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9,100 | Suppose that you have an abstract for a scientific paper: the influence of the relativistic covariance requirement on the optimality of the symmetric state - dependent @xmath0 cloning machine is studied .
namely , given a photonic qubit whose basis is formed from the momentum - helicity eigenstates , the change to the optimal cloning fidelity is calculated taking into account the lorentz covariance unitarily represented by wigner s little group .
to pinpoint some of the interesting results , we found states for which the optimal fidelity of the cloning process drops to @xmath1 which corresponds to the fidelity of the optimal classical cloner . also , an implication for the security of the bb84 protocol is analyzed . .
And you have already written the first three sentences of the full article: in recent years the influence of special and general relativity on quantum information processing has begun to be investigated @xcite .
staying just within the realm of special relativity , one of the natural questions is how lorentz transformations affect the properties of both massive and massless particle states .
the basic approach is through wigner s little group machinery @xcite as the poincar group is non - compact and thus without any finite - dimensional unitary representations @xcite . in this context.
Please generate the next two sentences of the article | , the entanglement properties of bipartite states @xcite composed of massive as well as massless particles have been extensively analyzed . the fundamental impact on entanglement
when the owners of both entangled subsystems are lorentz transformed @xcite has been recognized since , for physically plausible states , entanglement depends on the properties of the frame where it is measured @xcite . in this paper |
9,101 | Suppose that you have an abstract for a scientific paper: in this paper we investigate the strong gravitational lensing in a five dimensional background with gauss - bonnet gravity , so that in 4-dimensions the gauss - bonnet correction disappears . by considering the logarithmic term for deflection angle
, we obtain the deflection angle @xmath0 and corresponding parameters @xmath1 and @xmath2 .
finally , we estimate some properties of relativistic images such as @xmath3 , @xmath4 and @xmath5 . + + * keywords : * gravitational lensing ; gauss - bonnet correction + .
And you have already written the first three sentences of the full article: the deviation of the light rays in the gravitational fields is referred to gravitational lensing .
the gravitational lensing ( gl ) in the weak limit has been used to test the general relativity since its beginning @xcite .
but , this theory in the weak limit was not able to describe the high bending and looping of the light rays . hence , scientist community stated this phenomenon in the strong filed regime . in the strong field limit ,.
Please generate the next two sentences of the article | the light rays pass very close to black hole and one set of infinitive relativistic `` ghost '' images would be produce on each side of black hole .
these images are produced due to the light rays wind one or several times around the black hole before reaching to observer . at first , this phenomenon was proposed by darwin @xcite . |
9,102 | Suppose that you have an abstract for a scientific paper: we study @xmath0-electron atoms with nuclear charge @xmath1 . it is well known that , in the cationic ( @xmath2 ) high-@xmath1 region
, the atom behaves as a weakly interacting system .
the anionic ( @xmath3 ) regime , on the other hand , is characterized by an instability threshold at @xmath4 , below which the atom spontaneously emits an electron .
we construct a regularized perturbative series ( rps ) for the ionization potential of ions in an isoelectronic sequence that exactly reproduces both , the large @xmath1 and the @xmath1 near @xmath5 limits .
the large-@xmath1 expansion coefficients are analytically computed from perturbation theory , whereas the slope of the energy curve at @xmath6 is computed from a kind of zero - range forces theory that uses as input the electron affinity and the covalent radius of the neutral atom with @xmath7 electrons .
relativistic effects , at the level of first - order perturbation theory , are considered .
our rps formula is to be used in order to check the consistency of the ionization potential values for atomic ions contained in the nist database . .
And you have already written the first three sentences of the full article: since the foundation of quantum mechanics , a huge amount of data on energy levels , linewidths and other properties of atoms have been recorded . very often , such compilations are still waiting for a qualitative analysis , based on simple models . in recent articles
@xcite , on the basis of the scaling suggested by thomas - fermi theory @xcite , we have demonstrated universality in the ionization potentials and the correlation energies of atomic ions . in the present paper , we construct an analytical expression for the ionization energy of atomic ions , which is to be used in order to detect problematic values @xcite in the numbers provided by the nist database.@xcite our expression is a regularized perturbative series ( rps ) , previously employed in other contexts @xcite .
we use perturbation theory in @xmath8 @xcite in order to compute the first two coefficients of the energy series in the large-@xmath1 region ..
Please generate the next two sentences of the article | additionaly , we require our rps to reproduce the value of the ionization potential at @xmath6 ( i.e. the electron affinity ) and the slope of the curve at this point . the latter is computed from a kind of zero - range forces theory that uses as input the electron affinity and the covalent radius of the neutral atom with @xmath7 electrons .
@xcite the rps continuosly interpolates between the @xmath9 and large-@xmath1 limits for a given isoelectronic sequence . |
9,103 | Suppose that you have an abstract for a scientific paper: we derive the full phase diagram for a large family of exponential random graph models , each containing a first order transition curve ending in a critical point . .4truein .
And you have already written the first three sentences of the full article: we will treat a class of models of ` dense ' random graphs , that is , simple graphs on @xmath0 vertices in which the average number of edges is of order @xmath1 .
more specifically we will consider exponential random graphs in which dependence between the random edges is defined through some finite graph , in imitation of the use of potential energy to provide dependence between particle states in a grand canonical ensemble of statistical physics .
exponential random graphs have been widely studied ( see @xcite for a range of recent work ) since the pioneering work on the independent case by erds and rnyi @xcite ..
Please generate the next two sentences of the article | we will concentrate on the phenomenon of phase transitions which can emerge for dependent variables .
following analyses using mean - field and other uncontrolled approximations ( see @xcite ) there has recently been important progress by chatterjee and diaconis @xcite , including the first rigorous proof of singular dependence on parameters . |
9,104 | Suppose that you have an abstract for a scientific paper: observations of transition region emission in solar active regions represent a powerful tool for determining the properties of hot coronal loops . in this letter we present the analysis of new observations of active region moss taken with the extreme ultraviolet imaging spectrometer ( eis ) on the _ hinode _ mission .
we find that the intensities predicted by steady , uniformly heated loop models are too intense relative to the observations , consistent with previous work . to bring the model into agreement with the observations a filling factor of about 16%
is required .
furthermore , our analysis indicates that the filling factor in the moss is nonuniform and varies inversely with the loop pressure . .
And you have already written the first three sentences of the full article: understanding how the solar corona is heated to high temperatures is one of the most important problems in solar physics . in principle
, observations of emission from the solar corona should reveal important characteristics of the coronal heating mechanism , such as the time scale and location of the energy release . in practice , however , relating solar observations to physical processes in the corona has proved to be very difficult .
one of the more significant obstacles is the complexity of the solar atmosphere , which makes it difficult to isolate and study individual loops , particularly in the cores of solar active regions ..
Please generate the next two sentences of the article | one circumstance in which the line of sight confusion can be reduced is observations of coronal `` moss . ''
the moss is the bright , reticulated pattern observed in many euv images of solar active regions . |
9,105 | Suppose that you have an abstract for a scientific paper: * abstract : * this paper focuses on the analysis of the gravitational instability in presence of bulk viscosity both in newtonian regime and in the fully - relativistic approach . the standard jeans mechanism and the quasi - isotropic solution are treated expressing the bulk - viscosity coefficient @xmath0 as a power - law of the fluid energy density @xmath1 , _
i.e. _ , @xmath2 . in the newtonian regime ,
the perturbation evolution is founded to be damped by viscosity and the top - down mechanism of structure fragmentation is suppressed .
the value of the jeans mass remains unchanged also in presence of viscosity . in the relativistic approach
, we get a power - law solution existing only in correspondence to a restricted domain of @xmath3 . ' '' '' ' '' '' .
And you have already written the first three sentences of the full article: the aim of this work is to study the dynamics of the gravitational instability , _ i.e. _ , the evolution of scalar density perturbations , in presence of viscous effects .
viscosity can be divided in two different kinds : _ bulk viscosity _ ( bv ) @xmath0 and _ shear viscosity _ @xmath4 . in this paper , we will concentrate on the analysis of isotropic ( or almost quasi - isotropic ) cosmological models . in this respect , we can safely neglect shear viscosity since there is no displacement of matter layers wrt each other ( in the zeroth - order motion ) and this kind of viscosity represents the energy dissipation due to this feature . indeed , in presence of small inhomogeneities , such effects should be taken into account but we focus on the study of scalar density perturbations and volume changes of a given mass scale are essentially involved .
we expect that the non - equilibrium dynamics of matter compression and rarefaction is more relevant than frictions , thus , we concentrate on bv only since it outcomes from the difficulty for a thermodynamical system to follow the equilibrium configuration . in this paper ,.
Please generate the next two sentences of the article | we assume bv as function of the state parameters of the fluid following the line of the fundamental analysis due to the _ landau school _ @xcite .
in particular , we implement the so - called _ hydrodynamical description _ of the fluid , _ i.e. _ , an arbitrary state is consistently characterized by the particle - flow vector and the energy momentum tensor alone and viscosity is fixed by the macroscopic fluid parameters . in the homogeneous models |
9,106 | Suppose that you have an abstract for a scientific paper: this article studies a portfolio optimization problem , where the market consisting of several stocks is modeled by a multi - dimensional jump diffusion process with age - dependent semi - markov modulated coefficients .
we study risk sensitive portfolio optimization on the finite time horizon .
we study the problem by using a probabilistic approach to establish the existence and uniqueness of the classical solution to the corresponding hamilton - jacobi - bellman ( hjb ) equation .
we also implement a numerical scheme to investigate the behavior of solutions for different values of the initial portfolio wealth , the maturity and the risk of aversion parameter . 1 true cm * key words * portfolio optimization , jump diffusion market model , semi - markov switching , risk sensitive criterion . .
And you have already written the first three sentences of the full article: following the seminal work of markowitz @xcite , the problem of optimization of an investor s portfolio based on different criteria and market assumptions are being studied by several authors . in the mean - variance optimization approach ,
as done by markowitz , either the expected value of the portfolio wealth is optimized by keeping the variance fixed or the variance is minimized by keeping the expectation fixed .
though markowitz s mean - variance approach to portfolio is immensely useful in practice , its scope is limited by the fact that only gaussian distributions are completely determined by their first two moments . in a pioneering work merton @xcite , @xcite has introduced the utility maximization to the optimal portfolio selection ..
Please generate the next two sentences of the article | merton s approach is based on applying the method of stochastic optimal control via an appropriate hamilton - jacobi- bellman ( hjb ) equation .
the corresponding optimal dynamic portfolio allocation can also be obtained from the same equation . |
9,107 | Suppose that you have an abstract for a scientific paper: we give an overview of recent work on dirichlet branes on calabi - yau threefolds which makes contact with kontsevich s homological mirror symmetry proposal , proposes a new definition of stability which is appropriate in string theory , and provides concrete quiver categories equivalent to certain categories of branes on cy . .
And you have already written the first three sentences of the full article: dirichlet branes , discovered by dai , leigh and polchinski in 1989 , have been a central part of the dramatic progress in superstring theory of recent years .
they are the simplest solitons in string theory ; the basic definition of dirichlet brane ( d - brane ) is that it is an allowed boundary condition for a string .
@xcite although they play many physical roles , from a mathematical point of view their most salient feature is that they provide the natural context in which yang - mills theory is embedded in string theory ..
Please generate the next two sentences of the article | this has allowed physicists to rederive and better understand some of the most beautiful mathematical constructions which have been discovered in this area , such as the adhm construction of instantons and nahm s construction of monopoles .
d - branes on calabi - yau ( cy ) manifolds have been the focus of a number of recent works ( see @xcite for additional references ) . |
9,108 | Suppose that you have an abstract for a scientific paper: we present a systematic study of the effect of the ion pairing on the gas - liquid phase transition of hard - core 1:1 electrolyte models . we study a class of dipolar dimer models that depend on a parameter @xmath0 , the maximum separation between the ions that compose the dimer .
this parameter can vary from @xmath1 that corresponds to the tightly tethered dipolar dimer model , to @xmath2 , that corresponds to the stillinger - lovett description of the free ion system .
the coexistence curve and critical point parameters are obtained as a function of @xmath0 by grand canonical monte carlo techniques .
our results show that this dependence is smooth but non - monotonic and converges asymptotically towards the free ion case for relatively small values of @xmath0 .
this fact allows us to describe the gas - liquid transition in the free ion model as a transition between two dimerized fluid phases .
the role of the unpaired ions can be considered as a perturbation of this picture . .
And you have already written the first three sentences of the full article: in recent years there has been an increasing interest in phase transitions between fluid phases of different electrolyte concentrations in ionic solutions .
two different regimes have been identified experimentally @xcite .
the `` solvophobic '' regime occurs for large solvent dielectric constants that effectively turn off coulombic interactions ..
Please generate the next two sentences of the article | consequently , solvophobic phase transitions are primarily driven by unfavourable interactions between solute and solvent .
this behavior is well described by the usual theory of nonelectrolyte solutions with short range interactions , and clearly leads to ising - like critical behavior . by contrast , in the `` coulombic '' regime the solvent has a low dielectric constant and electrostatic interactions between the solute ions drive the phase separation . in this case , the phase diagrams are quite asymmetric , and apparently mean - field critical behavior has been claimed @xcite , although ising - mean field crossover has also been seen within a narrower range of temperatures around the critical than in non - ionic fluids @xcite . |
9,109 | Suppose that you have an abstract for a scientific paper: we study , analytically and numerically , phase locking of driven vortex lattices in fully - frustrated josephson junction arrays at zero temperature .
we consider the case when an ac current is applied _ perpendicular _ to a dc current .
we observe phase locking , steps in the current - voltage characteristics , with a dependence on external ac - drive amplitude and frequency qualitatively different from the shapiro steps , observed when the ac and dc currents are applied in parallel .
further , the critical current increases with increasing transverse ac - drive amplitude , while it decreases for longitudinal ac - drive . the critical current and the phase - locked current step width , increase quadratically with ( small ) amplitudes of the ac - drive . for larger amplitudes of the transverse ac - signal , we find windows where the critical current is hysteretic , and windows where phase locking is suppressed due to dynamical instabilities .
we characterize the dynamical states around the phase - locking interference condition in the @xmath0 curve with voltage noise , lyapunov exponents and poincar sections .
we find that zero temperature phase - locking behavior in large fully frustrated arrays is well described by an effective four plaquette model . .
And you have already written the first three sentences of the full article: phase locking phenomena are found in a wide variety of nonlinear driven systems in condensed matter physics.@xcite it takes place when an internal frequency of the system locks to a rational multiple of the frequency of an external ac - drive .
a simple example of this is the case of an overdamped particle moving in a tilted washboard potential , where the frequency of motion of the particle over the periodic potential can be locked to multiples of the frequency of a superimposed ac force for a finite range of the dc force ( tilt of the washboard ) . since the internal ( washboard ) frequency is proportional to the mean velocity of the particle , phase locking results in a constant mean velocity for a certain range of dc - force curve when the interference condition is satisfied .
a particularly well known realization of this effect is shapiro steps@xcite in the dc current - voltage ( @xmath0 ) characteristics of a single small area josephson junction driven by a time periodic current . within the washboard analogy outlined above.
Please generate the next two sentences of the article | , a simple analysis provides expressions for the appearance of shapiro steps at specific voltages @xcite corresponding to integer multiples of the driving frequency
. driven systems with many degrees of freedom can also exhibit phase locking . |
9,110 | Suppose that you have an abstract for a scientific paper: gravitational waves generated by the final merger of double neutron star ( dns ) binary systems are a key target for the gravitational wave ( gw ) interferometric detectors , such as ligo , and the next generation detectors , advanced ligo .
the cumulative gw signal from dns mergers in interferometric data will manifest as ` geometrical noise ' : a non - continuous stochastic background with a unique statistical signature dominated by the spatial and temporal distribution of the sources . because geometrical noise is highly non - gaussian ,
it could potentially be used to identify the presence of a stochastic gw background from dns mergers .
we demonstrate this by fitting to a simulated distribution of transients using a model for the dns merger rate and idealized gaussian detector noise . using the cosmological ` probability event horizon ' concept and recent bounds for the galactic dns merger rate
, we calculate the evolution of the detectability of dns mergers with observation time . for advanced ligo sensitivities and a detection threshold assuming optimal filtering ,
there is a 95% probability that a minimum of one dns merger signal will be detectable from the ensemble of events comprising the stochastic background during 12211 days of observation . for initial ligo sensitivities ,
we identify an interesting regime where there is a 95% probability that at least one dns merger with signal - to - noise ratio @xmath0 unity will occur during 468 days of observation .
we propose that there exists an intermediate detection regime with pre - filtered signal - noise - ratio less than unity , where the dns merger rate is high enough that the geometrical signature could be identified in interferometer data .
