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9,600 | Suppose that you have an abstract for a scientific paper: we compute next - to - next - to - leading order qcd corrections to the gluon - induced production cross section of higgs boson pairs in the large top quark mass limit using the soft - virtual approximation . in the limit of infinitely - heavy top quark
we confirm the results in the literature .
we add two more expansion terms in the inverse top quark mass to the @xmath0 result .
since the @xmath1 expansion converges poorly , we try to improve on it by factorizing the exact leading order cross section .
we discuss two ways of doing that and conclude that the finite top quark mass effects shift the cross section at most by about 10% at next - to - leading order and by about 5% at next - to - next - to - leading order .
pacs numbers : 14.80.bn , 12.38.bx , 14.65.ha .
And you have already written the first three sentences of the full article: in the coming years , one of the main tasks in particle physics is the understanding of the mechanism of the electroweak symmetry breaking .
after the experimental determination of the higgs boson mass , the higgs potential is fully fixed in the standard model .
however , it is very important to independently measure the self - coupling of the higgs boson , which can be obtained from studying the production of higgs boson pairs . since the corresponding cross section is @xmath2 times smaller than the one for single higgs boson production , higgs boson pair production poses a challenging problem for the lhc , even after the luminosity upgrade around 2020 ..
Please generate the next two sentences of the article | there are a number of phenomenological analyses which investigate the possibility to extract the self coupling from cross section measurements .
first studies have been performed more than 15 years ago @xcite . |
9,601 | Suppose that you have an abstract for a scientific paper: in nuclear and particle physics one is often faced with problems where perturbation theory is not applicable .
an example of this is the description of bound states .
therefore , an exact solution of field theory to all orders is an unavoidable and interesting problem .
path integrals provide a framework for exact solutions in field theory . in this talk
i will present an economical method of evaluating path integrals using the feynman - schwinger representation ( fsr ) . .
And you have already written the first three sentences of the full article: the basic idea in the feynman - schwinger representation is to replace path integrals over quantum fields with path integrals over particle trajectories .
the step of going from field configurations to particle trajectories dramatically reduces the number of degrees of freedom . in this talk we present analytic and numerical applications of feynman - schwinger representation @xcite to nonperturbative problems
the first applictaion is the calculation of 1-body propagator in massive scalar qed ..
Please generate the next two sentences of the article | the second application involves the calculation of 2-body bound state masses in scalar @xmath0 interaction .
massive scalar qed in 0 + 1 dimension is a simple interaction that enables one to obtain a fully analytical result for the dressed and bound state masses within the fsr approach . in 0 + 1 dimension |
9,602 | Suppose that you have an abstract for a scientific paper: we investigate the location and nature of the para - ferro transition of interacting electrons in dispersionless bands using the example of the hubbard model on the tasaki lattice .
this case can be analyzed as a geometric site - percolation problem where different configurations appear with nontrivial weights .
we provide a complete exact solution for the 1d case and develop a numerical algorithm for the 2d case . in two dimensions
the paramagnetic phase persists beyond the uncorrelated percolation point , and the grand - canonical transition is via a first - order jump to an _ unsaturated _ ferromagnetic phase . _
introduction._the interplay of the coulomb interaction with the pauli principle was already recognized by heisenberg @xcite to give rise to a ferromagnetic exchange interaction , also encoded in hund s rule about aligned spins in a partially filled shell . for a many - body system of correlated electrons with a flat band ,
when the interaction energy completely dominates over the kinetic energy , the ferromagnetic instability is one of the few problems for which exact results are available , albeit for a restricted range of fillings @xcite .
flat band systems are receiving a great deal of attention right now , in particular with the view of realizing new many - body phases there ( see @xcite and references therein ) ; in this context , the possibility of ferromagnetism as a many - body instability is also being considered @xcite .
it is therefore timely to provide a detailed study of the phase diagram and the critical properties of this form of magnetism : we analyze a flat - band ferromagnet with an on - site hubbard interaction of strength @xmath0 . for @xmath1 ,
any state involving electrons occupying the flat band only is trivially a ground state .
crucially , this degeneracy is only partially lifted when a repulsive @xmath2 is switched on .
first , since the flat band permits well - localized real - space electronic wave functions , at low density electrons can....
And you have already written the first three sentences of the full article: these can be most transparently studied by considering the hubbard model , which describes electrons hopping on a lattice which interact with each other via an on - site repulsion .
the hubbard hamiltonian reads @xmath76 in standard notations .
let us consider the tasaki lattice @xcite ( fig . [ fig01s ] ) as a representative for a 2d system with a dispersionless ( flat ) band ..
Please generate the next two sentences of the article | tasaki s lattice decoration @xcite can be performed in arbitrary dimension ( and also for other lattices ) .
this allows a direct comparison of 1d and 2d . for the lowest - energy one - electron band to be completely dispersionless , the two relevant hopping integrals obey the relation @xmath77 , where @xmath71 is the coordination number of the underlying lattice . |
9,603 | Suppose that you have an abstract for a scientific paper: we find that multidimensional determinants `` hyperdeterminants '' , related to entanglement measures ( the so - called concurrence or 3-tangle for the 2 or 3 qubits , respectively ) , are derived from a duality between entangled states and separable states . by means of the hyperdeterminant and its singularities ,
the single copy of multipartite pure entangled states is classified into an onion structure of every closed subset , similar to that by the local rank in the bipartite case .
this reveals how inequivalent multipartite entangled classes are partially ordered under local actions . in particular , the generic entangled class of the maximal dimension , distinguished as the nonzero hyperdeterminant , does not include the maximally entangled states in bell s inequalities in general ( e.g. , in the @xmath0 qubits ) , contrary to the widely known bipartite or @xmath1-qubit cases .
it suggests that not only are they never locally interconvertible with the majority of multipartite entangled states , but they would have no grounds for the canonical @xmath2-partite entangled states .
our classification is also useful for the mixed states . .
And you have already written the first three sentences of the full article: entanglement is the quantum correlation exhibiting nonlocal ( nonseparable ) properties .
it is supposed to be never strengthened , on average , by local operations and classical communication ( locc ) .
in particular , entanglement in _.
Please generate the next two sentences of the article | multi_-parties is of fundamental interest in quantum many - body theory @xcite , and makes quantum information processing ( qip ) , e.g. , distillation protocol , more efficient than that relying on entanglement only in _
two_-parties @xcite . here , we classify and characterize the multipartite entanglement which has yet to be understood , compared with the bipartite one . for the single copy of bipartite pure states on @xmath3 , |
9,604 | Suppose that you have an abstract for a scientific paper: we use distributed computing tools to provide a new perspective on the behavior of cooperative biological ensembles .
we introduce the _ ants nearby treasure search ( ants ) _ problem , a generalization of the classical cow - path problem @xcite , which is relevant for collective foraging in animal groups . in the ants problem ,
@xmath0 identical ( probabilistic ) agents , initially placed at some central location , collectively search for a treasure in the two - dimensional plane .
the treasure is placed at a target location by an adversary and the goal is to find it as fast as possible as a function of both @xmath0 and @xmath1 , where @xmath1 is the distance between the central location and the target .
this is biologically motivated by cooperative , central place foraging , such as performed by ants around their nest . in this type of search
there is a strong preference to locate nearby food sources before those that are further away .
we focus on trying to find what can be achieved if communication is limited or altogether absent . indeed , to avoid overlaps agents must be highly dispersed making communication difficult .
furthermore , if the agents do not commence the search in synchrony , then even initial communication is problematic .
this holds , in particular , with respect to the question of whether the agents can communicate and conclude their total number , @xmath0 .
it turns out that the knowledge of @xmath0 by the individual agents is crucial for performance .
indeed , it is a straightforward observation that the time required for finding the treasure is @xmath2 , and we show in this paper that this bound can be matched if the agents have knowledge of @xmath0 up to some constant approximation .
we present a tight bound for the competitive penalty that must be paid , in the running time , if the agents have no information about @xmath0 .
specifically , this bound is slightly more than logarithmic in the number of agents .
in addition , we give a lower bound for the....
And you have already written the first three sentences of the full article: the universality of search behaviors is reflected in multitudes of studies in different fields including control systems , distributed computing and biology .
we use tools from distributed computing to study a biologically inspired scenario in which a group of agents , initially located at one central location , cooperatively search for treasures in the plane .
the goal of the search is to locate nearby treasures as fast as possible and at a rate that scales well with the number of participating agents . a variety of animal species search for food around a central location that serves the search s initial point , final destination or both @xcite ..
Please generate the next two sentences of the article | this central location could be a food storage area , a nest where offspring are reared or simply a sheltered or familiar environment .
central place foraging holds a strong preference to locating nearby food sources before those that are further away . |
9,605 | Suppose that you have an abstract for a scientific paper: we review the basic properties of the haldane phase in spin-1 heisenberg antiferromagnetic chains , including its persistence in quasi - one - dimensional geometries . using large - scale numerical simulations , we map out the phase diagram for a realistic model applicable to experimental haldane compounds .
we also investigate the effect of different chain coupling geometries and confirm a general mean field universality of the critical coupling times the coordination number of the lattice .
inspired by the recent development of characterization of symmetry protected topological states , of which the haldane phase of spin-1 heisenberg antiferromagnetic chain is a preeminent example , we provide direct evidence that the quasi - one - dimensional haldane phase is indeed a non - trivial symmetry protected topological state . .
And you have already written the first three sentences of the full article: low dimensional interacting spin systems have long been a laboratory for the discovery of novel quantum states of matter . enhanced quantum fluctuations due to reduced dimensionality
enable the appearance of multiple quantum phases with unique characteristics driven by the interplay between strong interactions , external ( e.g. , pressure and magnetic field ) and internal ( e.g. , crystal field effects ) potentials and lattice geometry that are suppressed in higher dimensions . the relative simplicity of the microscopic models facilitates the development of exact analytical solutions in many cases and powerful field theoretic and computational approaches in others providing greater insight into the emergence of these complex phases and their physical properties .
concurrent rapid advances in the synthesis and characterization of low - dimensional quantum magnets have kept the study of these systems one of the most active frontiers in condensed matter physics ( see landee and turnbull@xcite for a recent pedagogical review ) ..
Please generate the next two sentences of the article | one of the most remarkable results in the study of quantum spin models one that substantially enhanced our understanding of long range order in quantum many body systems is the pioneering work by haldane.@xcite by studying the non - linear sigma model in ( 1 + 1 ) dimensions , haldane conjectured that the ground state of the one - dimensional ( 1d ) heisenberg antiferromagnet ( hafm ) has gapless excitations for half - odd integer spins , whereas that for integer spins is separated from all excited states by a finite spin gap ( haldane gap ) .
haldane s conjecture has inspired numerous theoretical studies of integer spins in low dimensions , primarily @xmath0 spins where the haldane phase is most robust . |
9,606 | Suppose that you have an abstract for a scientific paper: this paper attempts multi - label classification by extending the idea of independent binary classification models for each output label , and exploring how the inherent correlation between output labels can be used to improve predictions . logistic regression , naive bayes , random forest , and svm models were constructed , with svm giving the best results : an improvement of 12.9% over binary models was achieved for hold out cross validation by augmenting with pairwise correlation probabilities of the labels . .
And you have already written the first three sentences of the full article: multi - label classification is the set of classification problems where the output vector has a variable length .
the average number of labels per review varies across datasets , and in general is a function of the semantics of the text rather than the syntax .
the learning algorithm needs to estimate the number of labels and make the correct predictions ..
Please generate the next two sentences of the article | + previously multi - label classification problems were solved using problem transformation techniques ( converting the problem into binary classification problems per output label ) , or by adapting the algorithm to directly perform multi - label classification @xcite . this paper extracts correlation information between labels and factors the joint probabilities into the model . +
given large datasets of product reviews from amazon and twitter and manually labelled multi - label classifications for each ( ground truth ) , the algorithm aims to predict all classifications for a review @xcite . |
9,607 | Suppose that you have an abstract for a scientific paper: a known ` sticky - hard - sphere ' model , defined starting from a hard - sphere - yukawa potential and taking the limit of infinite amplitude and vanishing range with their product remaining constant , is shown to be ill - defined .
this is because its hamiltonian ( which we call shs2 ) leads to an _ exact _ second virial coefficient which _ diverges _ , unlike that of baxter s original model ( shs1 ) .
this deficiency has never been observed so far , since the linearization implicit in the ` mean spherical approximation ' ( msa ) , within which the model is analytically solvable , partly _ masks _ such a pathology . to overcome this drawback and retain some useful features of shs2
, we propose both a new model ( shs3 ) and a new closure ( ` modified msa ' ) , whose combination yields an analytic solution formally identical with the shs2-msa one .
this mapping allows to recover many results derived from shs2 , after a re - interpretation within a correct framework .
possible developments are finally indicated . .
And you have already written the first three sentences of the full article: in a seminal series of papers @xcite baxter first introduced the concept of the so - called ` sticky hard sphere ' ( shs ) models , as the simplest - albeit crude - modelization for real fluids of spherical particles with a strong surface adhesion . in baxter s original formulation @xcite and its extension to the multi - component case @xcite ( both hereafter referred to as shs1 model )
the pair potential contains - in addition to a hard sphere ( hs ) repulsion - a infinitely deep and narrow attractive square - well , obtained according to a particular limiting procedure ( baxter s ` sticky limit ' ) that keeps the second virial coefficient finite baxter68 .
although this model appears rather pathological at first sight , it includes a number of interesting features which justify its wide popularity ..
Please generate the next two sentences of the article | first , the ornstein - zernike ( oz ) integral equation of the statistical - mechanical theory of fluids can be analytically solved for it within the _ percus - yevick _ ( py ) approximation and the solution exhibits a gas - liquid transition @xcite .
second , baxter s model has already proven to be appropriate for describing some properties of colloidal suspensions , micelles , microemulsions and protein solutions with short - range interactions as well as some aspects of adsorption , flocculation and percolation phenomena , solvent - mediated forces , ionic mixtures , solutions with a small degree of size polydispersity and fluids of chain - like molecules ( for an illustrative , albeit not exhaustive , list of references , see @xcite ) . |
9,608 | Suppose that you have an abstract for a scientific paper: we investigate scalar and tensor fields in the brane model solution for the 5d space - time with standing gravitational waves in the bulk and show that even in the case of increasing warp factor there exist normalizable zero modes localized on the brane . 0.3 cm pacs numbers : 04.50.-h , 11.25.-w , 11.27.+d 0.5 cm .
And you have already written the first three sentences of the full article: the scenario where our world is associated with a brane embedded in a higher dimensional space - time with non - factorizable geometry @xcite has attracted a lot of interest with the aim of solving several open questions in modern physics . most of these models were realized as time independent field configurations .
however , there have appeared several braneworld models that assumed time - dependent metrics and fields @xcite .
here we consider the braneworld scenario with non - stationary metric coefficients recently proposed in @xcite ..
Please generate the next two sentences of the article | the braneworld is generated by 5d standing gravitational waves coupled to a phantom - like scalar field in the bulk .
a key requirement for realizing the braneworld idea is that the various bulk fields be localized on the brane . for reasons of economy and avoidance of charge universality obstruction |
9,609 | Suppose that you have an abstract for a scientific paper: the status of conventional baryon flux - tubes and hybrid baryons is reviewed .
recent surprises are that a model prediction indicates that hybrid baryons are very weakly produced in glue - rich @xmath0 decays , and an analysis of electro - production data concludes that the roper resonance is not a hybrid baryon . the baryon decay flux - tube overlap has been calculated in the flux - tube model , and is discussed here . the behavior of the overlap follows nave expectations . .
And you have already written the first three sentences of the full article: comprehensive reviews on baryon flux - tubes and hybrid baryons are available .
@xcite here developments since the last review in 2002 are summarized .
_ baryon flux - tube : _ the consensus in quenched lattice qcd is that the baryon potential at sufficient distances is best described by the sum of a coulomb , y - shaped confinement , and constant term ..
Please generate the next two sentences of the article | @xcite this statement is independent of the lattice operator , and hence physical .
@xcite the difference with abelian projected full lattice qcd is small . |
9,610 | Suppose that you have an abstract for a scientific paper: iso - electric point(iep ) is the ph , at which the @xmath0 potential is measured to be zero .
the occurrence of iep has been understood due to the neutralization of surface charge density ( scd ) at the solid - liquid interface . in this work
, we use the potential trap model to study the sources of the surface charge density at verious pc and ph , by taking the water - silica system as an example .
it is revealed that in the case of @xmath1 , the scd is mainly originated from the dissociation of water molecules . and the bulk ions trapped at the interface can dominate the scd when @xmath2 . due to the mass action law , the dissociation of water molecules is suppressed at the ph close to iep , leading to a zero surface charge density . in this way , zero @xmath0 potential is obtained at the iep .
it has also been obtained that the increase of the salt concentration in the water can decrease the @xmath0 potential , but increase the surface charge density .
pacs numbers : : 47.57.jd , 47.56.+r , 68.08.-p , 66.10.ed , 73.25.+i .
And you have already written the first three sentences of the full article: electrokinetics(ek ) in fluid is a classical subject defined as the study on the interaction of ions with the solid interface , and the dynamics of ions in fluid under external fields @xcite .
the roots of the ek study are very broad and can be stemmed from various disciplines for decades , such as chemistry , biology , physics , and material sciences . with the development of nano technologies , the structure scale used to confine liquid can be narrowed from micro to nano .
the increase of the surface - to - volume ratio in low dimensional structures leads to new ek behaviors @xcite ..
Please generate the next two sentences of the article | those new ek phenomena can be applied to molecular manipulation , drug mixing , and electro - osmosis , etc , which stimulates the ek study experiencing a strong revival @xcite .
+ it is well known that the ions at the liquid - solid interface attract counter ions to form electric double layers(edl ) in liquid @xcite . as an example of water at @xmath3 , |
9,611 | Suppose that you have an abstract for a scientific paper: we present a first - principles study of model domain walls ( dws ) in prototypic ferroelectric pbtio@xmath0 . at high temperature
the dw structure is somewhat trivial , with atoms occupying high - symmetry positions .
however , upon cooling the dw undergoes a symmetry - breaking transition characterized by a giant dielectric anomaly and the onset of a large and switchable polarization .
our results thus corroborate previous arguments for the occurrence of ferroic orders at structural dws , providing a detailed atomistic picture of a temperature - driven dw - confined transformation . beyond its relevance to the field of ferroelectrics ,
our results highlight the interest of these dws in the broader areas of low - dimensional physics and phase transitions in strongly - fluctuating systems .
the structural domain walls ( dws ) occurring in ferroelectric ( fe ) and ferroelastic ( fs ) materials have become a focus of attention .
recent studies show that the dws can present a variety of properties , from conductive @xcite and optical @xcite to magnetic @xcite , that differ from those of the neighboring domains , which suggests that they could be the active element in nano - technological applications @xcite . elucidating the dw behavior
poses major experimental challenges , and the origin of most of the newly discovered effects remains unclear .
in fact , we still lack a detailed structural and dynamical picture of the dws , and in many cases we can only speculate about the structure property relationships at work within them .
hence , there is a pressing need for predictive theoretical studies tackling the dws at an atomistic level and at the relevant conditions of temperature , etc .
the dw structure , and even the possible occurrence of dw - confined ferroic orders , have been discussed theoretically for decades , usually in the framework of continuum ginzburg - landau or phenomenological model theories @xcite .
materials with competing structural instabilities have been a focus....
And you have already written the first three sentences of the full article: in the following we describe the simulation methods employed as well as various technicalities pertaining to the calculation of some quantities
. we also comment on the determination and quantitative accuracy of the temperature at which the domain wall - confined ferroelectric transition takes place , and on previous first - principles literature on the dws in pbtio@xmath0 .
for most simulations we used the first - principles model for pto described in ref . , where it is labeled `` @xmath3 '' ..
Please generate the next two sentences of the article | this model can be viewed as a taylor series of the energy , around the ideal cubic perovskite structure , as a function of all possible atomic distortions and strains .
the series was truncated at 4th order and only pairwise interaction terms were included . |
9,612 | Suppose that you have an abstract for a scientific paper: we find that the density dependence of the glass transition temperature of lennard - jones ( lj ) and weeks - chandler - andersen ( wca ) systems can be predicted from properties of the zero - temperature ( @xmath0 ) glasses . below a crossover density @xmath1 , lj and
wca glasses show different structures , leading to different vibrational properties and consequently making lj glasses more stable with higher glass transition temperatures than wca ones . above @xmath1 ,
structural and vibrational quantities of the @xmath0 glasses show scaling collapse . from scaling relations and dimensional analysis
, we predict a density scaling of the glass transition temperature , in excellent agreement with simulation results .
we also propose an empirical expression of the glass transition temperature using structural and vibrational properties of the @xmath0 glasses , which works well over a wide range of densities . according to the theory of liquids ,
repulsive particle interaction determines the structure of dense liquids , while attraction acts as a perturbation @xcite .
the perturbative role of attraction has been questioned by recent simulations and experiments through the fact that a glass former with attraction can exhibit slower dynamics and consequently have a higher glass transition temperature than that with purely repulsive interaction even though their structures are similar @xcite .
recent theoretical approaches such as the mode coupling theory have failed to explain such nonperturbative effects of attraction from the liquid side above the glass transition temperature @xcite .
alternatively , some dynamical behaviors of supercooled liquids @xcite can be viewed from the glass side .
for instance , recent studies have shown that the heterogeneous dynamics of supercooled liquids and the glass transition temperature to a great extent reflect the quasi - localized nature of low - frequency normal modes of vibration of the zero - temperature ( @xmath0 ) glasses @xcite .
can we also....
And you have already written the first three sentences of the full article: @figure#1fig . s@xmath114
( a ) pair distribution function of @xmath31 particles @xmath72 , ( b ) density of vibrational states @xmath73 , and ( c ) participation ratio @xmath74 of the @xmath0 wca glasses generated from equilibrated states at different initial temperatures .
the density @xmath2 is @xmath115 ..
