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Suppose that you have an abstract for a scientific paper: the emission mechanism and the origin and structure of magnetic fields in gamma - ray burst ( grb ) jets are among the most important open questions concerning the nature of the central engine of grbs . in spite of extensive observational efforts , these questions remain to be answered and are difficult or even impossible to infer with the spectral and lightcurve information currently collected . polarization measurements will lead to unambiguous answers to several of these questions . recent developments in x - ray and @xmath0-ray polarimetry techniques have demonstrated a significant increase in sensitivity enabling several new mission concepts , e.g. _ poet _ ( polarimeters for energetic transients ) , providing wide field of view and broadband polarimetry measurements . if launched , missions of this kind would finally provide definitive measurements of grb polarizations . we perform monte carlo simulations to derive the distribution of grb polarizations in three emission models ; the synchrotron model with a globally ordered magnetic field ( so model ) , the synchrotron model with a small - scale random magnetic field ( sr model ) , and the compton drag model ( cd model ) . the results show that _ poet _ , or other polarimeters with similar capabilities , can constrain the grb emission models by using the statistical properties of grb polarizations . in particular , the ratio of the number of grbs for which the polarization degrees can be measured to the number of grbs that are detected ( @xmath1 ) and the distributions of the polarization degrees ( @xmath2 ) can be used as the criteria . if @xmath3 and @xmath2 is clustered between 0.2 and 0.7 , the so model will be favored . if instead @xmath4 , then the sr or cd model will be favored . if several events with @xmath5 are observed , then the cd model will be favored . . And you have already written the first three sentences of the full article: gamma - ray bursts ( grbs ) are brief , intense flashes of @xmath0-rays originating at cosmological distances , and they are the most luminous objects in the universe . they also have broadband afterglows long - lasting after the @xmath0-ray radiation has ceased . it has been established that the bursts and afterglows are emitted from outflows moving towards us at highly relativistic speeds @xcite , and at least some grbs are associated with the collapse of massive stars ( e.g. , * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? observations suggest that the burst is produced by internal dissipation within the relativistic jet that is launched from the center of the explosion , and the afterglow is the synchrotron emission of electrons accelerated in a collisionless shock driven by the interaction of the jet with the surrounding medium ( for recent reviews , * ? ? ?

Suppose that you have an abstract for a scientific paper: we give an explicit formula for the cohomology of a right angled artin group with group ring coefficients in terms of the cohomology of its defining flag complex . . And you have already written the first three sentences of the full article: let @xmath0 be a finite simplicial graph and let @xmath1 be the induced flag complex , i.e. , the maximal simplicial complex whose @xmath2-skeleton is @xmath0 . the associated _ right angled artin group _ @xmath3 is the group presented by @xmath4 because one can import topological properties of the associated flag complex @xmath1 into the group @xmath3 , these groups have provided important examples of exotic behavior .. Please generate the next two sentences of the article

( see for example @xcite , @xcite and @xcite . ) here we refine the understanding of the end topology of right angle artin groups by giving an explicit formula for the cohomology of @xmath3 with group ring coefficients in terms of the cohomology of @xmath1 and links of simplices in @xmath1 . if @xmath5 is a simplicial complex let @xmath6 denote the set of closed simplices including the empty simplex in @xmath5 .

Suppose that you have an abstract for a scientific paper: we introduce the notion of a _ conjugation - free geometric presentation _ for a fundamental group of a line arrangement s complement , and we show that the fundamental groups of the following family of arrangements have a conjugation - free geometric presentation : a real arrangement @xmath0 , whose graph of multiple points is a union of disjoint cycles , has no line with more than two multiple points , and where the multiplicities of the multiple points are arbitrary . we also compute the exact group structure ( by means of a semi - direct product of groups ) of the arrangement of @xmath1 lines whose graph consists of a cycle of length @xmath2 , and all the multiple points have multiplicity @xmath2 . . And you have already written the first three sentences of the full article: the fundamental group of the complement of plane curves is a very important topological invariant , which can be also computed for line arrangements . we list here some applications of this invariant . chisini @xcite , kulikov @xcite and kulikov - teicher @xcite have used the fundamental group of complements of branch curves of generic projections in order to distinguish between connected components of the moduli space of smooth projective surfaces , see also @xcite . moreover , the zariski - lefschetz hyperplane section theorem ( see @xcite ) states that @xmath3 where @xmath4 is an hypersurface and @xmath5 is a generic 2-plane .. Please generate the next two sentences of the article

since @xmath6 is a plane curve , the fundamental groups of complements of curves can be used also for computing the fundamental groups of complements of hypersurfaces in @xmath7 . a different need for fundamental groups computations arises in the search for more examples of zariski pairs @xcite .

Suppose that you have an abstract for a scientific paper: narrow - band spectral imaging with sub - pixel resolution of the _ chandra_-acis archival observation of the ulirg merger arp 220 strongly suggests two compton thick nuclei , spatially coincident with the infrared and radio emitting nuclear clusters , and separated by 1 ( @xmath0 pc at a distance of 76 mpc ) . these previously undetected highly obscured agns - west ( w ) and east ( e ) - are imaged , and separated from neighboring sources , in the 6 - 7 kev band , where the fe - k lines dominate the emission . the western nucleus is also detected at energies above 7 kev . we estimate fe - k equivalent width @xmath1 kev or possibly greater for both sources , and observed 2 - 10 kev luminosities @xmath2 ( w ) and @xmath3 ( e ) . from the observed fe - k lines luminosities , and assuming on the basis of the _ xmm - newton _ spectrum that 40% of this may be from the 6.4 kev component , we evaluate 2 - 10 kev intrinsic luminosities @xmath4 ( w ) and @xmath5 ( e ) . the inferred x - ray luminosity is at least a factor of 3 higher than that expected from a pure starburst with the bolometric luminosity of arp 220 . for a typical agn sed the bolometric luminosities are @xmath6 ( w ) and @xmath7 ( e ) . . And you have already written the first three sentences of the full article: the m-@xmath8 relation ( e.g. , * ? ? ? * ) has suggested that the evolution of galaxies and super - massive nuclear black holes ( smbhs ) are linked . both the stellar population and the smbh of a galaxy are thought to grow and evolve by merging of smaller gas - rich galaxies and their nuclear smbhs @xcite . during this process , the smbh may be buried " by thick molecular gas , which feeds the smbh at high rates , causing the birth of an obscured compton thick ( ct , * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? * ) active galactic nucleus ( agn ) .

Suppose that you have an abstract for a scientific paper: we reexamine the invariance of two - photon transition matrix elements and corresponding two - photon rabi frequencies under the `` gauge '' transformation from the length to the velocity gauge . it is shown that gauge invariance , in the most general sense , only holds at exact resonance , for both one - color as well as two - color absorption . the arguments leading to this conclusion are supported by analytic calculations which express the matrix elements in terms of hypergeometric functions , and ramified by a `` master identity '' which is fulfilled by off - diagonal matrix elements of the schrdinger propagator under a the transformation from the velocity to the length gauge . the study of the gauge dependence of atomic processes highlights subtle connections between the concept of asymptotic states , the gauge transformation of the wave function , and infinitesimal damping parameters for perturbations and interaction hamiltonians that switch off the terms in the infinite past and future [ of the form @xmath0 . we include a pertinent discussion . . And you have already written the first three sentences of the full article: a priori , the description of any dynamic process in atomic physics should be gauge invariant . yet , there is a caveat . namely , one usually calculates atomic transitions using wave functions obtained from the solution of the unperturbed schrdinger equation , and ignores both the gauge transformation of the wave function as well as the fact that the physical interpretation of the wave function changes under a gauge transformation from the velocity to the length gauge .. Please generate the next two sentences of the article

lamb @xcite has shown that if one insists on using ordinary schrdinger wave functions in off - resonant one - photon transition matrix elements , then the length gauge form has to be used for the laser field . here , we refer to off - resonant transitions as those where the frequency of the incident radiation is not exactly equal to the resonance frequency of the atom ; generalized to two - photon transitions , this implies that the sum frequency of the two photons does not exact match the energy ( frequency ) difference of the ground and excited level . for off - resonant two - photon transitions , one might think that the transition matrix element could be equal in the length and velocity gauges if all possible intermediate , virtual states are included in the calculation .

Suppose that you have an abstract for a scientific paper: we have shown that non - zero @xmath0 is generated in a see - saw type softly broken @xmath1 symmetric model through a single parameter perturbation in @xmath2 in a single element . we have explored all possible 9 cases to study the neutrino mixing angles considering the best fitted values of @xmath3 and @xmath4 with all parameters real . we have extended our analysis for the complex case and demonstrated large low energy cp violation ( @xmath5 ) and @xmath6 in addition to mixing and mass pattern . we have also investigated leptogenesis and for a reasonable choice of model parameters compatible with low energy data , wmap value of baryon asymmetry @xmath7 is obtained for right handed neutrino mass scale @xmath8 gev . we have obtained a relation among the phases responsible for leptogenesis and have shown that those phases also have correlations with low energy cp violating phases . pacs number(s ) : 14.60.pq , 11.30.hv , 98.80.cq . And you have already written the first three sentences of the full article: in recent time people are too much interested to find some flavor symmetry in order to generate mass and mixing pattern of fermions . continuous symmetry like @xmath9 @xcite , @xmath10 @xcite symmetry and most popular discrete symmetry , @xmath11 exchange symmetry ( @xmath12@xcite have got some success to describe mass and mixing pattern in leptonic sector . to avoid mass degeneracy of @xmath13 and @xmath14 under @xmath15 symmetry , e. ma and g. rajasekaran in @xcite have introduced first time the @xmath1 symmetry .. Please generate the next two sentences of the article

after this paper , a lot of work have done with this symmetry @xcite-@xcite . after introduction of tri - bi maximal mixing pattern ( @xmath16 , @xmath17 , @xmath18)@xcite , people have tried to fit this mixing pattern through the @xmath1 symmetry . in an well motivated extension of the standard model through the inclusion of @xmath1 discrete symmetry tri - bi

Suppose that you have an abstract for a scientific paper: constrained density functional theory ( cdft ) is used to evaluate the energy level alignment of a benzene molecule as it approaches a graphene sheet . within cdft the problem is conveniently mapped onto evaluating total energy differences between different charge - separated states , and it does not consist in determining a quasi - particle spectrum . we demonstrate that the simple local density approximation provides a good description of the level aligmnent along the entire binding curve , with excellent agreement to experiments at an infinite separation and to @xmath0 calculations close to the bonding distance . the method also allows us to explore the effects due to the presence of graphene structural defects and of multiple molecules . in general all our results can be reproduced by a classical image charge model taking into account the finite dielectric constant of graphene . . And you have already written the first three sentences of the full article: organic molecular crystals , namely crystals composed of organic molecules held together by weak van der waals forces , are emerging as excellent candidates for fabricating nanoscale devices . these have potential application in electronics and optoelectronics in particular in areas such as solar energy harvesting , surface photochemistry , organic electronics and spintronics @xcite . a feature common to such class of devices is that they are composed from both an organic and inorganic component , where the first forms the active part of the device and the second provides the necessary electrical contact to the external circuitry .. Please generate the next two sentences of the article

clearly the electronic structure of the interface between these two parts plays a crucial role in determining the final device performance and needs to be understood carefully . in particular it is important to determine how charge transfers between the organic and the inorganic component and the energies at which the transfer takes place .

Suppose that you have an abstract for a scientific paper: using first - principles plane - wave calculations study of electronic and magnetic properties of hypothetical two - dimensional structure of li@xmath0n compound have been conducted . calculations show , that electronic properties of this this structure can be inflenced by hydrogenation , which may change the system from wide - gap semiconductor to metal . also , non - zero magnetic moment , equal to 1 @xmath1 can be generated by intruduction of h vacanies in hydrogenated structure . . And you have already written the first three sentences of the full article: since its discovery in 2004 graphene @xcite draws much attention because of unique features of this two - dimensional system . graphene is composed of a sp@xmath2-bonded carbon atoms forming honeycomb structure . it became famous for its very interesting electronic structure with characteristic , linear energy dispersion near k point of brillouin zone and many other features @xcite .. Please generate the next two sentences of the article

shortly after , experimental techniques allowed fabrication of other new two - dimensional materials , like bn and mos@xmath3 honeycomb structures @xcite . the discovery of such stable two - dimensional materials triggered search for similar structures made from different compounds .

Suppose that you have an abstract for a scientific paper: this paper studies _ the nash stability _ in hedonic coalition formation games . we address the following issue : for a general problem formulation , is there any utility allocation method ensuring a nash - stable partition ? we propose the definition of _ the nash - stable core _ and we analyze the conditions for having a non - empty nash - stable core . more precisely , we prove that using relaxed efficiency in utility sharing allows to ensure a non empty nash - stable core . then , a decentralized algorithm called _ nash stability establisher _ is proposed for finding the nash stability in a game whenever at least one exists . the problem of finding the nash stability is formulated as a non - cooperative game . in the proposed approach , during each round , each player determines its strategy in its turn according to a _ random round - robin scheduler_. we prove that the algorithm converges to an equilibrium if it exists , which is the indicator of the nash stability . . And you have already written the first three sentences of the full article: any cooperation among agents ( players ) being able to make strategic decisions becomes a _ coalition formation game _ when the players may for various personal reasons wish to belong to a relative _ small coalition _ rather than the `` grand coalition '' . partitioning players represents the crucial question in the game context and a stable partition of the players is referred to as an equilibrium . in @xcite , the authors propose an abstract approach to coalition formation that focuses on simple merge and split stability rules transforming partitions of a group of players . the results are parametrized by a preference relationship between partitions from the point of view of each player .. Please generate the next two sentences of the article

on the other hand , a coalition formation game is called to be _ hedonic _ if * _ the gain of any player depends solely on the members of the coalition to which the player belongs _ , and * _ the coalitions form as a result of the preferences of the players over their possible coalitions set_. accordingly , the stability concepts aiming _ hedonic conditions _ can be summarized as following @xcite : a partition could be _ individually stable , nash stable , core stable , strict core stable , pareto optimal , strong nash stable , strict strong nash stable_. in the sequel , we concentrate on the nash stability . the definition of the nash stability is quite simple : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ a partition of players is nash stable whenever there is no player deviating from his / her coalition to another coalition in the partition_. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ we refer to @xcite for further discussions concerning the stability concepts in the context of hedonic coalition formation games . in @xcite , the problem of generating nash stable solutions in coalitional games is considered . in particular , the authors proposed an algorithm for constructing the set of all nash stable coalition structures from players preferences in a given additively separable hedonic game . in @xcite , a bargaining procedure of coalition formation in the class of hedonic games , where players preferences depend solely on the coalition they belong to is studied .

Suppose that you have an abstract for a scientific paper: within mean - field theory we calculate the scaling functions associated with critical casimir forces for a system consisting of two spherical colloids immersed in a binary liquid mixture near its consolute point and facing a planar , homogeneous substrate . for several geometrical arrangements and boundary conditions we analyze the normal and the lateral critical casimir forces acting on one of the two colloids . we find interesting features such as a change of sign of these forces upon varying either the position of one of the colloids or the temperature . by subtracting the pairwise forces from the total force we are able to determine the many - body forces acting on one of the colloids . we have found that the many - body contribution to the total critical casimir force is more pronounced for small colloid - colloid and colloid - substrate distances , as well as for temperatures close to criticality , where the many - body contribution to the total force can reach up to @xmath0 . . And you have already written the first three sentences of the full article: the first step in describing the interaction between many particles is to determine their pair potential or the forces among a single pair . if the governing physical equations are linear ( like for gravity or electrostatics ) , this approach yields a quantitatively reliable description of the physical system considered , based on the linear superposition principle . however , if nonlinearities are present , linear superposition of pair potentials is no longer accurate and nonadditivity gives rise to many - body effects .. Please generate the next two sentences of the article

these latter effects can lead , e.g. , to a strengthening or weakening of the total force acting on a particle surrounded by more than a single other one , a change of sign of that force , or the appearance of stable or unstable configurations . many - body effects appear in rather diverse systems such as nuclear matter , superconductivity @xcite , colloidal suspensions @xcite , quantum - electrodynamic casimir forces @xcite , polymers @xcite , nematic colloids @xcite , and noble gases with van der waals forces acting among them @xcite . each of these systems is characterized by a wide range of time and length scales . integrating out the degrees of freedom associated with small scales ( such as the solvent of colloidal solutes or polymers ) for fixed configurations of the large particles , generates effective interactions among the latter , which are inherently not pairwise additive .

Suppose that you have an abstract for a scientific paper: a class of potential backgrounds for higgs boson searches in the @xmath0 channel at both the tevatron and large hadron collider is presented . backgrounds from @xmath1 production with _ external _ conversion of the on - shell photon in detector material to an asymmetric electron positron pair , @xmath2 , with loss of the trailing electron or positron has been treated adequately in higgs searches . here we consider analogous backgrounds from @xmath3 production with _ internal _ conversion of the off - shell photon in vacuum to an asymmetric lepton anti - lepton pair @xmath4 . while the former process yields almost entirely electrons or positrons , the latter can give electron , positron , muon , and anti - muon backgrounds in roughly equal amounts . we estimate that asymmetric internal conversion backgrounds are comparable to the higgs boson signal in the standard signal region of phase space . these processes also represent potential backgrounds for new physics searches in same - sign di - lepton channels . some data driven methods to characterize asymmetric internal conversion backgrounds are suggested . ru - nhetc-2011 - 16 + uttg-20 - 11 + tcc-022 - 11 + 1.0 in * backgrounds to higgs boson searches from * + * @xmath5 asymmetric internal conversion * 0.65 in richard c. gray@xmath6 can kilic@xmath7 michael park@xmath6 0.1 in sunil somalwar@xmath6 and scott thomas@xmath6 0.25 in @xmath6_department of physics + rutgers university + piscataway , nj 08854 _ 0.15 in @xmath8 _ theory group , department of physics and texas cosmology center + the university of texas at austin + austin , tx 78712 _ 0.75 in . And you have already written the first three sentences of the full article: the search for the higgs boson has been the cornerstone of the physics program at modern high energy colliders . the higgs boson of the standard model has well defined production and decay modes that allow for mass dependent searches in a number of channels . one of the key discovery modes at hadron colliders is higgs boson production by gluon - gluon fusion with decay through two leptonically decaying @xmath9-bosons , @xmath10 , giving opposite sign di - leptons plus missing energy .. Please generate the next two sentences of the article

the dominant background in this channel comes from electroweak pair production of @xmath9-bosons , @xmath11 . this background is substantially larger than the higgs boson signal .

Suppose that you have an abstract for a scientific paper: we discuss the lift of certain d6-antid6-brane systems to m - theory . these are purely gravitational configurations with a bolt singularity . when reduced along a trivial circle , and for large bolt radius , the bolt is related to a non - supersymmetric orbifold type of singularity where some closed string tachyons are expected in the twisted sectors . this is a kind of open - closed string duality that relates open string tachyons on one side and localised tachyons in the other . we consider the evolution of the system of branes from the m - theory point of view . this evolution gives rise to a brane - antibrane annihilation on the brane side . on the gravity side , the evolution is related to a reduction of the order of the orbifold and to a contraction of the bolt to a nut or flat space if the system has non - vanishing or vanishing charge , respectively . we also consider the inverse process of reducing a non - supersymmetric orbifold to a d6-brane system . for @xmath0 , the reduced system is a fractional d6-brane at an orbifold singularity @xmath1 . cern/2002 - 066 + wis/12/02-mar - dpp + hep - th/0203243 + 0.3 cm 10.mm * ral rabadn @xmath2 and joan simn @xmath3 * + @xmath4 theory division cern , + ch-1211 genve 23 , switzerland + .5 cm @xmath5 department of particle physics , the weizmann institute of science + herzl street 2 , 76100 rehovot , israel + _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ' '' '' width 5.cm 2.mm @xmath6 e - mail : raul.rabadan@cern.ch + @xmath7 e - mail : jsimon@weizmann.ac.il + _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . And you have already written the first three sentences of the full article: it is well known that the lift to m - theory of a system of parallel d6-branes @xcite corresponds to a purely geometric background , the taub - nut metric . when the position of n of these d6-branes coincide , one gets an @xmath8 singularity at a point in the multi taub - nut space . in this paper , we would like to make a step forward in the relation between the physics of d6-branes at strong coupling and purely gravitational backgrounds in eleven dimensional supergravity by studying the lift of a system of coincident d6-@xmath9 branes to m - theory .. Please generate the next two sentences of the article

we shall primarily be concerned with the geometry describing these configurations , its evolution as branes and antibranes annihilate each other and some similarities between the qualitative patterns that we find in this evolution and some recent results on the evolution due to the condensation of localised closed string tachyons in non - supersymmetric orbifold singularities @xcite . in particular , we shall study the lift to m - theory of the generically non - bps configurations found in @xcite preserving @xmath10 .