[ firstpage ] gravitational waves binaries : neutron stars pulsars : general supernovae . .
And you have already written the first three sentences of the full article: three long - baseline laser interferometer gw detectors have been , or are nearly , constructed .
the us ligo ( laser interferometer gravitational - wave observatory ) has started observation with two 4-km arm detectors situated at hanford , washington , and livingston , louisiana ; the hanford detector also contains a 2-km interferometer .
the italian / french virgo project is commissioning a 3-km baseline instrument at cascina , near pisa ..
Please generate the next two sentences of the article | there are detectors being developed at hannover ( the german / british geo project with a 600-m baseline , which had its first test runs in 2002 ) and near perth ( the australian international gravitational observatory , aigo , initially with an 80-m baseline ) .
a detector at tokyo ( tama , 300-m baseline ) has been in operation since 2001 . |
9,111 | Suppose that you have an abstract for a scientific paper: the two - body open charm decays @xmath0 occur through the re - scattering mechanism and their branching ratios are strongly suppressed if @xmath1 is a @xmath2 molecular state .
in contrast , @xmath1 falls apart into these modes easily with large phase space and they become the main decay modes if @xmath1 is a tetraquark state .
experimental search of these two - body open charm modes and the hidden charm mode @xmath3 will help distinguish different theoretical schemes . .
And you have already written the first three sentences of the full article: belle collaboration observed a new resonance @xmath1 in the invariant mass spectrum of @xmath4 of @xmath5 @xcite .
its mass and width are @xmath6 mev and @xmath7 mev respectively . this charged state stimulated extensive studies of its nature @xcite .
theoretical explanations of @xmath1 include the s - wave threshold effect @xcite , the @xmath8 molecular state @xcite , the tetraquark state @xcite , the cusp effect @xcite and the @xmath9 bound state @xcite ..
Please generate the next two sentences of the article | recently we studied whether @xmath1 could be an s - wave @xmath10 ( @xmath11 ) molecular state considering both the pion and sigma meson exchange potentials @xcite .
our numerical results show that there may exist an s - wave @xmath12 molecular state with @xmath13 . |
9,112 | Suppose that you have an abstract for a scientific paper: universal single - qubit operations based on purely geometric phase factors in adiabatic processes are demonstrated by utilizing a four - level system in a trapped single @xmath0ca@xmath1 ion connected by three oscillating fields .
robustness against parameter variations is studied .
the scheme demonstrated here can be employed as a building block for large - scale holonomic quantum computations , which may be useful for large qubit systems with statistical variations in system parameters . .
And you have already written the first three sentences of the full article: experimental studies of quantum information processing ( qip ) has progressed much in recent years . in studies of qip using trapped ions , realization of small scale computation and entanglement generation with relatively high fidelity has been reported @xcite , which reveals that there is no fundamental obstacle to scaling a large number of ions .
the upcoming challenges are large - scale operations and high - fidelity gate operations toward fault - tolerant quantum computation . as a way to realize high - fidelity gate operations , quantum gates and quantum computation using geometric phase factors have recently been studied .
this originates from holonomic quantum computation ( hqc ) proposed by zanardi _.
Please generate the next two sentences of the article | et al._@xcite in hqc , degenerate multiple quantum states are utilized and unitary operations are performed by varying the system hamiltonian along a closed path in the parameter space .
the final state in the hqc is dependent only on the global property of the closed path ; therefore , hqc is considered to be robust against certain types of errors . even when diabatic evolutions of the system or nondegenerate quantum states are used , similar advantages can be expected as long as the unitary operations performed are determined by geometric phase factors [ geometric quantum computation ( gqc)@xcite ] . |
9,113 | Suppose that you have an abstract for a scientific paper: we investigate the axisymmetric magnetosphere of an aligned rotating magnetic dipole surrounded by an ideal force - free plasma .
we concentrate on the magnetic field structure around the point of intersection of the separatrix between the open and closed field - line regions and the equatorial plane .
we first study the case where this intersection point is located at the light cylinder .
we find that in this case the separatrix equilibrium condition implies that all the poloidal current must return to the pulsar in the open - field region , i.e. , that there should be no finite current carried by the separatrix / equator current sheet .
we then perform an asymptotic analysis of the pulsar equation near the intersection point and find a unique self - similar solution ; however , a light surface inevitably emerges right outside the light cylinder .
we then perform a similar analysis for the situation where the intersection point lies somewhere inside the light cylinder , in which case a finite current flowing along the separatrix and the equator is allowed .
we find a very simple behavior in this case , characterized by a 90-degree angle between the separatrix and the equator and by finite vertical field in the closed - field region .
finally , we discuss the implications of our results for global numerical studies of pulsar magnetospheres . .
And you have already written the first three sentences of the full article: the structure of the pulsar magnetosphere has been an active area of research for more that 30 years , starting with the pioneering work by goldreich & julian ( 1969 ) . despite the fact that real astrophysical radio - pulsars are believed to be oblique rotating magnetic dipoles ,
much of the theoretical effort has been devoted to a significantly simpler case of an aligned rotating magnetic dipole ( i.e. , a `` non - pulsing pulsar '' ) , in which case the problem becomes stationary and axisymmetric .
the situation becomes even more tractable if one also assumes the space around the pulsar to be filled with a plasma that , on one hand , is dense enough to shorten out the longitudinal electric fields , thus providing the basis for the ideal - magnetohydrodynamic approximation , and , on the other hand , is at the same time tenuous enough for all the non - electromagnetic forces to be negligible , thus enabling one to regard the plasma as force - free ..
Please generate the next two sentences of the article | all these simplifications have lead early on to the derivation , simultaneously by several researchers , of the main equation governing the structure of the magnetosphere , the so - called pulsar equation ( scharlemann & wagoner 1973 ; michel 1973b ; okamoto 1974 ) , which is essentially a special - relativistic generalization of the well - known force - free grad
shafranov equation . |
9,114 | Suppose that you have an abstract for a scientific paper: the reductivity of a spherical curve represents how reduced the spherical curve is .
it is unknown if there exists a spherical curve whose reductivity is four . in this paper
we give an unavoidable set for spherical curves with reductivity four by considering 4-gons . .
And you have already written the first three sentences of the full article: a _ spherical curve _ , or a _ knot projection _ , is a closed curve on the 3-sphere , where each crossing is a double point and crosses transversely . in this paper
we consider spherical curves with at least one crossing .
we call each part of the sphere bounded by a spherical curve a _ region_. in particular , we call a region which has @xmath0 edges on the boundary an _ @xmath0-gon_. a crossing of a spherical curve is _ reducible _ if there are just three regions around the crossing.
Please generate the next two sentences of the article | . a spherical curve @xmath1 is reducible if @xmath1 has a reducible crossing .
@xmath1 is _ reduced _ otherwise . |
9,115 | Suppose that you have an abstract for a scientific paper: in the framework of an nonuniversal @xmath0 extension of the standard model , we propose an scalar candidate for cold dark matter which exhibits interactions with ordinary matter through higgs and gauge bosons .
using limits from low energy observables , we find constraints on the new physics parameters of the model associated to the extra abelian symmetry , in particular , the mass of the additional neutral gauge boson @xmath1 and the new gauge coupling constant .
we found that for the lower experimental limit @xmath2 tev constrained by direct research at lhc , the ratio between the @xmath0 and @xmath3 gauge coupling constants is around @xmath4 .
taking into account this limit and the observable relic density of the universe , we search for new constraints on the mass of the dark matter particle of the model .
we found that for a higgsphobic model , the mass of the scalar dark matter must be @xmath5 gev .
we also found different kinematical threshold and resonances that enhance the dispersion of dark matter into ordinary matter for different regions of the space of parameters of the model , obtaining masses as low as @xmath6 gev and as large as @xmath7 gev with not allowed intermediate regions due to resonances . .
And you have already written the first three sentences of the full article: although the standard model ( sm ) @xcite is the simplest model that successfully explains most of the phenomena and experimental observations in particle physics , there are still some unexplained observations and theoretical issues that leaves unanswered .
in particular , the astrophysical evidences of electrically neutral , non - baryonic and weakly interacting matter , i.e. dark matter ( dm ) can be naturally understood if the sm is extended .
since the evidences of dm are based only on its gravitational effects , its nature and microscopic properties remains unknown ..
Please generate the next two sentences of the article | thus , in particle physics many extensions of the sm can be proposed with new particles that naturally fits the current astrophysical data and experimental constraints in direct dm detection . among the different candidates for dm , extensions with stable and non - relativistic ( cold ) particles with masses between a few gev and 1 tev , and interacting through the weak nuclear force ( wimps ) are currently the best motivated models which provides a natural scenery for the cold dark matter ( cdm ) .
for example , supersymmetry provides a wimp candidate through the lightest neutralino @xcite . in universal extra dimension models , |
9,116 | Suppose that you have an abstract for a scientific paper: this paper compares the partial - decode - forward and the complete - decode - forward coding strategies for the half - duplex gaussian single - relay channel .
we analytically show that the rate achievable by partial - decode - forward outperforms that of the more straightforward complete - decode - forward by at most 12.5% .
furthermore , in the following asymptotic cases , the gap between the partial - decode - forward and the complete - decode - forward rates diminishes : ( i ) when the relay is close to the source , ( ii ) when the relay is close to the destination , and ( iii ) when the snr is low .
in addition , when the snr increases , this gap , when normalized to the complete - decode - forward rate , also diminishes .
consequently , significant performance improvements are not achieved by optimizing the fraction of data the relay should decode and forward , over simply decoding the entire source message . achievable rate , decode - forward , half duplex , partial decode - forward , relay channel . .
And you have already written the first three sentences of the full article: wireless relay networks are ubiquitous from classical satellite communications to the increasing use of wireless ad hoc networks where mobiles , tablets , or laptops have the ability to act as wireless relays for other similar devices .
a common coding strategy deployed in relay networks is for the relays to decode the source message , and then forward a function of the message ( e.g. , some parity bits ) to the destination to facilitate decoding . in this context , one can use a _ partial - decode - forward ( pdf ) _ scheme where the relays decode only a fraction of the source message and forward a function of the decoded part , or a _ complete - decode - forward ( cdf ) _ scheme where the relays fully decode the source message and forward a function of it .
another consideration in designing wireless relay networks is whether to use a full - duplex ( communication possible in both directions simultaneously without interference ) or a half - duplex ( communication possible in only one direction at a time ) scheme . the choice of full- versus half - duplex , as well as the choice of cdf or pdf , impacts on the achievable communication rate ..
Please generate the next two sentences of the article | achievable rates have been demonstrated for the full - duplex relay channel using cdf @xcite and pdf @xcite , ( * ? ? ?
16.3 ) , and for the half - duplex relay channel using cdf @xcite and pdf @xcite . |
9,117 | Suppose that you have an abstract for a scientific paper: we compute the @xmath0 corrections to the wilson coefficients of the dimension five operators emerging from the operator product expansion of inclusive radiative @xmath1 decays .
we discuss the impact of the resulting @xmath2 corrections on the extraction of @xmath3 and @xmath4 from the moments of the photon spectrum .
* power suppressed effects in @xmath5 at @xmath0 * 1.5 cm * thorsten ewerth , paolo gambino and soumitra nandi * + _ dip .
fisica teorica , univ .
di torino & infn torino , i-10125 torino , italy _ .
And you have already written the first three sentences of the full article: the inclusive radiative decays of the @xmath1 meson play a central role in the search for new physics . while the total rate of @xmath5 is sensitive to new physics in flavor - changing transitions ,
its photon spectrum is almost completely determined by standard model physics and can be employed to extract information on the @xmath1 meson structure and on the @xmath6 quark mass , see for instance @xcite .
the latter are useful in a number of @xmath1 physics applications , like the determination of @xmath7 and of @xmath8 , which are both important inputs for the determination of the ckm unitarity triangle and the study of cp violation in the standard model . after integrating out the heavy degrees of freedom at the electroweak scale and evolving the resulting weak hamiltonian to the @xmath6 quark mass scale ,.
Please generate the next two sentences of the article | inclusive radiative and semileptonic @xmath1 decays are well described by an operator product expansion ( ope ) in inverse powers of the @xmath6 quark mass . in this way one can factorize the long distance dynamics into the matrix elements of a few local operators @xcite . since the wilson coefficients of these operators are perturbative , and the matrix elements of the local operators parameterize the non - perturbative physics , the radiative and semileptonic rates and the moments of their distributions are double series in @xmath9 and @xmath10 , with @xmath11 being the qcd scale .
the lowest order of this expansion corresponds to the decay of a free @xmath6 quark and linear @xmath12 corrections are absent . |
9,118 | Suppose that you have an abstract for a scientific paper: in this work , we consider the possibility of expanding wormholes in higher - dimensions , which is an important ingredient of modern theories of fundamental physics .
an important motivation is that non - trivial topological objects such as microscopic wormholes may have been enlarged to macroscopic sizes in an expanding inflationary cosmological background .
since the ricci scalar is only a function of time in standard cosmological models , we use this property as a simplifying assumption .
more specifically , we consider a particular class of wormhole solutions corresponding to the choice of a spatially homogeneous ricci scalar .
the possibility of obtaining solutions with normal and exotic matter is explored and we find a variety of solutions including those in four dimensions that satisfy the null energy condition ( nec ) in specific time intervals .
in particular , for five dimensions , we find solutions that satisfy the nec throughout the respective evolution . .
And you have already written the first three sentences of the full article: wormhole physics dates back to the formulation of general relativity ( gr ) .
indeed , in 1916 , months after einstein presented his gravitational field equations , karl schwarzschild found the first solution of einstein s equations , which described the gravitational field of a vacuum non - rotating spherically symmetric solution . in the same year , ludwig flamm published a paper in which the geometry of the schwarzschild solution was studied more closely .
he pointed out a `` tunnel - shaped '' nature of space near the schwarzschild radius , this being perhaps the first move towards the modern concept of the `` throat '' in wormholes @xcite . paging through the literature , one finds next that tunnel - like solutions were considered , in 1935 , by einstein and rosen , where they constructed an elementary particle model represented by a bridge connecting two identical sheets @xcite ..
Please generate the next two sentences of the article | they considered the possibility that fundamental particles such as the electron could be represented as microscopic spacetime tunnels that convey fluxes of the electric field .
these tunnels were later denoted the _ einstein - rosen bridge_. in fact , the einstein - rosen bridge is a coordinate artifact arising from choosing a coordinate patch , which is defined to double - cover the asymptotically flat region exterior to the black hole event horizon . |
9,119 | Suppose that you have an abstract for a scientific paper: random tessellations of the space represent a class of prototype models of heterogeneous media , which are central in several applications in physics , engineering and life sciences . in this work
, we investigate the statistical properties of @xmath0-dimensional isotropic poisson geometries by resorting to monte carlo simulation , with special emphasis on the case @xmath1 .
we first analyse the behaviour of the key features of these stochastic geometries as a function of the dimension @xmath0 and the linear size @xmath2 of the domain .
then , we consider the case of poisson binary mixtures , where the polyhedra are assigned two ` labels ' with complementary probabilities . for this latter class of random geometries ,
we numerically characterize the percolation threshold , the strength of the percolating cluster and the average cluster size . .
And you have already written the first three sentences of the full article: heterogeneous and disordered media emerge in several applications in physics , engineering and life sciences .
examples are widespread and concern for instance light propagation through engineered optical materials @xcite or turbid media @xcite , tracer diffusion in biological tissues @xcite , neutron diffusion in pebble - bed reactors @xcite or randomly mixed immiscible materials @xcite , inertial confinement fusion @xcite , and radiation trapping in hot atomic vapours @xcite , only to name a few .
stochastic geometries provide convenient models for representing such configurations , and have been therefore widely studied @xcite , especially in relation to heterogeneous materials @xcite , stochastic or deterministic transport processes @xcite , image analysis @xcite , and stereology @xcite ..
