mother of Pearl Shell Formation Two substances, one mineral and the other organic, combine to create mother of pearl. Tiny hexagonal plates of aragonite, a form of  calcium carbonate , are arranged in layers alternating with conchiolin, a flexible protein similar to  silk  that is secreted by the mollusk. Aragonite on its own is very brittle, but combined with the protein it forms a strong, flexible material that can withstand hard use. The mollusk first of all secretes a layer of conchiolin. Aragonite crystals then form on this surface at numerous points, growing until they meet each other to form tiny plates. A further layer of protein is then deposited and so on, so that over time, many layers build up. The resilience of pearls comes from its layered structure and the contrast in properties between the mineral and organic layers. The aragonite consists if hard, brittle crystals, while the organic protein layers are a natural  polymer  that is flexible and resistant to fracture. The aragonite gives relative rigidity to the material and the protein counteracts the brittleness of the aragonite by preventing the spread of fractures. The result is a natural product that is tough and resilient.  Mother of pearl has a hardness of about 3.5 on Moh’s scale. This is quite soft compared with gemstones and most metals. Mollusks create Mother of Pearl to protect themselves In addition to forming part of the shell, it also insulates mollusks from bacterial infection and parasites. Another function of this substance is to reduce irritation or damage from material such as sand or grit that drifts into the shell. The particle is gradually surrounded by layers of nacre, rendering it harmless. This may result in a blister-like irregularity on the inside of the shell, or it may create the unattached, spherical structure that is much prize

What is the name of the so-called 'first-bird'?

Archaeopteryx - CreationWiki, the encyclopedia of creation science Archaeopteryx Binomial Name Archaeopteryx lithographica Archaeopteryx is an extinct bird that evolutionists argue possesses some reptilian-like features causing it to be classified as a evolutionary transitional form , and is considered the first of the so called feathered dinosaurs . It has been associated, geologically with the late Jurassic and dated by radiometric dating methods at 150 million years. According to the U.S. National Park Service (Dinosaur National Monument): “ Fossils of Archaeopteryx, a little animal that lived in the middle of dinosaur times, do show traces of feathers, so it has often been called the first bird. But the skeleton of Archaeopteryx looks almost exactly like that of a small meat-eating dinosaur, right down to its tiny sharp teeth. So what was it- -a bird or a dinosaur? Some scientists think that Archaeopteryx was both: a warm-blooded, feathered dinosaur that became the ancestor of the birds. [1] ” 6 See Also Morphology Archaeopteryx was a fully flying and perching bird (though it has an unfused spine, no bill, a reptilian skull, adult teeth, no reptilian snout and bony tail, features seen in no modern bird). Jonathan Sarfati speaks to its bird morphology. “ Archaeopteryx had fully-formed flying feathers (including asymmetric vanes and ventral, reinforcing furrows as in modern flying birds), the classical elliptical wings of modern woodland birds, and a large wishbone for attachment of muscles responsible for the down stroke of the wings. Its brain was essentially that of a flying bird, with a large cerebellum and visual cortex. The fact that it had teeth is irrelevant to its alleged transitional status—a number of extinct birds had teeth, while many reptiles do not. Furthermore, like other birds, both its maxilla (upper jaw) and mandible (lower jaw) moved. In most vertebrates, including reptiles, only the mandible moves. Finally, Archaeopteryx skeletons had pneumatized vertebrae and pelvis. This indicates the presence of both a cervical and abdominal air sac, i.e., at least two of the five sacs present in modern birds. This in turn indicates that the unique avian lung design was already present in what most evolutionists claim is the earliest bird. [2] ” Avian features Feathers are present. No other modern animals except birds have feathers. Archaeopteryx had an opposable hallux (big toe). It is a character of birds and not dinosaurs. A reverse toe is however found in theropod dinosaurs and some other dinosaurs. Furcula (wishbone) formed of two clavicles fused together in the midline. Publis elongate and direct backwards. Bones are pneumatic. Premaxilla and maxilla are not horn-covered (or bills are not present). Trunk region and vertebrae are fused. But in other birds they are always fused. Necks are attached to skull from the rear as in dinosaurs, not from below as in modern birds. Archaeopteryx had a long bony tail. Archaeopteryx had teeth. Nasal opening are far forward and are separated from the eye by a large preorbital fenestra (hole). This is typical of reptiles, but not of birds. Fenestra when present in birds when present is greatly reduced, and is involved in prokinesis (movement of the beak). Recent discoveries seem to have shown that there are enough similarities between Archaeopteryx and Dromaeosaur that they can be considered varieties of the same created kind . This includes evidence from Dromaeosaur's feathers that it could fly. Archaeopteryx is dated as 20 million years older than Dromaeosaur. Archaeopteryx could not have evolved from Dromaeosaur. In fact Archaeopteryx is older than most of its alleged ancestors, which is a BIG problem for evolutionists, assuming total and complete replacement (thus extinction) of the original species . [Reference needed] News

What is the Latin word for 'liquid' which we use to mean the fluid produced by the tree Ficus elastica?

Tapping Trees for Natural Rubber - How Rubber Works | HowStuffWorks Tapping Trees for Natural Rubber Bryn Campbell/ Getty Images ­The Mesoamerican peoples, such as the Mayans and the Aztecs , first tapped rubber from one of several trees found in Central and South America: Hevea braziliensis: the most common commercial rubber tree from Brazil Hevea guyanensis: originally found in French Guyana Castilla elastica: sometimes called the Mexican rubber tree or the Panama rubber tree Explorers and colonists brought samples of these trees when they headed back to Europe . Eventually, seeds from these trees were transported to rubber plantations in other tropical climates during the era of European colonialism. Up Next Currently, most natural rubber comes from Latin American-derived trees transplanted to Southeast Asia ( Thailand , Indonesia , Malaysia ), as w­ell as India , Sri Lanka and Africa . In these areas, you can find other rubber-producing trees including: Ficus elastica: found in Java and Malaysia. This species is also a common tropical houseplant. Funtumia elastica: grows in West Africa Landolphia owariensis located in the Congo basin Of all of these trees, the best rubber-producing tree is H. braziliensis. It takes about six years for a rubber tree to grow to a point where it's economical to harvest the sap, which is called latex. Here's how you tap one: The collector makes a thin, diagonal cut to remove a sliver of bark. The milky-white latex fluid runs out of the bark, much as blood would run out of a small superficial wound on your skin. The fluid runs down the cut and is collected in a bucket. After about six hours, the fluid stops flowing. In that six-hour period, a tree can usually fill a gallon bucket. The tree can be tapped again with another fresh cut, usually the next day. The Mesoamericans would dry the collected rubber latex and make balls and other things, like shoes. They would dip their feet in the latex and allow it to dry. After several dips and dryings, they could peel a shoe from their feet. Next, they smoked their new rubber shoes to harden them. The Mesoamericans also waterproofed fabrics by coating them with latex and allowing it to dry. This process was used to make rubber items until around the 1800s. Columbus brought back rubber balls with him upon returning from his second voyage to the New World, and in the early 1700s, rubber samples and trees were brought back to Europe. At that time, rubber was still a novelty. Rubber made in the Mesoamerican way resembled a pencil eraser. It was soft and pliable. In 1770, the chemist Joseph Priestley was the first to use rubber to erase lead marks. He coined the word "rubber" because he could remove the lead marks by rubbing the material on them. While it was useful for waterproofing fabrics and making homemade shoes, rubber had its problems. You can see these problems for yourself with a simple rubber pencil eraser. Take that eraser and place it under intense heat for several minutes. What do you see? The eraser should get very soft and sticky. Next, do the opposite -- place the eraser on ice or in a freezer for several minutes. What do you see? The eraser should get hard and brittle. The same thing happened to early rubber. Imagine what it would be like to walk around in your rubber shoes on a hot or cold day back then. The shoes wouldn't wear well. Likewise, your rubberized clothing might stick to your chair while you were sitting, especially on a warm day. Keep reading to learn what makes rubber so intrinsically stretchy.