Please generate the next two sentences of the article | the legend shows the values of the initial temperatures.,scaledwidth=45.0% ] ( a ) intermediate scattering function @xmath116 for a particles of wca liquids with @xmath117 .
the density @xmath2 is @xmath115 . from the left to the right , |
9,613 | Suppose that you have an abstract for a scientific paper: the magnetic field dependence of the magnetisation ( @xmath0 ) and the temperature dependence of the ac susceptibility ( @xmath1 ) of cepd@xmath2rh@xmath3 single crystals with @xmath4 are analysed within the frame of the quantum griffiths phase scenario , which predicts @xmath5 and @xmath6 with @xmath7 .
all @xmath0 vs @xmath8 and @xmath9 vs @xmath10 data follow the predicted power - law behaviour .
the parameter @xmath11 , extracted from @xmath12 , is very sensitive to the rh content @xmath13 and varies systematically with @xmath13 from -0.1 to 0.4 .
the value of @xmath11 , derived from @xmath14 measurements on a cepd@xmath15rh@xmath16 single crystal , seems to be rather constant , @xmath17 , in a broad range of temperatures between 0.05 and 2 k and fields up to about 10 t. all observed signatures and the @xmath11 values are thus compatible with the quantum griffiths scenario . .
And you have already written the first three sentences of the full article: ce- and yb - based @xmath18-electron kondo - lattice ( kl ) systems have shown the most drastic forms of non - fermi - liquid ( nfl ) behaviour @xcite . in these heavy - fermion ( hf ) materials ,
the ground state sensitively depends on the balance between two competing interactions , which are both determined by the strength of the @xmath19-conduction electron hybridisation @xmath20 : whereas the kondo interaction leads to a screening of the local moments below a kondo temperature @xmath21 , resulting in a paramagnetic ( pm ) ground state with itinerant @xmath19-electrons , the indirect exchange coupling ( rkky interaction ) can mediate long - range magnetic ordering @xcite .
+ one of the explanations for such nfl phenomena is the presence of a quantum critical point ( qcp ) at a particular @xmath22 : if the transition temperature @xmath23 of the long - range magnetic order is continuously shifted to zero by an external parameter @xmath24 , e.g. pressure , magnetic field or chemical substitution , a @xmath25 order quantum phase transition ( qpt ) takes place at @xmath26 and @xmath27 , to which a qcp is associated . here ,.
Please generate the next two sentences of the article | the typical length and time scales of order parameter fluctuations diverge when approaching the transition point .
these fluctuations are believed to be responsible for the observed nfl corrections to the fl prediction for the heat capacity @xmath28 , magnetic susceptibility @xmath29 , electrical resistivity @xmath30 etc . |
9,614 | Suppose that you have an abstract for a scientific paper: we report our experience of the optimization of the lattice qcd codes for the new opteron cluster at desy hamburg , including benchmarks .
details of the optimization using sse / sse2 instructions and the effective use of prefetch instructions are discussed . .
And you have already written the first three sentences of the full article: lattice qcd is a powerful method to study quantum chromodynamics ( qcd ) in a nonperturbative way . in lattice qcd
, a path integral is directly evaluated on a discrete space - time lattice by means of the monte carlo method . as computer technology advances pc clusters
can also be used for lattice qcd simulations as well as a number of commercial supercomputers ..
Please generate the next two sentences of the article | since lattice qcd simulations demand huge computer power , it is very important to optimize the simulation codes so as to exploit the full potential of the processor .
thus we optimize the hot spots of the codes such as the operation of a dirac operator to a spinor ( referred as @xmath0 hereafter ) and linear algebra of spinors , e.g. * @xmath1 : scalar product of two spinors * @xmath2 : norm square of a spinor * @xmath3 : add two spinors with a constant factor and assign the result to one of the source spinors in the simulation , a spinor is defined as a vector with 12 complex components on each grid point ( site ) of the lattice , and a gauge field is defined as a complex @xmath4 matrix on a link , which connects nearest neighbor sites . |
9,615 | Suppose that you have an abstract for a scientific paper: recent studies show the importance of the star formation feedback in changing the energetic and structure of galaxies .
dissecting the physics of the feedback is hence crucial to understand the evolution of galaxies .
full polarization radio continuum surveys can be ideally performed to trace not only star formation but also the energetic components of the interstellar medium ( ism ) , the magnetic fields and cosmic ray electrons . using the ska precursors
, we investigate the effect of the massive star formation on the ism energy balance in nearby galaxies .
our multi - scale and multi - frequency surveys show that cosmic rays are injected in star forming regions and lose energy propagating away from their birth place . due to the star formation feedback ,
cosmic ray electron population becomes younger and more energetic .
star formation also amplifies the turbulent magnetic field inserting a high pressure which is important in energy balance in the ism and structure formation in the host galaxy . .
And you have already written the first three sentences of the full article: to understand the evolution and appearance of galaxies it is crucial to study the ism / star formation interplay in galaxies .
most of our information about the ism relates to its massive component , the gas and its various phases .
its interplay with star formation can be addressed through the famous kennicutt - schmidt relation ( schmidt 1959 , kennicutt 1998 ) between the rate of star formation and the gas density ..
Please generate the next two sentences of the article | the herschel and spitzer space telescopes have made major breakthroughs in this area , by mapping the emission from dust and the gas content of galaxies .
however , not much is known about the connection of star formation and the most energetic ism components , the cosmic rays and magnetic fields , and their role in structure formation in galaxies . as an extinction - free tracer of star formation |
9,616 | Suppose that you have an abstract for a scientific paper: in this paper , we propose two subspace - projection - based precoding schemes , namely , full - projection ( fp)- and partial - projection ( pp)-based precoding , for a cognitive radio multiple - input multiple - output ( cr - mimo ) network to mitigate its interference to a primary time - division - duplexing ( tdd ) system .
the proposed precoding schemes are capable of estimating interference channels between cr and primary networks , and incorporating the interference from the primary to the cr system into cr precoding via a novel sensing approach .
then , the cr performance and resulting interference of the proposed precoding schemes are analyzed and evaluated . by fully projecting the cr transmission onto a null space of the interference channels ,
the fp - based precoding scheme can effectively avoid interfering the primary system with boosted cr throughput . while , the pp - based scheme is able to further improve the cr throughput by partially projecting its transmission onto the null space . + _ * index terms * _ cognitive radio , interference mitigation , mimo , precoding . .
And you have already written the first three sentences of the full article: a cognitive radio ( cr ) @xcite@xcite system may coexist with a primary network on an either interference - free or interference - tolerant basis @xcite . for the former case
, the cr system only exploits the unused spectra of the primary network . while , for the latter case , the cr system is allowed to share the spectra assigned to primary network under the condition that it must not impose detrimental interference on the primary network .
therefore , the interference from the cr network to the primary system should be carefully managed and cancelled in order to protect the operation of the primary system . various interference mitigation ( i m ).
Please generate the next two sentences of the article | techniques applicable to cr networks have been reported in @xcite . as for multiple - antenna cr networks , transmit beamforming ( for single - data - stream transmission ) @xcite@xcite or precoding ( for multiple - data - stream transmission ) @xcite@xcite is an effective approach to proactively cancel interference from cr transmitters to the primary network . on one hand , it steers the cr transmission to avoid interfering with the primary network . on the other hand
, it exploits the diversity or the multiplexing gain of the multiple - antenna cr system to enhance the reliability or efficiency of the cr system . |
9,617 | Suppose that you have an abstract for a scientific paper: this work introduces microlocal compactness forms ( mcfs ) as a new tool to study oscillations and concentrations in @xmath0-bounded sequences of functions .
decisively , mcfs retain information about the location , value distribution , and direction of oscillations and concentrations , thus extending at the same time the theories of ( generalized ) young measures and h - measures . in @xmath0-spaces oscillations and concentrations
precisely discriminate between weak and strong compactness , and thus mcfs allow one to quantify the difference in compactness .
the definition of mcfs involves a fourier variable , whereby also differential constraints on the functions in the sequence can be investigated easily a distinct advantage over young measure theory .
furthermore , pointwise restrictions are reflected in the mcf as well , paving the way for applications to tartar s framework of compensated compactness ; consequently , we establish a new weak - to - strong compactness theorem in a `` geometric '' way . after developing several aspects of the abstract theory , we consider three applications : for lamination microstructures ,
the hierarchy of oscillations is reflected in the mcf .
the directional information retained in an mcf is harnessed in the relaxation theory for anisotropic integral functionals .
finally , we indicate how the theory pertains to the study of propagation of singularities in certain systems of pdes .
the proofs combine measure theory , young measures , and harmonic analysis .
msc ( 2010 ) : 28b05 ( primary ) ; 35b05 , 35a27 , 49j45 , 35l67 .
keywords : microlocal compactness form , mcf , oscillation , concentration , microlocal analysis , relaxation , microstructure , laminate , compensated compactness , hyperbolic system , propagation of singularities . date : ( version 3.0 ) . .
And you have already written the first three sentences of the full article: one of the major challenges in the analysis of nonlinear pdes is to understand oscillations and concentrations in weakly converging sequences of functions since these phenomena distinguish weak from strong convergence in @xmath1-spaces . in its most simple form , this observation is already expressed in vitali s classical convergence theorem , by which a norm - bounded , non - oscillating ( contained in the requirement of convergence in measure ) , non - concentrating ( equiintegrable ) sequence is seen to converge strongly .
this connection between `` abstract '' compactness and `` concrete '' oscillation and concentration effects also supports the view that questions of compactness have a `` physical '' meaning and should be studied for their own sake , cf .
@xcite ..
Please generate the next two sentences of the article | another motivation for such a study is that often sequences of interest are constrained by a linear differential constraint ( curl - freeness for a sequence of gradients for instance ) and/or pointwise constraints .
then , compensated compactness theory , see for example @xcite , considers whether these additional restrictions allow one to improve weak to strong compactness ; in fact , in this vein , the term `` compensated compactness '' should probably be replaced by `` compactness by compensation '' ( which is also closer to the french original `` compacit par compensation '' ) , but we here stick to the more conventional terminology . at the heart of this investigation |
9,618 | Suppose that you have an abstract for a scientific paper: the dynamics of dislocation assemblies in deforming crystals indicate the emergence of collective phenomena , intermittent fluctuations and strain avalanches . in polycrystalline materials ,
the understanding of plastic deformation mechanisms depends on grasping the role of grain boundaries on dislocation motion . here
the interaction of dislocations and elastic , low angle grain boundaries is studied in the framework of a discrete dislocation representation .
we allow grain boundaries to deform under the effect of dislocation stress fields and compare the effect of such a perturbation to the case of rigid grain boudaries .
we are able to determine , both analytically and numerically , corrections to dislocation stress fields acting on neighboring grains , as mediated by grain boundary deformation .
finally , we discuss conclusions and consequences for the avalanche statistics , as observed in polycrystalline samples . .
And you have already written the first three sentences of the full article: recent advances in experimental techniques have allowed the redefinition of the once supposedly well - understood problem of crystal plasticity . in spite of the traditional picture of a smooth fluid - like motion , acoustic emission ( ae )
measurements on deforming ice crystals @xcite as well as more recent compression tests on metallic specimens @xcite have during the last decade made it clear that plastic deformation of crystalline materials proceeds as a heterogeneous and intermittent adjustment to applied external drives . such intermittence in plastic deformation had been for long observed @xcite and dismissed as considered unworthy of serious consideration .
the recent discoveries challenge this picture since that heterogeneity appears to take over through the emergence of a burst - like scale - free behavior ..
Please generate the next two sentences of the article | plastic deformation is found to develop through strain avalanches , characterized by power law distributed sizes and energy emissions .
slip motion is found to follow fractal patterns @xcite and deformed specimens exhibit self - affine surfaces @xcite . |
9,619 | Suppose that you have an abstract for a scientific paper: we construct open book structures on moment - angle manifolds and give a new construction of examples of contact manifolds in arbitrarily large dimensions .
* key words : * open book decomposition , moment - angle manifolds , contact structures . .
And you have already written the first three sentences of the full article: the topology of generic intersections of quadrics in @xmath0 of the form : @xmath1 where @xmath2 , @xmath3 has been studied for many years : for @xmath4 they are diffeomorphic to a triple product of spheres or to the connected sum of sphere products ( @xcite , @xcite ) ; for @xmath5 this is no longer the case ( @xcite , @xcite ) but there are large families of them which are again connected sums of spheres products ( @xcite ) .
+ let @xmath6 .
the generic condition , known as _ weak hyperbolicity _ and equivalent to regularity , is the following : + _ if @xmath7 has @xmath8 or fewer elements then the origin is not in the convex hull of the @xmath9 with @xmath10 . _.
Please generate the next two sentences of the article | + a crucial aspect of these varieties is that they admit natural group actions .
all of them admit @xmath11 actions . |
9,620 | Suppose that you have an abstract for a scientific paper: fluorine ( @xmath0f ) abundances are derived in a sample of 6 bulge red giants in baade s window .
these giants span a factor of 10 in metallicity and this is the first study to define the behavior of @xmath0f with metallicity in the bulge .
the bulge results show an increase in f / o with increasing oxygen .
this trend overlaps what is found in the disk at comparable metallicities , with the most oxygen - rich bulge target extending the disk trend .
the increase in f / o in the disk arises from @xmath0f synthesis in both asymptotic giant branch ( agb ) stars and metal - rich wolf - rayet ( wr ) stars through stellar winds .
the lack of an s - process enhancement in the most fluorine - rich bulge giant in this study , suggests that wr stars represented a larger contribution than agb stars to @xmath0f production in the bulge when compared to the disk .
if this result for fluorine is combined with the previously published overall decline in the o / mg abundance ratios in metal - rich bulge stars , it suggests that wr winds played a role in shaping chemical evolution in the bulge .
one star in this study exhibits a very low value of f / o while having a large o - abundance ; this chemical mixture can be understood if this star formed from gas that was enriched by metal - poor core - collapse supernovae and may indicate that chemical evolution in the bulge was inhomogeneous . .
And you have already written the first three sentences of the full article: understanding how chemical evolution has proceeded in the galactic bulge can provide clues for models of bulge formation and evolution .
it is not known , for example , whether the milky way bulge was formed rapidly in a single collapse or via secular dynamical evolution driven by the disk .
certain elemental abundance ratios can be used to infer timescales for chemical enrichment within a particular stellar population ..
Please generate the next two sentences of the article | the most studied of these ratios involves comparing the abundances of the so - called @xmath1-elements ( such as o , mg , or ca ) , which are produced via massive - star core - collapse supernovae of type ii ( snii ) , to abundances of iron , which is produced in sn ia .
probing elemental species that are created in other astrophysical sites , such as agb stars or wr stars , can add further constraints to bulge formation scenarios . |
9,621 | Suppose that you have an abstract for a scientific paper: we investigate the effects of the addition of pre - main sequence evolution to star cluster simulations .
we allowed stars to follow pre - main sequence tracks that begin at the deuterium burning birthline and end at the zero age main sequence .
we compared our simulations to ones in which the stars began their lives at the zero age main sequence , and also investigated the effects of particular choices for initial binary orbital parameters .
we find that the inclusion of the pre - main sequence phase results in a slightly higher core concentration , lower binary fraction , and fewer hard binary systems . in general
, the global properties of star clusters remain almost unchanged , but the properties of the binary star population in the cluster can be dramatically modified by the correct treatment of the pre - main sequence stage . .
And you have already written the first three sentences of the full article: over the past two decades , dynamical simulations of star clusters have become much more realistic .
this realism takes the form of an increasingly complex treatment of individual stars in the cluster . for years , dynamical models only considered stars as single equal - mass points .
the introduction of a mass function into dynamical models quickly necessitated some treatment of stellar evolution ..
Please generate the next two sentences of the article | high mass stars have much shorter lifetimes than low mass stars , mass loss from high mass stars can remove a significant fraction of the mass from the cluster , and very high mass stars can completely dominate the dynamical evolution of the cores of clusters @xcite .
binary stars also have a substantial impact on the cluster dynamics , by acting as energy sinks or sources . |
9,622 | Suppose that you have an abstract for a scientific paper: ground state of the quantum jahn - teller model with broken rotational symmetry was investigated by the variational approach in two cases : a lattice and a local ones .
both cases differ by the way of accounting for the nonlinearity hidden in the reflection - symmetric hamiltonian . in spite of
that the ground state energy in both cases shows the same features : there appear two regions of model parameters governing the ground state : the region of dominating selftrapping modified by the quantum effects and the region of dominating phonon - assisted tunneling ( antiselftrapping ) . in the local case ( i )
the effect of quantum fluctuations and anharmonicity due to the two - mode correlations is up to two orders larger than contributions due to the reflection effects of two - center wave function ; ( ii ) the variational results for the ground state energy were compared with exact numerical results . the coincidence is the better the more far away from the transition region at the e@xmath0e symmetry where the variational approach fails .
* ground state of quantum jahn - teller model : * * selftrapping vs correlated phonon - assisted * * tunneling * eva majernkov@xmath1 , and s. shpyrko@xmath2 @xmath3department of theoretical physics , palack university , t .
17 .
listopadu 50 , cz-77207 olomouc , czech republic @xmath4institute of physics , slovak academy of sciences , dbravsk cesta , sk-84 228 bratislava , slovak republic * list of content * 1 .
introduction 2 .
extended ( lattice ) generalized jahn - teller model 3 .
ground state of the lattice model 4 .
ground state of the local model 5 .
discussion of the numerical results 6 .
quantum fluctuations in the local model 7 . .
And you have already written the first three sentences of the full article: jahn - teller model as a protopype model for phonon removal of degeneracy of electron levels in complex molecules @xcite was investigated mainly in its rotational symmetric e@xmath0e local version with electron coupling to two degenerate intramolecular phonon modes , one antisymmetric and one symmetric against reflection.importance of focusing on the lattice version of the model increased due to jt - based structural phase transitions in some recently discovered high-@xmath5 superconductors and manganese - based perovskites @xcite , @xcite . for the reflection symmetric two - level electron - phonon models with linear coupling to one phonon mode ( exciton , dimer ) shore et al .
@xcite introduced variational wave function in a form of linear combination of the harmonic oscillator wave functions related with two levels .
two asymmetric minima of effective polaron potential turn coupled by a variational parameter respecting its anharmonism by assuming two - center variational phonon wave function ..
Please generate the next two sentences of the article | this approach was shown to yield the lowest ground state energy for the two - level models @xcite , @xcite .
the peculiarities due to reflection phenomena are also expected in the case of linear coupling with two phonon modes . |
9,623 | Suppose that you have an abstract for a scientific paper: the current status of the theory of particle acceleration at relativistic shocks is presented , and a few possible scenarios for ultra - high - energy cosmic ray production at such shocks are briefly discussed . .
And you have already written the first three sentences of the full article: relativistic shock waves are widely thought to generate energetic particles producing high - energy emission in many astrophysical sources .
the example of such sources can be hot spots in radio galaxies , jets in blazars and in galactic microquasars " , gamma - ray burst sources , and pulsar winds .
it is also believed that high - energy cosmic rays have their origin in astrophysical environments in which relativistic shocks occur ..
Please generate the next two sentences of the article | the aim of this paper is to present the current status of cosmic ray acceleration theory at relativistic shock waves and to briefly review and comment on the models proposed for ultra - high - energy cosmic ray production at such shocks .
the basic acceleration mechanism discussed in the context of cosmic ray production at shocks is the first - order fermi process . |
9,624 | Suppose that you have an abstract for a scientific paper: we present the essential findings of the screening theory of the integer quantum hall effect ( iqhe ) considering a quantum point contact ( qpc ) .
our approach is to solve the poisson and the schrdinger equations self - consistently , taking into account electron interactions , within a hartree type approximation for a two dimensional electron gas ( 2deg ) subject to high perpendicular magnetic fields .
the coulomb interaction between the electrons separates 2deg into two co - existing regions , namely quasi - metallic compressible and quasi - insulating incompressible regions , which exhibit peculiar screening and transport properties . in the presence of an external current ,
we show that this current is confined into the incompressible regions where the drift velocity is finite .
in particular , we investigate the distribution of these incompressible strips and their relation with the quantum hall plateaus considering a quasi 1d constriction , i.e. a qpc . .
And you have already written the first three sentences of the full article: the increasing amount of interest in quantum information processing attracted many experimentalists and theoreticians to investigate the transport properties of low dimensional charge systems . beyond interest to build quantum computational units , i.e. q - bits , and the calculation algorithms which are supposed to be used by these units , the coherency of the information processing , or in other words information transport , is an essential challenge . since some of the proposed units are defined on the 2deg , the information carriers are naturally the electrons . in the absence of an external magnetic field ,
the well - known and well - defined landauer channels @xcite are the best candidates for coherent transport .
these channels are by definition ballistic and 1d ..
Please generate the next two sentences of the article | they are formed due to the size quantization of the system under investigation .
a similar non - interacting single particle picture commonly used to describe the transport , also in the presence of an external magnetic field , is the so - called landauer - bttiker edge states ( lb - es ) @xcite . |
9,625 | Suppose that you have an abstract for a scientific paper: we study a non local version of the sine - gordon model connected to a many - body system with backward and umklapp scattering processes . using renormalization group methods
we derive the flow equations for the couplings and show how non locality affects the gap in the spectrum of charge - density excitations .
we compare our results with previous predictions obtained through the self - consistent harmonic approximation .
carlos m. nan@xmath0 and mariano j. salvay@xmath0 @xmath1 _ instituto de fsica la plata , departamento de fsica , facultad de ciencias exactas , universidad nacional de la plata .
cc 67 , 1900 la plata , argentina . _
@xmath2 _ consejo nacional de investigaciones cientficas y tcnicas , argentina . _ _ keywords : _ field theory , non local , renormalization group _ pacs : _
11.10.lm , 05.30.fk .
And you have already written the first three sentences of the full article: in general , quantum field theories have been built in the context of local models .
however , there exist physical situations that lead to non local interactions in a straightforward way .
let us mention , for instance , wheeler and feynman s description of charged particles @xcite , string theories with non local vertices @xcite , and non local kinetic terms that appear when bosonizing fermions in ( 2 + 1 ) dimensions @xcite @xcite ..