Suppose that you have an abstract for a scientific paper: molecular hydrogen is the most abundant molecule in the universe . a large fraction of h@xmath0 forms by association of hydrogen atoms adsorbed on polycyclic aromatic hydrocarbons ( pahs ) , where formation rates depend crucially on the h sticking probability . we have experimentally studied pah hydrogenation by exposing coronene cations , confined in a radiofrequency ion trap , to gas phase atomic hydrogen . a systematic increase of the number of h atoms adsorbed on the coronene with the time of exposure is observed . odd coronene hydrogenation states dominate the mass spectrum up to 11 h atoms attached . this indicates the presence of a barrier preventing h attachment to these molecular systems . for the second and fourth hydrogenation , barrier heights of 72 @xmath1 6 mev and 40 @xmath1 10 mev , respectively are found which is in good agreement with theoretical predictions for the hydrogenation of neutral pahs . our experiments however prove that the barrier does not vanish for higher hydrogenation states . these results imply that pah cations , as their neutral counterparts , exist in highly hydrogenated forms in the interstellar medium . due to this catalytic activity , pah cations and neutrals seem to contribute similarly to the formation of h@xmath0 . . And you have already written the first three sentences of the full article: molecular hydrogen is the most abundant molecule in the universe and the main constituent of regions where stars are forming . h@xmath2 plays an important role in the chemistry of the interstellar medium , and its formation governs the transformation of atomic diffuse clouds into molecular clouds . because of the inefficient gas phase routes to form h@xmath2 , dust grains have been recognized to be the favored habitat to form h@xmath2 molecules ( @xcite , @xcite ) . the sticking of h atoms onto surfaces has received considerable attention because this mechanism governs the formation of h@xmath2 , but also other molecules that contain h atoms .. Please generate the next two sentences of the article

the sticking of h atoms onto dust grains can also be an important mechanism to cool interstellar gas ( @xcite ) . in the past decades , a plethora of laboratory experiments and theoretical models have been developed to understand how h@xmath2 forms .

Suppose that you have an abstract for a scientific paper: a clock steps a computer through a cycle of phases . for the propagation of logical symbols from one computer to another , each computer must mesh its phases with arrivals of symbols from other computers . even the best atomic clocks drift unforeseeably in frequency and phase ; feedback steers them toward aiming points that depend on a chosen wave function and on hypotheses about signal propagation . a wave function , always under - determined by evidence , requires a guess . guessed wave functions are coded into computers that steer atomic clocks in frequency and position clocks that step computers through their phases of computations , as well as clocks , some on space vehicles , that supply evidence of the propagation of signals . recognizing the dependence of the phasing of symbol arrivals on guesses about signal propagation elevates ` logical synchronization . ' from its practice in computer engineering to a dicipline essential to physics . within this discipline we begin to explore questions invisible under any concept of time that fails to acknowledge the unforeseeable . in particular , variation of spacetime curvature is shown to limit the bit rate of logical communication . . And you have already written the first three sentences of the full article: as is well known , the atom or atoms in the atomic clock are passive they do not `` tick''so the clock needs an active oscillator in addition to the atom(s ) . in designing an atomic clock to realize the second as a measurement unit in the international system of units ( si ) , one encounters two problems : ( a ) the resonance exhibited by the atom or atoms of the clock varies with the details of the clock s construction and the circumstances of its operation ; in particular the resonance shifts depending on the intensity of the radiation of the atoms by the oscillator . ( b ) the oscillator , controlled by , in effect , a knob , drifts in relation to the knob setting . problem ( a ) is dealt with by introducing a wave function parametrized by radiation intensity and whatever other factors one deems relevant .. Please generate the next two sentences of the article

the si second is then `` defined '' by the resonance that `` would be found '' at absolute zero temperature ( implying zero radiation ) . for a clock using cesium 133 atoms , this imagined resonance is declared by the general conference of weights and measures to be 9 192 631 770 hz , so that the si second is that number of cycles of the radiation at that imagined resonance @xcite . to express the relation between a measured resonance and the imagined resonance at 0 k

Suppose that you have an abstract for a scientific paper: cracks are created by massive breakage of molecular or atomic bonds . the latter , in its turn , leads to the highly localized loss of material , which is the reason why even closed cracks are visible by a naked eye . thus , fracture can be interpreted as the local material sink . mass conservation is violated locally in the area of material failure . we consider a theoretical formulation of the coupled mass and momenta balance equations for a description of fracture . our focus is on brittle fracture and we propose a finite strain hyperelastic thermodynamic framework for the coupled mass - flow - elastic boundary value problem . the attractiveness of the proposed framework as compared to the traditional continuum damage theories is that no internal parameters ( like damage variables , phase fields etc . ) are used while the regularization of the failure localization is provided by the physically sound law of mass balance . . And you have already written the first three sentences of the full article: within the framework of continuum mechanics there are surface and bulk material failure models . surface failure models are known by name of cohesive zone models ( czms ) . in the latter case , continuum is enriched with discontinuities along surfaces - cohesive zones - with additional traction - displacement - separation constitutive laws .. Please generate the next two sentences of the article

these laws are built qualitatively as follows : traction increases up to a maximum and then goes down to zero via increasing separation ( barenblatt , 1959 ; needleman , 1987 ; rice and wang , 1989 , tvergaard and hutchinson , 1992 ; camacho and ortiz , 1996 ; de borst , 2001 ; xu and needleman , 1994 ; roe and siegmund , 2003 ; moes et al , 1999 ; park et al , 2009 ; gong et al , 2012 ) . if the location of the separation surface is known in advance ( e.g. fracture along weak interfaces ) then the use of czm is natural .

Suppose that you have an abstract for a scientific paper: we consider an anderson impurity model in which the locally correlated orbital is coupled to a host with a gapped density of states . single - particle dynamics are studied , within a perturbative framework that includes both explicit second - order perturbation theory and self - consistent perturbation theory to all orders in the interaction . away from particle - hole symmetry the system is shown to be a generalized fermi liquid ( gfl ) in the sense of being perturbatively connectable to the non - interacting limit ; and the exact friedel sum rule for the gfl phase is obtained . we show by contrast that the particle - hole symmetric point of the model is not perturbatively connected to the non - interacting limit , and as such is a non - fermi liquid for all non - zero gaps . our conclusions are in agreement with nrg studies of the problem . . And you have already written the first three sentences of the full article: the anderson impurity model ( aim ) , in which a single , locally correlated orbital couples to a non - interacting metallic band of electrons , is a longstanding paradigm of strongly - correlated electron physics . conceived originally@xcite to explain the formation of localized magnetic moments on impurities in non - magnetic hosts , it has since formed the cornerstone of our understanding of the kondo effect@xcite and related many - body phenomena . interest in the area is currently particularly strong , both experimentally and theoretically , after the kondo effect was predicted@xcite and then directly confirmed@xcite to arise in mesoscopic quantum dot systems.@xcite after some 50 years of intense theoretical work , the spin-@xmath0 kondo effect as manifest in anderson s original model is naturally rather well understood@xcite .. Please generate the next two sentences of the article

below some characteristic kondo temperature @xmath1 , a complex many - body state develops in which the impurity spin is completely screened by the host metal , leading at low energies to a ` local ' fermi - liquid and universal transport properties . being a low - energy phenomenon , the kondo effect is of course crucially dependent on both conduction band states near the fermi level and the low - energy spin degrees of freedom of the impurity .

Suppose that you have an abstract for a scientific paper: we investigate the signatures at the large hadron collider of a minimal model where the dark matter particle is a majorana fermion that couples to the standard model via one or several coloured mediators . we emphasize the importance of the production channel of coloured scalars through the exchange of a dark matter particle in the t - channel , and perform a dedicated analysis of searches for jets and missing energy for this model . we find that the collider constraints are highly competitive compared to direct detection , and can even be considerably stronger over a wide range of parameters . we also discuss the complementarity with searches for spectral features at gamma - ray telescopes and comment on the possibility of several coloured mediators , which is further constrained by flavour observables . . And you have already written the first three sentences of the full article: despite the mounting evidence for the existence of dark matter ( dm ) in galaxies , clusters of galaxies and the universe at large scale , the nature and properties of the dark matter particle are still largely unconstrained by observations . in fact , viable dark matter models have been constructed with masses ranging between @xmath0ev and @xmath1 gev , and interaction cross sections ranging between @xmath2 pb and @xmath3 pb ( for a review , see @xcite ) . in this vast parameter space of dark matter models , weakly interacting massive particles ( wimps ) still stand as one of the most promising dark matter candidates , since for reasonable values of the model parameters , the freeze - out of dark matter wimps from the thermal plasma left a relic population with an abundance which reproduces qualitatively well the measured value of the dark matter density @xmath4 @xcite . there are presently three different approaches pursued in order to detect the non - gravitational effects of wimps with ordinary matter : direct detection , indirect detection and collider experiments .. Please generate the next two sentences of the article

this decade is being especially prolific in experimental results in the three search strategies . indeed , various experiments currently in operation are setting strong limits on the wimp parameter space and ruling out regions where a dark matter signal could be expected , notably xenon100 @xcite and lux @xcite in direct searches , fermi - lat @xcite , ams-02 @xcite , h.e.s.s .

Suppose that you have an abstract for a scientific paper: let @xmath0 be a vector space over a field or skew field @xmath1 , and let @xmath2 be its subspace . we study the canonical form problem for bilinear or sesquilinear forms @xmath3 and linear mappings @xmath4 @xmath5 @xmath6 @xmath7 we solve it over @xmath8 and reduce it over all @xmath1 to the canonical form problem for ordinary linear mappings @xmath9 and bilinear or sesquilinear forms @xmath10 . moreover , we give an algorithm that realizes this reduction . the algorithm uses only unitary transformations if @xmath11 , which improves its numerical stability . for linear mapping this algorithm can be derived from the algorithm by l. a. nazarova , a. v. roiter , v. v. sergeichuk , and v. m. bondarenko [ _ j . soviet math . _ 3 ( no . 5 ) ( 1975 ) 636654 ] . _ ams classification : _ 15a21 , 15a63 _ keywords : _ canonical matrices ; classification ; linear operators ; bilinear and sesquilinear forms [ theorem]lemma [ theorem]definition . And you have already written the first three sentences of the full article: in this paper , we give canonical matrices of bilinear or sesquilinear forms @xmath12 where @xmath0 is a complex vector space and @xmath2 is its subspace . we use the following canonical matrices of bilinear or sesquilinear forms on a complex vector space given in @xcite ( see also @xcite ) . two square complex matrices @xmath13 and @xmath14 are said to be _ congruent _ or * _ congruent _ if there is a nonsingular @xmath15 such that @xmath16 or , respectively , @xmath17 , where @xmath18 denotes the complex conjugate transpose of @xmath15 .. Please generate the next two sentences of the article

define the @xmath19-by-@xmath19 matrices @xmath20 @xmath21 [ @xcite ] [ bilin ] ( a ) every square complex matrix is congruent to a direct sum , determined uniquely up to permutation of summands , of matrices of the form @xmath22 in which @xmath23 , @xmath24 , and @xmath25 is determined up to replacement by @xmath26 . \(b ) every square complex matrix is congruent to a direct sum , determined uniquely up to permutation of summands , of matrices of the form @xmath27 in which @xmath28 and @xmath29 .

Suppose that you have an abstract for a scientific paper: the large and rapidly varying electric and magnetic fields induced by the spectator systems moving at ultrarelativistic velocities induce a charge splitting of directed flow , @xmath0 , of positive and negative pions in the final state of the heavy ion collision . the same effect results in a very sizeable distortion of charged pion spectra as well as ratios of charged pions ( @xmath1 ) emitted at high values of rapidity . both phenomena are sensitive to the actual distance between the pion emission site and the spectator system . this distance @xmath2 appears to decrease with increasing rapidity of the pion , and comes below @xmath31 fm for pions emitted close to beam rapidity . in this paper we discuss how these findings can shed new light on the space - time evolution of pion production as a function of rapidity , and on the longitudinal evolution of the system created in heavy ion collisions . . And you have already written the first three sentences of the full article: the presence of large and rapidly varying electric and magnetic fields in relativistic heavy ion collisions results in charge - dependent effects , visible in a series of observables in the final state of the collision . these effects can be used as a new source of information on the space - time evolution of the non - perturbative process of particle production , and on the space - time properties of the system created in the heavy ion collision . to give one example , in 2007 we demonstrated that the distortion which the electromagnetic repulsion ( attraction ) of positive ( negative ) pions induced on charged pion ( @xmath1 ) ratios brought new information on the space - time scenario of fast pion production @xcite . in recent years , the general problematics of electromagnetically - induced effects in ultrarelativistic heavy ion reactions was subject of an important theoretical and experimental interest @xcite as it was connected to very interesting phenomena like the chiral magnetic effect ( cme @xcite ) . in the present paper we review our earlier studies of the electromagnetic distortion of charged pion spectra in the context of our more recent findings on the influence of spectator - induced @xmath4 and @xmath5 fields on the azimuthal anisotropies of charged pions .. Please generate the next two sentences of the article

special attention is put on tracing the utility of both observables for studying the longitudinal evolution of the expanding matter created in the collision . a phenomenological model analysis is presented , aimed at explaining the space - time features of pion production which we deduced from the observed electromagnetic phenomena .

Suppose that you have an abstract for a scientific paper: the decay of the @xmath0 boson into supersymmetric particles is studied . we investigate how these supersymmetric modes affect the current limits from the tevatron and project the expected sensitivities at the lhc . employing three representative supersymmetric @xmath0 models , namely , @xmath1 , @xmath2 , and the sequential model , we show that the current limits of the @xmath0 mass from the tevatron could be reduced substantially due to the weakening of the branching ratio into leptonic pairs . the mass reach for the @xmath1 @xmath0 bosons is about @xmath3 tev at the lhc-7 ( 1 fb@xmath4 ) , about @xmath5 tev at the lhc-10 ( 10 fb@xmath4 ) , and about @xmath6 tev at the lhc-14 ( 100 fb@xmath4 ) . a similar mass reach for the @xmath2 @xmath0 is also obtained . we also examine the potential of identifying various supersymmetric decay modes of the @xmath0 boson because it may play a crucial role in the detailed dynamics of supersymmetry breaking . . And you have already written the first three sentences of the full article: existence of extra neutral gauge bosons has been predicted in many extensions of the standard model ( sm ) @xcite . string - inspired models and grand - unification ( gut ) models usually contain a number of extra @xmath7 symmetries , beyond the hypercharge @xmath8 of the sm . the exceptional group @xmath1 is one of the famous examples of this type @xcite .. Please generate the next two sentences of the article

these extra @xmath7 s are broken at some intermediate energy scales between the gut and the electroweak scales . phenomenologically , the most interesting option is the breaking of these @xmath7 s at around tev scales , giving rise to extra neutral gauge bosons observable at the tevatron and the large hadron collider ( lhc ) .

Suppose that you have an abstract for a scientific paper: we describe numerical simulations , using the particle - in - cell ( pic ) and hybrid - pic code lsp [ t. p. hughes et al . , phys . rev . st accel . beams * 2 * , 110401 ( 1999 ) ] , of the head - on merging of two laboratory supersonic plasma jets . the goals of these experiments are to form and study astrophysically relevant collisionless shocks in the laboratory . using the plasma jet initial conditions ( density @xmath0@xmath1 @xmath2 , temperature @xmath3 few ev , and propagation speed @xmath4100 km / s ) , large - scale simulations of jet propagation demonstrate that interactions between the two jets are essentially collisionless at the merge region . in highly resolved one- and two - dimensional simulations , we show that collisionless shocks are generated by the merging jets when immersed in applied magnetic fields ( @xmath51 kg ) . at expected plasma jet speeds of up to 100 km / s , our simulations do not give rise to unmagnetized collisionless shocks , which require much higher velocities . the orientation of the magnetic field and the axial and transverse density gradients of the jets have a strong effect on the nature of the interaction . we compare some of our simulation results with those of previously published pic simulation studies of collisionless shock formation . . And you have already written the first three sentences of the full article: collisionless shocks @xcite play an important role in energy transport and evolution of charged - particle distribution functions in space and astrophysical environments . although collisionless shocks in plasmas were first predicted in the 1950s @xcite and discovered in the 1960s @xcite , many questions relating to the microscopic physics of collisionless shock formation , evolution , and shock acceleration of particles to very high energies remain unanswered @xcite . laboratory studies of collisionless shocks have been conducted since the 1960s @xcite , but a recent renaissance of laboratory collisionless shock experiments @xcite stems from the fact that modern laboratory plasmas can satisfy key physics criteria for the shocks to have `` cosmic relevance '' @xcite .. Please generate the next two sentences of the article

recently initiated experiments @xcite at los alamos national laboratory ( lanl ) aim to form and study astrophysically relevant collisionless shocks via the head - on merging of two supersonic plasma jets , each with order 10-cm spatial scale size . compared to most other modern collisionless shock experiments which use laser - produced or wire - array z - pinch @xcite plasmas , the lanl experiment has larger shock spatial size ( up to 30-cm wide and a few - cm thick ) and longer shock time duration ( order 10 @xmath6s ) but somewhat lower sonic and alfvn mach numbers .

Suppose that you have an abstract for a scientific paper: the kloe experiment at the da@xmath0ne @xmath1-factory has performed a new precise measurement of the pion form factor using initial state radiation events , with photons emitted at small polar angle . results based on an integrated luminosity of 240 pb@xmath2 and extraction of the @xmath3 contribution to @xmath4 in the mass range @xmath5 $ ] gev@xmath6 are presented , the systematic uncertainty is reduced with respect to the published kloe result . . And you have already written the first three sentences of the full article: the anomalous magnetic moment of the muon has recently been measured to an accuracy of 0.54 ppm @xcite . the main source of uncertainty in the value predicted @xcite in the standard model is given by the hadronic contribution , @xmath7 , to the lowest order . this quantity is estimated with a dispersion integral of the hadronic cross section measurements. Please generate the next two sentences of the article

. in particular , the pion form factor , @xmath8 , defined via @xmath9 , accounts for @xmath10 of the central value and for @xmath11 of the uncertainty in @xmath7 . the kloe experiment already published @xcite a measurement of @xmath8 with the method described below , using an integrated luminosity of 140 pb@xmath2 , taken in 2001 , henceforth referred to as kloe05 .

Suppose that you have an abstract for a scientific paper: a fuzzy circle and a fuzzy 3-sphere are constructed as subspaces of fuzzy complex projective spaces , of complex dimension one and three , by modifying the laplacians on the latter so as to give unwanted states large eigenvalues . this leaves only states corresponding to fuzzy spheres in the low energy spectrum ( this allows the commutative algebra of functions on the continuous sphere to be approximated to any required degree of accuracy ) . the construction of a fuzzy circle opens the way to fuzzy tori of any dimension , thus circumventing the problem of power law corrections in possible numerical simulations on these spaces . . And you have already written the first three sentences of the full article: one of the principal goals of the study of field theories on fuzzy spaces is to develop an alternative non - perturbative technique to the familiar lattice one @xcite . to date , this new approach in the case of four dimensional field theories has been limited to studies of euclidean field theory on @xmath0 @xcite , @xmath1 @xcite and @xmath2 @xcite . all but @xmath0 have additional complications . for example , @xmath1 is not spin but spin@xmath3 and @xmath2 is really a squashed @xmath4 and includes many unwanted massive kaluza - klein type modes .. Please generate the next two sentences of the article

even @xmath0 is not ideal since it has curvature effects that drop off as power corrections rather than exponentially as in the case of toroidal geometries . the fuzzy approach does , however , have the advantage of preserving continuous symmetries such as the @xmath5 symmetry of a round @xmath6 and does not suffer from fermion doubling @xcite .

Suppose that you have an abstract for a scientific paper: we measure the projected rotational velocities of the late b - type hypervelocity stars hvs7 and hvs8 from high resolution spectroscopy to be 60 @xmath0 17 km s@xmath1 and 260 @xmath0 70 km s@xmath1 . the slow rotation of hvs7 is in principle consistent with having originated in a binary system , assuming a high inclination angle of the stellar rotation axis . however , the fast rotation of hvs8 is more typical of single b - type stars . hvs8 could have therefore been ejected by a mechanism other than that proposed by hills . we also estimate the effective temperatures and surface gravities for hvs7 and hvs8 and obtain an additional measurement of their radial velocities . we find evidence in support of a blue horizontal branch nature for hvs7 , and a main sequence nature for hvs8 . . And you have already written the first three sentences of the full article: the recent discovery of 10 hypervelocity stars ( hvss ; * ? ? ? * ; * ? ? ? * ; * ? ? ?. Please generate the next two sentences of the article

* ; * ? ? ? * ; * ? ? ?

Suppose that you have an abstract for a scientific paper: we present an exactly solvable model of a classical dielectric medium that gives an unambiguous local decomposition of field and charge motion and their contribution to the conserved quantities . the result is a set of four branches to the dispersion law that gives full independent freedom in the selection of initial data of the fields and charge motion , in contrast with constitutive laws . this is done with special care to the forces that exist at surfaces , coatings and the ends of packets . as a result the utility of a stress - tensor as a function of field strengths and dielectric response for deriving general forces is called into question . the abraham - minkowskii paradox is clarified from this point of view and the export of such notions to realistic media and metamaterials are discussed . one result of this model is a mathematically simpler and more intuitive understanding of causality in media than the brillouin and sommerfeld theories . necessary elastic medium response is estimated and some implications of this picture for quantum effects are included based on conservation laws . this model can be extended to manifestly maintain these features as general nonlinear and time and space dependent changes in medium response are introduced . the extent to which this can provide a universal description for all dielectrics is discussed . a microscopic treatment of negative index materials from this point of view is included as an illustration of the extreme economy and simplicity of these methods . the abraham - minkowskii paradox has led to a century long debate on the proper assignment of momentum to electromagnetic waves in media @xcite . minkowskii argued that the momentum of a photon should be @xmath0 and abraham as @xmath1 . some now argue that this is now resolved and both assignments are correct when boundary conditions are correctly applied @xcite . the purpose of this article is not so much to dispute that position but to view this problem and general dielectric.... And you have already written the first three sentences of the full article: generally , discussions of theory of dielectric response begin very formally and derive the lorentz - drude model by introducing a complex dielectric function that gives an out - of - phase damping term . in real space this corresponds to a spatially and temporally local damping term . often there is an appeal to the transfer functions of a localized driven damped oscillators as a strong analogy .. Please generate the next two sentences of the article

however , the driving and damping are due to fields that are being changed by the motion of the charges and it is easy to get lost in the rather formal definitions of the `` macroscopic '' variables @xmath2 and @xmath3 . if we were to construct a complete basis of the system one might wonder how there can be any damping at all . the radiational degrees of freedom combined with the electron oscillations and core vibrations are all that exist in the theory .