What is the main use of the tree Citrus bergamia?

Bergamot oil (Citrus bergamia) - information on the origin, source, extraction method, chemical composition, therapeutic properties and uses. Go to shopping cart at bottom of page This fresh smelling essential oil is a favorite in aromatherapy and is great for creating a more relaxed and happy feeling, relieving urinary tract infections, boosting the liver, spleen and stomach, while fighting oily skin, acne, psoriasis, eczema, as well as cold sores. Oil properties The scent of the oil is basically citrus, yet fruity and sweet, with a warm spicy floral quality and is reminiscent of neroli as well as lavender oil. The color ranges from green to greenish-yellow and the oil has a watery viscosity. Origin of bergamot oil This tree is native to South East Asia, but was introduced to Europe, and particularly Italy and is also found in the Ivory Coast, Morocco, Tunisia and Algeria. Bergamot oil is made from a tree that can grow up to four meters high, with star-shaped flowers and smooth leaves, bearing citrus fruit resembling a cross between an orange and a grapefruit, but in a pear-shape. The fruit ripens from green to yellow. The oil is one of the most widely used in the perfumery and toiletry industry and forms, together with neroli and lavender, the main ingredient for the classical 4711 Eau-de-cologne fragrance. It is used to flavor Earl Grey tea. The name is derived from the city Bergamo in Lombardy, Italy, where the oil was first sold. Summary When you are looking for an oil to help with depression, SAD (Seasonal Affected Disorder) or generally feeling just a bit off, lacking in self-confidence or feeling shy, then consider bergamot oil. It also has superb antiseptic qualities that are useful for skin complaints, such as acne, oily skin conditions, eczema and psoriasis and can also be used on cold sores, chicken pox and wounds. It has a powerful effect on stimulating the liver, stomach and spleen and has a superb antiseptic effect on urinary tract infections and inflammations such as cystitis. Burners and vaporizers In vapor therapy, bergamot oil can be used for depression, feeling fed-up, respiratory problems, colds and flu, PMS and SAD. Blended massage oil or in the bath It can be used in a blended massage oil, or diluted in a bath to assist with stress, tension, SAD, PMS, skin problems, compulsive eating, postnatal depression, colds and flu, anxiety, depression, feeling fed-up and anorexia nervosa. Blended in base cream As a constituent in a blended base cream bergamot oil can be used for wounds and cuts, psoriasis, oily skin, scabies, eczema, acne, cold sores as well as chicken pox. Bergamot blends well with Although essential oils blend well with one another, bergamot oil goes particularly well with other essential oils such as black pepper , clary sage , cypress , frankincense , geranium , jasmine , mandarin , nutmeg , orange , rosemary , sandalwood , vetiver and ylang-ylang .   US$ 14.50 for 10 ml ( worldwide postage included ) To shop, click on the "Add to shopping cart" button above, which will add the item to your cart, where we accept Visa, MasterCard, Amex and Diners credit cards. After you have selected an item, other items can also be added to the cart. All products are accessible from the product catalogue , or from the list below. When you are ready to finalize your order, click the "Go to checkout now" button where you will be able to change quantities, delete items, or return if you decide to continue shopping. Remember - no order is final until you decide and place the order. For more information on shopping cart security, please click here . To access our fax form click here . Handling, shipping and postage to any destination in the world INCLUDED (EXCEPT SOUTH AFRICA) - this is the total price - there are no hidden extras.

Which physician developed a type of remedy involving wild flowers?

Dr Bach's system of 38 flower remedies Contact us if you have a specific question and can't find an answer on the site. Guide to the remedies Each of the 38 remedies discovered by Dr Bach is directed at a particular characteristic or emotional state. To select the remedies you need, think about the sort of person you are and the way you are feeling. For more information on each remedy in this list click the relevant link. It might help to read some case studies first to see how they work. Agrimony - mental torture behind a cheerful face Aspen - fear of unknown things

The best longbows were constructed from which wood?