Please generate the next two sentences of the article | as we shall see , several recently considered non local field theories are related to the study of electronic systems in one spatial dimension ( 1d ) @xcite @xcite .
indeed , in recent years the physics of 1d systems of strongly correlated particles has become a very interesting subject since one can take advantage of the simplicity of the models at hand and , at the same time , expect to make contact with experiments . |
9,626 | Suppose that you have an abstract for a scientific paper: the first generation of stars ( commonly known as population iii ) are expected to form in low - mass protogalaxies in which molecular hydrogen is the dominant coolant .
radiation from these stars will rapidly build up an extragalactic ultraviolet background capable of photodissociating @xmath0 , and it is widely believed that this background will suppress further star formation in low - mass systems .
however , star formation will also produce an extragalactic x - ray background .
this x - ray background , by increasing the fractional ionization of protogalactic gas , promotes @xmath0 formation and reduces the effectiveness of ultraviolet feedback . in this paper , we examine which of these backgrounds has the dominant effect . using a simple model for the growth of the uv and x - ray backgrounds , together with a detailed one - dimensional model of protogalactic chemical evolution , we examine the effects of the x - ray backgrounds produced by a number of likely source models .
we show that in several cases , the resulting x - ray background is strong enough to offset uv photodissociation in large @xmath0-cooled protogalaxies . on the other hand , small protogalaxies ( those with virial temperatures @xmath1 ) remain dominated by the uv background in all of the models we examine .
we also briefly investigate the effects of the x - ray background upon the thermal and chemical evolution of the diffuse igm .
cosmology : theory galaxies : formation molecular processes radiative transfer .
And you have already written the first three sentences of the full article: in cosmological models based on cold dark matter ( cdm ) , the first stars are believed to form within small protogalaxies , with virial temperatures @xmath2 @xcite .
cooling within these protogalaxies is dominated by molecular hydrogen , @xmath0 , which forms via the gas - phase reactions @xmath3 and @xmath4 even in the absence of dust . although the fractional abundance of @xmath0 that forms in this way is small , it is sufficient to allow for effective cooling and the formation of stars @xcite .
as soon as massive stars form , however , they immediately begin to photoionize and photodissociate this @xmath0 ..
Please generate the next two sentences of the article | photoionization requires photons with energies greater than @xmath5 , which are strongly absorbed by neutral hydrogen , and is only of importance within regions .
photodissociation , by contrast , occurs through the absorption of photons in the lyman - werner band system @xcite , with energies in the range @xmath6 @xmath7 . |
9,627 | Suppose that you have an abstract for a scientific paper: elliptic flow of thermal photons has a great potential to explore the early time dynamics and evolution of quark gluon plasma . @xmath0
dependent temporal contours for photon spectra and elliptic flow from quark matter and hadronic phases , as well as the @xmath0 integrated results show gradual build - up of flow with time and relative contributions from different phases to that very clearly . unlike hadrons , photon flow is quite sensitive to the initial thermalization time @xmath1 , and its value can be estimated with the experimental determination of @xmath2 .
photons , elliptic flow , time evolution , @xmath1 etc . .
And you have already written the first three sentences of the full article: the observation of large anisotropic flow or in particular elliptic flow of different hadronic species at the relativistic heavy ion collider ( rhic ) at brookhaven national lab , new york , provides a strong confirmation of the formation of qgp .
photons are known to probe the properties of qgp in a relatively clean manner compared to hadrons . unlike hadrons , photons are emitted from every stage of the expanding system and also carry undistorted information from the production point to the detector .
elliptic flow is known to provide information about early thermalization and collectivity in the hot and dense matter ..
Please generate the next two sentences of the article | the flow parameter @xmath2 is quantified as the 2nd fourier co - efficient of the particle distribution in the transverse momentum plane as ( at mid - rapidity and for collisions of same type of nuclei only even cosine terms survive in the series below ) : @xmath3\end{aligned}\ ] ] we have shown that elliptic flow of thermal photons for @xmath4 gev au+au collisions at rhic ( using ideal hydrodynamic model ) reflects the anisotropies of the early partonic phase at large values of transverse momentum @xmath0 @xcite . in a recent calculation of photon @xmath2 ( considering prompt and jet photons along with thermal )
, it is shown that the thermal @xmath2 dominates over others for @xmath5 gev @xcite . for thermal photons along with contributions from qm and hm . |
9,628 | Suppose that you have an abstract for a scientific paper: photoluminescence measurements were carried out on be @xmath0-doped gaas / al@xmath1ga@xmath2as heterostructure at 1.6 k in magnetic fields ( @xmath3 ) up to 5 t. luminescence originating from recombination of a two - dimensional electron gas ( 2deg ) and photo excited holes localized on be acceptors was analyzed .
the degree of circular polarization ( @xmath4 ) of the luminescence from fully occupied landau levels was determined as a function of @xmath3 and the 2deg concentration , @xmath5 . at @xmath3 constant , @xmath4 decreased with the increase of @xmath5
. two mechanisms of the @xmath6 dependence are discussed : a ) the stark effect on a photo excited hole bound to be acceptor and b ) the in - plane anisotropy of the intensity of optical transitions .
a quantitative analysis shows that the influence of the stark effect on @xmath4 is negligible in the present experiment .
we propose that the @xmath6 dependence results from the @xmath7 symmetry of conduction band electron wavefunctions and we give qualitative arguments supporting this interpretation . .
And you have already written the first three sentences of the full article: let us consider a gaas / algaas heterostructure .
the point symmetry group of the constituent semiconductors is @xmath8 , but the presence of the interface reduces the symmetry of the heterostructure to @xmath7 . lowering the symmetry has important consequences on optical properties , leading to an anisotropy in the ( 001 ) plane .
this anisotropy is of the current interest and is studied both experimentally and theoretically ..
Please generate the next two sentences of the article | the landmark experiments were carried out by jusserand _
@xcite , kwok _ et al . _ |
9,629 | Suppose that you have an abstract for a scientific paper: sources of error fields were indirectly inferred in a stellarator by reconciling computed and numerical flux surfaces .
sources considered so far include the displacements and tilts of the four circular coils featured in the simple cnt stellarator .
the flux surfaces were measured by means of an electron beam and fluorescent rod , and were computed by means of a biot - savart field - line tracing code . if the ideal coil locations and orientations are used in the computation , agreement with measurements is poor .
discrepancies are ascribed to errors in the positioning and orientation of the in - vessel interlocked coils . to that end , an iterative numerical method was developed .
a newton - raphson algorithm searches for the coils displacements and tilts that minimize the discrepancy between the measured and computed flux surfaces .
this method was verified by misplacing and tilting the coils in a numerical model of cnt , calculating the flux surfaces that they generated , and testing the algorithm s ability to deduce the coils displacements and tilts .
subsequently , the numerical method was applied to the experimental data , arriving at a set of coil displacements whose resulting field errors exhibited significantly improved agreement with the experimental results . .
And you have already written the first three sentences of the full article: error fields ( efs ) have been and are the subject of intense study in tokamaks @xcite where relative errors as small as @xmath0 or even @xmath1 are known to affect stability , cause disruptions , and degrade confinement and plasma rotation .
error fields are obviously also very important in modern transport - optimized stellarators @xcite , whose performances rely on carefully optimized 3d magnetic fields .
the specially shaped coils that generate such fields are numerically optimized and , typically , are built and positioned with very high precision ..
Please generate the next two sentences of the article | in other words , errors are minimized at the construction stage .
vacuum fields are then experimentally characterized by a standard technique involving an electron beam and a fluorescent rod @xcite . |
9,630 | Suppose that you have an abstract for a scientific paper: we present an innovative technique which allows the simultaneous measurement of the dielectric constant of a material at many frequencies , spanning a four orders of magnitude range chosen between @xmath0 hz and @xmath1 hz .
the sensitivity and accuracy are comparable to those obtained using standard single frequency techniques .
the technique is based on three new and simple features : a ) the precise real time correction of the amplification of a current amplifier ; b ) the specific shape of the excitation signal and its frequency spectrum ; and c ) the precise synchronization between the generation of the excitation signal and the acquisition of the dielectric response signal .
this technique is useful in the case of relatively fast dynamical measurements when the knowledge of the time evolution of the dielectric constant is needed . .
And you have already written the first three sentences of the full article: dielectric spectroscopy has provided many informations to the investigation of complex materials , and especially to the field of glass transition phenomenon ( glass - forming systems ) during the last decades .
this technique gives direct access to the polarization of molecular dipoles allowing the study of relaxation processes .
it can probe the molecular structure and dynamics of several materials like liquids , polymer composites , colloids , porous materials , or ferroelectric crystals @xcite ..
Please generate the next two sentences of the article | it covers a wide range of frequency , typically from @xmath0 to @xmath2 hz , going up to @xmath3 hz with coaxial techniques @xcite .
dielectric liquids of small molecules like the glass - forming glycerol @xcite or glass - forming polymers @xcite have been extensively studied . |
9,631 | Suppose that you have an abstract for a scientific paper: observations of structure in circumstellar debris discs provide circumstantial evidence for the presence of massive planets at large ( several tens of au ) orbital radii , where the timescale for planet formation via core accretion is prohibitively long . here
, we investigate whether a population of distant planets can be produced via outward migration subsequent to formation in the inner disc .
two possibilities for significant outward migration are identified .
first , cores that form early at radii @xmath0 can be carried to larger radii via gravitational interaction with the gaseous disc .
this process is efficient if there is strong mass loss from the disc either within a cluster or due to photoevaporation from a star more massive than the sun but does not require the extremely destructive environment found , for example , in the core of the orion nebula .
we find that , depending upon the disc model , gas disc migration can yield massive planets ( several jupiter masses ) at radii of around 20 - 50 au .
second , interactions within multiple planet systems can drive the outer planet into a large , normally highly eccentric orbit .
a series of scattering experiments suggests that this process is most efficient for lower mass planets within systems of unequal mass ratio .
this mechanism is a good candidate for explaining the origin of relatively low mass giant planets in eccentric orbits at large radii .
accretion , accretion discs stars : formation stars : pre - main - sequence planetary systems : protoplanetary discs planets and satellites : formation .
And you have already written the first three sentences of the full article: with one exception ( konacki et al .
2003 ) , all confirmed extrasolar planets have been discovered by the doppler velocity technique . the selection effects inherent to radial velocity surveys ( cumming ,
marcy & butler 1999 ) favor the detection of planets at small orbital radii . to date , about half of the known planets have semi - major axis @xmath1 au , while the most distant - 55 cnc d - lies at @xmath2 au from its parent star .. indirect evidence , however , suggests that there could be a sizable population of massive planets at much greater radii ..
Please generate the next two sentences of the article | recent observations of dusty debris around vega have been interpreted as suggesting the presence of a planet of a few jupiter masses with @xmath3 ( wilner et al .
further , simulations modeling circumstellar dust discs suggest a planet lies at a distance of @xmath4 au from epsilon eridani ( ozernoy et al . |
9,632 | Suppose that you have an abstract for a scientific paper: recent studies have indicated that the emission of gravitational waves at the merger of two black holes gives a kick to the final black hole .
if the supermassive black hole at the center of a disk galaxy is kicked but the velocity is not large enough to escape from the host galaxy , it will fall back onto the the disk and accrete the interstellar medium in the disk .
we study the x - ray emission from the black holes with masses of @xmath0 recoiled from the galactic center with velocities of @xmath1 .
we find that their luminosities can reach @xmath2 , when they pass the apastrons in the disk . while the x - ray luminosities are comparable to those of ultra - luminous x - ray sources ( ulxs ) observed in disk galaxies , ulxs observed so far do not seem to be such supermassive black holes .
statical studies could constrain the probability of merger and recoil of supermassive black holes . .
And you have already written the first three sentences of the full article: recently , studies in numerical general relativity have shown that merged binary black holes can have a large recoil velocity through anisotropic emission of gravitational waves ( e.g. * ? ? ?
* ; * ? ? ?
the maximum velocity would reach @xmath3 , although the actual distribution of kick velocities is very uncertain ..
Please generate the next two sentences of the article | the discovery of such recoiled black holes is important for studies about the growth of black holes as well as the general relativity .
supermassive black holes ( @xmath4 ) at the centers of disk galaxies would be kicked through this mechanism . |
9,633 | Suppose that you have an abstract for a scientific paper: for a polytope we define the _ flag polynomial _ , a polynomial in commuting variables related to the well - known flag vector and describe how to express the the flag polynomial of the minkowski sum of @xmath0 standard simplices in a direct and canonical way in terms of the _ @xmath0-th master polytope _
@xmath1 where @xmath2 .
the flag polynomial facilitates many direct computations . to demonstrate this we provide two examples
; we first derive a formula for the @xmath3-polynomial and the maximum number of @xmath4-dimensional faces of the minkowski sum of two simplices .
we then compute the maximum discrepancy between the number of @xmath5-chains of faces of a minkowski sum of two simplices and the number of such chains of faces of a simple polytope of the same dimension and on the same number of vertices . *
2010 msc : * 05a15 , 05a16 , 52b05 , 52b11 .
* keywords : * polytope , minkowski sum , master polytope , flag polynomial , @xmath3-polynomial . .
And you have already written the first three sentences of the full article: for a polytope @xmath6 of dimension @xmath4 , the _ face vector _ of @xmath6 is given by @xmath7 where @xmath8 is the number of @xmath9-dimensional faces of @xmath6 .
it is an ongoing investigation to describe the face vectors for @xmath4-dimensional convex polytopes .
the case @xmath10 are the only cases where this description is complete . a nice theorem by steinitz @xcite states that an integer vector @xmath11 is a face vector for a three dimensional polytope @xmath6 if and only if ( i ) we have the euler relation @xmath12 , ( ii ) @xmath13 and ( iii ) @xmath14 ..
Please generate the next two sentences of the article | moreover , the first inequality is tight if and only if @xmath6 is simplicial , the second one is tight if and only if @xmath6 is simple .
the only linear equation satisfied by the entries of the face vector is the euler - poincar relation @xmath15 , that holds for all polytopes of dimension @xmath4 . for higher dimensions |
9,634 | Suppose that you have an abstract for a scientific paper: it is meaningful to detect outliers in traffic data for traffic management .
however , this is a massive task for people from large - scale database to distinguish outliers . in this paper
, we present two methods : kernel smoothing nave bayes ( nb ) method and gaussian mixture model ( gmm ) method to automatically detect any hardware errors as well as abnormal traffic events in traffic data collected at a four - arm junction in hong kong .
traffic data was recorded in a video format , and converted to spatial - temporal ( st ) traffic signals by statistics .
the st signals are then projected to a two - dimensional ( 2d ) ( x , y)-coordinate plane by principal component analysis ( pca ) for dimension reduction .
we assume that inlier data are normal distributed .
as such , the nb and gmm methods are successfully applied in od ( outlier detection ) for traffic data .
the kernel smooth nb method assumes the existence of kernel distributions in traffic data and uses bayes theorem to perform od .
in contrast , the gmm method believes the traffic data is formed by the mixture of gaussian distributions and exploits confidence region for od .
this paper would address the modeling of each method and evaluate their respective performances .
experimental results show that the nb algorithm with triangle kernel and gmm method achieve up to * 93.78% * and * 94.50% *
accuracies , respectively . .
And you have already written the first three sentences of the full article: it is desired that most events to be safe , stable or rather predictable . identifying an unusual event
is a typical and vital topic in different fields , such as intrusion detection in cyber security , fraud detection for credit cards , insurance or health care and fault detection in safety critical systems @xcite .
we may call this unusual event as outlier or abnormality which is different from a usual event ..
Please generate the next two sentences of the article | outlier is usually minor in a group of events / data while inlier is the majority .
od refers to detect any abnormal element in data which is not consistent with an expected behavior @xcite . |
9,635 | Suppose that you have an abstract for a scientific paper: we have identified 469 doublet systems having @xmath0 in 252 keck / hires and uves / vlt quasar spectra over the redshift range @xmath1 . using the largest sample yet of 188 weak systems ( @xmath2 @xmath3 ) , we calculate their absorber redshift path density , @xmath4 .
we find clear evidence of evolution , with @xmath4 peaking at @xmath5 , and that the product of the absorber number density and cross section decreases linearly with increasing redshift ; weak absorbers seem to vanish above @xmath6 .
if the absorbers are ionized by the uv background , we estimate number densities of @xmath7 per mpc@xmath8 for spherical geometries and @xmath9 per mpc@xmath8 for more sheetlike geometries .
we also find that @xmath4 toward intrinsically faint versus bright quasars differs significantly for weak and strong ( @xmath10 ) absorbers .
for weak absorption , @xmath4 toward bright quasars is @xmath11 higher than toward faint quasars ( 10 @xmath12 at low redshift , @xmath13 , and 4 @xmath12 at high redshift , @xmath14 ) . for strong absorption
the trend reverses , with @xmath4 toward faint quasars being @xmath15 higher than toward bright quasars ( also 10 @xmath12 at low redshift and 4 @xmath12 at high redshift ) .
we explore scenarios in which beam size is proportional to quasar luminosity and varies with absorber and quasar redshifts .
these do not explain @xmath4 s dependence on quasar luminosity . .
And you have already written the first three sentences of the full article: quasar absorption line systems are an extremely useful means of statistically constraining the various scenarios of metal enrichment , inflow and outflow , ionization conditions , kinematics , and gas structure within galaxies and the igm .
various absorption line studies have concluded that these systems are cosmologically distributed @xcite , and numerous subsequent studies have identified specific galaxies associated with absorption ( see * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
9,636 | Suppose that you have an abstract for a scientific paper: physical systems with a large scattering length have universal properties independent of the details of the interaction at short distances . such systems can be realized in experiments with cold atoms close to a feshbach resonance .
they also occur in many other areas of physics such as nuclear and particle physics .
the universal properties include a geometric spectrum of three - body bound states ( so - called efimov states ) and log - periodic dependence of low - energy observables on the physical parameters of the system .
this behavior is characteristic of a renormalization group limit cycle .
we discuss universality in the three- and four - body sectors and give an overview of applications in cold atoms . .
And you have already written the first three sentences of the full article: the effective field theory ( eft ) approach provides a powerful framework that exploits the separation of scales in physical systems .
only low - energy ( or long - range ) degrees of freedom are included explicitly , with the rest parametrized in terms of the most general local ( contact ) interactions .
this procedure exploits the fact that a low - energy probe of momentum @xmath0 can not resolve structures on scales smaller than @xmath1 . in this talk . ] using renormalization , the influence of short - distance physics on low - energy observables is captured in a small number of low - energy constants ..
Please generate the next two sentences of the article | thus , the eft describes universal low - energy physics independent of detailed assumptions about the short - distance dynamics .
all physical observables can be described in a controlled expansion in powers of @xmath2 , where @xmath3 is the characteristic low - energy length scale of the system . |
9,637 | Suppose that you have an abstract for a scientific paper: the potentials @xmath0 in the nonrelativistic ( relativistic ) nucleon - nucleon ( nn ) schrdinger equation are related by a quadratic equation .
that equation is numerically solved , thus providing phase equivalent @xmath1 - potentials related for instance to the high precision nn potentials , which are adjusted to nn phase shift and mixing parameters in a nonrelativistic schrdinger equation .
the relativistic nn potentials embedded in a three - nucleon ( 3n ) system for total nn momenta different from zero are also constructed in a numerically precise manner .
they enter into the relativistic interacting 3n mass operator , which is needed for relativistic 3n calculations for bound and scattering states . .
And you have already written the first three sentences of the full article: traditionally the ( semi ) phenomenological high precision two - nucleon ( nn)potentials av18 @xcite , cd bonn @xcite and nijm i , ii @xcite go together with the nonrelativistic operator for the kinetic energy @xmath2 in the nn c.m.system .
nevertheless , as is well known , this nonrelativistic schrdinger equation @xmath3 can be related to an underlying relativistic nn schrdinger equation @xmath4 by a simple algebraic step@xcite,@xcite .
applying @xmath5 to ( [ 2 ] ) from the left one obtains @xmath6 which can be identically rewritten into ( [ 1 ] ) if one defines @xmath7 with @xmath8 ..
Please generate the next two sentences of the article | ( we use @xmath9 in order to distinguish the momentum operator from the number @xmath10 ) . therefore adjusting @xmath11 in ( [ 1 ] ) to the nn phase shift and mixing parameters from a phase shift analysis and relating the c.m .
momentum @xmath12 to the lorentz invariant lab energy @xmath13 via @xmath14 ( a relation identically valid for relativistic and nonrelativistic kinematics ) one has in fact solved a relativistic equation . |
9,638 | Suppose that you have an abstract for a scientific paper: we present observations from the small array of the arcminute microkelvin imager ( ami ) of eight high x - ray luminosity galaxy cluster systems selected from the local cluster substructure survey ( locuss ) sample .
we detect the sunyaev - zeldovich ( sz ) effect in seven of these clusters . with the assumptions that galaxy clusters are isothermal , have a density profile described by a spherical @xmath0-model and obey the theoretical m - t relation , we are able to derive cluster parameters at @xmath1 from our sz data . with the additional assumption of hydrostatic equilibrium we are able to derive parameters at @xmath2 .
we present posterior probability distributions for cluster parameters such as mass , radius and temperature ( @xmath3 ) .
combining our sample with that of ami consortium : rodrguez - gonzlvez et al .
( 2011 ) and using large - radius x - ray temperature estimates ( @xmath4 ) from _ chandra _ and _ suzaku _ observations , we find that there is reasonable correspondence between @xmath4 and @xmath3 values at low @xmath4 , but that for clusters with @xmath4 above around 6kev the correspondence breaks down with @xmath4 exceeding @xmath3 ; we stress that this finding is based on just ten clusters .
cosmology : observations - sunyaev - zeldovich galaxies : clusters x - ray cosmic microwave background galaxies : clusters : individual ( abell 586 , abell 611 , abell 773 , abell 781 , abell 1413 , abell 1758 , zw1454.8 + 2233 and rxj1720 + 2638 ) .
And you have already written the first three sentences of the full article: the local cluster substructure survey ( locuss see smith et al . 2003 , 2005 ) sample of clusters contains 164 clusters with redshifts between 0.142 and 0.295 .
the locuss aims to measure the relationship between the structure of galaxy clusters and the evolution of the hot gas and galaxies that inhabit them using gravitational lensing data and other observations spanning the electromagnetic spectrum from the radio to x - ray .
example locuss analysis papers relevant to this work are @xcite and @xcite ..
Please generate the next two sentences of the article | we have imaged a subset of locuss in the sunyaev - zeldovich ( sz ; @xcite ) effect with the arcminute microkelvin imager ( ami ; see e.g. @xcite ) centred at 16 ghz .
the sz signal arises from the inverse compton scattering of cosmic microwave background ( cmb ) photons by the hot cluster plasma ( see e.g. @xcite and @xcite ) , with a surface brightness that is independent of redshift and dependencies on plasma density and temperature that are different to those for e.g. x - ray bremsstrahlung emission . |
9,639 | Suppose that you have an abstract for a scientific paper: the offline processing of the data collected by the belle detector has been recently upgraded to cope with the excellent performance of the kekb accelerator .
the 127 fb@xmath0 of data ( 120 tb on tape ) collected between autumn 2003 and summer 2004 has been processed in 2 months , thanks to the high speed and stability of the new , distributed processing scheme .
we present here this new processing scheme and its performance . .