Suppose that you have an abstract for a scientific paper: we report on a new experimental platform for the measurement of absolute scattering cross - sections . the target atoms are trapped in an optical dipole trap and are exposed to an incident particle beam . the exponential decay of the atom number directly yields the absolute total scattering cross - section . the technique can be applied to any atomic or molecular species that can be prepared in an optical dipole trap and provides a large variety of possible scattering scenarios . . And you have already written the first three sentences of the full article: a gaseous atomic target with very low momentum spread is an ideal starting point for atomic scattering experiments . this was demonstrated with great success by the invention of the coltrims ( cold target recoil ion momentum spectroscopy ) technique @xcite . while in coltrims experiments , the target is an atomic beam with low transverse momentum spread , the advent of laser cooling and trapping has provided a related platform . it is known as motrims ( magneto - optical trap recoil ion momentum spectroscopy ) @xcite , and uses an atomic cloud as target which is cooled in all three spatial dimensions with a magneto - optical trap .. Please generate the next two sentences of the article

the achievable temperature of @xmath0 100@xmath1k corresponds to an energy spread of only 10nev . the above mentioned experiments focus on charged reaction products which can be detected with a position sensitive micro - channel plate .

Suppose that you have an abstract for a scientific paper: a new , improved split - step backward euler ( ssbe ) method is introduced and analyzed for stochastic differential delay equations(sddes ) with generic variable delay . the method is proved to be convergent in mean - square sense under conditions ( assumption [ olc ] ) that the diffusion coefficient @xmath0 is globally lipschitz in both @xmath1 and @xmath2 , but the drift coefficient @xmath3 satisfies one - sided lipschitz condition in @xmath1 and globally lipschitz in @xmath2 . further , exponential mean - square stability of the proposed method is investigated for sddes that have a negative one - sided lipschitz constant . our results show that the method has the unconditional stability property in the sense that it can well reproduce stability of underlying system , without any restrictions on stepsize @xmath4 . numerical experiments and comparisons with existing methods for sddes illustrate the computational efficiency of our method . + * ams subject classification : * 60h35,65c20,65l20 . + * key words : * split - step backward euler method , strong convergence , one - sided lipschitz condition , exponential mean - square stability , mean - square linear stability . And you have already written the first three sentences of the full article: in this paper we consider the numerical integration of autonomous stochastic differential delay equations ( sddes ) in the it s sense @xmath5 with initial data @xmath6 $ ] . here @xmath7 is a delay term satisfying @xmath8 and @xmath9 , @xmath10 . we assume that the initial data is independent of the wiener measure driving the equations and @xmath11 is an @xmath12-dimensional wiener process defined on the complete probability space @xmath13 with a filtration @xmath14 satisfying the usual conditions ( that is , it is increasing and right continuous while @xmath15 contains all @xmath16-null sets ) . for a given constant stepsize @xmath17 , we propose a split - step backward euler ( ssbe ) method for sddes ( [ sddes1 ] ) as follows @xmath18 @xmath19 where @xmath20 and for @xmath21 @xmath22 for arbitrary stepsize @xmath23 , @xmath24 denotes the approximation of @xmath25 at time @xmath26 .. Please generate the next two sentences of the article

we remark that @xmath27 in ( [ y*n ] ) depends on how memory values are handled on non - grid points . generally there are two ways , the first is to use piecewise constant interpolation , corresponding to @xmath28 , and the second to use piecewise linear interpolation . in later development , we prefer to assume @xmath29 to cover both cases . also , we mention that the scheme ( [ ssbe1])-([ssbe2 ] ) here is quite different from the ssbe method in @xcite , which will be explained at the end of this section . in ( [ ssbe1])-([ssbe2 ] ) , @xmath30 serves as an intermediate stage value , and in order to continue the process , we have to solve the implicit equation ( [ ssbe1 ] ) at every step to acquire @xmath30 .

Suppose that you have an abstract for a scientific paper: we develop an approach to liquid thermodynamics based on collective modes . we perform extensive molecular dynamics simulations of noble , molecular and metallic liquids and provide the direct evidence that liquid energy and specific heat are well - described by the temperature dependence of the frenkel ( hopping ) frequency . the agreement between predicted and calculated thermodynamic properties is seen in the notably wide range of temperature spanning tens of thousands of kelvin . the range includes both subcritical liquids and supercritical fluids . we discuss the structural crossover and inter - relationships between structure , dynamics and thermodynamics of liquids and supercritical fluids . . And you have already written the first three sentences of the full article: it is an interesting fact that the liquid state has proven to be difficult to describe by theory throughout the history of condensed matter research @xcite . the problem extends beyond condensed matter and exists in other areas where strong interactions are combined with dynamical disorder such as field theory . in a weakly - interacting system such as a dense gas , the potential energy is much smaller than the kinetic energy .. Please generate the next two sentences of the article

these systems are amenable to perturbation treatment giving corrections to the non - interacting case @xcite . perturbation approaches have been widely explored to calculate liquid thermodynamic properties but have not been able to agree with experiments .

Suppose that you have an abstract for a scientific paper: the combination of a vortex line in a one - dimensional optical lattice with fermions bound to the vortex core makes up an ultracold superstring . we give a detailed derivation of the way to make this supersymmetric string in the laboratory . in particular , we discuss the presence of a fermionic bound state in the vortex core and the tuning of the laser beams needed to achieve supersymmetry . moreover , we discuss experimental consequences of supersymmetry and identify the precise supersymmetry in the problem . finally , we make the mathematical connection with string theory . . And you have already written the first three sentences of the full article: ultracold quantum gases provide a very exciting branch of physics . besides the interesting physics that the gases offer by themselves , it has also been possible in the last few years to model with quantum gases systems from other branches of physics , and by doing so to provide answers to long - standing questions . the latter is mainly due to the amazing accuracy by which their properties can be tuned and manipulated . this involves the trapping potential , the dimensionality , the interaction between the atoms , and the statistics . by using a three - dimensional optical lattice the superfluid - mott insulator transition in the bose - hubbard model. Please generate the next two sentences of the article

has been observed @xcite . bosonic atoms confined in one - dimensional tubes by means of a two - dimensional optical lattice where shown to realize the lieb - liniger gas @xcite .

Suppose that you have an abstract for a scientific paper: the effects of cluster diffusion on the submonolayer island density @xmath0 and island - size distribution @xmath1 ( where @xmath2 is the density of islands of size @xmath3 at coverage @xmath4 ) are studied for the case of irreversible growth of compact islands on a 2d substrate . in our model , we assume instantaneous coalescence of circular islands , while the mobility @xmath5 of an island of size @xmath3 ( where @xmath3 is the number of particles in an island ) satisfies @xmath6 . results are presented for @xmath7 ( corresponding to brownian motion ) , @xmath8 ( corresponding to correlated evaporation - condensation ) , and @xmath9 ( corresponding to cluster diffusion via edge - diffusion ) , as well as for higher values including @xmath10 and @xmath11 . we also compare our results with those obtained in the limit of no cluster mobility ( @xmath12 ) . in general , we find that the exponents @xmath13 and @xmath14 describing the flux - dependence of the island and monomer densities respectively , vary continuously as a function of @xmath15 . similarly , the exponent @xmath16 describing the flux - dependence of the coverage @xmath17 corresponding to the peak island - density also depends continuously on @xmath15 , although the exponent @xmath18 describing the flux - dependence of the coverage corresponding to the peak monomer density does not . in agreement with theoretical predictions that for point - islands with @xmath19 power - law behavior of the island - size distribution ( isd ) is expected , for @xmath20 we find @xmath21 up to a cross - over island - size @xmath22 . however , the value of the exponent @xmath23 obtained in our simulations ( @xmath24 ) is higher than the point - island prediction @xmath25 . similarly , the measured value of the exponent @xmath26 corresponding to the dependence of @xmath22 on the average island - size @xmath27 ( e.g. @xmath28 ) is also significantly higher than the point - island prediction @xmath29 . for @xmath19 , a generalized scaling form for the isd ,.... And you have already written the first three sentences of the full article: recently , there has been a lot of interest in understanding the scaling behavior in submonolayer island nucleation and growth.@xcite one reason for this is that the submonolayer growth regime plays an important role in determining the later stages of thin - film growth.@xcite of particular interest is the dependence of the total island - density @xmath0 and island - size distribution @xmath1 ( where @xmath2 is the density of islands of size @xmath3 at coverage @xmath4 and @xmath3 is the number of monomers in an island ) on deposition parameters such as the deposition flux @xmath36 and growth temperature @xmath37 . one concept that has proven especially useful in studies of submonolayer epitaxial growth is that of a critical island size,@xcite corresponding to one less than the size of the smallest stable " cluster . for example , if we assume that only monomers can diffuse , then in the case of submonolayer growth of 2d islands on a solid 2d substrate , standard nucleation theory@xcite predicts that the peak island density @xmath38 and the monomer density @xmath39 at fixed coverage satisfy , @xmath40 where @xmath41 is the monomer hopping rate , @xmath42 is the critical island size , @xmath43 and @xmath44 . we note that in the case of irreversible island growth ( @xmath45 ) this implies that @xmath46 and @xmath47 .. Please generate the next two sentences of the article

in addition , it has been shown that in the absence of cluster - diffusion and in the pre - coalescence regime the island - size distribution ( isd ) satisfies the scaling form , @xcite @xmath48 where @xmath27 is the average island size , and the scaling function @xmath49 depends on the critical island size.@xcite however , in some cases ( such as in epitaxial growth on metal(111 ) surfaces ) it is also possible for significant _ small _ cluster diffusion to occur.@xcite in addition , several mechanisms for the diffusion of _ large _ clusters on solid surfaces have also been proposed . @xcite in each case , scaling arguments predict that the cluster diffusion coefficient @xmath5 decays as a power - law with island - size @xmath3 ( where @xmath3 is the number of particles in a cluster ) , i.e. @xmath50 .

Suppose that you have an abstract for a scientific paper: there are several physical processes to remove gas from galaxies in clusters , with subsequent starvation and star formation quenching : tidal interactions between galaxies , or tidal stripping from the cluster potential itself , interactions with the hot intra - cluster medium ( icm ) through ram pressure , turbulent or viscous stripping , or also outflows from star formation of nuclear activity , we review the observational evidence for all processes , and numerical simulations of galaxies in clusters which support the respective mechanisms . this allows to compare their relative efficiencies , all along cluster formation . . And you have already written the first three sentences of the full article: among the various possibilities to explain the stripping of matter ( gas and stars ) from galaxies in clusters , the principal actors can be classified in three groups : + 1 . tidal forces : + interaction with a companion , merger : in this case , a correlation between morphological type ( t ) and density ( @xmath0 ) should be expected , ( t-@xmath0 relation ) + interaction with the cluster ; then a correlation between type and radius in the cluster is expected ( t - r relation ) + harassment due to numerous interactions at high velocity and density + 2 . icm - ism interactions : + ram pressure stripping , but also thermal evaporation , turbulent , viscous stripping ; these are purely hydrodynamical mechanisms , and should affect only the diffuse gas .. Please generate the next two sentences of the article

however , they are acting simultaneously with the others , and relative roles are hard to disentangle . since they are efficient only when the cluster is formed , and the icm gathered , have they enough time to act ? or have tides acted before ?

Suppose that you have an abstract for a scientific paper: by proving graph theoretical versions of green - stokes , gauss - bonnet and poincar - hopf , core ideas of undergraduate mathematics can be illustrated in a simple graph theoretical setting . in this pedagogical exposition we present the main proofs on a single page and add illustrations . while discrete stokes is at least 100 years old , the other two results for graphs were found only recently . . And you have already written the first three sentences of the full article: a @xmath0 is a finite set @xmath1 paired with a finite set @xmath2 of unordered pairs @xmath3 with @xmath4 . a simple graph has no multiple connections and no self - loops : every @xmath5 appears only once and no @xmath6 is in @xmath2 . elements in @xmath1 are called , elements in @xmath2 are called . given a simple graph @xmath0 , denote by @xmath7 the of a vertex @xmath8 .. Please generate the next two sentences of the article

it is a subgraph generated by the set of vertices directly connected to @xmath8 . denote by @xmath9 the set of complete @xmath10 subgraphs of @xmath11 .

Suppose that you have an abstract for a scientific paper: ieee 802.15.4 standard is designed for low power and low data rate applications with high reliability . it operates in beacon enable and non - beacon enable modes . in this work , we analyze delay , throughput , load , and end - to - end delay of non - beacon enable mode . analysis of these parameters are performed at varying data rates . evaluation of non beacon enabled mode is done in a 10 node network . we limit our analysis to non beacon or unslotted version because , it performs better than other . protocol performance is examined by changing different medium access control ( mac ) parameters . we consider a full size mac packet with payload size of 114 bytes . in this paper we show that maximum throughput and lowest delay is achieved at highest data rate . ieee 802.15.4 , throughput , delay , end - to - end , load . And you have already written the first three sentences of the full article: during past few years research in areas of wireless ad - hoc networks and wireless sensor networks ( wsns ) are escalated . ieee 802.15.4 is targeted for wireless body area networks ( wbans ) , which requires low power and low data rate applications . invasive computing is term used to describe future of computing and communications [ 1 - 3 ] . due to these concepts , personal and business domains. Please generate the next two sentences of the article

are being densely populated with sensors . one area of increasing interest is the adaptation of technology to operate in and around human body .

Suppose that you have an abstract for a scientific paper: we consider the problem of hypothesis testing in the situation when the first hypothesis is simple and the second one is local one - sided composite . we describe the choice of the thresholds and the power functions of the score function test , of the general likelihood ratio test , of the wald test and of two bayes tests in the situation when the intensity function of the observed inhomogeneous poisson process is smooth with respect to the parameter . it is shown that almost all these tests are asymptotically uniformly most powerful . the results of numerical simulations are presented . msc 2010 classification : 62m02 , 62f03 , 62f05 . _ key words : _ hypothesis testing , inhomogeneous poisson processes , asymptotic theory , composite alternatives , regular situation . . And you have already written the first three sentences of the full article: the hypothesis testing theory is a well developed branch of mathematical statistics @xcite . the asymptotic approach allows to find satisfactory solutions in many different situations . the simplest problems , like the testing of two simple hypotheses , have well known solutions . recall that if we fix the first type error and seek the test which maximizes the power , then we obtain immediately ( by neyman - pearson lemma ) the most powerful test based on the likelihood ratio statistic .. Please generate the next two sentences of the article

the case of composite alternative is more difficult to treat and here the asymptotic solution is available in the regular case . it is possible , using , for example , the score function test ( sft ) , to construct the asymptotically ( locally ) most powerful test .

Suppose that you have an abstract for a scientific paper: measurements of the de haas - van alphen effect have been carried out on the heavy fermion anti - ferromagnet cerhin@xmath0 at temperatures between 25 mk and 500 mk under pressure . we present some preliminary results of our measurements to track the evolution of the fermi surface as the pressure induced superconducting transition is approached . , , , , , de haas - van alphen ; heavy fermions ; superconductivity ; high pressure . And you have already written the first three sentences of the full article: the dimensionality of the 115 materials , cerhin@xmath1 , ceirin@xmath1 , and cecoin@xmath1 , appears to be related to their superconducting transition temperature . the material with the highest t@xmath2 , cecoin@xmath0 , has the most 2d - like fermi surface ( fs ) of the three . @xcite cerhin@xmath0 has a high t@xmath2 ( @xmath32.1 k ) , but only under a pressure of @xmath316 kbar . at ambient pressures ,. Please generate the next two sentences of the article

cerhin@xmath0 is an anti - ferromagnet . the fs of cerhin@xmath0 was the subject of one of our recent publications.@xcite in order to confirm the link between the superconducting state and fs dimensionality , the fs as a function of pressure in cerhin@xmath0 should be measured .

Suppose that you have an abstract for a scientific paper: the study of high energy nuclear collisions has entered a new stage with rhic ; it therefore seems a good time to ask what we have learned from the experimental results obtained up to now . i recall what we had expected to find when the sps and ags programs were started , summarize what actually was found , and then try to assess what we have learned from the results . . And you have already written the first three sentences of the full article: it all began with the idea of an intrinsic limit to hadron thermodynamics . during the past fifty years , different conceptual approaches had led to an ultimate temperature of strongly interacting matter . pomeranchuk @xcite first obtained it from the finite spatial extension of hadrons : a hadron can only have an independent existence if it has an independent volume .. Please generate the next two sentences of the article

then hagedorn @xcite arrived at a limiting temperature by postulating a self - similar hadronic resonance composition : a resonance consists of resonances which consist of resonances , and so on . the resulting excitation spectrum was later also derived in the dual resonance model @xcite . with the advent of the quark infrastructure of hadrons and of quantum chromodynamics , it became clear that the ultimate temperature found in all these considerations was really a transition point to a new state of matter , to a plasma of deconfined quarks and gluons @xcite .

Suppose that you have an abstract for a scientific paper: we demonstrate that gravitationally lensed quasars are easily recognized using image subtraction methods as time variable sources that are spatially extended . for galactic latitudes @xmath0 , lensed quasars dominate the population of spatially extended variable sources , although there is some contamination from variable star pairs , variable star - quasar pairs and binary quasars that can be easily controlled using other information in the survey such as the object light curves and colors . this will allow planned large - scale synoptic surveys to find lensed quasars almost down to their detection limits without the need for extensive follow - up observations . . And you have already written the first three sentences of the full article: in theory , gravitational lenses can be used to address astrophysical problems such as the cosmological model , the structure and evolution of galaxies , and the structure of quasar accretion disks ( see the reviews by kochanek ( @xcite ) of strong lensing and wambsganss ( @xcite ) of microlensing ) . one of the main challenges in using lenses for any of these applications is discovering large numbers of lenses efficiently ( see the review of lens surveys in kochanek ( @xcite ) ) . most known lenses have been found either from optical imaging surveys of known quasars ( see pindor et al .. Please generate the next two sentences of the article

@xcite for a recent study ) , radio imaging surveys of flat - spectrum radio sources ( see browne et al . @xcite ) , or searches for anomalous , higher redshift emission lines in galaxy spectra ( see bolton et al .

Suppose that you have an abstract for a scientific paper: @xmath0-mode of polarized anisotropies of the cosmic microwave background is a unique and nearly direct probe of primordial inflation , which can constrain the amplitude of the primordial gravity waves . however , its detection and precise measurement is made difficult by a minute amplitude of the signal , which has to be discerned from many contributions of non - cosmological origin and reliable estimated in the presence of numerous sources of statistical uncertainties . among these latter , the @xmath1-to-@xmath0 leakage , arising as a result of partial sky coverage , has been found to play a key and potentially fundamental role in determining the possible statistical significance with which the primordial @xmath0-mode signal can be detected . in this work we employ the pure - pseudo formalism devised to minimise the effects of the leakage on the variance of power spectrum estimates and discuss the limits on the tensor - to - scalar ratio , @xmath2 , that could be realistically set by current and forthcoming measurements of the @xmath0-mode angular power spectrum . we compare those with the results obtained using other approaches : nave mode - counting , minimum - variance quadratic estimators , and re - visit the question of optimizing the sky coverage of small - scale , suborbital experiments in order to maximize the statistical significance of the detection of @xmath2 . we show that the optimized sky coverage is largely insensitive to the adopted approach at least for reasonably compact sky patches . we find , however , that the mode - counting overestimates the detection significance by a factor @xmath3 as compared to the lossless maximum variance approach and by a factor @xmath4 as compared to the lossy pure pseudo - spectrum estimator . in a second time , we consider more realistic experimental configurations . with a pure pseudospectrum reconstruction of @xmath0-modes and considering only statistical uncertainties , we find that a detection of @xmath5 , @xmath6 and @xmath7 at 99% of.... And you have already written the first three sentences of the full article: primordial gravity waves are expected to be produced during cosmic inflation in addition to scalar perturbations . if indeed present , they would leave a characteristic footprint on the polarized anisotropies of the cosmic microwave background ( cmb ) , as they are considered to be essentially the sole source of the so - called primordial @xmath0-mode residing at the super - horizon scales at the time of the last scattering . a detection of the @xmath0-mode angular power spectrum at large angular scales would be then treated as a smoking gun of inflation , while a precise measurement of its amplitude would constrain the energy scale of inflation , or , geometrically speaking , the expansion rate of the universe during inflation @xcite .. Please generate the next two sentences of the article

this amplitude is expressed by the tensor - to - scalar ratio , @xmath2 , defined as the relative power of primordial gravity waves with respect to that of the scalar perturbations at some pivot scale @xmath8 , chosen here to be equal to @xmath9 mpc@xmath10 . currently , the most stringent upper bound on @xmath2 using temperature anisotropies has been derived by the planck collaboration : @xmath11 at 95% cl @xcite , while a recent joint analysis of the planck and polarized data set an upper limit @xmath12 at 95% cl @xcite .