Bow woods Bow building for poor people and apartment dwellers Brought to you by: SAM HARPER Home | Update Archives | Other bow building sites | Thanks to all who helped me | Gallery | Youtube Channel Bow woods There are bow woods I've tried and bow woods I haven't tried. This is a list of bow woods (and grass in the case of bamboo) I've tried or heard a lot about. I'm only considering limb wood material, not handle wood material. Don't limit yourself, though. People are trying new things all the time. Red oak The great thing about red oak is that it's easy to find and it's cheap. It's ideal for somebody who is just starting out. Just about every Home Depot or Lowes I've been to has it. They sell it in the perfect size, too. It comes in a 72" long board they call a 1x2, which is actually 3/4 x 1-1/2. Red oak is very porous, and most of the pores are in the early growth rings, so it's important to find a piece with thick late growth rings or else it will seem brittle. Those boards will feel heavier. If you find a board with very straight grain, you don't necessarily need to back it, but it's a good idea to back any board bow. Bamboo The wonderful thing about bamboo is that you're guaranteed to have straight grain. Bamboo bows rarely fail if done right. Some people call bamboo nature's fiberglass. It's great bow material, and it's cheap. Bamboo comes in different forms�raw bamboo and bamboo flooring boards. If you get the flooring boards, be sure to get vertical grain. The horizontal grain will come apart. Bamboo flooring makes a great bow if backed with raw bamboo. All bamboo bows are my personal favourite. They're quieter than any other bow I've made, and there's just something about the way they feel when you draw them and shoot them that's hard to describe. There's a smoothness about them. The only bad thing I have to say about bamboo bows is that they take a lot of set. It's a good idea to put a lot of reflex in the bow at glue-up if you want to have any left after tillering. Vertical grain flooring boards can also be cut into laminations. People sometimes refer to it as "action boo." It's ideal in the core of a fiberglass bow, because it's light and strong. Raw bamboo is just a slice of a solid piece of bamboo with the nodes still intact. It makes a great backing to almost any kind of bow. Bamboo is very strong in tinsel strength, so it needs to be very thin to avoid overpowering the belly wood. Some woods that are good with raw bamboo backing include osage, yew, ipe, and bamboo, because they can withstand the compression forces. Hickory Hickory is popular for backing bows. Like bamboo, it's very strong in tinsel strength, so it needs to be thin. It's not quite as strong in compression strength. It makes a good self bow, too. I haven't made a self bow out of it, but from what I've read, it's almost impossible to break. Some people question its durability, though. Apparently, it takes a lot of set over time and becomes sluggish. I think this may be due to the fact that hickory sucks up a lot of moisture from the atmosphere. It needs to be a tad dryer than other woods to get the best performance out of it. The only problem with using it to make a self bow is that it's almost impossible to get the bark off of it. I've heard several different methods, the most popular being to put it in a hot shower for 20 or 30 minutes before trying to get the bark off with a chisel. Osage Some people consider osage (bois d'ark) to be a weed, but to those of us who make bows, it's gold. I love everything about osage except for the fact that it's hard to find a straight piece of it without knots. It smells good, it looks good, and it's the ideal bow wood. It lasts forever without taking a set, and it's very strong in compression strength. I can't say enough about osage. I just love it. If only it were easier to come by! Ipe It's pronounced EE-pay. It's the same thing as Brazilian walnut. It's very strong, so you can make thinner and lighter limbs, resulting in a faster bow. It goes well with a bamboo backing. Ipe is used in decks, because

How many species of domestic dog are found today?

Domestic Dogs, Domestic Dog Pictures, Domestic Dog Facts - National Geographic Size relative to a 6-ft (2-m) man Please add a "relative" entry to your dictionary. Dogs were probably the first tame animals. They have accompanied humans for some 10,000 years. Some scientists assert that all dogs, domestic and wild, share a common ancestor in the small South Asian wolf. Today humans have bred hundreds of different domestic dog breeds—some of which could never survive in the wild. Despite their many shapes and sizes all domestic dogs, from Newfoundlands to pugs, are members of the same species—Canis familiaris. Although they have domestic temperaments, these dogs are related to wolves, foxes, and jackals. Domestic dogs still share many behaviors with their wild relatives. Both defend their territories and mark them by urinating on trees, rocks, fence posts, and other suitable sites. These scent posts serve notice to other dogs that an animal is occupying its territory. Many pet dogs also bury bones or favorite toys for future use, just as their wild relatives sometimes bury a kill to secure the meat for later feasts. Dogs communicate in several ways. Scent is one method, another is physical appearance. Body position, movement, and facial expression often convey a strong message. Many of these signals are recognizable even to humans, such as the excited tail-wagging of a happy dog or the bared teeth of an angry or threatened animal. Vocally, dogs communicate with a cacophony of sounds including barks, growls, and whines. Domestic dogs serve as more than companions; many earn their keep by working hard. Dogs herd livestock, aid hunters, guard homes, and perform police and rescue work. Some special animals even guide the blind—a poignant symbol of the dog's longstanding role as man's best friend.

What kind of creature is a barnacle?

Barnacle (Cirripedia) - Animals - A-Z Animals Characteristics unique to the animal Latch on to hard surfaces and shell made up from plates Barnacle Location Barnacle The barnacle is a hardy animal that is found in or very closely to sea water. Although it is frequently confused for a mollusc because of its hard outer shell, it is actually a crustacean, closely related to crabs and lobsters. Barnacles are most often seen as roughly circular sessile invertebrates (which means that they cannot move on their own), and are permanently attached to the substrate they live on. In their juvenile form they are free-floating, but eventually they attach themselves to any nearby rock, shell, or other object and stay there for the rest of their lives. Their shells are composed of calcite. Barnacles are often seen on crabs , whales, boats, rocks and on the shells of sea turtles . Although some species of barnacle are parasitic, most barnacle species are harmless, because they are filter feeders and do not interfere with an animal's normal diet and do not harm that animal that they live on in any way. Many species of barnacle are so harmless that in fact, an animal that is covered in them, may not even notice! There are more than 1,000 known species of barnacle that inhabit shallow and tidal waters around the world. Although many species of barnacle are very small, some can grow to as large as 7cm and even bigger barnacles can often be seen. Barnacles typically live for between 5 and 10 years, but some of the larger species are known to be much older. Barnacles attach themselves to animals when they are very young and in the larvae stage of their lives. Once the baby barnacle has effectively glued itself to something hard, a thin layer of flesh wraps around the barnacle and an outer shell is produced. Once the barnacle has an outer shell, it is protected from the elements and all kinds of predators . As soon as the baby barnacle has fixed itself onto something, it is generally there for the rest of it's life. Barnacles are filter feeders (also known as suspension feeders) that feed on food particles that they strain out of the water. The shell of the barnacle is made up of a number of plates (usually 6), with feathery leg-like appendages that draw water into their shell so that they can feed. Barnacles have numerous predators , particularly when they are babies and floating around in the water looking for something to attach themselves to. As the barnacle larvae are so tiny, they float around with the plankton in the water. Once the barnacle is older and has it's tough outer shell, few predators can actually eat it. Humans are known to eat goose barnacles (the only edible species of barnacle) in parts of Europe like Spain and Portugal. Most species of barnacles are hermaphroditic which means that they have both male and female reproductive organs . Although it is possible for barnacles to self-fertilise their eggs, it seems to be very rare so the eggs produced by one barnacle are usually fertilised by another barnacle . It takes more than 6 months for the barnacle larvae to start developing into the hardier adult barnacles. Barnacles are thought to be one of the oldest surviving creatures on the planet as they are believed to date back millions of years. Although there will have been some adaptations, the barnacle is thought to have changed very little over that time. Despite the rising levels of pollution and changes in the water, barnacles are thought to be one of the few animals that are not greatly affected. The barnacle slides two of it's six plates across to let water in when it is feeding and then closes them again which prevents the barnacle from being too exposed to dirty water. Share This Article

Machiavelli used which plant's name as the title of one of his books?