Please generate the next two sentences of the article | a particularly relevant class of random media is provided by the so - called poisson geometries @xcite , which form a prototype process of isotropic stochastic tessellations : a portion of a @xmath0-dimensional space is partitioned by randomly generated @xmath3-dimensional hyper - planes drawn from an underlying poisson process . the resulting random geometry ( i.e. , the collection of random polyhedra determined by the hyper - planes ) satisfies the important property that an arbitrary line thrown within the geometry will be cut by the hyper - planes into exponentially distributed segments @xcite . in some sense ,
the exponential correlation induced by poisson geometries represents perhaps the simplest model of ` disordered ' random fields , whose single free parameter ( i.e. , the average correlation length ) can be deduced from measured data @xcite . following the pioneering works by goudsmit @xcite , miles @xcite and richards @xcite for @xmath4 |
9,120 | Suppose that you have an abstract for a scientific paper: we study the behaviour of the density contrast in quasi - spherical szekeres spacetime and derive its analytical behaviour as a function of @xmath0 and @xmath1 .
we set up the inhomogeneity using initial data in the form of one extreme value of the density and the radial profile .
we derive conditions for density extremes that are necessary for avoiding the shell crossing singularity and show that in the special case of a trivial curvature function , the conditions are preserved by evolution .
we also show that in this special case if the initial inhomogeneity is small , the time evolution does not influence the density contrast , however its magnitude homogeneously decreases . .
And you have already written the first three sentences of the full article: homogeneous cosmological models have successfully explained many important features of our universe .
however , we know that the distribution of matter is not homogeneous and so these models are only an approximation . in the last decade modelling of inhomogeneity in cosmology
has become a topic of substantial interest ..
Please generate the next two sentences of the article | there are several different approaches to the problem . due to the nonlinear nature of einstein equations one should not rely on perturbation theory completely therefore exact models with nonuniform distribution of matter
should be considered as well . among |
9,121 | Suppose that you have an abstract for a scientific paper: for a positive integer @xmath0 and a graph @xmath1 , we consider proper vertex - colourings of @xmath1 with @xmath0 colours in which all @xmath0 colours are actually used .
we call such a colouring a strong
. the strong @xmath0-colour graph of @xmath1 , @xmath2 , is the graph that has all the strong @xmath0-colourings of @xmath1 as its vertex set , and two colourings are adjacent in @xmath2 if they differ in colour on only one vertex of @xmath1 . in this paper , we show some results related to the question : for what @xmath1 and @xmath0 is @xmath2 connected ?
* keywords * : strong @xmath0-vertex - colouring , strong @xmath0-colour graph , strong colour graph . .
And you have already written the first three sentences of the full article: throughout this paper a graph @xmath1 is finite , simple , and loopless , and we also usually assume that @xmath1 is connected .
most of our terminology and notation will be standard and can be found in any textbook on graph theory such as @xcite and @xcite . for a positive integer @xmath0 and a graph @xmath1 , the _
@xmath0-colour graph _ of @xmath1 , denoted @xmath3 , is the graph that has the proper @xmath0-vertex - colourings of @xmath1 as its vertex set , and two such colourings are joined by an edge in @xmath3 if they differ in colour on only one vertex of @xmath1 ..
Please generate the next two sentences of the article | we now introduce a subgraph of @xmath3 , called the _ strong @xmath0-colour graph _ of @xmath1 , denoted @xmath2 .
its vertex set contains only proper @xmath0-colourings in which all @xmath0 colours actually appear , and we call such a colouring a _ |
9,122 | Suppose that you have an abstract for a scientific paper: i present a brief review of present cgc phenomenological applications and of the physics prospects for the forthcoming proton - lead run at the lhc color glass condensate , high - density qcd , lhc besides its crucial role as a reference experiment to calibrate initial state effects in heavy ion collisions , the forthcoming p+pb run at the lhc will provide access to kinematic regions never explored so far in nuclear collisions and thus carries great potential for discovery of new qcd phenomena on its own . in particular , the huge leap forward in collision energy with respect to previous high energy electron - nucleus or proton - nucleus experiments will probe the nuclear wave function at values of bjorken-@xmath0 smaller than ever before .
it is theoretically well established that at small enough values of bjorken-@xmath0 qcd enters a novel regime governed by large gluon densities and non - linear coherence phenomena .
the color glass condensate ( cgc ) effective theory provides a consistent framework to study qcd scattering at small-@xmath0 or high collision energies ( for a review see e.g. @xcite ) .
it is based on three main physical ingredients : first , high gluon densities correspond to strong classical fields , which permit ab - initio first principles calculation of `` wave functions '' at small @xmath0 through classical techniques .
next , quantum corrections are incorporated via non - linear renormalization group equations such as the b - jimwlk hierarchy or , in the large-@xmath1 limit , the bk equation @xcite that describe the evolution of the hadron wave function towards small @xmath0 .
the non - linear , density - dependent terms in the cgc evolution equations are ultimately related to unitarity of the theory and , in the appropriate frame and gauge , can be interpreted as due to gluon recombination processes that tame or _
saturate _ the growth of gluon densities for modes with transverse momenta below a dynamically generated scale known as the saturation scale , @xmath2 .....
And you have already written the first three sentences of the full article: a main lesson learnt from experimental data collected in ( d)au+au and pb+pb collisions at rhic and the lhc respectively is that bulk particle production in ion - ion collisions is very different from a simple superposition of nucleon - nucleon collisions .
such is evident in terms of the measured charged particle multiplicities , which exhibit a strong deviation from the scaling with the number of nucleon - nucleon collisions : @xmath7 , and also from the non - trivial transverse momentum dependence of nuclear modification factors measured in d+au collisions .
these observations lead to the conclusion that strong coherence effects among the constituent nucleons , or the relevant degrees of freedom at the sub - nucleon level , must be present during the collisions process ..
Please generate the next two sentences of the article | indeed , and regardless of the question whether the cgc is the most suited framework for their description there is broad consensus that coherence effects are essential for the interpretation of present data on heavy ion collisions .
in fact most if not all of the different phenomenological approaches for the description of particle production both in the soft or hard sector. on physical grounds , coherence phenomena are related to the presence of high gluon densities in the wave function of the colliding nuclei at small values of bjorken-@xmath0 proven in a hadronic collision can be obtained using @xmath8 kinematics @xmath9 , with @xmath10 , @xmath11 and @xmath12 being the collision energy and the transverse momentum and rapidity of the produced hadron respectively . ] |
9,123 | Suppose that you have an abstract for a scientific paper: recent events such as the global financial crisis have renewed the interest in the topic of economic networks . one of the main channels of shock propagation among countries is the international trade network ( itn ) .
two important models for the itn structure , the classical gravity model of trade ( more popular among economists ) and the fitness model ( more popular among networks scientists ) , are both limited to the characterization of only one representation of the itn .
the gravity model satisfactorily predicts the volume of trade between connected countries , but can not reproduce the observed missing links ( i.e. the topology ) . on the other hand
, the fitness model can successfully replicate the topology of the itn , but can not predict the volumes .
this paper tries to make an important step forward in the unification of those two frameworks , by proposing a new gdp - driven model which can simultaneously reproduce the binary and the weighted properties of the itn .
specifically , we adopt a maximum - entropy approach where both the degree and the strength of each node is preserved .
we then identify strong nonlinear relationships between the gdp and the parameters of the model .
this ultimately results in a weighted generalization of the fitness model of trade , where the gdp plays the role of a ` macroeconomic fitness ' shaping the binary and the weighted structure of the itn simultaneously .
our model mathematically highlights an important asymmetry in the role of binary and weighted network properties , namely the fact that binary properties can be inferred without the knowledge of weighted ones , while the opposite is not true . .
And you have already written the first three sentences of the full article: after the 2008 financial crisis , it has become clear that a better understanding of the mechanisms and dynamics underlying the networked worldwide economy is vital @xcite . among the possible channels of interaction among countries
, international trade plays a major role @xcite . combined together
, the worldwide trade relations can be interpreted as the connections of a complex network , the international trade network ( itn ) @xcite , whose understanding and modeling is one of the traditional goals of macroeconomics ..
Please generate the next two sentences of the article | the standard model of non - zero trade flows , inferring the volume of bilateral trade between any two countries from the knowledge of their gross domestic product ( @xmath0 ) and mutual geographic distance ( @xmath1 ) , is the so - called ` gravity model ' of trade @xcite . in its simplest form ,
the gravity model predicts that the volume of trade between countries @xmath2 and @xmath3 is @xmath4 note that the above expression , as well as the rest of this paper , focuses on the undirected version of the network for simplicity . in this representation |
9,124 | Suppose that you have an abstract for a scientific paper: accurate and homogeneous atmospheric parameters ( @xmath0 , @xmath1 , @xmath2 , [ fe / h ] ) are derived for 74 fgk non - variable supergiants from high - resolution , high signal - to - noise ratio , echelle spectra .
extremely high precision for the inferred effective temperatures ( 1040 k ) is achieved by using the line - depth ratio method .
the new data are combined with atmospheric values for 164 classical cepheids , observed at 675 different pulsation phases , taken from our previously published studies .
the derived values are correlated with unreddened _ b v _ colours compiled from the literature for the investigated stars in order to obtain an empirical relationship of the form : @xmath3 + 0.8833(\log g)(\log t_{\rm eff})$ ] .
the expression is used to estimate colour excesses e(_b v _ ) for individual supergiants and classical cepheids , with a precision of @xmath4 mag . for supergiants and cepheids with @xmath5 spectra , reaching @xmath6 mag . for cepheids with @xmath7 spectra , matching uncertainties for the most sophisticated photometric techniques .
the reddening scale is also a close match to the system of space reddenings for cepheids .
the application range is for spectral types f0k0 and luminosity classes i and ii .
[ firstpage ] stars : fundamental parameters stars : colour excesses stars : supergiants stars : classical cepheids . .
And you have already written the first three sentences of the full article: the cepheid period - luminosity ( pl ) relation continues to play a key role in the determination of distances within the local group and to nearby galaxies .
the absolute calibration of the pl relation requires reliable distance measurements for calibrating cepheids as well as accurate corrections for the effects of interstellar reddening and extinction .
galactic cepheids are often heavily obscured , the average colour excess e(_b v _ ) being of order 0.5 mag ..
Please generate the next two sentences of the article | here we propose a new method of accurate colour excess determination that relies on spectroscopically determined stellar parameters .
the traditional methods of establishing the interstellar reddening of cepheids have involved field reddenings derived from photometric and spectroscopic studies of stars surrounding the cepheid , the use of reddening - independent spectroscopic indices , and period - colour relations calibrated from spectroscopic analyses of a number of well - studied cepheids or supergiants . |
9,125 | Suppose that you have an abstract for a scientific paper: we present an estimator - based control design procedure for flow control , using reduced - order models of the governing equations , linearized about a possibly unstable steady state .
the reduced - order models are obtained using an approximate balanced truncation method that retains the most controllable and observable modes of the system .
the original method is valid only for stable linear systems , and in this paper , we present an extension to unstable linear systems .
the dynamics on the unstable subspace are represented by projecting the original equations onto the global unstable eigenmodes , assumed to be small in number .
a snapshot - based algorithm is developed , using approximate balanced truncation , for obtaining a reduced - order model of the dynamics on the stable subspace .
the proposed algorithm is used to study feedback control of two - dimensional flow over a flat plate at a low reynolds number and at large angles of attack , where the natural flow is vortex shedding , though there also exists an unstable steady state . for control design
, we derive reduced - order models valid in the neighborhood of this unstable steady state .
the actuation is modeled as a localized body force near the leading edge of the flat plate , and the sensors are two velocity measurements in the near - wake of the plate .
a reduced - order kalman filter is developed based on these models and is shown to accurately reconstruct the flow field from the sensor measurements , and the resulting estimator - based control is shown to stabilize the unstable steady state . for small perturbations of the steady state , the model accurately predicts the response of the full simulation .
furthermore , the resulting controller is even able to suppress the stable periodic vortex shedding , where the nonlinear effects are strong , thus implying a large domain of attraction of the stabilized steady state . .
And you have already written the first three sentences of the full article: the goal of this paper is two - fold ; the first goal is to present an algorithm for developing reduced - order models of the input - output dynamics of _ unstable _ high - dimensional linear state - space systems ( such as linearized navier - stokes equations with actuation and sensing ) , while the second goal is to demonstrate the algorithm by developing estimation - based controllers to stabilize unstable steady states of a two dimensional low - reynolds - number flow past a flat plate at a large angle of attack . development of feedback control strategies based on linearized navier - stokes equations is attractive due to the ready availability of a large class of control techniques , and there has been substantial progress in this direction in the past decade , reviewed in detail by @xcite .
however , many of these techniques are limited to relatively small dimensional systems @xmath0 , while the numerical discretization of fluid flows invariably result in huge dimensional systems , typically @xmath1 .
thus , model reduction has played an important role in making these tools further accessible to fluid flows ..
Please generate the next two sentences of the article | extensive research effort in model reduction has focused on the method of proper orthogonal decomposition ( pod ) and galerkin projection , developed first by @xcite .
the main disadvantage of this technique is that , although the pod modes capture the energetically important structures of the flow , the reduced - order models obtained by the subsequent galerkin projection of the governing equations onto these modes often do not faithfully represent the dynamics . |
9,126 | Suppose that you have an abstract for a scientific paper: it was recently proposed that the electron - frame dissipation measure , the energy transfer from the electromagnetic field to plasmas in the electron s rest frame , identifies the dissipation region of collisionless magnetic reconnection [ zenitani _ et al .
_ phys .
rev .
lett . * 106 * , 195003 ( 2011 ) ] . the measure is further applied to the electron - scale structures of antiparallel reconnection , by using two - dimensional particle - in - cell simulations .
the size of the central dissipation region is controlled by the electron - ion mass ratio , suggesting that electron physics is essential .
a narrow electron jet extends along the outflow direction until it reaches an electron shock .
the jet region appears to be anti - dissipative . at the shock ,
electron heating is relevant to a magnetic cavity signature .
the results are summarized to a unified picture of the single dissipation region in a hall magnetic geometry . .
And you have already written the first three sentences of the full article: collisionless magnetic reconnection drives explosive events in space plasma environments . on the large scale
, reconnection is an mhd - scale process but is facilitated by a compact `` diffusion region '' surrounding the reconnection point , where kinetic physics plays a role . in the hall reconnection
model,@xcite it is thought that the electron diffusion region ( edr ) , where the electrons decouple from field lines , is embedded in the ion s diffusion region @xcite ..
Please generate the next two sentences of the article | the edr is related to a localized dissipation region that allows fast reconnection , and it also adjusts the overall system evolution to the outer ion physics.@xcite owing to its importance in reconnection , the edr is one of the most important targets of nasa s upcoming magnetospheric multiscale ( mms ) mission ( http://mms.space.swri.edu/ ) , which will be the first to probe the electron - scale physics .
the hall reconnection model has been recently challenged by kinetic particle - in - cell ( pic ) simulations that sufficiently resolve electron - scale structures@xcite . |
9,127 | Suppose that you have an abstract for a scientific paper: we offer the hypothesis that atomic nuclei , nucleons , and atoms possess a new type of electromagnetic moment , that we call a `` cyclo - toroid moment '' . in nuclei , this moment arises when the toroid dipole ( anapole ) moments are arrayed in the form of a ring , or , equivalently , when the magnetic moments of the nucleons are arranged in the form of rings which , in turn , constitute the surface of a torus .
we establish theoretically that the cyclo - toroid moment plays a role in the processes of the atomic shell nucleus interaction .
the existence of this moment would explain known anomalies in the internal conversion coefficients for @xmath0 transitions in nuclei .
we show also that the static cyclo - toroid nuclear moment interacts locally inside the nucleus with the vortex part of the atomic electron currents and this leads to an energy shift in atomic @xmath1 states . for the hydrogen atom
the value of this shift may be comparable in order of magnitude to the present accuracy of measurements of the lamb shift for the @xmath2 level . .
And you have already written the first three sentences of the full article: the existence of anapole moment was theoretically predicted by zeldovich fifty years ago @xcite .
the anapole moment arises in the system where currents or magnetic moments of particles create a ring - like closed distribution of magnetic field lines .
a classic example of such distribution can be a magnetic field inside the toroidal solenoid over the surface of which poloidal currents flow ..
