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Suppose that you have an abstract for a scientific paper: the recently proposed effective potential theory [ phys . rev . lett . 110 , 235001 ( 2013 ) ] allows evaluating transport in coupled plasmas with the well - developed formalisms for systems with binary collisions . to facilitate practical implementation of this concept in fluid models of multi - component plasmas , compact expressions for the transport coefficients in terms the generalized coulomb logarithms are summarized from existing prescriptions . for weakly coupled plasmas , characterized by debye - shielded coulomb interaction potential , expressions become fully analytical . in coupled plasmas the generalized coulomb logarithms need to be evaluated numerically . routines implementing the described formalisms are included as supplemental material . . And you have already written the first three sentences of the full article: evaluation of the transport coefficients for coupled plasmas is greatly complicated by the many - body physics of particle collisions . the recently proposed effective potential theory ( ept ) addresses this issue by stipulating that , as far as transport is concerned , collisions can be considered effectively binary even at finite coupling , with the many - body physics manifesting itself solely through modifying the interaction potential between the two colliding particles @xcite . in turn , the effective potential enters expressions for the transport coefficients through the so - called generalized coulomb logarithms " , which are closely related to the standard gas - kinetic cross sections . the resulting transport predictions for a one component plasma ( ocp ) prove in a remarkable agreement with molecular dynamics ( md ) simulations , encouraging extension of the ept concept to the case of a plasma with multiple ion species .. Please generate the next two sentences of the article

while kinetic calculations for multi - component systems are more complex , the problem is well explored in the literature on diluted gas mixtures . in this note we summarize the existing transport results in the form convenient for practical use . local transport formalisms for systems with binary collisions assume that the distribution function @xmath0 of a given species @xmath1 weakly deviates from equilibrium , @xmath2 , due to the knudsen number @xmath3 being small , where @xmath4 and @xmath5 are the characteristic mean free path and background scale , respectively .

Suppose that you have an abstract for a scientific paper: an energy - minimal simulation is proposed to study the patterns and mechanical properties of elastically crumpled wires in two dimensions . we varied the bending rigidity and stretching modulus to measure the energy allocation , size - mass exponent , and the stiffness exponent . the mass exponent is shown to be universal at value @xmath0 . we also found that the stiffness exponent @xmath1 is universal , but varies with the plasticity parameters @xmath2 and @xmath3 . these numerical findings agree excellently with the experimental results . . And you have already written the first three sentences of the full article: the process of crumpling is everywhere in nature and human activities , including the formation of mountains and valleys in tectonics@xcite , packing of dna strands in viruses@xcite , car wreckage after an accident@xcite , or the noisy food wraps that drive us nut in the theater , etc .. in spite of its ubiquity , the mechanism behind many of its properties has remained unclear@xcite . for instance , how does the labyrinthian internal structure evolve such that it can withstand extraordinary pressure while more than 80% of its interior remains vacant ? also , why is it that there exists a power law between the external force and the sphere radius with an exponent that varies with material@xcite but , otherwise , is insensitive to the thickness and size of the thin sheet ?. Please generate the next two sentences of the article

scientists have studied crumpled wires ( cw ) both theoretically@xcite and experimentally@xcite . as is shown in fig.[fig : photo ] , the wire is smooth and rid of the complicated ridges and vertices , which is different from a crumpled sheet@xcite . in the last few years , more and more interesting properties of cw have emerged . for instance , donato _

Suppose that you have an abstract for a scientific paper: we discuss the effect of disorder on the coherent propagation of the bound state of two attracting particles . it is shown that a result analogous to the anderson theorem for dirty superconductors is also valid for the cooper problem , namely , that the pair wave function is extended beyond the single - particle localization length if the latter is large . a physical justification is given in terms of the thouless block - scaling picture of localization . these arguments are supplemented by numerical simulations . with increasing disorder we find a transition from a regime in which the interaction delocalizes the pair to a regime in which the interaction enhances localization . . And you have already written the first three sentences of the full article: it has long been known that the wave function of an electron moving in a random potential becomes spatially localized . this effect was first predicted by anderson @xcite and is termed _ anderson localization_. in one and two dimensions _ all _ quantum states are localized in the presence of _ any _ amount of disorder while in three dimensions localization occurs only above some critical disorder . while this phenomenon is now fairly well understood in a single - particle picture ,. Please generate the next two sentences of the article

the inclusion of interactions in the disordered many - body system is a non - trivial problem . insight can be gained by studying the simpler case of just two interacting particles in a random potential . in this context , it has recently been claimed that the interaction can actually lead to a _ delocalization _ effect , in the sense that the spatial extent of the two - body wave function is larger than the single - particle localization length @xcite .

Suppose that you have an abstract for a scientific paper: a microscopic few - body description of near - threshold coherent photoproduction of the @xmath0 meson on tritium and @xmath1he targets is given . the photoproduction cross - section is calculated using the finite rank approximation ( fra ) of the nuclear hamiltonian . the results indicate a strong final state interaction of the @xmath0 meson with the residual nucleus . sensitivity of the results to the choice of the @xmath2 @xmath3-matrix is investigated . pacs numbers : 25.80.-e , 21.45.+v , 25.10.+s . And you have already written the first three sentences of the full article: investigations of the @xmath0-nucleus interaction are motivated by various reasons . some of them , such as the possibility of forming quasi - bound states or resonances @xcite in the @xmath0-nucleus system , are purely of nuclear nature . the others are related to the study of the properties and structure of the @xmath4 resonance which is strongly coupled to the @xmath5 channel .. Please generate the next two sentences of the article

for example , it is interesting to investigate the behavior of the @xmath0-meson in nuclear media where , after colliding with the nucleons , it readily forms the @xmath6 resonance . the interaction of this resonance with the surrounding nucleons can be described in different ways @xcite , depending on whether the structure of this resonance is defined in terms of some quark configurations or by the coupling of meson - baryon channels , as suggested in ref .

Suppose that you have an abstract for a scientific paper: based on a lie symmetry analysis , we construct a closed form solution to the kinematic part of the ( partial differential ) cosserat equations describing the mechanical behavior of elastic rods . the solution depends on two arbitrary analytical vector functions and is analytical everywhere except a certain domain of the independent variables in which one of the arbitrary vector functions satisfies a simple explicitly given algebraic relation . as our main theoretical result , in addition to the construction of the solution , we proof its generality . based on this observation , a hybrid semi - analytical solver for highly viscous two - way coupled fluid - rod problems is developed which allows for the interactive high - fidelity simulations of flagellated microswimmers as a result of a substantial reduction of the numerical stiffness . rods , differential thomas decomposition , flagellated microswimmers , general analytical solution , kinematic equations , lie symmetry analysis , stokes flow , symbolic computation . . And you have already written the first three sentences of the full article: studying the dynamics of nearly one - dimensional structures has various scientific and industrial applications , for example in biophysics ( cf . @xcite and the references therein ) and visual computing ( cf . @xcite ) as well as in civil and mechanical engineering ( cf .. Please generate the next two sentences of the article

@xcite ) , microelectronics and robotics ( cf . @xcite ) . in this regard , an appropriate description of the dynamical behavior of flexible one - dimensional structures is provided by the so - called special cosserat theory of elastic rods ( cf .

Suppose that you have an abstract for a scientific paper: we study the free path length and the geometric free path length in the model of the periodic two - dimensional lorentz gas ( sinai billiard ) . we give a complete and rigorous proof for the existence of their distributions in the small - scatterer limit and explicitly compute them . as a corollary one gets a complete proof for the existence of the constant term @xmath0 in the asymptotic formula @xmath1 of the ks entropy of the billiard map in this model , as conjectured by p. dahlqvist . . And you have already written the first three sentences of the full article: a periodic two - dimensional lorentz gas ( sinai billiard ) is a billiard system on the two - dimensional torus with one or more circular regions ( scatterers ) removed . this model in classical mechanics was introduced by lorentz @xcite in 1905 to describe the dynamics of electrons in metals . the associated dynamical system is simple enough to allow a comprehensive study , yet complex enough to exhibit chaos . according to gutzwiller @xcite : `` the original billiard of sinai was designed to imitate , in the most simple - minded manner , a gas of hard spherical balls which bounce around inside a finite enclosure .. Please generate the next two sentences of the article

the formidable technical difficulties of this fundamental problem were boiled down to the shape of a square for the enclosure , and the collisions between the balls were reduced to a single point particle hitting a circular hard wall at the center of the enclosure . '' the model was intensively studied from the point of view of dynamical systems @xcite .

Suppose that you have an abstract for a scientific paper: we present the results of a 2-d , two fluid ( ions and neutrals ) simulation of the ambipolar filamentation process , in which a magnetized , weakly ionized plasma is stirred by turbulence in the ambipolar frequency range . the higher turbulent velocity of the neutrals in the most ionized regions gives rise to a non - linear force driving them out of these regions , so that the initial ionization inhomogeneities are strongly amplified . this effect , the ambipolar filamentation , causes the ions and the magnetic flux to condense and separate from the neutrals , resulting in a filamentary structure . # 1 # 1 0.5 cm . And you have already written the first three sentences of the full article: magnetic fields contribute to the dynamical behavior of ionized astrophysical fluids such as those in the upper solar and stellar atmospheres , the interstellar medium and star - forming regions . their influence is carried out by hydromagnetic waves which efficiently propagate perturbations , ensure a turbulent pressure or may even cause the development of instabilities ( @xcite ) . however , kulsrud & pearce ( @xcite ) showed that in the magnetized and weakly ionized interstellar medium hydromagnetic waves are heavily damped in a frequency range ( and thus scale ) associated with ambipolar diffusion . at low frequency the neutrals. Please generate the next two sentences of the article

are well coupled to the ions ( which are tied to the magnetic field lines ) and hydromagnetic waves propagate at the alfvn speed defined by the total inertia ( given by ions+neutrals ) . at high frequency neutrals and ions are totally decoupled , and alfvn waves involve only the ions , which define a larger alfvn velocity . in the intermediate range ( the ` ambipolar

Suppose that you have an abstract for a scientific paper: we present two - color modulation transfer spectroscopy as a tool for precision studies of atomic properties of excited states . the bi - colored technique addresses a narrow set of velocity groups of a thermal atomic vapour using a two - step transition to burn a hole " in the velocity distribution . the resulting spectrum presents sub - doppler linewidths , good signal to noise ratio and the trademark sidebands that work as an _ in situ _ ruler for the energy spacing between atomic resonances . the spectra obtained can be used for different applications such as measurements of energy splittings or stabilization of laser frequencies to excited atomic transitions . = 10000 . And you have already written the first three sentences of the full article: spectroscopic studies of hyperfine manifolds in alkalies , such as measurements of energy separations , have benefitted by the high precision of the experimental techniques available to interrogate atoms @xcite . their hydrogen - like structure makes interpretation of experimental results straightforward in terms of electromagnetic fields generated by the valence electron and nuclear moments . precise measurements in higher excited states accessible through two - step transitions@xcite have appeared in recent years .. Please generate the next two sentences of the article

this has renewed interest in improving calculations in other states where theoretical methods such as many - body perturbation theory ( mbpt ) ( see for example the recent book of w. r. johnson @xcite ) are yet to be tested against experimental results . precise measurements in excited states , beyond the first one , have several experimental complications .

Suppose that you have an abstract for a scientific paper: recent progress in obtaining high spatial resolution images of the solar corona in the extreme - ultraviolet ( euv ) with hinode , trace , sdo and recent hi - c missions and soft x - ray ( sxr ) bands opened a new avenue in understanding the solar coronal heating , the major goal of solar physics . the data from euv / sxr missions suggest that solar corona is a non - uniform environment structured into active regions ( ar ) represented by bundles magnetic loops heated to temperatures exceeding 5 mk . any viable coronal heating model should be capable of reproducing euv and sxr emission from coronal active regions well as dynamic activity . measurements of emission measures ( em ) for ars provide clues to time dependence of the heating mechanism : static versus impulsive . while static equilibrium coronal loop models are successful in reproducing sxr emission within an ar , they can not adequately predict the bright euv loops . meantime , impulsive heating is capable in reproducing both euv and sxr loop emission . the major goal of this paper is to construct realistic synthetic em images of specific solar corona active region , ar 11117 by using our 1d fully non - linear time - dependent single - fluid hydrodynamic code . we first construct a magnetic skeleton for the entire active region using the hmi / sdo magnetogram for ar 11117 and populate magnetic field lines with plasma . we then parametrically specify impulsive heating of individual strands ( flux tubes ) comprising coronal loops . next , we simulated the response of the entire active region ( with los projection effects ) to the heating function ( volumetric heating rate ) scaled with magnetic field and spatial scale parameters and find the best match between synthetic and actual ( reconstructed ) dems obtained by sdo . . And you have already written the first three sentences of the full article: all stars later than f5 possess convective zones that drive hot corona heated to 1 - 10 mk . for this standpoint , the sun has a moderately heated corona ( 1 - 3 mk ) extending from the transition zone to a few solar radii . the solar coronal heating is observed in the soft x - ray ( sxr ) and euv bands and plays a critical role in controlling the thermodynamics and chemistry of the earth s upper atmosphere ( meier 1991 ) .. Please generate the next two sentences of the article

the corona s variable radiative output is associated with flares and coronal mass ejections that affect space weather , and eventually , life on earth . variations in the radiation affect radio signal propagation and satellite drag thereby impacting communication , navigation , surveillance , and space debris collision avoidance .

Suppose that you have an abstract for a scientific paper: high resolution spectra of the active binary capella ( g8 iii + g1 iii ) covering the energy range 0.4 - 8.0 kev ( 1.5 - 30 ) show a large number of emission lines , demonstrating the performance of the hetgs . a preliminary application of plasma diagnostics provides information on coronal temperatures and densities . lines arising from different elements in a range of ionization states indicate that capella has plasma with a broad range of temperatures , from @xmath0 , generally consistent with recent results from observations with the extreme ultraviolet explorer ( euve ) and the advanced satellite for cosmology and astrophysics ( asca ) . the electron density is determined from he - like o vii lines , giving the value @xmath1 at @xmath2 ; he - like lines formed at higher temperatures give only upper limits to the electron density . the density and emission measure from o vii lines together indicate that the coronal loops are significantly smaller than the stellar radius . . And you have already written the first three sentences of the full article: the active binary capella ( @xmath3 aurigae , hd 34029 , hr 1708 ) was observed with the high energy transmission grating spectrometer ( hetgs ) on the chandra x - ray observatory ( cxo ) . we present a first analysis of the spectra with the goals of demonstrating the hetgs performance , and of applying plasma diagnostics to infer physical parameters of the capella corona . a complementary analysis of the corona of capella based on high resolution spectra obtained using the cxo low energy transmission grating spectrometer ( letgs ) has been presented by @xcite .. Please generate the next two sentences of the article

further analysis of diagnostic emission lines from these and other chandra grating data of capella are underway with the goal of obtaining refined temperature - dependent emission measures , abundances , and densities , leading to a self - consistent determination of the coronal structure . [ [ the - chandra - hetgs ] ] the chandra hetgs : + + + + + + + + + + + + + + + + + + the high energy transmission grating assembly @xcite consists of an array of periodic gold microstructures that can be interposed in the converging x - ray beam just behind the chandra high resolution mirror assembly .

Suppose that you have an abstract for a scientific paper: the focus of this paper is on the co - design of control and communication protocol for the control of multiple applications with unknown parameters using a distributed embedded system . the co - design consists of an adaptive switching controller and a hybrid communication architecture that switches between a time - triggered and event - triggered protocol . it is shown that the overall co - design leads to an overall switching adaptive system that has bounded solutions and ensures tracking in the presence of a class of disturbances . . And you have already written the first three sentences of the full article: embedded control systems are ubiquitous and can be found in several applications including aircraft , automobiles , process control , and buildings . an embedded control system is one in which the computer system is designed to perform dedicated functions with real - time computational constraints @xcite . typical features of such embedded control systems are the control of multiple applications , the use of shared networks used by different components of the systems to communicate with each other for control , a large number of sensors as well as actuators , and their distributed presence in the overall system. Please generate the next two sentences of the article

. the most common feature of such distributed embedded control systems ( des ) is shared resources . constrained by space , speed , and cost , often information has to be transmitted using a shared communication network . in order to manage the flow of information in the network , protocols that are time - triggered @xcite and event - triggered @xcite

Suppose that you have an abstract for a scientific paper: we demonstrate that the non - relativistic fermions open the energy gap when the su(n ) gauge bosons , mediating the interaction between fermions , acquire the mass . surprisingly , even though there is the su(n ) gauge symmetry , there is always one fermionic energy gap which is not degenerate to the rest of the @xmath0 fermions for @xmath1 in the fundamental representation . energy gap , non - abelian gauge systems , strongly - correlated electrons . And you have already written the first three sentences of the full article: the energy gap formation is an ubiquitous phenomena in condensed matter systems . when the band structure appears in the one - particle hamiltonian with a periodic potential , the band gap is the region in the spectrum where there is no density of states . on the other hand , the repulsion interaction generates the energy gap in the fractional quantum hall systems . generally speaking ,. Please generate the next two sentences of the article

systems with an energy gap are more stable against perturbations . the systems with the energy gap are , however , not good nurturing cradles for the superconductivity , which arises in the systems with fermi surface ( gapless ) . because of the instability of the interaction with the phonons , the electrons pair up and condense to the superconducting state . however , there are some classes of superconductors which were obtained by doping the antiferromagnetic insulators with mobile carriers , for example high transition temperature superconductors in the cooper - based transition metal oxides ( cuprates ) @xcite . by the chemical doping ,

Suppose that you have an abstract for a scientific paper: the time dependence of the survival probability of an opinion in a closed community has been investigated in accordance with social temperature by using the kawasaki - exchange dynamics based on previous study in ref . [ 1 ] . it is shown that the survival probability of opinion decays with stretched exponential law consistent with previous static model . however , the crossover regime in the decay of the survival probability has been observed in this dynamic model unlike previous model . the decay characteristics of both two regimes obey to stretched exponential . * keywords : * ising model ; politics ; random walk ; sociophysics ; sznajd model . . And you have already written the first three sentences of the full article: binary models like ising - type simulation have a long history . they have been applied by schelling to describe the ghetto formation in the inner cities of the usa , i.e. , to study phase separation between black and white @xcite . in the sociophysics context , recently , many social phenomena such as election , propagation of information , predicting features of traffic , migration , opinion dynamics and formation in a social group have been successful modelled based on ising spin systems using models and tools of statistical physics . with this respect , particularly successful models have been developed by sznajd @xcite , deffuant et al.@xcite and hegselmann and krause @xcite . among those three models ,. Please generate the next two sentences of the article

the one developed by sznajd is the most appropriate for simulation in networks and lattices , since it consider just the interactions between the nearest neighbors . indeed , the sznajd model has been successfully applied to model sociophysical and economic systems @xcite . on the other hand , several modifications of the sznajd model

Suppose that you have an abstract for a scientific paper: as the title suggests , the purpose of this chapter is to review the current status of numerical simulations of black hole accretion disks . this chapter focuses exclusively on _ global _ simulations of the accretion process within a few tens of gravitational radii of the black hole . most of the simulations discussed are performed using general relativistic magnetohydrodynamic ( mhd ) schemes , although some mention is made of newtonian radiation mhd simulations and smoothed particle hydrodynamics . the goal is to convey some of the exciting work that has been going on in the past few years and provide some speculation on future directions . = 1 . And you have already written the first three sentences of the full article: going hand - in - glove with analytic models of accretion disks , discussed in chapter 2.1 , are direct numerical simulations . although analytic theories have been extremely successful at explaining many general observational properties of black hole accretion disks , numerical simulations have become an indispensable tool in advancing this field . they allow one to explore the full , non - linear evolution of accretion disks from a first - principles perspective .. Please generate the next two sentences of the article

because numerical simulations can be tuned to a variety of parameters , they serve as a sort of `` laboratory '' for astrophysics . the last decade has been an exciting time for black hole accretion disk simulations , as the fidelity has become sufficient to make genuine comparisons between them and real observations .