Machiavelli, Comedian | The Public Domain Review ..or BROWSE BY TAG Machiavelli, Comedian Most familiar today as the godfather of Realpolitik and as the eponym for all things cunning and devious, the Renaissance thinker Niccolò Machiavelli also had a lighter side, writing as he did a number of comedies. Christopher S. Celenza looks at perhaps the best known of these plays, Mandragola, and explores what it can teach us about the man and his world. Illustration of Machiavelli featured in the title page to Historie di Nicolo Machiavegli cittadino & secretario fiorentino (1540) – Source . “Comedian”, admittedly, isn’t the first word you associate with Machiavelli. And “funny” is not a word normally applied to Lucretius. And yet, through some strange alchemy of time, circumstance, and the rhythms of Renaissance life, those seemingly discordant elements came together in a remarkable way. You could argue that Machiavelli’s entire worldview was comic, but comic in a peculiar way: ironic, wry, a little melancholy, punctuated by an earthy vulgarity that, these days, would get him thrown off a university faculty in a minute. More than this, the central premises of what was funny have changed so significantly that it invites us to think about how comedy works and when it’s time to say that a comedy, however venerable, just isn’t funny anymore. Take his play, Mandragola, or, in English, “The Mandrake Root.” The odd title (and it would have been odd in Machiavelli’s day, too) has to do with fertility. The plant appears in the Bible, in contexts where carnal knowledge is in question, like when Leah, one of Jacob’s two wives, wants to convince him to lie with her (Gen. 30:14-16), or when, in the Song of Songs, a woman sings a song of her own seductiveness “I am my beloved’s, and his desire is toward me … The mandrakes give a smell, and at our gates are all manner of pleasant fruits ….” (Song of Songs, 7:10-13). If the lasting biblical associations of the plant had to do with love, the herb also had magical and spell-like connotations. It could be thought to induce a great and powerful sleep, and in some accounts was even thought to cry out when pulled from the earth. Image from Ibn Butlan’s 14th-century Tacuinum sanitatis in Medicina, portraying a favoured medieval method – using a dog and string – for safely extracting a mandrake without enduring its shrieks – Source . Machiavelli’s title enfolded many of these meanings. The play concerns a young man, Callimaco, who though Florentine in origin spent much of his youth in France. From clues in the play we learn he is about thirty years old and that the action is set in the year 1504. At a gathering of friends, all male of course, a debate breaks out over who has the more beautiful women, France or Italy. Though the debaters give the palm to French women, one of his Florentine friends says he has a relative, Lucrezia, whose beauty is unequalled anywhere. Callimaco becomes curious to the point of leaving France and going to Florence. There his curiosity escalates to passion, as he is all but driven mad by love after finally laying eyes on Lucrezia. As it happens Lucrezia is married to a slow-witted lawyer named Messer Nicia. They have been trying unsuccessfully to have children. Ligurio – a matchmaker and, not coincidentally, a friend of Callimaco – suggests that the couple’s troubles may allow Callimaco to get close to Lucrezia. At first, Ligurio suggests that the couple go to the baths, known to improve fertility. Callimaco says he will go, so that he can see Lucrezia and because di cosa nasce cosa – “one thing begets another”. He is ready to trust his instincts and improvise as need be to find a way to be with Lucrezia. But then another plan is hatched. This one involves an elaborate scheme whereby Callimaco, posing as a doctor, convinces dull-witted Nicia to have Lucrezia take a special potion to help her conceive. The catch? The first person to make love with Lucrezia after she takes this potion will die. But thereafter, she will be fertile, children will follow, and all will be well,

What is the name of the evolutionary theory suggesting that evolution has an uneven pace?

Modern Theory of Evolution For those that love God's creation Modern Theory of Evolution There is a modern theory of evolution. There are some things we have learned over the last 150 years since Charles Darwin first proposed his theory of "descent with modification." Darwin's theory was amazingly accurate considering the state of scientific knowledge in 1859. Darwin knew nothing of DNA or genes, backbones of the modern theory of evolution. He even leaned toward Lamarckism, the belief that traits developed during our lifetime would pass on to our children. Nonetheless, The basics of Darwin's theory of evolution were exactly right and have passed every test with flying colors for 150 years: My pages are prone to being a little long. I can't do you good service and make this page shorter. A fast reader can read this page in under 3 minutes. If you want to skim it, I have highlighted portions that will allow you to get the gist of the page. Nature's imperfect reproductive methods regularly produce mutations, so that there are always unique individuals. Individuals which, as a result of those mutations, are better adapted to their environment will have more offspring, either because they survive more often or are better able to attract mates. Those more suitable adaptations will be prone to spreading through an entire population. Over time, as those adaptations accumulate, populations are modified into new species. Given the immense amount of geologic time on this earth, this process, known as "natural selection," has produced all life on the earth from one or a few parents. This basic idea of descent with modification has been backed up on every front. Here, however, are some of the new things that we've learned over the last 150 years. DNA: The Book of Life The modern theory of evolution is able to speak much more clearly about how evolution happens due to the discovery of DNA, the genetic code that controls all natural life. Charles Darwin was able to say: Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first breathed. (On the Origin of Species, ch. 14) Darwin had to base that on the following similarities between all living things: Common chemical composition Common germinal vesicle (this is a nucleus that is formed when a cell begins to split in two) Common cellular structure Common laws of growth and reproduction As an example of these commonalities, he cited a common reaction to poisons, so that a gall-fly's secretions creates the same growth on a wild rose as it does on an oak tree (ibid.). From the modern theory of evolution we know that the similarities are far more than he could have imagined. Every living cell has a common code, the simple 4-letter code of DNA, that controls its growth and reproduction. Every human, every insect, every plant, and every bacteria consists of cells made of proteins that are coded for by DNA. All DNA is transferable. Some viruses, which are not even cells but mere snippets of DNA, have even been assimilated into human DNA during our evolutionary history (see Wikipedia, "Human Endogenous Retrovirus" ). Even more interestingly, today insulin for diabetics is produced by taking human DNA and putting it in bacteria or yeast cells so that they produce the exact insulin that our bodies produce. Here's how the International Diabetes Foundation describes it: Rather than being extracted from human pancreases, commercially available human insulin is manufactured through recombinant DNA technology, in which the gene for making human insulin is transferred into simple cells such as bacteria or bakerís yeast. The insulin made by those cells is identical to insulin made by the human pancreas. (From www.idf.org ) Whether you object to evolution or not, you have to admit that this method of insulin production is amazing. The modern theory of evolution takes into account the genetic code, which Darwin could have known nothing about. Punctuated Equilibrium We'll cover punctu

Which step in photosynthesis is responsible for splitting water molecules?