Please generate the next two sentences of the article | a less trivial example is an atomic nucleus in which spins of nucleons compose a ring with forming the corresponding configuration of the magnetic field .
the great interest to the anapole is related to fundamental investigations on the parity nonconservation in atomic - nuclear interactions @xcite . in 1997 |
9,128 | Suppose that you have an abstract for a scientific paper: we examine the power spectrum of clusters in the press - schechter ( ps ) theory and in n - body simulations to see how the power spectrum of clusters is related to the power spectrum of matter density fluctuations in the universe . an analytic model for the power spectrum of clusters for their given number density
is presented , both for real space and redshift space .
we test this model against results from n - body simulations and find that the agreement between the analytic theory and the numerical results is good for wavelengths @xmath0 mpc . on smaller scales non - linear processes that are not considered in the linear ps approximation influence the result .
we also use our analytic model to study the redshift - space power spectrum of clusters in cold dark matter models with a cosmological constant ( @xmath1cdm ) and with a scale - invariant harrison - zeldovich initial spectrum of density fluctuations .
we find that power spectra of clusters in these models are not consistent with the observed power spectra of the apm and abell - aco clusters .
one possible explanation for the observed power spectra of clusters is an inflationary scenario with a scalar field with the potential that has a localized steplike feature .
we use the ps theory to examine the power spectrum of clusters in this model . .
And you have already written the first three sentences of the full article: clusters of galaxies are efficient tracers of the large - scale structure of the universe . a strong spatial correlation of clusters of galaxies ( bahcall & soneira 1983 ; klypin & kopylov 1983 ) provided some of the first evidence for the existence of organized structure on large scales . to date , much effort has been devoted to determine the correlation function and the power spectrum of clusters of galaxies on large spatial scales ( e.g. postman , huchra & geller 1992 ; peacock & west 1992 ; einasto et al .
1993 ; dalton et al . 1994 ; romer et al . 1994 ; croft et al . 1997 ; einasto et al .
1997a ; retzlaff et al . 1998 ; tadros , efstathiou & dalton 1998 ) ..
Please generate the next two sentences of the article | figure 1 shows the power spectrum of the spatial distribution of the abell - aco clusters as determined by einasto et al .
( 1999 ) , and the power spectrum of the apm clusters as found by tadros , efstathiou & dalton ( 1998 ) . for comparison , |
9,129 | Suppose that you have an abstract for a scientific paper: close - range photogrammetry is widely used in many industries because of the cost effectiveness and efficiency of the technique . in this research
, we introduce an automated coded target detection method which can be used to enhance the efficiency of the photogrammetry .
photogrammetry , coded targets , decoding .
And you have already written the first three sentences of the full article: photogrammetry is a technique to determine the geometric properties of an object from a sequence of photographic images , which has a long history since 1950s .
photogrammetry can be classified into two main categories as aerial photogrammetry and close range photogrammetry ( crp ) based on the camera location during the image acquisition process . in crp
, the camera is closed to the subject and 3d models , measurements and point clouds are the most common outputs ..
Please generate the next two sentences of the article | this technique is used in different application areas , such as modeling and measuring buildings and large engineering structures , accident scenes inspection , mine inspection , quality controlling and film industry .
industrial photogrammetric measurement techniques utilize retro - reflective coded targets ( cts ) encoded with a unique identifier to signalize feature points . |
9,130 | Suppose that you have an abstract for a scientific paper: computer simulations have been employed in recent years to evaluate the configurational entropy changes in model glass - forming liquids .
we consider two methods , both of which involve the calculation of the ` intra - basin ' entropy as a means for obtaining the configurational entropy .
the first method involves the evaluation of the intra - basin entropy from the vibrational frequencies of inherent structures , by making a harmonic approximation of the local potential energy topography .
the second method employs simulations that confine the liquid within a localized region of configuration space by the imposition of constraints ; apart from the choice of the constraints , no further assumptions are made .
we compare the configurational entropies estimated for a model liquid ( binary mixture of particles interacting _ via _ the lennard - jones potential ) for a range of temperatures , at fixed density . .
And you have already written the first three sentences of the full article: whether a thermodynamic phase transition underlies the transformation of a supercooled liquid into an amorphous solid , or _
glass _ , at the laboratory glass transition temperature @xmath0 is among the central questions addressed by numerous researchers studying the supercooled liquid and glassy states .
the notion of configurational entropy@xcite has played a significant role in attempts to define and understand the thermodynamic nature of the glass transition . in recent times , there have been various attempts to determine the configurational entropy of realistic liquids analytically and by computer simulations @xcite . the purpose of this paper is to compare two such methods that have been studied recently , namely the evaluation of the configurational entropy _ via _ the analysis of local potential energy minima or _ inherent structures _ ( is)@xcite , and by the calculation of _ basin _ free energies by confining the liquid within a localized region of configuration space by the imposition of constraints@xcite . these approaches , and results from their implementation , are described in the following sections ..
Please generate the next two sentences of the article | the model liquid studied is a binary mixture of @xmath1 type @xmath2 and @xmath3 type @xmath4 particles , interacting _ via _ the lennard - jones ( lj ) potential , with parameters @xmath5 , @xmath6 , @xmath7 , and @xmath8 , and @xmath9 , which has been extensively studied as a model glass former@xcite .
results presented in sec . |
9,131 | Suppose that you have an abstract for a scientific paper: spheroidal components of spiral galaxies have been considered the only dynamically important component in gravitational lensing studies thus far . here
we point out that including the disk component can have a significant effect , depending on the disk inclination , on a variety of lensing properties that are relevant to present studies and future surveys . as an example , we look at the multiple image system b1600 + 434 , recently identified as being lensed by a spiral galaxy .
we find that including the disk component one can understand the fairly large image separation as being due to the inclination of a typical spiral , rather than the presence of a very massive halo .
the fairly low magnification ratio can also be readily understood if the disk is included .
we also discuss how such lensed systems might allow one to constrain parameters of spiral galaxies such as a disk to halo mass ratio , and disk mass scale length .
another example we consider is the quasar multiple lensing cross section , which we find can increase many fold at high inclination for a typical spiral .
finally , we discuss the changes in the gravitational lensing effects on damped lyman alpha systems ( dlas ) when disk lensing is included . .
And you have already written the first three sentences of the full article: galaxies responsible for gravitational lensing have typically been modeled as one - component systems in which the entire mass distribution of the galaxy lens , visible plus dark matter , is fairly well approximated by a singular isothermal sphere ( sis ) : @xmath0 ( see e.g. narayan and bartelmann 1997 ) .
this is probably justified for e / so galaxies where both components have a surface density fairly independent of orientation ( a small ellipticity is required only to understand the presence of four - image systems ) and the high central density represents the high density of the visible matter .
by contrast , in spiral galaxies the disk component has a very different structure from the dark matter halo and the bulge , which results in significantly different projected surface density depending on orientation ..
Please generate the next two sentences of the article | given that the projected surface density of the disk changes by a factor of radius / thickness @xmath1 between a face - on and an edge - on spiral , and that the dark and visible components are known to contribute roughly equally to the total mass within 4 5 disk scale lengths , one would expect significant effects on lensing properties for images within a couple of optical radii .
the identification of the lensing galaxy in the double image system b1600 + 434 as a nearly edge on spiral by jaunsen and hjorth ( 1997 ) gives us a perfect example to demonstrate the importance of including the disk component in modeling lensing by spirals . however , an understanding of the lensing geometry of spirals is important for several reasons besides that of modeling observed systems . |
9,132 | Suppose that you have an abstract for a scientific paper: an epidemic model with births and deaths is considered on a two dimensional @xmath0 lattice .
each individual can have global infective contacts according to the standard sir model rules or local infective contacts with its nearest neighbors .
we propose a deterministic approach to this model and verified that there is a good agreement with the stochastic simulations for different situations of the disease transmission and parameters corresponding to pertussis and rubella in the prevaccine era .
x_s keywords : epidemics ; sir ; lattice ; deterministic model ; pair approximation ; pertussis . .
And you have already written the first three sentences of the full article: mathematical modeling of infectious diseases has become an area of increasing interest in the last decades @xcite .
the development and use of mathematical models are a powerful tool to understand the complex problem of infectious disease transmission .
after the success of the simple sir compartmental model in the description of the basic and common features of the transmission process @xcite , the models have become more complex and specific for the different infectious diseases in order to help in the evaluation and design of control strategies @xcite ..
Please generate the next two sentences of the article | these complexities may include , among others , age structure of the population , immune status of the individuals , structure of the social contacts , spatial heterogeneity , etc . wherever possible , deterministic compartmental models are usually chosen because they are simple to solve numerically ,
the interpretation of results is direct , and the level of complexity may be increased gradually by adding new compartments . |
9,133 | Suppose that you have an abstract for a scientific paper: we demonstrate experimentally the guiding of cold and slow nd@xmath0 molecules along a thin charged wire over a distance of @xmath1 m through an entire molecular beam apparatus .
trajectory simulations confirm that both linear and quadratic high - field - seeking stark states can be efficiently guided from the beam source up to the detector .
a density enhancement up to a factor 7 is reached for decelerated beams with velocities ranging down to @xmath2 m/s generated by the rotating nozzle technique . .
And you have already written the first three sentences of the full article: considerable experimental effort is directed towards creating dense samples of cold molecules for precision measurements @xcite , cold chemistry experiments @xcite , quantum information processing @xcite , degenerate quantum gases with dipolar interactions @xcite , etc . established techniques for generating velocity
controlled or trapped cold molecules include the deceleration using time - varying electric @xcite , magnetic @xcite and optical fields @xcite and the velocity filtering of polar molecules out of an effusive source using static or time - varying electric fields @xcite .
alternative routes to producing cold molecules have been demonstrated utilizing the kinematics in elastically or reactively colliding molecular beams @xcite ..
Please generate the next two sentences of the article | a more general and conceptionaly simple approach to producing slow beams of cold molecules is translating a supersonic jet to low longitudinal velocities by means of a rapidly counter - rotating nozzle .
this technique was demonstrated by gupta and hershbach @xcite and recently improved in our group @xcite . using this technique |
9,134 | Suppose that you have an abstract for a scientific paper: we present a study of the x - ray properties of five galactic supernova remnants ( snrs ) kes 17 ( [email protected] ) , [email protected] , [email protected] , ctb 37a ( [email protected] ) and [email protected] that were detected in the infrared by @xcite in an analysis of data from the galactic legacy infrared mid - plane survey extraordinaire ( glimpse ) that was conducted by the _ spitzer _ space telescope .
we present and analyze archival _ asca _ observations of kes 17 , [email protected] and [email protected] , archival _ xmm - newton _ observations of kes 17 , ctb 37a and [email protected] and an archival _ chandra _ observation of ctb 37a .
all of the snrs are clearly detected in the x - ray possibly except for [email protected] .
our study reveals that the four detected snrs all feature center - filled x - ray morphologies and that the observed emission from these sources is thermal in all cases .
we argue that these snrs should be classified as mixed - morphology snrs ( mm snrs ) : our study strengthens the correlation between mm snrs and snrs interacting with molecular clouds and suggests that the origin of mixed - morphology snrs may be due to the interactions between these snrs and adjacent clouds .
our _ asca _ analysis of [email protected] reveals for the first time x - ray emission from this snr : the x - ray emission is center - filled within the radio and infrared shells and thermal in nature ( @xmath2 @xmath3 0.98 kev ) , thus motivating its classification as an mm snr .
we find considerable spectral variations in the properties associated with the plasmas of the other x - ray - detected snrs , such as a possible overabundance of magnesium in the plasma of kes 17 .
our new results also include the first detailed spatially - resolved spectroscopic study of ctb 37a using _ chandra _ as well as a spectroscopic study of the discrete x - ray source cxou j171428.5@xmath1383601 , which may be a neutron star associated with ctb 37a .
finally , we also estimate such properties as electron....
And you have already written the first three sentences of the full article: @xcite presented a search for infrared counterparts to galactic supernova remnants ( snrs ) that were sampled by the galactic legacy infrared mid - plane survey extraordinaire ( glimpse ) legacy survey @xcite .
the glimpse survey imaged the inner galactic plane specifically the galactic latitude and longitude ranges of @xmath10@xmath11@xmath10@xmath121@xmath13 and 10@xmath13@xmath14@xmath15@xmath1665@xmath13 , respectively at four wavelength bands ( 3.6 , 4.5 , 5.8 and 8.0 @xmath17 m ) with the infrared array camera ( irac ) @xcite aboard the
_ spitzer space telescope _.
Please generate the next two sentences of the article | the results presented by @xcite were very intriguing : of the 95 snrs known ( at the time ) that were sampled by glimpse , eighteen snrs were detected ( many for the first time ) and the infrared emission from these sources typically coincided ( at least partially ) with known radio structures . @xcite also presented simple models to generate template colors in the irac bands for the primary emission mechanisms expected from snrs .
these primary emission mechanisms include the following : ( i ) _ molecular _ line colors that were estimated using a three temperature component h@xmath18 excitation model based on numerous h@xmath18 lines detected toward ic 443 @xcite , ( ii ) _ ionized _ gas line colors that were estimated based on hydrogen recombination as well as the dominant fine - structure lines of iron and argon ( assuming solar abundances ) and ( iii ) interstellar medium ( ism ) polycyclic aromatic hydrocarbon ( pah ) colors that were estimated using a spectrum of the reflection nebula ngc 7023 . in their analysis |
9,135 | Suppose that you have an abstract for a scientific paper: we present deep ( @xmath0 ) _ v_- and _ i_-band stellar photometry of g302 and g312 , two globular star clusters in the halo of m31 .
these data were obtained using the _ hubble space telescope _ s wide field / planetary camera 2 .
we find iron abundances of @xmath1}}= -1.85 \pm 0.12 $ ] for g302 and @xmath1}}= -0.56 \pm 0.03 $ ] for g312 , consistent with spectroscopic measurements . the color
magnitude diagrams for each cluster show no evidence for an intermediate - aged population of stars , or a second parameter effect in the morphology of the horizontal branch .
g302 shows no evidence for a color gradient but the inner regions of g312 are bluer than the outer regions .
g312 shows no evidence of ellipticity or an extended halo of unbound stars .
g302 has a projected ellipticity of @xmath2 with the projected major axis oriented towards the center of m31 .
g302 also shows evidence of an extended asymmetric stellar halo extending to at least twice the fitted michie
king tidal radius .
the amount of mass beyond the tidal radius of g302 is consistent with the stellar escape rates which have been predicted by @xmath3-body simulations of globular clusters in the galactic tidal field . .
And you have already written the first three sentences of the full article: globular star clusters ( gcs ) are pressure - supported collections of between @xmath4 and @xmath5 stars which are usually associated with galaxies , although there is evidence that some clusters of galaxies contain a population of `` free '' gcs which are associated with the cluster potential as a whole and not any individual galaxy ( west et al . 1995 ) .
individual galactic gcs are made up of stars with a single overall chemical abundance suggesting that they formed in a single star formation event .
gcs typically have integrated magnitudes of @xmath6 making gc systems visible out to redshifts of @xmath7 , the approximate distance to the great wall galaxies ..
Please generate the next two sentences of the article | the shape of the gc luminosity function ( lf ) has been assumed to be universal , so the gc lf has been used as a distance indicator ( see harris 1991 for a review ) .
however , recent work has suggested that the shape of the gc lf may depend on the metallicity of the gc system ( ashman et al . |
9,136 | Suppose that you have an abstract for a scientific paper: + in a recent publication @xcite we have shown using a qed approach that , in the presence of a magnetic field , the quantum vacuum coupled to a chiral molecule provides a kinetic momentum directed along the magnetic field . here
we explain the physical mechanisms which operate in the transfer of momentum from the vacuum to the molecule .
we show that the variation of the molecular kinetic energy originates from the magnetic energy associated with the vacuum correction to the magnetization of the molecule .
we carry out a semiclassical calculation of the vacuum momentum and compare the result with the qed calculation . .
And you have already written the first three sentences of the full article: it is well known that the quantum fluctuations of the electromagnetic ( em ) field coupled to electric charges generate an observable interaction energy @xcite .
the fluctuations which mediate the self - interaction of electrons bound to atomic nuclei give rise to the lamb shift of atomic levels ; the fluctuations which mediate the interaction between nearby molecules generate van - der - waals energies ; and finally the fluctuations between macroscopic dielectrics generate the casimir energy .
direct observation of these energies is possible by spectroscopy , atomic interferometry or nanomechanical means @xcite ..