Suppose that you have an abstract for a scientific paper: salkuyeh proposed the picard - hss iteration method to solve the absolute value equation ( ave ) , which is a class of non - differentiable np - hard problem . to further improve its performance , a nonlinear hss - like iteration method is proposed . compared to that the picard - hss method is an inner - outer double - layer iteration scheme , the hss - like iteration is only a monolayer and the iteration vector could be updated timely . some numerical experiments are used to demonstrate that the nonlinear hss - like method is feasible , robust and effective . absolute value equation , nonlinear hss - like iteration , fixed point iteration , positive definite 15a06,65f10,65h10 . And you have already written the first three sentences of the full article: the solution of the absolute value equation ( ave ) of the following form is considered : @xmath0 here , @xmath1 , @xmath2 and @xmath3 denotes the component - wise absolute value of vector @xmath4 , i.e. , @xmath5 . the ave ( [ eq:1 ] ) is a special case of the generalized absolute value equation ( gave ) of the type @xmath6 where @xmath7 and @xmath8 . the gave ( [ eq:1a ] ) was introduced in @xcite and investigated in a more general context in @xcite .. Please generate the next two sentences of the article

recently , these problems have been investigated in the literature @xcite . the ave ( [ eq:1 ] ) arises in linear programs , quadratic programs , bimatrix games and other problems , which can all be reduced to a linear complementarity problem ( lcp ) @xcite , and the lcp is equivalent to the ave ( [ eq:1 ] ) .

Suppose that you have an abstract for a scientific paper: we present the current status of cosmic shear studies and their implications on cosmological models . theoretical expectations and observational results are discussed in the framework of standard cosmology and cdm scenarios . the potentials of the next generation cosmic shear surveys are discussed . # 1 . And you have already written the first three sentences of the full article: the gravitational deflection of light beams by large scale structures of the universe ( cosmological lensing ) amplifies and modifies the shape of distant galaxies and quasars . magnification produces correlation between the density of foreground lenses and the apparent luminosity of distant galaxies or quasars ( magnification bias ) , whereas distortion induces a correlation of ellipticity distribution of lensed galaxies ( cosmic shear ) . in both cases , the properties of cosmological lensing signals probe the matter content and the geometry of universe and how perturbations grew and clustered during the past gigayears . + albeit difficult to detect , the recent cosmic shear detections claimed by several groups demonstrate that it is no longer a technical challenge .. Please generate the next two sentences of the article

it is therefore possible to study the universe through a new window which directly probes dark matter instead of light and allows cosmologists to measure cosmological parameters and dark matter power spectrum from weak gravitational distortion . let us assume that the shape of galaxies can be simply characterize by their surface brightness second moments @xmath0 , ( see @xcite , @xcite and references therein ) : @xmath1 because of gravitational lensing , a galaxy with intrinsic ellipticity @xmath2 is measured with an ellipticity @xmath3 , where @xmath4 is the gravitational distortion , @xmath5 @xmath6 and @xmath7 are respectively the gravitational convergence and shear .

Suppose that you have an abstract for a scientific paper: we numerically investigate the excitation and temporal evolution of oscillations in a two - dimensional coronal arcade by including the three - dimensional propagation of perturbations . the time evolution of impulsively generated perturbations is studied by solving the linear , ideal magnetohydrodynamic ( mhd ) equations in the zero-@xmath0 approximation . as we neglect gas pressure the slow mode is absent and therefore only coupled mhd fast and alfvn modes remain . two types of numerical experiments are performed . first , the resonant wave energy transfer between a fast normal mode of the system and local alfvn waves is analyzed . it is seen how , because of resonant coupling , the fast wave with global character transfers its energy to alfvnic oscillations localized around a particular magnetic surface within the arcade , thus producing the damping of the initial fast mhd mode . second , the time evolution of a localized impulsive excitation , trying to mimic a nearby coronal disturbance , is considered . in this case , the generated fast wavefront leaves its energy on several magnetic surfaces within the arcade . the system is therefore able to trap energy in the form of alfvnic oscillations , even in the absence of a density enhancement such as that of a coronal loop . these local oscillations are subsequently phase - mixed to smaller spatial scales . the amount of wave energy trapped by the system via wave energy conversion strongly depends on the wavelength of perturbations in the perpendicular direction , but is almost independent from the ratio of the magnetic to density scale heights . . And you have already written the first three sentences of the full article: the presence of waves and oscillations in the solar corona is a well known feature that has been observed for long time . for an overview of the early observational background see @xcite . nowadays , because of the increasing spatial and temporal resolution of the euv instruments onboard trace , soho and hinode spacecraft , accurate observations of oscillations in different coronal structures are accomplished . many authors have reported observations of transversal coronal loop oscillations from both ground and space - based instruments @xcite . when these observations are compared with theoretical models @xcite ,. Please generate the next two sentences of the article

the possibility of inferring some plasma parameters , otherwise difficult to measure , and of improving the existing theoretical models is open ; see @xcite for a review . magnetohydrodynamics ( mhd ) is the underlying theory of coronal seismology and it is believed that all these observed oscillations and waves can be interpreted theoretically in terms of mhd modes of different coronal plasma structures .

Suppose that you have an abstract for a scientific paper: the social connections people form online affect the quality of information they receive and their online experience . although a host of socioeconomic and cognitive factors were implicated in the formation of offline social ties , few of them have been empirically validated , particularly in an online setting . in this study , we analyze a large corpus of geo - referenced messages , or tweets , posted by social media users from a major us metropolitan area . we linked these tweets to us census data through their locations . this allowed us to measure emotions expressed in the tweets posted from an area , the structure of social connections , and also use that area s socioeconomic characteristics in analysis . we find that at an aggregate level , places where social media users engage more deeply with less diverse social contacts are those where they express more negative emotions , like sadness and anger . demographics also has an impact : these places have residents with lower household income and education levels . conversely , places where people engage less frequently but with diverse contacts have happier , more positive messages posted from them and also have better educated , younger , more affluent residents . results suggest that cognitive factors and offline characteristics affect the quality of online interactions . our work highlights the value of linking social media data to traditional data sources , such as us census , to drive novel analysis of online behavior . . And you have already written the first three sentences of the full article: humans have evolved large brains , in part to handle the cognitive demands of social relationships @xcite . the social structures resulting from these relationships confer numerous fitness advantages . scholars distinguish between two types of social relationships : those representing strong and weak ties .. Please generate the next two sentences of the article

strong ties are characterized by high frequency of interaction and emotional intimacy that can be found in relationships between family members or close friends . people connected by strong ties share mutual friends @xcite , forming cohesive social bonds that are essential for providing emotional and material support @xcite and creating resilient communities @xcite .

Suppose that you have an abstract for a scientific paper: we present a detailed analysis of the ionisation state and heavy element abundances in the intergalactic medium ( igm ) . the civ doublet is shown by 30 % of the 182 selected optically thin clouds in 10 qso lines of sight . direct metallicy calculations have been performed on individual systems with detected civ and siiv ( 10% of the sample ) varying the uv photoionising source , cloud density and size and silicon relative abundance . the best solutions for carbon content in this subsample ( redshift coverage @xmath0 ) span between 1/6 and 1/300 of the solar value with no evidence of redshift evolution in both the metallicity and the ionising source . global properties of the whole sample indicate that the metallicity in clouds with civ and siiv is not typical of the igm . the redshift evolution of the uvb is one of the possible sources of the observed siiv / civ trend presented by cowie and collaborators during this meeting . future detection of heavy elements in lower hi column density ( @xmath1 ) clouds relies on the presence of ovi and nv at @xmath2 . . And you have already written the first three sentences of the full article: for many years the forest has been considered a different class of objects with respect to galaxies . the available sensitivity was too low to detect any sign of non primordial composition in the intergalactic gas clouds at high redshift . thanks to the advent of high resolution and signal to noise spectroscopy , the old idea on the majority of quasar absorption lines has been revisited and opened in the last few years a still pending debate on the connection between the forest and the galaxy formation of the early universe .. Please generate the next two sentences of the article

the detection of ions different from civ in optically thin clouds is made complicated by harder observational conditions , whereas the still too poor knowledge of the ionisation mechanisms which determine the ion abundances in those clouds has often discouraged attempts of metal content estimations as a function of redshift and of hi column density . however abundance investigation of the clouds has fundamental implications in the understanding of the enrichment processes in the igm by pop iii stars in the @xmath3 universe .

Suppose that you have an abstract for a scientific paper: content delivery success in wireless caching helper networks depends mainly on cache - based channel selection diversity and network interference . for given channel fading and network geometry , both channel selection diversity and network interference dynamically vary according to what and how the caching helpers cache at their finite storage space . we study probabilistic content placement ( or caching placement ) to desirably control cache - based channel selection diversity and network interference in a stochastic wireless caching helper network , with sophisticated considerations of wireless fading channels , interactions among multiple users such as interference and loads at caching helpers , and arbitrary memory size . using stochastic geometry , we derive optimal caching probabilities in closed form to maximize the average success probability of content delivery and propose an efficient algorithm to find the solution in a noise - limited network . in an interference - limited network , based on a lower bound of the average success probability of content delivery , we find near - optimal caching probabilities in closed form to control the channel selection diversity and the network interference . we numerically verify that the proposed content placement is superior to other comparable content placement strategies . probabilistic content placement , caching probability , stochastic geometry , channel selection diversity . And you have already written the first three sentences of the full article: recent evolution of mobile devices such as smart - phones and tablets has facilitated access to multi - media contents anytime and anywhere but such devices result in an explosive data traffic increase . the cisco expects by 2019 that these traffic demands will be grown up to 24.3 exabytes per month and the mobile video streaming traffic will occupy almost 72% of the entire data traffic @xcite . interestingly , numerous popular contents are asynchronously but repeatedly requested by many users and thus substantial amounts of data traffic have been redundantly generated over networks @xcite .. Please generate the next two sentences of the article

motivated by this , caching or pre - fetching some popular video contents at the network edge such as mobile hand - held devices or small cells ( termed as _ local caching _ ) has been considered as a promising technique to alleviate the network traffic load . as the cache - enabled edge node plays a similar role as a local proxy server with a small cache memory size , the local wireless caching has the advantages of i ) reducing the burden of the backhaul by avoiding the repeated transmission of the same contents from the core network to end - users and ii ) reducing latency by shortening the communication distance . in recent years

Suppose that you have an abstract for a scientific paper: a coamoeba is the image of a subvariety of a complex torus under the argument map to the real torus . we describe the structure of the boundary of the coamoeba of a variety , which we relate to its logarithmic limit set . detailed examples of lines in three - dimensional space illustrate and motivate these results . . And you have already written the first three sentences of the full article: a coamoeba is the image of a subvariety of a complex torus under the argument map to the real torus . coamoebae are cousins to amoebae , which are images of subvarieties under the coordinatewise logarithm map @xmath0 . amoebae were introduced by gelfand , kapranov , and zelevinsky in 1994 @xcite , and have subsequently been widely studied @xcite .. Please generate the next two sentences of the article

coamoebae were introduced by passare in a talk in 2004 , and they appear to have many beautiful and interesting properties . for example , coamoebae of @xmath1-discriminants in dimension two are unions of two non - convex polyhedra @xcite , and a hypersurface coamoeba has an associated arrangement of codimension one tori contained in its closure @xcite .

Suppose that you have an abstract for a scientific paper: we first show that a large amount of metal - poor gas is stripped from the small magellanic cloud ( smc ) and fallen into the large magellanic cloud ( lmc ) during the tidal interaction between the smc , the lmc , and the galaxy over the last 2 gyrs . we propose that this metal - poor gas can closely be associated with the origin of lmc s young and intermediate - age stars and star clusters with distinctively low - metallicities with [ fe / h ] @xmath0 . we numerically investigate whether gas initially in the outer part of the smc s gas disk can be stripped during the lmc - smc - galaxy interaction and consequently can pass through the central region ( @xmath1 kpc ) of the lmc . we find that about 0.7 % and 18 % of the smc s gas can pass through the central region of the lmc about 1.3 gyr ago and 0.2 gyr ago , respectively . the possible mean metallicity of the replenished gas from the smc to lmc is about [ fe / h ] = -0.9 to -1.0 for the two interacting phases . these results imply that the lmc can temporarily replenish gas supplies through the sporadic accretion and infall of metal - poor gas from the smc . these furthermore imply that if these gas from the smc can collide with gas in the lmc to form new stars in the lmc , the metallicities of the stars can be significantly lower than those of stars formed from gas initially within the lmc . [ firstpage ] magellanic clouds galaxies : structure galaxies : kinematics and dynamics galaxies : halos galaxies : star clusters . And you have already written the first three sentences of the full article: tidal interaction between the lmc , the smc , and the galaxy have long been considered to play vital roles not only in dynamical and chemical evolution of the magellanic clouds ( mcs ) but also in the formation of the magellanic stream ( ms ) and bridge ( mb ) around the galaxy ( e.g. , westerland 1999 ; murai & fujimoto 1981 ; bekki & chiba 2005 , b05 ) . although previous theoretical and numerical studies on the lmc - smc - galaxy tidal interaction discussed extensively the origin of dynamical properties of the mb ( e.g. , gardiner & noguchi 1995 , g96 ) , they have not yet investigated so extensively the long - term formation histories of field stars and star clusters ( scs ) in the mcs . therefore , long - standing and remarkable problems related to the interplay between the lmc - smc - galaxy interaction and the formation histories of stars and scs remain unsolved ( see bekki et al . 2004a , b for the first attempts to challenge these problems ) . one of intriguing and unexplained observations on scs in the lmc is that an intermediate - age sc ( ngc 1718 ) with the estimated age of @xmath2 gyr has a distinctively low metallicity of [ fe / h]@xmath3 among intermediate - age scs ( geisler et al .. Please generate the next two sentences of the article

2003 , g03 ; grocholski et al . 2006 , g06 ) .

Suppose that you have an abstract for a scientific paper: we present simulations of triton s post - capture orbit that confirm the importance of kozai - type oscillations in its orbital elements . in the context of the tidal orbital evolution model , these variations require average pericenter distances much higher than previously published , and the timescale for the tidal orbital evolution of triton becomes longer than the age of the solar system . recently - discovered irregular satellites present a new constraint on triton s orbital history . our numerical integrations of test particles indicate a timescale for triton s orbital evolution to be less than @xmath0 yrs for a reasonable number of distant satellites to survive triton s passage . this timescale is inconsistent with the exclusively tidal evolution ( time scale of @xmath1 yrs ) , but consistent with the interestion with the debris from satellite - satellite collisions . any major regular satellites will quickly collide among themselves after being perturbed by triton , and the resulting debris disk would eventually be swept up by triton ; given that the total mass of the uranian satellite system is 40% of that of triton , large scale evolution is possible . this scenario could have followed either collisional or the recently - discussed three - body - interaction - based capture . . And you have already written the first three sentences of the full article: neptune s triton is the only large planetary satellite to orbit retrograde relative to the planet s rotation . @xcite and later @xcite suggested that triton is a captured satellite , whose originally eccentric orbit was circularized due to tidal dissipation within triton . @xcite postulate that triton was captured from heliocentric orbit by a collision with a pre - existing satellite , and its initial high - eccentricity orbit then evolved due to tidal dissipation alone . they showed that the tidal evolution timescale is significantly shorter than the age of the solar system ( a few times @xmath2 years ) , even when the variations in triton s eccentricity with @xmath3-yr period are accounted for .. Please generate the next two sentences of the article

however , @xcite noted that the criteria for non - disruptive capture are much stricter than @xcite calculated . if the original regular satellites of neptune and uranus were similar , a collision with the largest moons ( preferred due to their cross - sections ) would disrupt triton , with re - accretion on an orbit inclined to neptune s equator being impossible . @xcite suggested instead that triton was captured and its orbit was evolved by aerodynamic drag in neptune s primordial protosatellite nebula , and that after its orbit ewas circularized triton s gravity would be sufficient to clear a disk gap and thus halt further evolution .

Suppose that you have an abstract for a scientific paper: the akari and spitzer satellites provided an unique opportunity to observe a variety of stars , which are considered as departing from the asymptotic giant branch ( agb ) and have started their post - agb evolution recently . most of these stars are absent optically and are bright in the mid - ir wavelength range . spectra of close to 200 objects have been obtained . for all of them the @xmath0 m spectral energy distribution has been constructed using photometric data from various surveys . we report here on the results of spitzer observations of 88 iras selected post - agb candidates and discuss them in comparison to the results of the akari observations of post - agb candidates reported elsewhere in these proceedings . the dust compositions can be divided broadly in oxygen- and carbon - rich types , but a variety of intermediate types have been found . among the oxygen - rich stars amorphous dust prevails , but a few sources show emission features from crystalline dust . the spectra from carbon - rich shells may be completely featureless , may show emission features from pahs or a molecular absorption line from c@xmath1h@xmath1 . we found also sources with a neon emission line at @xmath2 m . more than a third of all sources show a near - infrared excess at @xmath3 m and almost all of them show evidence of c - rich dust in their shells . we postulate that the emerging post - agb wind after the end of agb evolution contains always carbon - rich dust irrespective of the chemistry of the former agb star . . And you have already written the first three sentences of the full article: at the end of the stellar evolution on the asymptotic giant branch ( agb ) stars loose copious amounts of mass , which build up a circumstellar dust and gas shell hiding the star from optical view almost completely . stars departing from the agb and evolving towards the planetary nebula ( pn ) phase are therefore difficult to observe optically . it was found that a number of proto - planetary nebulae ( cf . in crl 2688 ; @xcite @xcite ) show high velocity bipolar outflows which are connected to a fast , axially - symmetric wind , which is taking the place of the much slower , spherically - symmetric wind operating on the agb .. Please generate the next two sentences of the article

the physical mechanism responsible for the change of the spherically - symmetric to an axially - symmetric , or in some cases point - symmetric wind is strongly debated . observations of masers in transition objects often reveal that this morphological change takes place at a very early stage in the post - agb phase ( @xcite @xcite ; @xcite @xcite ) , while the star is still heavily obscured in the optical range .

Suppose that you have an abstract for a scientific paper: this paper continues a study initiated in @xcite , on the localization transition of a lattice free field on @xmath0 interacting with a quenched disordered substrate that acts on the interface when its height is close to zero . the substrate has the tendency to localize or repel the interface at different sites . a transition takes place when the average pinning potential @xmath1 goes past a threshold @xmath2 : from a delocalized phase @xmath3 , where the field is macroscopically repelled by the substrate to a localized one @xmath4 where the field sticks to the substrate . our goal is to investigate the effect of the presence of disorder on this phase transition . we focus on the two dimensional case @xmath5 for which we had obtained so far only limited results . we prove that the value of @xmath6 is the same as for the annealed model , for all values of @xmath7 and that in a neighborhood of @xmath2 . moreover we prove that , in contrast with the case @xmath8 where the free energy has a quadratic behavior near the critical point , the phase transition is of infinite order @xmath9 + 2010 _ mathematics subject classification : 60k35 , 60k37 , 82b27 , 82b44 _ + _ keywords : lattice gaussian free field , disordered pinning model , localization transition , critical behavior , disorder relevance , co - membrane model _ . And you have already written the first three sentences of the full article: the aim of statistical mechanics is to obtain a qualitative understanding of natural phenomena of phase transitions by the study of simplified models , often built on a lattices . in general the hamiltonian of a model of statistical mechanics is left invariant by the lattice symmetries : a prototypical example being the ising model describing a ferromagnet . however , one might argue that materials which are found in nature are usually not completely homogeneous and for this reason , physicists where led to considering systems in which the interaction terms , for example the potentials between nearest neighbor spins , are chosen by sampling a random field which we call _ disorder _ with good ergodic properties , often even a field of independent identically distributed random variables .. Please generate the next two sentences of the article

an important question which arises is thus whether the results concerning the phase transition obtained for a model with homogeneous interactions referred to as _ the pure system _ ( e.g. the onsager solution of the two dimensional ising model ) remain valid when a system where randomness of a very small amplitude is introduced . in @xcite a. b. harris , gave a strikingly simple heuristical argument , based on renormalization theory consideration , to predict the effect of the introduction of a small amount of the system : in substance harris criterion predict that if the phase transition of the pure system is sufficiently smooth , it will not be affected by small perturbation ( disorder is then said to be _ irrelevant _ ) , while in the other cases the behavior of the system is affected by an arbitrary small addition of randomness ( disorder is _ relevant _ ) . to be complete ,

Suppose that you have an abstract for a scientific paper: we propose the concept of a terahertz ( thz ) uncooled bolometer based on n - type and p - type graphene layers ( gls ) , constituting the absorbing regions , connected by an array of undoped graphene nanoribbons ( gnrs ) . the gls absorb the thz radiation with the gnr array playing the role of the barrier region ( resulting in ngl - gnr - pgl bolometer ) . the absorption of the incident thz radiation in the gl n- and p- regions leads to variations of the effective temperature of electrons and holes and of their fermi energy resulting in the variation of the current through the gnrs . using the proposed device model , we calculate the dark current and the bolometer responsivity as functions of the gnr energy gap , applied voltage , and the thz frequency . we demonstrate that the proposed bolometer can surpass the hot - electron bolometers using traditional semiconductor heterostructures . . And you have already written the first three sentences of the full article: owing to the gapless energy spectrum @xcite , graphene layers ( gls ) absorb electromagnetic radiation in a wide spectral range ( from the ultraviolet to terahertz ) due to the interband transitions @xcite . therefore , gls can be used in photodetectors , light sources , modulators , and mixers using the interband transitions @xcite . the performance of these devices can be enhanced by utilizing multiple - gl structures @xcite . for the infrared and visible spectral ranges ,. Please generate the next two sentences of the article

the interband absorption prevails over the intraband ( drude ) absorption . however , in the terahertz ( thz ) range , especially at low thz frequencies , the drude absorption can dominate .