Chemistry for Biologists: Photosynthesis Leaves and leaf structure | The structure of the chloroplast and photosynthetic membranes | Stages of photosynthesis | Non-cyclic phosphorylation (the Z scheme) | Chemiosmosis and ATP synthesis | Cyclic phosphorylation | The light-independent reactions | Summary of stages of photosynthesis | Factors affecting the rate of photosynthesis | Test your knowledge Photosynthesis Photosynthesis is the process by which plants, some bacteria and some protistans use the energy from sunlight to produce glucose from carbon dioxide and water. This glucose can be converted into pyruvate which releases adenosine triphosphate (ATP) by cellular respiration. Oxygen is also formed. Photosynthesis may be summarised by the word equation: carbon dioxide + water glucose + oxygen The conversion of usable sunlight energy into chemical energy is associated with the action of the green pigment chlorophyll. Chlorophyll is a complex molecule. Several modifications of chlorophyll occur among plants and other photosynthetic organisms. All photosynthetic organisms have chlorophyll a. Accessory pigments absorb energy that chlorophyll a does not absorb. Accessory pigments include chlorophyll b (also c, d, and e in algae and protistans), xanthophylls, and carotenoids (such as beta-carotene). Chlorophyll a absorbs its energy from the violet-blue and reddish orange-red wavelengths, and little from the intermediate (green-yellow-orange) wavelengths. Chlorophyll - click on image to open All chlorophylls have: a lipid-soluble hydrocarbon tail (C20H39 -) a flat hydrophilic head with a magnesium ion at its centre; different chlorophylls have different side-groups on the head The tail and head are linked by an ester bond. Leaves and leaf structure Plants are the only photosynthetic organisms to have leaves (and not all plants have leaves). A leaf may be viewed as a solar collector crammed full of photosynthetic cells. The raw materials of photosynthesis, water and carbon dioxide, enter the cells of the leaf, and the products of photosynthesis, sugar and oxygen, leave the leaf. Water enters the root and is transported up to the leaves through specialized plant cells known as xylem vessels. Land plants must guard against drying out and so have evolved specialized structures known as stomata to allow gas to enter and leave the leaf. Carbon dioxide cannot pass through the protective waxy layer covering the leaf (cuticle), but it can enter the leaf through the stoma (the singular of stomata), flanked by two guard cells. Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata. Unfortunately for the plant, while these gases are moving between the inside and outside of the leaf, a great deal of water is also lost. Cottonwood trees, for example, will lose 100 gallons (about 450 dm3) of water per hour during hot desert days. The structure of the chloroplast and photosynthetic membranes The thylakoid is the structural unit of photosynthesis. Both photosynthetic prokaryotes and eukaryotes have these flattened sacs/vesicles containing photosynthetic chemicals. Only eukaryotes have chloroplasts with a surrounding membrane. Thylakoids are stacked like pancakes in stacks known collectively as grana. The areas between grana are referred to as stroma. While the mitochondrion has two membrane systems, the chloroplast has three, forming three compartments. Structure of a chloroplast Stages of photosynthesis When chlorophyll a absorbs light energy, an electron gains energy and is 'excited'. The excited electron is transferred to another molecule (called a primary electron acceptor). The chlorophyll molecule is oxidized (loss of electron) and has a positive charge. Photoactivation of chlorophyll a results in the splitting of water

Which kind of organisms are likely to show a 'taxis'?

HOW AND WHY WE CLASSIFY LIVING ORGANISMS Content Updated: 20th July 2008 Generally-speaking, we humans have a desire to label and categorize things – hands up those who keep their t-shirts in a separate drawer to their underwear and/or arrange them in order of most recently worn or colour. Coupled with our desire for order (some teenagers excluded!), is an equally strong desire to name things we’ve sorted. The great Chinese thinker and philosopher K'ung Fu Tzu (better known by his Latin name: Confucius) is widely credited as being the source of the old Chinese proverb: “The beginning of wisdom is to call things by their right name.” But, what’s the point of naming things? Why go to the hassle of trying to give every novel object its own name? We name objects because it makes our life easier. Let’s say you’re sitting on the sofa and you want your friend to pass the remote so you can see what else is on the TV – this process is rather difficult without names. A request like, “Please pass the thing on the thingy. I want to see what’s on the whats-am-a-jig”, is likely to meet with confusion. The request is easier for the other person to follow if things have names: “Please pass the remote on the coffee table. I want to see what’s on the TV”. Now, it’s true that you might be able to gesticulate at your friend until he or she either gets the idea, or misinterprets and takes offence, but what if you can’t see the person you need help from – charades doesn’t help then. Imagine that you’re sitting on the train going to work when you remember you forgot to get the pie out of the freezer to defrost in time for dinner; fortunately your partner has the day off and is at home. So, you phone up and ask “Can you get the thing out of the thingy so it’s thingy-ed in time for what’s-its-name?” Again, confusion reigns. Gesticulating won’t help because the other person can’t see you (although it might make a dull train ride more interesting for your fellow passengers!). The instructions can be followed when we insert the names: “Can you get the pie out of the freezer so that it’s defrosted in time for dinner?” So, the act of naming is a matter of convenience – whether the objects are pieces or furniture, bits of machinery, or animals we assign them names because it makes life a heck of a lot easier for us. We, for example, call a ‘fish’ with a cartilaginous skeleton and between five and seven pairs of gills a “shark”. This allows us to tell another person what animal we’re looking at or talking about. The use of a name certainly helps, but not without problems. Telling someone that you went diving with sharks while on holiday is kinda like saying you went out for dinner with some primates; it’s not quite as specific as we might want because there are lots of different ‘types’ of primates (and sharks). Consequently, to make our meaning as clear as possible, objects (be they animals, plants, bacteria, furniture, tools, etc.) are split into as narrow groups as possible and each group is given a name. So, for example, the group of ‘fish’ we call sharks gets further split up into different types of sharks based largely on how they look (their “morphology”), both internally (i.e. their skeleton, internal organs etc.) and externally (i.e. fins, gills, skin, colour etc.). Large groups are then split into smaller (i.e. more specific) ones and so on down the line until you have a group containing all the animals considered to be exactly the same in terms of the features we’re looking at (these can be morphological, genetic, ecological, biochemical, even behavioural): this is the species level (we’ll look at this in more detail later). Humans, chimpanzees, great white sharks, blackbirds, palmate newts and red squirrels are all examples of species. Some taxonomists opt to take the splitting below the species level and group animals into subspecies, infraspecies and forms (among others). Perhaps the extr

Which part of the brain regulates physiological stability in the body?