Suppose that you have an abstract for a scientific paper: we present a theoretical study of time - dependent quantum transport in a resonant tunnel junction coupled to a nanomechanical oscillator within the non - equilibrium green s function technique . an arbitrary voltage is applied to the tunnel junction and electrons in the leads are considered to be at zero temperature . the transient and the steady state behavior of the system is considered here in order to explore the quantum dynamics of the oscillator as a function of time . the properties of the phonon distribution of the nanomechnical oscillator strongly coupled to the electrons on the dot are investigated using a non - perturbative approach . we consider both the energy transferred from the electrons to the oscillator and the fano factor as a function of time . we discuss the quantum dynamics of the nanomechanical oscillator in terms of pure and mixed states . we have found a significant difference between a quantum and a classical oscillator . in particular , the energy of a classical oscillator will always be dissipated by the electrons whereas the quantum oscillator remains in an excited state . this will provide useful insight for the design of experiments aimed at studying the quantum behavior of an oscillator . . And you have already written the first three sentences of the full article: nanoscopic physics has been a subject of increasing experimental and theoretical interest for its potential applications in nanoelectromechanical systems ( nems)@xcite . the physical properties of these devices are of crucial importance in improving our understanding of the fundamental science in this area including many - body phenomena@xcite . one of the most striking paradigms exhibiting many body effects in mesoscopic science is quantum transport through single electronic levels in quantum dots and single molecules@xcite coupled to external leads . realizations of these systems have been obtained using semiconductor beams coupled to single electron transistors ( set s ) and superconducting single electron transistors ( ssets)@xcite , carbon nanotubes@xcite and , most recently , suspended graphene sheets@xcite . such systems can be used as a direct measure of small displacements , forces and mass in the quantum regime .. Please generate the next two sentences of the article

the quantum transport properties of these systems require extremely sensitive measurement that can be achieved by using set s , or a resonant tunnel junction , and sset s . in this context , nems are not only interesting devices studied for ultrasensitive transducers but also because they are expected to exhibit several exclusive features of transport phenomena such as avalanche - like transport and shuttling instability@xcite . the nanomechanical properties of a resonant tunnel junction coupled to an oscillator@xcite or a set@xcite coupled to an oscillator are currently playing a vital role in enhancing the understanding of nems .

Suppose that you have an abstract for a scientific paper: free induction decay ( fid ) measured by nuclear magnetic resonance ( nmr ) in a polycrystalline solid is the isotropic average of the fids for individual single crystallites . it has been recently proposed theoretically and verified experimentally that the long - time behavior of single - crystal fids has the universal form of exponentially decaying sinusoidal oscillations . polycrystalline averaging complicates the situation theoretically , while the available experimental evidence is also ambiguous . exponentially decaying sinusoidal oscillations have been observed for @xmath0xe in polycrystalline solid xenon but not for @xmath1f in the powder of caf@xmath2 . in this paper , we present the first principles fid calculations for the powders of both caf@xmath2 and solid xenon . in both cases , the asymptotic long - time behavior has the expected form of exponentially decaying sinusoidal oscillations , which is determined by the single crystallite fid with the slowest exponential decay . however , this behavior appears only at rather small values of the signal that have not yet been measured in experiments . at intermediate times accessible experimentally , a polycrystalline fid depends on the distribution of the exponential decay constants and oscillation frequencies for single crystallite fids . in caf@xmath2 , these parameters are relatively broadly distributed , and as a result , the sinusoidal long - time oscillations become somewhat washed out . in contrast , the single crystallite parameters are more clustered in solid xenon , and , as a result , the experimentally observable range is characterized by well - defined oscillation frequency and exponential decay constant even though both of these parameters do not represent the true long - time behavior . the above difference of the intermediate fid behavior originates from the difference of the crystal structures of solid xenon and caf@xmath2 . . And you have already written the first three sentences of the full article: first principles calculations of the free induction decay ( fid ) measured by nuclear magnetic resonance ( nmr ) in solids is a long - standing theoretical problem@xcite still lacking a controllable solution@xcite . the most challenging aspect of this problem is the prediction of the long - time behavior of the fids . recently some progress in this direction was made on the basis of the notion of microscopic chaos@xcite .. Please generate the next two sentences of the article

namely , it was predicted that the generic long - time behavior of fids in single crystals has the character of exponential decay with or without sinusoidal oscillations . in the most common case of magnetic dipolar interaction between nuclear spins , the oscillatory regime is realized , and hence , the long - time fid behavior can be parameterized as @xmath3 where @xmath4 , @xmath5 , @xmath6 and @xmath7 are some constants whose values were not predicted .

Suppose that you have an abstract for a scientific paper: the m82 ` cap ' is a gas cloud at a projected radius of 11.6 kpc along the minor axis of this well known superwind source . the cap has been detected in optical line emission and x - ray emission and therefore provides an important probe of the wind energetics . in order to investigate the ionization source of the cap , we observed it with the kyoto3dii fabry - perot instrument mounted on the subaru telescope . deep continuum , h@xmath0 , [ ] @xmath16583/h@xmath0 , and [ ] @xmath26716,6731/h@xmath0 maps were obtained with sub - arcsecond resolution . the superior spatial resolution compared to earlier studies reveals a number of bright h@xmath0 emitting clouds within the cap . the emission line widths ( @xmath3 km s@xmath4 fwhm ) and line ratios in the newly identified knots are most reasonably explained by slow to moderate shocks velocities ( @xmath5 = 4080 km s@xmath4 ) driven by a fast wind into dense clouds . the momentum input from the m82 nuclear starburst region is enough to produce the observed shock . consequently , earlier claims of photoionization by the central starburst are ruled out because they can not explain the observed fluxes of the densest knots unless the uv escape fraction is very high ( @xmath6 60% ) , i.e. , an order of magnitude higher than observed in dwarf galaxies to date . using these results , we discuss the evolutionary history of the m82 superwind . future uv / x - ray surveys are expected to confirm that the temperature of the gas is consistent with our moderate shock model . . And you have already written the first three sentences of the full article: superwinds are galaxy scale outflows , caused by supernovae in nuclear starburst regions or active galactic nuclei ( agns ) . they are so powerful that interstellar matter within the galaxies is blown out . some of the material may escape to the intergalactic or group medium , while some of the material may be recycled throughout the galactic halo @xcite .. Please generate the next two sentences of the article

superwinds are expected to quench star - formation activity ( feedback ) and to enrich the external medium with new metals . generally , galactic winds are diffuse and difficult to observe .

Suppose that you have an abstract for a scientific paper: we substantially update the capabilities of the open source software package modules for experiments in stellar astrophysics ( ` mesa ` ) , and its one - dimensional stellar evolution module , ` mesa ` ` star ` . improvements in ` mesa ` ` star ` s ability to model the evolution of giant planets now extends its applicability down to masses as low as one - tenth that of jupiter . the dramatic improvement in asteroseismology enabled by the space - based _ kepler _ and _ corot _ missions motivates our full coupling of the adipls adiabatic pulsation code with ` mesa ` ` star ` . this also motivates a numerical recasting of the ledoux criterion that is more easily implemented when many nuclei are present at non - negligible abundances . this impacts the way in which ` mesa ` ` star ` calculates semi - convective and thermohaline mixing . we exhibit the evolution of @xmath0 stars through the end of core he burning , the onset of he thermal pulses , and arrival on the white dwarf cooling sequence . we implement diffusion of angular momentum and chemical abundances that enable calculations of rotating - star models , which we compare thoroughly with earlier work . we introduce a new treatment of radiation - dominated envelopes that allows the uninterrupted evolution of massive stars to core collapse . this enables the generation of new sets of supernovae , long gamma - ray burst , and pair - instability progenitor models . we substantially modify the way in which ` mesa ` ` star ` solves the fully coupled stellar structure and composition equations , and we show how this has improved the scaling of ` mesa ` s calculational speed on multi - core processors . updates to the modules for equation of state , opacity , nuclear reaction rates , and atmospheric boundary conditions are also provided . we describe the mesa software development kit ( ` sdk ` ) that packages all the required components needed to form a unified , maintained , and well - validated build environment for ` mesa ` . we.... And you have already written the first three sentences of the full article: as the most commonly observed objects , stars remain at the forefront of astrophysical research . advances in optical detector technology , computer processing power , and data storage capability have enabled new sky surveys ( e.g. , the sloan digital sky survey ; * ? ? ? * ) ; triggered many new optical transient surveys , such as the palomar transient factory @xcite and pan - starrs1 @xcite ; and allowed for space missions ( e.g. , _ kepler _ ; * ? ? ?. Please generate the next two sentences of the article

* ) that continuously monitor more than 100,000 stars . the stellar discoveries from these surveys include revelations about rare stars , unusual explosive outcomes , and remarkably complex binaries .

Suppose that you have an abstract for a scientific paper: we exploit the recent observations of extremely metal - poor ( emp ) stars in the galactic halo and investigate the constraints on the initial mass function ( imf ) of the stellar population that left these low - mass survivors of @xmath0}\lesssim -2.5 $ ] and the chemical evolution that took part in . a high - mass nature of imf with the typical mass @xmath1 and the overwhelming contribution of low - mass members of binaries to the emp survivors are derived from the statistics of carbon - enriched emp stars with and without the enhancement of s - process elements ( komiya et al . 2007 , ) . that the same constraints are placed on the imf from the surface density of emp stars estimated from the surveys and the chemical evolution consistent with the metal yields of theoretical supernova models . apply the derived high - mass imf with the binary contribution metallicity distribution function ( mdf ) of emp stars not only for the shape but also for the number of emp stars . in particular , the scarcity of stars below @xmath0}\simeq -4 $ ] is naturally explained in terms of the hierarchical structure formation , and there is no indication of significant changes in the imf for the emp population . the present study indicates that 3 hmp / ump stars of @xmath0 } < -4 $ ] are the primordial stars that were born as the low - mass members of binaries before the host clouds were polluted by their own supernovae . . And you have already written the first three sentences of the full article: to reveal the nature of the extremely metal - poor ( emp ) stars in the galactic halo is the key to the understanding of the formation process of the galaxy as well as of the mechanism of star formation in the primordial and very metal - poor gas clouds . because of the very low abundances of iron and other metals , these stars are thought to be survivors from the early days , and hence , are expected to carry the precious information about the early universe when they were born while they reside in our nearby space . for a past decade , a lot of emp stars have been discovered by hk survey @xcite and hamburg / eso ( he s ) survey @xcite , which enables us to use halo emp stars as a probe into the early universe .. Please generate the next two sentences of the article

the number of known emp stars exceeds several hundreds even if we limit the metallicity range below @xmath0}\lesssim -2.5 $ ] @xcite . one of their observed characteristics is very low frequency of stars below the metallicity @xmath0}\simeq -4 $ ] . despite that more than @xmath2 stars have been registered in the metallicity range of @xmath3}\lesssim -3 $ ] by high - dispersion spectroscopy ( e.g. ,

Suppose that you have an abstract for a scientific paper: integration of the form @xmath0 , where @xmath1 is either @xmath2 or @xmath3 , is widely encountered in many engineering and scientific applications , such as those involving fourier or laplace transforms . often such integrals are approximated by a numerical integration over a finite domain @xmath4 , leaving a truncation error equal to the tail integration @xmath5 in addition to the discretization error . this paper describes a very simple , perhaps the simplest , end - point correction to approximate the tail integration , which significantly reduces the truncation error and thus increases the overall accuracy of the numerical integration , with virtually no extra computational effort . higher order correction terms and error estimates for the end - point correction formula are also derived . the effectiveness of this one - point correction formula is demonstrated through several examples . * keywords : * numerical integration , fourier transform , laplace transform , truncation error . . And you have already written the first three sentences of the full article: integration of the form @xmath6 , where @xmath1 is either @xmath2 or @xmath7 , is widely encountered in many engineering and scientific applications , such as those involving fourier or laplace transforms . often such integrals are approximated by numerical integrations over a finite domain @xmath4 , resulting in a truncation error @xmath8 , in addition to the discretization error . one example is a discrete fourier transform ( dft ) , where there is a truncation error due to cut - off in the tail , in addition to the discretization error . in theory. Please generate the next two sentences of the article

the cut - off error can always be reduced by extending the finite domain at the expense of computing time . however , in many cases a sufficiently long integration domain covering a very long tail can be computationally expensive , such as when the integrand @xmath9 itself is a semi - infinite integration ( e.g. forward fourier or laplace transform ) , or when the integrand decays to zero very slowly ( e.g. a heavy tailed density or its characteristic function ) . much work has been done to directly compute the tail integration in order to reduce the truncation error . examples include nonlinear transformation and extrapolation ( wynn 1956 , alaylioglu et al 1973 , sidi 1980 , 1982 , 1988 , levin and sidi 1981 ) and application of special or generalized quadratures ( longman 1956 , hurwitz and zweifel 1956 , bakhvalov and vasileva 1968 , piessens 1970 , piessens and haegemans 1973 , patterson 1976 , evans and webster 1997 , evans and chung 2007 ) , among many others .

Suppose that you have an abstract for a scientific paper: we present a detailed study of the transport and energetics of a brownian particle moving in a periodic potential in the presence of an adiabatic external periodic drive . the particle is considered to move in a medium with periodic space dependent friction with the same periodicity as that of the potential but with a phase lag . we obtain several results , most of them arising due to the medium being inhomogeneous and are sensitive to the phase lag . when the potential is symmetric we show that efficiency of energy transduction can be maximised as a function of noise strength or temperature . however , in the case of asymmtertic potential the temperature may or may not facilitate the energy conversion but current reversals can be obtained as a function of temperature and the amplitude of the periodic drive . the reentrant behaviour of current can also be seen as a function of phase lag . + pacs number(s ) : 05.40+j , 05.60+w , 82.20mj = 0.3 in = 0.6 in . And you have already written the first three sentences of the full article: the search for the possibility of unidirectional motion in a periodic system without the application of any obvious bias is of current research interest@xcite . such possibility requires the system to be out of equilibrium in order for the process to be consistent with the second law of thermodynamics . several physical models have been proposed to obtain such motion . in all. Please generate the next two sentences of the article

the models noise plays the central role . one of the most discussed models is the one in which an asymmetric periodic potential system is adiabatically rocked@xcite by applying constant forces @xmath0 and @xmath1 at regular intervals of time .

Suppose that you have an abstract for a scientific paper: a zero temperature dynamics of ising spin glasses and ferromagnets on random graphs of finite connectivity is considered , like granular media these systems have an extensive entropy of metastable states . we consider the problem of what energy a randomly prepared spin system falls to before becoming stuck in a metastable state . we then introduce a tapping mechanism , analogous to that of real experiments on granular media , this tapping , corresponding to flipping simultaneously any spin with probability @xmath0 , leads to stationary regime with a steady state energy @xmath1 . we explicitly solve this problem for the one dimensional ferromagnet and @xmath2 spin glass and carry out extensive numerical simulations for spin systems of higher connectivity . the link with the density of metastable states at fixed energy and the idea of edwards that one may construct a thermodynamics with a flat measure over metastable states is discussed . in addition our simulations on the ferromagnetic systems reveal a novel first order transition , whereas the usual thermodynamic transition on these graphs is second order . 0.5 cm pacs numbers : 05.20 , 75.10 nr , 81.05 rm . 2 . And you have already written the first three sentences of the full article: recently there has been much experimental and theoretical interest in the properties of granular media . in such systems the thermal energy available is not sufficient to allow the rearrangement of a single particle and hence the system is effectively at zero temperature in the thermal sense . the fact that the problem is not trivial lies in the fact that such systems have an exponentially large number of such metastable states , which may be also called blocked or jammed configurations .. Please generate the next two sentences of the article

edwards associated an entropy to these configurations @xmath3 where @xmath4 is the total number of metastable states of the system @xcite . it is reasonable to assume that in complex systems such as granular media @xmath5 is extensive meaning that @xmath6 where @xmath7 is the entropy per particle , alternatively one may work with an entropy per unit of volume which is clearly a more natural choice in granular media . because the system has an extensive number of blocked configurations , if it is prepared from a random initial state it will lower its energy via only energy lowering rearrangements until it becomes stuck in a metastable state .

Suppose that you have an abstract for a scientific paper: the attenuation of atmospheric cherenkov photons is dominated by two processes : rayleigh scattering from the molecular component and mie scattering from the aerosol component . aerosols are expected to contribute up to 30 wm@xmath0 to the emission profile of the atmosphere , equivalent to a difference of @xmath1c to the clear sky brightness temperature under normal conditions . here we investigate the aerosol contribution of the measured sky brightness temperature at the h.e.s.s . site ; compare it to effective changes in the telescope trigger rates ; and discuss how it can be used to provide an assessment of sky clarity that is unambiguously free of telescope systematics . address = department of physics , university of durham , durham , dh1 3le . u.k . address = lupm , un . montpellier ii cc-072 , place eugenie bataillon , 34095 montpellier , france . . And you have already written the first three sentences of the full article: the atmosphere is the most important part of the detector in ground - based gamma - ray astronomy , but it is also the part that has the greatest systematic uncertainty and over which we have the least control . it falls upon us to instead monitor and characterise the atmospheric conditions at the time of observations so that we can either feed this information into monte carlo simulations or reject data when conditions go out of acceptable parameters . after being generated in the upper atmosphere cherenkov light will either reach the ground or be attenuated through the process of rayleigh scattering on the molecular component of the atmosphere , or mie scattering on the aerosol component ( variously dust .. Please generate the next two sentences of the article

silicates , pollens , etc ) . the molecular component tends to change relativiely slowly , through seasonal variations ; whereas the aerosol component can change more rapidly , depending on eg wind conditions .

Suppose that you have an abstract for a scientific paper: recently it was shown that kink baryons and kink - antikink scattering in the massless gross - neveu model are closely related to one- and two - soliton solutions of the sinh - gordon equation . here we generalize these findings to the case of @xmath0 kinks and antikinks . using the known @xmath0 soliton solution of the sinh - gordon equation , we solve the general @xmath0 kink - antikink scattering problem in the large @xmath1 gross - neveu model analytically , mapping the time - dependent hartree - fock approach onto inverse scattering theory . . And you have already written the first three sentences of the full article: in this paper , we continue our study of the simplest gross - neveu ( gn ) model @xcite , a 1 + 1 dimensional model field theory of @xmath1 species of massless , self - interacting dirac fermions with lagrangian @xmath2 we restrict ourselves from the outset to the t hooft limit @xmath3 const . semiclassical methods have revealed a number of fascinating properties of this model over the years , see the review articles @xcite and references therein . a key quantity in these studies is the scalar mean field @xmath4 .. Please generate the next two sentences of the article

it plays a role similar to witten s master field " in large @xmath1 gauge theories @xcite , namely as saddle point of the functional integral from which all observables can be computed . for fermions in the large @xmath1 limit , it can be identified with the self - consistent hartree - fock ( hf ) potential .

Suppose that you have an abstract for a scientific paper: -0.0 cm we present a systematic study of the properties of pure hadronic and hybrid compact stars . the nuclear equation of state ( eos ) for @xmath0-equilibrated neutron star matter was obtained using density dependent effective nucleon - nucleon interaction which satisfies the constraints from the observed flow data from heavy - ion collisions . the energy density of quark matter is lower than that of this nuclear eos at higher densities implying the possibility of transition to quark matter inside the core . we solve the einstein s equations for rotating stars using pure nuclear matter and quark core . the @xmath0- equilibrated neutron star matter with a thin crust is able to describe highly massive compact stars but find that the nuclear to quark matter deconfinement transition inside neutron stars causes reduction in their masses . recent observations of the binary millisecond pulsar j1614 - 2230 by p. b. demorest et al . @xcite suggest that the masses lie within 1.97@xmath10.04 m@xmath2 where m@xmath2 is the solar mass . in conformity with recent observations , pure nucleonic eos determines that the maximum mass of ns rotating with frequency below r - mode instability is @xmath31.95 m@xmath2 with radius @xmath310 kilometers . although compact stars with quark cores rotating with kepler s frequency have masses up to @xmath32 m@xmath2 , but if the maximum frequency is limited by the r - mode instability , the maximum mass @xmath31.7 m@xmath2 turns out to be lower than the observed mass of 1.97@xmath10.04 m@xmath2 , by far the highest yet measured with such certainty , implying exclusion of quark cores for such massive pulsars . 0.2 cm _ pacs numbers _ : 26.60.-c , 21.65.cd , 21.65.ef , 26.60.kp , 12.38.-t , 12.39.-x , 21.65.qr -0.0 cm and -0.0 cm -0.29 cm -0.0 cm neutron star ; nuclear eos ; quark eos ; hybrid star . -0.0 . And you have already written the first three sentences of the full article: the mass - radius relationship of neutron stars ( nss ) is of prime importance to understand the high - density low - temperature regime of the hadronic equation of state ( eos ) . depending on this relationship , certain models for the hadronic eos can either be confirmed or ruled out . several attempts have been made on measuring the radii and masses of nss to constrain the uncertainties in the high density behavior of the eos .. Please generate the next two sentences of the article

the observations on double nss @xcite , glitches in radio pulsars @xcite , thermal emission @xcite from accreting nss and from millisecond x - ray pulsars lead to constraints on mass - radius relationship of nss . recently the pressure of neutron star matter at supranuclear density is measured by zel et al .