And you have already written the first three sentences of the full article: the belle experiment @xcite , located on the kekb @xcite asymmetric - energy @xmath1 collider , is primarily devoted to the study of cp violation in the @xmath2 meson system .
kekb has shown a very stable operation with increasing luminosity over the years .
it has turned to so - called `` continuous injection mode '' last january , thus allowing a gain in the integrated luminosity of about 30% . in this mode , the beam particle losses are compensated by continuously injecting beam from the linear accelerator , without interruption of data taking . kekb has reached a world record peak luminosity of @xmath3 @xmath4s@xmath0 and an integrated luminosity of about 1 fb@xmath0 per day . in the meanwhile ,.
Please generate the next two sentences of the article | belle has accumulated a total integrated luminosity of 290 fb@xmath0 ( about 275 million @xmath2 meson pairs ) , among which 127 fb@xmath0 was collected between october 2003 and july 2004 ( svd2 run ) .
.belle data acquisition and processing figures . |
9,640 | Suppose that you have an abstract for a scientific paper: full counting statistics of electron transport is a powerful diagnostic tool for probing the nature of quantum transport beyond what is obtainable from the average current or conductance measurement alone . in particular , the non - markovian dynamics of quantum dot molecule plays an important role in the nonequilibrium electron tunneling processes .
it is thus necessary to understand the non - markovian full counting statistics in a quantum dot molecule .
here we study the non - markovian full counting statistics in two typical quantum dot molecules , namely , serially coupled and side - coupled double quantum dots with high quantum coherence in a certain parameter regime .
we demonstrate that the non - markovian effect manifests itself through the quantum coherence of the quantum dot molecule system , and has a significant impact on the full counting statistics in the high quantum - coherent quantum dot molecule system , which depends on the coupling of the quantum dot molecule system with the source and drain electrodes .
the results indicated that the influence of the non - markovian effect on the full counting statistics of electron transport , which should be considered in a high quantum - coherent quantum dot molecule system , can provide a better understanding of electron transport through quantum dot molecules . .
And you have already written the first three sentences of the full article: full counting statistics@xcite ( fcs ) of electron transport through mesoscopic system has attracted considerable attention both experimentally and theoretically because it can provide a deeper insight into the nature of electron transport mechanisms , which can not be obtained from the average current blanter , nazarov , gustavsson , fujisawa , flindt , fricke01,ubbelohde , fricke02,maisi .
for instance , the shot noise measurements can be used to probe the dynamical in an open double quantum dots ( qds ) @xcite , the coherent coupling between serially coupled qds @xcite , the evolution of the kondo effect in a qd @xcite , and the conduction channels of quantum conductors @xcite . in particular , shot noise characteristics can provide information about the feature of the pseudospin kondo effect in a laterally coupled double qds @xcite , the spin accumulations in a electron reservoir @xcite , and the charge fractionalization in the @xmath0 quantum hall edge milletari .
in addition , the degree of entanglement of two electrons in the double qds @xcite , the dephasing rate in a closed qd @xcite , the internal level structure of single molecule magnet xuejap10,xuepla11 can be characterized by the super - poissonian shot noise . on the other hand ,.
Please generate the next two sentences of the article | the quantum coherence in coupled qd system , which is characterized by the off - diagonal elements of the reduced density matrix of the qd system within the framework of the density matrix theory@xcite , plays an important role in the electron tunneling processes and has a significant influence on electron transport gurvitz , braun , wunsch , djuric01,djuric02,harbola , pedersen , begemann , darau , schultz , schaller .
in particular , theoretical studies have demonstrated that the high - order cumulants , e.g. , the shot noise , the skewness , are more sensitive to the quantum coherence than the average current in the different types of qd systems @xcite and the quantum coherence information in a side - coupled double qd system can be extracted from the high - order current cumulants @xcite . |
9,641 | Suppose that you have an abstract for a scientific paper: we describe a procedure for mapping a self - consistent mean - field theory ( also known as density functional theory ) into a shell model hamiltonian that includes quadrupole - quadrupole and monopole pairing interactions in a truncated space .
we test our method in the deformed @xmath0 @xmath1-shell nuclei @xmath2ne , @xmath3 mg and @xmath4ar , starting from the hartree - fock plus bcs approximation of the usd shell model interaction . a similar procedure
is then followed using the sly4 skyrme energy density functional in the particle - hole channel plus a zero - range density - dependent force in the pairing channel . using the ground - state solution of this density functional theory at the hartree - fock plus bcs level
, an effective shell model hamiltonian is constructed .
we use this mapped hamiltonian to extract quadrupolar and pairing correlation energies beyond the mean field approximation .
the rescaling of the mass quadrupole operator in the truncated shell model space is found to be almost independent of the coupling strength used in the pairing channel of the underlying mean - field theory . .
And you have already written the first three sentences of the full article: one of the major challenges in nuclear many - body theory is to develop a microscopic and systematic approach that would account for the most relevant correlations in the description of nuclear properties .
most existing methods can be divided into two major classes : the self - consistent mean field ( scmf ) approximation @xcite , also known as density functional theory ( dft ) , and the configuration - interaction shell model ( cism ) approach @xcite .
scmf theories are often cast in terms of an energy density functional that is minimized to obtain the ground - state solution of the system . there.
Please generate the next two sentences of the article | exist parameterizations of this energy density functional that are valid globally through the table of nuclei .
such parametrizations are usually based on the zero - range skyrme force @xcite or on the gogny interaction @xcite . |
9,642 | Suppose that you have an abstract for a scientific paper: integro - differential methods , currently exploited in calculus , provide an inexhaustible source of tools to be applied to a wide class of problems , involving the theory of special functions and other subjects .
the use of integral transforms of the borel type and the associated formalism is shown to be a very effective mean , constituting a solid bridge between umbral and operational methods .
we merge these different points of view to obtain new and efficient analytical techniques for the derivation of integrals of special functions and the summation of associated generating functions as well . .
And you have already written the first three sentences of the full article: operational methods , developed within the context of the fractional derivative formalism @xcite , have opened new possibilities in the application of calculus .
even classical problems , with well - known solutions , may acquire a different flavor if viewed from such a perspective .
this , if properly pursued , may allow for further progress , disclosing new avenues of study and generalizations . as it is well known , the operation of integration is the inverse of that of derivation ..
Please generate the next two sentences of the article | such a statement by itself does not enable any means to establish `` practical '' rules to handle integrals and derivatives on the same footing .
an almost natural environment for this specific assertion are the technicalities associated with the formalism of _ real order _ derivatives ( i.e. not necessarily positive ) , in which the distinction between integrals and derivatives becomes superfluous . |
9,643 | Suppose that you have an abstract for a scientific paper: most current astronomical adaptive optics ( ao ) systems rely on the availability of a bright star to measure the distortion of the incoming wavefront .
replacing the guide star with an artificial laser beacon alleviates this dependency on bright stars and therefore increases sky coverage , but it does not eliminate another serious problem for ao observations . this is the issue of psf variation with time and field position near the guide star .
in fact , because a natural guide star is still necessary for correction of the low - order phase error , characterization of laser guide star ( lgs ) ao psf spatial variation is more complicated than for a natural guide star alone .
we discuss six methods for characterizing lgs ao psf variation that can potentially improve the determination of the psf away from the laser spot , that is , off - axis .
calibration images of dense star fields are used to determine the change in psf variation with field position .
this is augmented by ao system telemetry and simple computer simulations to determine a more accurate off - axis psf .
we report on tests of the methods using the laser ao system on the lick observatory shane telescope .
we observed with offsets typical of separations between dim science targets and the nearest suitably bright tip - tilt guide star , up to 20 .
if the tip - tilt guide star is used as the psf reference , the predicted strehl ratio within an 8 radius of the lgs can be more than a factor of two too high , due to not taking into account the field dependent anisoplanatism .
a better result may be obtained by an improved empirical approach : repositioning the tip - tilt guide star to compensate for the additional 8 offset .
this would result in a 27% relative error in strehl ratio .
a simple gaussian model of psf variation can reduce the error in the prediction to @xmath020% .
some further improvement may by obtained semianalytically , by using telemetry from the ao system ( 14% error ) plus a more sophisticated theoretical....
And you have already written the first three sentences of the full article: an introduction to the problem of characterizing the psf of a natural guide star ( ngs ) adaptive optics ( ao ) system is given in @xcite ( hereafter referred to as paper i ) .
in an ngs observation a bright star is used to guide the ao system while the telescope is pointed at a scientific target which is typically 10 - 30 away , and perhaps as distant as 1 . because the performance of the ao system degrades for fainter guide stars - correction is poorer as signal - to - noise ( s / n ) on the wavefront sensor ( wfs ) decreases - any subsequent calibration observation must use a guide star of similar brightness .
even so , the delivered correction depends directly on quickly changing seeing conditions ( measured by the fried parameter @xmath1 ) and is therefore not likely to be the same during the two observations . further aggravating this.
Please generate the next two sentences of the article | , the spatial dependence of the phase error is dependent on the distribution of turbulence strength along the line of sight ( given by the @xmath2 profile , where @xmath3 is height ) , and thus psf anisoplanatism can be strong and change with time . therefore a calibration measurement done with the same offset but at a later time may provide little information about the psf at the scientific target . in paper
i we discussed a method which may improve the determination of the ao off - axis psf . |
9,644 | Suppose that you have an abstract for a scientific paper: two searches for new phenomena involving top quarks are presented : a search for a top partner in events with large missing transverse momentum , and a search for resonances in proton - proton collisions at a center - of - mass energy of 7 tev .
the measurements are based on 35 and 200 of data collected with the atlas detector at the lhc in 2010 and 2011 , respectively .
no evidence for a signal is observed .
the first limits from the lhc are established on the mass of a top partner , excluding a mass of 275 gev for a neutral particle mass less than 50 gev and a mass of 300 gev for a neutral particle mass less than 10 gev . using the reconstructed mass spectrum ,
limits are set on the production cross - section times branching ratio to for narrow and wide resonances . for narrow models , the observed 95% c.l .
limits range from approximately 38 pb to 3.2 pb for masses going from @xmath0 500 gev to @xmath0 1300 gev . in randall - sundrum models , kaluza - klein gluons with masses below 650 gev
are excluded at 95% c.l . .
And you have already written the first three sentences of the full article: the standard model of particle physics is believed to be an effective theory valid up to energies close to 1 tev .
however , no new physics beyond the standard model ( sm ) has been observed yet , and it is critical to explore a wide range of possible signatures .
a promising avenue lies in final states that involve the heaviest of the particles presumed to be elementary : the top quark ..
Please generate the next two sentences of the article | this document describes two searches for new phenomena involving top quarks using the atlas detector @xcite at the cern large hadron collider ( lhc ) .
the first search is carried out for a pair - produced exotic top partner ( @xmath1 ) , decaying to a top - antitop pair and two stable , neutral weakly - interacting particles ( @xmath2 , which in some models may be its own anti - particle ) @xcite . in most models , the @xmath1 has typical quark - like quantum numbers , and is produced through @xmath3 annihilation and gluon fusion . |
9,645 | Suppose that you have an abstract for a scientific paper: the high - redshift radio - loud quasar pks 2126@xmath0158 is found to have a large number of red galaxies in close apparent proximity .
we use the gemini multi - object spectrograph ( gmos ) on gemini south to obtain optical spectra for a large fraction of these sources .
we show that there is a group of galaxies at @xmath1 , coincident with a metal - line absorption system seen in the quasar s optical spectrum .
the multiplexing capabilities of gmos also allow us to measure redshifts of many foreground galaxies in the field surrounding the quasar .
the galaxy group has five confirmed members , and a further four fainter galaxies are possibly associated .
all confirmed members exhibit early - type galaxy spectra , a rare situation for a absorbing system .
we discuss the relationship of this group to the absorbing gas , and the possibility of gravitational lensing of the quasar due to the intervening galaxies .
[ firstpage ] quasars : individual : pks 2126@xmath0158 quasars : absorption lines galaxies : general gravitational lensing .
And you have already written the first three sentences of the full article: quasars located at high redshifts provide excellent probes of the intervening universe .
as their light travels through the universe , it is partially absorbed by neutral hydrogen or metals such as magnesium an effect detectable in the quasars optical and uv spectra .
these absorption lines provide an effective way of probing the evolution of metal - bearing gas over a large range of redshifts , as the sensitivity to absorption is largely independent of redshift , depending only on the background source s surface brightness ..
Please generate the next two sentences of the article | the absorption systems in particular are most likely associated with foreground galaxies @xcite , based on the velocity structure within the systems , the clustering properties of the absorbers , and the presence of metals that have most likely been produced locally .
when identified , most of these galaxies appear to be spirals ( e.g. * ? ? ? |
9,646 | Suppose that you have an abstract for a scientific paper: we present a theoretical study on polaritons in highly doped semiconductor microcavities . in particular , we focus on a cavity mode that is resonant with the absorption threshold ( ` fermi edge ' ) . in agreement with experimental results ,
the strong light - matter coupling is maintained under very high doping within our ladder diagram approximation .
while the lower polariton is qualitatively unaltered , it acquires a finite lifetime due to relaxation of the valence band hole if the electron density exceeds a certain critical value . on the other hand
the upper polariton has a finite lifetime for all densities , because it lies in the electron - hole continuum where no bound state exists .
our calculations show that a narrow upper polariton quasiparticle still exists as a result from the interplay between light - matter coupling and final state coulomb interaction .
microcavity polaritons are bosonic quasiparticles that appear in a semiconductor microcavity with an embedded quantum well ( qw ) when the cavity is tuned to an excitonic transition in the qw . in the last decade they have emerged as quasiparticles with many favorable properties for studying quantum optics and many - body physics in integrated photonic structures .
bose - einstein condensation of polaritons and their superfluid properties have been investigated in detail both experimentally and theoretically @xcite . in these studies ,
the tunability of the polariton properties is often exploited .
for example , the number of quantum wells is varied to change the rabi frequency ; etching , strain and surface acoustic waves have been used to create potentials for the polaritons .
a tuning parameter that has received relatively little attention is the introduction of charges in the qw that interact with the polaritons . in the case of low charge concentration ,
trionic bound states exist and a trionic polariton is observed @xcite .
an experiment with high density modulation doping was performed by gabbay _
et al .
....
And you have already written the first three sentences of the full article: in this section we derive the expression for the matter hamiltonian ( 6 ) used in the article . with the assumption of a frequency - independent final state coulomb interaction , from the ladder diagrams in fig .
2 , a bethe - salpeter equation for the electron - hole bubble @xmath40 can be found along the lines of ref .
this integral equation for the vertex factor @xmath40 is given by @xmath41 the solution of this equation yields the photon polarization by the following relation @xmath42 where for simplicity we have set the photon momentum equal to zero ..
Please generate the next two sentences of the article | the function @xmath43 is given by the matsubara summation over the internal fermionic frequency @xmath44 of the electron and hole propagators , defined in fig .
2 . because we consider a zero photon momentum , only electrons and holes with opposite momentum contribute . |
9,647 | Suppose that you have an abstract for a scientific paper: we study a stable , soliton - like solution in the linear @xmath0-model where the chiral fields are coupled to a single massless nonstrange quark .
we investigate a possibility that this solution represents the constituent quark of georgi and manohar .
we show that its properties are indeed consistent with nucleon observables .
furthermore , we derive chiral meson exchange potentials between such objects which are similar to recently used potentials in the constituent quark models . and _
pacs : _
12.39.fe , 14.65.bt .
And you have already written the first three sentences of the full article: the successes of the nonrelativistic constituent quark models stimulate the study of the microscopic structure of the constituent quark .
such a structure can not only influence predictions for many observables of the nucleon but also offer a possibility to derive an important part of the effective interaction between constituent quarks .
the idea that the constituent quark is represented by a current quark surrounded by a chiral field , stems from georgi and manohar @xcite and has been further elaborated by cheng and li @xcite , and by baumgartner , pirner , knigsmann and povh @xcite in order to account for the parton counting in deep inelastic scattering ( related to the flavour asymmetry of sea quarks as given by the gottfried sum ; and to strangeness and spin content of the nucleon ) ..
Please generate the next two sentences of the article | we offer an explicit candidate for such a constituent quark : a soliton - like solution of a coherent state of pions and @xmath0-mesons around a massless quark in the linear @xmath0-model .
the choice of a mesonic rather than gluonic description of the structure of the constituent quark is based on the experience that the scale for chiral symmetry breaking and emergence of chiral goldstone bosons appears at lower energies than the confinement scale where gluons dominate . |
9,648 | Suppose that you have an abstract for a scientific paper: we present near - infrared spectroscopy for a complete sample of 33 ultraluminous infrared galaxies at a resolution of @xmath0 .
most of the wavelength range from 1.802.20 @xmath1 m in the rest frame is covered , including the pa@xmath2 and br@xmath3 hydrogen recombination lines , and the molecular hydrogen vibration - rotation 10 s(1 ) and s(3 ) lines .
other species , such as he i , [ fe ii ] , and [ si vi ] appear in the spectra as well , in addition to a number of weaker molecular hydrogen lines .
nuclear extractions for each of the individual galaxies are presented here , along with spectra of secondary nuclei , where available .
the pa@xmath2 emission is seen to be highly concentrated on the nuclei , typically with very little emision extending beyond a radius of 1 kpc .
this survey was carried out primarily to search for signatures of active nuclei via velocity - broadened hydrogen recombination or the presence of the [ si vi ] coronal line .
these signatures are rare in the present sample , occurring in only two of the 33 galaxies .
the extinction to the hydrogen recombination lines is investigated via the pa@xmath4br@xmath3 line ratio .
it is found that visual extinctions to the nuclei in excess of 10 magnitudes are relatively common among ulirgs , and that visual extinctions greater than 25 mag are necessary to conceal a qso emitting half the total bolometric luminosity .
the ionized hydrogen regions in many ulirgs are sufficiently obscured that dust - enshrouded active galactic nuclei would remain hidden at 2 @xmath1 m at the current level of sensitivity
. the vibration - rotation lines of molecular hydrogen appear to be predominantly thermal in origin , with effective temperatures generally around 2200 k. the relative nuclear velocities between double nucleus ulirgs are investigated , through which it is inferred that the maximum deprojected velocity difference is @xmath5 km s@xmath6 . this figure is lower than the velocities predicted by physical models of strong....
And you have already written the first three sentences of the full article: understanding the nature of the ultimate power source in ultraluminous infrared galaxies ( ulirgs ) has been a primary driver for numerous scientific investigations ever since the discovery in the 1980 s that ulirgs represent the most luminous class of galaxies in the local universe . with total power outputs comparable to those of quasars , characterizing the source of power
is of fundamental importance in understanding the composition and evolution of normal galaxies .
ulirgs are found to share the common trait that virtually all have recently or are currently experiencing major encounters with other galaxies @xcite . encounters like these may play a significant role in the process of building normal galaxies . with the discovery of faint sources at sub - millimeter wavelengths having characteristic spectral energy distributions like that typically found in ulirgs ( e.g. , arp 220 ) and redshifts @xmath7 , the importance of understanding these systems and their role in the evolution of normal galaxies has been heightened ..
Please generate the next two sentences of the article | the present survey was designed to look for near - infrared spectral signatures of obscured active galactic nuclei ( agn ) in ulirgs , either by the presence of velocity - broadened pa@xmath2 emission or by the appearance of the high excitation [ coronal line .
a summary of the conclusions of this survey , along with a median ulirg near - infrared spectrum , are presented in @xcite . |
9,649 | Suppose that you have an abstract for a scientific paper: segmenting images of low quality or with missing data is a challenging problem .
integrating statistical prior information about the shapes to be segmented can improve the segmentation results significantly .
most shape - based segmentation algorithms optimize an energy functional and find a point estimate for the object to be segmented .
this does not provide a measure of the degree of confidence in that result , neither does it provide a picture of other probable solutions based on the data and the priors . with a statistical view , addressing these issues would involve the problem of characterizing the posterior densities of the shapes of the objects to be segmented . for such characterization , we propose a markov chain monte carlo ( mcmc ) sampling - based image segmentation algorithm that uses statistical shape priors .
in addition to better characterization of the statistical structure of the problem , such an approach would also have the potential to address issues with getting stuck at local optima , suffered by existing shape - based segmentation methods .
our approach is able to characterize the posterior probability density in the space of shapes through its samples , and to return multiple solutions , potentially from different modes of a multimodal probability density , which would be encountered , e.g. , in segmenting objects from multiple shape classes .
we present promising results on a variety of data sets .
we also provide an extension for segmenting shapes of objects with parts that can go through independent shape variations .
this extension involves the use of local shape priors on object parts and provides robustness to limitations in shape training data size . .
And you have already written the first three sentences of the full article: prior knowledge about the shapes to be segmented is required for segmentation of images involving limited and low quality data . in many applications ,
object shapes come from multiple classes ( i.e. , the prior shape density is multimodal " ) and the algorithm does not know the class of the object in the scene .
for example , in the problem of segmenting objects in a natural scene ( e.g. , cars , planes , trees , etc . ).
Please generate the next two sentences of the article | , a segmentation algorithm should contain a training set of objects from different classes .
another example of a multimodal density is the shape density of multiple handwritten digits , e.g. , in an optical character segmentation and recognition problem . in this paper , we consider segmentation problems that involve limited and challenging image data together with complex and potentially multimodal shape prior densities . [ cols= " < , < , < , < , < " , ] + & & & & & & + & & & & & & + & & & & & & |
9,650 | Suppose that you have an abstract for a scientific paper: in this brief comment , we consider the exact , deterministic , and nonasymptotic transformation of multiple copies of pure states under locc .
it was conjectured in quant - ph/0103131 that , if @xmath0 copies of @xmath1 can be transformed to @xmath0 copies of @xmath2 , the same holds for all @xmath3 .
we present counterexamples to the above conjecture . .
And you have already written the first three sentences of the full article: we consider pure bipartite states shared by alice and bob .
let @xmath4 and @xmath5 be the labels of their respective quantum systems , each with @xmath6 dimensions .
suppose alice and bob want to transform a state @xmath1 to another state @xmath2 ..