Please generate the next two sentences of the article | + less well - known is the fact that other observable quantities , functions of the em field , can be influenced by quantum fluctuations under certain symmetry conditions .
that is , when the time - space symmetries of the medium to which the fluctuations couple are compatible with the symmetries of some observable operator , the expectation value of that operator in the vacuum state of the system medium - em field may take a non - zero value . |
9,137 | Suppose that you have an abstract for a scientific paper: nucleation is an activated process in which the system has to overcome a free energy barrier in order for a first - order phase transition between the metastable and the stable phases to take place . in the liquid - to - solid transition
the process occurs between phases of different symmetry , and it is thus inherently a multi - dimensional process , in which all symmetries are broken at the transition . in this focus article , we consider some recent studies which highlight the multi - dimensional nature of the nucleation process . even for a single - component system ,
the formation of solid crystals from the metastable melt involves fluctuations of two ( or more ) order parameters , often associated with the decoupling of positional and orientational symmetry breaking . in other words ,
we need at least two order parameters to describe the free - energy of a system including its liquid and crystalline states .
this decoupling occurs naturally for asymmetric particles or directional interactions , focusing here on the case of water , but we will show that it also affects spherically symmetric interacting particles , such as the hard - sphere system .
we will show how the treatment of nucleation as a multi - dimensional process has shed new light on the process of polymorph selection , on the effect of external fields on the nucleation process , and on glass - forming ability . .
And you have already written the first three sentences of the full article: during a first - order phase transition , the system has to overcome a free energy barrier in order to transform to the thermodynamically stable phase .
when this process is driven only by thermal fluctuations , it is called _ homogeneous nucleation_. more often , nucleation is facilitated by external surfaces and the corresponding process is known as _
heterogeneous nucleation_. nucleation is an important process for its many practical applications , as it is ubiquitous in various types of technologically important materials such as metals , semiconductors , pharmaceuticals , and foods ..
Please generate the next two sentences of the article | nucleation has been thoroughly studied ( for recent reviews see for example refs .
@xcite ) , but it is still not entirely understood , due to the experimental difficulty in accessing the small size of the crystalline nuclei involved in the transition ( which is of the order of 10 - 1000 molecules in usual conditions ) . |
9,138 | Suppose that you have an abstract for a scientific paper: we investigate spin - dependent conductance through a quantum aharonov - bohm ring containing localized electrons which interact with the propagating flow of electrons via exchange interaction of the ferromagnetic or antiferromagnetic type .
we analyze the conductance oscillations as a function of both the chemical potential determined by the concentration of the carriers and external magnetic field .
it is demonstrated that the amplitude of the conductance oscillations in the ballistic regime is governed by the value of the non - compensated spin localized in the ring .
the results are in agreement with the concept of fractional quantization of the ballistic conductance , proposed by us earlier [ phys .
rev .
b 71,113311 ( 2005 ) ] . .
And you have already written the first three sentences of the full article: recent progress in nanotechnology has allowed to prepare quasi one - dimensional ( 1d ) semiconductor systems containing high - mobility charge carriers , which exhibit ballistic behavior in the regime when the decoherence time is longer than the characteristic time needed for an electron or a hole to pass through the structure . in this case
the transport of charge carriers in such systems is of coherent nature .
since the ballistic transport is not accompanied by the joule losses , the conductance of the quasi 1d semiconductor systems in a single mode regime at small drain - source biases depends only on the transmission coefficient describing the elastic scattering in the ballistic region @xcite ..
Please generate the next two sentences of the article | the latter is determined by the geometry of the system and can depend on such parameters , as the fermi energy of the carriers and external electric or magnetic fields . in some cases
, the scattering becomes spin - dependent . |
9,139 | Suppose that you have an abstract for a scientific paper: this is an attempt to construct a _ classical _ microscopic model of the electron which underlies quantum mechanics .
an electron is modeled , not as a point particle , but as the end of an electromagnetic string , a line of flux .
these lines stretch across cosmic distances , but are almost unobservable because they condense into pairs which form the ether .
photons are modeled to propagate on these line pairs , which act effectively as wave guides .
these line pairs are also responsible for the force of gravity which is electromagnetic in character . using our classical interpretation of an electron as a quantized electromagnetic field
, we find that we achieve a natural interpretation of not only quantum mechanics , but also mass , spin , mach s principle , gravity , self interactions , newton s second law of motion , the quantization of the photon , wave - particle duality , inflation , dark energy , agn jets , the pauli exclusion principle , superconductivity , and the quantum hall effects .
mass generation and inflation are discussed without the use of scalar fields .
we attempt to calculate newton s gravitational constant g , the mass of the electron , the spin of the electron , and the spin of the photon all in terms of planck s constant , the charge of the electron , the outer radius of a line , and the distribution of matter in the universe .
the predictions of this model and the standard model are both compared to experiment , emphasizing areas where the predictions differ .
this model s remaining problems are discussed .
this model is a classical field theory of interacting strings which explains a large number of diverse phenomena , even though it does not discuss the strong or weak interactions .
since the ether of this model is quite well determined , it might be useful in restricting the landscape of vacua in more complete string theories . .
And you have already written the first three sentences of the full article: in the year 2000 the standard model was believed to be consistent with all known experimental facts ( except the possible existence of a neutrino mass ) .
yet there are many aspects of the standard model which are assumed but not explained : the wave nature of matter , the quantization of the photon ( @xmath0 ) , and newton s second law of motion .
in addition gravity is not usually considered to be part of the standard model , but a separate interaction . with the clear measurement of dark energy by the wmap collaboration@xcite.
Please generate the next two sentences of the article | , it became important to know what makes up the majority of our universe .
the explanation apparently does not lie within the standard model . |
9,140 | Suppose that you have an abstract for a scientific paper: this is an addition to a series of papers @xcite , where we develop quaternionic analysis from the point of view of representation theory of the conformal lie group and its lie algebra . in this paper
we develop split quaternionic analogues of certain results from @xcite .
thus we introduce a space of functions @xmath0 with a natural action of the lie algebra @xmath1 , decompose @xmath0 into irreducible components and find the @xmath2-equivariant projectors onto each of these irreducible components . .
And you have already written the first three sentences of the full article: this is an addition to a series of papers @xcite , where we develop quaternionic analysis from the point of view of representation theory of the conformal lie group and its lie algebra . since the paper @xcite serves as a starting point for this article , we highlight the most relevant results .
let @xmath3 denote the algebra of quaternions , @xmath4 and @xmath5 then let @xmath6\ ] ] be the space of polynomial functions on @xmath7 .
we can think of @xmath8 as a quaternionic analogue of laurent polynomials @xmath9 $ ] . there is a natural action of the lie algebra @xmath1 on @xmath8 denoted by @xmath10 ( see lemma [ rho - algebra - action ] ) . according to theorem 7 in @xcite ( restated here as theorem [ thm7 ] ).
Please generate the next two sentences of the article | , @xmath11 decomposes into three irreducible components : @xmath12 this decomposition is followed by a derivation of projectors of @xmath8 onto its irreducible components @xmath13 , @xmath14 and @xmath15 .
these projectors are regarded as quaternionic analogues of the cauchy s formula for the second order pole @xmath16 the cases of @xmath13 and @xmath15 are fairly straightforward . on the other hand , the case of @xmath14 |
9,141 | Suppose that you have an abstract for a scientific paper: most real - world networks are not isolated . in order to function fully , they are interconnected with other networks , and this interconnection influences their dynamic processes . for example , when the spread of a disease involves two species , the dynamics of the spread within each species ( the contact network ) differs from that of the spread between the two species ( the interconnected network ) .
we model two generic interconnected networks using two adjacency matrices , a and b , in which a is a @xmath0 matrix that depicts the connectivity within each of two networks of size @xmath1 , and b a @xmath0 matrix that depicts the interconnections between the two . using an n - intertwined mean - field approximation , we determine that a critical susceptable - infected - susceptable ( sis ) epidemic threshold in two interconnected networks is @xmath2 , where the infection rate is @xmath3 within each of the two individual networks and @xmath4 in the interconnected links between the two networks and @xmath5 is the largest eigenvalue of the matrix @xmath6 . in order to determine how the epidemic threshold is dependent upon the structure of interconnected networks , we analytically derive @xmath7 using perturbation approximation for small and large @xmath8 , the lower and upper bound for any @xmath8 as a function of the adjacency matrix of the two individual networks , and the interconnections between the two and their largest eigenvalues / eigenvectors .
we verify these approximation and boundary values for @xmath7 using numerical simulations , and determine how component network features affect @xmath7 .
we note that , given two isolated networks @xmath9 and @xmath10 with principle eigenvectors @xmath11 and @xmath12 respectively , @xmath7 tends to be higher when nodes @xmath13 and @xmath14 with a higher eigenvector component product @xmath15 are interconnected .
this finding suggests essential insights into ways of designing interconnected networks to be robust against epidemics . .
And you have already written the first three sentences of the full article: complex network studies have traditionally focused on single networks in which nodes represent agents and links represent the connections between agents .
recent efforts have focused on complex systems that are comprised of interconnected networks , a configuration that more accurately represents real - world networks @xcite .
real - world power grids , for example , are almost always coupled with communication networks ..
Please generate the next two sentences of the article | power stations need communication nodes for control and communication nodes need power stations for electricity .
the influence of coupled networks on cascading failures has been widely studied @xcite . |
9,142 | Suppose that you have an abstract for a scientific paper: while the hpc community is working towards the development of the first exaflop computer ( expected around 2020 ) , after reaching the petaflop milestone in 2008 still only few hpc applications are able to fully exploit the capabilities of petaflop systems . in this paper
we argue that efforts for preparing hpc applications for exascale should start before such systems become available .
we identify challenges that need to be addressed and recommend solutions in key areas of interest , including formal modeling , static analysis and optimization , runtime analysis and optimization , and autonomic computing .
furthermore , we outline a conceptual framework for porting hpc applications to future exascale computing systems and propose steps for its implementation . .
And you have already written the first three sentences of the full article: exascale computing @xcite is expected to revolutionize computational science and engineering by providing 1000x the capabilities of currently available computing systems , while having a similar power footprint .
the total performance of the 500 systems in the 44th top500 list ( 18 nov 2014 , http://top500.org/ ) is about 0.3 exaflops .
the hpc community @xcite is now working towards the development of the first exaflop computer , expected around 2020 , after reaching the petaflop milestone in 2008 ..
Please generate the next two sentences of the article | however , only a few hpc applications are so far able to fully exploit the capabilities of petaflop systems @xcite .
examples of typical scalability for commonly used hpc applications in our organizations are provided in table [ tab : hpcapps ] . as the existing hpc applications are the major hpc asset , it is important and challenging to increase their scalability and lifetime by making them exascale - ready before 2020 . |
9,143 | Suppose that you have an abstract for a scientific paper: cold fronts sharp discontinuities recently discovered by chandra in many clusters of galaxies are believed to be due to a hot gas flow over a colder gravitationally bound gas cloud .
we analyze the stability of the fronts with respect to kelvin - helmholtz instability and show that an intrinsic width of the interface of the order of a few per cent of the curvature radius strongly limits the growth of perturbation . for the best studied case of a front in the cluster abell 3667 we conclude that current observational data on the width and extent of the front can be explained even in the absence of dynamically important magnetic fields .
epsf # 1= # 1#2=.99 = .99 # 1#2#3=.31 = .31 = .31 [ firstpage ] galaxies : clusters : individual : a3667 , x - rays : galaxies : clusters .
And you have already written the first three sentences of the full article: cold fronts were discovered as sharp features in the x - ray surface brightness distribution in chandra observations of the clusters a2142 and a3667 ( markevitch et al . , 2000 , vikhlinin , markevitch & murray , 2001a ) , see also markevitch et al .
similar features have now been found in several other clusters ( e.g. sun et al . , 2002 ,
kempner , sarazin & ricker , 2002 ) ..
Please generate the next two sentences of the article | unlike shocks , these features have lower gas temperature on the x - ray brighter side of the discontinuity .
for that reason they are called `` cold fronts '' . |
9,144 | Suppose that you have an abstract for a scientific paper: previously measured thermopower data of cenisn exhibit a significant sample dependence and non - monotonous behavior in magnetic fields . in this paper
we demonstrate that the measured thermopower @xmath0 may contain a contribution from the huge nernst coefficient of the compound , even in moderate fields of 2 t. a correction for this effect allows to determine the intrinsic field dependence of @xmath0 .
the observed thermopower behavior can be understood from zeeman splitting of a v - shaped pseudogap in magnetic fields . *
introduction : * the orthorhombic system cenisn has been classified as a kondo semimetal , in which an anisotropic pseudogap opens in the density of states ( dos ) below approximately 10 k @xcite .
various experimental probes confirm the presence of a finite quasiparticle dos at the fermi level , such as the metal - like resistivities of samples with high purity @xcite and the linear - in-@xmath1 dependence of the thermal conductivity below 0.3 k @xcite .
magnetic fields of the order of 10 t along the easy magnetic @xmath2 axis suppress the gap formation significantly , while fields along @xmath3 and @xmath4 are less effective @xcite .
the thermopower @xmath5 of cenisn is highly anisotropic and exhibits a significant sample dependence @xcite .
below 10 k , the absolute values of @xmath5 are enhanced , which has been attributed to the gap formation in this temperature range @xcite .
consequently , application of a magnetic field of 8 t along the easy @xmath2 axis has been found to induce a significant lowering of the thermopower along @xmath2 , @xmath6 , at low @xmath1 @xcite .
however , the experimental data for @xmath7 and @xmath8 with @xmath9 are inconsistent .
first measurements at 4.2 k and 1.3 k showed a lowering of @xmath8 in magnetic fields @xcite , while investigations on samples of higher purity revealed an increasing @xmath8 upon increasing field @xcite .
likewise , for @xmath7 at 1.3 k either a monotonous decrease up to 10 t @xcite or....
And you have already written the first three sentences of the full article: 9 g. nakamoto _ et al . _ , j. phys .
soc . jpn . * 64 * , 4834 ( 1995 ) ..
Please generate the next two sentences of the article | |
9,145 | Suppose that you have an abstract for a scientific paper: we develop a feature allocation model for inference on genetic tumor variation using next - generation sequencing data . specifically , we record single nucleotide variants ( snvs ) based on short reads mapped to human reference genome and characterize tumor heterogeneity by latent haplotypes defined as a scaffold of snvs on the same homologous genome . for multiple samples from a single tumor , assuming that each sample is composed of some sample - specific proportions of these haplotypes , we then fit the observed variant allele fractions of snvs for each sample and estimate the proportions of haplotypes . varying proportions of haplotypes across samples is evidence of tumor heterogeneity since it implies varying composition of cell subpopulations .
taking a bayesian perspective , we proceed with a prior probability model for all relevant unknown quantities , including , in particular , a prior probability model on the binary indicators that characterize the latent haplotypes .
such prior models are known as feature allocation models .
specifically , we define a simplified version of the indian buffet process , one of the most traditional feature allocation models .
the proposed model allows overlapping clustering of snvs in defining latent haplotypes , which reflects the evolutionary process of subclonal expansion in tumor samples .
./style / arxiv - general.cfg , , .
And you have already written the first three sentences of the full article: we propose a feature allocation model [ broderick , jordan and pitman ( @xcite ) ] to describe tumor heterogeneity using next - generation sequencing ( ngs ) data .
we use a variation of the indian buffet process ( ibp ) [ @xcite ] .
the feature allocation in our model is latent ..
Please generate the next two sentences of the article | that is , the features are not directly observed .
we record point mutations as single nucleotide variants ( snvs ) , each of which is defined as a dna locus that possesses a variant sequence from that on the reference human genome . |
9,146 | Suppose that you have an abstract for a scientific paper: transport and magnetic studies of pbtase@xmath0 under pressure suggest existence of two superconducting phases with the low temperature phase boundary at @xmath1 gpa that is defined by a very sharp , first order , phase transition . the first order phase transition line can be followed via pressure dependent resistivity measurements , and is found to be near 0.12 gpa near room temperature .
transmission electron microscopy and x - ray diffraction at elevated temperatures confirm that this first order phase transition is structural and occurs at ambient pressure near @xmath2 k. the new , high temperature / high pressure phase has a similar crystal structure and slightly lower unit cell volume relative to the ambient pressure , room temperature structure .
based on first - principles calculations this structure is suggested to be obtained by shifting the pb atoms from the @xmath3 to @xmath4 wyckoff position without changing the positions of ta and se atoms .
pbtase@xmath0 has an exceptionally pressure sensitive , structural phase transition with @xmath5 k / gpa near 4 k , this first order transition causes an @xmath6 k ( @xmath7 ) step - like decrease in @xmath8 as pressure is increased through 0.25 gpa . .
And you have already written the first three sentences of the full article: although pbtase@xmath0 was discovered several decades ago , @xcite its electronic structure and physical properties have only been studied in detail over the past few years .