Suppose that you have an abstract for a scientific paper: we report measurements of the exclusive electroproduction of @xmath0 and @xmath1 final states from an unpolarized proton target using the clas detector at the thomas jefferson national accelerator facility . the separated structure functions @xmath2 , @xmath3 , @xmath4 , and @xmath5 were extracted from the @xmath6-dependent differential cross sections acquired with a longitudinally polarized 5.499 gev electron beam . the data span a broad range of momentum transfers @xmath7 from 1.4 to 3.9 gev@xmath8 , invariant energy @xmath9 from threshold to 2.6 gev , and nearly the full center - of - mass angular range of the kaon . the separated structure functions provide an unprecedented data sample , which in conjunction with other meson photo- and electroproduction data , will help to constrain the higher - level analyses being performed to search for missing baryon resonances . . And you have already written the first three sentences of the full article: a complete mapping of the nucleon excitation spectrum is the key to a detailed understanding of the effective degrees of freedom of the nucleon and its associated dynamics . the most comprehensive predictions of this spectrum have come from various implementations of the constituent quark model incorporating broken su(6 ) symmetry @xcite . additional dynamical contributions from gluonic excitations in the wavefunction may also play a central role @xcite and resonances may be dynamically generated through baryon - meson interactions @xcite .. Please generate the next two sentences of the article

quark model calculations of the nucleon spectrum have predicted more states than have been seen experimentally @xcite . this has been termed the `` missing '' resonance problem , and the existence of these states is tied in directly with the underlying degrees of freedom of the nucleon that govern hadronic production at moderate energies @xcite .

Suppose that you have an abstract for a scientific paper: to elucidate the mechanism by which chaos is generated in the shell model , we compare three random matrix ensembles : the gaussian orthogonal ensemble , french s two body embedded ensemble , and the two body random ensemble ( tbre ) of the shell model . of these , the last two take account of the two body nature of the residual interaction , and only the last , of the existence of conserved quantum numbers like spin , isospin , and parity . while the number of independent random variables decreases drastically as we follow this sequence , the complexity of the ( fixed ) matrices which support the random variables , increases even more . in that sense we can say that in the tbre , chaos is largely due to the existence of ( an incomplete set of ) symmetries . shell model , symmetry , complexity 21.10.-k , 05.45.mt , 24.60.-k . And you have already written the first three sentences of the full article: the analysis of nuclear spectra has produced ample evidence for chaotic motion . indeed , near neutron threshold , the spectra of medium weight and heavy nuclei display fluctuations which agree with those of random matrices drawn from the gaussian orthogonal ensemble ( goe ) @xcite . similar agreement has been found for nuclei in the @xmath0shell ( both in experimental data @xcite and in shell model calculations @xcite ) , and in the ground state domain of heavier nuclei @xcite , although here there exists strong evidence , too , for regular motion as predicted by the shell model and the collective models . calculations in ce @xcite have produced similar evidence for chaotic motion in atoms . thus , chaos appears to be an ubiquitous feature of interacting many . Please generate the next two sentences of the article

body systems . what is the origin of this behavior ? in the present paper , we address aspects of this question . we do so using the nuclear shell model , a theory with a mean field and a residual two body effective interaction @xmath1 .

Suppose that you have an abstract for a scientific paper: the field of complex self - assembly is moving toward the design of multi - particle structures consisting of thousands of distinct building blocks . to exploit the potential benefits of structures with such ` addressable complexity , ' we need to understand the factors that optimize the yield and the kinetics of self - assembly . here we use a simple theoretical method to explain the key features responsible for the unexpected success of dna - brick experiments , which are currently the only demonstration of reliable self - assembly with such a large number of components . simulations confirm that our theory accurately predicts the narrow temperature window in which error - free assembly can occur . even more strikingly , our theory predicts that correct assembly of the complete structure may require a time - dependent experimental protocol . furthermore , we predict that low coordination numbers result in non - classical nucleation behavior , which we find to be essential for achieving optimal nucleation kinetics under mild growth conditions . we also show that , rather surprisingly , the use of heterogeneous bond energies improves the nucleation kinetics and in fact appears to be necessary for assembling certain intricate three - dimensional structures . this observation makes it possible to sculpt nucleation pathways by tuning the distribution of interaction strengths . these insights not only suggest how to improve the design of structures based on dna bricks , but also point the way toward the creation of a much wider class of chemical or colloidal structures with addressable complexity . recent experiments with short pieces of single - stranded dna@xcite have shown that it is possible to assemble well - defined molecular superstructures from a single solution with more than merely a handful of distinct building blocks . these experiments use complementary dna sequences to encode an addressable structure@xcite in which each distinct single - stranded ` brick ' belongs in a specific.... And you have already written the first three sentences of the full article: in constructing a model for the self - assembly of addressable structures , we note that the designed interactions should be much stronger than any attractive interactions between subunits that are not adjacent in a correctly assembled structure . the designed interactions that stabilize the target structure can be described by a connectivity graph , @xmath0 , in which each vertex represents a distinct subunit and each edge indicates a correct bond . this graph allows us to describe the connectivity of the structure independently of the geometry and spatial organization of the building blocks . for structures constructed from dna bricks ,. Please generate the next two sentences of the article

the edges of @xmath0 indicate the hybridization of dna strands with complementary sequences that are adjacent in the target structure . an example three - dimensional dna - brick structure is shown along with its connectivity graph in figures [ fig : ramp_example]a and [ fig : ramp_example]b . in an ideal solution with exclusively designed interactions , the subunits assemble into clusters in which all allowed bonds are encoded in the connectivity graph of the target structure . in order to compute the free - energy difference between a particular cluster size and the unbonded single - stranded bricks

Suppose that you have an abstract for a scientific paper: we use exact diagonalization to study the breakdown of many - body localization in a strongly disordered and interacting system coupled to a thermalizing environment . we show that the many - body level statistics cross over from poisson to goe , and the localized eigenstates thermalize , with the crossover coupling decreasing with the size of the bath in a manner consistent with the hypothesis that an infinitesimally small coupling to a thermodynamic bath should destroy localization of the eigenstates . however , signatures of incomplete localization survive in spectral functions of local operators even when the coupling to the environment is sufficient to thermalize the eigenstates . these include a discrete spectrum and a gap at zero frequency . both features are washed out by line broadening as one increases the coupling to the bath . we also determine how the line broadening scales with coupling to the bath . isolated quantum systems with quenched disorder can enter a ` localized ' regime where they fail to ever reach thermodynamic equilibrium @xcite . while we have an essentially complete understanding of localization in non - interacting systems @xcite , the theory of many - body localization ( mbl ) is still under construction @xcite . numerical investigations using exact diagonalization @xcite _ do _ indicate that all eigenstates of a strongly interacting disordered system can be localized . most of the theoretical research so far has been in the limit of a perfectly isolated system . however , experimental tests of mbl ( @xcite ) will always include some finite coupling to the environment . what then can we expect to see in experiments designed to probe many body localization ? a recent theory of mbl systems weakly coupled to heat baths proposed that while eigenstates are delocalized by an infinitesimally weak coupling to a heat bath , signatures of localization persist in spectral functions of local operators for weak coupling to a bath @xcite . this theory has yet.... And you have already written the first three sentences of the full article: in this appendix , we explain how the line width was extracted from the numerical data . we begin by determining the spectral function , defined by @xmath115 this consists of a set of delta functions . we then define the integrated spectral function @xmath116 .. Please generate the next two sentences of the article

this consists of a set of step functions ( see fig . [ steps](a ) ) . for each step

Suppose that you have an abstract for a scientific paper: we apply a recently proposed density functional for mixtures of parallel hard cylinders , based on rosenfeld s fundamental measure theory , to study the effect of length - polydispersity on the relative stability between the smectic and columnar liquid crystal phases . to this purpose we derive from this functional an expression for the direct correlation function and use it to perform a bifurcation analysis . we compare the results with those obtained with a second and a third virial approximation of this function . all three approximations lead to the same conclusion : there is a terminal polydispersity beyond which the smectic phase is less stable than the columnar phase . this result is in agreement with previous monte carlo simulations conducted on a freely rotating length - polydisperse hard spherocylinder fluid , although the theories always overestimate the terminal polydispersity because the nematic - columnar phase transition is first order and exhibits a wide coexistence gap . both , the fundamental - measure functional and the third virial approximation , predict a metastable nematic - nematic demixing . conversely , according to second virial approximation this demixing might be stable at high values of the polydispersity , something that is observed neither in simulations nor in experiments . the results of the fundamental - measure functional are quantitatively superior to those obtained from the other two approximations . thus this functional provides a promising route to map out the full phase diagram of this system . . And you have already written the first three sentences of the full article: simple fluids are made of atomic particles . these are identical , spherically symmetric particles which interact via a well defined interaction potential of which the lennard - jones formula provides a very good approximation . the classic states of matter are a consequence of this nature : interaction decays fast at long distance , hence we have a gas when the density is low ; the potential has an attractive well at short distances , and this causes the liquid when the density is high enough ; and finally , the interaction becomes strongly repulsive at very short distances and this makes the fluid freeze into a crystalline structure when it becomes very dense , due to entropic considerations ( see e.g. @xcite for further details ) .. Please generate the next two sentences of the article

in contrast to the ` simple fluid ' paradigm provided by atomic fluids we have colloids . these are suspensions of big around one micron particles , which are actually aggregates of smaller particles , in a solvent which may also contain other elements ( like ions , polymers , etc . ) . because of this , particles are all different in shape , size , charge , etc . , and the interactions are the result of adding up the separate contribution of each of the elements of the aggregate that we call a colloidal particle , as well as the entropic forces that the solvent and its constituents exert on them @xcite .

Suppose that you have an abstract for a scientific paper: we report results of rxte observations of psr b1951 + 32 using the pca instrument for 19k seconds during 1996 march 24th . we applied the contemporaneous radio ephemeris and various statistical tests to search for evidence of pulsation . these analyses yield intriguing yet inconclusive evidence for the presence of the pulsation in the time series : confidence level for the presence of pulsation is 94.5% in the 2.0 - 4.8 kev band and 97.6% in the 4.8 - 6.3 kev band based on the @xmath0-test . under the premise of non - detection of pulsation , we derive estimated 2-@xmath1 upper limits for the pulsed flux to be @xmath2 in the 2.0 - 4.8 kev band , @xmath3 in the 4.8 - 8.5 kev band , and @xmath4 in the 8.5 - 13.0 kev band . these upper limits are consistent with the trend of spectral turn - over from high - energy gamma - ray emission as suggested by the osse upper limit . such turn - over strongly suggests the outer magnetosphere as the emission site for pulsed gamma - rays . these rxte upper limits for x - ray pulsation are , on the other hand , not consistent with the extrapolation of reported power - law spectra from the point source observed by rosat in the 0.1 - 2.4 kev band , assuming a constant pulse fraction : the pulsed soft x - ray emission detected by rosat must follow a much softer spectrum than that of the overall point source . . And you have already written the first three sentences of the full article: the pulsar psr b1951 + 32 , located at the center of the morphologically peculiar radio nebula ctb 80 , is a 39.5-msec radio pulsar ( clifton et al . 1987 ; kulkarni et al . 1988 ) with a characteristic age of @xmath5 yr and an inferred surface dipole magnetic field of @xmath6 g. an x - ray point source was observed within the x - ray nebula related to the radio core of ctb 80 ( becker , helfand & szymkowiak 1982 ; seward 1983 ; wang & seward 1984 ) .. Please generate the next two sentences of the article

search for x - ray pulsation from this source with exosat yielded inconclusive evidence for pulsation ( confidence level of 97% , by gelman & buccheri 1987 , and 93% by angelini et al . the pulsed emission was detected by rosat at a 99% confidence level ( safi - harb , gelman & finley 1995 ) , which shows a single peak roughly consistent in phase with the radio emission .

Suppose that you have an abstract for a scientific paper: linear diamagnetism is predicted in the vortex - liquid phase of layered superconductors at temperatures just below the mean - field phase transition on the basis of a high - temperature analysis of the corresponding frustrated @xmath0 model . the diamagnetic susceptibility , and the nernst signal by implication , is found to vanish with temperature as @xmath1 in the vicinity of the meanfield transition at @xmath2 . quantitative agreement with recent experimental observations of a diamagnetic signal in the vortex - liquid phase of high - temperature superconductors is obtained . . And you have already written the first three sentences of the full article: the abrikosov vortex lattice melts into an extended vortex - liquid phase in high - temperature superconductors subject to an external magnetic field oriented perpendicular to the conducting copper - oxygen planes that make them up@xcite@xcite . the large size in temperature and magnetic field of the vortex - liquid phase can be attributed to such layer anisotropy@xcite@xcite@xcite . a cross - over from a vortex - line liquid at temperatures just above the melting point of the abrikosov vortex lattice to a decoupled vortex liquid at higher temperature that shows negligible correlations of the superconducting order parameter across layers is predicted if the vortex lattice in isolated layers melts through a continuous or a weakly first - order phase transition@xcite . such dimensional cross - over. Please generate the next two sentences of the article

is observed experimentally in electronic transport studies of the vortex - liquid phase in moderately anisotropic high - temperature superconductors@xcite . the abrikosov vortex lattice is predicted to sublimate directly into a decoupled vortex liquid at large enough layer anisotropy , on the other hand , if the vortex lattice in isolated layers melts through a first - order phase transition@xcite .

Suppose that you have an abstract for a scientific paper: a detailed study is presented of the search for higgs bosons in the b - decay channel in the central exclusive production process at the lhc . we present results for proton tagging detectors at both 220 m and 420 m around atlas or cms . we consider two benchmark scenarios ; a standard model ( sm ) higgs boson and the @xmath0 scenario of the minimal supersymmetric standard model ( mssm ) . detector acceptance , smearing and event trigger strategies are considered . we find that the sm higgs will be challenging to observe in the b - jet channel without improvements to the currently proposed experimental configuration , but a neutral scalar mssm higgs boson could be observable in the b - jet channel with a significance of @xmath1 or greater within three years of data taking at all luminosities between @xmath2 @xmath3 s@xmath4 and @xmath5 @xmath3 s@xmath4 , and at @xmath6 or greater after three years in certain scenarios . . And you have already written the first three sentences of the full article: the physics potential of forward proton tagging at the lhc has attracted a great deal of attention in recent years @xcite . a main focus of interest is the central exclusive production ( cep ) process , @xmath7 , in which the protons remain intact and the central system @xmath8 is separated from the outgoing protons by a large rapidity gap . to a very good approximation , @xmath8 is constrained to be in a colour singlet , @xmath9 , state .. Please generate the next two sentences of the article

observation of any particle , such as a standard model higgs boson , in the central exclusive channel would therefore provide a direct observation of its quantum numbers . furthermore , by detecting the outgoing protons and measuring their energy loss accurately , it is possible to measure the mass of the centrally produced particle regardless of its decay products @xcite .

Suppose that you have an abstract for a scientific paper: a bound - state field theory approach to muonic hydrogen is set up using a variant of the furry representation in which the lowest - order hamiltonian describes a muon in the presence of a point coulomb field , but the origin of the binding field is taken to be three charged quarks in the proton which are modeled as dirac particles that move freely within a spherical well . bound - state field theory techniques are used to evaluate one- and two - photon effects . particular attention is paid to two - photon exchange diagrams , which include the effect of proton polarizability . in addition the modification of the electromagnetic self energy of the proton by the electric field of the muon is examined . finally , the model is used to carry out a calculation of the static electric polarizability of the proton . # 1#2 # 1#2 # 1 . And you have already written the first three sentences of the full article: one of the simplest ways to model the proton is as three very light quarks confined in a spherical well . choosing the radius of the well to be @xmath0 fm leads to moderately good agreement with experiment for its electromagnetic properties , such as the charge radius , magnetic moment , and static electric and magnetic polarizabilities . this model , a simplified version of the mit bag model @xcite , will be referred to in the following as the static - well model .. Please generate the next two sentences of the article

it allows an alternative approach to the calculation of the electromagnetic properties of the proton , generally treated with methods quite different in character , that uses the methods of conventional bound - state qed . the latter theory is characterized by wave functions that satisfy the dirac equation in an external field along with electron propagators defined in terms of the same field .

Suppose that you have an abstract for a scientific paper: 2 is a second generation microlensing experiment operating since mid-1996 at the european southern observatory ( eso ) at la silla ( chile ) . we present the two year analysis from our microlensing search towards the small magellanic cloud ( ) , and report on the intensive observation of the caustic crossing event -98 - 1 and the limit derived on the location of the lens . we also give preliminary results from our search towards the large magellanic cloud ( ) ; 25 square degrees are being analyzed and two candidates have been found . this allows us to set another limit on the halo mass fraction comprised of compact objects . . And you have already written the first three sentences of the full article: a few years after paczyski s proposal ( paczyski 1986 ) , the collaboration engaged in long term microlensing observations towards the magellanic clouds in order to probe the galactic halo . 1 and experiments set strong limits on the maximum contribution of low mass objects to the halo of the milky way ( alcock et al . 1998 ) . towards the , the optical depth has been estimated by as @xmath0 , from 8 events ( alcock et al .. Please generate the next two sentences of the article

1997a ) ; the time scales associated with these events indicate high mass lenses ( @xmath1 ) that are not observed visually . based on 2 candidates , 1 gave an upper limit on the halo mass fraction in s ( ansari et al .

Suppose that you have an abstract for a scientific paper: we discuss hall effect and power dissipation in chiral @xmath0-wave superconductors near kosterlitz - thouless transition in the absence of applied magnetic field . in bound pair dynamics picture , nonzero hall conductivity emerges when vortex - antivortex bound pair polarization has a component transverse to the direction of external perturbation . such effect arises from the broken time reversal symmetry nature of a chiral @xmath0-wave superconducting state and does not require an applied magnetic field . a frequency - dependent matrix dielectric function @xmath1 is derived to describe the screening effect due to the pair polarization . quantities related to the hall conductivity and power dissipation , denoted as @xmath2 and @xmath3 , are investigated in frequency and temperature domain . the imaginary part of the former can show peak structure and sign reversal as a function of frequency close to transition temperature , as well as in the temperature domain at various fixed frequencies . the latter shows peak structure near transition temperature . these features are attributed to pair - size - dependent longitudinal and transverse response function of bound pairs . consequences due to free vortex dynamics and the resulting total conductivity tensor @xmath4 are also discussed . . And you have already written the first three sentences of the full article: zero - field hall effect in chiral @xmath0-wave superconductors ( scs ) has drawn much attention in literature recently . @xcite because of the nature of broken time reversal ( @xmath5 ) symmetry , a nonzero hall conductivity can be possible in a chiral @xmath0-wave sc . indeed , it has already been shown that spontaneous hall effect could arise from the intrinsic angular momentum of cooper pairs @xcite as well as from the spontaneous surface current .. Please generate the next two sentences of the article

@xcite more recently , hall conductivity due to impurity effect @xcite or to multiband sc structure @xcite was also studied , which could give possible explanation to the observed polar kerr effect in the superconducting state of sr@xmath6ruo@xmath7 . @xcite in this work , we address the zero - field hall effect in a chiral @xmath0-wave sc originating from another mechanism , namely the vortex dynamics near kosterlitz - thouless ( kt ) transition . in two - dimensional ( 2d ) superfluid ( sf ) or sc films , quantized vortices

Suppose that you have an abstract for a scientific paper: we study character varieties of symmetric knots and their reductions @xmath0 . we observe that the varieties present a different behaviour according to whether the knots admit a free or periodic symmetry . _ ams classification : _ primary 57m25 ; secondary 20c99 ; 57m50 . _ keywords : _ character varieties , hyperbolic knots , symmetries . . And you have already written the first three sentences of the full article: character varieties of @xmath1-manifold groups provide a useful tool in understanding the geometric structures of manifolds and notably the presence of essential surfaces . in this paper we wish to investigate @xmath2-character varieties of symmetric hyperbolic knots in order to pinpoint specific behaviours related to the presence of free or periodic symmetries . we will be mostly concerned with symmetries of odd prime order and we will concentrate our attention to the subvariety of the character variety which is invariant by the action of the symmetry ( see section [ s : invariantch ] for a precise definition of this action and of the invariant subvariety ) . as already observed in @xcite , the excellent component of the character variety containing the character of the holonomy representation is invariant by the symmetry , since the symmetry can be chosen to act as a hyperbolic isometry of the complement of the knot .. Please generate the next two sentences of the article

hilden , lozano , and montesinos also observed that the invariant subvariety of a hyperbolic symmetric ( more specifically , periodic ) knot can be sometimes easier to determine than the whole variety . this follows from the fact that the invariant subvariety can be computed using the character variety of a two - component hyperbolic link .

Suppose that you have an abstract for a scientific paper: motivated by questions about square - free monomial ideals in polynomial rings , in 2010 francisco et al . conjectured that for every positive integer @xmath0 and every @xmath0-critical ( i.e. , critically @xmath0-chromatic ) graph , there is a set of vertices whose replication produces a @xmath1-critical graph . ( the replication of a set @xmath2 of vertices of a graph is the operation that adds a copy of each vertex @xmath3 in @xmath2 , one at a time , and connects it to @xmath3 and all its neighbours . ) we disprove the conjecture by providing an infinite family of counterexamples . furthermore , the smallest member of the family answers a question of herzog and hibi concerning the depth functions of square - free monomial ideals in polynomial rings , and a related question on the persistence property of such ideals . . And you have already written the first three sentences of the full article: an investigation of the properties of square - free monomial ideals in polynomial rings led francisco et al . @xcite to an interesting question about replication in colour - critical graphs that we answer in the present paper . in the area of graph colourings , constructions and properties of colour - critical graphs are a classical subject ( see , e.g. , ( * ? ? ?. Please generate the next two sentences of the article

* section 14.2 ) ) . the replication of a set of vertices , whose definition we will recall shortly , is a natural operation in this context .