Suppose that you have an abstract for a scientific paper: energies of @xmath0 ( @xmath1 ) and @xmath2 states in neutral ag and ag - like ions with nuclear charges @xmath3 are calculated using relativistic many - body perturbation theory . reduced matrix elements , oscillator strengths , transition rates and lifetimes are calculated for the 17 possible @xmath4 and @xmath5 electric - dipole transitions . third - order corrections to energies and dipole matrix elements are included for neutral ag and for ions with @xmath6 . second - order corrections are included for @xmath7 . comparisons are made with available experimental data for transition energies and lifetimes . correlation energies and transition rates are shown graphically as functions of nuclear charge @xmath8 for selected cases . these calculations provide a theoretical benchmark for comparison with experiment and theory . . And you have already written the first three sentences of the full article: this work continues earlier third - order relativistic many - body perturbation theory ( rmbpt ) studies of energy levels of ions with one valence electron outside a closed core . in refs . @xcite third - order rmbpt was used to calculate energies of the three lowest states ( @xmath9 , @xmath10 , and @xmath11 ) in li- , na- , and cu - like ions along the respective isoelectronic sequences , while in the present work , third - order rmbpt is used to calculate energies of the eleven lowest levels , @xmath12 , @xmath13 , @xmath14 , @xmath2 , @xmath15 , and @xmath16 in ag - like ions . it should be noted that the @xmath17 cores of li- , na- , and cu - like ions are completely filled , by contrast with ag - like ions , where the @xmath18 core [ cu@xmath19@xmath20 is incomplete .. Please generate the next two sentences of the article

third - order rmbpt calculations of @xmath21 transition amplitudes in ag - like ions up to @xmath8=60 were previously performed by @xcite . in the present paper , we extend the calculations of @xcite to obtain energies , reduced matrix elements , oscillator strengths , and transition rates for the 17 possible @xmath4 and @xmath5 e1 transitions . additionally , we evaluate lifetimes of excited states .

Suppose that you have an abstract for a scientific paper: although some of the properties of the caustics in planetary microlensing have been known , our understanding of them is mostly from scattered information based on numerical approaches . in this paper , we conduct a comprehensive and analytic analysis of the properties of the planetary caustics , which are one of the two sets of caustics in planetary microlensing , those located away from the central star . under the perturbative approximation , we derive analytic expressions for the location , size , and shape of the planetary caustic as a function of the star - planet separation and the planet / star mass ratio . based on these expressions combined with those for the central caustic , which is the other set of caustics located close to the central star , we compare the similarities and differences between the planetary and central caustics . we also present the expressions for the size ratio between the two types of caustics and for the condition of the merging of the two types of caustics . these analytic expressions will be useful in understanding the dependence of the planetary lensing behavior on the planet parameters and thus in interpreting the planetary lensing signals . . And you have already written the first three sentences of the full article: microlensing is one of the most powerful methods that can be used to search for extrasolar planets @xcite . recently , two robust microlensing detections of exoplanets were reported by @xcite and @xcite . the signal of a planetary companion to microlens stars is a short - duration perturbation to the smooth standard light curve of the primary - induced lensing event occurring on a background source star .. Please generate the next two sentences of the article

the planetary perturbation occurs when the source star passes close to the caustic . the caustic represents the set of source positions at which the magnification of a point source becomes infinite .

Suppose that you have an abstract for a scientific paper: we report on _ nustar _ , _ xmm - newton _ and _ swift _ observations of the gamma - ray binary 1fgl j1018.6@xmath05856 . we measure the orbital period to be @xmath1 days using _ swift _ data spanning 1900 days . the orbital period is different from the 2011 gamma - ray measurement which was used in the previous x - ray study of @xcite using @xmath2400days of _ swift _ data , but is consistent with a new gamma - ray solution reported in 2014 . the light curve folded on the new period is qualitatively similar to that reported previously , having a spike at phase 0 and broad sinusoidal modulation . the x - ray flux enhancement at phase 0 occurs more regularly in time than was previously suggested . a spiky structure at this phase seems to be a persistent feature , although there is some variability . furthermore , we find that the source flux clearly correlates with the spectral hardness throughout all orbital phases , and that the broadband x - ray spectra measured with _ nustar _ , _ xmm - newton _ , and _ swift _ are well fit with an unbroken power - law model . this spectrum suggests that the system may not be accretion - powered . . And you have already written the first three sentences of the full article: gamma - ray binaries are systems composed of a massive star and a compact object and from which persistent gev and/or tev gamma - ray emission is detected and dominates the overall non - thermal spectrum . they emit across the electromagnetic spectrum from the radio to tev gamma ray ( see * ? ? ? * for a review ) . there are only five gamma - ray binaries known to date @xcite , and only for one source has the compact object been identified ( psr b1259@xmath063 ; * ? ? ?. Please generate the next two sentences of the article

since most of the energy output of a gamma - ray binary is in the gamma - ray band , current theoretical studies focus on explaining the high energy emission properties . the gamma - ray emission models can be categorized into two classes : microquasar models ( e.g. , * ? ? ?

Suppose that you have an abstract for a scientific paper: searching for the ultra high energy cosmic rays and neutrinos of @xmath0 is of great cosmological importance . a powerful technique is to search for the erenkov radio emission caused by uhecr or uhe neutrinos impinging on the lunar regolith . we examine in this paper feasibility of detecting these events by observing with the giant metrewave radio telescope ( gmrt ) which has a large collecting area and operates over a wide frequency range with an orthogonal polarisation capability . we discuss here prospects of observations of the erenkov radio emission with the gmrt at 140 mhz with 32 mhz bandwidth using the incoherent array and also forming 25 beams of the central array ( effective collecting area of 14250 @xmath1 ) to cover the moon . we also consider using the ooty radio telescope ( ort ) which was specially designed in 1970 for tracking the moon . the ort consists of a 530 m long and 30 m wide parabolic cylinder that is placed in the north south direction on a hill with the same slope as the latitude of the station . thus it becomes possible to track the moon for 9.5 hours on a given day by a simple rotation along the long axis of the parabolic cylinder . ort operates at 325 mhz and has an effective collecting area of @xmath2 8000 @xmath3 recently a digital system has been installed by scientists of the raman research institute ( rri ) , bangalore and the radio astronomy centre ( rac ) of ncra / tifr , at ooty allowing a bandwidth of 10 mhz with @xmath2 40 ns sampling . it is possible to form 6 beams covering the moon and 7th beam far away for discrimination of any terrestrial rfi . increasing the bandwidth of the existing 12 beam analogue system of the ort from 4 mhz to 15 mhz to be sampled digitally is planned . it is shown that by observing the moon for @xmath4 1000 hrs using the ort it will provide appreciably higher sensitivity than past searches made elsewhere and also compared to the search being made currently in netherlands using the westerbork synthesis radio telescope (.... And you have already written the first three sentences of the full article: several theoretical predictions and scenarios have been proposed for the existence of ultra high energy ( uhe ) cosmic rays ( uhecr ) and uhe neutrinos @xmath5 detection of the uhecr and particularly uhe neutrinos would be of great importance for understanding the energy of powerful agns , gamma ray bursts and possible existence of massive particles predicted by the gut theories . for detecting uhecr and uhen several ambitious terrestrial experiments are being carried out and also planned with very large collecting areas @xmath6 1 @xmath7 and volumes @xmath6 1 @xmath8 @xcite . askaryan noted in 1960s @xcite , that electromagnetic cascades in dense medium by the uhe particles will develop an excess of negative charge giving rise to incoherent erenkov radiation .. Please generate the next two sentences of the article

later , dagkesamanski and zheleznykh @xcite noted that uhe particles impinging on the lunar regolith at @xmath9 10 m-20 m deep layers of the moon will give rise to radio pulses of nanosecond ( ns ) durations . the large surface area of the moon effectively provides a large surface area for detection of the rare uhe particles .

Suppose that you have an abstract for a scientific paper: we examine a new multiverse scenario in which the component universes interact . we focus our attention to the process of true " vacuum nucleation in the false vacuum within one single element of the multiverse . it is shown that the interactions lead to a collective behaviour that might lead , under specific conditions , to a pre - inflationary phase and ensued distinguishable imprints in the comic microwave background radiation . . And you have already written the first three sentences of the full article: the idea that our universe is an element in a vast set of universes , the multiverse , has been argued to be an interesting way to address the cosmological constant problem in the context of string theory @xcite . of course , this scenario raises many questions . how is the vacuum of our world chosen ? through anthropic arguments @xcite ?. Please generate the next two sentences of the article

through quantum cosmology arguments @xcite ? is the string landscape scenario compatible with predictability @xcite ? do the universes of the multiverse interact @xcite ( see also ref .

Suppose that you have an abstract for a scientific paper: mesoscopic hydrodynamic equations are solved to investigate the dynamics of nanodroplets positioned near a topographic step of the supporting substrate . our results show that the dynamics depends on the characteristic length scales of the system given by the height of the step and the size of the nanodroplets as well as on the constituting substances of both the nanodroplets and the substrate . the lateral motion of nanodroplets far from the step can be described well in terms of a power law of the distance from the step . in general the direction of the motion depends on the details of the effective laterally varying intermolecular forces . but for nanodroplets positioned far from the step it is solely given by the sign of the hamaker constant of the system . moreover , our study reveals that the steps always act as a barrier for transporting liquid droplets from one side of the step to the other . . And you have already written the first three sentences of the full article: understanding the wetting behavior of liquids on solid substrates @xcite is a prerequisite for making use of a myriad of biological and technological applications such as eye irrigation , cell adhesion , tertiary oil recovery , coating , lubrication , paper industry , micro - mechanical devices , and the production of integrated circuits . generically , the solid surfaces in the above mentioned examples are not ideal in the sense that they are neither smooth nor homogeneous . most surfaces are topographically or chemically heterogeneous .. Please generate the next two sentences of the article

such heterogeneities may substantially change the wetting behavior of these surfaces @xcite , which is not necessarily detrimental with respect to envisaged applications . certain topographically structured surfaces are superhydrophobic or superhydrophilic . in the first case droplets roll off these substrates ( instead of flowing ) ,

Suppose that you have an abstract for a scientific paper: we investigate the use of the multiple optimised parameter estimation and data compression algorithm ( moped ) for data compression and faster evaluation of likelihood functions . since moped only guarantees maintaining the fisher matrix of the likelihood at a chosen point , multimodal and some degenerate distributions will present a problem . we present examples of scenarios in which moped does faithfully represent the true likelihood but also cases in which it does not . through these examples , we aim to define a set of criteria for which moped will accurately represent the likelihood and hence may be used to obtain a significant reduction in the time needed to calculate it . these criteria may involve the evaluation of the full likelihood function for comparison . [ firstpage ] methods : data analysis methods : statistical . And you have already written the first three sentences of the full article: multiple optimised parameter estimation and data compression ( moped ; @xcite ) is a patented algorithm for the compression of data and the speeding up of the evaluation of likelihood functions in astronomical data analysis and beyond . it becomes particularly useful when the noise covariance matrix is dependent upon the parameters of the model and so must be calculated and inverted at each likelihood evaluation . however , such benefits come with limitations . since moped only guarantees maintaining the fisher matrix of the likelihood at a chosen point , multimodal and some degenerate distributions will present a problem . in this paper we report on some of the limitations of the application of the moped algorithm . in the cases where moped does accurately represent the likelihood function. Please generate the next two sentences of the article

, however , its compression of the data and consequent much faster likelihood evaluation does provide orders of magnitude improvement in runtime . in @xcite , the authors demonstrate the method by analysing the spectra of galaxies and in @xcite they illustrate the benefits of moped for estimation of the cmb power spectrum .

Suppose that you have an abstract for a scientific paper: due to its proximity , the mass of the supermassive black hole in the nucleus of andromeda galaxy ( m31 ) , the most massive black hole in the local group of galaxies , has been measured by several methods involving the kinematics of a stellar disk that surrounds it . we report here the discovery of an eccentric h@xmath0 emitting disk around the black hole at the center of m31 and show how modeling this disk can provide an independent determination of the mass of the black hole . our model implies a mass of @xmath1 for the central black hole , consistent with the average of determinations by methods involving stellar dynamics , and compatible ( at 1@xmath2 level ) with measurements obtained from the most detailed models of the stellar disk around the central black hole . this value is also consistent with the @xmath3 relation . in order to make a comparison , we applied our simulation on the stellar kinematics in the nucleus of m31 and concluded that the parameters obtained for the stellar disk are not formally compatible with the parameters obtained for the h@xmath0 emitting disk . this result suggests that the stellar and the h@xmath0 emitting disks are intrinsically different from each other . a plausible explanation is that the h@xmath0 emission is associated with a gaseous disk . this hypothesis is supported by the detection of traces of weaker nebular lines in the nuclear region of m31 . however , we can not exclude the possibility that the h@xmath0 emission is , at least partially , generated by stars . . And you have already written the first three sentences of the full article: all massive galaxies appear to host a supermassive black hole ( with @xmath4 ) at their center @xcite . measuring the mass of central black holes in galaxies is of great importance , as the discovery of a relationship between mass and the velocity dispersion of the stars in the central bulge , the @xmath3 relation @xcite , reveals the possible co - evolution of black holes and their host galaxies @xcite . m31 , the andromeda galaxy , is an sb galaxy at a distance of 778 kpc and its nucleus can be observed with excellent spatial resolutions . @xcite , using data obtained with the stratoscope ii , revealed an asymmetry in the nuclear region of m31 , as the bright nucleus did not coincide with either the center of the bulge or the maximum of the stellar velocity dispersion .. Please generate the next two sentences of the article

however , @xcite , using observations from the _ hubble space telescope _ ( _ hst _ ) , showed that the galaxy possesses a double nucleus , the two components being called p1 ( the brightest one ) and p2 ( located , approximately , at the center of the bulge ) . these two components are separated by about @xmath5 .

Suppose that you have an abstract for a scientific paper: recent literature on the aharonov - bohm effect has raised fundamental questions on the classical correspondence of this effect and the physical reality of the electromagnetic potentials in quantum mechanics . reappraisal on feynman s approach to the classical limit of ab effect is presented . the critique throws light on the significance of quantum interference and quantum phase shifts in any such classical correspondence . detailed analysis shows that feynman arguments are untenable on physical grounds and the claim made in the original ab paper that this effect had no classical analog seems valid . the importance of nonintegrable phase factor distinct from the ab phase factor , here termed as fock - london - weyl phase factor for the historical reasons , is underlined in connection with the classical aspects / limits . a topological approach incorporating the physical significance of the interaction field momentum is proposed . a new idea emerges from this approach that attributes the origin of the ab effect to the exchange of modular angular momentum . . And you have already written the first three sentences of the full article: recently conceptual issues of fundamental physical significance have been raised on the aharonov - bohm ( ab ) effect @xcite . nonlocality and/or independent physical reality of the electromagnetic potentials seemingly implied by the ab effect have been questioned and debated in the recent literature @xcite . the original paper on the ab effect @xcite is written with remarkable clarity ; to get proper perspective on the current controversy it would be appropriate to emphasize salient features contained in this article following recent historical account @xcite and theoretical study on gauge invariance @xcite .. Please generate the next two sentences of the article

arbitrariness in choosing the potentials in classical electrodynamics embodied in the gauge transformation @xmath0 and the consequent invariance of the lorentz - maxwell theory unambiguously demonstrate the fact that the potentials are just auxiliary mathematical tools in the classical theory . the principle of gauge invariance in quantum mechanics acquires new significance first recognized by fock in 1926 @xcite since the schroedinger wave function of the charged particle , let us assume it to be electron , gets multiplied by a local phase factor @xmath1 though the potentials are needed in canonical formalism of the classical theory they do not appear in the equation of motion ; in contrast , the electromagnetic potentials can not be eliminated in quantum theory of electron interacting with the electromagnetic fields .

Suppose that you have an abstract for a scientific paper: motivated by recent scanning tunneling and photoemission spectroscopy measurements on self - organized gold chains on a germanium surface we reinvestigate the local single - particle spectral properties of luttinger liquids . in the first part we use the bosonization approach to exactly compute the local spectral function of a simplified field theoretical low - energy model and take a closer look at scaling properties as a function of the ratio of energy and temperature . translational invariant luttinger liquids as well as those with an open boundary ( cut chain geometry ) are considered . we explicitly show that the scaling functions of both setups have the same analytic form . the scaling behavior suggests a variety of consistency checks which can be performed on measured data to experimentally verify luttinger liquid behavior . in a second part we approximately compute the local spectral function of a microscopic lattice model the extended hubbard model close to an open boundary using the functional renormalization group . we show that as a function of energy and temperature it follows the field theoretical prediction in the low - energy regime and point out the importance of nonuniversal energy scales inherent to any microscopic model . the spatial dependence of this spectral function is characterized by oscillatory behavior and an envelope function which follows a power law both in accordance with the field theoretical continuum model . interestingly , for the lattice model we find a phase shift which is proportional to the two - particle interaction and not accounted for in the standard bosonization approach to luttinger liquids with an open boundary . we briefly comment on the effects of several one - dimensional branches cutting the fermi energy and rashba spin - orbit interaction . . And you have already written the first three sentences of the full article: over decades theoretical studies of the single - particle spectral properties of metallic one - dimensional ( 1d ) correlated electron systems so - called luttinger liquids ( lls)were ahead of the experimental attempts to find or synthesize appropriate quasi 1d materials and perform spectroscopy on them . in fact , while at the begining of the 1990 s a clear picture of the basic spectroscopic properties of translational invariant lls was established ( for reviews see e.g. refs . @xcite , @xcite and @xcite ) this period witnessed the first serious attempts to experimentally verify the specific spectroscopic signatures of lls @xcite . these are the ( i ) low - energy power - law suppression of the local spectral function @xmath0 for energies @xmath1 close to the chemical potential @xcite with @xmath2 depending on the two - particle interaction as well as ( ii ) the appearance of two dispersing features in the momentum resolved spectral function @xmath3 ( spin - charge separation ) @xcite instead of a single quasi - particle peak of a fermi liquid . for finite temperatures @xmath4 the suppression of the spectral weight as a function of @xmath1. Please generate the next two sentences of the article

is cut off by @xmath4 and one finds the scaling behavior @xmath5 with a @xmath2-dependent scaling function @xmath6 in which the two energy scales @xmath1 and @xmath4 only enter via their ratio @xcite . these results were exclusively obtained using bosonization within the tomonaga - luttinger ( tl ) model @xcite . using the modern language of renormalization group ( rg ) methods the ( translational invariant )

Suppose that you have an abstract for a scientific paper: the motion of two attractively interacting atoms in an optical lattice is investigated in the presence of a scattering potential . the initial wavefunction can be prepared by using tightly bound exact two - particle eigenfunction for vanishing scattering potential . this allows to numerically simulate the dynamics in the generation of two - particle schrdinger cat states using a scheme recently proposed for scattering of quantum matter wave solitons . . And you have already written the first three sentences of the full article: for ultra - cold atoms in an optical lattice @xcite dynamical aspects include transverse resonances @xcite density waves @xcite , the evolution of quantum fluctuations @xcite , the speed of sound @xcite and time - resolved observation and control of superexchange interactions @xcite . the aim of the present manuscript is to perform exact two - particle dynamics in an optical lattice similar to what has been suggested in ref . @xcite , a bright soliton in a one - dimensional waveguide . as the dispersion relation for. Please generate the next two sentences of the article

the bound two - particle states in the lattice approach case without lattice for suitable parameters , this can be used to quantitatively test the @xmath0-particle predictions of ref . @xcite via exact numerics on the two - particle level for which a soliton is simply a dimer .

Suppose that you have an abstract for a scientific paper: transverse momentum integrated multiplicities in the central region of @xmath0 collisions at lhc energies satisfy koba - nielsen - olesen scaling . we attempt to relate this finding to multiplicity distributions of soft gluons . kno scaling emerges if the effective theory describing color charge fluctuations at a scale on the order of the saturation momentum is approximately gaussian . from an evolution equation for quantum corrections which includes both saturation as well as fluctuations we find that evolution with the qcd @xmath1-function satisfies kno scaling while fixed - coupling evolution does not . thus , non - linear saturation effects and running - coupling evolution are both required in order to reproduce geometric scaling of the dis cross section and kno scaling of virtual dipoles in a hadron wave function . . And you have already written the first three sentences of the full article: the color fields of hadrons boosted to the light cone are thought to grow very strong , parametrically of order @xmath2 where @xmath3 is the coupling @xcite . the fields of nuclei are enhanced further by the high density of valence charges per unit transverse area , which is proportional to the thickness @xmath4 of a nucleus @xcite . in collisions of such strong color fields a large number of soft gluons is released . due to the genuinely non - perturbative dynamics of the strong color fields. Please generate the next two sentences of the article

a semi - hard `` saturation scale '' @xmath5 emerges ; it corresponds to the transverse momentum where the phase space density of produced gluons is of order @xmath6 . the mean multiplicity per unit rapidity in high - energy collisions is then @xmath7 .