Human Physiology/Homeostasis - Wikibooks, open books for an open world Human Physiology/Homeostasis This is the latest reviewed version , checked on 21 December 2016. (+)  Quality: minimal   Overview[ edit ] The human organism consists of trillions of cells all working together for the maintenance of the entire organism. While cells may perform very different functions, all the cells are quite similar in their metabolic requirements. Maintaining a constant internal environment with all that the cells need to survive (oxygen, glucose, mineral ions, waste removal, and so forth) is necessary for the well-being of individual cells and the well-being of the entire body. The varied processes by which the body regulates its internal environment are collectively referred to as homeostasis. What is Homeostasis?[ edit ] Homeostasis in a general sense refers to stability or balance in a system. It is the body's attempt to maintain a constant internal environment. Maintaining a stable internal environment requires constant monitoring and adjustments as conditions change. This adjusting of physiological systems within the body is called homeostatic regulation. Homeostatic regulation involves three parts or mechanisms: 1) the receptor, 2) the control center and 3) the effector. The receptor receives information that something in the environment is changing. The control center or integration center receives and processes information from the receptor. And lastly, the effector responds to the commands of the control center by either opposing or enhancing the stimulus. This is an ongoing process that continually works to restore and maintain homeostasis. For example, in regulating body temperature there are temperature receptors in the skin, which communicate information to the brain, which is the control center, and the effector is our blood vessels and sweat glands in our skin. Because the internal and external environments of the body are constantly changing and adjustments must be made continuously to stay at or near the set point, homeostasis can be thought of as a synthetic equilibrium. Since homeostasis is an attempt to maintain the internal conditions of an environment by limiting fluctuations, it must involve a series of negative feedback loops. Positive and Negative Feedback[ edit ] When a change of variable occurs, there are two main types of feedback to which the system reacts: Negative feedback: a reaction in which the system responds in such a way as to reverse the direction of change. Since this tends to keep things constant, it allows the maintenance of homeostasis. For instance, when the concentration of carbon dioxide in the human body increases, the lungs are signaled to increase their activity and expel more carbon dioxide. Thermoregulation is another example of negative feedback. When body temperature rises, receptors in the skin and the hypothalamus sense a change, triggering a command from the brain. This command, in turn, effects the correct response, in this case a decrease in body temperature. Home Heating System Vs. Negative Feedback When you are at home, you set your thermostat to a desired temperature. Let's say today you set it at 70 degrees. The thermometer in the thermostat waits to sense a temperature change either too high above or too far below the 70 degree set point. When this change happens the thermometer will send a message to to the "Control Center", or thermostat,which in turn will then send a message to the furnace to either shut off if the temperature is too high or kick back on if the temperature is too low. In the home-heating example the air temperature is the "NEGATIVE FEEDBACK." When the Control Center receives negative feedback it triggers a chain reaction in order to maintain room temperature. Positive feedback: a response is to amplify the change in the variable. This has a destabilizing effect, so does not result in homeostasis. Positive feedback is less common in naturally occurring systems than negative feedback, but it has its applications. For example, in nerves, a threshold electr

Which organ is responsible for regulating the blood sugar level?

Insulin Regulation of Blood Sugar and Diabetes - The Important Roles of Insulin and Glucagon: Diabetes and Hypoglycemia Normal Regulation of Blood Glucose The Important Roles of Insulin and Glucagon: Diabetes and Hypoglycemia Written by James Norman MD, FACS, FACE The human body wants blood glucose (blood sugar) maintained in a very narrow range. Insulin and glucagon are the hormones which make this happen. Both insulin and glucagon are secreted from the pancreas, and thus are referred to as pancreatic endocrine hormones. The picture on the left shows the intimate relationship both insulin and glucagon have to each other. Note that the pancreas serves as the central player in this scheme.  It is the production of insulin and glucagon by the pancreas which ultimately determines if a patient has diabetes, hypoglycemia, or some other sugar problem. In this Article Insulin's Role in Blood Glucose Control Insulin Basics: How Insulin Helps Control Blood Glucose Levels Insulin and glucagon are hormones secreted by islet cells within the pancreas. They are both secreted in response to blood sugar levels, but in opposite fashion! Insulin is normally secreted by the beta cells (a type of islet cell) of the pancreas. The stimulus for insulin secretion is a HIGH blood glucose...it's as simple as that!  Although there is always a low level of insulin secreted by the pancreas, the amount secreted into the blood increases as the blood glucose rises. Similarly, as blood glucose falls, the amount of insulin secreted by the pancreatic islets goes down.  As can be seen in the picture, insulin has an effect on a number of cells, including muscle, red blood cells, and fat cells.  In response to insulin, these cells absorb glucose out of the blood, having the net effect of lowering the high blood glucose levels into the normal range. Glucagon is secreted by the alpha cells of the pancreatic islets in much the same manner as insulin...except in the opposite direction. If blood glucose is high, then no glucagon is secreted.  When blood glucose goes LOW, however, (such as between meals, and during exercise) more and more glucagon is secreted. Like insulin, glucagon has an effect on many cells of the body, but most notably the liver. The Role of Glucagon in Blood Glucose Control The effect of glucagon is to make the liver release the glucose it has stored in its cells into the bloodstream, with the net effect of increasing blood glucose. Glucagon also induces the liver (and some other cells such as muscle) to make glucose out of building blocks obtained from other nutrients found in the body (eg, protein). Our bodies desire blood glucose to be maintained between 70 mg/dl and 110 mg/dl (mg/dl means milligrams of glucose in 100 milliliters of blood). Below 70 is termed "hypoglycemia." Above 110 can be normal if you have eaten within 2 to 3 hours.  That is why your doctor wants to measure your blood glucose while you are fasting...it should be between 70 and 110.  Even after you have eaten, however, your glucose should be below 180. Above 180 is termed "hyperglycemia" (which translates to mean "too much glucose in the blood"). If your 2 two blood sugar measurements above 200 after drinking a sugar-water drink (glucose tolerance test), then you are diagnosed with diabetes.   Updated on: 03/02/16

What is the scientific name for the human ''tail'?

The science of human tails The science of human tails Go to permalink Some hold with the theory that the development of an embryo shows the stages of evolution. In other words, what first develops is fishlike, and then like a small mammal, and then like a lemur or ape, and then something we would recognize as human. Very early embryos have what look like little gill slits in the beginning of their development. At about four weeks, embryos have a little tail. At around six to twelve weeks, the white blood cells dissolve the tail, and the fetus develops into an average, tail-less baby... most of the time, at least. Every now and again, we get a little extra bit of baby, in the form of a vestigial tail. Advertisement Not all things that look like tails - protrusions from the tailbone - actually are what doctors consider "true" tails. There are a number of growths or cysts that can form right on the tip of the tailbone. Some of the more unpleasant options are large tumors, elongation of the existing vertebrae, and even parasitic twin tissue. (A parasitic twin is not a fully-formed twin, but the product of another fertilized egg that somehow became fused with the embryo and never developed into a full human being.) True tails form when the white blood cells, for whatever reason, don't absorb all the tissue that formed during embryonic development. These babies carry the marks of humans earliest ancestors. Because there are only between 20 and 30 cases of "true" vestigial tails since the late 1800s, there is some controversy about what such a tail contains. Some early accounts say that there are sometimes extra vertebrae in such tails. No modern tails have been found to have any bone tissue. They're mostly skin with fat, connective tissue, nerves, and muscle tissue. They can be just a stub, but some babies can be born with tails 13 centimeters long. The tails aren't strictly useless inert structures. Because they have muscle tissue inside, they can actually be twitched back and forth, or even contracted into curves. These days babies don't have their tails long enough to gain a lot of muscle control over them. Removing them is a simple operation, usually done not long after birth. Advertisement What remains are questions of why these tails grow in the first place. They're rare enough that researchers aren't left with many clues. Researchers have, for the most part, ruled out family history - which throws the science of the X-Files episode I got the top image from right out the window. The tails are associated with spina bifida, a dangerous condition in which the canals of the spinal cord don't entire close before birth, but they are often present without the disorder. And for some reason they're twice in common in males as they are in females. In the end, no one knows why some babies just develop tails. (Besides, gills are much more practical.)