Suppose that you have an abstract for a scientific paper: the universal curve @xmath0 of nuclear photoabsorption is investigated within a fermi gas model of nuclear matter . an energy range from pion threshold up to 400 mev is considered . the interactions between nucleon , pion , @xmath1-isobar and photon are considered in the non - relativistic approximation with corrections of the order @xmath2 taken into account with respect to proton mass . analytical expressions are obtained , in which the influence of nuclear correlations , two - nucleon contributions and relativistic corrections is studied explicitely . an extension of the model calculation to nucleon knock - out reactions is discussed . contribution of real and virtual pions to nuclear photoabsorption at intermediate energies + m .- th.htt@xmath3 , a.i.milstein@xmath4 and m.schumacher@xmath3 + ( a ) ii . institut der universitt gttingen , gttingen , germany \(b ) budker institute of nuclear physics , 630090 novosibirsk , russia 0em 1.5ex plus 0.5ex minus 0.5ex _ pacs code : _ 25.20.-x _ keywords : _ photoabsorption , mesonic exchange currents , nuclear correlation functions . And you have already written the first three sentences of the full article: the phenomenology of nuclear photoabsorption is governed by two characteristic features . first , all nuclei with mass numbers @xmath5 ranging from 10 to more than 200 obey the same fundamental curve @xmath6 for the total photoabsorption cross section devided by @xmath5 as a function of the photon energy @xmath7 . second , the @xmath1-isobar excitation of the nucleon is responsible for the main properties of this curve in the energy region between 200 and 400 mev .. Please generate the next two sentences of the article

models , which focus on the behaviour of the @xmath1-isobar in a nuclear environment , namely the @xmath1-hole calculations @xcite , have proven to be highly successful in explaining the experimental findings for pion scattering processes @xcite . indeed , on grounds of the @xmath1-hole formalism a wide variety of pion - nucleus reactions can be described within one consistent framework @xcite . in the case of photonuclear reactions , however , serious descrepancies remain , which partially have been accounted for by including non - resonant background terms @xcite . nevertheless , such a procedure , in particular for nuclear photoabsorption , either leads to contradictions with previous @xmath1-hole results or lacks the complete agreement with experimental data @xcite .

Suppose that you have an abstract for a scientific paper: dwarf galaxies are good candidates to investigate the nature of dark matter , because their kinematics are dominated by this component down to small galactocentric radii . we present here the results of detailed kinematic analysis and mass modelling of the orion dwarf galaxy , for which we derive a high quality and high resolution rotation curve that contains negligible non - circular motions and we correct it for the asymmetric drift . moreover , we leverage the proximity ( d @xmath0 5.4 kpc ) and convenient inclination ( 47@xmath1 ) to produce reliable mass models of this system . we find that the universal rotation curve mass model ( freeman disk @xmath2 burkert halo @xmath2 gas disk ) fits the observational data accurately . in contrast , the nfw halo + freeman disk @xmath2 gas disk mass model is unable to reproduce the observed rotation curve , a common outcome in dwarf galaxies . finally , we attempt to fit the data with a modified newtonian dynamics ( mond ) prescription . with the present data and with the present assumptions on distance , stellar mass , constant inclination and reliability of the gaseous mass , the mond `` amplification '' of the baryonic component appears to be too small to mimic the required `` dark component '' . the orion dwarf reveals a cored dm density distribution and a possible tension between observations and the canonical mond formalism . [ firstpage ] dark matter ; galaxy : orion dwarf ; mass profiles . And you have already written the first three sentences of the full article: the measurement of the rotation curves ( rcs ) of disk galaxies is a powerful tool to investigate the nature of dark matter ( dm ) , including its content relative to the baryonic components and their distributions . in particular , dwarf galaxies are good candidates to reach this aim as their kinematics are generally dominated by the dark component , down to small galactocentric radii @xcite . this leads to a reliable measurement of the dynamical contribution of the dm to the rc and hence of its density profile . therefore , a dwarf galaxy like the orion dwarf provides us with an important test as to whether dm density profiles arising in @xmath3 cold dark matter ( @xmath3cdm ) numerical simulations @xcite are compatible with those detected in actual dm halos around galaxies .. Please generate the next two sentences of the article

let us comment that nfw profile arises from pure n - body dm simulations . it is well known that , as effect of the baryonic infall in the cosmological dm halos and of the subsequest process of stellar disk formation , shallower profiles of the dm halo may arise ( see @xcite ) .

Suppose that you have an abstract for a scientific paper: the very forward proton spectrometer ( vfps ) of the h1 experiment at hera is collecting data since 2005 . the fiber detectors in the roman pots located at 218 and 222 m downstream from the h1 interaction point , tag and measure diffractively scattered protons with a high acceptance in the @xmath0 range [ 0.01 , 0.025 ] . the experimental set up and the spectrometer tagging performance using diffractive events collected during 2006 and 2007 are discussed . . And you have already written the first three sentences of the full article: in recent years considerable progress has been achieved in the partonic interpretations of diffractive processes in @xmath1 collisions ( see e.g. @xcite ) , most of diffractive studies performed up to now at hera have been based on the characteristic presence of a rapidity gap in the diffractive final state . the precision of this method is limited by the uncertainty related to the presence of dissociated proton background events . the only precise and unambiguous way of studying diffraction is by tagging the diffracted proton and measuring its four momentum by means of a proton spectrometer . such devices have been used by the h1 and zeus collaborations and have delivered interesting results , but their acceptances are small , with the result that the collected statistics are limited and large systematic errors affect the measurements . to fully profit from the hera luminosity upgrade in the study of diffraction after the year 2003 , a very forward proton spectrometer ( vfps ) which identifies and measures the momentum of the diffracted proton with a high acceptance has therefore been installed by h1 .. Please generate the next two sentences of the article

this contribution reports the vfps tagging performance using diffractive events collected during hera running at high energy ( 27.5 gev for the electron / positron beam and 920 gev for the proton ) in 2006 and 2007 . the vfps @xcite is a set of two `` roman pots '' located at 118 m and 222 m downstream of the h1 interaction point .

Suppose that you have an abstract for a scientific paper: results are reported from a joint analysis of phase i and phase ii data from the sudbury neutrino observatory . the effective electron kinetic energy threshold used is @xmath0 mev , the lowest analysis threshold yet achieved with water cherenkov detector data . in units of @xmath1 @xmath2 s@xmath3 , the total flux of active - flavor neutrinos from @xmath4b decay in the sun measured using the neutral current ( nc ) reaction of neutrinos on deuterons , with no constraint on the @xmath4b neutrino energy spectrum , is found to be @xmath5 these uncertainties are more than a factor of two smaller than previously published results . also presented are the spectra of recoil electrons from the charged current reaction of neutrinos on deuterons and the elastic scattering of electrons . a fit to the sno data in which the free parameters directly describe the total @xmath4b neutrino flux and the energy - dependent @xmath6 survival probability provides a measure of the total @xmath4b neutrino flux @xmath7 . combining these new results with results of all other solar experiments and the kamland reactor experiment yields best - fit values of the mixing parameters of @xmath8 degrees and @xmath9 ev@xmath10 . the global value of @xmath11 is extracted to a precision of @xmath12% . in a three - flavor analysis the best fit value of @xmath13 is @xmath14 . this implies an upper bound of @xmath15 ( 95% c.l . ) . . And you have already written the first three sentences of the full article: it is by now well - established that neutrinos are massive and mixed , and that these properties lead to the oscillations observed in measurements of neutrinos produced in the sun @xcite@xcite , in the atmosphere @xcite , by accelerators @xcite , and by reactors @xcite . the mixing model predicts not only neutrino oscillations in vacuum , but also the effects of matter on the oscillation probabilities ( the ` msw ' effect ) @xcite . to date , the effects of matter have only been studied in the solar sector , where the neutrinos passage through the core of both the sun and the earth can produce detectable effects . the model predicts three observable consequences for solar neutrinos : a suppression of the @xmath6 survival probability below the average vacuum value of @xmath16 for high - energy ( @xmath4b ) neutrinos , a transition region between matter - dominated and vacuum - dominated oscillations , and a regeneration of @xmath6s as the neutrinos pass through the core of the earth ( the day / night effect ) .. Please generate the next two sentences of the article

in addition to improved precision in the extraction of the total flux of @xmath4b neutrinos from the sun , an advantage of the low energy threshold analysis ( leta ) presented here is the enhanced ability to explore the msw - predicted transition region and , in addition , more stringent testing of theories of non - standard interactions that affect the shape and position of the predicted rise in survival probability @xcite@xcite . we present in this article a joint analysis of the data from the first two data acquisition phases of the sudbury neutrino observatory ( sno ) , down to an effective electron kinetic energy of @xmath0 mev , the lowest analysis energy threshold yet achieved for the extraction of neutrino signals with the water cherenkov technique .

Suppose that you have an abstract for a scientific paper: in this paper we present the results of @xmath0-body simulations with a scalar field coupled differently to cold dark matter ( cdm ) and baryons . the scalar field potential and coupling function are chosen such that the scalar field acquires a heavy mass in regions with high cdm density and thus behaves like a chameleon . we focus on how the existence of the scalar field affects the formation of nonlinear large - scale structure , and how the different couplings of the scalar field to baryons and cdm particles lead to different distributions and evolutions for these two matter species , both on large scales and inside virialized halos . as expected , the baryon - cdm segregation increases in regions where the fifth force is strong , and little segregation in dense regions . we also introduce an approximation method to identify the virialized halos in coupled scalar field models which takes into account the scalar field coupling and which is easy to implement numerically . it is find that the chameleon nature of the scalar field makes the internal density profiles of halos dependent on the environment in a very nontrivial way . . And you have already written the first three sentences of the full article: the origin and nature of the dark energy @xcite is one of the most difficult challenges facing physicists and cosmologists now . among all the proposed models to tackle this problem , a scalar field is perhaps the most popular one up to now . the scalar field , denoted by @xmath1 , might only interact with other matter species through gravity , or have a coupling to normal matter and therefore producing a fifth force on matter particles .. Please generate the next two sentences of the article

this latter idea has seen a lot of interests in recent years , in the light that such a coupling could potentially alleviate the coincidence problem of dark energy @xcite and that it is commonly predicted by low energy effective theories from a fundamental theory . nevertheless , if there is a coupling between the scalar field and baryonic particles , then stringent experimental constraints might be placed on the fifth force on the latter provided that the scalar field mass is very light ( which is needed for the dark energy ) .

Suppose that you have an abstract for a scientific paper: in this paper , we first summarize the results of a large - scale double - blind tests campaign carried out for the realistic estimation of the gaia potential in detecting and measuring planetary systems . then , we put the identified capabilities in context by highlighting the unique contribution that the gaia exoplanet discoveries will be able to bring to the science of extrasolar planets during the next decade . . And you have already written the first three sentences of the full article: despite a few important successes ( e.g. , bean et al . 2007 , and references therein ) , astrometric measurements with mas precision have so far proved of limited utility when employed as either a follow - up tool or to independently search for planetary mass companions orbiting nearby stars ( see for example sozzetti 2005 , and references therein ) . in several past exploratory works ( casertano et al . 1996 ; lattanzi et al . 1997 , 2000 ; sozzetti et al 2001 , 2003 ) , we have shown in some detail what space - borne astrometric observatories with @xmath0as - level precision , such as gaia ( perryman et al .. Please generate the next two sentences of the article

2001 ) , can achieve in terms of search , detection and measurement of extrasolar planets of mass ranging from jupiter - like to earth - like . in those studies we adopted a qualitatively correct description of the measurements that each mission will carry out , and we estimated detection probabilities and orbital parameters using realistic , non - linear least squares fits to those measurements . those exploratory studies , however , need updating and improvements . in the specific case of planet detection and measurement with gaia

Suppose that you have an abstract for a scientific paper: a new measurement of the rare decay @xmath0 performed with the cmd-2 detector at novosibirsk is described . of the data sample corresponding to the integrated luminosity of 14.5 pb@xmath1 , twenty one events have been selected in the mode @xmath2 , @xmath3 . the following branching ratio was obtained : b(@xmath4 . . And you have already written the first three sentences of the full article: radiative decays of vector mesons have traditionally been a good laboratory for various tests of the quark model and su(3 ) symmetry @xcite . a recent discovery of the @xmath5 decay by the cmd-2 group @xcite has been the last link in the otherwise complete picture of radiative magnetic dipole transitions between light vector and pseudoscalar mesons . this observation was later confirmed by the snd group @xcite . both experiments suffered from a low number of observed events , resulting in large uncertainties in the determined branching ratio and making comparison to theory difficult . in this paper we report on the improved measurement of the rate of the @xmath5 decay based upon the total data sample accumulated with cmd-2 in the @xmath6-meson energy range .. Please generate the next two sentences of the article

it includes 3.1 pb@xmath1 of data collected in 1992 1996 in our first measurement which used only photons observed in the csi barrel calorimeter , and about 11.4 pb@xmath1 collected in 1997 1998 . in addition , this analysis uses photons detected in either the csi barrel or the bgo endcap calorimeters for both data samples providing better detection efficiency than before .

Suppose that you have an abstract for a scientific paper: global , population - wide oscillations in models of cyclic dominance may result in the collapse of biodiversity due to the accidental extinction of one species in the loop . previous research has shown that such oscillations can emerge if the interaction network has small - world properties , and more generally , because of long - range interactions among individuals or because of mobility . but although these features are all common in nature , global oscillations are rarely observed in actual biological systems . this begets the question what is the missing ingredient that would prevent local oscillations to synchronize across the population to form global oscillations . here we show that , although heterogeneous species - specific invasion rates fail to have a noticeable impact on species coexistence , randomness in site - specific invasion rates successfully hinders the emergence of global oscillations and thus preserves biodiversity . our model takes into account that the environment is often not uniform but rather spatially heterogeneous , which may influence the success of microscopic dynamics locally . this prevents the synchronization of locally emerging oscillations , and ultimately results in a phenomenon where one type of randomness is used to mitigate the adverse effects of other types of randomness in the system . . And you have already written the first three sentences of the full article: models of cyclic dominance are traditionally employed to study biodiversity in biologically inspired settings @xcite . the simplest such model is the rock - paper - scissors game @xcite , where rock crashes scissors , scissors cut paper , and paper wraps rock to close the loop of dominance . the game has no obvious winner and is very simple , yet still , it is an adequate model that captures the essence of many realistic biological systems .. Please generate the next two sentences of the article

examples include the mating strategy of side - blotched lizards @xcite , the overgrowth of marine sessile organisms @xcite , genetic regulation in the repressilator @xcite , parasitic plant on host plant communities @xcite , and competition in microbial populations @xcite . cyclical interactions may also emerge spontaneously in the public goods game with correlated reward and punishment @xcite , in the ultimatum game @xcite , and in evolutionary social dilemmas with jokers @xcite or coevolution @xcite .

Suppose that you have an abstract for a scientific paper: we discuss electron scattering in a one - dimensional delta barrier potential with either time - dependent coupling constant ( classical model ) or a coupling constant that is linear in a boson coordinate ( quantum model ) . we find an exact continued fraction solution and fano like resonances in the transmission coefficient . in the quantum model , energies for perfect transmission exist below the first sideband threshold . . And you have already written the first three sentences of the full article: simple models for the interaction between fermions and bosons continue to be fascinating , as often very non - trivial results can be obtained from even the most primitive hamiltonians . exactly solvable models for the interaction of photons or phonons with electrons in quantum dots @xcite or quasi - one - dimensional systems @xcite provide the best examples , as they often provide a deep insight into rich and complex physics . in this contribution , we re - consider a simple model for a single electron of mass @xmath0 in one dimension that interacts with a delta - barrier through a coupling parameter that itself is a dynamical quantity . the hamiltonian is written as @xmath1\right\}+\omega a^{\dagger}a.\end{aligned}\ ] ] here , @xmath2 creates a boson of frequency @xmath3 and @xmath4 $ ] is a dynamical contribution on top of the static coupling constant @xmath5 .. Please generate the next two sentences of the article

the constant zero point energy is omitted since it merely shifts the energy scale by @xmath6 . the lattice version of this model was originally introduced by gelfand , schmitt - rink and levi @xcite years ago in the study of tunneling in presence of phonons , and was shortly afterwards compared to a corresponding time - dependent classical hamiltonian @xcite , the continuous version of which reads @xmath7 @xmath8 is obtained as the interaction picture hamiltonian of eq.([hamiltonian ] ) with respect to @xmath9 , after replacing the boson operators by @xmath10 . in its time - dependent version , eq.([hamiltonianc ] ) has subsequently been used as a model for scattering in quasi - one - dimensional quantum wires by bagwell and co - workers @xcite , who found fano - type resonances in the transmission coefficient as a function of the energy of an incident electron .

Suppose that you have an abstract for a scientific paper: this paper studies infinite graphs produced from a natural unfolding operation applied to finite graphs . graphs produced via such operations are of finite degree and automatic over the unary alphabet ( that is , they can be described by finite automata over unary alphabet ) . we investigate algorithmic properties of such unfolded graphs given their finite presentations . in particular , we ask whether a given node belongs to an infinite component , whether two given nodes in the graph are reachable from one another , and whether the graph is connected . we give polynomial - time algorithms for each of these questions . for a fixed input graph , the algorithm for the first question is in constant time and the second question is decided using an automaton that recognizes reachability relation in a uniform way . hence , we improve on previous work , in which non - elementary or non - uniform algorithms were found . . And you have already written the first three sentences of the full article: we study the algorithmic properties of infinite graphs that result from a natural unfolding operation applied to finite graphs . the unfolding process always produces infinite graphs of finite degree . moreover , the class of resulting graphs is a subclass of the class of automatic graphs . as such. Please generate the next two sentences of the article

, any element of this class possesses all the known algorithmic and algebraic properties of automatic structures . an equivalent way to describe these graphs employs automata over a unary alphabet ( see theorem [ thm : gsigma ] ) .

Suppose that you have an abstract for a scientific paper: it is shown that the molecular ion @xmath0 does not exist in a form of the equilateral triangle . to this end , a compact variational method is presented which is based on a linear superposition of six specially tailored trial functions containing non - linear parameters . careful optimization of a total of fifteen parameters gives consistently lower variational results for the electronic energy than can be obtained with standard methods of quantum chemistry even with huge basis sets as large as mcc - pv7z . _ dedicated to professor rudolf zahradnik on the occasion of his 80th birthday _ . And you have already written the first three sentences of the full article: the trihydrogen dication , @xmath1 , which consists of three protons and one electron , is among the simplest coulomb systems . its stability has been studied intensely in the sixties and early seventies . in a series of articles , conroy @xcite investigated the potential energy surfaces of the electronic ground state and the lowest excited states at linear and isosceles triangular configurations . he employed a variational approach in which the electronic trial wavefunction is expanded around the center of the nuclear charges . analyzing the contour plots conroy concluded that @xmath1 is not stable .. Please generate the next two sentences of the article

schwartz and schaad @xcite , and somorjai and yue @xcite , who reported single - point calculations of the system @xmath2 at the supposed equilibrium equilateral triangular configuration of @xmath3 , did not address the stability problem . to assess conroy s results , berkowitz and stocker @xcite searched for this ion through charge stripping experiments on @xmath4 . they could not find evidence of stable @xmath1 .

Suppose that you have an abstract for a scientific paper: we study bidding and pricing competition between two spiteful mobile network operators ( mnos ) with considering their existing spectrum holdings . given asymmetric - valued spectrum blocks are auctioned off to them via a first - price sealed - bid auction , we investigate the interactions between two spiteful mnos and users as a three - stage dynamic game and characterize the dynamic game s equilibria . we show an asymmetric pricing structure and different market share between two spiteful mnos . perhaps counter - intuitively , our results show that the mno who acquires the less - valued spectrum block always lowers his service price despite providing double - speed lte service to users . we also show that the mno who acquires the high - valued spectrum block , despite charing a higher price , still achieves more market share than the other mno . we further show that the competition between two mnos leads to some loss of their revenues . by investigating a cross - over point at which the mnos profits are switched , it serves as the benchmark of practical auction designs . . And you have already written the first three sentences of the full article: due to the exploding popularity of all things wireless , the demand for wireless data traffic increases dramatically . according to a cisco report , global mobile data traffic will increase 13-fold between 2012 and 2017 @xcite . this dramatic demand puts on pressure on mobile network operators ( mnos ) to purchase more spectrum .. Please generate the next two sentences of the article

however , wireless spectrum is a scarce resource for mobile services . even if the continued innovations in technological progress relax this constraint as it provides more capacity and higher quality of service ( qos ) , the shortage of spectrum is still the bottleneck when the mobile telecommunications industry is moving toward wireless broadband services @xcite . to achieve a dominant position for future wireless services , thus , it is significant how new spectrum is allocated to mnos .