@xcite structurally , pbtase@xmath0 can be thought of as alternating stacking of hexagonal tase@xmath0 and pb layers with the @xmath9 space group .
the crystal structure of pbtase@xmath0 is non - centrosymmetric . @xcite initially , only the values of resistivity and hall coefficient at 300 k of a pressed powder pellet of pbtase@xmath0 and resistive onset of superconductivity at @xmath10 k were reported ..
Please generate the next two sentences of the article | @xcite recently pbtase@xmath0 was identified as a topological , nodal semimetal with strong spin - orbit coupling .
@xcite its superconducting transition temperature in polycrystalline samples @xcite and in single crystals @xcite based on thermodynamic and transport measurements was established to be @xmath11 k. thermal conductivity and london penetration depth measurements @xcite suggested a nodeless superconducting gap structure for this material . |
9,147 | Suppose that you have an abstract for a scientific paper: we study the angular momentum mixing effects in the color superconductor with non - spherical pairing .
we first clarify the concept of the angular momentum mixing with a toy model for non - relativistic and spinless fermions .
then we derive the gap equation for the polar phase of dense qcd by minimizing the cjt free energy .
the solution of the gap equation consists of all angular momentum partial waves of odd parity .
the corresponding free energy is found to be lower than that reported in the literature with @xmath0-wave only . .
And you have already written the first three sentences of the full article: the properties of quark matter at extreme conditions have been an active research area both theoretically and experimentally . at high temperature , the quark - gluon plasma(qgp )
has long been searched by colliding two nuclei at sufficiently high energy . on the other side
, we expect that quark matter becomes color superconducting through a phase transition at high baryon density but low temperature@xcite , which is the typical condition inside compact stars . in a typical metallic superconductor , the electrons pair with equal chemical potential near the fermi surface ..
Please generate the next two sentences of the article | the situation with a quark matter , however , is much more complicated . while the quark - quark interaction favors pairing between quarks of different flavors , the mass difference among @xmath1 , @xmath2 and @xmath3 together with the charge neutrality requirement induces a substantial mismatch among their fermi momenta at the baryon density inside a compact star and thereby reduces the available phase space for cooper pairing .
a number of exotic color superconductivity phases in the presence of mismatch have been proposed in the literature@xcite , but a consensus point of view of the true ground state has not been reached . |
9,148 | Suppose that you have an abstract for a scientific paper: our current knowledge of the quark - gluon plasma in thermodynamical equilibrium is reviewed .
the phase diagram of strongly interacting matter is discussed , with emphasis on the quark - hadron phase transition and the color - superconducting phases of quark matter .
lattice qcd results on the order of the phase transition , the thermodynamical functions , the heavy quark free energy , mesonic spectral functions , and recent results for nonzero quark chemical potential are presented . analytic attempts to compute the thermodynamical properties of strongly interacting matter , such as perturbation theory , quasiparticle models ,
`` hard - thermal - loop '' ( htl)-resummed perturbation theory , the polyakov - loop model , as well as linear sigma models are discussed .
finally , color - superconducting quark matter is considered in the limit of weak coupling . the gap equation and the excitation spectrum
are derived .
the solution of the gap equation , gap parameters in various color - superconducting phases , and critical temperatures for the transition to normal - conducting quark matter are presented .
a summary of gluon and photon properties in color superconductors is given . .
And you have already written the first three sentences of the full article: quantum chromodynamics ( qcd ) is the fundamental theory of the strong interaction .
qcd is an asymptotically free theory @xcite , i.e. , interactions between quarks and gluons become weaker as the mutual distance decreases or as the exchanged momentum increases . consequently , at very large temperatures and/or densities , the interactions which confine quarks and gluons inside hadrons should become sufficiently weak to release them @xcite .
the phase where quarks and gluons are deconfined is termed the _ quark - gluon plasma _ ( qgp ) ..
Please generate the next two sentences of the article | lattice qcd calculations have established the existence of such a phase of strongly interacting matter at temperatures larger than @xmath0 mev and zero net - baryon density .
depending on the number of quark flavors and the masses of the quarks , the transition between ordinary hadronic matter and the qgp could be a thermodynamic phase transition of first order , of second order , or simply a crossover transition . |
9,149 | Suppose that you have an abstract for a scientific paper: we present a study on the variations of the luminosity function of galaxies around clusters in a numerical simulation with semi - analytic galaxies , attempting to detect these variations in the 2df galaxy redshift survey .
we subdivide the simulation box in equal - density regions around clusters , which we assume can be achieved by selecting objects at a given normalised distance ( @xmath0 , where @xmath1 is an estimate of the halo radius ) from the group centre .
the semi - analytic model predicts important variations in the luminosity function out to @xmath2 . in brief , variations in the mass function of haloes around clusters ( large dark - matter haloes with @xmath3h@xmath4m@xmath5 ) lead to cluster central regions that present a high abundance of bright galaxies ( high @xmath6 values ) as well as low luminosity galaxies ( high @xmath7 ) ; at @xmath8 there is a lack of bright galaxies , which shows the depletion of galaxies in the regions surrounding clusters ( minimum in @xmath6 and @xmath7 ) , and a tendency to constant luminosity function parameters at larger cluster - centric distances .
we take into account the observational biases present in the real data by reproducing the peculiar velocity effect on the redshifts of galaxies in the simulation box , and also by producing mock catalogues .
we find that excluding from the analysis galaxies wich in projection are close to the centres of the groups provides results that are qualitatively consistent with the full simulation box results .
when we apply this method to mock catalogues of the 2df galaxy redshift survey ( 2dfgrs ) and the 2pigg catalogue of groups , we find that the variations in the luminosity function are almost completely erased by the finger - of - god effect ; only a lack of bright galaxies at @xmath8 can be marginally detected in the mock catalogues .
the results from the real 2dfgrs data shows a more clear detection of a dip in @xmath6 and @xmath7 for @xmath9 , consistent with the semi - analytic predictions .
....
And you have already written the first three sentences of the full article: understanding the way in which galaxies form is a key challenge facing cosmologists today .
this can be approached in different ways , of which the most important can be the study of the clustering of galaxies and the bound systems defined by their spatial distribution , and the statistical measures of the properties of galaxies and how these vary with their environment .
there have been several attempts to characterise galaxy properties as a function of local density @xcite . in particular ,.
Please generate the next two sentences of the article | studies of the variation of the luminosity function include the luminosity function of wall and void galaxies in the 2dfgrs @xcite , in the sdss @xcite , and theoretical variations in the luminosity function as a function of local galaxy density @xcite .
in this paper we concentrate on the study of the variations of the luminosity function with local density , which we characterise by the distance to the nearest group of galaxies , normalised by the group radius . |
9,150 | Suppose that you have an abstract for a scientific paper: we propose a matrix evolution equation in @xmath0-space for flavour singlet , unintegrated quark and gluon densities , which generalizes dglap and bfkl equations in the relevant limits .
the matrix evolution kernel is constructed so as to satisfy renormalization group constraints in both the ordered and antiordered regions of exchanged momenta @xmath1 , and incorporates the known nlo anomalous dimensions in the @xmath2 scheme as well as the nl@xmath3 bfkl kernel .
we provide a hard pomeron exponent and effective eigenvalue functions that include the @xmath4-dependence , and give also the matrix of resummed dglap splitting functions .
the results connect smoothly with those of the single - channel approach .
the novel @xmath5 splitting functions show resummation effects delayed down to @xmath6 , while both @xmath7 entries show a shallow dip around @xmath8 , similarly to the @xmath9 single - channel results .
we remark that the matrix formulation poses further constraints on the consistency of a bfkl framework with the @xmath2 scheme , which are satisfied at nlo , but marginally violated by small @xmath10-suppressed terms at nnlo .
cern - ph - th/2007 - 104 + dff 436/07/07 + july 2007 * a matrix formulation for small-@xmath11 singlet evolution * m. ciafaloni@xmath12 , d. colferai@xmath13 , g.p .
salam@xmath14 and a.m. stato@xmath15 + @xmath12 _ cern , department ph - th , ch-1211 geneva 23 , switzerland
_ + @xmath13 _ dipartimento di fisica , universit di firenze , 50019 sesto fiorentino ( fi ) , italy _ ; + _ infn sezione di firenze , 50019 sesto fiorentino ( fi ) , italy _
+ @xmath14 _ lpthe , universit p. et m. curie
paris 6 , universit d. diderot
paris 7 , cnrs umr 7589 , paris , france _
+ @xmath15 _ department of physics , pennsylvania state university , university park , 16802 pa , usa _ ; + + .
And you have already written the first three sentences of the full article: small - x qcd evolution , historically based on dglap @xcite and bfkl @xcite dynamics , has been widely investigated in the past years @xcite , leading to a better understanding of the two approaches just mentioned and to robust resummed predictions for the gluon density and splitting function @xcite .
there is now a remarkable consensus @xcite among various resummation approaches on the resulting gluon evolution kernel , and a satisfactory comparison of some of them to experimental data @xcite .
the basic idea underlying the progress of the resummation approaches just mentioned , lies in the observation @xcite that the bfkl kernel embodies an infinite number of subleading contributions which are collinear singular ..
Please generate the next two sentences of the article | these terms are parametrically large and need to be taken into account in order to achieve consistency with the renormalization group ( rg ) .
the techniques for incorporating such terms differ in detail according to the various authors , but lead eventually to similar results . |
9,151 | Suppose that you have an abstract for a scientific paper: we examine the v@xmath0 velocities and tully - fisher distances of 83 sci galaxies and find that their velocities contain the same discrete velocity components identified previously by tifft . after removing the discrete velocity components ,
the scatter remaining on the hubble plot is in good agreement with the tully - fisher distance uncertainties .
although there is , as yet , no physical explanation for these discrete components , the fact that they appear to be identical to those found previously by tifft suggests that their reality needs to be taken seriously . .
And you have already written the first three sentences of the full article: @xcite found families of discrete velocities in normal galaxies and fitted them to a model in which they were all harmonically related to @xmath1 the speed of light . in his model
the discrete components detected are octave - spaced sub - harmonics of @xmath1 , and related harmonics , and the redshift is assumed to arise from a time - dependent decay from an origin at the planck scale .
his observed velocity periods can be accurately described by the relation p = @xmath2 , where d is the number of doublings and t defines the different families ..
Please generate the next two sentences of the article | there can be many different families but the most common , or basic , of these make up what is referred to by @xcite as the t = 0 family of discrete values .
these were found in common spiral galaxies . |
9,152 | Suppose that you have an abstract for a scientific paper: in supersymmetric models a tree - level neutrino mass could originate from the ( weak - scale ) superpotential .
we propose and examine a realization of that idea , which arises naturally in the framework of a spontaneously broken @xmath0 @xmath1-symmetry .
the solution to the neutrino mass problem could shed light in this framework on the possible resolution of the @xmath2 problem .
furthermore , the suppression of the neutrino mass in comparison to the weak scale arises dynamically and need not be encoded in the superpotential .
the latter mechanism operates , for example , in universal models for the soft supersymmetry breaking terms .
phenomenological and cosmological implications of the model are also discussed , some of which are shown to hold more generally .
we also note that future signatures could include observable enhancement of dijet and multijet production rates and a correlation between the supersymmetric and neutrino spectra . .
And you have already written the first three sentences of the full article: within the framework of the standard model of the electroweak and strong interactions the neutrinos are massless to all orders in perturbation theory . however , it is widely believed , based on the interpretation of current observations , that the neutrinos are massive and light , i.e. , @xmath31 - 100 ev ) @xcite .
if confirmed by future experiments ( e.g. , the next generation of underground observatories and the long - baseline oscillation experiments ) the massive neutrinos would provide an unambiguous signal of physics beyond the standard model ( sm ) . for example , the small neutrino masses are often attributed to some sort of a see - saw mechanism involving an intermediate scale @xmath4 gev ) right - handed neutrino ( or some other structure at that scale ) , i.e. , @xmath5 @xcite .
the neutrino mass in that case is a signal of the physics at intermediate scales ..
Please generate the next two sentences of the article | a different and most interesting possibility is that the neutrino mass is a signal of weak - scale physics . indeed
, this could be the case within a supersymmetric framework @xcite as it could incorporate a new and novel ( but often overlooked ) mechanism for the generation of neutrino masses which was first proposed by hall and suzuki @xcite . |
9,153 | Suppose that you have an abstract for a scientific paper: we investigate the rosat x - ray properties of v sge , which has been proposed to be related to supersoft x - ray binaries . during optical bright states , v sge is a faint hard x - ray source , while during optical faint states ( @xmath0 mag ) , v sge is a ` supersoft ' x - ray source .
spectral fitting confirms that v sge s x - ray properties during its soft x - ray state may be similar to those of supersoft x - ray binaries , although a much lower luminosity can not be excluded .
it is possible to explain the different optical / x - ray states by a variable amount of extended uneclipsed matter , which during the optical bright states contributes significantly to the optical flux and completely absorbes the soft x - ray component .
an additional , perhaps permanent , hard x - ray component , such as a bremsstrahlung component with a 0.12.4kev luminosity of @xmath1ergs@xmath2 , must be present to explain the x - ray properties during the optical bright / hard x - ray state . .
And you have already written the first three sentences of the full article: v sge is a blue star with a mean brightness around 11 mag which has been shown to vary between 9.614.7 mag since its discovery in 1902 .
it shows wide eclipses at a period of 051419 , a small secondary eclipse , and complex emission line behaviour ( herbig 1965 ) .
extinction estimates vary between @xmath3 ( herbig 1965 ) and @xmath4 ( verbunt 1987 ) implying a distance of 0.72.7 kpc ..
Please generate the next two sentences of the article | supersoft x - ray binaries ( ssb ; see greiner 1996 and references therein ; van teeseling 1998 ) were established as a new class of accreting binaries during the early 90ies with rosat ( trmper 1991 ; greiner 1991 ) and are thought to contain white dwarfs accreting mass at rates sufficiently high to allow stable nuclear surface burning of the accreted matter ( van den heuvel 1992 ) .
ssb have luminosities of @xmath5 10@xmath610@xmath7 ergs s@xmath2 , but their characteristic temperatures of 2040 ev imply strong attenuation by the interstellar medium . |
9,154 | Suppose that you have an abstract for a scientific paper: the reactions of relevance for stellar evolution are difficult to measure directly in the laboratory at the small astrophysical energies . in recent years
indirect reaction methods have been developed and applied to extract low - energy astrophysical s - factors .
these methods require a combination of new experimental techniques and theoretical efforts , which are the subject of this review . .
And you have already written the first three sentences of the full article: * fusion * - fusion cross sections can be calculated from the equation @xcite @xmath0 where @xmath1 is the center of mass energy , @xmath2 is the reduced wavelength and @xmath3 .
the cross section is proportional to @xmath4 , the area of the quantum wave .
each part of the wave corresponds to different impact parameters having different probabilities for fusion . as the impact parameter increases , so does the angular momentum , hence the reason for the @xmath5 term ..
Please generate the next two sentences of the article | @xmath6 is the probability that fusion occurs at a given impact parameter , or angular momentum .
sometimes , for a better visualization , or for extrapolation to low energies , one uses the concept of _ astrophysical s - factor _ , redefining the cross section as @xmath7 , \label{se}\ ] ] where @xmath8 , with @xmath9 being the relative velocity . |
9,155 | Suppose that you have an abstract for a scientific paper: high-@xmath0 metal oxides are a class of materials playing an increasingly important role in modern device physics and technology . here
we report theoretical investigations of the properties of structural and lattice dielectric constants of bulk amorphous metal oxides by a combined approach of classical molecular dynamics ( md ) - for structure evolution , and quantum mechanical first principles density function theory ( dft ) - for electronic structure analysis . using classical md based on the born - mayer - buckingham potential function within a melt and
quench scheme , amorphous structures of high-@xmath0 metal oxides hf@xmath1zr@xmath2o@xmath3 with different values of the concentration @xmath4 , are generated .
the coordination numbers and the radial distribution functions of the structures are in good agreement with the corresponding experimental data .
we then calculate the lattice dielectric constants of the materials from quantum mechanical first principles , and the values averaged over an ensemble of samples agree well with the available experimental data , and are very close to the dielectric constants of their cubic form . .