When might a person show rapid eye movement (REM)?

Understanding Dreams and REM Sleep Understanding Dreams and REM Sleep Search the site Updated August 02, 2016 What are Dreams? Dreams happen during the rapid eye movement (REM) stage of sleep . In a typical night, you dream for a total of 2 hours, broken up by the sleep cycle . Researchers do not know much about how we dream or why. They do know that newborns dream and that depriving rats of REM sleep greatly shortens their lives. Other mammals and birds also have REM sleep stages, but cold-blooded animals such as turtles, lizards and fish do not. REM Sleep and Dreaming REM sleep usually begins after a period of deep sleep known as stage 4 sleep. An area of the brain called the pons--where REM sleep signals originate--shuts off signals to the spinal cord . That causes the body to be immobile during REM sleep. When the pons doesn't shut down the spinal cord's signals, people will act out their dreams. This can be dangerous because acting out dreams without input from the senses can lead a person to run into walls, fall down stairs or worse. This condition is rare and different from more common sleepwalking and known as “REM sleep behavior disorder.” The pons also sends signals to cerebral cortex by way of the thalamus (which is a filter and relay for sensory information and motor control functions deep in the brain). The cerebral cortex is the part of the brain involved with processing information (learning, thinking and organizing). The areas of the brain “turned on” during REM sleep seem to help learning and memory. Infants spend almost 50 percent of their sleep time in REM sleep (compared to 20 percent for adults), which may be explained by the tremendous amount of learning in infancy. If people are taught various skills and then deprived of REM sleep, they often cannot remember what they were taught. The Meaning of Dreams Dreams may be one way that the brain consolidates memories. The dream time could be a period when the brain can reorganize and review the day’s events and connect new experiences to older ones. Because the body is shut down, the brain can do this without additional input coming in or risking the body “acting out” the day’s memories. Some researchers believe that dreams are more like a background “noise” that is interpreted and organized. This theory states that dreams are merely the brain’s attempt to make sense of random signals occurring during sleep. Some people have more control over their dreams than others. For these people, the last thoughts before going to bed may influence the content of a dream. Of course, psychologists and most people look for greater meaning and insight in dreams. Here are some common dreams with interpretations: Falling: Dreams of falling are said to indicate insecurity. Freud thought dreams of falling meant the contemplation of giving into a sexual urge. Flying: Dreams of flying are said to indicate feeling in control or 'on top of' a situation. The Naked Dream: Dreams of being naked are said to indicate that you are ashamed of something or have something to hide. Personally, these interpretations feel a bit too pop psych to me. I think by engaging with your dreams and thinking about them you can determine what meaning might be conveyed for your life. (I keep having a dream about forgetting to wear socks, please leave comments if you have any insight). You can develop your ability to remember your dreams by keeping a journal near your bed and writing down everything you can about your dreams when you first wake up. After a few weeks, your ability to remember your dreams will improve. Some people claim that they have lucid dreams, which are dreams in which they can participate and change the dream as it develops. Lucid dreaming can be triggered through a number of techniques, though little research and lots of speculation has been done on it.

Which organ removes excess water from the blood?

Which organ removes excess water, salts, uric acids, and chemicals from the blood? the kidneys, the lungs, the sweat glands, or the pharynx ? You have new items in your feed. Click to view. Question and answer Which organ removes excess water, salts, uric acids, and chemicals from the blood? the kidneys, the lungs, the sweat glands, or the pharynx ? The organ that is responsible for all of these removals is the kidney Expert answered| Ashnicole49 |Points 70| Which organ removes excess water, salts, uric acids, and chemicals from the blood? the kidneys, the lungs, the sweat glands, or the pharynx ? New answers There are no new answers. Comments Log in or sign up first. Questions asked by the same visitor Weegy: The correct answer is decreases. (More) Question Asked 12/3/2012 8:20:08 PM 0 Answers/Comments Weegy: Distribution systems: allocate endless goods and services. (More) Question Asked 12/3/2012 8:22:56 PM 0 Answers/Comments Why is the majority of Earth's freshwater not readily available for our use? It is in the atmosphere. ? It is locked up in glaciers and ice caps. ? It is in rivers far from major human population centers. ? or It is in the ground. ? Weegy: The answer to your questions , The majority of Earth's freshwater not readily available for our use because out of all the water on Earth, only 2.75 percent is freshwater, which includes 2.05 percent frozen in glaciers. [ This leaves a very small amount of non salt water. Most is locked up in glaciers and icecaps in Greenland and Antarctica, in saline inland seas or in the atmosphere, and is not readily available for consumptive use. ] (More) Question Asked 12/3/2012 8:29:42 PM 0 Answers/Comments Weegy: Surface processes that work to break down rock are called weathering. (More) Question Asked 12/3/2012 8:58:25 PM 0 Answers/Comments On a global basis, which of the following is the largest reservoir of carbon? ANS: atmosphere. The important reservoirs are: Atmosphere: contains at present 750 GtC. In pre-industrial times it contained only about 570 GtC, this change corresponds to the variation in the abundance from 280 ppmv in pre-industrial times to 370 ppmv at present. Vegetation and soils in the land: these contain about 2200 GtC, in the form of all the mass of plants in the Earth and all the organic litter contained in the soil, which has a lot of carbon. surface ocean: contains 1000 GtC. Carbon dioxide is dissolved in the water. Most of the live organisms that carry out photosynthesis in the ocean are near the surface, they can absorb the dissolved carbon dioxide and release it when they die. The surface ocean can rapidly exchange carbon dioxide with the atmosphere. deep ocean: contains 39000 GtC. This contains much more carbon than all the reservoirs above, but it can only exchange carbon with the atmosphere very slowly. lithosphere and mantle: contains about one hundred million GtC. This is by far the largest reservoir. The carbon dioxide is stored in the interior of the Earth in the form of carbonate rocks, such as limestone, dolomites, and chalk. However, carbon from this reservoir is exchanged extremely slowly with the carbon in the ocean and atmosphere. Among this large reservoir there are also about 4000 GtC in the form of fossil fuels (oil, coal and natural gas). These fossil fuels have been buried for hundreds of millions of years and are now being extracted and burned by humans. Added 12/3/2012 9:28:23 PM

Which is the most acidic part of the digestive system?