Suppose that you have an abstract for a scientific paper: we study channelization and slope destabilization driven by subsurface ( groundwater ) flow in a laboratory experiment . the pressure of the water entering the sandpile from below as well as the slope of the sandpile are varied . we present quantitative understanding of the three modes of sediment mobilization in this experiment : surface erosion , fluidization , and slumping . the onset of erosion is controlled not only by shear stresses caused by surfical flows , but also hydrodynamic stresses deriving from subsurface flows . these additional forces require modification of the critical shields criterion . whereas surface flows alone can mobilize surface grains only when the water flux exceeds a threshold , subsurface flows cause this threshold to vanish at slopes steeper than a critical angle substantially smaller than the maximum angle of stability . slopes above this critical angle are unstable to channelization by any amount of fluid reaching the surface . . And you have already written the first three sentences of the full article: unlike water , a layer of sand will not flow unless its surface is inclined beyond a characteristic angle , known as the maximum angle of stability @xcite . this simple fact translates into a host of threshold phenomena wherever granular material is found . many such phenomena play a crucial role in the erosion of earth s surface , and very likely manifest themselves in the richness of the patterns exhibited by drainage networks . depending on geological , hydrological , and climatological properties , erosion by water. Please generate the next two sentences of the article

is mainly driven either by overland flow or subsurface flow . the former case occurs when the shear stress imposed by a sheet flow exceeds a threshold @xcite .

Suppose that you have an abstract for a scientific paper: in this paper , a meteoric plasma is analyzed from a physical viewpoint , with particular emphasis on its interaction with radio waves . the attention is drawn to some macroscopic characteristics of a meteoric plasma and it is shown that the electron ion collision frequency is not negligible , as commonly thought . . And you have already written the first three sentences of the full article: when meteoroids enter the earth s atmosphere , they create long and narrow trails of ionized gas , which can scatter radio waves . the meteor radio echo theory finds its roots in studies of the ionosphere made toward the end of the twenties ( skellet @xcite ) . but only after the second world war , and the development of military radar , the correlation between radio echoes and meteor trails became clear ( hey & stewart @xcite ) . the first experiments explicitly devoted to meteor studies were carried out by pierce ( @xcite ) , who observed draconids during the night of 9 to 10 october 1946 .. Please generate the next two sentences of the article

the first theories on the interaction of radio waves with meteors were due to lovell & clegg ( @xcite ) , kaiser & closs ( @xcite ) , herlofson ( @xcite ) . thereafter , between 1950 and 1960 , a lot of efforts in this field were undertaken , but after 1960 the interest quickly decayed .

Suppose that you have an abstract for a scientific paper: the _ rhic _ facility at _ bnl _ will be operating soon , part of the year , as a polarized proton - proton collider . this will allow the undertaking of a vast spin physics programme , mainly by the two large detectors _ phenix _ and _ star_. we review some theoretical aspects of this research programme which will allow , firstly to improve our present knowledge on polarized quark , gluon and sea distributions in a nucleon , secondly to perform novel _ qcd _ spin tests and finally , perhaps , to uncover some new physics . . And you have already written the first three sentences of the full article: considerable progress have been made over the last ten years or so , in our understanding of the spin structure of the nucleon . this is essentially due to a better determination of the polarized structure functions @xmath0 , from polarized deep - inelastic - scattering ( _ dis _ ) on different targets ( hydrogen , deuterium , helium-3 ) . however these fixed polarized targets experiments @xcite , performed at _ cern _ , _ desy _ and _ slac _ , cover only a limited kinematic region , that is @xmath1 , with the corresponding average @xmath2 between @xmath3 and @xmath4 . in spite of the constant progress realized in the accuracy of the data , they can still be described , non uniquely , in terms of several sets of polarized parton distributions .. Please generate the next two sentences of the article

in particular , sea quark , antiquark and gluon distributions remain highly ambiguous . the restricted @xmath5 range accessible by the data makes also rather difficult , sensible tests of the @xmath5 evolution , predicted by recent higher order _ qcd _ calculations .

Suppose that you have an abstract for a scientific paper: propagation of extremely short electromagnetic pulses in a homogeneous doubly - resonant medium is considered in the framework of the total maxwell - duffing - lorentz model , where the duffing oscillators ( anharmonic oscillators with cubic nonlinearities ) represent the dielectric response of the medium , and the lorentz harmonic oscillators represent the magnetic response . the wave propagation is governed by the one - dimensional maxwell equations . it is shown that the model possesses a one - parameter family of traveling - wave solutions with the structure of single or multiple humps . solutions are parametrized by the velocity of propagation . the spectrum of possible velocities is shown to be continuous on a small interval at the lower end of the spectrum ; elsewhere the velocities form a discrete set . a correlation between the number of humps and the velocity is established . the traveling - wave solutions are found to be stable with respect to weak perturbations . numerical simulations demonstrate that the traveling - wave pulses collide in a nearly elastic fashion . . And you have already written the first three sentences of the full article: the recent demonstration of artificial materials ( metamaterials ) with the left oriented triplet of electric @xmath0 , magnetic @xmath1 and wave vector @xmath2 of electromagnetic field @xcite stimulated studies of nonlinear optical phenomena in such materials @xcite . nonlinear dynamics of extremely short optical pulses in left - handed materials was the subject of particular interest in several recent papers @xcite . the first experimental realization of the left - handed property based on the resonant response of the artificial material to both electric and magnetic fields was described in @xcite . to mention just one of the latest experimental achievements ,. Please generate the next two sentences of the article

valentine et al @xcite were able to observe the negative refractive index in the balk material in the _ optical _ range . a theoretical description of the electromagnetic wave interaction with such double resonance materials ( drm ) was considered in @xcite .

Suppose that you have an abstract for a scientific paper: we present a theory for the large suppression of the superfluid - density , @xmath0 , in bafe@xmath1(as@xmath2p@xmath3)@xmath1 in the vicinity of a putative spin - density wave quantum critical point at a p - doping , @xmath4 . we argue that the transition becomes weakly first - order in the vicinity of @xmath5 , and disorder induces puddles of superconducting and antiferromagnetic regions at short length - scales ; thus the system becomes an electronic micro - emulsion . we propose that frustrated josephson couplings between the superconducting grains suppress @xmath0 . in addition , the presence of ` normal ' quasiparticles at the interface of the frustrated josephson junctions will give rise to a highly non - trivial feature in the low - frequency response in a narrow vicinity around @xmath6 . we propose a number of experiments to test our theory . _ introduction.- _ an important focus of the study of high temperature superconductivity ( sc ) has been on the role of antiferromagnetism ( afm ) and its relation to sc @xcite . there is clear evidence across many different families of compounds that sc appears in close proximity to an afm phase @xcite ; these families include the iron - pnictides , the electron - doped cuprates and the heavy - fermion superconductors . moreover , the optimal transition temperature ( @xmath7 ) of the sc is often situated where the normal state afm quantum critical point ( qcp ) would have been located , in the absence of superconductivity . the experimental detection of the qcp is often challenging in the normal state , and more so in the superconducting state . recently , a number of measurements were reported in a member of the pnictide family , bafe@xmath1(as@xmath2p@xmath3)@xmath1 , as a function of the isovalent p - doping , @xmath8 . the experiments show a phase transition involving onset of spin - density wave ( sdw ) order in the normal state above @xmath7 , which extrapolates to a @xmath9 sdw qcp ( see @xcite and references therein ) . .... And you have already written the first three sentences of the full article: in this supplementary material , we compare the value of the penetration depth obtained from experiments @xcite with the prediction from homes law ; for the latter , we use a combination of the experimental data obtained from optical - conductivity and dc transport . for each value of the doping ( @xmath8 ) , we estimate the ( approximate ) dc resistivity ( @xmath80 ) by extrapolating the curves to @xmath9 , from the transport data in fig.1(b ) of ref.@xcite . we estimate the value of @xmath81 , where @xmath23 is the superconducting gap , from the data for optical conductivity in the superconducting state , as shown in fig .. Please generate the next two sentences of the article

3(b ) of ref . @xcite . since @xmath7 remains relatively unchanged as a function of @xmath8 in the vicinity of optimal doping , we assume @xmath82 to be independent of @xmath8 such that @xmath83@xmath84s@xmath85 . then , in the dirty limit , _ s = _ . in order to obtain the penetration depth

Suppose that you have an abstract for a scientific paper: we study the coupling of magneto - acoustic waves to alvn waves using 2.5d numerical simulations . in our experiment , a fast magnetoacoustic wave of a given frequency and wavenumber is generated below the surface . the magnetic field in the domain is assumed homogeneous and inclined . the efficiency of the conversion to alfvn waves near the layer of equal acoustic and alfven speeds is measured calculating their energy flux . the particular amplitude and phase relations between the oscillations of magnetic field and velocity help us to demonstrate that the waves produced after the transformation and reaching upper atmosphere are indeed alfvn waves . we find that the conversion from fast magneto - acoustic waves to alfvn waves is particularly important for the inclination @xmath0 and azimuth @xmath1 angles of the magnetic field between 55 and 65 degrees , with the maximum shifted to larger inclinations for lower frequency waves . the maximum alfvn flux transmitted to the upper atmosphere is about 23 times lower than the corresponding acoustic flux . conversion from fast - mode high-@xmath2 magneto - acoustic waves ( analog of @xmath3 modes ) to slow - mode waves in solar active regions is relatively well studied both from analytical theories and numerical simulations ( e.g. , @xcite ) , see @xcite for a review . in a two - dimensional situation , the transformation from fast to slow magnetoacoustic modes is demonstrated to be particularly strong for a narrow range of the magnetic field inclinations around 2030 degrees to the vertical . however , no generalized picture exists so far for conversion from magneto - acoustic to alfvn waves in a three - dimensional situation . studies of this conversion were initiated by cally & goossens @xcite , who found that the conversion is most efficient for preferred magnetic field inclinations between 30 and 40 degrees , and azimuth angles between 60 and 80 degrees , and that alfvnic fluxes transmitted to the upper atmosphere can exceed acoustic.... And you have already written the first three sentences of the full article: 12 url # 1#1urlprefix[2][]#2. Please generate the next two sentences of the article

Suppose that you have an abstract for a scientific paper: we analyze wave propagation in the vacuum of podolsky regularized electrodynamics . two kinds of waves were found in the theory : the traditional non - dispersive waves of maxwell electrodynamics , and a dispersive wave reminiscent of wave propagation in a collisionless plasma . charged particle concentration was determined , and found to be huge in this vacuum . we interpret the results in terms of vacuum polarization effects induced in an otherwise classical theory . . And you have already written the first three sentences of the full article: classical electrodynamics has been extremely successful for the past 150 years or more . however , whenever it dealt with point charged particles , the results were disappointing : a divergent electromagnetic energy , the infamous @xmath0 problem of the electromagnetic mass in the abraham lorentz theory , and the runaway solutions of the classical lorentz dirac equation of motion are all symptoms of a deeper maladie . in our view , there is no really satisfactory way to solve these issues entirely within the classical context .. Please generate the next two sentences of the article

all of these problems occur in a very small length scale , in which classical electrodynamics is not supposed to work properly . therefore , any solution to these problems will have to involve contributions from processes that take place in the quantum realm .

Suppose that you have an abstract for a scientific paper: we propose a general geometric growth model for pseudofractal scale - free web , which is controlled by two tunable parameters . we derive exactly the main characteristics of the networks : degree distribution , second moment of degree distribution , degree correlations , distribution of clustering coefficient , as well as the diameter , which are partially determined by the parameters . analytical results show that the resulting networks are disassortative and follow power - law degree distributions , with a more general degree exponent tuned from 2 to @xmath0 ; the clustering coefficient of each individual node is inversely proportional to its degree and the average clustering coefficient of all nodes approaches to a large nonzero value in the infinite network order ; the diameter grows logarithmically with the number of network nodes . all these reveal that the networks described by our model have small - world effect and scale - free topology . complex networks , scale - free networks , disordered systems , networks . And you have already written the first three sentences of the full article: since the pioneering papers by watts and strogatz on small - world networks @xcite and barabsi and albert on scale - free networks @xcite , complex networks , which describe many systems in nature and society , have become an area of tremendous recent interest @xcite . in the last few years , modeling real - life systems has attracted an exceptional amount of attention within the physics community . while a lot of models have been proposed , most of them are stochastic @xcite . however , because of their advantages , deterministic networks have also received much attention @xcite .. Please generate the next two sentences of the article

first , the method of generating deterministic networks makes it easier to gain a visual understanding of how networks are shaped , and how do different nodes relate to each other @xcite ; moreover , deterministic networks allow to compute analytically their properties : degree distribution , clustering coefficient , average path length , diameter , betweenness , modularity and adjacency matrix whose eigenvalue spectrum characterizes the topology @xcite . the first model for deterministic scale - free networks was proposed by barabsi _

Suppose that you have an abstract for a scientific paper: we investigate the relationship between the colors , luminosities , and environments of galaxies in the sloan digital sky survey spectroscopic sample , using environmental measurements on scales ranging from @xmath0 to @xmath1 @xmath2 mpc . we find : ( 1 ) that the relationship between color and environment persists even to the lowest luminosities we probe ( @xmath3 ) ; ( 2 ) at luminosities and colors for which the galaxy correlation function has a large amplitude , it also has a steep slope ; and ( 3 ) in regions of a given overdensity on small scales ( 1 @xmath2 mpc ) , the overdensity on large scales ( 6 @xmath2 mpc ) does not appear to relate to the recent star formation history of the galaxies . of these results , the last has the most immediate application to galaxy formation theory . in particular , it lends support to the notion that a galaxy s properties are related only to the mass of its host dark matter halo , and not to the larger scale environment . . And you have already written the first three sentences of the full article: recent investigations of the large scale distribution of galaxies in the sloan digital sky survey ( sdss ; @xcite ) have revealed a complex relationship between the properties of galaxies , ( such as color , luminosity , surface brightness , and concentration ) and their environments ( @xcite ) . these and other investigations using the sdss ( @xcite ) and the two - degree field galaxy redshift survey ( @xcite ) have found that galaxy clustering is a function both of star formation history and of luminosity . for low luminosity galaxies , clustering is a strong function of color , while for luminous galaxies clustering is a strong function of luminosity . for red galaxies , clustering is a non - monotonic function of luminosity , peaking at both high and low luminosities . although galaxy clustering correlates also with surface brightness and concentration , @xcite and @xcite show that galaxy environment is independent of these properties at fixed color and luminosity .. Please generate the next two sentences of the article

thus , color and luminosity measures of star formation history appear to have a more fundamental relationship with environment than do surface brightness and concentration measures of the distribution of stars within the galaxy . some of the investigations above have explored the scale dependence of these relationships .

Suppose that you have an abstract for a scientific paper: global magnetic field extrapolations are now revealing the huge complexity of the sun s corona , and in particular the structure of the boundary between open and closed magnetic flux . moreover , recent developments indicate that magnetic reconnection in the corona likely occurs in highly fragmented current layers , and that this typically leads to a dramatic increase in the topological complexity beyond that of the equilibrium field . in this paper we use static models to investigate the consequences of reconnection at the open - closed flux boundary ( interchange reconnection " ) in a fragmented current layer . we demonstrate that it leads to efficient mixing of magnetic flux ( and therefore plasma ) from open and closed field regions . this corresponds to an increase in the length and complexity of the open - closed boundary . thus , whenever reconnection occurs at a null point or separator of this open - closed boundary , the associated separatrix arc of the so - called _ s - web _ in the high corona becomes not a single line but a band of finite thickness within which the open - closed boundary is highly structured . this has significant implications for the acceleration of the slow solar wind , for which the interaction of open and closed field is thought to be important , and may also explain the coronal origins of certain solar energetic particles . the topological structures examined contain magnetic null points , separatrices and separators , and include a model for a pseudo - streamer . the potential for understanding both the large scale morphology and fine structure observed in flare ribbons associated with coronal nulls is also discussed . . And you have already written the first three sentences of the full article: it is well established that the magnetic field that permeates the solar corona has a highly complex structure . although it is very difficult to measure directly the magnetic field vector in the corona , this complexity can be inferred from observations of the line - of - sight magnetic field at the photosphere . with each new satellite mission that is launched , we observe photospheric magnetic flux concentrations on ever smaller scales ( that seem to exhibit a power - law distribution with size , * ? ? ?. Please generate the next two sentences of the article

magnetic field extrapolations based on these observed photospheric polarity distributions exhibit an often bewildering degree of complexity . understanding the evolution of such a complex magnetic field structure is a major challenge . in recent years , significant progress has been made in developing tools with which to characterise the coronal magnetic field .

Suppose that you have an abstract for a scientific paper: a numerical method is described for evaluating transverse spin correlations in the random phase approximation . quantum spin - fluctuation corrections to sublattice magnetization are evaluated for the antiferromagnetic ground state of the half - filled hubbard model in two and three dimensions in the whole @xmath0 range . extension to the case of defects in the af is also discussed for spin vacancies and low@xmath1 impurities . in the @xmath2 limit , the vacancy - induced enhancement in the spin fluctuation correction is obtained for the spin - vacancy problem in two dimensions , for vacancy concentration up to the percolation threshold . for low-@xmath3 impurities , the overall spin fluctuation correction is found to be strongly suppressed , although surprisingly spin fluctuations are locally enhanced at the low@xmath1 sites . 2 . And you have already written the first three sentences of the full article: transverse spin fluctuations are gapless , low - energy excitations in the broken - symmetry state of magnetic systems possessing continuous spin - rotational symmetry . therefore at low temperatures they play an important role in diverse macroscopic properties such as existence of long - range order , magnitude and temperature - dependence of the order parameter , nel temperature , spin correlations etc . specifically in the antiferromagnetic ( af ) ground state of the half - filled hubbard model transverse spin fluctuations are important both in two and three dimensions , where antiferromagnetic long - range order ( aflro ) exists at @xmath4 . in the strong - coupling limit @xmath5 , where spin fluctuations are strongest , they significantly reduce the zero - temperature af order parameter in two dimensions to nearly @xmath6 of the classical ( hf ) value.@xcite similarly the nel temperature in three dimensions is reduced to nearly @xmath7 of the mean - field result @xmath8 , for the equivalent @xmath9 quantum heisenberg antiferromagnet ( qhaf).@xcite recently there has also been interest in spin fluctuations due to defects , disorder and vacancies in the quantum antiferromagnet . in the random-@xmath3 model , where @xmath3 is set to zero on a fraction @xmath10 of sites , the lattice - averaged af order parameter appears to be enhanced for small @xmath10 , as seen in qmc calculations,@xcite presumably due to an overall suppression of quantum spin fluctuations . on the other hand spin fluctuations. Please generate the next two sentences of the article

are enhanced by strong disorder in the hubbard model with random on - site energies . in the strong disorder regime , overlap of the two hubbard bands leads to formation of essentially empty and doubly - occupied sites , which act like spin vacancies.@xcite the problem of spin vacancies in the quantum antiferromagnet is also relevant to the electron - doped materials like @xmath11 , where spin - dilution behavior is observed.@xcite while the problem of magnon energy renormalization due to spin vacancies has been addressed recently,@xcite these methods are limited to the low - concentration limit , and the vacancy - induced enhancement in transverse spin fluctuations has not been studied in the whole range of vacancy concentration . in this paper

Suppose that you have an abstract for a scientific paper: we show that there are simple one dimensional problems for which the mhd code , zeus , generates significant errors , whereas upwind conservative schemes perform very well on these problems . . And you have already written the first three sentences of the full article: zeus is a freely available mhd code that is widely used by the astrophysical community . although stone & norman ( 1992a , b ) give results for the sod problem ( sod 1978 ) and its mhd equivalent , the brio and wu problem ( brio & wu 1988 ) , zeus does not appear to have been tested on a wide range of riemann problems such as those described in e.g. dai & woodward ( 1994 ) , ryu & jones ( 1995 ) , falle , komissarov & joarder ( 1998)and balsara ( 1998 ) . since zeus is neither upwind for all characteristic fields nor conservative , we might expect it to perform significantly less well than upwind conservative codes ( e.g. brio & wu 1988 ; dai & woodward 1994 ; ryu & jones 1995 ; falle , komissarov & joarder 1998 ; balsara 1998 ; powell et al . as we shall see , this is indeed true in the sense that there are a number of simple problems for which the zeus solution contains significant errors that are absent in solutions calculated with an upwind conservative scheme .. Please generate the next two sentences of the article

figures 1 and 2 show that zeus generates rarefaction shocks for both pure gas rarefactions and fast magnetosonic rarefactions , whereas the upwind conservative scheme described in falle , komissarov & joarder ( 1998 ) gives quite satisfactory results . in both cases , the zeus solutions are sensitive to the inertial frame and the rarefaction shocks can be removed by a galilean transformation that increases the x velocity sufficiently .