And you have already written the first three sentences of the full article: in the complementary metal oxide semiconductor ( cmos ) devices , sio@xmath3 has been the first and only choice of gate oxide material for a long time . however , with the continued decrease in the feature size of the cmos devices , sio@xmath3 is no longer reliable as a gate oxide due to the high tunneling leakage current through it at small thickness .
major research efforts are continuously being carried out in search for a suitable replacement of the sio@xmath3 as a gate material.@xcite several promising candidates are metal oxides such as hfo@xmath3,@xcite zro@xmath3@xcite and al@xmath3o@xmath5,@xcite all of which have high value of dielectric constant @xmath0 .
high-@xmath0 metal oxides in their amorphous ( a- ) form are more preferable as a gate oxide over their crystalline form due to several important advantages they provide : ( i ) isotropic physical properties ; ( ii ) no crystalline domain boundary which leads to less defects at the interface with the si substrate ; and ( iii ) good compatibility with the conventional cmos fabrication process . some alloy structures of these high-@xmath0 metal oxides are also being studied extensively@xcite and , in fact , a hf based alloy material has already been in its third generation of production as a gate oxide in the semiconductor industry and further improvements of thermal stability , dielectric constant and material preparations are underway.@xcite in clear contrary to the abundance of experimental results in the literature , theoretical studies of the structure and dielectric properties of amorphous metal oxides and their alloys are quite limited ..
Please generate the next two sentences of the article | one of the reasons is the difficulties in generating reasonable and reliable amorphous structures with the available theoretical methods .
experimentally , the high-@xmath0 materials are deposited on silicon substrate by vapor deposition followed by annealing processes at around @xmath6 k.@xcite simulating the deposition process and the resulting amorphous high-@xmath0 material structures by molecular dynamics ( md ) is extremely time consuming because . |
9,156 | Suppose that you have an abstract for a scientific paper: we find a simple criterion for the equality @xmath0 where @xmath1 and @xmath2 are schur s q - functions on infinitely many variables . .
And you have already written the first three sentences of the full article: schur s q - functions are very interesting analogues of the ( standard ) schur functions @xmath3 in several combinatorial and representation - theoretic contexts
. examples of their analogy include the shifted rsk correspondence , the shifted littlewood - richardson rule , and the character theory of representations of queer lie superalgebras . in this note
we study when certain shifted littlewood - richardson coefficients ( the @xmath4 in the language of @xcite ) are zero or one . studying questions of the same nature.
Please generate the next two sentences of the article | has been of interest to a number of authors . in particular , one should mention stembridge s recent classification of multiplicity - free products of schur functions @xcite which was generalized to p - functions in @xcite .
the related questions as to when two ribbon schur functions are equal and when a schur function is equal to a skew schur function were answered in @xcite and @xcite . here |
9,157 | Suppose that you have an abstract for a scientific paper: we present results from a monitoring campaign performed with the _ chandra x - ray observatory _ of the gravitationally lensed quasars rx j1131@xmath01231 and he 1104@xmath01805 .
we detect significant x - ray variability in all images of both quasars . the flux variability detected in image a of rx
j1131@xmath01231 is of particular interest because of its high amplitude ( a factor of @xmath1 20 ) .
we interpret it as arising from microlensing since the variability is uncorrelated with that of the other images and the x - ray flux ratios show larger changes than the optical as we would expect for microlensing of the more compact x - ray emission regions .
the differences between the x - ray and optical flux ratios of he 1104@xmath01805 are less dramatic , but there is no significant soft x - ray or dust absorption , implying the presence of x - ray microlensing in this system as well .
combining the x - ray data with the optical light curves we find that the x - ray emitting region of he 1104@xmath01805 is compact with a half - light radius @xmath2 , where the gravitational radius is r@xmath3 = 3.6 @xmath4 10@xmath5 cm , thus placing significant constraints on agn corona models .
we also find that the microlensing in he 1104@xmath01805 favors mass models for the lens galaxy that are dominated by dark matter .
finally , we better characterize the massive foreground cluster near rx j1131@xmath01231 , set limits on other sources of extended x - ray emission , and limit the fluxes of any central odd images to be 3050 ( 3@xmath6 ) times fainter than the observed images .
# 1 # 1 .
And you have already written the first three sentences of the full article: resolving the emission regions of distant quasars is beyond the current capabilities of present - day telescopes , as direct imaging of accretion disks requires angular resolutions on the order of tens of nanoarcseconds at @xmath7 @xmath1 1 . until the spatial resolution of telescopes reaches this limit
, we will have to rely on indirect methods of mapping the emission regions of quasars .
such methods include light - travel time arguments , reverberation mapping of the broad line region ( blandford & mckee 1982 ; peterson 1993 , netzer & peterson 1997 ) , reverberation mapping of the fe k@xmath8 emission region ( young & reynolds 2000 ) , occultation measurements of the central x - ray source by orbiting compton thick clouds ( risaliti et al , 2007 ) , and microlensing of the continuum and line emission regions ( e.g. , grieger et al . 1988 and 1991 ; schneider , ehlers & falco 1992 ; gould & gaudi 1997 ; agol & krolik 1999 ; yonehara et al ..
Please generate the next two sentences of the article | 1999 ; mineshige & yonehara 1999 ; chartas et al . 2002a ; popovic et al . 2003 ; blackburne et al . 2006 ; pooley et al .
2006 , 2007 ; kochanek et al . 2007 ; |
9,158 | Suppose that you have an abstract for a scientific paper: the parameters for the newly - discovered open cluster alessi 95 are established on the basis of available photometric and spectroscopic data , in conjunction with new observations .
colour excesses for spectroscopically - observed b and a - type stars near su cas follow a reddening relation described by @xmath0 , implying a value of @xmath1 for the associated dust .
alessi 95 has a mean reddening of @xmath2 s.e .
, an intrinsic distance modulus of @xmath3 s.e .
( @xmath4 s.d . ) , @xmath5 pc , and an estimated age of @xmath6 yr from zams fitting of available _ ubv _ , ccd _ bv _ , _ nomad _ , and 2mass _ jhk_@xmath7 observations of cluster stars .
su cas is a likely cluster member , with an inferred space reddening of @xmath8 and a luminosity of @xmath9 s.e . ,
consistent with overtone pulsation ( @xmath10 ) , as also implied by the cepheid s light curve parameters , rate of period increase , and _ hipparcos _ parallaxes for cluster stars .
there is excellent agreement of the distance estimates for su cas inferred from cluster zams fitting , its pulsation parallax derived from the infrared surface brightness technique , and _ hipparcos _ parallaxes , which all agree to within a few percent . .
And you have already written the first three sentences of the full article: when @xcite compiled a list of relatively bright stars visible in the national geographic - palomar observatory sky survey ( poss ) that are associated with reflection nebulosity , he noted that the distance and luminosity for one such star , the @xmath11 cepheid su cas , might be estimated using spectroscopic and photometric observations of the nearby b - type stars hd 17138 and hd 17443 , which appear to illuminate a portion of the same dust complex .
his discovery was very important , given the complete lack in existing surveys of galactic clusters lying within several degrees of the cepheid that might serve as distance indicators .
curiously , the field of su cas was not surveyed in van den bergh s earlier search of the poss for previously - undetected star clusters @xcite ..
Please generate the next two sentences of the article | the sparse group of b stars was subsequently designated as cas r2 , and used by @xcite with other r - associations to map local spiral structure in the galaxy . an initial estimate for the distance to the dust complex by @xcite yielded a value of @xmath12 pc from spectroscopic distance moduli for the three b - type stars
hd 17327 , hd 17443 , and hd 17706 , and the bright m giant hd 23475 . |
9,159 | Suppose that you have an abstract for a scientific paper: we investigate the intrinsic alignments of dark halo substructures with their host halo major - axis orientations both analytically and numerically .
analytically , we derive the probability density distribution of the angles between the minor axes of the substructures and the major axes of their host halos from the physical principles , under the assumption that the substructure alignment on galaxy scale is a consequence of the tidal fields of the host halo gravitational potential .
numerically , we use a sample of four cluster - scale halos and their galaxy - scale substructures from recent high - resolution n - body simulations to measure the probability density distribution .
we compare the numerical distribution with the analytic prediction , and find that the two results agree with each other very well .
we conclude that our analytic model provides a quantitative physical explanation for the intrinsic alignment of dark halo substructures .
we also discuss the possibility of discriminating our model from the anisotropic infall scenario by testing it against very large n - body simulations in the future . .
And you have already written the first three sentences of the full article: the dark halo substructure has recently come to one of the most lively topics in cosmology .
although the standard cosmological paradigm based on the cold dark matter ( cdm ) concept generically predicts the presence of the substructure inside the dark matter halos , there are many questions yet to be answered associated with the dark halo substructures .
the intrinsic alignment effect of the dark halo substructure is one of those questions ..
Please generate the next two sentences of the article | there are plenty of observational evidences that the major axes of the brightest cluster galaxies ( bcgs ) have a strong tendency to be aligned with that of their host clusters @xcite .
the most popular theory for the bcg alignment is the anisotropic infall scenario based on the standard hierarchical clustering model @xcite : the initial density field of cdm is web - like , interconnected by the primordial filaments @xcite . |
9,160 | Suppose that you have an abstract for a scientific paper: through @xmath0 mixing system , one can construct an asymmetry which naively seems to be a time reversal ( t ) odd quantity . in this article ,
the two processes @xmath1 and @xmath2 are used to construct the event number asymmetry .
the cp violation of kaon system denoted as @xmath3 contributes to observables and we evaluate the contribution from @xmath3 explicitly .
the asymmetry is formulated with phase convention independent parameters which are invariant under redefinition of phase of quark fields .
the overall factors of the time dependent decay rates are taken into account in this article .
furthermore , we suggest conditions for the asymmetry to be a t - odd quantity .
the one of such conditions arises due to the difference of overall factors which form the asymmetry . #
1/#1 0m_^0 .
And you have already written the first three sentences of the full article: time reversal ( t ) is a fundamental symmetry in particle physics and observation of t - asymmetry plays a crucial role to investigate the property of theoretical aspects .
babar collaboration announced their result@xcite that they observed the t - asymmetry through b - meson mixing system .
the idea of taking t - asymmetry is based on @xcite-@xcite ..
Please generate the next two sentences of the article | babar stated that the observation is the first evidence of t - violation in b - system , and babar observable naively seems to be t - asymmetry .
however , discussion in ref.@xcite shows that babar observable slightly deviates from a t - odd quantity . in this article |
9,161 | Suppose that you have an abstract for a scientific paper: we search for novel two - dimensional materials that can be easily exfoliated from their parent compounds . starting from 108423 unique ,
experimentally known three - dimensional compounds we identify a subset of 5619 that appear layered according to robust geometric and bonding criteria .
high - throughput calculations using van - der - waals density - functional theory , validated against experimental structural data and calculated random - phase - approximation binding energies , allow to identify 1844 compounds that are either easily or potentially exfoliable , including all that are commonly exfoliated experimentally .
in particular , the subset of 1053 easily exfoliable cases layered materials held together mostly by dispersion interactions and with binding energies in the range of few tens of mev@xmath0contains several hundreds of entries with few atoms per primitive cell ( 273 with less than 6 atoms , 606 with less than 12 ) , revealing a wealth of new structural prototypes , simple ternary compounds , and a large portfolio to search for optimal electronic , optical , magnetic , topological , or chemical properties .
= 1 two - dimensional ( 2d ) materials provide novel opportunities to venture into largely unexplored regions of the materials properties space . on one hand
, their ultimate thinness makes them extremely promising for applications in electronics ( e.g. , for field - effect transistors , where a reduced device size is beneficial to improve performance and reduce short - channel effects between contacts).@xcite on the other hand , the physical properties of monolayers often change dramatically from those of parent 3d materials , providing a new degree of freedom @xcite in the applications ( from thermoelectrics to spintronics ) while also unveiling novel physics ( e.g. , valley hall effect and composite excitations such as trions ) .
moreover , van - der - waals ( vdw ) heterostructures @xcite have recently emerged as an additional avenue to engineer novel properties....
And you have already written the first three sentences of the full article: the computational exfoliation protocol starts from a comprehensive initial set of bulk 3d crystal structures .
these are extracted from databases of experimental compounds , and for this study we focused on the icsd @xcite and cod @xcite , containing respectively @xmath4 ( icsd 2015.1 ) and @xmath5 entries ( cod rev .
# 171462 ) ..
Please generate the next two sentences of the article | entries containing at most @xmath6 different species are retrieved in the form of cif files @xcite using routines distributed within the aiida platform @xcite , and passed through successive cod - tools filters @xcite to correct typical syntax errors that prevent the successful reconstruction of the intended crystal structures ( see methods for more details ) .
entries with partial occupancies in the unit cell are then filtered out , together with cif files that do not provide the explicit position of one or several atoms , can not be parsed , or are obviously wrong . |
9,162 | Suppose that you have an abstract for a scientific paper: we present near - infrared and optical observations of moderately fast feii - class nova scuti 2009 ( v496 sct ) covering various phases ; pre - maximum , early decline and nebular , during the first 10 months after its discovery followed by limited observations up to 2011 april . in the initial phase
the nova spectra show prominent p cygni profiles and later all the lines are seen in emission .
the notable feature of the near - ir spectra in the early decline phase is the rare presence of the first overtone bands of carbon monoxide ( co ) in emission .
the ir spectra show clear dust formation in the expanding ejecta at later phase about 150 days after the peak brightness .
the presence of lines of elements with low ionization potentials like na and mg in the early ir spectra and the detection of co bands in emission and the dust formation in v496 sct represents a complete expected sequence in the dust formation in nova ejecta .
the light curve shows a slow rise to the maximum and a slow decline indicating a prolonged mass loss .
this is corroborated by the strengthening of p cygni profiles during the first 30 days .
the broad and single absorption components seen in many lines in the optical spectra at the time of discovery are replaced by two sharper components in the spectra taken close to the optical maximum brightness .
these sharp dips seen in the p cygni absorption components of fe ii and h i lines during the early decline phase show increasing outflow velocities .
the onset of the nebular phase is evident from the optical spectra in 2010 march . during the nebular phase
, several emission lines display saddle - like profiles . in the nebular stage ,
the observed fluxes of [ o iii ] and h lines are used to estimate the electron number densities and the mass of the ejecta .
the optical spectra show that the nova is evolved in the @xmath0 spectral sequence .
the absolute magnitude and the distance to the nova are estimated to be m@xmath1 = 7.0 @xmath2 0.2 and d = 2.9 @xmath2....
And you have already written the first three sentences of the full article: nova scuti 2009 ( v496 sct ) was discovered by nishimura on 2009 november 8.370 ut at @xmath3 = 8.8 ( nakano et al .
2009 ) on two 10s unfiltered ccd images .
the low resolution spectra obtained during the period 2009 november 9.73 ut to 10.08 ut which showed prominent h@xmath4 and h@xmath5 emission lines with p cygni components , along with the strong fe ii multiplets and o i lines indicating that v496 scuti is an fe ii class nova near maximum light ( munari et al . 2009a , balam & sarty 2009 ) ..
Please generate the next two sentences of the article | the optical observations by munari et al .
( 2009b ) showed a post - discovery brightening for about 10 days before the onset of fading with maximum brightness @xmath6 = 7.07 around 2009 november 18.716 ut . |
9,163 | Suppose that you have an abstract for a scientific paper: the planetary nebula ( pn ) population of m33 is studied via multi - fiber spectroscopy with hectospec at the mmt . in this paper
we present the spectra of 102 pne , whereas plasma diagnostic and chemical abundances were performed on the 93 pne where the necessary diagnostic lines were measured .
about 20@xmath0 of the pne are compatible with being type i ; the rest of the sample is the progeny of an old disk stellar population , with main sequence masses m@xmath13m@xmath2 and ages [email protected] gyr . by studying the elemental abundances of the pne in the m33 disk we were able to infer that : ( 1 )
there is a tight correlation between o / h and ne / h , broadly excluding the evolution of oxygen ; ( 2 ) the average abundances of the @xmath4-elements are consistent with those of regions , indicating a negligible global enrichment in the disk of m33 from the epoch of the formation of the pn progenitors to the present time ; ( 3 ) the radial oxygen gradient across the m33 disk has a slope of [email protected] dex kpc@xmath6 , in agreement , within the errors , with the corresponding gradient derived from regions .
our observations do not seem to imply that the metallicity gradient across the m33 disk has flattened considerably with time .
we report also the discovery of a pn with wolf - rayet features , pn039 , belonging the class of late [ wc ] stars # 1.#2 # 1#2 .
And you have already written the first three sentences of the full article: the galaxy m33 ( ngc 598 ) is one of the closest spiral galaxies of the local group .
the measured distance to m33 ranges from 730 kpc ( christian & schommer 1987 ) to 910 kpc ( kim et al .
2002 ) , with the most recent estimates of sarajedini et al ..
Please generate the next two sentences of the article | @xcite and bonanos et al .