Suppose that you have an abstract for a scientific paper: we report on the detection in sloan digital sky survey data of a @xmath0-long tidal stream of stars , extending from ursa major to cancer . the stream has no obvious association with the orbit of any known cluster or galaxy . the contrast of the detected stream is greatest when using a star count filter that is matched to the color - magnitude distribution of stars in m 13 , which suggests that the stars making up the stream are old and metal poor . the visible portion of the stream is very narrow and about 8.5 kpc above the galactic disk , suggesting that the progenitor is or was a globular cluster . while the surface density of the stream varies considerably along its length , its path on the sky is very smooth and uniform , showing no evidence of perturbations by large mass concentrations in the nearby halo . while definitive constraints can not be established without radial velocity information , the stream s projected path and estimates of its distance suggest that we are observing the stream near the perigalacticon of its orbit . . And you have already written the first three sentences of the full article: despite its still limited extent , the sloan digital sky survey ( sdss ) continues to be a remarkable resource for studies of galactic structure . in addition to the large scale features attributed to past galaxy accretion events @xcite , sdss data were used to detect the remarkably strong tidal tails of palomar 5 @xcite . tidal tails of globular clusters are particularly interesting from a galactic structure standpoint as they are expected to be very numerous and to sample the galactic potential much more uniformly than satellite galaxies .. Please generate the next two sentences of the article

moreover , such tidal tails are dynamically very cold @xcite , making them useful for constraining not only the global galactic potential , but also its lumpiness @xcite . substantial tidal streams have now been found associated with at least two of the eight globular clusters in the sdss area ; pal 5 @xcite and ngc 5466 @xcite . in this letter

Suppose that you have an abstract for a scientific paper: we propose algorithms , based on the multi - scale entanglement renormalization ansatz , to obtain the ground state of quantum critical systems in the presence of boundaries , impurities , or interfaces . by exploiting the theory of minimal updates [ ref . : g. evenbly and g. vidal , arxiv:1307.0831 ] , the ground state is completely characterized in terms of a number of variational parameters that is independent of the system size , even though the presence of a boundary , an impurity , or an interface explicitly breaks the translation invariance of the host system . similarly , computational costs do not scale with the system size , allowing the thermodynamic limit to be studied directly and thus avoiding finite size effects e.g. when extracting the universal properties of the critical system . . And you have already written the first three sentences of the full article: entanglement renormalization@xcite is a renormalization group ( rg ) approach to quantum many - body systems on a lattice . as with most rg methods @xcite , it proceeds by coarse - graining the microscopic degrees of freedom of a many - body system , and thus also their hamiltonian @xmath0 , to produce a sequence of effective systems , with hamiltonians @xmath1 that define a flow towards larger length scale / lower energies . entanglement renormalization operates in _ real space _. Please generate the next two sentences of the article

( it does not rely on fourier space analysis ) and it is a _ non - perturbative _ approach ( that is , it can handle interactions of any strength ) . as a result , it has a wide range of applicability , from quantum criticality @xcite to emergent topological order @xcite , from frustrated antiferromagnets @xcite to interacting fermions @xcite and even to interacting anyons @xcite .

Suppose that you have an abstract for a scientific paper: high-@xmath0 galaxy redshift surveys open up exciting possibilities for precision determinations of neutrino masses and inflationary models . the high-@xmath0 surveys are more useful for cosmology than low-@xmath0 ones owing to much weaker non - linearities in matter clustering , redshift - space distortion and galaxy bias , which allows us to use the galaxy power spectrum down to the smaller spatial scales that are inaccessible by low-@xmath0 surveys . we can then utilize the two - dimensional information of the linear power spectrum in angular and redshift space to measure the scale - dependent suppression of matter clustering due to neutrino free - streaming as well as the shape of the primordial power spectrum . to illustrate capabilities of high-@xmath0 surveys for constraining neutrino masses and the primordial power spectrum , we compare three future redshift surveys covering 300 square degrees at @xmath1 , @xmath2 , and @xmath3 . we find that , combined with the cosmic microwave background data expected from the planck satellite , these surveys allow precision determination of the total neutrino mass with the projected errors of @xmath4 , 0.043 , and 0.025 ev , respectively , thus yielding a positive _ detection _ of the neutrino mass rather than an upper limit , as @xmath5 is smaller than the lower limits to the neutrino masses implied from the neutrino oscillation experiments , by up to a factor of 4 for the highest redshift survey . the accuracies of constraining the tilt and running index of the primordial power spectrum , @xmath6 and @xmath7 at @xmath8 , respectively , are smaller than the current uncertainties by more than an order of magnitude , which will allow us to discriminate between candidate inflationary models . in particular , the error on @xmath9 from the future highest redshift survey is not very far away from the prediction of a class of simple inflationary models driven by a massive scalar field with self - coupling , @xmath10 . . And you have already written the first three sentences of the full article: we are living in the golden age of cosmology . various data sets from precision measurements of temperature and polarization anisotropy in the cosmic microwave background ( cmb ) radiation as well as those of matter density fluctuations in the large - scale structure of the universe mapped by galaxy redshift surveys , lyman-@xmath11 forests and weak gravitational lensing observations are in a spectacular agreement with the concordance @xmath12cdm model @xcite . these results assure that theory of cosmological linear perturbations is basically correct , and can accurately describe the evolution of photons , neutrinos , baryons , and collisionless dark matter particles @xcite , for given initial perturbations generated during inflation @xcite . the predictions from linear perturbation theory can be compared with the precision cosmological measurements , in order to derive stringent constraints on the various basic cosmological parameters . future observations with better sensitivity and higher precision will continue to further improve our understanding of the universe .. Please generate the next two sentences of the article

fluctuations in different cosmic fluids ( dark matter , photons , baryons , and neutrinos ) imprint characteristic features in their power spectra , owing to their interaction properties , thermal history , equation of state , and speed of sound . a remarkable example is the acoustic oscillation in the photon - baryon fluid that was generated before the decoupling epoch of photons , @xmath13 , which has been observed in the power spectrum of cmb temperature anisotropy @xcite , temperature polarization cross correlation @xcite , and distribution of galaxies @xcite .

Suppose that you have an abstract for a scientific paper: we study the changes in the fermi surface with electron doping in the lafeaso@xmath0f@xmath1 superconductors with density - functional supercell calculations using the linearized augmented planewave ( lapw ) method . the supercell calculations with explicit f substitution are compared with those obtained from the virtual crystal approximation ( vca ) and from a simple rigid band shift . we find significant differences between the supercell results and those obtained from the rigid - band shift with electron doping , although quite remarkably the supercell results are in good agreement with the virtual crystal approximation ( vca ) where the nuclear charges of the o atoms are slightly increased to mimic the addition of the extra electrons . with electron doping , the two cylindrical hole pockets along @xmath2 shrink in size , and the third hole pocket around @xmath3 disappears for an electron doping concentration in excess of about 7 - 8% , while the two elliptical electron cylinders along @xmath4 expand in size . the spin - orbit coupling does not affect the fermi surface much except to somewhat reduce the size of the third hole pocket in the undoped case . we find that with the addition of the electrons the antiferromagnetic state becomes energetically less stable as compared to the nonmagnetic state , indicating that the electron doping may provide an extra degree of stability to the formation of the superconducting ground state . . And you have already written the first three sentences of the full article: there has been an intense interest to understand the superconductivity of the recently discovered lafeaso.@xcite experiments have found values of the curie temperature ( t@xmath5 ) as large as 26 k for electron doping of lafeaso@xmath0f@xmath1 , 0.04 @xmath6 0.12@xcite . similar values of t@xmath5 are found for hole doping of la with sr but not with ca@xcite . neutron scattering@xcite and optical measurements@xcite find an antiferromagnetic ( afm ) ground state which has been confirmed by previous electronic structure calculations.@xcite the nature of the superconductivity has not been understood , though evidence suggests its unconventional character.@xcite the understanding of the normal - state electronic structure is important and serves as the foundation for understanding the superconductivity .. Please generate the next two sentences of the article

one important question is what happens to the electronic structure when the extra electrons are added to the system via the fluorine dopants . a number of band structure studies have been performed to date to address these questions ; however , most of them use either the simple rigid - band picture of shifting the fermi energy in the band structure of the undoped system or the virtual crystal approximation.@xcite while these methods are expected to describe the rough picture , the actual positions of the dopants could make significant differences to the band structure as compared to the rigid - band shift or to the vca band structure , which is well known from the work on other systems.@xcite in this work , we investigate the band structure using full supercell calculations and study the changes in the fermi surface and the energetics with electron doping , with the fluorine substitution of the oxygen sites .

Suppose that you have an abstract for a scientific paper: an adequate characterization of the dynamics of hamiltonian systems at physically relevant scales has been largely lacking . here we investigate this fundamental problem and we show that the finite - scale hamiltonian dynamics is governed by effective dynamical invariants , which are significantly different from the dynamical invariants that describe the asymptotic hamiltonian dynamics . the effective invariants depend both on the scale of resolution and the region of the phase space under consideration , and they are naturally interpreted within a framework in which the nonhyperbolic dynamics of the hamiltonian system is modeled as a chain of hyperbolic systems . [ phys . rev . e * 71 * , 036215 ( 2005 ) ] . And you have already written the first three sentences of the full article: a comprehensive understanding of hamiltonian dynamics is a long outstanding problem in nonlinear and statistical physics , which has important applications in various other areas of physics . typical hamiltonian systems are nonhyperbolic as they exhibit mixed phase space with coexisting regular and chaotic regions . over the past years , a number of ground - breaking works @xcite have increasingly elucidated the asymptotic behavior of such systems and it is now well understood that , because of the stickiness due to kolmogorov - arnold - moser ( kam ) tori , the chaotic dynamics of typical hamiltonian systems is fundamentally different from that of hyperbolic , fully chaotic systems . here. Please generate the next two sentences of the article

`` asymptotic '' means in the limit of large time scales and small length scales . but in realistic situations , the time and length scales are limited . in the case of hyperbolic systems , this is not a constraint because the ( statistical ) self - similarity of the underlying invariant sets guarantees the fast convergence of the dynamical invariants ( entropies , lyapunov exponents , fractal dimensions , escape rates , etc ) and the asymptotic dynamics turns out to be a very good approximation of the dynamics at finite scales . in nonhyperbolic systems , however , the self - similarity is usually lost because the invariant sets are not statistically invariant under magnifications . as a result ,

Suppose that you have an abstract for a scientific paper: highly variable @xmath0-ray pulses and x - ray flares in grb light curves can result from external shocks rather than central engine activity under the assumption that the grb blast - wave shell does not spread . acceleration of cosmic rays to @xmath1 ev energies can take place in the external shocks of grbs . escape of hadronic energy in the form of uhecrs leads to a rapidly decelerating grb blast wave , which may account for the rapid x - ray declines observed in swift grbs . [ 1999/12/01 v1.4c il nuovo cimento ] . And you have already written the first three sentences of the full article: grb light curves measured with swift consist of a bat light curve in the 15 150 kev range followed , after slewing within @xmath2 s , by a detailed 0.3 10 kev xrt x - ray light curve @xcite . this information supplements our knowledge of the highly variable hard x - ray and @xmath0-ray light curves measured from many grbs with batse and other grb detectors . about one - half of swift grbs show x - ray flares or short timescale structure , sometimes hours or later after the onset of the grb .. Please generate the next two sentences of the article

approximately @xmath3% of the swift grbs display rapid x - ray declines , and an additional @xmath4% display features unlike simple blast wave model predictions @xcite . we make three points in this paper : 1 .

Suppose that you have an abstract for a scientific paper: a bayesian compressive sensing framework is developed for video reconstruction based on the color coded aperture compressive temporal imaging ( cacti ) system . by exploiting the three dimension ( 3d ) tree structure of the wavelet and discrete cosine transformation ( dct ) coefficients , a bayesian compressive sensing inversion algorithm is derived to reconstruct ( up to 22 ) color video frames from a _ single _ monochromatic compressive measurement . both simulated and real datasets are adopted to verify the performance of the proposed algorithm . compressive sensing , video , bayesian , tree structure , wavelet . And you have already written the first three sentences of the full article: the mathematical theory of compressive sensing ( cs ) @xcite asserts that one can acquire signals from measurements whose rate is much lower than the total bandwidth . whereas the cs theory is now well developed , challenges concerning hardware implementations @xcite of cs - based acquisition devices , especially in optics , have only started being addressed . this paper will introduce a color video cs camera capable of capturing low - frame - rate measurements at acquisition , with high - frame - rate video recovered subsequently via computation ( decompression of the measured data ) . the coded aperture compressive temporal imaging ( cacti ) @xcite system uses a moving binary mask pattern to modulate a video sequence within the integration time @xmath0 many times prior to integration by the detector .. Please generate the next two sentences of the article

the number of high - speed frames recovered from a coded - exposure measurement depends on the speed of video modulation . within the cacti framework , modulating the video @xmath1 times per second corresponds to moving the mask @xmath1 pixels within the integration time @xmath0 .

Suppose that you have an abstract for a scientific paper: we introduce the class of intermediate mass binaries named double periodic variables ( dpvs ) , characterized by orbital photometric variability ( ellipsoidal or eclipsing ) in time scales of few days and a long photometric cycle lasting roughly 33 times the orbital period . after a search conducted in the ogle and asas catalogues , we identified 114 of these systems in the magellanic clouds and 11 in the galaxy . we present results of our photometric and spectroscopic campaigns on dpvs conducted during the last years , outlining their main observational characteristics . we present convincing evidence supporting the view that dpvs are semidetached interacting binaries with optically thick discs around the gainer , that experience regular cycles of mass loss into the interstellar medium . the mechanism regulating this long - term process still is unknown but probably is related to relaxation cycles of the circumprimary disc . a key observational fact is the modulation of the @xmath0 of hei 5875 with the long cycle in v393sco . the dpv evolution stage is investigated along with their relationship to algols and w serpentid stars . we conclude that dpvs can be used to test models of non - conservative binary evolution including the formation of circumbinary discs . . And you have already written the first three sentences of the full article: dpvs were discovered in the small magellanic cloud after a search for be stars in the ogle - ii database ( mennickent et al . they were clearly distinguished from other variables by showing 2 linked photometric cycles ( @xmath1 and @xmath2 ) . a spectroscopic monitoring of some of them allowed to associate the short periodicity to the orbital period of a binary ( mennickent et al . 2005 ) whereas the long term variations were found to be reddish and non strictly constant ( mennickent , assman , & sabogal 2006 , michalska et al.2009 ) . the current census of dpvs amounts to 114 in the magellanic clouds and 11 in our galaxy ( see magnitud - color and period - period diagrams in mennickent & koaczkowski 2009a ) .. Please generate the next two sentences of the article

after the discovery of additional variability in v393sco ( pilecki & szczygiel 2007 ) , we recognized it as the first dpv in our galaxy . later we found that in the past an additional long cycle was also reported for the galactic dpv aumon ( lorenzi 1985 ) .

Suppose that you have an abstract for a scientific paper: we discuss the possibilities of the basel models in its lowest temperature boundary ( t@xmath0@xmath12500 k for cool giants ) to provide the t@xmath0 of agb stars . we present the first step of our work , by comparing our predictions for the agb star r fornacis with the results of lorenz - martins & lefvre ( 1994 ) based on the dust spectral energy distribution . . And you have already written the first three sentences of the full article: main sequence stars with mass in the range 0.9 - 9 m@xmath2 evolve through a double shell burning phase , refered to as the asymptotic giant branch ( agb ) phase of evolution . this phase is characterized by carbon dredge up of the core to the surface after each thermal pulse - helium shell flash - ( iben & renzini 1983 ) . the temperatures of these objects are very badly known .. Please generate the next two sentences of the article

although they are highly variable , their determination from static models such as assumed in the basel library can be justified as a first approximation . in order to explore the capabilities of the basel library ( lejeune , cuisinier & buser 1997 , 1998 and references therein , see also lastennet , lejeune & cuisinier , these proceedings ) to predict correct temperatures for such cool agb stars , we compare our results from synthetic infrared photometry of the stellar photosphere with the detailed study of lorenz - martins & lefvre ( 1994 ) of the agb carbon star r fornacis . their work is based on a modelling of the spectral energy distribution of the dust envelope , where they put tight constraints on the temperature of the heating source .

Suppose that you have an abstract for a scientific paper: we study nonlinear random resistor diode networks at the transition from the non percolating to the directed percolating phase . the resistor - like bonds and the diode - like bonds under forward bias voltage obey a generalized ohm s law , @xmath0 . based on general grounds as symmetries and relevance we develop a field theoretic model . we focus on the average two - port resistance , which is governed at the transition by the resistance exponent @xmath1 . by employing renormalization group methods we calculate @xmath1 for arbitrary @xmath2 to one - loop order . then we address the fractal dimensions characterizing directed percolation clusters . via considering distinct values of the nonlinearity @xmath2 , we determine the dimension of the red bonds , the chemical path and the backbone to two - loop order . # 1@xmath3#1 . And you have already written the first three sentences of the full article: percolation@xcite describes the passage of an influence through a medium which is irregularly structured in the sense that the influence can propagate through some regions whereas it can not pass other areas . prominent examples for such media are computer networks like the internet where information propagates and irregularity can be caused by random switch failures or other technical problems . a particularly simple percolation model is the random resistor network ( rrn ) . in this model. Please generate the next two sentences of the article

the irregular medium is given by a , say hypercubic , lattice in which bonds between nearest neighboring sites are randomly occupied with a probability @xmath4 . the influence corresponds to an external current @xmath5 , which is injected at a terminal site @xmath6 and withdrawn at another terminal site @xmath7 .

Suppose that you have an abstract for a scientific paper: we investigate the environments of quasars such as number distribution of galaxies using a semi - analytic model which includes both galaxy and quasar formations based on the hierarchical clustering scenario . we assume that a supermassive black hole is fueled by accretion of cold gas and that it is a source of quasar activity during a major merger of the quasar host galaxy with another galaxy . this major merger causes spheroid formation of the host galaxy . our model can reproduce not only general form of the galaxy luminosity functions in the local universe but also the observed relation between a supermassive black hole mass and a spheroid luminosity , the present black hole mass function and the quasar luminosity functions at different redshifts . using this model , we predict the mean number of quasars per halo , bias parameter of quasars and the probability distribution of the number of galaxies around quasars . in our model , analysis of the mean number of quasars per halo shows that the spatial distribution of galaxies is different from that of quasars . furthermore , we found from calculation of the probability distribution of galaxy numbers that at @xmath0 , most quasars are likely to reside in galaxy groups . on the other hand , at @xmath1 most quasars seem to reside in more varied environments than at a lower redshift ; quasars reside in environments ranging from small groups of galaxies to clusters of galaxies . comparing these predictions with observations in future will enable us to constrain our quasar formation model . . And you have already written the first three sentences of the full article: the environments of quasars provide important clues to the physical processes of their formation and also yield important information about the relations between the distribution of quasars and the large - scale structure of the universe . for more than three decades , we have known that quasars are associated with enhancements in the spatial distributions of galaxies ( @xcite ) . studies of the environments of quasars in the nearby universe ( @xmath2 ) have shown that quasars reside in environments ranging from small to moderate groups of galaxies rather than in rich clusters ( e.g. @xcite ; @xcite ; @xcite ) . in order to interpret the observational results of the environments of quasars at low redshifts and predict the environments of quasars at high redshifts , a physical model of quasar formation based on cosmological context. Please generate the next two sentences of the article

is required . it has become widely accepted that quasars are fueled by accretion of gas onto supermassive black holes ( smbhs ) in the nuclei of host galaxies since @xcite proposed this idea on quasars .

Suppose that you have an abstract for a scientific paper: the entropy of an ergodic source is the limit of properly rescaled 1-block entropies of sources obtained applying successive non - sequential recursive pairs substitutions @xcite,@xcite . in this paper we prove that the cross entropy and the kullback - leibler divergence can be obtained in a similar way . _ keywords _ : information theory , source and channel coding , relative entropy . . And you have already written the first three sentences of the full article: kullback - leibler ( kl ) divergence ( relative entropy ) can be considered as a measure of the difference / dissimilarity between sources . estimating kl divergence from finite realizations of a stochastic process with unknown memory is a long - standing problem , with interesting mathematical aspects and useful applications to automatic categorization of symbolic sequences . namely , an empirical estimation of the divergence can be used to classify sequences ( for approaches to this problem using other methods , in particular true metric distances , see @xcite , @xcite ; see also @xcite ) . in @xcite ziv and. Please generate the next two sentences of the article

merhav showed how to estimate the kl divergence between two sources , using the parsing scheme of lz77 algorithm @xcite on two finite length realizations . they proved the consistence of the method by showing that the estimate of the divergence for two markovian sources converges to their relative entropy when the length of the sequences diverges .

Suppose that you have an abstract for a scientific paper: we explore the spectral properties of the time - dependent maxwell s equations for a plane interface between a metamaterial represented by the drude model and the vacuum , which fill respectively complementary half - spaces . we construct explicitly a generalized fourier transform which diagonalizes the hamiltonian that describes the propagation of transverse electric waves . this transform appears as an operator of decomposition on a family of generalized eigenfunctions of the problem . it will be used in a forthcoming paper to prove both limiting absorption and limiting amplitude principles . * keywords : * negative index materials ( nims ) , drude model , maxwell equations , generalized eigenfunctions . . And you have already written the first three sentences of the full article: in the last years , metamaterials have generated a huge interest among communities of physicists and mathematicians , owing to their extraordinary properties such as negative refraction @xcite , allowing the design of spectacular devices like the perfect flat lens @xcite or the cylindrical cloak in @xcite . such properties result from the possibility of creating artificially microscopic structures whose macroscopic electromagnetic behavior amounts to negative electric permittivity @xmath0 and/or negative magnetic permeability @xmath1 within some frequency range . such a phenomenon can also be observed in metals in the optical frequency range @xcite : in this case one says that this material is _ a negative material _ @xcite .. Please generate the next two sentences of the article

thanks to these negative electromagnetic coefficients , waves can propagate at the interface between such a negative material and a usual dielectric material @xcite . these waves , often called _ surface plasmon polaritons _ , are localized near the interface and allow then to propagate signals in the same way as in an optical fiber , which may lead to numerous physical applications .