Digestive System: Facts, Function & Diseases Digestive System: Facts, Function & Diseases By Kim Ann Zimmermann, Live Science Contributor | March 11, 2016 05:15pm ET MORE The human digestive system is a series of organs that converts food into essential nutrients that are absorbed into the body and eliminates unused waste material. It is essential to good health because if the digestive system shuts down, the body cannot be nourished or rid itself of waste. Description of the digestive system Also known as the gastrointestinal (GI) tract, the digestive system begins at the mouth, includes the esophagus, stomach, small intestine, large intestine (also known as the colon) and rectum, and ends at the anus. The entire system — from mouth to anus — is about 30 feet (9 meters) long, according to the  American Society of Gastrointestinal Endoscopy  (ASGE).  Digestion begins with the mouth. Even the smell of food can generate saliva, which is secreted by the salivary glands in the mouth, contains an enzyme, salivary amylase, which breaks down starch. Teeth, which are part of the skeletal system, play a key role in digestion. In carnivores, teeth are designed for killing and breaking down meat. Herbivores’ teeth are made for grinding plants and other food to ease them through the digestion process.  [ Image Gallery: The BioDigital Human ] Swallowing pushes chewed food into the esophagus, where it passes through the oropharynx and hypopharynx. At this point, food takes the form of a small round mass and digestion becomes involuntary. A series of muscular contractions, called peristalsis, transports food through the rest of the system. The esophagus empties into the stomach, according to the  National Institutes of Health  (NIH).  The stomach’s gastric juice, which is primarily a mix of hydrochloric acid and pepsin, starts breaking down proteins and killing potentially harmful bacteria, according to ASGE. After an hour or two of this process, a thick semi-liquid paste, called chyme, forms. At this point the pyloric sphincter valve opens and chyme enters the duodenum, where it mixes with digestive enzymes from the pancreas and acidic bile from the gall bladder, according to the  Cleveland Clinic . The next stop for the chyme is the small intestine, a 20-foot (6-meter) tube-shaped organ, where the majority of the absorption of nutrients occurs. The nutrients move into the bloodstream and are transported to the liver.  The liver creates glycogen from sugars and carbohydrates to give the body energy and converts dietary proteins into new proteins needed by the blood system. The liver also breaks down unwanted chemicals, such as alcohol, which is detoxified and passed from the body as waste, the Cleveland Clinic noted. Whatever material is left goes into the large intestine. The function of the large intestine, which is about 5 feet long (1.5 meters), is primarily for storage and fermentation of indigestible matter. Also called the colon, it has four parts: the ascending colon, the transverse colon, the descending colon and the sigmoid colon. This is where water from the chyme is absorbed back into the body and feces are formed primarily from water (75 percent), dietary fiber and other waste products, according to the Cleveland Clinic. Feces are stored here until they are eliminated from the body through defecation. Diseases of the digestive system Many symptoms can signal problems with the GI tract, including: abdominal pain, blood in the stool, bloating, constipation, diarrhea, heartburn, incontinence, nausea and vomiting and difficulty swallowing, according to the NIH. Among the most widely known diseases of the digestive system is  colon cancer . According to the Centers for Disease Control (CDC), 51,783 Americans died from colon cancer in 2011 (the most recent year for available data). Excluding skin cancers, colon and rectal cancer, or colorectal cancer, is the third most common cancer diagnosed in both men and women in the United States, according to the  American Cancer Society . Polyp growth and irregular cells, which may or ma

A deficiency of which vitamin can cause scurvy?

Scurvy: Causes, Symptoms and Treatments - Medical News Today Scurvy: Causes, Symptoms and Treatments Written by Peter Crosta M.A. 4 36 Scurvy is a disease caused by a diet that lacks vitamin C (ascorbic acid). Patients develop anemia , debility, exhaustion, edema (swelling) in some parts of the body, and sometimes ulceration of the gums and loss of teeth. The name scurvy comes from the Latin scorbutus. We have known about the disease in humans since ancient Greek and Egyptian times. Scurvy commonly is associated with sailors in the 16th to 18th centuries who navigated long voyages without enough vitamin C and frequently perished from the condition. Modern cases of scurvy are extremely rare. Humans cannot synthesize vitamin C, which is necessary for the production of collagen and iron absorption. We have to obtain it from external sources, i.e. from fruits and vegetables, or some foods which are fortified with vitamin C in order to prevent the vitamin C deficiency known as scurvy. Vitamin C deficiency is especially dangerous for the fetus (developing baby in the womb). Researchers from the University of Copenhagen reported in the journal PLOS ONE that pregnant women with a vitamin C deficiency can have babies whose brain did not develop properly . What causes scurvy? The primary cause of scurvy is insufficient intake of vitamin C (ascorbic acid). This may be due to ignorance, famine, anorexia , restrictive diets (due to allergies, food fads, etc.), or difficulty orally ingesting foods. Historically, scurvy was the result of long sea voyages where sailors did not bring along enough foods with vitamin C. Who gets scurvy? Though scurvy is a very rare disease, it still occurs in some patients - usually elderly people, alcoholics, or those that live on a diet devoid of fresh fruits and vegetables. Similarly, infants or children who are on special or poor diets for any number of economic or social reasons may be prone to scurvy. Symptoms of scurvy Scurvy symptoms may begin with appetite loss, poor weight gain, diarrhea , rapid breathing, fever , irritability, tenderness and discomfort in legs, swelling over long bones, bleeding (hemorrhaging), and feelings of paralysis. As the disease progresses, a scurvy victim may present bleeding of the gums, loosened teeth, petechial hemorrhage of the skin and mucous membranes (a tiny pinpoint red mark), bleeding in the eye, proptopsis of the eyeball (protruding eye), constochondral beading (beading of the cartilage between joints), hyperkeratosis (a skin disorder), corkscrew hair, and sicca syndrome (an automimmune disease affecting connective tissue). Infants with scurvy will become apprehensive, anxious, and progressively irritable. They often will assume the frog leg posture for comfort when struck with pseudoparalysis. It is common for infants with scurvy to present subperiosteal hemorrhage, a specific bleeding that occurs at the lower ends of the long bones. Diagnosis of scurvy Physicians initially will conduct a physical exam, looking for symptoms described above. Actual vitamin C levels can be obtained by using laboratory tests that analyze serum ascorbic acid levels (or white blood cell ascorbic acid concentration). Sometimes, radiological procedures are ordered for diagnostic purposes and to see what damage scurvy has already done. Treatments for scurvy Scurvy is treated by providing the patient with vitamin C, administered either orally or via injection. Orange juice usually functions as an effective dietary remedy, but specific vitamin supplements are also known to be effective. How can scurvy be prevented? Scurvy can be prevented by consuming enough vitamin C, either in the diet or as a supplement. Foods that contain vitamin C include: Oranges, lemons, kiwi fruit and strawberries are all excellent natural sources of vitamin C. Oranges