Please generate the next two sentences of the article | they each have complete classical descriptions of the states , but they can only perform local quantum operations and classical communication ( locc ) @xcite . the transformation can be performed under many scenarios
. the final state can be exactly or approximately the desired output , and the transformation can work deterministically or with certain probability . |
9,651 | Suppose that you have an abstract for a scientific paper: we report new detections of the hotspots in cygnus a at 4.5 and 8.0 microns with the _ spitzer space telescope_. together with detailed published radio observations and synchrotron self - compton modeling of previous x - ray detections , we reconstruct the underlying electron energy spectra of the two brightest hotspots ( a and d ) .
the low - energy portion of the electron distributions have flat power - law slopes ( @xmath0 ) up to the break energy which corresponds almost exactly to the mass ratio between protons and electrons ; we argue that these features are most likely intrinsic rather than due to absorption effects . beyond the break ,
the electron spectra continue to higher energies with very steep slopes @xmath13 .
thus , there is no evidence for the ` canonical ' s=2 slope expected in 1st order fermi - type shocks within the whole observable electron energy range .
we discuss the significance of these observations and the insight offered into high - energy particle acceleration processes in mildly relativistic shocks . .
And you have already written the first three sentences of the full article: cygnus a is the nearest example ( @xmath2=0.056 ) of a powerful fanaroff - riley type - ii radio galaxy . as such
, it contains some of the brightest radio hotspots to study these classical ` working surfaces ' of relativistic jets ( hargrave & ryle 1974 ; blandford & rees 1974 ) . although the hotspots are well - studied at radio and x - ray wavelengths ( 2 ) , cygnus a is viewed through the galactic plane , making them difficult to study at optical wavelengths ( 1.26 mag of extinction at v - band ; meisenheimer et al .
additionally , it is well known that bright foreground stars lie in the direction of cygnus a , and this has also hindered optical studies of the hotspots . to circumvent these obstacles.
Please generate the next two sentences of the article | , we obtained new _
spitzer space telescope _ images ( figure 1 ) resulting in successful mid - infrared detections of the hotspots . |
9,652 | Suppose that you have an abstract for a scientific paper: we investigate the tuning behavior of a novel type of single - frequency optical synthesizers by phase comparison of the output signals of two identical devices .
we achieve phase - stable and cycle slip free frequency tuning over 28.1 ghz with a maximum zero - to - peak phase deviation of 62 mrad .
in contrast to previous implementations of single - frequency optical synthesizers , no comb line order switching is needed when tuned over more than one comb line spacing range of the employed frequency comb .
a single - frequency optical synthesizer ( sos ) is the analog of an electrical synthesizer in the optical domain .
it provides a single - frequency optical field whose frequency and phase can be arbitrarily adjusted within a certain spectral range and resolution while it is related to a reference signal in a phase - coherent fashion . in an ideal case
it combines the best of two worlds in a tunable way , i.e. the spectral resolution of narrow linewidth frequency stabilized lasers with the broad spectral coverage of frequency combs .
+ such an sos has applications in basic research e.g. in precision spectroscopy @xcite , frequency metrology and quantum optics but could also enable the development or improvement of a number of useful practical devices in optical metrology like high resolution optical spectrum or vector analyzers , phase stable cw thz - synthesizers @xcite , high resolution , high dynamic range optical frequency domain reflectometers based on frequency scanning , optical coherence tomography @xcite or traceable range finders and laser trackers .
+ the invention of frequency combs @xcite , which consist of a broadband fixed frequency grid with well - defined frequency and phase relations between the individual comb lines , has enabled the most sophisticated sos approaches up to date @xcite .
these implementations are based on phase - locking of a single - frequency `` clean - up '' laser to an individual comb line of a frequency comb and subsequent tuning of the repetition....
And you have already written the first three sentences of the full article: we gratefully acknowledge project management support by p. leisching .
the work was funded by the german ministry of economics and technology ( zim projects kf2303709 and kf2806204 ) ..
Please generate the next two sentences of the article | |
9,653 | Suppose that you have an abstract for a scientific paper: we study a mixture of one - dimensional bosons and spinless fermions at incommensurate filling using phenomenological bosonization and green s functions techniques .
we derive the relation between the parameters of the microscopic hamiltonian and macroscopic observables .
galilean invariance results in extra constraints for the current current interactions .
we obtain the exact exponents for the various response functions , and show that superfluid fluctuations are enhanced by the effective boson - fermion density - density interaction and suppressed by the effective boson - fermion current - current interaction . in the case of a bosonized model with purely density - density interaction ,
when the effective boson - fermion density - density interaction is weak enough , the superfluid exponent of the bosons has a non - monotonous variation with the ratio of the fermion velocity to the boson velocity .
by contrast , density - wave exponent and the exponent for fermionic superfluidity are monotonous functions of the velocity ratio . .
And you have already written the first three sentences of the full article: the recent development of atom trapping technologies @xcite has led to the opening of new research fields of many - body physics . in particular , the possibility of controlling to a large degree the shape of the trapping potential has permitted the experimental realization of nearly isolated low dimensional interacting boson systems @xcite , and the observation of the bosonic mott insulator @xcite .
moreover , the use of fano - feshbach resonances @xcite allows experimentalist to control interaction strength in the low dimensional atomic gases @xcite .
this has permitted the observation of the girardeau @xcite fermionization of one - dimensional bosons with strongly repulsive interactions @xcite . from the theoretical point of view , fermions as well as bosons with repulsive interactions in one dimension are in the tomonaga - luttinger liquid state @xcite . the bosonization technique @xcite allows the description of their low - energy physics in terms of collective phonon - like modes as well as the computation of the various correlation functions ..
Please generate the next two sentences of the article | it is found that in the tomonaga - luttinger liquid state at zero temperature , only quasi - long range order ( whether superfluid or density wave ) can be obtained , with correlation functions decaying as power laws , the exponent of the power law being a rational function of the tomonaga - luttinger parameter @xmath0 .
this parameter @xmath0 depends on interaction . in the case of bosons with contact interaction |
9,654 | Suppose that you have an abstract for a scientific paper: self - assembly materials are traditionally designed so that molecular or meso - scale components form a single kind of large structure . here , we propose a scheme to create multifarious assembly mixtures " , which self - assemble many different large structures from a set of shared components .
we show that the number of multifarious structures stored in the solution of components increases rapidly with the number of different types of components . yet , each stored structure can be retrieved by tuning only a few parameters , the number of which is only weakly dependent on the size of the assembled structure .
implications for artificial and biological self - assembly are discussed . .
And you have already written the first three sentences of the full article: a classical example of self - assembly is crystallization . at low temperatures
the crystalline phase is typically stable , and thus grows spontaneously from solution through homogeneous nucleation .
if several competing crystalline phases are allowed by microscopic interactions , the efficient production of a desired phase often requires heterogeneous nucleation from a seed of this phase , with precise annealing protocols @xcite ..
Please generate the next two sentences of the article | more complex microscopic interactions may lead to a glassy phase with many competing structures ; however , it is generally impossible to control local compositions or microscopic interactions to obtain a particular structure .
recently , there has been a dramatic change in macromolecular and colloidal assembly techniques , made possible by the use of biopolymers , such as dna , to create a large variety of inter - component interactions . |
9,655 | Suppose that you have an abstract for a scientific paper: in two previous papers , i introduced superspreader ( ss ) epidemic models , offered some theoretical discussion of prevention issues , and fitted some models to data sets derived from published accounts of the ongoing mers epidemic ( concluding that a pandemic is likely ) . continuing on this theme , here i discuss prediction : whether , in a disease outbreak driven by superspreader events , a rigorous decision point meaning a declaration that a pandemic is imminent can be defined .
i show that all sources of prediction bias contribute to generating false negatives ( i.e. , discounting the chance of a pandemic when it is looming or has already started ) .
nevertheless , the statistical difficulties can be overcome by improved data gathering and use of known techniques that decrease bias .
one peculiarity of the ss epidemic is that the prediction can sometimes be made long before the actual pandemic onset , generating lead time to alert the medical community and the public .
thus modeling is useful to overcome a false sense of security arising from the long `` kindling times '' characteristic of ss epidemics and certain political / psychological factors , as well as improve the public health response . .
And you have already written the first three sentences of the full article: again i avoid the standard journal format .
the only prerequisites for reading the main text of this paper are some familiarity with common statistical terms or phrases such as `` bias '' and `` maximum - likelihood estimation , '' which i assume most readers will recall from a college statistics course or will look up on wikipedia .
i will relegate the statistical heavy - lifting to an appendix ..
Please generate the next two sentences of the article | perhaps the single most important contribution a mathematical modeler can make for public health would be to invent a tool that could predict the occurrence of a deadly world - wide pandemic of an infectious disease . as is well - known , most such diseases derive from zoonotic transmission events ( meaning from an animal host in which the disease organism is endemic , or is currently causing an epizootic , to humans ) ; examples include plague , influenza , ebola , hiv , sars , and mers .
when a pathogen jumps species there is a likely requirement of certain genetic modifications before it can cause efficient transmission in the new host population . |
9,656 | Suppose that you have an abstract for a scientific paper: we measured the electrical resistivity from 2k up to 900k on high quality single crystals of lu@xmath0ir@xmath1si@xmath2 .
a clear thermal hysteresis was found at the onset of the charge density wave ( cdw ) , evidencing the first order nature of the transition . when tantalum is included in the compound ,
the cdw is destroyed and the superconducting critical temperature is enhanced .
finally , we present specific heat and magnetic penetration depth in the meissner state . we show that the superconducting properties are very close to a weak coupling bcs superconductor . .
And you have already written the first three sentences of the full article: in many strongly correlated electronic systems , superconductivity seems to be linked to the vicinity of an electronic or magnetic instability with a characteristic phase diagram . currently , there is a growing interest on the systems where this electronic instability is a charge density wave .
superconductivity and cdw share the electron - phonon interaction in terms of microscopical mechanism .
these kind of competitions were also revived with the recent and quasi - systematic observation of a superconducting pocket at the border of the cdw in the dichalcogenides [ 1,2 ] ..
Please generate the next two sentences of the article | these superconductors can show deviations from the weak coupling bcs theory , which raises the question of the interplay between the two orders .
the cdw opens a gap on parts of the fermi surface and can be at the origin of the modification of the superconducting gap structure . |
9,657 | Suppose that you have an abstract for a scientific paper: we study the two - body bound and scattering states of two particles in a one dimensional optical lattice in the presence of a coherent coupling between two internal atomic levels . due to the interplay between periodic potential , interactions and coherent coupling , the internal structure of the bound states depends on their center of mass momentum .
this phenomenon corresponds to an effective momentum - dependent magnetic field for the dimer pseudo - spin , which could be observed in a chirping of the precession frequency during bloch oscillations .
the essence of this effect can be easily interpreted in terms of an effective bound state hamiltonian .
moreover for indistinguishable bosons , the two - body eigenstates can present simultaneously attractive and repulsive bound - state nature or even bound and scattering properties . .
And you have already written the first three sentences of the full article: in the recent years it has been demonstrated that ultracold atoms loaded in optical lattices provide an ideal realization of lattice hamiltonians @xcite .
the control of the system parameters , in particular of the ratio between interactions and kinetic energy , has allowed the experimental achievement of the most famous mott insulator to superfluid phase transition in 2002 @xcite . from there on , the number of implementations of hubbard - like models using cold gases in optical lattices has undergone an incredible growth ( see , e.g. , @xcite ) : it is now possible to mimic single- and multi - species bose and fermi - hubbard models , extended hubbard models by using dipolar gases @xcite , and spin chain models @xcite .
more recently , hubbard models characterised by non - trivial topology , synthetic magnetic field , artificial gauges @xcite , or synthetic dimensions @xcite have been realized ..
Please generate the next two sentences of the article | most of the theoretical studies on lattice hamiltonians regard many - body or single particle properties , especially in the case of non trivial topology . on the other hand ,
lattice hamiltonians show interesting features also as far as the few body physics is concerned . indeed , |
9,658 | Suppose that you have an abstract for a scientific paper: we derive the equations that describe adsorption of diffusing particles onto a surface followed by additional surface kinetic steps before being transported across the interface .
multistage surface kinetics occurs during membrane protein insertion , cell signaling , and the infection of cells by virus particles .
for example , viral entry into healthy cells is possible only after a series of receptor and coreceptor binding events occur at the cellular surface .
we couple the diffusion of particles in the bulk phase with the multistage surface kinetics and derive an effective , integro - differential boundary condition that contains a memory kernel embodying the delay induced by the surface reactions .
this boundary condition takes the form of a singular perturbation problem in the limit where particle - surface interactions are short - ranged .
moreover , depending on the surface kinetics , the delay kernel induces a nonmonotonic , transient replenishment of the bulk particle concentration near the interface .
the approach generalizes that of ward and tordai @xcite and diamant and andelman @xcite to include surface kinetics , giving rise to qualitatively new behaviors .
our analysis suggests a simple scheme by which stochastic surface reactions may be coupled to deterministic bulk diffusion . .
And you have already written the first three sentences of the full article: the kinetics of surface particle adsorption and of transport through interfaces play a key role in surfactant phenomena @xcite , membrane biology and cell signaling @xcite , marine layer oceanography @xcite , and other biological and chemical processes .
particle adsorption may fundamentally alter the physical and chemical properties of the interface , and it is crucial to understand both equilibrium and dynamical properties of the adsorbed layers @xcite . in the seminal work of ward and tordai @xcite ,
a bulk phase acting as a reservoir of particles is physically limited by an empty surface onto which the particles can adsorb ..
Please generate the next two sentences of the article | particles are assumed to lower their free energy with respect to the bulk phase by irreversibly and instantaneously adsorbing onto the interface . under these conditions , the total concentration of adsorbed particles
may be estimated in relation to measurable interfacial properties , such as the dynamic surface tension . |
9,659 | Suppose that you have an abstract for a scientific paper: this paper describes a novel approach to medical diagnosis based on the sp theory of computing and cognition .
the main attractions of this approach are : a format for representing diseases that is simple and intuitive ; an ability to cope with errors and uncertainties in diagnostic information ; the simplicity of storing statistical information as frequencies of occurrence of diseases ; a method for evaluating alternative diagnostic hypotheses that yields true probabilities ; and a framework that should facilitate unsupervised learning of medical knowledge and the integration of medical diagnosis with other ai applications .
_ keywords : _ medical diagnosis , information compression , multiple alignment , sp theory , pattern recognition , causal reasoning . .
And you have already written the first three sentences of the full article: the problem of providing computational support for medical diagnosis has been approached from many directions including logical reasoning , fuzzy logic , set theory , rough set theory , if - then rules , bayesian networks , classical parametric and non - parametric statistics , artificial neural networks , case - based reasoning , support vector machines , perceptrons , possibility theory , and more , as well as various aggregations or combinations of methods @xcite .
this paper describes a novel approach to diagnosis based on the sp theory of computing and cognition ( described below ) .
the main attractions of this approach are : * a format for representing diseases that is simple and intuitive . * an ability to cope with errors and uncertainties in diagnostic information . * the simplicity of storing statistical information as frequencies rather than conditional probabilities . * a method for evaluating alternative diagnostic hypotheses that yields true probabilities . * a framework that should facilitate unsupervised learning of medical knowledge and the integration of medical diagnosis with other ai applications ..
Please generate the next two sentences of the article | _ it must be stressed that the primary purpose of this paper is conceptual _ : to describe an approach to medical diagnosis that is significantly different from the main alternatives and with potential advantages compared with those alternatives .
although a prototype of the proposed new system exists , it is not yet a shrink - wrapped software system that is ready for immediate application . like any other diagnostic system , the sp system must be equipped with a body of relevant knowledge and the creation of such a body of knowledge ( by automatic learning or by ` knowledge elicitation ' from experts ) is a major undertaking in its own right . |
9,660 | Suppose that you have an abstract for a scientific paper: the appearance of eruptive space plasma processes , e.g. , in eruptive flares as observed in the solar atmosphere , is usually assumed to be caused by magnetic reconnection .
the process of magnetic reconnection is often connected with singular points of the magnetic field .
we therefore analyse the system of stationary resistive / non - ideal magnetohydrodynamics ( mhd ) in the vicinity of singular points of flow and field to determine the boundary between reconnection solutions and non - reconnective solutions .
we find conditions to enable the plasma to cross the magnetic separatrices also inside the current sheet , close to the current maximum .
the results provide us with the topological and geometrical skeleton of the resistive mhd fields .
we therefore have to perform a local analysis of almost all non - ideal mhd solutions without a specific non - idealness .
we use taylor expansions of the magnetic field , the velocity field and all other physical quantities , including the non - idealness , and with the method of a comparison of the coefficients , the non - linear resistive mhd system is solved analytically . in the vicinity of a stagnation point , it is reasonable to assume that the density is constant .
we find that the electric field has to be zero and that the non - ideal term / resistivity has to depend on the spatial coordinates and can not be constant , otherwise it has to be zero everywhere .
it turns out that not every non - ideal flow is a reconnective flow and that pure resistive / non - ideal mhd only allows for such reconnection - like solutions , even if the non - idealness is localized to the region around the magnetic null point .
it is necessary that the flow close to the magnetic x - point is also of x - point type to guarantee positive dissipation of energy and annihilation of magnetic flux .
if the non - idealness has only a one - dimensional , sheet - like structure , only one separatrix line can be crossed by the plasma flow , similar to reconnective....
And you have already written the first three sentences of the full article: magnetic reconnection is thought to be a process , being responsible for many eruptive plasma phenomena in space plasmas and astrophysical plasmas , like geomagnetical substorms or eruptive flares .
although magnetic reconnection in two dimensions ( 2d ) is fairly well understood , e.g. , see the comments in , it would be interesting to have more detailed informations about the topological and geometrical structure of flow and field lines in the vicinity of the singular points of plasma flow and magnetic field .
classical reconnection scenarios , see or sweet - parker model ( see , e.g. , ) propose a magnetic null point and a stagnation point flow into the diffusion region , i.e. the stagnation point is inside this diffusion region . where the first to analyse the case of incompressible 2d mhd with constant resistivity ..
Please generate the next two sentences of the article | it turned out that either the magnetic field must be of higher order in the spatial variables @xmath0 and @xmath1 or that there is no stagnation point flow , but a shear flow .
therefore their result is , that the classical hyperbolic stagnation point flow needs higher order terms , concerning the spatial variables ( @xmath0 and @xmath1 ) . |
9,661 | Suppose that you have an abstract for a scientific paper: let @xmath0 be a two - sided standard brownian motion . an _ unbiased shift
_ of @xmath1 is a random time @xmath2 , which is a measurable function of @xmath1 , such that @xmath3 is a brownian motion independent of @xmath4 .
we characterise unbiased shifts in terms of allocation rules balancing additive functionals of @xmath1 . for any probability distribution @xmath5 on @xmath6
we construct a stopping time @xmath7 with the above properties such that @xmath4 has distribution @xmath5 .
in particular , we show that if we travel in time according to the clock of local time we always see a two - sided brownian motion
. a crucial ingredient of our approach is a new theorem on the existence of allocation rules balancing jointly stationary diffuse random measures on @xmath6 .
we also study moment and minimality properties of unbiased shifts . _ 2000 mathematics subject classification . _ 60j65 ; 60g57 ; 60g55 . _
key words and phrases .
_ brownian motion , local time , unbiased shift , allocation rule , palm measure , random measure , skorokhod embedding . .
And you have already written the first three sentences of the full article: let @xmath0 be a two - sided standard brownian motion in @xmath6 having @xmath8 .
if @xmath7 is a stopping time with respect to the filtration @xmath9 , then the shifted process @xmath10 is a one - sided brownian motion independent of @xmath4 .
however , the two - sided shifted process @xmath11 need not be a two - sided brownian motion ..
Please generate the next two sentences of the article | moreover , the example of a fixed time shows that even if it is , it need not be independent of @xmath4 .
we call a random time @xmath2 an _ unbiased shift _ ( of a two - sided brownian motion ) if @xmath2 is a measurable function of @xmath1 and @xmath11 is a two - sided brownian motion , independent of @xmath4 . |
9,662 | Suppose that you have an abstract for a scientific paper: we report optical and near - infrared spectra of the central star of the radio source g79.29 + 0.46 , a candidate luminous blue variable . the spectra contain numerous narrow ( fwhm @xmath0 100 kms@xmath1 ) emission lines of which the low - lying hydrogen lines are the strongest , and resemble spectra of other lbvc s and b[e ] supergiants .
a few prominent infrared lines are unidentified .
the terminal wind speed is determined from h@xmath2 to be 110 kms@xmath1 .
the strength of h@xmath2 implies the presence of a very dense wind .
extended emission from h@xmath2 and [ nii ] was detected but appears to be associated with the cygnus x region rather than the radio source .
both diffuse interstellar bands and interstellar absorption lines are present in the optical spectrum of the central star , suggesting that there are both diffuse and molecular cloud components to the extinction and implying a minimum distance of 1 kpc and minimum luminosity of @xmath310@xmath4l@xmath5 for the star .
the new spectra and their analysis indicate a low excitation , dense , and slowly expanding wind and support the lbvc classification . .
And you have already written the first three sentences of the full article: many gaps exist in the understanding of the post - main sequence evolution of the most massive ( @xmath640 m@xmath5 ) stars , due in large part to the small number of such stars identified as being in this evolutionary phase .
it is known that during part of the post - main sequence phase , identified as the luminous blue variable ( lbv ) stage ( conti 1984 ) , these stars lose a large amount of mass in a short time interval ( e.g. chiosi & maeder 1986 ) .
the identifying characteristics of an lbv in addition to its blue colors are ( 1 ) a mass loss rate of ( @xmath7 m@xmath5yr@xmath1 ) , ( 2 ) a low wind velocity of no more than a few hundred kms@xmath1 , ( 3 ) photometric variations of up to 2 magnitudes on time - scales ranging from months to decades , and ( 4 ) the presence of a circumstellar ( and sometimes bipolar ) nebula ( nota & clampin 1997 ) . less than a dozen confirmed lbvs are known in our galaxy . however , in recent years a number of lbv candidates ( lbvc s ) have been found ..