Suppose that you have an abstract for a scientific paper: when integrals in the standard tremaine - weinberg method are evaluated for the case of a realistic model of a doubly barred galaxy , their modifications introduced by the second rotating pattern are in accord with what can be derived from a simple extension of that method , based on separation of tracer s density . this extension yields a qualitative argument that discriminates between prograde and retrograde inner bars . however , the estimate of the value of inner bar s pattern speed requires further assumptions . when this extension of the tremaine - weinberg method is applied to the recent observation of the doubly barred galaxy ngc 2950 , it indicates that the inner bar there is counter - rotating , possibly with the pattern speed of @xmath0 km s@xmath1 arcsec@xmath1 . the occurrence of counter - rotating inner bars can constrain theories of galaxy formation . galaxies : individual ( ngc 2950 ) galaxies : kinematics and dynamics galaxies : structure . And you have already written the first three sentences of the full article: bars within bars appear to be a common phenomenon in galaxies . recent surveys indicate that up to 30% of early - type barred galaxies contain such double bars ( erwin & sparke 2002 ; laine et al . inner bars remain distinct in near infrared ( wozniak et al .. Please generate the next two sentences of the article

1995 ) , therefore fairly old stars must contribute to their light . the relative orientation of the two bars in doubly barred galaxies is random , therefore it is likely that the bars rotate with different pattern speeds .

Suppose that you have an abstract for a scientific paper: under the assumptions that molecular clouds are nearly spatially and temporally isothermal and that the density peaks ( `` cores '' ) within them are formed by turbulent fluctuations , we argue that cores can not reach a hydrostatic ( or magneto - static ) state as a consequence of their formation process . in the non - magnetic case , this is a consequence of the fact that , for cores at the same temperature of the clouds , the necessary bonnor - ebert truncation at a finite radius is not feasible , unless it amounts to a shock , which is clearly a dynamical feature , or the core is really embedded in hotter gas . otherwise , quiescent cores must have non - discontinuous density profiles until they merge with their parent cloud , constituting extended structures . for these , we argue that any equilibrium configuration with non - vanishing central density is unstable . since the cores environment ( the molecular cloud ) is turbulent , no reason exists for them to settle into an unstable equilibrium . instead , in this case , cores must be dynamical entities that can either be pushed into collapse , or else `` rebound '' towards the mean pressure and density as the parent cloud . nevertheless , rebounding cores are delayed in their re - expansion by their own self - gravity . we give a crude estimate for the re - expansion time as a function of the closeness of the final compression state to the threshold of instability , finding typical values @xmath0 myr , i.e. , of the order of a few free - fall times . our results support the notion that not all cores observed in molecular clouds need to be on route to forming stars , but that instead a class of `` failed cores '' should exist , which must eventually re - expand and disperse , and which can be identified with observed starless cores . in the magnetic case , recent observational and theoretical work suggests that all cores are critical or supercritical , and are thus qualitatively equivalent to the non - magnetic case . this is , however.... And you have already written the first three sentences of the full article: one of the most important goals in the study of star formation is to understand the state and physical conditions of the molecular cloud cores from which the stars form . the prevailing view concerning low - mass - star - forming cores is that they are quasi - static equilibrium configurations supported against gravitational collapse by a combination of magnetic , thermal and turbulent pressures ( e.g. , mouschovias 1976a , b ; shu , adams & lizano 1987 ) . when considering only thermal pressure , two variants of the equilibrium structures are usually discussed : either singular isothermal structures , with diverging central densities and smooth @xmath1 density dependence extending to infinity ( e.g. , shu et al .. Please generate the next two sentences of the article

1987 ) , or finite - central density structures , truncated at some finite radius and confined by the pressure of some external medium , generally assumed to be at higher temperatures and lower densities than the isothermal core ( ebert 1955 ; bonnor 1956 ) . more recently , the equilibria of non - axisymmetric configurations have also been studied ( e.g. , fiege & pudritz 2000 ; curry 2000 ; galli et al .

Suppose that you have an abstract for a scientific paper: the numerical convergence of smoothed particle hydrodynamics ( sph ) can be severely restricted by random force errors induced by particle disorder , especially in shear flows , which are ubiquitous in astrophysics . the increase in the number @xmath0 of neighbours when switching to more extended smoothing kernels _ at fixed resolution _ ( using an appropriate definition for the sph resolution scale ) is insufficient to combat these errors . consequently , trading resolution for better convergence is necessary , but for traditional smoothing kernels this option is limited by the pairing ( or clumping ) instability . therefore , we investigate the suitability of the wendland functions as smoothing kernels and compare them with the traditional b - splines . linear stability analysis in three dimensions and test simulations demonstrate that the wendland kernels avoid the pairing instability for _ all _ @xmath0 , despite having vanishing derivative at the origin ( disproving traditional ideas about the origin of this instability ; instead , we uncover a relation with the kernel fourier transform and give an explanation in terms of the sph density estimator ) . the wendland kernels are computationally more convenient than the higher - order b - splines , allowing large @xmath0 and hence better numerical convergence ( note that computational costs rise sub - linear with @xmath0 ) . our analysis also shows that at low @xmath0 the quartic spline kernel with @xmath1 obtains much better convergence then the standard cubic spline . [ firstpage ] hydrodynamics methods : numerical methods : @xmath2-body simulations . And you have already written the first three sentences of the full article: smoothed particle hydrodynamics ( sph ) is a particle - based numerical method , pioneered by @xcite and @xcite , for solving the equations of hydrodynamics ( recent reviews include @xcite ; @xcite ; @xcite ; @xcite ) . in sph , the particles trace the flow and serve as interpolation points for their neighbours . this lagrangian nature of sph makes the method particularly useful for astrophysics , where typically open boundaries apply , though it becomes increasingly popular also in engineering ( e.g. * ? ? ?. Please generate the next two sentences of the article

the core of sph is the density estimator : the fluid density is _ estimated _ from the masses @xmath3 and positions @xmath4 of the particles via ( the symbol @xmath5 denotes an sph _ estimate _ ) @xmath6 where @xmath7 is the _ smoothing kernel _ and @xmath8 the _ smoothing scale _ , which is adapted for each particle such that @xmath9constant ( with @xmath10 the number of spatial dimensions ) . similar estimates for the value of any field can be obtained , enabling discretisation of the fluid equations . instead , in _ conservative _ sph , the equations of motion for the particles are derived , following @xcite , via a variational principle from the discretised lagrangian @xmath11\ ] ] @xcite . here

Suppose that you have an abstract for a scientific paper: we report a detailed examination of the fine structure inside flare ribbons and the temporal evolution of this fine structure during the x2.5 solar flare that occurred on 2004 november 10 . we examine elementary bursts of the @xmath0 ( @xmath11550 ) emission lines seen as local transient brightenings inside the flare ribbons in the ultraviolet ( 1600 ) images taken with transition region and coronal explorer , and we call them @xmath0 kernels . this flare was also observed in h@xmath2 with the sartorius 18 cm refractor telescope at kwasan observatory , kyoto university , in hard x - rays ( hxr ) with reuven ramaty high energy solar spectroscopic imager . many @xmath0 kernels , whose sizes were comparable to or less than 2 , were found to brighten successively during the evolution of the flare ribbon . the majority of them were well correlated with the h@xmath2 kernels in both space and time , while some of them were associated with the hxr emission . these kernels were thought to be caused by the precipitation of nonthermal particles at the foot points of the reconnecting flare loops . the time profiles of the @xmath0 kernels showed intermittent bursts , whose peak intensity , duration and time interval were well described by power - law distribution functions . this result is interpreted as an avalanching system of `` self - organized criticality '' of a single event or by fractal current sheets in the impulsive reconnection region . . And you have already written the first three sentences of the full article: hard x - ray ( hxr ) and microwave emissions show fine structures both temporally and spatially during a solar flare , which revealed that a highly - fragmented and intermittent particle acceleration occurs ( e.g. * ? ? ? * ; * ? ? ? this fragmented structure of solar flares indicates that a flare is an ensemble of a vast amount of small scale energy release .. Please generate the next two sentences of the article

statistical studies of solar flares have also shown that various kinds of physical parameters of flares , like peak intensity , flare duration , waiting time of soft x - ray ( sxr ) emissions between discrete events , are well described with power - law distributions ( e.g. * ? ? ? * ; * ? ? ?

Suppose that you have an abstract for a scientific paper: we study the quantum phase transition between abelian and non - abelian phases in an extended kitaev spin model on the honeycomb lattice , where the periodic boundary condition is applied by placing the lattice on a torus . our analytical results show that this spin model exhibits a continuous quantum phase transition . also , we reveal the relationship between bipartite entanglement and the ground - state energy . our approach directly shows that both the entanglement and the ground - state energy can be used to characterize the topological quantum phase transition in the extended kitaev spin model . . And you have already written the first three sentences of the full article: quantum phase transitions , which occur when a driving parameter in the hamiltonian of the system changes across a critical point , play a central role in condensed matter physics @xcite . while most quantum phase transitions can be characterized by symmetry breaking , there is also an exception that can only be witnessed by topological order ( see , e.g. , @xcite ) . signatures of topological order in many - body quantum systems can characterize a topological quantum phase transition and include , e.g. , the existence of excitations obeying fractional statistics ( see , e.g. , @xcite ) , ground - state degeneracy related to the topology of the system ( instead of the symmetry ) ( see , e.g. , @xcite ) , and topological entanglement entropy @xcite . in particular , the spectral chern number @xcite serves as a topological number for characterizing a two - dimensional ( 2d ) system of noninteracting ( or weakly interacting ) fermions with an energy gap . without closing the gap , energy spectra with different chern numbers can not be deformed into each other @xcite . this is because a topological quantum phase transition occurs when changing the chern number .. Please generate the next two sentences of the article

recently , it was shown @xcite that the topological quantum phase transition in the kitaev spin model can be characterized by nonlocal - string order parameters . in an appropriate dual representation , this order parameter can become local and the basic concept of landau theory of continuous phase transition is also applicable @xcite . in the kitaev model , a @xmath0-spin

Suppose that you have an abstract for a scientific paper: dilute fermi systems with large @xmath0-wave scattering length @xmath1 exhibit universal properties if the interparticle spacing @xmath2 greatly exceeds the range of the underlying two - body interaction potential . in this regime , @xmath2 is the only relevant length scale and observables such as the energy per particle depend only on @xmath2 ( or , equivalently , the energy @xmath3 of the free fermi gas ) . this paper investigates bose and fermi systems with non - vanishing angular momentum @xmath4 using the lowest order constrained variational method . we focus on the regime where the generalized scattering length becomes large and determine the relevant length scales . for bose gases with large generalized scattering lengths , we obtain simple expressions for the energy per particle in terms of a @xmath4-dependent length scale @xmath5 , which depends on the range of the underlying two - body potential and the average interparticle spacing . we discuss possible implications for dilute two - component fermi systems with finite @xmath4 . furthermore , we determine the equation of state of liquid and gaseous bosonic helium . . And you have already written the first three sentences of the full article: the experimental realization of dilute degenerate bose and fermi gases has led to an explosion of activities in the field of cold atom gases . a particularly intriguing feature of atomic bose and fermi gases is that their interaction strengths can be tuned experimentally through the application of an external magnetic field in the vicinity of a feshbach resonance @xcite . this external knob allows dilute systems with essentially any interaction strength , including infinitely strongly attractive and repulsive interactions , to be realized . feshbach resonances have been experimentally observed for @xmath0- , @xmath6- and @xmath7-wave interacting gases @xcite and have been predicted to exist also for higher partial waves .. Please generate the next two sentences of the article

a feshbach resonance arises due to the coupling of two born - oppenheimer potential curves coupled through a hyperfine hamiltonian , and requires , in general , a multi - channel description . for @xmath0-wave interacting systems , feshbach resonances can be classified as broad or narrow @xcite . whether a resonance is broad or narrow depends on whether the energy width of the resonance is large or small compared to the characteristic energy scale , such as the fermi energy or the harmonic oscillator energy , of the system .

Suppose that you have an abstract for a scientific paper: scattering of two baryons in the large-@xmath0 gross - neveu model via the time - dependent dirac - hartree - fock approach has recently been solved in closed analytical form . here , we generalize this result to scattering processes involving any number and complexity of the scatterers . the result is extrapolated from the solution of few baryon problems , found via a joint ansatz for the scalar mean field and the dirac spinors , and presented in analytical form . it has been verified numerically for up to 8-baryon problems so far , but a full mathematical proof is still missing . examples shown include the analogue of proton - nucleus and nucleus - nucleus scattering in this toy model . all the parameters of the general result can be fixed by one- and two - baryon input only . we take this finding as evidence for factorized scattering , but on the level of composite multi - fermion states rather than elementary fermions . . And you have already written the first three sentences of the full article: the massless gross - neveu ( gn ) model @xcite is the 1 + 1 dimensional quantum field theory of @xmath0 flavors of massless dirac fermions , interacting through a scalar - scalar contact interaction . suppressing flavor labels as usual , its lagrangian reads @xmath1 the physics phenomena inherent in this simple looking lagrangian are particularly rich and accessible in the t hooft limit ( @xmath2 const . ) , to which we restrict ourselves from here on . the gn model can be thought of as relativistic version of particles moving along a line and interacting via an attractive @xmath3-potential .. Please generate the next two sentences of the article

however , it exhibits many non - trivial features characteristic for relativistic quantum fields such as covariance , renormalizability , asymptotic freedom , dimensional transmutation , spontaneous symmetry breaking , interacting dirac sea . it is also one of the few models known where most of the non - perturbative questions of interest to strong interaction physics can be answered in closed analytical form .

Suppose that you have an abstract for a scientific paper: wikipedia is a free internet encyclopedia with an enormous amount of content . this encyclopedia is written by volunteers with various backgrounds in a collective fashion ; anyone can access and edit most of the articles . this open - editing nature may give us prejudice that wikipedia is an unstable and unreliable source ; yet many studies suggest that wikipedia is even more accurate and self - consistent than traditional encyclopedias . scholars have attempted to understand such extraordinary credibility , but usually used the number of edits as the unit of time , without consideration of real - time . in this work , we probe the formation of such collective intelligence through a systematic analysis using the entire history of @xmath0 english wikipedia articles , between 2001 and 2014 . from this massive data set , we observe the universality of both timewise and lengthwise editing scales , which suggests that it is essential to consider the real - time dynamics . by considering real time , we find the existence of distinct growth patterns that are unobserved by utilizing the number of edits as the unit of time . to account for these results , we present a mechanistic model that adopts the article editing dynamics based on both editor - editor and editor - article interactions . the model successfully generates the key properties of real wikipedia articles such as distinct types of articles for the editing patterns characterized by the interrelationship between the numbers of edits and editors , and the article size . in addition , the model indicates that infrequently referred articles tend to grow faster than frequently referred ones , and articles attracting a high motivation to edit counterintuitively reduce the number of participants . we suggest that this decay of participants eventually brings inequality among the editors , which will become more severe with time . . And you have already written the first three sentences of the full article: humankind has accrued _ a priori _ knowledge since the onset of _ homo sapiens_. from ancient cave paintings to modern research papers , the species desire toward sedimentation has been displayed as a documentary . an encyclopedia , a set of documents that contains a vast collection of information from the entire field of human knowledge , has played a pivotal role in disseminating these legacies @xcite . conventionally , a group of experts devote their expertise to these encyclopedias @xcite . taking advantage of technological developments , media that publish encyclopedias keep abreast of the times : handwriting , letterpress printing , and optical disks .. Please generate the next two sentences of the article

the emergence of information technology has opened a new era of publishing traditional encyclopedias on the world wide web @xcite , which offers a variety of references and up - to - date information . although these new media can reduce the publication price , encyclopedia editing is still costly .

Suppose that you have an abstract for a scientific paper: the sign change of the slope of the directed flow of baryons has been predicted as a signal for a first order phase transition within fluid dynamical calculations . recently , the directed flow of identified particles has been measured by the star collaboration in the beam energy scan ( bes ) program . in this article , we examine the collision energy dependence of directed flow @xmath0 in fluid dynamical model descriptions of heavy ion collisions for @xmath1 gev . the first step is to reproduce the existing predictions within pure fluid dynamical calculations . as a second step we investigate the influence of the order of the phase transition on the anisotropic flow within a state - of - the - art hybrid approach that describes other global observables reasonably well . we find that , in the hybrid approach , there seems to be no sensitivity of the directed flow on the equation of state and in particular on the existence of a first order phase transition . in addition , we explore more subtle sensitivities like e.g. the cooper - frye transition criterion and discuss how momentum conservation and the definition of the event plane affects the results . at this point , none of our calculations matches qualitatively the behavior of the star data , the values of the slopes are always larger than in the data . . And you have already written the first three sentences of the full article: the anisotropic flow of particles has been an interesting observable , since data from the first heavy ion collisions became available at the bevalac . the deflection of the produced particles in the reaction plane ( defined as the plane between impact parameter and beam direction ) can be quantified by the so called directed flow , @xmath0 . at very low beam energies of @xmath2 gev per nucleon , the rotation of the system will lead to a strong overall directed flow coefficient , that has been observed and understood within fluid dynamical calculations @xcite . at very high beam energies ,. Please generate the next two sentences of the article

as they are achieved at the large hadron collider ( lhc ) and the relativistic heavy ion collider ( rhic ) , the slope of the traditional directed flow is close to zero at midrapidity due to the almost perfect transparency of the colliding nuclei . the small negative slope of charged particles ( mostly pions ) at top rhic energy can be explained within a fluid dynamical model and a slightly tilted initial state @xcite as well as a hadronic transport model @xcite . in the last 3 years more studies where focused on odd flow coefficients related to initial state fluctuations .

Suppose that you have an abstract for a scientific paper: we present a phenomenological theory of the interplay between nematic order and superconductivity in the vicinity of a vortex induced by an applied magnetic field . nematic order can be strongly enhanced in the vortex core . as a result , the vortex cores become elliptical in shape . for the case where there is weak bulk nematic order at zero magnetic field , the field - induced eccentricity of the vortex core has a slow power - law decay away from the core . conversely , if the nematic order is field - induced , then the eccentricity is confined to the vortex core . we discuss the relevance of our results to recent scanning tunneling microscopy experiments on fese ( song _ et al . _ , science * 332 * , 1410 ( 2011 ) ) . . And you have already written the first three sentences of the full article: the unconventional superconductors have a rich phase diagram determined by the interplay of multiple competing , or coexisting , types of order . nematic order ( which breaks the c@xmath0 symmetry of the underlying square lattice down to c@xmath1 ) has been shown to emerge in certain regimes of the phase diagrams of the copper - oxide @xcite and the iron - based @xcite superconductors . in the latter case , the nematic order accompanies ( and in some cases , precedes ) the magnetic order which occurs at a wavevector that breaks the lattice rotational symmetry .. Please generate the next two sentences of the article

recently , the structure of the vortex cores in the mixed state of clean fese films was studied by means of scanning tunneling microscopy ( stm ) @xcite . strong anisotropy was observed in the zero bias conductance map around the cores , which have an eccentricity of the order of unity .

Suppose that you have an abstract for a scientific paper: accelerator neutrino oscillation experiments seek to make precision measurements of the neutrino flavor oscillations @xmath0 in order to determine the mass hierarchy of neutrinos and to search for cp violation in neutrino oscillations . these experiments are currently performed with beams of muon neutrinos at energies near 1 gev where the charged - current quasi - elastic interactions @xmath1 and @xmath2 dominate the signal reactions . we examine the difference between the quasi - elastic cross - sections for muon and electron neutrinos and anti - neutrinos and estimate the uncertainties on these differences . . And you have already written the first three sentences of the full article: since the invention of neutrino beams at accelerators and the consequent discovery of the two flavors of neutrinos@xcite , the reactions @xmath3 and @xmath4 , which are the dominant reactions of muon and electron neutrinos with energies from @xmath5 mev to @xmath6 gev , have played an important role in studies of neutrino flavor . these charged - current quasi - elastic ( ccqe ) interactions are important not only because they identify the flavor of the neutrino through the production of the lepton in the final state , but also because the two body kinematics permit a measurement of the neutrino energy from only the observation of the final state lepton . accelerator neutrino experiments like t2k@xcite , nova@xcite and a number of proposed experiments seek to make precision measurements of the neutrino flavor oscillations @xmath0 or @xmath7 in order to determine the mass hierarchy of neutrinos and to search for cp violation in neutrino oscillations .. Please generate the next two sentences of the article

uncertainties on differences between these cross - sections for muon and electron neutrinos will contribute to experimental uncertainties in these flavor oscillation measurements . interactions of the charged - current with fundamental fermions , such as @xmath8 , have no uncertainties in the differences between the reactions for muon and electron neutrino interactions because the weak interaction is experimentally observed to be flavor universal . in particular , the effect of the final state lepton mass in this two body reaction of fundamental fermions can be unambiguously calculated .