Suppose that you have an abstract for a scientific paper: recently acquired evidence shows that extrasolar asteroids exhibit over a factor of 100 variation in the iron to aluminum abundance ratio . this large range likely is a consequence of igneous differentiation that resulted from heating produced by radioactive decay of @xmath0al with an abundance comparable to that in the solar system s protoplanetary disk at birth . if so , the conventional view that our solar system began with an unusually high amount of @xmath0al should be discarded . . And you have already written the first three sentences of the full article: concentrations of excess @xmath0 mg , the decay product of the short - lived radionuclide @xmath0al [ mean life = 1.03 myr @xcite ] , show that the solar system formed with @xmath1(@xmath0al)/@xmath1(@xmath2al ) = 5.2 @xmath3 10@xmath4 @xcite . although there is evidence that there may have been deviations from this canonical " ratio across the solar protoplanetary disk by as much as a factor of 2 @xcite , the overall concentration of @xmath0al in the solar disk was more than a factor of 10 greater than the current average value in the interstellar medium of 3.0 @xmath3 10@xmath5 @xcite . while some @xmath0al may have been produced within the early solar system , most of it was not @xcite ; there must have been a significant external source of this short - lived nuclide .. Please generate the next two sentences of the article

commonly , the natal @xmath0al is taken as a signature of a nearby supernova that may have triggered the collapse of the molecular cloud from which the sun formed @xcite . alternatively , winds from massive stars may have supplied the bulk of the @xmath0al @xcite .

Suppose that you have an abstract for a scientific paper: coupled , multi - field models of inflation can provide several attractive features unavailable in the case of a single inflaton field . these models have a rich dynamical structure resulting from the interaction of the fields and their associated fluctuations . we present a formalism to study the nonequilibrium dynamics of coupled scalar fields . this formalism solves the problem of renormalizing interacting models in a transparent way using dimensional regularization . the evolution is generated by a renormalized effective lagrangian which incorporates the dynamics of the mean fields and their associated fluctuations at one - loop order . we apply our method to two problems of physical interest : ( i ) a simple two - field model which exemplifies applications to reheating in inflation , and ( ii ) a supersymmetric hybrid inflation model . this second case is interesting because inflation terminates via a smooth phase transition which gives rise to a spinodal instability in one of the fields . we study the evolution of the zero mode of the fields and the energy density transfer to the fluctuations from the mean fields . we conclude that back reaction effects can be significant over a wide parameter range . in particular for the supersymmetric hybrid model we find that particle production can be suppressed due to these effects . . And you have already written the first three sentences of the full article: in recent years , the study of nonequilibrium dynamics in quantum field theory has received much attention in various areas of physics , and particularly in cosmology . the work has been driven largely by inflation @xcite , the most successful known mechanism for explaining the large - scale homogeneity and isotropy of the universe _ and _ the small - scale inhomogeneity and anisotropy of the universe @xcite . with observations for the first time able to directly test the more detailed predictions of specific inflationary models , the efforts in understanding inflation and its dynamics have redoubled . one area of particular interest is the dynamics of multi - field models of inflation in which the inflaton is coupled to another dynamical field during inflation .. Please generate the next two sentences of the article

these models can lead to a variety of features unavailable in the case of a single field . such multi - field scenarios include the well known hybrid inflation models @xcite . on top of the dynamics during inflation ,

Suppose that you have an abstract for a scientific paper: high - brightness electron beams with low energy spread at existing and future x - ray free - electron lasers are affected by various collective beam self - interactions and microbunching instabilities . the corresponding coherent optical radiation effects , e.g. , coherent optical transition radiation , impede electron beam profile imaging and become a serious issue for all kinds of electron beam diagnostics using imaging screens . furthermore , coherent optical radiation effects can also be related to intrinsically ultrashort electron bunches or the existence of ultrashort spikes inside the electron bunches . in this paper , we discuss methods to suppress coherent optical radiation effects both by electron beam profile imaging in dispersive beamlines and by using scintillation imaging screens in combination with separation techniques . the suppression of coherent optical emission in dispersive beamlines is shown by analytical calculations , numerical simulations , and measurements . transverse and longitudinal electron beam profile measurements in the presence of coherent optical radiation effects in non - dispersive beamlines are demonstrated by applying a temporal separation technique . . And you have already written the first three sentences of the full article: x - ray free - electron lasers ( fels ) offer a brilliant tool for science at atomic length and ultrafast time scales @xcite , and they have been realized with the operation of the free - electron laser in hamburg ( flash ) @xcite , the linac coherent light source ( lcls ) @xcite , and the spring-8 angstrom compact free electron laser ( sacla ) @xcite . the x - ray fel driving electron bunches are subject to several collective effects , e.g. , microbunching instabilities or coherent synchrotron radiation ( csr ) , which degrade the required high transverse and longitudinal beam brightness @xcite . these instabilities may not only result in significant deteriorations of the fel performance @xcite but also in coherent radiation effects @xcite such as coherent optical transition radiation ( cotr ) or csr in the optical wavelength range @xcite ( abbreviated as cosr ) .. Please generate the next two sentences of the article

beam profile imaging dominated by coherent optical radiation leads to an incorrect representation of the transverse charge distribution @xcite and renders electron beam diagnostics with standard imaging screens , e.g. , otr screens , and all the related diagnostics such as emittance or bunch length diagnostics impossible . however , beam diagnostics with imaging screens are essential for single - shot measurements or in cases where two transverse dimensions are required , e.g. , in slice - emittance or longitudinal phase space measurements @xcite . microbunching instabilities associated with longitudinal electron bunch compression can be mitigated by introducing additional uncorrelated energy spread @xcite as successfully demonstrated by the operation of the laser heater system at the lcls @xcite .

Suppose that you have an abstract for a scientific paper: we measure the angular power spectrum @xmath0 of radio galaxies in the nrao vla sky survey ( nvss ) using two independent methods : direct spherical harmonic analysis and maximum likelihood estimation . the results are consistent and can be understood using models for the spatial matter power spectrum and for the redshift distribution of radio galaxies at mjy flux - density levels . a good fit to the angular power spectrum can only be achieved if radio galaxies possess high bias with respect to mass fluctuations ; by marginalizing over the other parameters of the model we derive a @xmath1 confidence interval @xmath2 , where @xmath3 is the linear bias factor for radio galaxies and @xmath4 describes the normalization of the matter power spectrum . our models indicate that the majority of the signal in the nvss @xmath0 spectrum is generated at low redshifts @xmath5 . individual redshifts for the nvss sources are thus required to alleviate projection effects and probe directly the matter power spectrum on large scales . large - scale structure of universe galaxies : active surveys . And you have already written the first three sentences of the full article: active galactic nuclei ( agn ) mapped in radio waves are an interesting probe of large - scale structure . they can be routinely detected out to very large redshift ( @xmath6 ) over wide areas of the sky and hence delineate the largest structures and their evolution over cosmic epoch . radio emission is insensitive to dust obscuration and radio agn are effective tracers of mass : they are uniformly hosted by massive elliptical galaxies and have been shown to trace both clusters ( hill & lilly 1991 ) and superclusters ( brand et al .. Please generate the next two sentences of the article

2003 ) . the current generation of wide - area radio surveys such as faint images of the radio sky at twenty centimetres ( first ; becker , white & helfand 1995 ) and the nrao vla sky survey ( nvss ; condon et al . 1998 ) contain radio galaxies in very large numbers ( @xmath7 ) and have allowed accurate measurements of the imprint of radio galaxy angular clustering .

Suppose that you have an abstract for a scientific paper: we report the results of our _ chandra _ observations of six qsos at @xmath0 from the palomer transit grism survey . our primary goal is to investigate the possible systematic change of @xmath1 between @xmath2 and @xmath0 , between which a rapid rise of luminous qso number density with cosmic time is observed . the summed spectrum showed a power - law spectrum with photon index of @xmath3 , which is similar to other unabsorbed agns . combining our @xmath0 qsos with x - ray observations of qsos at @xmath2 from literaure / archive , we find a correlation of @xmath1 with optical luminosity . this is consistent with the fact that the luminosity function slope of the luminous end of the x - ray selected qsos is steeper than that of optically - selected qsos . we discuss an upper limit to the redshift dependence of @xmath1 using a monte - carlo simulation . within the current statistical errors including the derived limits on the redshift dependence of @xmath1 , we found that the behaviors of the x - ray and optically - selected qso number densities are consistent with each other . . And you have already written the first three sentences of the full article: large - scale optical surveys show that the luminous qso number density peaks at @xmath4 , before which ( in cosmic time ) the qso number density grows rapidly and after which the density steadily decays until the present epoch ( e.g. * ? ? ? * ; * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

the first indication of a density decline ( with redshift ) at @xmath5 was reported in the pioneering work of @xcite . the palomar transit grism survey ( ptgs ) @xcite was designed to investigate this possible redshift cutoff " , and produced a sample of 90 @xmath6 qsos ; an analysis of the ptgs @xcite ( hereafter ssg95 ) revealed a very rapid growth , by a factor of @xmath7 , of the number density of luminous qsos from @xmath8 to @xmath9 .

Suppose that you have an abstract for a scientific paper: we present a study of the inelastic decay rate of quasiparticles in a two - dimensional electron gas with spin - orbit interaction . the study is done within the @xmath0 approximation . the spin - orbit interaction is taken in the most general form that includes both rashba and dresselhaus contributions linear in magnitude of the electron 2d momentum . spin - orbit interaction effect on the inelastic decay rate is examined at different parameters characterizing the electron gas and the spin - orbit interaction strength in it . . And you have already written the first three sentences of the full article: nowadays , in condensed matter physics and semiconductor microelectronics , two - dimensional ( 2d ) electron system is one of the main objects of detailed study . such a system is formed by , e.g. , surface - state electrons or electrons in semiconductor heterostructures . phenomenon that is observed in such systems and makes them of great interest , especially in context of spintronic applications , is spin - orbit interaction ( soi ) . this interaction arise from the structure inversion asymmetry of potential confining the electron system in directions perpendicular to the confinement plane ( the rashba spin - orbit interaction@xcite ) and the bulk inversion asymmetry that is present in semiconductor heterostructures based on materials with a zinc - blende structure ( the dresselhaus spin - orbit interaction@xcite ) .. Please generate the next two sentences of the article

the dresselhaus interaction depends on semiconductor material and growth geometry , whereas the interaction strength of the rashba soi can be tuned via an externally applied electric field perpendicular to the confinement plane.@xcite as a result , one can controllably manipulate the spin in devices without recourse to an external magnetic field.@xcite . in order to efficiently exploit the mentioned phenomenon , a theoretical study of dynamics of electrons and holes in the 2d spin - orbit coupled electron systems is needed .

Suppose that you have an abstract for a scientific paper: the increasing scientific and technological interest in nanoparticles has raised the need for fast , efficient and precise characterization techniques . powder diffraction is a very efficient experimental method , as it is straightforward and non - destructive . however , its use for extracting information regarding very small particles brings some common crystallographic approximations to and beyond their limits of validity . powder pattern diffraction calculation methods are critically discussed , with special focus on spherical particles with log - normal distribution , with the target of determining size distribution parameters . a 20-nm ceo@xmath0 sample is analyzed as example . . And you have already written the first three sentences of the full article: we are assisting at a booming expansion of nanoparticle research and technology . synthesis method especially make fast progresses@xcite . analysis methods , however , are not up to speed . a fundamental simple task as determining and controlling. Please generate the next two sentences of the article

the size distribution of nanoparticles ( nps hereafter ) is currently a complex experimental work , involving electron microscopy and combined techniques . in this work we want to highlight the possibilities offered in this issue by a much less complex technique as powder diffraction .

Suppose that you have an abstract for a scientific paper: we extend the higgs triplet model so as to include dark matter candidates and a simple suppression mechanism for the vacuum expectation value ( @xmath0 ) of the triplet scalar field . the smallness of neutrino masses can be naturally explained with the suppressed value of @xmath0 even when the triplet fields are at the tev scale . the higgs sector is extended by introducing @xmath1-odd scalars ( an @xmath2 doublet @xmath3 and a real singlet @xmath4 ) in addition to a @xmath1-even complex singlet scalar @xmath5 whose vacuum expectation value violates the lepton number conservation by a unit . in our model , @xmath0 is generated by the one - loop diagram to which @xmath1-odd particles contribute . the lightest @xmath1-odd scalar boson can be a candidate for the dark matter . we briefly discuss a characteristic signal of our model at the lhc . . And you have already written the first three sentences of the full article: existence of dark matter ( dm ) has been established , and its thermal relic abundance has been determined by the wmap experiment @xcite . if the essence of dm is an elementary particle , the weakly interacting massive particle ( wimp ) would be a promising candidate . it is desired to have a viable candidate for the dark matter in models beyond the standard model ( sm ) . the wimp dark matter candidate can be accommodated economically by introducing only an inert scalar field @xcite , where we use `` inert '' for the @xmath1-odd property .. Please generate the next two sentences of the article

the imposed @xmath1 parity ensures the stability of the dm candidate . phenomenology in such models have been studied in , e.g. , refs .

Suppose that you have an abstract for a scientific paper: we present new observations of the cepa - east region of massive star formation and describe an extended and dynamically distinct feature not previously recognised . this feature is present in emission from h@xmath0cs , ocs , ch@xmath1oh , and hdo at 5.5 km s@xmath2 , but is not traced by conventional tracers of star forming regions h@xmath0s , so@xmath0 , so , cs . the feature is extended up to at least 0.1 pc . we show that the feature is neither a hot core nor a shocked outflow . however , the chemistry of the feature is consistent with predictions of a model of an eroding interface between a fast wind and a dense core ; mixing between the two media occurs in the interface on a timescale of 10 - 50 years . if these observations are confirmed by detailed maps and by detections in species also predicted to be abundant ( e.g. hco@xmath3 , h@xmath0co , and nh@xmath1 ) this feature would be the first detection of such an interface in regions of massive star formation . an important implication of the model is that a significant reservoir of sulfur in grain mantles is required to be in the form of ocs . . And you have already written the first three sentences of the full article: to explore the interactions of young stellar objects ( ysos ) with their environments , we recently carried out mm - wavelength molecular line observations towards star forming regions ( sfrs ) with well defined and bright high - velocity components . in particular , we mapped the well known cepheus a ( cepa ; * ? ? ? * and references therein ) sfr in several shock - chemistry tracers such as h@xmath0s , so@xmath0 , and hdo @xcite .. Please generate the next two sentences of the article

those results show that the group of b - type stars located in cepa - east producing a hot core @xcite , are also associated with multiple mass loss processes . in particular , beside the already known three flows pointing in the sw , ne , and se directions , a fourth outflow flowing towards the south has been detected thanks to the shock - chemistry tracers .

Suppose that you have an abstract for a scientific paper: a _ primitive hole _ of a graph @xmath0 is a cycle of length @xmath1 in @xmath0 . the number of primitive holes in a given graph @xmath0 is called the primitive hole number of that graph @xmath0 . the primitive degree of a vertex @xmath2 of a given graph @xmath0 is the number of primitive holes incident on the vertex @xmath2 . in this paper , we introduce the notion of set - graphs and study the properties and characteristics of set - graphs . we also check the primitive hole number and primitive degree of set - graphs . interesting introductory results on the nature of order of set - graphs , degree of the vertices corresponding to subsets of equal cardinality , the number of largest complete subgraphs in a set - graph etc . are discussed in this study . a recursive formula to determine the primitive hole number of a set - graph is also derived in this paper . * key words : * set - graphs , primitive hole , primitive degree . * ms classification * : 05c07 , 05c38 , 05c78 . . And you have already written the first three sentences of the full article: for general notations and concepts in graph theory , we refer to @xcite , @xcite and @xcite . all graphs mentioned in this paper are simple , connected undirected and finite , unless mentioned otherwise . a _ hole _ of a simple connected graph @xmath0 is a chordless cycle @xmath3 , where @xmath4 , in @xmath0 .. Please generate the next two sentences of the article

the _ girth _ of a simple connected graph @xmath0 , denoted by @xmath5 , is the order of the smallest cycle in @xmath0 . the following notions are introduced in @xcite .

Suppose that you have an abstract for a scientific paper: we investigate particle production in an expanding universe under the assumption that the lagrangian contains the einstein term @xmath0 plus a modified gravity term of the form @xmath1 , where @xmath2 is a constant . dark fluid is considered as the main content of the universe and the big rip singularity appears . quantum effects due to particle creation is analysed near the singularity and we find that for @xmath3\frac{1}{2 } , 1[$ ] , quantum effects are dominant and the big rip may be avoided whereas for @xmath4 the dark fluid is dominant and the singularity remains . the cardy - verlinde formula is also introduced and its equivalence with the total entropy of the universe is checked . it is found that this can always occur in einstein gravity while in f(r ) gravity , it holds only for @xmath5 , @xmath6 being the space dimension , corresponding to the situation in which the big rip can not be avoided . * quantum effects from particle production on background evolution and cardy - verlinde formula in f(r ) gravity + * m. j. s. houndjo , a . v. monwanouand jean b. chabi orou + pacs numbers : 04.50.kd , 98.80.cq , 02.40.xx , 05 . . And you have already written the first three sentences of the full article: general relativity ( gr ) is widely accepted as a fundamental theory to describe the geometric properties of spacetime @xcite . in an homogeneous and isotropic spacetime , the so - called friedmann - robertson - walker ( frw ) model , the einstein field equations give rise to the friedmann equations that describe the evolution of the universe . it describes the universe from around one second after the big bang to the present matter dominated era .. Please generate the next two sentences of the article

this standard model s success is in part due to several of its predictions having been verified by observation . for example , the abundances helium with respect to other light elements observed in the universe agrees well with the predictions of this model .

Suppose that you have an abstract for a scientific paper: in this paper , we study the response of 2d framed structures made of rectangular cells , to the sudden removal of columns . we employ a simulation algorithm based on the discrete element method , where the structural elements are represented by elasto - plastic euler bernoulli beams with elongation - rotation failure threshold . the effect of structural cell slenderness and of topological hierarchy on the dynamic residual strength after damage @xmath0 is investigated . topologically _ hierarchical _ frames have a primary structure made of few massive elements , while _ homogeneous _ frames are made of many thin elements . we also show how @xmath0 depends on the activated collapse mechanisms , which are determined by the mechanical hierarchy between beams and columns , i.e. by their relative strength and stiffness . finally , principles of robustness - oriented capacity design which seem to be in contrast to the conventional anti - seismic capacity design are addressed . * keywords : * frames , progressive collapse , robustness , hierarchy . And you have already written the first three sentences of the full article: since many decades , design codes ensure a very low probability that a building collapses under ordinary loads , like self weight , dead and live service load , or snow . nevertheless buildings still do collapse , from time to time . an extremely small fraction of collapses originates from unlikely combinations of intense ordinary load with very poor strength of the building .. Please generate the next two sentences of the article

the majority of structural collapses are due to accidental events that are not considered in standard design . examples of such events are : gross design or construction errors , irresponsible disregard of rules or design prescriptions , and several rare load scenarios like e.g. earthquakes , fire , floods , settlements , impacts , or explosions @xcite .

Suppose that you have an abstract for a scientific paper: we use the qcd sum rules to evaluate the mass of a possible scalar mesonic state that couples to a molecular @xmath0 current . we find a mass @xmath1 gev , which is in a excellent agreement with the recently observed @xmath2 charmonium state . we consider the contributions of condensates up to dimension eight , we work at leading order in @xmath3 and we keep terms which are linear in the strange quark mass @xmath4 . we also consider a molecular @xmath5 current and we obtain @xmath6 , around 200 mev above the mass of the @xmath7 charmonium state . we conclude that it is possible to describe the @xmath2 structure as a @xmath8 molecular state . there is growing evidence that at least some of the new charmonium states recently discovery in the b - factories are non conventional @xmath9 states . some possible interpretations for these states are mesonic molecules , tetraquarks , or / and hybrid mesons . some of these new mesons have their masses very close to the meson - meson threshold like the @xmath10 @xcite and the @xmath11 @xcite . therefore , a molecular interpretation for these states seems natural . the most recent aquisiton for this list of peculiar states is the narrow structure observed by the cdf collaboration in the decay @xmath12 . the mass and width of this structure is @xmath13 , @xmath14 @xcite . since the @xmath2 decays into two @xmath15 vector mesons , it has positive @xmath16 and @xmath17 parities . there are already some theoretical interpretations for this structure . its interpretation as a conventional @xmath9 state is complicated because , as pointed out by the cdf collaboration @xcite , it lies well above the threshold for open charm decays and , therefore , a @xmath9 state with this mass would decay predominantly into an open charm pair with a large total width . in ref . @xcite , the authors interpreted the @xmath2 as the molecular partner of the charmonium - like state @xmath7 , which was observed by belle and babar collaborations near the @xmath18.... And you have already written the first three sentences of the full article: we would like to thank f.s . navarra for fruitiful conversations . this work has been partly supported by fapesp and cnpq - brazil . for a review and references to original works ,. Please generate the next two sentences of the article

see e.g. , s. narison , _ qcd as a theory of hadrons , cambridge monogr . part . * 17 * , 1 ( 2002 ) [ hep - h/0205006 ] ; _ qcd spectral sum rules , world sci .