Please generate the next two sentences of the article | candidates generally have both of the first two characteristics listed above and one of the other two ( for reviews see nota & lamers 1997 ) .
one recently discovered lbvc is the central star of the radio shell g79.29 + 0.46 ( higgs et al . 1994 , hereafter hwl ; and waters et al . |
9,663 | Suppose that you have an abstract for a scientific paper: we investigate the limits on the higgs mass in variations of split supersymmetry , where the boundary value of the higgs quartic coupling at the susy breaking scale ( @xmath0 ) is allowed to deviate from its value in the minimal model of arkani - hamed and dimopoulos .
we show that it is possible for @xmath1 to be negative and use vacuum stability to put a lower bound on this coupling , and hence on the mass of the physical higgs .
we also use the requirement of perturbativity of all couplings up to the cutoff to determine an upper limit for the higgs mass in models which are further modified by additional matter content . for @xmath2 gev
we find @xmath3 gev @xmath4 gev if the new matter is not coupled to any standard model field ; and @xmath3 gev @xmath5 gev if it has yukawa couplings to the higgs . .
And you have already written the first three sentences of the full article: the quest for a natural way to break electroweak symmetry has long been the central motivation for constructing theories for physics beyond the standard model ( sm ) at the tev scale .
however , the same logic applied to the even more severe fine - tuning problem associated with the cosmological constant would have predicted new physics near @xmath6 ev , which we have no evidence for .
this suggests the possibility that our notions of naturalness are misleading , and that other fine - tuning mechanisms may be at work in nature . eliminating the use of naturalness as a guiding principle for model - building allows for some drastic changes to particle physics lore ..
Please generate the next two sentences of the article | arkani - hamed and dimopoulos have recently argued for a theory with `` split '' supersymmetry @xcite ( also @xcite ) . in this model
the `` structure '' @xcite and `` atomic '' @xcite principles were used to explain the smallness of uv sensitive parameters ; namely the cosmological constant and the higgs vacuum expectation value . |
9,664 | Suppose that you have an abstract for a scientific paper: we present a new optical polarimetric catalog for the small magellanic cloud ( smc ) .
it contains a total of 7207 stars , located in the northeast ( ne ) and wing sections of the smc and part of the magellanic bridge .
this new catalog is a significant improvement compared to previous polarimetric catalogs for the smc .
we used it to study the sky - projected interstellar magnetic field structure of the smc .
three trends were observed for the ordered magnetic field direction at position angles ( pas ) of ( @xmath0 ) , ( @xmath1 ) , and ( @xmath2 ) .
our results suggest the existence of an ordered magnetic field aligned with the magellanic bridge direction and smc s bar in the ne region , which have pas roughly at @xmath3 and @xmath4 , respectively . however , the overall magnetic field structure is fairly complex .
the trends at @xmath5 and @xmath6 may be correlated with the smc s bimodal structure , observed in cepheids distances and hi velocities .
we derived a value of @xmath7 g for the ordered sky - projected magnetic field , and @xmath8 g for the turbulent magnetic field .
this estimate of @xmath9 is significantly larger ( by a factor of @xmath10 ) than the line of sight field derived from faraday rotation observations , suggesting that most of the ordered field component is on the plane of the sky . a turbulent magnetic field stronger than the ordered field agrees with observed estimates for other irregular and spiral galaxies . for the smc
the @xmath11 ratio is closer to what is observed for our galaxy than other irregular dwarf galaxies . .
And you have already written the first three sentences of the full article: the small magellanic cloud ( smc ) and the large magellanic cloud ( lmc ) are gas rich irregular galaxies and satellites of the milky way ( mw ) . given the proximity to the galaxy and their high galactic latitude , the magellanic clouds ( mcs ) are perfect laboratories for extragalactic studies , since the light emitted from them is not much attenuated by the dust present in the galactic disk .
these objects are highly studied , motivated by the fact that , through understanding them , we can also better comprehend , for instance , galaxy evolution from high redshifts to now ; the structure of irregular dwarf galaxies ; the interstellar medium ( ism ) content at the external parts of huge spiral galaxies ; star formation at low metalicity environments ; dwarf galaxies in interaction ; and the relation of satellite galaxies with their hosts .
the mcs are low metalicity galaxies @xmath12 and @xmath13 for the lmc and smc , respectively @xcite ..
Please generate the next two sentences of the article | this peculiarity makes their ism particularly different from the one of our galaxy . among the major differences , we can point out the high gas - to - dust ratio @xcite and the submm excess emission @xcite .
the smc consists of two main features : bar and wing . |
9,665 | Suppose that you have an abstract for a scientific paper: genetic switch systems with mutual repression of two transcription factors are studied using deterministic methods ( rate equations ) and stochastic methods ( the master equation and monte carlo simulations ) .
these systems exhibit bistability , namely two stable states such that spontaneous transitions between them are rare . induced transitions may take place as a result of an external stimulus .
we study several variants of the genetic switch and examine the effects of cooperative binding , exclusive binding , protein - protein interactions and degradation of bound repressors .
we identify the range of parameters in which bistability takes place , enabling the system to function as a switch .
numerous studies have concluded that cooperative binding is a necessary condition for the emergence of bistability in these systems .
we show that a suitable combination of network structure and stochastic effects gives rise to bistability even without cooperative binding .
the average time between spontaneous transitions is evaluated as a function of the biological parameters . .
And you have already written the first three sentences of the full article: recent advances in quantitative measurements of gene expression at the single - cell level @xcite have brought new insight on the importance of stochastic fluctuations in genetic circuits @xcite .
the role of fluctuations is enhanced due to the discrete nature of the transcription factors and their binding sites , which may appear in low copy numbers @xcite . as a result
, populations of genetically identical cells may show significant variability ..
Please generate the next two sentences of the article | stochastic behavior may invoke oscillations @xcite and spatio - temporal patterns @xcite , which are unaccounted for by macroscopic chemical rate equations .
genetic circuits with feedback mechanisms may exhibit bistability , namely , two distinct stable states which can be switched by an external signal @xcite . |
9,666 | Suppose that you have an abstract for a scientific paper: we present an analysis of two strongly lensed galaxies at @xmath0 and @xmath1 for which multi - band photometric and spectroscopic observations are available . for one source
the data include recent hst and spitzer observations .
using an sed fitting technique considering a number of parameters ( various libraries of empirical and theoretical template spectra , variable extinction and extinction laws ) we attempt to constrain the properties of their stellar populations ( age , star formation history , mass ) and their intrinsic ly@xmath2 emission .
the following main results are obtained for the individual galaxies : * * triple arc in abell 2218 , probable @xmath1 galaxy : * the most likely redshift of this source is @xmath3 6.07.2 taking into account both our photometric determination and lensing considerations .
sed fits indicate generally a low extinction ( @xmath4 ) but do not strongly constrain the star formation ( sf ) history .
best fits have typical ages of @xmath5 3 to 400 myr . a reasonable maximum age of ( 250650 ) myr ( 1 @xmath6 interval ) can be estimated .
however , the apparent 4000 break observed recently from combination of irac / spitzer and hst observations , can also equally well be reproduced with the template of a young ( @xmath5 35 myr ) burst where strong restframe optical emission lines enhance the 3.6 and 4.5 fluxes .
the estimated sfr is typically @xmath5 1 for a salpeter imf from 1 - 100 , in agreement with previous estimates .
the unknowns on the age and star formation history could easily explain the apparent absence of ly@xmath2 in this galaxy . *
* abell 370 hcm 6a : * the available ly@xmath2 and continuum observations indicate basically two possible solutions : 1 ) a young burst or ongoing constant sf with non - negligible extinction or 2 ) a composite young + `` old '' stellar population . in the first case one obtains a best fit @xmath7 , or @xmath8 0.51.8 at a 1 @xmath6 level . in consequence
we obtain sfr @xmath5 1141 , higher than earlier....
And you have already written the first three sentences of the full article: little is known about the stellar properties , extinction , and the expected intrinsic ly@xmath2 emission of distant , high redshift galaxies .
indeed , although it has in the recent past become possible through various techniques to detect already sizeable numbers of galaxies at @xmath10 ( see e.g. the reviews of taniguchi et al .
2003 and spinrad 2004 ) the information available on these objects remains generally scant ..
Please generate the next two sentences of the article | for example , in many cases the galaxies are just detected in two photometric bands and ly@xmath2 line emission , when present , serves to determine the spectroscopic redshift ( e.g. bremer 2004 , dickinson 2004 , bunker 2004 ) .
then the photometry is basically used to estimate the star formation rate ( sfr ) assuming standard conversion factors between the uv restframe light and the sfr , and nothing is known about the extinction , and the properties of the stellar population ( such as age , detailed star formation histories etc . ) at higher redshift ( @xmath11 ) even less information is generally available ( but see a recent study of eyles 2005 on two @xmath12 galaxies observed with hst and spitzer ) . |
9,667 | Suppose that you have an abstract for a scientific paper: we report radio observations of two stripped - envelope supernovae ( sne ) , 2010o and 2010p , which exploded within a few days of each other in the luminous infrared galaxy arp299 .
whilst sn2010o remains undetected at radio frequencies , sn2010p was detected ( with an astrometric accuracy better than 1milli arcsec in position ) in its optically thin phase in epochs ranging from @xmath0 to @xmath1yr after its explosion date , indicating a very slow radio evolution and a strong interaction of the sn ejecta with the circumstellar medium .
our late - time radio observations toward sn2010p probe the dense circumstellar envelope of this sn , and imply @xmath2 / v_{\rmn{wind } } [ 10\,{\,\mbox{\ensuremath{\rmn{km\,s^{-1 } } } } } { } ] = ( 3.0$]5.1)@xmath3 , with a 5ghz peak luminosity of @xmath4@xmath5 on day @xmath6464 after explosion .
this is consistent with a type iib classification for sn2010p , making it the most distant and most slowly evolving type iib radio sn detected to date .
[ firstpage ] supernovae : general supernovae : individual : sn2010o supernovae : individual : sn2010p .
And you have already written the first three sentences of the full article: core - collapse supernovae ( ccsne ) are the signposts of recent massive star formation .
since much of the massive star formation is embedded in dust , a substantial fraction of the ccsne in the universe will remain hidden in optical searches @xcite .
this is particularly true in the case of star formation taking place in the dusty environments of luminous ( @xmath7)@xmath8 $ ] . ] , and ultra - luminous ( @xmath9 ) infrared ( ir ) galaxies ( lirgs and ulirgs , respectively ) , which dominates the star formation rate density at @xmath10 ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | in many lirgs , the bulk of star formation occurs within their circumnuclear regions ( @xmath11kpc ) , so that the need for high - resolution observations becomes crucial in the detection and study of ccsne therein .
the synergy between high resolution radio and near - infrared ( nir ) _ k_-band ( where the extinction is 10 times lower than in the optical ) observations is currently being used to help build a complete picture of the supernova ( sn ) activity in dusty starbursts and lirgs . |
9,668 | Suppose that you have an abstract for a scientific paper: in this paper we propose and study a spatial diffusion model for the control of anthracnose disease in a bounded domain .
the model is a generalization of the one previously developed in @xcite .
we use the model to simulate two different types of control strategies against anthracnose disease .
strategies that employ chemical fungicides are modeled using a continuous control function ; while strategies that rely on cultivational practices ( such as pruning and removal of mummified fruits ) are modeled with a control function which is discrete in time ( though not in space ) . under weak smoothness conditions on parameters we demonstrate the well - posedness of the model by verifying existence and uniqueness of the solution for given initial conditions .
we also show that the set @xmath0 $ ] is positively invariant . we first study control by pulse strategy only , then analyze the simultaneous use of continuous and pulse strategies . in each case
we specify a cost functional to be minimized , and we demonstrate the existence of optimal control strategies that can be evaluated numerically using the gradient method presented in @xcite . we discuss the results of numerical simulations both for a spatially - averaged version of the model and for the full model .
* keywords * anthracnose modelling , nonlinear systems , impulsive pde , optimal control . * ams classification * 49j20 , 49j15 , 92d30 , 92d40 . .
And you have already written the first three sentences of the full article: anthracnose is a phytopathology which attacks several commercial tropical crops such as coffee .
the anthracnose of coffee is known under the name coffee berry disease ( cbd ) and its pathogen is the _ colletotrichum _ _ kahawae _ , an ascomycete fungus .
the literature on anthracnose pathosystem is extensive @xcite ..
Please generate the next two sentences of the article | there have been several attempts to model the spread of cbd and to identify efficient control strategies @xcite .
possible control methods include genetic methods @xcite , biological control @xcite , chemical control @xcite and cultivational practices @xcite . |
9,669 | Suppose that you have an abstract for a scientific paper: we discuss the role plasma injection plays in the formation of outflows in kerr spacetime . using a model for the double flow established in the polar region of a rotating black hole , we study the interplay between the different processes that can power the outflow . in particular , we find two types of flows with distinct properties that depend on the rate at which energy is deposited in the magnetosphere .
we discuss the implications of this result for gamma ray bursts outflows . .
And you have already written the first three sentences of the full article: accreting black holes are thought to power the relativistic jets that form in active galactic nuclei ( agns ) , microquasars , and gamma - ray bursts ( grbs ) .
a plausible production mechanism for those jets is magnetic extraction of the spin energy of a kerr black hole@xcite .
a key feature of this process is a double trans - magnetosonic plasma flow which is launched from a stagnation radius located between the inner and outer light surfaces , and sustained by a plasma source in the magnetosphere . in general , there is a range of plasma injection rates within which the blandford - znajek ( bz ) process can be activated ; it has to be sufficiently high to provide the charge density required to establish an mhd flow , but low enough to avoid overloading of magnetic field lines that leads to a shutdown of the bz process ..
Please generate the next two sentences of the article | the nature of the plasma source in most of the relativistic systems mentioned above is not well understood yet . in agns
the problem seems to be how to inject enough charged particles on open magnetic field lines . |
9,670 | Suppose that you have an abstract for a scientific paper: we investigate the connection between radix representations for @xmath0 and self - affine tilings of @xmath1 .
we apply our results to show that haar - like multivariable wavelets exist for all dilation matrices that are sufficie ntly large . .
And you have already written the first three sentences of the full article: we investigate the connections between radix representations for @xmath0 , self - affine tilings of @xmath1 , and haar - like scaling functions for multiresolution analyses and associated wavelet sets . in a separate paper
, we investigate the idea , also introduced by jeong @xcite , of radix representations for vectors in @xmath0 , or general point lattices @xmath2 ( @xmath3 a nondegenerate @xmath4 matrix ) @xcite .
we wish to consider expanding matrices which preserve @xmath5 . without loss of generality.
Please generate the next two sentences of the article | , we may assume @xmath6 .
a matrix which preserves @xmath0 must have integer entries . |
9,671 | Suppose that you have an abstract for a scientific paper: the problem of the time required for a diffusing molecule , within a large bounded domain , to first locate a small target is prevalent in biological modeling . here
we study this problem for a small spherical target .
we develop uniform in time asymptotic expansions in the target radius of the solution to the corresponding diffusion equation .
our approach is based on combining expansions of a long - time approximation of the solution , involving the first eigenvalue and eigenfunction of the laplacian , with expansions of a short - time correction calculated by pseudopotential approximation .
these expansions allow the calculation of corresponding expansions of the first passage time density for the diffusing molecule to find the target .
we demonstrate the accuracy of our method in approximating the first passage time density and related statistics for the spherically symmetric problem where the domain is a large concentric sphere about a small target centered at the origin . .
And you have already written the first three sentences of the full article: diffusion of a molecule to a spherical trap is a classical problem important in chemical kinetics . in an unbounded domain , the problem reduces to the smoluchowski theory of reaction kinetics . in the context of biological processes , intracellular transport of biomolecules and chemical reactions
occur within closed domains with complex geometries @xcite . as a first passage time problem , this is closely related to the narrow escape problem , where a diffusing molecule escapes a closed domain through a small opening on the boundary , and the long time behavior has been studied using matched asymptotics @xcite .
there are many examples of this type of first passage time problem in biological modeling , including transport of receptors on the plasma membrane of a dendrite @xcite , intracellular virus trafficking @xcite , molecular motor transport @xcite , binding of a transcription factor to a segment of dna within a nucleus @xcite , and export of newly transcribed mrna through nuclear pores @xcite ..
Please generate the next two sentences of the article | consider a bounded domain @xmath0 , containing a small , absorbing spherical trap , @xmath1 , with radius @xmath2 centered at @xmath3 .
we denote by @xmath4 the exterior boundary surface to @xmath5 , and by @xmath6 the exterior boundary to @xmath7 . |
9,672 | Suppose that you have an abstract for a scientific paper: we combine iram plateau de bure interferometer and _ herschel _ pacs and spire measurements to study the dust and gas contents of high - redshift star forming galaxies .
we present new observations for a sample of 17 lensed galaxies at @xmath0 , which allow us to directly probe the cold ism of normal star - forming galaxies with stellar masses of @xmath1@xmath2 , a regime otherwise not ( yet ) accessible by individual detections in _ herschel _ and molecular gas studies .
the lensed galaxies are combined with reference samples of sub - millimeter and normal @xmath3 star - forming galaxies with similar far - infrared photometry to study the gas and dust properties of galaxies in the sfr-@xmath4-redshift parameter space .
the mean gas depletion timescale of main sequence galaxies at @xmath5 is measured to be only @xmath6myr , a factor of @xmath7 ( @xmath8 ) shorter than at @xmath9 ( @xmath10 ) , in agreement with a @xmath11 scaling .
the mean gas mass fraction at @xmath12 is @xmath13 ( 44% after incompleteness correction ) , suggesting a flattening or even a reversal of the trend of increasing gas fractions with redshift recently observed up to @xmath14 .
the depletion timescale and gas fractions of the @xmath5 normal star - forming galaxies can be explained under the equilibrium model " for galaxy evolution , in which the gas reservoir of galaxies is the primary driver of the redshift evolution of specific star formation rates . due to their high star formation efficiencies and low metallicities , the @xmath5 lensed galaxies have warm dust despite being located on the star formation main sequence . at fixed metallicity
, they also have a gas - to - dust ratio 1.7 times larger than observed locally when using the same standard techniques , suggesting that applying the local calibration of the @xmath15-metallicity relation to infer the molecular gas mass of high redshift galaxies may lead to systematic differences with co - based estimates . .
And you have already written the first three sentences of the full article: most star - forming galaxies follow a relation between their stellar masses and star formation rates that has been well characterized up to @xmath16 ( e.g. * ? ? ?
* ; * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
the very existence and tightness of this relation suggests that these galaxies live in a state of equilibrium where their ability to form stars is regulated by the availability of gas and the amount of material they return to the circum - galactic medium through outflows ( e.g. * ? ? ? |
9,673 | Suppose that you have an abstract for a scientific paper: we present deep near - infrared @xmath0 , @xmath1 , and @xmath2 band imaging of a field around @xmath3 , a massive cluster at @xmath4 .
the observations were carried out with the isaac instrument at the eso very large telescope ( vlt ) as part of the faint infrared extragalactic survey ( fires ) .
the total integration time amounts to 25.9 h in @xmath0 , 24.4 h in @xmath1 , and 26.5 h in @xmath2 band , divided nearly equally between four pointings covering @xmath5 .
the @xmath6 total limiting ab magnitudes for point sources from the shallowest to the deepest pointing are @xmath7 , @xmath8 , and @xmath9 .
the effective spatial resolution of the coadded images has @xmath10 , @xmath11 , and @xmath12 in @xmath0 , @xmath1 , and @xmath2 , respectively .
we complemented the isaac data with deep optical imaging using existing hubble space telescope wfpc2 mosaics through the f606w and f814w filters and additional @xmath13 , @xmath14 , and @xmath15 band observations we obtained with the vlt fors1 instrument .
we constructed a @xmath2-band limited multicolour source catalogue down to @xmath16 ( @xmath17 for point sources ) .
the catalogue contains 1858 objects , of which 1663 have eight - band photometry .
we describe the observations , data reduction , source detection , and photometric measurements method .
we also present the number counts , colour distributions , and photometric redshifts @xmath18 of the catalogue sources .
we find that our @xmath2-band counts at the faint end @xmath19 , with slope @xmath20 , lie at the flatter end of published counts in other deep fields and are consistent with those we derived previously in the hubble deep field south ( hdf - s ) , the other fires field .
spectroscopic redshifts @xmath21 are available for @xmath22 sources in the @xmath3 field ; comparison between the @xmath18 and @xmath21 show very good agreement , with @xmath23 .
the @xmath3 field observations complement our hdf - s data set with nearly five times larger area at @xmath24 brighter....
And you have already written the first three sentences of the full article: deep imaging surveys for high redshift studies have , in recent years , been carried out over an increasing range of wavelengths from the x - ray to the radio regimes .
an important motivation is the recognition that surveys at any given wavelength range may provide an incomplete and biased census of high redshift galaxy populations .
moreover , a multi - wavelength approach is highly desirable to assess the nature of and establish links between high redshift samples selected at various wavelengths , and to constrain the properties of their stars and gas contents as indicators of their evolutionary state ..
Please generate the next two sentences of the article | deep surveys at near - infrared wavelengths ( nir ; @xmath25 ) have emerged as an important way to investigate the high redshift universe ( see , e.g. , @xcite for a review , and references therein ) .
nir observations allow one to access the rest - frame optical light of galaxies at @xmath26 . |
9,674 | Suppose that you have an abstract for a scientific paper: the estimate of free energy changes based on bennett s acceptance ratio method is examined in several limiting cases and compared with other estimates based on the jarzynski equality and on the crooks relation . while the absolute amount of dissipated work , defined as the surplus of average work over the free energy difference , limits the practical applicability of jarzynski s and crooks methods , the reliability of bennett s approach is restricted by the difference of the dissipated works in the forward and the backward process .
we illustrate these points by considering a gaussian chain and a hairpin chain which both are extended during the forward and accordingly compressed during the backward protocol .
the reliability of the crooks relation predominantly depends on the sample size ; for the jarzynski estimator the slowness of the work protocol is crucial , and the bennett method is shown to give precise estimates irrespective of the pulling speed and sample size as long as the dissipated works are the same for the forward and the backward process as it is the case for gaussian work distributions . with an increasing dissipated work difference the bennett estimator also acquires a bias which increases roughly in proportion to this difference .
a substantial simplification of the bennett estimator is provided by the 1/2-formula which expresses the free energy difference by the algebraic average of the jarzynski estimates for the forward and the backward processes .
it agrees with the bennett estimate in all cases when the jarzynski and the crooks estimates fail to give reliable results . .
And you have already written the first three sentences of the full article: in studying the thermodynamic state of a physical system , the free energy @xmath0 is a quantity of fundamental importance .
it describes the equilibrium properties of systems that may exchange energy with their environments .
formally , it is related to the internal energy , @xmath1 , by a legendre transform @xmath2 , where @xmath3 is the temperature and @xmath4 the entropy ..