Suppose that you have an abstract for a scientific paper: graphical model learning and inference are often performed using bayesian techniques . in particular , learning is usually performed in two separate steps . first , the graph structure is learned from the data ; then the parameters of the model are estimated conditional on that graph structure . while the probability distributions involved in this second step have been studied in depth , the ones used in the first step have not been explored in as much detail . in this paper , we will study the prior and posterior distributions defined over the space of the graph structures for the purpose of learning the structure of a graphical model . in particular , we will provide a characterisation of the behaviour of those distributions as a function of the possible edges of the graph . we will then use the properties resulting from this characterisation to define measures of structural variability for both bayesian and markov networks , and we will point out some of their possible applications . marco scutari + genetics institute , university college london , united kingdom + m.scutari@ucl.ac.uk graphical models @xcite stand out among other classes of statistical models because of their use of graph structures in modelling and performing inference on multivariate , high - dimensional data . the close relationship between their probabilistic properties and the topology of the underlying graphs represents one of their key features , as it allows an intuitive understanding of otherwise complex models . in a bayesian setting , this duality leads naturally to split model estimation ( which is usually called _ learning _ ) in two separate steps @xcite . in the first step , called _ structure learning _ , the graph structure @xmath0 of the model is estimated from the data . the presence ( absence ) of a particular edge between two nodes in @xmath0 implies the conditional ( in)dependence of the variables corresponding to such nodes . in the second step , called _ parameter learning _ , the.... And you have already written the first three sentences of the full article: graphical models @xcite are a class of statistical models which combine the rigour of a probabilistic approach with the intuitive representation of relationships given by graphs . they are composed by a set @xmath15 of _ random variables _ describing the data @xmath4 and a _ graph _ @xmath16 in which each _ vertex _ or _ node _ @xmath17 is associated with one of the random variables in @xmath18 .. Please generate the next two sentences of the article

nodes and the corresponding variables are usually referred to interchangeably . the _ edges _

Suppose that you have an abstract for a scientific paper: within the borel qcd sum rule approach at finite baryon density we study the role of the four - quark condensates for the modifications of the vector mesons @xmath0 , @xmath1 and @xmath2 in nuclear matter . we find that in - medium modifications of the @xmath0 and @xmath1 mesons are essentially dominated by the dependence of the 4-quark condensate on the nucleon density . in particular , the numerical value of a parameter ( @xmath3 ) , which describes the strength of the density dependence of the 4-quark condensate beyond the mean - field approximation , governs the decrease of the @xmath0 mass as a function of the density . for the @xmath1 meson the sign of the in - medium mass shift is changed by variations of @xmath3 . to study consistently the in - medium broadening of the light vector mesons we employ @xmath4 and @xmath5 scattering amplitudes derived recently from a covariant unitary coupled channel approach adjusted to pion- and photo - induced reactions . in contrast to the @xmath0 and @xmath1 mesons , the in - medium mass of the @xmath2 meson is directly related to the chiral ( strange ) quark condensate . measurements of the vector meson spectral change in heavy - ion collisions with hades can shed light on the yet unknown density dependence of the 4-quark condensate . . And you have already written the first three sentences of the full article: changes of the vector meson properties in strongly interacting matter at finite baryon density and temperature are presently of great interest , both theoretically and experimentally . in particular , the current heavy - ion experiments with the detector hades @xcite at the heavy - ion synchrotron sis18 ( gsi , darmstadt ) are mainly aimed at measuring in - medium modifications of light vector meson via the @xmath6 decay channel with high accuracy . one of the primary goals of the future experiments planned at sis100/200 is also to study very dense baryon matter and the expected strong changes of the in - medium hadrons . it is widely believed that the in - medium spectral change of the light mesons is related to the chiral symmetry restoration at finite temperature and baryon density .. Please generate the next two sentences of the article

there are indeed various theoretical indications concerning an important sensitivity of the meson spectral density on the partial restoration of the chiral symmetry in a hot / dense nuclear medium . for instance , at finite temperature the vector and axial - vector meson correlators become mixed in accordance with in - medium weinberg sum rules @xcite .

Suppose that you have an abstract for a scientific paper: we use galaxies detected in a deep ultraviolet xmm - newton optical monitor image and a model that predicts uv galaxy counts based on local counts and evolution parameters to constrain galaxy evolution to z=1.2 . the 17 square 2000 ( uvw2 filter ) image was taken as part of the xmm - om team s guaranteed time program . we detect sources in this image to a flux limit of 2.7 @xmath0 10@xmath1 ergs @xmath2 s@xmath3 @xmath3 ( ab magnitude = 22 ) . since some of the sources may be stars , we perform a number of checks , including shape , color and implied distance to remove stars from the detected counts . we find galaxy number counts as a function of magnitude roughly in agreement @xcite , but again find these counts are in excess of evolution models . the excess counts at faint magnitudes may provide evidence for either a new population of galaxies emerging around z=0.7 or more dramatic evolution than some earlier predictions . the integrated light from the detected galaxies totals 3236 ph @xmath2 s@xmath3 @xmath3 sr@xmath3 , placing a firm lower limit on the integrated uv light from galaxies . . And you have already written the first three sentences of the full article: measurements of the integrated light from a galaxy at 2000 provides a fairly direct measure of the instantaneous rate of star formation , since the massive stars that provide most of this radiation are short - lived compared with the age of the galaxy . knowledge of the star formation rate also gives a measure of the rate of heavy element production in a galaxy , or in the universe when a large sample of galaxies are measured ( @xcite ) . the integrated light from these galaxies contributes to the extragalactic background light at ultraviolet wavelengths , whose main sources are hot stars and active galactic nuclei .. Please generate the next two sentences of the article

measurements of galaxy number counts in the ultraviolet have been made by @xcite using the foca balloon - borne uv telescope , @xcite and @xcite using hst archival fields . these data have been interpreted with models that predict number counts based on galaxy spectral energy distributions ( sed s ) and luminosity functions , such as those of @xcite and @xcite .

Suppose that you have an abstract for a scientific paper: we study the possible existence of deconfined quark matter in the interior of neutron stars using the nambu jona - lasinio model to describe the quark phase . we find that typical neutron stars with masses around 1.4 solar masses do not possess any deconfined quark matter in their center . this can be traced back to the property of the njl model which suggests a large constituent strange quark mass over a wide range of densities . . And you have already written the first three sentences of the full article: at large temperatures or large densities hadronic matter is expected to undergo two phase transitions : one which deconfines quarks ( and gluons ) and one which restores chiral symmetry . up to now it is an unsettled issue whether these two phase transitions are distinct or coincide . the more , it is even unclear whether there are real phase transitions or only rapid crossover transitions .. Please generate the next two sentences of the article

such transitions have received much attention in heavy ion physics as well as in the context of neutron stars which provide a unique environment to study cold matter at supernuclear densities @xcite . even though a deconfinement phase transition seems intuitively evident at large enough densities , from a theoretical point of view a confirmation of the existence of a deconfined quark phase in neutron stars is so far limited by the uncertainties in modeling qcd at large densities . all the more it is important to study and compare different available models to shed some light on similarities and differences with respect to the behavior of matter at large densities as well as on the corresponding predictions of neutron star properties like e.g. its mass and radius . in the future such experience may prove to be useful if either an improved understanding of matter under extreme conditions provides a more exclusive selection between the various models or new experimental results on neutron star properties are available to set more stringent constraints . usually the quark matter phase is modeled in the context of the mit bag model @xcite as a fermi gas of @xmath0 , @xmath1 , and @xmath2 quarks . in this model the phenomenological bag constant @xmath3 is introduced to mimic qcd interactions to a certain degree .

Suppose that you have an abstract for a scientific paper: the main purpose of this article is to extend some of the ideas from schubert calculus to the more general setting of hamiltonian torus actions on compact symplectic manifolds with isolated fixed points . given a generic component @xmath0 of the moment map , which is a morse function , we define a canonical class @xmath1 in the equivariant cohomology of the manifold @xmath2 for each fixed point @xmath3 . when they exist , canonical classes form a natural basis of the equivariant cohomology of @xmath2 ; in particular , when @xmath2 is a flag variety , these classes are the equivariant schubert classes . we show that the restriction of a canonical class @xmath1 to a fixed point @xmath4 can be calculated by a rational function which depends only on the value of the moment map , and the restriction of other canonical classes to points of index exactly two higher . therefore , the structure constants can be calculated by a similar rational function . our restriction formula is _ manifestly positive _ in many cases , including when @xmath2 is a flag manifold . finally , we prove the existence of integral canonical classes in the case that @xmath2 is a gkm manifold and @xmath0 is _ index increasing_. in this case , our restriction formula specializes to an easily computable rational sum which depends only on the gkm graph . . And you have already written the first three sentences of the full article: let @xmath5 be a compact torus with lie algebra @xmath6 and lattice @xmath7 . suppose that @xmath5 acts on a compact symplectic manifold @xmath8 with isolated fixed points and moment map @xmath9 , where @xmath10 is dual to @xmath6 . then @xmath11 where @xmath12 denotes the vector field on @xmath2 generated by the action and @xmath13 is defined by @xmath14 . here , @xmath15 is the natural pairing between @xmath10 and @xmath6 .. Please generate the next two sentences of the article

if @xmath16 is * generic * , that is , if @xmath17 for each weight @xmath18 in the symplectic representation @xmath19 for every @xmath20 in the fixed set @xmath21 , then @xmath22 is a morse function with critical set @xmath21 . given @xmath23 , the negative tangent bundle @xmath24 is a representation with no fixed sub - bundle .

Suppose that you have an abstract for a scientific paper: we study physics concerning the cosmological constant problem in the framework of effective field theory and suggest that a dominant part of dark energy can originate from gravitational corrections of vacuum energy , under the assumption that the classical gravitational fields do not couple to a large portion of the vacuum energy effectively , in spite of the coupling between graviton and matters at a microscopic level . our speculation is excellent with terascale supersymmetry . dark energy from gravitational corrections .45em 1.5 cm yugo abe@xmath0 , masaatsu horikoshi@xmath1 and yoshiharu kawamura@xmath1 1.5em @xmath2_graduate school of science and engineering , shimane university , _ + matsue 690 - 8504 , japan + @xmath3_department of physics , shinshu university , _ + matsumoto 390 - 8621 , japan 4.5em = 1.0em = 1.0em = 0.5em = 0.5em . And you have already written the first three sentences of the full article: the cosmological constant problem ( ccp ) is a biggest puzzle in particle physics @xcite , and consists of several pieces . the first piece is that the vacuum energy density @xmath4 can be the cosmological constant @xmath5 and various sources of @xmath4 exist , e.g. , a zero point energy of each particle and potential energies accompanied with phase transitions such as the breakdown of electroweak symmetry via higgs mechanism and the chiral symmetry breaking due to quark condensations . the second one is that @xmath4 can receive large radiative corrections including a cutoff scale .. Please generate the next two sentences of the article

the third one is that the experimental value of @xmath5 is estimated as @xmath6gev@xmath7 where @xmath8 is the newton constant , and @xmath9 . ] from the observation that the expansion of present universe is accelerating @xcite . the energy density defined by @xmath10 is referred as @xmath11dark energy density , and its existence has been a big mystery . the pieces of puzzle are not fitted in the framework of the einstein gravity and the standard model of particle physics .

Suppose that you have an abstract for a scientific paper: present and planned experiments motivate new theoretical study of properties of light unflavoured pseudoscalar meson decays . an overview including details on two - loop calculation in @xmath0 limit is given . chiral perturbation theory , radiative decay of @xmath1 , higher - order correction . And you have already written the first three sentences of the full article: we would like to study unflavoured decays of light neutral pseudoscalar mesons . this reduces the particle content to @xmath1 , @xmath2 and eventually @xmath3 , ruling out @xmath4 decays that violate hypercharge conservation and are suppressed by @xmath5 ( two - photon decays are further suppressed by @xmath6 compared to hadronic ones ) . standard model is thus reduced to qcd ( extended eventually only by qed corrections ) which is successfully described by an effective theory known as chiral perturbation theory ( chpt ) .. Please generate the next two sentences of the article

the @xmath1 meson being the lightest meson can not decay to other hadronic states . its dominant decay mode ( with more than 98% probability ) is @xmath7 and is connected with the adler - bell - jackiw triangle anomaly @xcite .

Suppose that you have an abstract for a scientific paper: we consider the hypothesis of a limiting minimal curvature in gravity as a way to construct a class of theories exhibiting late - time cosmic acceleration . guided by the minimal curvature conjecture ( mcc ) we are naturally lead to a set of scalar tensor theories in which the scalar is non - minimally coupled both to gravity and to the matter lagrangian . the model is compared to the lambda cold dark matter concordance model and to the observational data using the gold " sneia sample of riess et . al . ( 2004 ) . an excellent fit to the data is achieved . we present a toy model designed to demonstrate that such a new , possibly fundamental , principle may be responsible for the recent period of cosmological acceleration . observational constraints remain to be imposed on these models . dcpt-06/17 s l h . And you have already written the first three sentences of the full article: one of the most profound discoveries of observational physics is that the universe is accelerating in its expansion @xcite . there have been many attempts to explain this late - time acceleration , for example , a pure cosmological constant , dark energy associated with some new scalar field and modified gravitational theories , although all current models require some level of fine - tuning and none are considered to be a complete explanation . whatever is responsible for the current acceleration may arise from some completely new physical principle .. Please generate the next two sentences of the article

this is the possibility we consider in this paper . our goal is to construct a toy model that represents a late - time accelerating universe using a new , possibly fundamental , principle .

Suppose that you have an abstract for a scientific paper: most nuclear physics ranges from insensitive to relatively insensitive to many - nucleon forces . the dominant ingredient in calculations of nuclear properties is the nucleon - nucleon potential . three - nucleon forces nevertheless play an important role in nuclear physics because of the great precision of modern calculational methods for systems of relatively few nucleons . we explore the reasons why many - body forces are weak in nuclei by using a classification scheme for such forces that is based on dimensional power counting , which is used to organize chiral perturbation theory . an assessment will be made of how close we are to a `` standard '' three - nucleon force . recent advances in determining the significance of three - nucleon forces will also be discussed . . And you have already written the first three sentences of the full article: the turn of the century is a good time to assess the importance and impact of three - nucleon forces ( 3nfs ) on the development of the field of few - nucleon physics . it has been 67 years since wigner@xcite first raised the possibility that three - nucleon forces might be significant in the triton : `` @xmath0 one must assume a certain potential energy @xmath0 or a three - body force . '' it is significant that the triton had not yet been discovered , although he predicted it would be bound by nucleon - nucleon ( nn ) forces alone .. Please generate the next two sentences of the article

since that time we have relied on field - theoretic techniques , phenomenology , and sophisticated symmetry arguments to construct 3nfs , and the most modern and advanced experimental facilities have recently been used to validate these forces . in a very real sense we are fortunate that three - nucleon potentials are not too strong or too weak .

Suppose that you have an abstract for a scientific paper: the measurement of doppler velocity shifts in spectra is a ubiquitous theme in astronomy , usually handled by computing the cross - correlation of the signals , and finding the location of its maximum . this paper addresses the problem of the determination of wavelength or velocity shifts among multiple spectra of the same , or very similar , objects . we implement the classical cross - correlation method and experiment with several simple models to determine the location of the maximum of the cross - correlation function . we propose a new technique , _ self - improvement _ , to refine the derived solutions by requiring that the relative velocity for any given pair of spectra is consistent with all others . by exploiting all available information , spectroscopic surveys involving large numbers of similar objects may improve their precision significantly . as an example , we simulate the analysis of a survey of g - type stars with the sdss instrumentation . applying _ self - improvement _ refines relative radial velocities by more than 50% at low signal - to - noise ratio . the concept is equally applicable to the problem of combining a series of spectroscopic observations of the same object , each with a different doppler velocity or instrument - related offset , into a single spectrum with an enhanced signal - to - noise ratio . . And you have already written the first three sentences of the full article: the application of cross - correlation techniques to measure velocity shifts has a long history ( simkin 1972 , 1974 ; lacy 1977 ; tonry & davis 1979 ) , and with the advent of massive digital spectroscopic surveys of galaxies and stars , the subject has renewed interest . the recently completed sloan digital sky survey ( sdss ) has collected spectra for more than 600,000 galaxies and 90,000 quasars ( adelman - mccarthy et al . 2007 , york et al . 2000 ) .. Please generate the next two sentences of the article

the sdss has also obtained spectra for about 200,000 galactic stars , and it is now being extended at lower galactic latitudes by segue with at least as many spectra ( rockosi 2005 , yanny 2005 ) . another ongoing galactic survey , rave , is expected to collect high - resolution spectra for a million stars by 2011 ( steinmetz et al .

Suppose that you have an abstract for a scientific paper: recent experimental results on the partonic structure of the photon and on the color singlet exchange in strong interaction processes are reviewed . at the lep @xmath0 and hera @xmath1 colliders , complementary and consistent measurements have been achieved on the quark - gluon structure of quasi - real and virtual photons . at the hera @xmath1 and tevatron @xmath2 colliders , the quark - gluon configuration of the diffractive exchange is consistently found to have a large gluon component . the rate of diffractive interactions observed by the hera and tevatron experiments , however , is largely different and challenges explanation . # 1#2#3#4#1 * # 2 * ( # 3 ) # 4 @xmath3 @xmath4 desy-98 - 209b issn 0418 - 9833 + december 1998 * diffraction and low-@xmath5 physics + including two - photon physics * martin erdmann + universitt karlsruhe , engesserstr . 7 , d-76128 karlsruhe + e - mail : martin.erdmann@desy.de _ invited plenary talk at the xxix international conference on high energy physics , vancouver , b.c . canada ( 1998 ) _ . And you have already written the first three sentences of the full article: the motivation behind studying the structure of the photon results from the interest in understanding the formation of hadronic matter . permitted by the heisenberg uncertainty relation , the photon can fluctuate for some time into a quark anti - quark state . this fluctuation can be disturbed , e.g. , by an electron or proton probe which allows the density of quarks and gluons of the partonic state of the photon to be determined . at the lep @xmath0 and hera @xmath1 colliders ,. Please generate the next two sentences of the article

photons are emitted by the leptons which gives access to the partonic structure of almost real photons @xcite as well as highly virtual photons . the measurements to obtain information on the partonic state of the photons discussed here are 1 . the photon structure function from deep inelastic electron

Suppose that you have an abstract for a scientific paper: we present a new scheme for modeling the broad line region in active galactic nuclei . it involves photoionization calculations applied to a number of variable emission lines at _ all times_. we demonstrate how fitting all lines simultaneously provide strong constraints on several of the more important parameters , such as the density and column density , and the radial distribution of the emission line clouds . when applying the model to the seyfert 1 galaxy ngc 5548 , we are able to reconstruct the light curves of four emission - lines , in time and in absolute flux . we argue that the balmer line light curves , and possibly also the mgii@xmath02798 light curve , do not fit this scheme because of the limitations of present - day photoionization codes . we rule out models where the particle density scales as @xmath1 and favor models where it scales as @xmath2 . we can place lower limits on the column density at a distance of 10 ld , of @xmath3=10)@xmath4 @xmath5 , and limit the particle density to be in the range of 10@xmath6@xmath7@xmath8=10)@xmath710@xmath9 @xmath10 . . And you have already written the first three sentences of the full article: broad emission line regions ( blrs ) in active galactic nuclei ( agns ) have been the subject of extensive studies for more than two decades . such regions are not spatially resolved , and all the available information about their geometry is obtained from analysis of variable lines . it is well established that photoionization by the central radiation source is the main source of ionization and excitation of the blr gas . indeed , photoionization calculations , when applied to time - averaged spectra , can reasonably explain most of the observed line ratios ( for review and references see ferland , in these proceedings , and netzer 1990 ) . however , such time - averaged calculations contain little information about the spatial distribution of the gas .. Please generate the next two sentences of the article

extensive monitoring campaigns , during the last decade , have produced several high quality data sets . they include the time dependence of the multi - wavelength continuum , as well as the change in line fluxes and line profiles as a function of time ( for a review see , horne these proceedings , peterson 1993 , netzer & peterson 1997 ) .

Suppose that you have an abstract for a scientific paper: we define a volume limited sample of over 14,000 early - type galaxies ( etgs ) selected from data release six of the sloan digital sky survey . the density of environment of each galaxy is robustly measured . by comparing narrow band spectral line indices with recent models of simple stellar populations ( ssps ) we investigate trends in the star formation history as a function of galaxy mass ( velocity dispersion ) , density of environment and galactic radius . we find that age , metallicity and @xmath0-enhancement all increase with galaxy mass and that field etgs are younger than their cluster counterparts by @xmath1 . we find negative radial metallicity gradients for all masses and environments , and positive radial age gradients for etgs with velocity dispersion over @xmath2 . our results are qualitatively consistent with a relatively simple picture for etg evolution in which the low - mass halos accreted by a proto - etg contained not only gas but also a stellar population . this fossil population is preferentially found at large radii in massive etgs because the stellar accretions were dissipationless . we estimate that the typical , massive etg should have been assembled at @xmath3 . the process is similar in the cluster and the field but occurred earlier in dense environments . [ firstpage ] galaxies : elliptical and lenticular , cd , galaxies : formation , galaxies : abundances . And you have already written the first three sentences of the full article: observational determinations of the history of star formation in early - type galaxies ( hereafter etgs ) are of great importance because hierarchical models of galaxy formation make firm predictions for the relation between age , metallicity and @xmath0-enhancement as a function of mass . these scaling relations , plotted against the observational proxy for mass , the velocity dispersion ( hereafter @xmath4 ) , have been the focus of many recent studies of etgs ( annibali et al . 2007 , bernardi et al . , 2006. Please generate the next two sentences of the article

, de la rosa et al . 2007 , gallazzi et al . 2006 , jimenez et al .

Suppose that you have an abstract for a scientific paper: we study some generic properties of partially hyperbolic symplectic systems with 2d center . we prove that @xmath0 generically , every hyperbolic periodic point has a transverse homoclinic intersection for the maps close to a direct / skew product of an anosov diffeomorphism with a map on @xmath1 or @xmath2 . . And you have already written the first three sentences of the full article: let @xmath3 be a closed manifold and @xmath4 be a diffeomorphism on @xmath3 . a periodic point @xmath5 is said to be _ hyperbolic _ , if the linearization @xmath6 does nt admit any eigenvalue of norm 1 . associated to a hyperbolic periodic orbit are the _ stable _ and _ unstable manifolds _ @xmath7 of @xmath8 . a point in the intersection @xmath9 for another hyperbolic periodic point @xmath10. Please generate the next two sentences of the article

is called a _ heteroclinic intersection _ ( a _ homoclinic intersection _ if @xmath11 ) . note that the intersection @xmath9 may not be _ transverse _