Suppose that you have an abstract for a scientific paper: conservative bsm models with rich scalar sector , such as multi - higgs - doublet models , can easily accommodate the sm - like properties of the 125 gev scalar observed at the lhc . possessing a variety of bsm signals , they are worth investigating in fuller detail . systematic study of these models is hampered by the highly multi - dimensional parameter space and by mathematical challenges . i outline some directions along which multi - higgs - doublet models in the vicinity of a large discrete symmetry can be systematically explored . . And you have already written the first three sentences of the full article: the lhc run 1 results , and especially the measured higgs boson properties @xcite , reveal a sm - like picture of the particle physics at the electroweak scale . nevertheless this situation is compatible with a potentially very rich scalar sector , hidden from direct inspection due to some decoupling or alignment arguments . assuming that this is the situation at the tev scale , one can ask what are the best experimental shortcuts to this hidden sector , and how one should probe it at colliders . of course , the answer strongly depends on the higgs sector chosen , and hundreds of papers have investigated it in various specific circumstances . also , the full parameter space is usually huge which renders it impossible to systematically explore the model in its full complexity , neither with algebra nor with numerical methods . in these cases ,. Please generate the next two sentences of the article

one usually resorts to specific models in particular corners of the parameter space . without any direct clue from experiment , one usually tries to uncover all physically interesting situations within a given model and to check which of them offer the most attractive description of the data . this undertaking requires a systematic exploration of the entire parameter space of a model , which for most cases is beyond the reach of traditional methods .

Suppose that you have an abstract for a scientific paper: a feedback mechanism that involves the proteins p53 and mdm2 , induces cell death as a controled response to severe dna damage . a minimal model for this mechanism demonstrates that the respone may be dynamic and connected with the time needed to translate the mdm2 protein . the response takes place if the dissociation constant @xmath0 between p53 and mdm2 varies from its normal value . although it is widely believed that it is an increase in @xmath0 that triggers the response , we show that the experimental behaviour is better described by a decrease in the dissociation constant . the response is quite robust upon changes in the parameters of the system , as required by any control mechanism , except for few weak points , which could be connected with the onset of cancer . pacs : 87.16.yc . And you have already written the first three sentences of the full article: in healthy cells , a loopback mechanism involving the protein p53 is believed to cause growth arrest and apoptosis as a response to dna damage @xcite . mutations in the sequence of p53 that potentially interfere with this mechanism have been observed to lead to the upraise of cancer @xcite . under normal conditions the amount of p53 protein in the cell is kept low by a genetic network built of the mdm2 gene , the mdm2 protein and the p53 protein itself .. Please generate the next two sentences of the article

p53 is produced at a essentially constant rate and promotes the expression of the mdm2 gene @xcite . on the other hand , the mdm2 protein binds to p53 and promotes its degradation @xcite , decreasing its concentration .

Suppose that you have an abstract for a scientific paper: target mass corrections to the twist-4 terms @xmath0 as well as to the leading - twist @xmath1 are discussed . pacs : 13.60.hb , 12.38.aw , 12.38cy ; 12.40.dh keywords : target mass corrections ; nachtmann moment ; higher - twist . + we know that different approaches [ 1 - 7 ] have been employed to study higher - twist effect to the nucleon structure functions . there were also several phenomenological analyses of the nucleon structure functions to study quark - hadron duality and to extract the higher - twist contributions ( like the ones of the twist-3 and twist-4 terms ) from experimental measurements [ 8 - 11 ] . those analyses are going to be more and more accurate since the more and more precise measurements of the nucleon spin structure functions @xmath2 and @xmath3 are becoming available [ 11 - 12 ] . the high precision data have been employed to study the validity of the quark - hadron duality for the nucleon structure function @xmath4 [ 13 ] and even for spin asymmetry @xmath5 by hermes [ 14 ] recently . several experiments to test the higher - twist effect on the nucleon spin structure functions are being carried out in the jefferson laboratory [ 9,15 ] . it has been pointed out , in the literature , that the target mass corrections ( tmcs ) should be considered in the studies of the nucleon structure functions [ 16 ] in a moderate @xmath6 region , and of the bloom - gilman quark - hadron duality [ 17 - 18 ] . therefore , only after the important target mass corrections are removed from the experimental data , one can reasonably extract the higher - twist effect [ 18 ] . there were several papers about the target mass corrections to @xmath7 and @xmath8 in the past [ 19 ] . recently , the target mass corrections to the nucleon structure functions for the polarized deep - inelastic scattering have been systematically studied [ 20 - 21 ] . in our previous work [ 22 ] , tmcs to the twist-3 matrix element in the nucleon structure functions are addressed . in this report.... And you have already written the first three sentences of the full article: this work is supported by the national sciences foundations of china under grant no . 10775148 , and by the cas knowledge innovation project kjcx3-syw - n2 . n. bianchi , a. fantoni , and s. liuti , phys .. Please generate the next two sentences of the article

rev . d*69 * , 014505 ( 2004 ) ; a. fantoni and s. liuti , hep - ph/0511278 ; m. osipenko et al . b*609 * , 259 ( 2005 ) ; m. osipenko et al .

Suppose that you have an abstract for a scientific paper: we investigate phase transitions in the ising model and the annni model in transverse field using the interface approach . the exact result of the ising chain in a transverse field is reproduced . we find that apart from the interfacial energy , there are two other response functions which show simple scaling behaviour . for the annni model in a transverse field , the phase diagram can be fully studied in the region where a ferromagnetic to paramagnetic phase transition occurs . the other region can be studied partially ; the boundary where the antiphase vanishes can be estimated . pacs nos . : 64.60.cn,75.10.jm,75.30.kz . And you have already written the first three sentences of the full article: phase transitions in ising spin systems driven entirely by quantum fluctuations have been getting a lot of attention recently [ 1 ] . the simplest of such systems is the ising model in a transverse field which can be exactly solved in one dimension . quantum fluctuations in ising systems with more complicated interactions which , for example , incorporate frustration and or disorder , give rise to novel and intriguing features . recently , the experimental realisation of some cases like the spin glass system in a transverse or tunnelling field , have added to the interest in such systems [ 1 ] .. Please generate the next two sentences of the article

we apply the method of interfaces [ 2 ] in the ising model and the anisotropic next nearest neighbour ising ( annni ) model [ 3 ] in a transverse field at zero temperature to study the quantum fluctuation driven transitions . in the process , we also explore the scope of the so called twist method [ 2,4 ] which we have shown to have additional features apart from the ones already known . recently , it has been shown in a variety of spin systems how the interfaces caused by twisting a system is closely linked to the phase transition . apart from the application of the twist method to several classical models like ising spins systems , potts model and spin glasses [ 2 ] ,

Suppose that you have an abstract for a scientific paper: this article presents a general multivariate @xmath0-sensitivity index , rooted in the @xmath0-divergence between the unconditional and conditional probability measures of a stochastic response , for global sensitivity analysis . unlike the variance - based sobol index , the @xmath0-sensitivity index is applicable to random input following dependent as well as independent probability distributions . since the class of @xmath0-divergences supports a wide variety of divergence or distance measures , a plethora of @xmath0-sensitivity indices are possible , affording diverse choices to sensitivity analysis . commonly used sensitivity indices or measures , such as mutual information , squared - loss mutual information , and borgonovo s importance measure , are shown to be special cases of the proposed sensitivity index . new theoretical results , revealing fundamental properties of the @xmath0-sensitivity index and establishing important inequalities , are presented . three new approximate methods , depending on how the probability densities of a stochastic response are determined , are proposed to estimate the sensitivity index . four numerical examples , including a computationally intensive stochastic boundary - value problem , illustrate these methods and explain when one method is more relevant than the others . borgonovo s importance measure , @xmath0-sensitivity index , kernel density estimation , mutual information , polynomial dimensional decomposition , squared - loss mutual information . . And you have already written the first three sentences of the full article: complex system modeling and simulation often mandate global sensitivity analysis , which constitutes the study of how the global variation of input , due to its uncertainty , influences the overall uncertain behavior of a response of interest . most common approaches to sensitivity analysis are firmly anchored in the second - moment properties the output variance which is divvied up , qualitatively or quantitatively , to distinct sources of input variation @xcite . there exist a multitude of methods or techniques for calculating the resultant sensitivity indices of a function of independent variables : the random balance design method @xcite , the state - dependent parameter metamodel @xcite , sobol s method @xcite , and the polynomial dimensional decomposition ( pdd ) method @xcite , to name but four .. Please generate the next two sentences of the article

a few methods , such as those presented by kucherenko , tarantola , and annoni @xcite and rahman @xcite , are also capable of sensitivity analysis entailing correlated or dependent input . implicit in the variance - driven global sensitivity analysis is the assumption that the statistical moments satisfactorily describe the stochastic response . in many applications

Suppose that you have an abstract for a scientific paper: quantum communication relies on optical implementations of channels , memories and repeaters . in the absence of perfect devices , a minimum requirement on real - world devices is that they preserve quantum correlations , meaning that they have some thoughput of a quantum mechanical nature . previous work has verified throughput in optical devices while using minimal resources . we extend this approach to the quantitative regime . our method is illustrated in a setting where the input consists of two coherent states while the output is measured by two homodyne measurement settings . . And you have already written the first three sentences of the full article: the introduction of new quantum mechanical technologies promises to fundamentally alter the way we communicate . quantum key distribution ( qkd ) , for instance , will allow us to communicate in an intrinsically secure way @xcite . but new quantum communication technologies will require a new telecommunications infrastructure , one which is quantum - enabled .. Please generate the next two sentences of the article

that is , this network must be able to properly accommodate the quantum properties that quantum communications inherently rely on . such a quantum network will contain many novel components , such as quantum memories @xcite , quantum repeaters @xcite , or , most generally , quantum channels .

Suppose that you have an abstract for a scientific paper: proteins are large and complex molecular machines . in order to perform their function , most of them need energy , _ e.g. _ either in the form of a photon , like in the case of the visual pigment rhodopsin , or through the breaking of a chemical bond , as in the presence of adenosine triphosphate ( atp ) . such energy , in turn , has to be transmitted to specific locations , often several tens of away from where it is initially released . here we show , within the framework of a coarse - grained nonlinear network model , that energy in a protein can jump from site to site with high yields , covering in many instances remarkably large distances . following single - site excitations , few specific sites are targeted , systematically within the stiffest regions . such energy transfers mark the spontaneous formation of a localized mode of nonlinear origin at the destination site , which acts as an efficient energy - accumulating centre . interestingly , yields are found to be optimum for excitation energies in the range of biologically relevant ones . , 0 mm protein dynamics is encoded in their structures and is often critical for their function @xcite . since the early eighties , it is well known that vibrational non - harmonicity has to be accounted for to understand intra - structure energy redistribution @xcite . among nonlinear effects , localized modes were suggested to play a key role @xcite , including topological excitations , such as solitons @xcite as well as discrete breathers ( db ) @xcite . the latter , also known as intrinsic localized modes ( ilms ) , are spatially localized , time - periodic vibrations found generically in many systems as a combined effect of nonlinearity and spatial discreteness @xcite . notably , dbs are able to _ harvest _ from the background and pin down for long times amounts of energy much larger than @xmath0 . indeed , their ability to pump energy from neighboring sites is a distinctive signature of db self - excitation @xcite.... And you have already written the first three sentences of the full article: recently , within the framework of a coarse - grained nonlinear network model ( nnm ) , we have shown that dbs in proteins feature strongly site - modulated properties @xcite . more precisely , we have shown that spatially localized band - edge normal modes ( nm ) can be continued from low energies to db solutions centered at the same sites as the corresponding nms ( the nm sites ) . note that the latters lie , as a rule , within the stiffest regions of a protein @xcite .. Please generate the next two sentences of the article

more generally , however , dbs display a gap in their excitation spectrum . as a consequence , they can `` jump '' to another site as their energy is varied , following spatial selection rules matching the pattern of dbs localized elsewhere @xcite . as a matter of fact , such jumps realize efficient _ energy transfers_. hereafter , we show that events of this kind , connecting with high yields even widely separated locations , can be triggered by a localized excitation , so long as its energy @xmath4 lies above a given threshold . energy transfer : all - site analysis .

Suppose that you have an abstract for a scientific paper: this paper presents a first study of the decay constants of the charged , or flavor - off - diagonal , pseudoscalar mesons to two loops for three flavors of sea quarks , in partially quenched chiral perturbation theory ( pq@xmath0pt ) . explicit analytical expressions up to @xmath1 in the momentum expansion are given . the calculations have been performed within the supersymmetric formulation of pq@xmath0pt . we also present some numerical results to indicate the size of the corrections . lu tp 05 - 1 + hep - lat/0501014 + january 2005 * decay constants of pseudoscalar mesons to two loops + in three - flavor partially quenched @xmath0pt * * johan bijnens and timo a. lhde * + department of theoretical physics , lund university , + slvegatan 14a , s 223 62 lund , sweden * abstract * : 12.38.gc , 12.39.fe , 11.30.rd . And you have already written the first three sentences of the full article: the derivation of low - energy hadronic observables , e.g. meson masses and decay constants , from the theory of the strong interaction ( qcd ) has so far proven to be impossible by means of analytical methods . because of this situation , numerical lattice qcd simulations , whereby the functional integral is evaluated numerically on a discretized space - time lattice , have developed into a major field of study . such simulations are , however , seriously hampered by difficulties in the simulation of dynamical sea quark effects .. Please generate the next two sentences of the article

although much progress has been made recently , it is still impractical , for computational reasons , to simulate with sea quark masses that are close to the physical @xmath2 quark masses of a few mev . this situation , with sea quark masses of a few tens of mev , is referred to as partially quenched ( pq ) qcd . consequently , the physical values of the sea quark masses have to be reached by extrapolation from the partially quenched simulation results .

Suppose that you have an abstract for a scientific paper: hypersensitivity to perturbation is a criterion for chaos based on the question of how much information about a perturbing environment is needed to keep the entropy of a hamiltonian system from increasing . in this paper we give a brief overview of our work on hypersensitivity to perturbation in classical and quantum systems . # . And you have already written the first three sentences of the full article: in both classical and quantum physics isolated systems can display unpredictable behavior , but the reasons for the unpredictability are quite different . in classical ( hamiltonian ) mechanics unpredictability is a consequence of chaotic dynamics , or exponential sensitivity to initial conditions , which makes it impossible to predict the phase - space trajectory of a system to a certain accuracy from initial data given to the same accuracy . this unpredictability , which comes from not knowing the system s initial conditions precisely , is measured by the kolmogorov - sinai ( ks ) entropy , which is the rate at which initial data must be supplied in order to continue predicting the coarse - grained phase - space trajectory @xcite . in quantum mechanics. Please generate the next two sentences of the article

there is no sensitivity to initial conditions in predicting the evolution of a state vector , because the unitary evolution of quantum mechanics preserves the inner product between state vectors . the absence of sensitivity to initial conditions seems to suggest that there is no quantum chaos . yet

Suppose that you have an abstract for a scientific paper: large volumes of ccd imaging data that will become available from wide - field cameras at telescopes such as the cfht , subaru , vst , or vista in the near future are highly suitable for systematic _ distance surveys of early - type galaxies _ using the surface brightness fluctuation ( sbf ) method . for the efficient processing of such large data sets , we are developing the first semi - automatic sbf analysis pipeline named sapac . after a brief description of the sbf method we discuss the image quality needed for a successful distance measurement and give some background information on sapac . . And you have already written the first three sentences of the full article: employing the surface brightness fluctuation signal of unresolved stars in distant galaxies is an effective and inexpensive new way to measure accurate distances to early - type ( dwarf ) galaxies . unlike other extragalactic distance indicators ( e.g. trgb , rr lyrae stars ) , this method does _ not _ require resolved stars therefore allowing distance measurements for early - type galaxies far beyond the practical limits of any of the classical distance indicators ( @xmath05mpc ) . with fourier analysis techniques , the sbf method quantifies the mean stellar flux per ccd pixel and rms variation due to poisson noise across a designated area in a dwarf galaxy . initially the sbf method was almost exclusively applied on nearby giant ellipticals and mw globular clusters ( e.g. tonry et al .. Please generate the next two sentences of the article

1989 , 1994 ) but was found to work equally well with dwarf elliptical ( de ) galaxies ( e.g. jerjen et al . 1998 , 2000 , 2001 , 2004 , and rekola et al . 2005 ) . as de galaxies are by far the most numerous galaxy type at the current cosmological epoch , the sbf method in combination with wide - field ccd imaging offers the opportunity for the first time to spatially locate des in vast numbers and thereby to map in 3d the densest environments of the local universe ( for first results see contributions by ct et al . ,

Suppose that you have an abstract for a scientific paper: the bcs - bec crossover is studied in a systematic way in the broken - symmetry phase between zero temperature and the critical temperature . this study bridges two regimes where quantum and thermal fluctuations are , respectively , important . the theory is implemented on physical grounds , by adopting a fermionic self - energy in the broken - symmetry phase that represents fermions coupled to superconducting fluctuations in weak coupling and to bosons described by the bogoliubov theory in strong coupling . this extension of the theory beyond mean field proves important at finite temperature , to connect with the results in the normal phase . the order parameter , the chemical potential , and the single - particle spectral function are calculated numerically for a wide range of coupling and temperature . this enables us to assess the quantitative importance of superconducting fluctuations in the broken - symmetry phase over the whole bcs - bec crossover . our results are relevant to the possible realizations of this crossover with high - temperature cuprate superconductors and with ultracold fermionic atoms in a trap . . And you have already written the first three sentences of the full article: in the bcs to bose - einstein condensation ( bec ) crossover @xcite , largely overlapping cooper pairs smoothly evolve into non - overlapping composite bosons as the fermionic attraction is progressively increased . these two physical situations ( cooper pairs vs composite bosons ) correspond to the weak- and strong - coupling limits of the theory , while in the interesting intermediate - coupling regime neither the fermionic nor the bosonic properties are fully realized . under these circumstances , the theory is fully controlled on the weak- and strong - coupling sides , while at intermediate coupling an interpolation scheme results ( as for all crossover approaches ) .. Please generate the next two sentences of the article

these physical ideas are implemented , in practice , by allowing for a strong decrease of the chemical potential _ at a given temperature _ when passing from the weak- to the strong - coupling limit . the bcs - bec crossover can be considered both below ( broken - symmetry phase ) and above ( normal phase ) the superconducting critical temperature . in particular , in the normal phase preformed pairs exist in the strong - coupling limit up to a temperature @xmath0 corresponding to the breaking of the pairs , while coherence among the pairs is established when the temperature is lowered below the superconducting critical temperature @xmath1 . this framework could be relevant to the evolution of the properties of high - temperature cuprate superconductors from the overdoped ( weak - coupling ) to the underdoped ( strong - coupling ) regions of their phase diagram @xcite .

Suppose that you have an abstract for a scientific paper: from the famous experiments of stern and gerlach to the present , measurements of magnetic dipole moments , and searches for electric dipole moments of `` elementary '' particles have played a major role in our understanding of sub - atomic physics . in this talk i discuss the progress on measurements and theory of the magnetic dipole moment of the muon . i also discuss a new proposal to search for a permanent electric dipole moment ( edm ) of the muon and put it into the more general context of other edm searches . these experiments , along with searches for the lepton flavor violating decays @xmath0 and @xmath1 , provide a path to the high - energy frontier through precision measurements . . And you have already written the first three sentences of the full article: over the past 83 years , the study of dipole moments of elementary particles has provided a wealth of information on subatomic physics . from the pioneering work of stern@xcite through the discovery of the large anomalous magnetic moments of the proton@xcite and neutron@xcite , the ground work was laid for the discovery of spin , of radiative corrections and the renormalizable theory of qed , of the quark structure of baryons and the development of qcd . a charged particle with spin @xmath2 has a magnetic moment @xmath3 where @xmath4 is the gyromagnetic ratio , @xmath5 is the anomaly , and the latter expression is what one finds in the particle data tables.@xcite the dirac equation tells us that for spin one - half point - like particles , @xmath6 for spin angular momentum , and is unity for orbital angular momentum ( the latter having been verified experimentally@xcite ) . for point particles ,. Please generate the next two sentences of the article

the anomaly arises from radiative corrections , two examples of which are shown in fig . [ fg : aexpan ] .