Please generate the next two sentences of the article | the free energy is a state function and hence , for any process connecting two equilibrium states , the respective change of the free energy @xmath5 , solely depends on the final and initial states without regard to the particular process connecting them .
in contrast , the work @xmath6 done on the system and the heat @xmath7 exchanged with the environment are process - dependent . yet , their sum yielding the change in internal energy , @xmath8 , does not depend on the details of the path connecting the final with the initial state . |
9,675 | Suppose that you have an abstract for a scientific paper: we study a @xmath0-dimensional kaluza - klein cosmology with a robertson - walker type metric having two scale factors @xmath1 and @xmath2 , corresponding to @xmath3-dimensional internal space and 4-dimensional universe , respectively . by introducing an exotic matter in the form of perfect fluid with an special equation of state , as the space - time part of the higher dimensional energy - momentum tensor
, a four dimensional effective decaying cosmological term appears as @xmath4 with @xmath5 , playing the role of an evolving dark energy in the universe . by taking @xmath6 , which has some interesting implications in reconciling observations with inflationary models and
is consistent with quantum tunneling , the resulting einstein s field equations yield the exponential solutions for the scale factors @xmath1 and @xmath2 .
these exponential behaviors may account for the dynamical compactification of extra dimensions and the accelerating expansion of the 4-dimensional universe in terms of hubble parameter , @xmath7 .
the acceleration of the universe may be explained by the negative pressure of the exotic matter .
it is shown that the rate of compactification of higher dimensions as well as expansion of 4-dimensional universe depends on the dimension , @xmath3 .
we then obtain the corresponding wheeler - dewitt equation and find the general exact solutions in @xmath3-dimensions .
a good correspondence between the solutions of classical einstein s equations and the solutions of quantum wheeler - dewitt equation in any dimension , @xmath3 , is obtained based on hartle s point of view concerning the classical limits of quantum cosmology .
-0.75 in .
And you have already written the first three sentences of the full article: cosmological models with a cosmological term @xmath8 are currently serious candidates to describe the dynamics of our four dimensional universe .
the history of cosmological term dates back to einstein , and its original role was to allow static homogeneous solutions to einstein s equations in the presence of matter which turned out to be unnecessary when the expansion of the universe was discovered .
however , particle physicists then realized that the non - vanishing cosmological constant can be interpreted as a measure of the energy density of the vacuum which turned out to be the sum of a number of apparently disjoint contributions of quantum fields . in fact , a dynamical characteristic for the vacuum energy density ( cosmological term ) was attributed by quantum field theorists since the developments in particle physics and inflationary scenarios . according to modern quantum field theory.
Please generate the next two sentences of the article | , the structure of a vacuum turns out to be interrelated with some spontaneous symmetry - breaking effects through the condensation of quantum ( scalar ) fields .
this phenomenon gives rise to a non - vanishing vacuum energy density of the form @xmath9 . |
9,676 | Suppose that you have an abstract for a scientific paper: we present a new class of black hole solutions with a minimally coupled scalar field in the presence of a negative cosmological constant .
we consider an one - parameter family of self - interaction potentials parametrized by a dimensionless parameter @xmath0 .
when @xmath1 , we recover the conformally invariant solution of the martinez - troncoso - zanelli ( mtz ) black hole .
a non - vanishing @xmath0 signals the departure from conformal invariance .
thermodynamically , there is a critical temperature at vanishing black hole mass , where a higher - order phase transition occurs , as in the case of the mtz black hole .
additionally , we obtain a branch of hairy solutions which undergo a first - order phase transition at a second critical temperature which depends on @xmath0 and it is higher than the mtz critical temperature . as @xmath2 ,
this second critical temperature diverges .
+ * theodoros kolyvaris @xmath3 * , * george koutsoumbas @xmath4 * , + * eleftherios papantonopoulos @xmath5 * + department of physics , national technical university of athens , + zografou campus gr 157 73 , athens , greece + department of physics and astronomy , the university of tennessee , + knoxville , tn 37996 - 1200 , usa + @xmath6 e - mail address : [email protected] + @xmath7 e - mail address : [email protected] + @xmath8 e - mail address : [email protected] + @xmath9 e - mail address : [email protected] .
And you have already written the first three sentences of the full article: four - dimensional black hole solutions of einstein gravity coupled to a scalar field have been an avenue of intense research for many years .
questions pertaining to their existence , uniqueness and stability were seeking answers over these years .
the kerr - newman solutions of four - dimensional asymptotically flat black holes coupled to an electromagnetic field or in vacuum , imposed very stringent conditions on their existence in the form of no - hair " theorems . in the case of a minimally coupled scalar field in asymptotically flat spacetime.
Please generate the next two sentences of the article | the no - hair theorems were proven imposing conditions on the form of the self - interaction potential @xcite .
these theorems were also generalized to non - minimally coupled scalar fields @xcite . for asymptotically flat spacetime , a four - dimensional black hole coupled to a scalar field with a zero self - interaction potential |
9,677 | Suppose that you have an abstract for a scientific paper: we present results from an analytic calculation of thermal meson spectral functions in the infinite temperature ( free field ) limit .
we compare spectral functions for various lattice fermion formulations used at present in studies of in - medium properties of hadrons based on the maximum entropy method ( mem ) .
in particular , we will present a new calculation of spectral functions performed with extended quark sources .
bi - tp 2003/28 + bnl - nt-03/29 .
And you have already written the first three sentences of the full article: the modification of in - medium properties of mesons is one of the crucial concepts explored in experimental studies of hot and dense matter in created in heavy ion collisions .
it is the hope that the creation of a dense matter and eventually also the quark gluon plasma can be unambiguously demonstrated through the study of modifications generated in the spectrum of heavy ( @xmath0-suppression ) as well as light quark bound states ( shift of the @xmath1-meson mass , resonance broadening , thermal dilepton enhancement , .. ) .
lattice calculations can contribute to the theoretical discussion of these burning experimental questions through the calculation of thermal spectral functions , which control the structure of hadron correlation functions at finite temperature ..
Please generate the next two sentences of the article | the reconstruction of spectral functions from hadron correlation functions calculated on the lattice at finite temperature is based on a statistical tool , the maximum entropy method ( mem ) @xcite which has been explored and tested over recent years .
we will discuss here results of an analytic calculation , which becomes feasible in the infinite temperature limit which corresponds to a free fermion theory . |
9,678 | Suppose that you have an abstract for a scientific paper: this work presents a reduced @xmath0 test to search for non - gaussian signals in the cmbr tt power spectrum of recent cmbr data , wmap , acbar and cbi data sets , assuming a mixed density field including adiabatic and isocurvature fluctuations .
we assume a skew positive mixed model with adiabatic inflation perturbations plus additional isocurvature perturbations possibly produced by topological defects .
the joint probability distribution used in this context is a weighted combination of gaussian and non - gaussian random fields .
results from simulations of cmbr temperature for the mixed field show a distinct signature in cmb power spectrum for very small deviations ( @xmath1 0.1% ) from a pure gaussian field , and can be used as a direct test for the nature of primordial fluctuations .
a reduced @xmath0 test applied on the most recent cmbr observations reveals that an isocurvature fluctuations field is not ruled out and indeed permits a very good description for a flat geometry @xmath2-cdm universe , @xmath3@xmath1 1.5 , rather than the simple inflationary standard model with @xmath3@xmath1 2.3 .
this result may looks is particular discrepant with the reduced @xmath4 of 1.07 obtained with the same model in spergel et al .
( 2003 ) for temperature only , however , our work is restricted to a region of the parameter space that does not include the best fit model for tt only of spergel et al .
( 2003 ) . .
And you have already written the first three sentences of the full article: the new generation of cosmic microwave background radiation ( cmbr ) experiments has opened a new era in astrophysics , the precision cosmology era .
recent observations , especially those of wmap ( wilkinson anisotropy microwave probe ) , acbar ( arcminute cosmology bolometer array receiver ) and cbi ( cosmic background imager ) , brought a new light to cmbr fluctuations studies in large , intermediate and small scales .
this new generation of experiments made possible the characterization of the power spectrum of temperature fluctuations up to the third acoustic peak ( hinshwaw et al . 2003.
Please generate the next two sentences of the article | ; pearson et al . 2002 ; kuo et al . 2004 ) . indeed , the combination of cmbr and large scale structure ( lss ) data allows cosmologists to constrain cosmological parameters for a given set of scenarios and also determine the nature of the primordial fluctuations . since cmbr carries the intrinsic statistical properties of cosmological perturbations , it is considered the most powerful tool to investigate the nature of cosmic structure . the most accepted model for structure formation assumes initial quantum fluctuations created during inflation and amplified by gravitational effects .
the standard inflation model predicts an adiabatic uncorrelated random field with a nearly flat , scale - invariant spectrum on scales larger than @xmath1 1 - 2@xmath5 ( guth 1981 ; salopek , bond & bardeen 1981 ; bardeen , steinhardt & turner 1983 ) . |
9,679 | Suppose that you have an abstract for a scientific paper: we combine newly measured rotation velocities , velocity dispersions , and stellar masses to construct stellar mass tully - fisher relations ( m@xmath0tfrs ) for 544 galaxies with strong emission lines at @xmath1 from the all wavelength extended groth strip international survey ( aegis ) and the deep extragalactic evolutionary probe 2 survey ( deep2 ) .
the conventional m@xmath0tfr using only rotation velocity ( @xmath2 ) shows large scatter ( @xmath3 dex in velocity ) .
the scatter and residuals are correlated with morphology in the sense that disturbed , compact , and major merger galaxies have lower velocities for their masses .
we construct an m@xmath0tfr using the kinematic estimator @xmath4 which is defined as @xmath5 and accounts for disordered or non - circular motions through the gas velocity dispersion ( @xmath6 ) .
the new m@xmath0tfr , termed @xmath4/m@xmath0tfr , is remarkably tight over @xmath1 with no detectable evolution of its intercept or slope with redshift .
the average best fit relation has 0.47 dex scatter in stellar mass , corresponding to @xmath7 ` magnitudes , ' assuming a constant mass - to - light ratio .
interestingly , the @xmath4/m@xmath0tfr is consistent with the absorption - line based stellar mass faber - jackson relation for nearby elliptical galaxies in terms of slope and intercept , which might suggest a physical connection between the two relations . .
And you have already written the first three sentences of the full article: the tully - fisher relation ( tfr ) between the luminosity of galaxies and their rotation velocity is a fundamental scaling relation that constrains galaxy formation and evolution models ( e.g. , * ? ? ? * and references therein ) .
recent local studies focus on stellar or baryonic masses ( e.g. , * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ) , which are easier to model than luminosity . |
9,680 | Suppose that you have an abstract for a scientific paper: interactions between a protein and a ligand are often accompanied by a redistribution of the population of thermally accessible conformations .
this dynamic response of the protein s functional energy landscape enables a protein to modulate binding affinities and control binding sensitivity to ligand concentration . in this paper , we investigate the structural origins of binding affinity and allosteric cooperativity of binding two ca@xmath0ions to each domain of calmodulin ( cam ) through simulations of a simple coarse - grained model . in this model ,
the protein s conformational transitions between open and closed conformational ensembles are simulated explicitly and ligand binding and unbinding is treated implicitly within the grand canonical ensemble .
ligand binding is cooperative because the binding sites are coupled through a shift in the dominant conformational ensemble upon binding .
the classic monod - wyman - changeux model of allostery with appropriate binding free energy to the open and closed ensembles accurately describes the simulated binding thermodynamics .
the simulations predict that the two domains of cam have distinct binding affinity and cooperativity .
in particular , c - terminal domain binds ca@xmath0with higher affinity and greater cooperativity than the n - terminal domain . from a structural point of view , the affinity of an individual binding loop depends sensitively on the loop s structural compatibility with the ligand in the bound ensemble , as well as the conformational flexibility of the binding site in the unbound ensemble . .
And you have already written the first three sentences of the full article: conformational dynamics is essential for a protein s ability to exhibit allostery .
the coupling between two distant binding sites is frequently accomplished by a conformational change between a `` closed '' ( apo ) to an `` open '' ( holo ) conformation upon ligation.@xcite although the end point conformations often give valuable insight into protein function , a detailed description of the allosteric mechanism for a particular protein requires one to consider a broader conformational ensemble .
the landscape theory of binding@xcite acknowledges that a folded protein is inherently dynamic and explores the thermally accessible conformational states in its native basin.@xcite this conformational ensemble comprises the protein s `` functional landscape''.@xcite while only a small subset of the states comprising the folding energy landscape@xcite , the functional landscape determines how a protein responds to the changes in its local environment such as ligand interactions . due to the heterogeneous nature of the conformational ensemble ,.
Please generate the next two sentences of the article | a ligand preferentially stabilizes some conformations more than others , causing the protein s thermal population to redistribute to a ligated ensemble which in general has distinct equilibrium properties.@xcite the ensemble nature of allostery accommodates a rich and diverse set of regulatory strategies and provides a general framework to understand binding thermodynamics and kinetics of specific proteins.@xcite even simple landscapes with a small number of well defined basins separated by kinetic barriers can have subtle binding mechanisms because they depend on ligand interactions to short - lived transient states .
experimental progress on this challenging kinetics problem has appeared only very recently.@xcite in principle , affinities of metastable states can also be obtained from thermodynamic binding measurements , although such analysis may not always be practical . in this paper |
9,681 | Suppose that you have an abstract for a scientific paper: wireless sensor networks ( wsns ) consist of numerous sensors which send sensed data to base station .
energy conservation is an important issue for sensor nodes as they have limited power .
many routing protocols have been proposed earlier for energy efficiency of both homogeneous and heterogeneous environments .
we can prolong our stability and network lifetime by reducing our energy consumption . in this research paper
, we propose a protocol designed for the characteristics of a reactive homogeneous wsns , heer ( hybrid energy efficient reactive ) protocol . in heer
, cluster head(ch ) selection is based on the ratio of residual energy of node and average energy of network .
moreover , to conserve more energy , we introduce hard threshold ( ht ) and soft threshold ( st ) .
finally , simulations show that our protocol has not only prolonged the network lifetime but also significantly increased stability period .
wireless , sensor , networks , energy , hybrid , cluster , reactive .
And you have already written the first three sentences of the full article: et al_. [ 1 ] , introduced the first hierarchical clustering algorithm for wsns , called leach .
it is one of the most popular protocols in wsns .
the main idea is to form clusters of the sensor nodes ..
Please generate the next two sentences of the article | leach outperforms classical clustering algorithm by using adaptive clustering and rotating chs .
this saves energy as transmission will only be performed on that specific ch rather than all the nodes . |
9,682 | Suppose that you have an abstract for a scientific paper: we report the discovery of a probable large scale structure composed of many galaxy clumps around the known twin clusters at @xmath0 and @xmath1 in the lynx region .
our analysis is based on deep , panoramic , and multi - colour imaging ( 26.4@[email protected]@xmath2 ) in @xmath4-bands with the suprime - cam on the 8.2 m subaru telescope .
this unique , deep and wide - field imaging data - set allows us for the first time to map out the galaxy distribution in the highest redshift supercluster known .
we apply a photometric redshift technique to extract plausible cluster members at @xmath5 down to @xmath6=26.15 ( 5@xmath7 ) corresponding to @xmath8 at this redshift . from the 2-d distribution of these photometrically selected galaxies , we newly identify seven candidates of galaxy groups or clusters where the surface density of red galaxies is significantly high ( @xmath95@xmath7 ) , in addition to the two known clusters .
these candidates show clear red colour - magnitude sequences consistent with a passive evolution model , which suggests the existence of additional high density regions around the lynx superclusters .
[ firstpage ] galaxies : clusters : individual ( rxj 0848.6 + 4453 , rxj 0848.9 + 4452 ) galaxies : evolution galaxies : formation cosmology : large - scale structure of universe .
And you have already written the first three sentences of the full article: superclusters are the largest systems of galaxies , composed of multiple clusters of galaxies , extending over 10 - 20 mpc ( e.g. , bahcall , soneira 1984 ; postman , geller , huchra 1988 ; quintana et al
. 1995 ; small et al . 1998 ) .
according to the n - body simulations which successfully reproduce the observed filamentary structures at the local universe ( e.g. , peacock et al ..
Please generate the next two sentences of the article | 2001 ) , clusters of galaxies at @xmath10 are still in the process of formation ( e.g. , moore et al .
therefore , clusters of galaxies at this cosmological distance , especially superclusters , are important sites where we can directly see the process of structure formation and evolution and mass assembly to cluster cores . despite the importance in the cosmological context |
9,683 | Suppose that you have an abstract for a scientific paper: although dust content is usually assumed to depend uniquely on metallicity , recent observations of two extremely metal - poor dwarf galaxies have suggested that this may not always be true . at a similar oxygen abundance of @xmath03%@xmath1 , the dust - to - gas and dust - to - stellar mass ratios in sbs0335@xmath2052 and izw18differ by a factor 40 - 70 according to including molecular gas or excluding it . here
we investigate a possible reason for this dramatic difference through models based on a semi - analytical formulation of chemical evolution including dust .
results suggest that the greater dust mass in sbs0335@xmath2052 is due to the more efficient grain growth allowed by the high density in the cold interstellar medium ( ism ) , observationally inferred to be almost 20 times higher than in izw18 .
our models are able to explain the difference in dust masses , suggesting that efficient dust formation and dust content in galaxies , including those with the highest measured redshifts , depend sensitively on the ism density , rather than only on metallicity .
[ firstpage ] ism : abundances ism : evolution galaxies : starburst galaxies : dwarf galaxies : evolution galaxies : individual : sbs0335 - 052 galaxies : individual : izw18 .
And you have already written the first three sentences of the full article: the dust content in galaxies is intimately linked to their evolutionary history
. nevertheless , the mass of the dust in the interstellar medium ( ism ) , and its ratio with the gas mass ( dust - to - gas ratio , dgr ) , are critical parameters for establishing the evolutionary state of a galaxy .
however , the complex interplay between dust destruction and dust formation mechanisms ( e.g. , * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ; * ? ? ? |
9,684 | Suppose that you have an abstract for a scientific paper: we explore the effects of different boundary conditions and coupling schemes on the response of a particle detector undergoing uniform acceleration in optical cavities .
we analyze the thermalization properties of the accelerated detector via non - perturbative calculations .
we prove non - perturbatively that if the switching process is smooth enough , the detector thermalizes to the unruh temperature regardless of the boundary conditions and the form of the coupling considered . .
And you have already written the first three sentences of the full article: the interaction between matter and the gravitational field has evaded a complete quantum description since the first attempts to formulate a quantum theory of gravity more than 60 years ago .
lacking a satisfactory quantum description of the gravitational interaction , quantum field theory in curved spacetimes ( which links general relativity with quantum field theory ) is thus far the most satisfactory framework to describe the interaction of quantum fields with the space - time curvature . as of today
none of its predictions has been experimentally confirmed beyond analogue gravity @xcite , and bringing those effects within experimental reach is a matter of great interest @xcite ..
Please generate the next two sentences of the article | one of the chief predictions of quantum field theory ( qft ) in curved spacetimes is the well - known unruh effect @xcite .
it dictates that a detector with constant acceleration @xmath0 in free space , in which the field is in the minkowski vacuum , will experience a response equivalent to its submersion into a heat bath with a temperature proportional to its acceleration . |
9,685 | Suppose that you have an abstract for a scientific paper: low multipole amplitudes in the cosmic microwave background cmb radiation can be explained by selection rules from the underlying multiply - connected homotopy .
we apply a multipole analysis to the harmonic bases and introduce point symmetry .
we give explicit results for two cubic 3-spherical manifolds and lowest polynomial degrees , and derive three new spherical 3-manifolds .
address = institut fr theoretische physik der universitt tbingen , + germany .
And you have already written the first three sentences of the full article: cosmology deals with the large - scale structure of the universe .
a global description of this structure employs an averaging and smoothing of all the objects of astrophysics from solar systems to galaxies and clusters of galaxies .
the result is a fluid model of the cosmos goverened by gravitation , as it was proposed by einstein @xcite , see @xcite pp ..
Please generate the next two sentences of the article | 160 - 164 and @xcite pp .
704 - 710 . |
9,686 | Suppose that you have an abstract for a scientific paper: we study a class of holomorphic matrix models .
the integrals are taken over middle dimensional cycles in the space of complex square matrices . as the size of the matrices tends to infinity
, the distribution of eigenvalues is given by a measure with support on a collection of arcs in the complex planes .
we show that the arcs are level sets of the imaginary part of a hyperelliptic integral connecting branch points .
_ department of mathematics , eth zurich _ _ 8092 zurich , switzerland _ .
And you have already written the first three sentences of the full article: according to dijkgraaf and vafa @xcite , the effective glueball superpotential of @xmath0 supersymmetric @xmath1 gauge theory has an asymptotic expansion given by the planar part of the topological expansion of a matrix model . to give the effective potential for various vacua of the gauge theory , dijkgraaf and vafa
propose a formula obtained by saddle point expansion of the matrix integral around different critical points .
the filling fractions , i.e. , the fraction of the eigenvalues sitting close to each of the critical points of the potential are the parameters selecting the vacua . in this paper we give a way to define non - perturbatively ( i.e. , beyond the saddle point expansion ) the matrix integrals ..
Please generate the next two sentences of the article | different integrals are integrals over different cycles in the space of normal matrices . in the case of generic polynomial potentials
it is possible to construct a cycle for each of the critical points , so that all effective potentials considered by dijkgraaf and vafa arise in the asymptotic expansion of our integrals . |
9,687 | Suppose that you have an abstract for a scientific paper: the alpha magnetic spectrometer ( ams ) to be installed on the international space station ( iss ) will measure charged cosmic ray spectra of elements up to iron , in the rigidity range from 1gv to 1tv , for at least three years .
ams is a large angular spectrometer composed of different subdetectors , including a proximity focusing ring imaging cherenkov ( rich ) detector .
this will be equipped with a mixed radiator made of aerogel and sodium fluoride ( naf ) , a lateral conical mirror and a detection plane made of 680 photomultipliers coupled to light guides .
the rich detector allows measurements of particle s electric charge up to iron , and particle s velocity .
two possible methods for reconstructing the erenkov angle and the electric charge with the rich will be discussed . a rich prototype consisting of a detection matrix with 96 photomultipliers , a segment of a conical mirror and samples of the radiator materials was built and its performance was evaluated using ion beam data .
results from the last test beam performed with ion fragments resulting from the collision of a 158gev / c / nucleon primary beam of indium ions ( cern sps ) on a lead target are reported . the large amount of collected data allowed to test and characterize different aerogel samples and the naf radiator .
in addition , the reflectivity of the mirror was evaluated .
the data analysis confirms the design goals . .