Suppose that you have an abstract for a scientific paper: we apply the global mode analysis , which has been recently developed for the modeling of khz quasi - periodic oscillations ( qpos ) from neutron stars , to the inner region of an accretion disk around a rotating black hole . within a pseudo - newtonian approach that keeps the ratio of the radial epicyclic frequency @xmath0 to the orbital frequency @xmath1 the same as the corresponding ratio for a kerr black hole we determine the innermost disk region where the hydrodynamic modes grow in amplitude . we find that the radiation flux emerging from the inner disk has the highest values within the same region . using the flux weighted averages of the frequency bands over this region we identify the growing modes with highest frequency branches @xmath2 and @xmath3 to be the plausible candidates for the high - frequency qpo pairs observed in black hole systems . the observed frequency ratio around @xmath4 can therefore be understood naturally in terms of the global free oscillations in the innermost region of a viscous accretion disk around a black hole without invoking a particular resonance to produce black hole qpos . although the frequency ratio @xmath5/@xmath6 is found to be not sensitive to the black hole s spin which is good for explaining the high - frequency qpos it may work as a limited diagnostic of the spin parameter to distinguish black holes with very large spin from the slowly rotating ones . within our model we estimate the frequency ratio of a high - frequency qpo pair to be greater than @xmath4 if the black hole is a slow rotator . for fast rotating black holes , we expect the same ratio to be less than @xmath4 . . And you have already written the first three sentences of the full article: the high energy emission from neutron stars and black holes in x - ray binaries is generally powered by accretion onto the compact object . the variability of x - ray light curve with different time scales from milliseconds to days is usually attributed to various characteristic time scales associated with accretion flow around the black hole or neutron star . in low - mass x - ray binaries ( lmxbs ) , where the central object is fed by an accretion disk , a few variability frequencies observed as quasi - periodic oscillation ( qpo ) peaks in addition to other broad - band features in the power spectra are common to both black hole and neutron star sources . although there are some phenomenological differences between qpos in black hole candidates and those observed in neutron star lmxbs , the similarities such as tight correlations of high and low frequency power spectral features in black hole and neutron star sources are remarkable ( van der klis 1994 ; psaltis , belloni , & van der klis 1999 ; wijnands & van der klis 1999 ) . any interpretation or model solely based on the existence of a magnetic field , a hard surface , which are neutron star like properties , or an innermost stable circular orbit ( isco ) as a black hole like property to produce qpos can not account for the correlations of timing properties among different sources .. Please generate the next two sentences of the article

qpos were discovered in the x - ray power density spectrum of black hole transients with frequencies in the @xmath7 hz range during the very high spectral state of these sources ( motch et al . 1983 ; miyamoto & kitamoto 1989 ; miyamoto et al . 1991 ; morgan , remillard , & greiner 1997 ; wijnands , homan , & van der klis 1999 ; sobczak et al .

Suppose that you have an abstract for a scientific paper: we show that new families of accelerating and almost nondiffracting beams ( solutions ) for maxwell s equations can be constructed . these are complex geometrical optics ( cgo ) solutions to maxwell s equations with nonlinear limiting carleman weights . they have the form of wave packets that propagate along circular trajectories while almost preserving a transverse intensity profile . we also show similar waves constructed using the approach combining cgo solutions and the kelvin transform . . And you have already written the first three sentences of the full article: the research on nondiffracting accelerating optical beams has attracted considerable attention since the first study and observation of such beams reported in 2007 @xcite . these are optical wave packets that propagate along a curved trajectory while preserving its transverse amplitude structure . the first of such beams , known as the airy beam , traces back to the context of quantum mechanics @xcite , as a solution to the free - potential schrdinger equation . in optics @xcite ,. Please generate the next two sentences of the article

the airy beam is understood as a solution to the paraxial wave equation , which is a good approximation of the propagation dynamics when the beam trajectory is limited to small ( paraxial ) angles @xmath0 . in this case , the airy beam propagates along a parabolic trajectory while maintaining its intensity profile . the desirable feature of simultaneous shape - preserving and self - bending has invoked many intriguing applications including inducing curved plasma filaments @xcite , synthesizing versatile bullets of light @xcite , carrying out autofocusing and supercontinuum experiments @xcite , manipulating microparticles @xcite and so on . however the spatial acceleration of a beam will make the bending angle continue increasing , eventually , the wave packet falls off into the non - paraxial regime and no longer nondiffracting . in @xcite , the authors found solutions to the maxwell s equations in free space , that propagate along semicircular trajectories without losing the intensity of their main lobes after a large angle ( @xmath1 ) bending . roughly speaking , in the two dimensional transverse electric ( te ) or transverse magnetic ( tm ) polarized cases , they examine the spherical harmonic expansion for the solution to the helmholtz equation , splitting the integral for the bessel function into two parts corresponding to both forward and backward propagations .

Suppose that you have an abstract for a scientific paper: we study the generation of small neutrino masses in an extra - dimensional model , where singlet fermions are allowed to propagate in the extra dimension , while the standard model particles are confined to a brane . motivated by the fact that extra - dimensional models are non - renormalizable , we truncate the kaluza klein towers at a maximal kaluza klein number . this truncation , together with the structure of the bulk majorana mass term , motivated by the sherk schwarz mechanism , implies that the kaluza klein modes of the singlet fermions pair to form dirac fermions , except for a number of unpaired majorana fermions at the top of each tower . these heavy majorana fermions are the only sources of lepton number breaking in the model , and similarly to the type - i seesaw mechanism , they naturally generate small masses for the left - handed neutrinos . the lower kaluza klein modes mix with the light neutrinos , and the mixing effects are not suppressed with respect to the light - neutrino masses . compared to conventional fermionic seesaw models , such mixing can be more significant . we study the signals of this model at the large hadron collider , and find that the current low - energy bounds on the non - unitarity of the leptonic mixing matrix are strong enough to exclude an observation . . And you have already written the first three sentences of the full article: experimental studies of neutrino oscillations have provided us with compelling evidence that neutrinos have masses and lepton flavors mix . among various theoretical models , the famous seesaw mechanism @xcite provides us with a very natural description of why the masses of the three known neutrinos are so small compared to the masses of the other standard model ( sm ) fermions . in the simplest type - i seesaw model , heavy right - handed neutrinos with a mass scale @xmath0 are introduced in addition to the sm particle content . in order to stabilize the masses of the light neutrinos around the sub - ev scale ,. Please generate the next two sentences of the article

@xmath1 is naturally expected , if the dirac mass @xmath2 between the left- and right - handed neutrinos is comparable with the mass of the top quark . the testability of conventional seesaw models is therefore questionable .

Suppose that you have an abstract for a scientific paper: the study of phase structure of dilute @xmath0he - @xmath1he solid mixture of different quality is performed by spin echo nmr technique . the diffusion coefficient is determined for each coexistent phase . two diffusion processes are observed in rapidly quenched ( non - equilibrium ) hcp samples : the first process has a diffusion coefficient corresponding to hcp phase , the second one has huge diffusion coefficient corresponding to liquid phase . that is evidence of liquid - like inclusions formation during fast crystal growing . it is established that these inclusions disappear in equilibrium crystals after careful annealing . pacs numbers : 61.72.cc , 66.30.ma , 61.50.-f , 64.70.d- keywords : nmr , @xmath0he-@xmath1he solid mixture , diffusion , defects * * + _ ye.o . vekhov , a.p . birchenko , n.p . mikhin , and e.ya . rudavskii _ + _ _ . And you have already written the first three sentences of the full article: last time the interest has sharply increased for searching the conditions for realization supersolidity phenomenon in solid @xmath1he @xcite , when the crystalline order combines with superfluidity . in spite of the great number of experimental and theoretical investigations in this area , the consensus has not been attained yet . for the present , it has been determined well that observing effects strongly depend on the growing conditions and annealing degree of helium crystals . the special modeling which was conducted from the first principles by monte - carlo method , showed that in the perfect hcp @xmath1he crystal the supersolidity effects can not appear @xcite . the most authors connect such effects in solid @xmath1he at low temperatures with the disorder in helium samples .. Please generate the next two sentences of the article

possible kinds of the disorder may be the defects , grain boundaries @xcite , glass phase , or liquid inclusions @xcite . also , the possible interpretation @xcite of the experiments on flow the superfluid helium through the solid helium @xcite show the essential role of the liquid channels , which may exist in the solid helium up to the ultralow temperatures . in this connection , the experiments which allow to identify the kind of the disorder , for example , in rapidly grown helium crystals , interesting .

Suppose that you have an abstract for a scientific paper: the creation of brane universes induced by a totally antisymmetric tensor living in a fixed background spacetime is presented , where a term involving the intrinsic curvature of the brane is considered . a canonical quantum mechanical approach employing wheeler - dewitt equation is done . the probability nucleation for the brane is calculated taking into account both an instanton method and a wkb approximation . some cosmological implications arose from the model are presented . . And you have already written the first three sentences of the full article: nowadays , with the standard cosmology the famous fundamental question , where did it all come from ? " still it does not have a convincing answer , reason why a new description is necessary . cosmologists during long time have believed that quantum cosmology can shed light on this question @xcite but some issues are in controversy , e.g. the lack of an intrinsic time variable in the theory @xcite , the validity of the minisuperspace approximation , the problem of cosmological boundary conditions @xcite , to mention something . among the proposals trying to outline a possible answer to the fundamental question , the so - called brane world scenaries ( bws ) @xcite became a promising way to understand the birth and then the evolution of our universe . grounded on the proposal that our universe can be thought as a 4-dimensional spacetime object embedded in an n - dimensional spacetime , the main physical idea behind of bws is that the matter fields are confined to a 3-dimensional space ( brane ) while the gravitational fields can extend into a higher - dimensional space ( bulk ) , where the graviton can travel into the extra dimensions .. Please generate the next two sentences of the article

originally proposed to resolve the hierarchy problem , bws has been applied to a great diversity of situations such as dark matter / energy , quientessence , cosmology , inflation and particle physics . on other hand , at the formal mathematical level , related applications of embedding theory such as generation of internal symmetries , quantum gravity and alternative kaluza - klein theories have been exploited @xcite . in the cosmology context there are predictions of these ideas , that could be tested by astronomical observations what constitutes one of the several reasons for which it is so attractive , so that it has predictive power @xcite . in these brane

Suppose that you have an abstract for a scientific paper: this note reports the results of a study of the accuracy in the determination of chargino and neutralino masses in two high - mass supersymmetric scenarios through kinematic endpoints and threshold scans at a multi - tev @xmath0 collider . the effects of initial state radiation , beamstrahlung and parton energy resolution are studied in fully hadronic final states of inclusive susy samples . results obtained at generator level are compared to those from fully simulated and reconstructed events for selected channels . . And you have already written the first three sentences of the full article: the study of the gaugino sector of supersymmetry is a complex and important endeavour , which appears well suited to a linear collider of sufficient energy and luminosity . the main observables of interest are the masses of the @xmath1 and @xmath2 states and their production cross sections , including those with polarised beams . @xmath3 collisions offer two independent techniques for determining the mass of supersymmetric particles .. Please generate the next two sentences of the article

these are the analysis of the energy spectrum of the sm particle produced in association with a lighter supersymmetric state in the two - body decays and the study of the pair production cross section near threshold . these techniques have already been extensively studied for lower centre - of - mass energies , @xmath4 , between 0.35 to 0.5 tev @xcite . in this note , we analyse the gaugino pair production and derive the statistical accuracy on their masses using both techniques and including the effects of initial state radiation ( isr ) , beamstrahlung ( bs ) and parton energy resolution for multi - tev @xmath3 collisions .

Suppose that you have an abstract for a scientific paper: low energy proton capture reactions in the mass 55 - 60 region are studied in a microscopic optical model . nuclear density profile is calculated using the relativistic mean field theory . the ddm3y interaction is folded with the theoretical density to obtain the proton - nucleus optical potential . a definite set of normalization parameters has been obtained for the concerned mass region by comparing with all available experimental data in this mass region . these parameters have been used to obtain proton capture rates for astrophysically important reactions in this mass region . . And you have already written the first three sentences of the full article: the study of the role of individual nuclear reactions in stellar evolution has been an important field of research in the last few decades . as a star evolves with time it passes through burning in different ranges of nuclear mass . at the same time , different nuclear processes become important at different time periods of evolution . a comprehensive study of these processes sheds light on various astrophysical phenomena . there are certain astrophysical sites which are responsible for the production of heavier nuclei beyond iron through the rapid capture of protons on seed nuclides . in the mass region of our interest. Please generate the next two sentences of the article

there are certain proton rich naturally occurring nuclei , which are not produced by the @xmath0-process or the @xmath1-process . these are called @xmath2-nuclei .

Suppose that you have an abstract for a scientific paper: we study the optomechanical design introduced by m. li _ et al . _ [ phys . rev . lett . * 103 * , 223901 ( 2009 ) ] , which is very effective for investigations of the effects of reactive coupling . we show the normal mode splitting that is due solely to reactive coupling rather than due to dispersive coupling . we suggest feeding the waveguide with a pump field along with a probe field and scanning the output probe for evidence of reactive - coupling - induced normal mode splitting . . And you have already written the first three sentences of the full article: in a recent paper li _ et al . _ @xcite presented a new design for an optomechanical system that consists of a microdisk resonator coupled to a waveguide . this design has several attractive features .. Please generate the next two sentences of the article

besides its universality , it enables one to study the reactive effects @xcite in optomechanical coupling . the origin of the reactive coupling is well explained in ref .

Suppose that you have an abstract for a scientific paper: the vlt on cerro paranal was used to observe four fields located at @xmath0 from the center of the galactic globular cluster ngc6712 in the v and r bands . the resulting color - magnitude diagram shows a well defined main sequence reaching down to the @xmath1 detection limit at @xmath2 , @xmath3 or approximately 4 magnitudes below the main sequence turn - off , the deepest obtained so far on this cluster . this yields a main sequence luminosity function that peaks at @xmath4 and drops down to the 50% completeness limit at @xmath5 . transformation to a mass function via the latest mass - luminosity relation appropriate to this object indicates that the peak of the luminosity function corresponds to @xmath6m@xmath7 , a value significantly higher than the @xmath8m@xmath7 , measured for most other clusters observed so far . since this object , in its galactic orbit , penetrates very deeply into the galactic bulge with perigalactic distance of @xmath9kpc , this result is the first strong evidence that tidal forces have stripped this cluster of a substantial portion of its lower mass star population all the way down to its half - light radius and possibly beyond . . And you have already written the first three sentences of the full article: ngc6712 is a small ( tidal radius @xmath10 ) and relatively loose ( @xmath11 ) and faint ( @xmath12 ; djorgovski @xcite ) galactic globular cluster ( gc ) that has not yet received much observational attention . its main claim to fame so far is due to the presence in its core of the high luminosity x - ray burster x1850086 whose optical counterpart may be a faint uv - excess object ( anderson et al . this fact presents somewhat of a puzzle since one would expect such an x - ray source to be located in a highly concentrated cluster where the stellar density favors its formation via tidal capture of a neutron star ( hertz & grindlay @xcite ) .. Please generate the next two sentences of the article

most other sources of this type have indeed been found in high density core collapse clusters suggesting that , perhaps , ngc6712 has already undergone such an event in the past and is now in a state of re - expansion ( grindlay et al . @xcite ) .

Suppose that you have an abstract for a scientific paper: in quantum information processing by nmr one of the major challenges is relaxation or decoherence . often it is found that the equilibrium mixed state of a spin system is not suitable as an initial state for computation and a definite initial state is required to be prepared prior to the computation . as these preferred initial states are non - equilibrium states , they are not stationary and are destroyed with time as the spin system relaxes toward its equilibrium , introducing error in computation . since it is not possible to cut off the relaxation processes completely , attempts are going on to develop alternate strategies like quantum error correction codes or noiseless subsystems . here we study the relaxation behavior of various pseudo pure states and analyze the role of cross terms between different relaxation processes , known as cross - correlation . it is found that while cross - correlations accelerate the relaxation of certain pseudo pure states , they retard that of others . . And you have already written the first three sentences of the full article: quantum information processing ( qip ) often requires pure state as the initial state @xcite . shor s prime factorizing algorithm @xcite , grover search algorithm @xcite are few examples . creation of pure state in nmr is not easy due to small gaps between nuclear magnetic energy levels and demands unrealistic experimental conditions like near absolute zero temperature or extremely high magnetic field .. Please generate the next two sentences of the article

this problem has been circumvented by creating a pseudo pure state ( pps ) . while in a pure state all energy levels except one have zero populations , in a pps all levels except one have equal populations . since the uniform background populations do not contribute to the nmr signal , such a state then mimics a pure state .

Suppose that you have an abstract for a scientific paper: the discovery of the microquasar ls 5039 well within the 95% conficence contour of the unidentified egret source ( ues ) 3eg j1824@xmath01514 was a major step towards the possible association between microquasars ( mqs ) and uess . the recent discovery of precessing relativistic radio jets in ls i + 61 303 , a source associated for long time with 2cg 135 + 01 and with the ues 3eg j0241 + 6103 , has given further support to this idea . finally , the very recently proposed association between the microquasar candidate ax j1639.0@xmath04642 and the ues 3eg j1639@xmath04702 points towards a population of high mass x - ray binary ( hmxb)/neutron star ( ns ) microquasars as counterparts of low - latitude unidentified egret sources . marc rib + service dastrophysique + cea saclay + bt . 709 , lorme des merisiers + f-91191 gif - sur - yvette , cedex + france . And you have already written the first three sentences of the full article: the third egret catalog ( hartman et al . @xcite ) contains 271 point sources detected at energies above 100 mev . the majority of these sources , @xmath1168 or @xmath162% , still remain unidentified . among them , there are 72 sources located at low galactic latitudes , having @xmath2@xmath310@xmath4 , which represents around 45% of the ues population .. Please generate the next two sentences of the article

therefore , several of these objects are presumably of galactic nature . similar properties between some of these uess , indicate that there are at least three different groups of galactic populations ( romero et al .

Suppose that you have an abstract for a scientific paper: we investigate the clustering properties of loose groups in the perseus pisces redshift survey . previous analyses based on cfa and ssrs surveys led to apparently contradictory results . we investigate the source of such discrepancies , finding satisfactory explanations for them . furthermore , we find a definite signal of group clustering , whose amplitude @xmath0 exceeds the amplitude @xmath1 of galaxy clustering ( @xmath2 , @xmath3 for the most significant case ; distances are measured in @xmath4 ) . groups are identified with the adaptive friends of friends ( fof ) algorithms hg ( huchra & geller 1982 ) and nw ( nolthenius & white 1987 ) , systematically varying all search parameters . correlation strenght is especially sensitive to the sky link @xmath5 ( increasing for stricter normalization @xmath6 ) , and to the ( depth @xmath7 of the ) galaxy data . it is only moderately dependent on the galaxy luminosity function @xmath8 , while it is almost insensitive to the redshift link @xmath9 ( both to the normalization @xmath10 and to the scaling recipes hg or nw ) . . And you have already written the first three sentences of the full article: galaxy , group and cluster distributions probe matter clustering in the universe , not only over different scales , but also for different density contrasts . however , while galaxy and cluster clustering have been widely inspected , a measurement of group clustering meets several conceptual and technical difficulties and it is not surprising that its results are controversial and partially contradictory . in this note we report the result of an analysis of clustering properties of loose groups in the perseus . Please generate the next two sentences of the article

pisces redshift survey ( hereafter pps ; see giovanelli , haynes , & chincarini 1986 ; haynes et al . 1988 ; giovanelli & haynes 1989 , 1991 , 1993 ) . through such analysis we believe that the reasons of previous discrepant results become clear .

Suppose that you have an abstract for a scientific paper: we study , both theoretically and experimentally , modulational instability in optical fibers that have a longitudinal evolution of their dispersion in the form of a dirac delta comb . by means of floquet theory , we obtain an exact expression for the position of the gain bands , and we provide simple analytical estimates of the gain and of the bandwidths of those sidebands . an experimental validation of those results has been realized in several microstructured fibers specifically manufactured for that purpose . the dispersion landscape of those fibers is a comb of gaussian pulses having widths much shorter than the period , which therefore approximate the ideal dirac comb . experimental spontaneous mi spectra recorded under quasi continuous wave excitation are in good agreement with the theory and with numerical simulations based on the generalized nonlinear schrdinger equation . . And you have already written the first three sentences of the full article: modulational instability ( mi ) refers to a process where a weak periodic perturbation of an intense continuous wave ( cw ) grows exponentially as a result of the interplay between dispersion and nonlinearity . mi constitutes one of the most basic and widespread nonlinear phenomena in physics , and it has been studied extensively in several different physical systems like water waves , plasmas , and optical devices @xcite . for a cubic nonlinearity , as the one occurring in the nonlinear schrdinger equation used to model optical fibers , the underlying physical mechanism can be understood in terms of four - wave mixing between the pump , signal and idler waves . however , the scalar four - wave interactions in a homogeneous fiber can be phase matched , and hence efficient , only in the anomalous group - velocity dispersion ( gvd ) regime . in the normal gvd regime , on the other hand. Please generate the next two sentences of the article

, mi can occur in detuned cavities @xcite , thanks to constructive interference between the external driving and the recirculating pulse . alternatively mi with normal gvd can also arise in systems with built - in periodic dispersion @xcite , among which dispersion oscillating fibers ( dofs ) have recently attracted renewed attention @xcite . in this case ,