And you have already written the first three sentences of the full article: the alpha magnetic spectrometer @xcite ( ams ) is a particle detector to be installed in the international space station ( iss ) for at least three years .
the spectrometer will be able to measure the rigidity ( @xmath0 ) , the charge ( @xmath1 ) , the velocity ( @xmath2 ) and the energy ( @xmath3 ) of cosmic rays from some mev up to @xmath41tev within a geometrical acceptance of @[email protected] .
shows a schematic view of the ams spectrometer . at both ends of the ams spectrometer.
Please generate the next two sentences of the article | exist the transition radiation detector ( trd ) ( top ) and the electromagnetic calorimeter ( ecal ) ( bottom ) .
both will provide ams with capability to discriminate between leptons and hadrons . additionally the calorimeter will trigger and detect photons . |
9,688 | Suppose that you have an abstract for a scientific paper: it was recently proposed that metal - rich white dwarfs ( wds ) accrete their metals from compact debris disks found to exist around more than a dozen of them . at the same time , elemental abundances measured in atmospheres of some wds imply vigorous metal accretion at rates up to @xmath0 g s@xmath1 , far in excess of what can be supplied solely by poynting - robertson drag acting on such debris disks .
to explain this observation we propose a model , in which rapid transport of metals from the disk onto the wd naturally results from interaction between this particulate disk and spatially coexisting disk of metallic gas .
the latter is fed by evaporation of debris particles at the sublimation radius located at several tens of wd radii . because of pressure support gaseous disk orbits wd slower than particulate disk .
resultant azimuthal drift between them at speed @xmath2 m s@xmath1 causes aerodynamic drag on the disk of solids and drives inward migration of its constituent particles . upon reaching the sublimation radius particles evaporate , enhancing the density of metallic gaseous disk and leading to positive feedback . under favorable circumstances ( low viscosity in the disk of metallic gas and efficient aerodynamic coupling between the disks )
system evolves in a runaway fashion , destroying debris disk on time scale of @xmath3 yr , and giving rise to high metal accretion rates up to @xmath4 g s@xmath1 , in agreement with observations . .
And you have already written the first three sentences of the full article: recent detections of near - infrared excesses around a number of metal - rich white dwarfs ( wd ) imply existence of warm circumstellar material reprocessing stellar radiation ( zuckerman & becklin 1987 ; graham 1990 ; farihi 2010 ) .
spectral modeling suggests that this material resides in an extended , compact , optically thick and geometrically thin disk ( jura 2003 ; jura 2007 ) , similar to the saturn s rings ( cuzzi 2010 ) .
disks have inner edges at several tens of the wd radii @xmath5 , roughly consistent with being set by particle sublimation at these locations ..
Please generate the next two sentences of the article | their outer radii lie close to the roche radius of the wd @xmath6 r@xmath7 , supporting the suggestion by jura ( 2003 ) that such compact debris disks are produced by tidal disruption of asteroid - like bodies scattered into low - periastron orbits by gravitational perturbations of massive planets , which have survived the agb phase of stellar evolution .
availability of large reservoir of high - z elements in the form of debris disk in the immediate vicinity of some wds naturally led to the suggestion ( jura 2003 ) that metal enrichment of these stars is caused by accretion from such disks . |
9,689 | Suppose that you have an abstract for a scientific paper: using the recently developed bloch - state tomography technique , the quasimomentum @xmath0-dependent bloch states @xmath1 of a two - band tight - binding model with two sublattices can be mapped out .
we show that , if we prepare the initial bloch state as the lower - band eigenstate of a topologically trivial haldane hamiltonian @xmath2 , and then quench the haldane hamiltonian to @xmath3 , the time - dependent azimuthal phase @xmath4 supports two types of vortices .
the first type of vortices are static , with the corresponding bloch vectors pointing to the north pole ( @xmath5 ) .
the second type of vortices are dynamical , with the corresponding bloch vectors pointing to the south pole ( @xmath6 ) . in the @xmath7 space ,
the linking number between the trajectories of these two types of vortices equals exactly to the chern number of the lower band of @xmath3 , which provides an alternative method to directly map out the topological phase boundaries of the haldane model . .
And you have already written the first three sentences of the full article: topological insulators have attracted a lot of interests due to their novel properties and potential applications @xcite .
one of the prototype of topological insulators is the haldane model of chern insulators @xcite , which describes spinless fermions hopping on a 2d honeycomb lattice , within a staggered magnetic field . with the shaking - lattice technique @xcite , the haldane model has been realized directly in a recent cold atom experiment @xcite , and the topological phase diagram is investigated using the bloch oscillation method .
it is worth mentioning that , although the haldane model is realized in the cold atom setup , the topological ground state for this system is generally hard , if not impossible , to be reached ..
Please generate the next two sentences of the article | as the system is generally prepared in a topologically trivial state before the shaking is applied , by driving the system crossing the phase boundary to the topological phase , excitations are inevitable as the band gap closes at the phase boundary and adiabaticity could not be maintained .
the idea of a quantum quench , which starts with the ground state of a topologically trivial hamiltonian @xmath2 supplemented by the evolution of a topologically trivial / nontrivial hamiltonian @xmath3 , provides an alterative way to studying the properties of the haldane model ( and haldane - like topological models ) @xcite . |
9,690 | Suppose that you have an abstract for a scientific paper: the quark - gluon plasma ( qgp ) is the qcd phase of matter expected to be formed at small proper - times in the collision of heavy - ions at high energy .
experimental observations seem to favor a strongly coupled qcd plasma with the hydrodynamic properties of a quasi - perfect fluid , _ i.e. _ @xmath0 rapid thermalization ( or isotropization ) and small viscosity .
the theoretical investigation of such properties is not obvious , due to the the strong coupling .
the gauge / gravity correspondence provides a stimulating framework to explore the strong coupling regime of gauge theories using the dual string description .
after a brief introduction to gauge / gravity duality , and among various existing studies , we focus on challenging problems of qgp hydrodynamics , such as viscosity and thermalization , in terms of gravitational duals of both the static and relativistically evolving plasma .
we show how a black hole geometry arises naturally from the dual properties of a nearly perfect fluid and explore the lessons and prospects one may draw for actual heavy ion collisions from the gauge / gravity duality approach . .
And you have already written the first three sentences of the full article: the formation of a qgp ( quark gluon plasma ) is expected to be realized in high - energy heavy - ion collisons , _
e.g. _ at rhic and soon at the lhc .
one of the main tools for the description of such a formation is the relevance of relativistic hydrodynamic equations in some intermediate stage of the collisons , see fig.[qgp ] ..
Please generate the next two sentences of the article | [ hb ] the problem of the hydrodynamic description is the uneasiness of the relation with the underlying fundamental theory .
indeed , the experimental observations seem to indicate an almost perfect - fluid behaviour with small shear viscosity , which naturally leads to consider a theory at strong coupling and thus within the yet unknown nonperturbative regime of qcd |
9,691 | Suppose that you have an abstract for a scientific paper: a numerical analysis of a one - dimensional hamiltonian system , composed by @xmath0 classical localized heisenberg rotators on a ring , is presented .
a distance @xmath1 between rotators at sites @xmath2 and @xmath3 is introduced , such that the corresponding two - body interaction decays with @xmath1 as a power - law , @xmath4 ( @xmath5 ) .
the index @xmath6 controls the range of the interactions , in such a way that one recovers both the fully - coupled ( i.e. , mean - field limit ) and nearest - neighbour - interaction models in the particular limits @xmath7 and @xmath8 , respectively .
the dynamics of the model is investigated for energies @xmath9 below its critical value ( @xmath10 ) , with initial conditions corresponding to zero magnetization .
the presence of quasi - stationary states ( qsss ) , whose durations @xmath11 increase for increasing values of @xmath0 , is verified for values of @xmath6 in the range @xmath12 , like the ones found for the similar model of xy rotators .
moreover , for a given energy @xmath9 , our numerical analysis indicates that @xmath13 , where the exponent @xmath14 decreases for increasing @xmath6 in the range @xmath12 , and particularly , our results suggest that @xmath15 as @xmath16 .
the growth of @xmath11 with @xmath0 could be interpreted as a breakdown of ergodicity , which is shown herein to occur for any value of @xmath6 in this interval . .
And you have already written the first three sentences of the full article: classical spin models have called the attention of statistical - mechanics and magnetism researchers throughout many years @xcite .
many techniques have been used in their study , both analytical and numerical , in such a way that a reasonable knowledge of their equilibrium thermodynamics has been achieved , and specially , of their critical properties . among those models
, one could mention the classical spin models , which present the xy ( @xmath17 ) and heisenberg ( @xmath18 ) as particular cases ..
Please generate the next two sentences of the article | an interesting formulation of a @xmath19-vector classical model comes when one adds a kinetic term to its hamiltonian , i.e. , the spin variables may be interpreted as classical rotators ( see , e.g. , refs .
@xcite ) , so that the terminology `` inertial model '' is currently used . |
9,692 | Suppose that you have an abstract for a scientific paper: this letter considers the problem of signal denoising using a sparse tight - frame analysis prior .
the @xmath0 norm has been extensively used as a regularizer to promote sparsity ; however , it tends to under - estimate non - zero values of the underlying signal .
to more accurately estimate non - zero values , we propose the use of a non - convex regularizer , chosen so as to ensure convexity of the objective function .
the convexity of the objective function is ensured by constraining the parameter of the non - convex penalty .
we use admm to obtain a solution and show how to guarantee that admm converges to the global optimum of the objective function .
we illustrate the proposed method for 1d and 2d signal denoising . .
And you have already written the first three sentences of the full article: standard technique for estimating sparse signals is through the formulation of an inverse problem with the @xmath0 norm as convex proxy for sparsity . in particular , consider the problem of estimating a signal @xmath1 from a noisy observation @xmath2 , @xmath3where @xmath4 represents awgn .
we assume the underlying signal to be sparse with respect to an overcomplete tight frame @xmath5 , @xmath6 , which satisfies the tight frame condition , i.e. , @xmath7using an analysis - prior , we formulate the signal denoising problem as @xmath8_i ; a_i \right)\biggr\rbrace,\end{aligned}\ ] ] where @xmath9 are the regularization parameters , and @xmath10 is a non - smooth sparsity inducing penalty function .
the parameters @xmath11 control the non - convexity of @xmath12 in case it is non - convex ..
Please generate the next two sentences of the article | the analysis prior is used in image processing and computer vision applications @xcite .
commonly , the @xmath0 norm is used to induce sparsity , i.e. , @xmath13 @xcite . in that case , problem is strictly convex and the global optimum can be reliably obtained . |
9,693 | Suppose that you have an abstract for a scientific paper: we revisit the theory of tunnel - coupled atomic quasicondensates in double - well elongated traps at finite temperatures . using the functional integral approach , we calculate the relative phase correlation function beyond the harmonic limit of small fluctuations of the relative phase and its conjugate relative - density variable .
we show that the thermal fluctuations of the relative phase between the two quasicondensates decrease the frequency of josephson oscillations and even wash out these oscillations for small values of the tunnel coupling . .
And you have already written the first three sentences of the full article: systems of ultracold bosonic atoms in two parallel atomic waveguides mutually coupled via quantum tunneling ( so - called extended bosonic josephson junctions ) have been a subject of intensive theoretical @xcite and experimental @xcite studies .
the finite spatial extension of these systems provides much richer physics compared to the case of a point - like bosonic josephson junction @xcite .
the novel features arise due to the enhanced role of noise and correlations in low - dimensional ultracold atomic systems . before discussing the effects of tunneling ,.
Please generate the next two sentences of the article | we recall the basic properties of a bosonic system in an isolated waveguide @xcite .
this system is effectively one - dimensional ( 1d ) , if the interaction energy per atom ( we assume interatomic repulsion characterized by the effective 1d coupling strength @xmath0 ) and the temperature are well below the spacing between the discrete energy levels of the potential of tight radial confinement . in this case |
9,694 | Suppose that you have an abstract for a scientific paper: we aim to understand the role of coulomb interactions as well as of different equations of state on the disappearance of transverse flow for various asymmetric reactions leading to same total mass . for the present study ,
the total mass of the system is kept constant ( @xmath0 = 152 ) and asymmetry of the reaction is varied between 0.2 and 0.7 .
we find that the contribution of mean - field at low incident energies is more for nearly symmetric systems , while the trend is opposite at higher incident energies .
the coulomb interactions as well as different equations of state are found to affect the balance energy significantly for larger asymmetric reactions . .
And you have already written the first three sentences of the full article: the heavy - ion physics has attracted much attention during the last three decades @xcite . the behavior of nuclear matter under the extreme conditions of temperature , density , angular momentum etc .
, is a very important aspect of heavy - ion physics .
one of the important quantity which has been used extensively to study this hot and dense nuclear matter is the collective transverse in - plane flow @xcite ..
Please generate the next two sentences of the article | this quantity has a beauty of vanishing at a certain incident energy .
this energy is dubbed as balance energy ( @xmath1 ) or the energy of vanishing flow ( evf ) @xcite . |
9,695 | Suppose that you have an abstract for a scientific paper: evidence of signatures associated with cryptographic modes of operation is established . motivated by some analogies between cryptographic and dynamical systems ,
in particular with chaos theory , we propose an algorithm based on lyapunov exponents of discrete dynamical systems to estimate the divergence among ciphertexts as the encryption algorithm is applied iteratively .
the results allow to distinguish among six modes of operation , namely ecb , cbc , ofb , cfb , ctr and pcbc using des , idea , tea and xtea block ciphers of 64 bits , as well as aes , rc6 , twofish , seed , serpent and camellia block ciphers of 128 bits .
furthermore , the proposed methodology enables a classification of modes of operation of cryptographic systems according to their strength . .
And you have already written the first three sentences of the full article: the propagation and continuous flow of information are of utter importance for the development of stable economies throughout the world as they are a prerequisite for successful business transactions , short- and long - range communication , and so on @xcite .
often this information has to be encrypted in such a way that it can be safely transferred between the sender and recipient without allowing others to read the information that is present in such an encrypted message @xcite . on the other hand ,
malicious persons and organizations , but also governmental organizations , are continuously striving to break the key with which messages were encrypted because this might enable them to get those pieces of information that are needed to achieve their criminal , protective , or other goals @xcite ..
Please generate the next two sentences of the article | it is probably due to the impact of turing s success in breaking the enigma that humanity became aware of the importance of cryptography in general , and the vulnerability of ciphers more in particular @xcite . since this major breakthrough , the functioning of the industrial , financial and public sector has become strongly dependent on the advances of cryptography .
for instance , while the availability of worldwide networks has enabled rapid dissemination of information , it has also stimulated cryptographic innovations because a significant share of this information may only be available to a few parties . in this manner , technological progress during the last decades has increased the need for secured communication and transactions , information shielding , and so on @xcite . in the last few decades , modern cryptography replaced mechanical schemes with new computing models . |
9,696 | Suppose that you have an abstract for a scientific paper: we prove that every countable acylindrically hyperbolic group admits a highly transitive action with finite kernel .
this theorem uniformly generalizes many previously known results and allows us to answer a question of garion and glassner on the existence of highly transitive faithful actions of mapping class groups .
it also implies that in various geometric and algebraic settings , the transitivity degree of an infinite group can only take two values , namely @xmath0 and @xmath1 . here by _
transitivity degree _ of a group we mean the supremum of transitivity degrees of its faithful permutation representations .
further , for any countable group @xmath2 admitting a highly transitive faithful action , we prove the following dichotomy : either @xmath2 contains a normal subgroup isomorphic to the infinite alternating group or @xmath2 resembles a free product from the model theoretic point of view .
we apply this theorem to obtain new results about universal theory and mixed identities of acylindrically hyperbolic groups .
finally , we discuss some open problems . .
And you have already written the first three sentences of the full article: recall that an action of a group @xmath2 on a set @xmath3 is _
@xmath4-transitive _ if @xmath5 and for any two @xmath4-tuples of distinct elements of @xmath3 , @xmath6 and @xmath7 , there exists @xmath8 such that @xmath9 for @xmath10 .
the _ transitivity degree _ of a countable group @xmath2 , denoted @xmath11 , is the supremum of all @xmath12 such that @xmath2 admits a @xmath4-transitive faithful action . for finite groups ,.
Please generate the next two sentences of the article | this notion is classical and fairly well understood .
it is easy to see that @xmath13 , @xmath14 , and it is a consequence of the classification of finite simple groups that any finite group @xmath2 other than @xmath15 or @xmath16 has @xmath17 . |
9,697 | Suppose that you have an abstract for a scientific paper: we present comprehensive cluster membership and @xmath0 photometry of the prototypical old , metal - rich galactic star cluster ngc 6791 .
the proper - motion catalog contains 58,901 objects down to @xmath124 , limited to a circular area of radius 30@xmath2 .
the highest precision of the proper motions is 0.08 mas yr@xmath3 .
our proper motions confirm cluster membership of all main and also some rare constituents of ngc 6791 .
the total number of probable cluster members down to @xmath4 ( @xmath58 ) is @xmath64800 , corresponding to @xmath7 .
new findings include an extended horizontal branch in this cluster .
the angular radius of ngc 6791 is at least 15@xmath2 ( the effective radius is @xmath8 while the tidal radius is @xmath9 ) .
the luminosity function of the cluster peaks at @xmath104.5 and then steadily declines toward fainter magnitudes .
our data provide evidence that differential reddening may not be ignored in ngc 6791 . .
And you have already written the first three sentences of the full article: ngc 6791 is an extreme galactic star cluster with an old age of @xmath68 gyr @xcite , a high metallicity [ fe / h][email protected] @xcite , and an unusual orbit that periodically brings it close to the bulge of the milky way @xcite .
@xcite was the first to provide an estimate for the total mass of ngc 6791 : @xmath63700@xmath12 down to @xmath1320 , confirmed by @xcite .
it is widely acknowledged that ngc 6791 is one of the most massive old open clusters in our galaxy . as indicated by the discovery of several extremely blue subdwarfs @xcite and the presence of a prominent red clump , morphology of the color - magnitude diagram ( cmd ) for ngc 6791 is complex ..
Please generate the next two sentences of the article | the proposed enhanced mass loss along the red giant branch ( rgb ) appears to explain the presence of hot subdwarfs and the abnormally young 2.4 gyr white dwarf cooling age @xcite .
recently , @xcite reported that the cmd in the inner part of ngc 6791 ( @xmath14 ) is somewhat different from that in its outer part ( @xmath15 ) . |
9,698 | Suppose that you have an abstract for a scientific paper: a scheme with gold cone - capillary is proposed to improve the protons acceleration and involved problems are investigated by using the two - dimensional particle - in - cell simulations .
it is demonstrated that the cone - capillary can efficiently guide and collimate the protons to a longer distance and lead to a better beam quality with a dense density @xmath0 , monoenergetic peak energy @xmath1 , spatial emittance @xmath2 with divergence angle @xmath3 and diameter @xmath4 .
the enhancement is mainly attributed to the focusing effect by the transverse electric field generated by the cone as well as the capillary , which can prevent greatly the protons from expanding in the transverse direction .
comparable to without the capillary , the protons energy spectra have a stable monoenergetic peak and divergence angle near to @xmath5 in longer time .
besides , the efficiency of acceleration depending on the capillary length is explored , and the optimal capillary length is also achieved . such a target may be benefit to many applications such as ions fast ignition in inertial fusion , proton therapy in medicine and so on . .
And you have already written the first three sentences of the full article: with the wide application , the charged particles acceleration based on the laser - plasma interaction have been rapidly concerned by many simulations and experiments @xcite . in recent years , the proton acceleration generated by an ultraintense laser irradiating a solid target has been investigated extensively due to the potential applications in ions fast ignition ( fi ) of inertial confinement fusion ( icf ) @xcite , compact proton sources for cancer therapy @xcite , laboratory astrophysics @xcite and so on .
for instance , the fi by proton beams to transport a few of meters to the dense core usually requires a high beam quality @xcite .
however , the coupling efficiency from laser to protons is too low to achieve the enough ignition energy . therefore , how to gain a high quality beam with high energy , low energy spread and small size is a challenge topic currently . in the past years.
Please generate the next two sentences of the article | , several acceleration schemes have been proposed and studied for obtaining higher quality proton beams by many researchers . according to the parameters variety of the laser and targets
, the acceleration approaches are usually classified into target normal sheath acceleration ( tnsa ) @xcite , breakout afterburner acceleration ( boa ) @xcite , shock wave acceleration @xcite , and radiation pressure acceleration ( rpa ) @xcite , etc .. the tnsa , which has been studied rapidly and implemented in the experiments , is that protons can be accelerated to high energy through the electrostatic sheath field created by the hot electrons expanding into vacuum at the rear side of the target . nevertheless , the practical application is limited because of the obtained protons possessing a large divergence , large energy spread and low number density . moreover , in order to obtain a dense and monoenergetic beam , the rpa is proposed to efficiently accelerate the protons . |
9,699 | Suppose that you have an abstract for a scientific paper: link homotopy has been an active area of research for knot theorists since its introduction by milnor in the 1950s .
we introduce a new equivalence relation on spatial graphs called component homotopy , which reduces to link homotopy in the classical case .
unlike previous attempts at generalizing link homotopy to spatial graphs , our new relation allows analogues of some standard link homotopy results and invariants . in particular we can define a type of milnor group for a spatial graph under component homotopy , and this group determines whether or not the spatial graph is splittable .
more surprisingly , we will also show that whether the spatial graph is splittable up to component homotopy depends only on the link homotopy class of the links contained within it .
numerical invariants of the relation will also be produced . .
And you have already written the first three sentences of the full article: where knot theory studies embeddings of circles into @xmath0 , spatial graph theory studies embeddings of arbitrary graphs .
let @xmath1 be a finite abstract graph .
let @xmath2 be an embedding of @xmath1 into the @xmath3-sphere ..
Please generate the next two sentences of the article | we will call @xmath4 a _ spatial embedding of @xmath1 _ or simply a _
spatial graph_. since it is the map @xmath2 that matters in this construction , we will often refer to @xmath2 as a spatial embedding . |
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