@xcite in the mid - range . |
9,164 | Suppose that you have an abstract for a scientific paper: we study the origin of the ultraluminous x - ray source m82-x1 in the nearby starburst galaxy m82 .
this x - ray source is of particular interest as it is currently the best candidate intermediate mass black hole ; it is associated with a 54mhz quasi periodic oscillations with a relatively low ( @xmath0kev ) black - body temperature .
we perform detailed binary evolution calculations of 215 stars which transfer mass to a 1002000 black hole and present an empirical model for the x - ray characteristics expected for such binaries . based on the binary evolution calculations and the assumption in our simulations
we conclude that the most likely candidate for the bright x - ray source m82-x1 is a 10 - 15 star near the end of its main - sequence or slightly evolved , which transfers mass to a @xmath1 black hole .
we expect the system to be in the high / soft state . in that case
the binary will not be visible as a source of gravitational wave radiation , but other transient x - ray binaries with lower mass donors way be rather bright sources of gravitational wave radiation .
[ firstpage ] black hole physics
binaries : close galaxies : individual : m82 x - ray : binaries x - rays : individual m82-x1 .
And you have already written the first three sentences of the full article: black holes in the universe have either masses less than about 20 m@xmath2 ( orosz 2003 ) , or masses exceeding about @xmath3 ( see kormendy & richstone , 1995 , for some exceptions see fillipenko & ho 2003 ; greene & ho 2004 ) .
the first category of black holes are typically the member of a binary system in a normal galactic environment , the other type of supermassive black holes can be very bright in x , but always live in the nuclei of galaxies .
the discovery of bright x - ray sources which are not in the nuclei of galaxies has led to the suggestion that these sources may hide black holes , with a mass intermediate between 20 and @xmath3 ; we call them intermediate mass black holes ( imbh ) ..
Please generate the next two sentences of the article | bright non - nuclear x - ray sources have been known to exist since the 1980s ( watson , stanger & griffiths 1984 ) , recently with the advent of chandra and xmm these sources have attracted considerably more attention . the conventional definiton of an ultraluminous x - ray source is @xmath4 ergs / s , but for the purpose of this paper we consider only luminosities of @xmath5 ergs / s as true ulx .
this definition corresponds to the eddington luminosity of an accreting compact object of about 80 times the chandrasekhar mass . the brightest galactic x - ray binary , grs 1915 + 105 , occasionally reaches @xmath6 ergs / s , and should then , according to the earlier definition be classified as a ulx . |
9,165 | Suppose that you have an abstract for a scientific paper: it is well known that a straight nambu - goto string is an exact solution of the equations of motion when its end moves in a circular orbit . in this paper
we investigate the shape of a confining relativistic string for a general motion of its end .
we determine analytically the shape of the curved string to leading order in deviation from straightness , and show that it reduces to an expected non - relativistic result .
we also demonstrate numerically that in realistic meson models this deviation is always small .
we further find that the angular momentum and energy are the same as for the straight string , but that the curved string has a small radial momentum not present in a straight string .
our results justify the common assumption of straight strings usually made in hadron models .
epsf 6.5 in 8.5 in 0.0 in -20 pt .
And you have already written the first three sentences of the full article: for some time flux tube models @xcite and wilson loop expansion calculations @xcite have been used to understand hadron states .
the usual assumption is that the color field can be taken to lie on straight lines connecting the quarks .
this `` straight line '' or `` rigid '' flux configuration is in the spirit of an adiabatic or born - oppenheimer approximation that is assumed to hold at least for slowly moving quarks ..
Please generate the next two sentences of the article | nesterenko @xcite points out that this adiabatic approximation can not be valid if the quark has angular acceleration .
the argument is based on a classic theorem of ruled surfaces . |
9,166 | Suppose that you have an abstract for a scientific paper: the speed of growth for a particular stochastic growth model introduced by borodin and ferrari in @xcite , which belongs to the kpz anisotropic universality class , was computed using multi - time correlations .
the model was recently generalized by toninelli in @xcite and for this generalization the stationary measure is known but the time correlations are unknown . in this note , we obtain algebraic and combinatorial proofs for the expression of the speed of growth from the prescribed dynamics . .
And you have already written the first three sentences of the full article: this note considers a stochastic growth model in the _ kpz anisotropic class _ in .
this model was introduced in @xcite and studied in depth for a specific initial condition , the case considered here .
this model describes the evolution of particles subject to an _ interlacing property_. the model can also be thought of as a two - dimensional _ stochastically growing interface _ , or as a _ random lozenge tiling model_. another tiling model which shares similar features of the dynamical perspective is _ domino tilings of the aztec diamond _ using _ the shuffling algorithm _ ; see @xcite . for.
Please generate the next two sentences of the article | the model considered in this paper , the evolution of the interface , under hydrodynamic scaling , grows deterministically according to a pde . at the microscopic level in the bulk ,
the specified boundary conditions of the system are _ forgotten _ : in the bulk of the system one sees an invariant measure which depends only on the normal direction of the macroscopic surface @xcite . from the lozenge tiling perspective , |
9,167 | Suppose that you have an abstract for a scientific paper: digital planetariums can provide a broader range of educational experiences than the more classical planetariums that use star - balls .
this is because of their ability to project images , content from current research and the 3d distribution of the stars and galaxies . while there are hundreds of planetariums in the country the reason that few of these are full digital is the cost . in collaboration with microsoft research ( msr )
we have developed a way to digitize existing planetariums for approximately $ 40,000 using software freely available .
we describe here how off the shelf equipment , together with msr s worldwide telescope client can provide a rich and truly interactive experience .
this will enable students and the public to pan though multi - wavelength full - sky scientific data sets , explore 3d visualizations of our solar system ( including trajectories of millions of minor planets ) , near - by stars , and the sdss galaxy catalog . .
And you have already written the first three sentences of the full article: the 8-meter diameter planetarium at the university of washington ( uw ) is primarily used for formal education as a part of our introductory astronomy classes .
graduate students also organize and coordinate informal educational presentations to k-12 students and astronomy clubs as well as programs for the general public . with an ms-8 star - ball projector and three vga projectors , the range of content of the presentations was limited by the lack of visualizations or at least constrained by the canned videos available . worldwide telescope ( wwt ) as a full dome digital projection system effectively eliminates the lack of visualizations , and with this software available to students and presenters every user can create their own tours and presentations ; removing the constraints of pre - made media .
we present our methods to digitize the uw planetarium on a tight budget i.e. , $ 40,000 total ( $ 10,000 for computers and $ 30,000 for projectors ) . in section [ proj ].
Please generate the next two sentences of the article | we discuss our choice of projectors and the need for conversion lenses and mounts , in section [ comp ] we explain the decisions involved in choosing the computer system . with the projectors and computers
nominally set up , we explain the alignment procedure in section [ alignm ] and in section [ conc ] we conclude by describing the expected integration of this digital dome within the educational curriculum . |
9,168 | Suppose that you have an abstract for a scientific paper: we report on the development of the first integrated mid - infrared , far - infrared and terahertz optical hall effect instrument , covering an ultra wide spectral range from 3 @xmath0 to 7000 @xmath0 ( 0.1210 thz or 0.4870 mev ) .
the instrument comprises four sub - systems , where the magneto - cryostat - transfer sub - system enables the usage of the magneto - cryostat sub - system with the mid - infrared ellipsometer sub - system , and the far - infrared / terahertz ellipsometer sub - system .
both ellipsometer sub - systems can be used as variable angle - of - incidence spectroscopic ellipsometers in reflection or transmission mode , and are equipped with multiple light sources and detectors .
the ellipsometer sub - systems are operated in polarizer - sample - rotating - analyzer configuration granting access to the upper left @xmath1 block of the normalized @xmath2 mueller matrix .
the closed cycle magneto - cryostat sub - system provides sample temperatures between room temperature and 1.4 k and magnetic fields up to 8 t , enabling the detection of transverse and longitudinal magnetic field - induced birefringence .
we discuss theoretical background and practical realization of the integrated mid - infrared , far - infrared and terahertz optical hall effect instrument , as well as acquisition of optical hall effect data and the corresponding model analysis procedures .
exemplarily , epitaxial graphene grown on 6__h__-sic , a tellurium doped bulk gaas sample and an algan / gan high electron mobility transistor structure are investigated .
the selected experimental datasets display the full spectral , magnetic field and temperature range of the instrument and demonstrate data analysis strategies .
effects from free charge carriers in two dimensional confinement and in a volume material , as well as quantum mechanical effects ( inter - landau - level transitions ) are observed and discussed exemplarily . .
And you have already written the first three sentences of the full article: the optical hall effect ( ohe ) is a physical phenomenon , which describes transverse and longitudinal magnetic field - induced birefringence , caused by the non - reciprocal magneto - optic response of electric charge carriers .
the term ohe is used in analogy to the classic , electrical hall effect@xcite , since the electrical hall effect and certain cases of ohe observation can be explained by extensions of the classic drude model for the transport of electrons in matter ( metals).@xcite for the ohe , drude s classic model is extended by a magnetic field and frequency dependency , describing the electron s momentum under the influence of the lorentz force . as a result
an antisymmetric contribution is added to the dielectric tensor @xmath3 , whose sign depends on the type of the free charge carrier ( electron , hole ) ..
Please generate the next two sentences of the article | the non - vanishing off - diagonal elements of the dielectric tensor reflect the magneto - optic birefringence , which lead to conversion of _
p_-polarized into _ |
9,169 | Suppose that you have an abstract for a scientific paper: utilizing an appropriate ansatz to the wave function , we reproduce the exact bound - state solutions of the radial schrdinger equation to various exactly solvable sextic anharmonic oscillator and confining perturbed coulomb models in @xmath0-dimensions . we show that the perturbed coulomb problem with eigenvalue @xmath1 can be transformed to a sextic anharmonic oscillator problem with eigenvalue @xmath2 we also check the explicit relevance of these two related problems in higher - space dimensions .
it is shown that exact solutions of these potentials exist when their coupling parameters with @xmath3 appearing in the wave equation satisfy certain constraints .
keywords : sextic anharmonic oscillator problem , perturbed coulomb problem , bound states , wave functions , schrdinger equation pacs number : 03.65.-w ; 03.65.fd ; 03.65.ge . .
And you have already written the first three sentences of the full article: the solution of the fundamental dynamical equations is an interesting phenomenon because of its importance in quantum - field theory , molecular physics , solid - state and statistical physics . to obtain the exact @xmath4-state solutions of the schrdinger equation ( se ) to various quantum mechanical problems are possible only for few potentials and hence approximation methods
are used to obtain their solutions . according to the schrdinger formulation of quantum mechanics , a total wave function provides implicitly all relevant information about the behaviour of a physical system .
hence if it is exactly solvable for a given potential , the wave function can describe such a system completely . until now.
Please generate the next two sentences of the article | , many efforts have been made to solve the stationary se with a sextic anharmonic oscillator and perturbed coulomb potentials in one to three dimensions through the hill determinant matrix method [ 1 - 4 ] .
the study of the se with these potentials provides us with insight into the physical problem under consideration . |
9,170 | Suppose that you have an abstract for a scientific paper: we study the photoionization properties of the c@xmath0 versus c@xmath1 molecule in a spherical jellium frame of density functional method .
two different approximations to the exchange - correlation ( xc ) functional are used : ( i ) the gunnerson - lundqvist parametrization [ phys .
rev .
b * 13 * , 4274 ( 1976 ) ] with an explicit correction for the electron self - interaction ( sic ) and ( ii ) a gradient - dependent augmentation of ( i ) by using the van leeuwen and baerends model potential [ phys .
rev .
a * 49 * , 2421 ( 1994 ) ] , in lieu of sic , to implicitly restore electrons asymptotic properties .
ground state results from the two schemes for both molecules show differences in the shapes of mean - field potentials and bound - level properties .
the choice of a xc scheme also significantly alters the dipole single - photoionization cross sections obtained by an _ abinitio _
method that incorporates linear - response dynamical correlations .
differences in the structures and ionization responses between c@xmath0 and c@xmath1 uncover the effect of molecular size on the underlying physics .
analysis indicates that the collective plasmon resonances with the gradient - based xc - option produce results noticeably closer to the experimental data available for c@xmath0 . .
And you have already written the first three sentences of the full article: fullerene molecules are a highly stable form of nanoscopic carbon allotrope that can exist at room temperature .
therefore , they are routinely attractive candidates for spectroscopic studies in understanding aspects of fundamental physics both in their vapor and condensed matter phases . technologically also , fullerenes hold the prospect of exciting applications in solid state quantum computations @xcite , improving the superconducting ability of materials @xcite , biomedical fields @xcite , contrast - enhancement research for magnetic resonance imaging ( mri ) , and improving organic photovoltaic devices @xcite . therefore , investigations of the response of these materials to radiations are valuable . one direction of these studies is to understand the collective response of fullerene electrons to relatively low - energy photons . in an infinite system like graphite , the incoming oscillatory electric field induces plane - wave type plasma oscillations in the electron cloud within the system s translational symmetry .
this can only quantize a surface plasmon quasi - particle , but not the longitudinal ( compressional ) volume plasmon , since light is a transverse wave ..
Please generate the next two sentences of the article | but when the medium has a boundary , the broken translational symmetry enables the plasma wave to reflect and induce other eigen modes of oscillations , including the volume quantization .
in particular , for finite systems with boundaries in all directions , such as fullerenes and metallic nanoclusters , photospectroscopy reveals multiple plasmons that were measured @xcite . |
9,171 | Suppose that you have an abstract for a scientific paper: * abstract * we consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of kerr type .
the perturbation theory , developed to calculate the temporal autocorrelation function of scattered wave , fails at short correlation times .
a self - consistent calculation shows that for nonlinearities exceeding a certain threshold value , the multiple - scattering speckle pattern becomes unstable and exhibits spontaneous fluctuations even in the absence of scatterer motion .
the instability is due to a distributed feedback in the system `` coherent wave + nonlinear disordered medium '' .
the feedback is provided by the multiple scattering .
the development of instability is independent of the sign of nonlinearity .
= 0 cm .
And you have already written the first three sentences of the full article: scattering of waves in disordered media has proved to be a nontrivial topic possessing intriguing and still not completely understood features.@xcite accordingly to the strength of disorder , one observes a variety of propagation regimes ranging from ballistic transport , through single scattering and wave diffusion , to the anderson localization . in this paper
we are interested in the regime of wave diffusion , corresponding to a relatively strong disorder , which is , however , still largely insufficient to bring the system to the localization transition ( @xmath0 , where @xmath1 is a wave number in the medium , and @xmath2 is a mean free path ) .
it is well - known , that multiple scattering of coherent wave in a disordered medium results in a complicated spatial intensity distribution @xmath3 known as a `` speckle pattern '' ..
Please generate the next two sentences of the article | the speckle pattern is highly irregular and appears random to the eye .
it is now well established that the speckle pattern exhibits large intensity fluctuations@xcite @xmath4 , originating from the interference of partial waves arriving at @xmath5 with completely randomized phases . here |
9,172 | Suppose that you have an abstract for a scientific paper: we describe the design and performance of the solar tower atmospheric cherenkov effect experiment detector in its initial configuration ( stacee-32 ) .
stacee is a new ground - based gamma ray detector using the atmospheric cherenkov technique . in stacee ,
the heliostats of a solar energy research array are used to collect and focus the cherenkov photons produced in gamma - ray induced air showers .
the large cherenkov photon collection area of stacee results in a gamma - ray energy threshold below that of previous detectors . .
And you have already written the first three sentences of the full article: this paper describes the initial configuration of stacee , a new ground - based gamma - ray detector . before addressing the detector itself
we provide a brief summary of the current experimental situation in gamma - ray astronomy and show the motivation for stacee and similar detectors .
gamma - ray astronomy has recently become a very exciting area of research . during the lifetime of nasa s compton gamma ray observatory ( cgro ) from april , 1991 to may , 2000 and following the construction of ground based detectors during the 1990 s , the field experienced rapid growth ..
Please generate the next two sentences of the article | the amount and quality of data increased and theoretical understanding of the related astrophysics improved greatly .
two instruments that were aboard the cgro are of special interest to high energy astrophysics . |
9,173 | Suppose that you have an abstract for a scientific paper: we find a new relation among right - handed dehn twists in the mapping class group of a @xmath0-holed torus for @xmath1 .
this relation induces an elliptic lefschetz pencil structure on the four - manifold @xmath2 @xmath3 with @xmath0 base points and twelve singular fibers . by blowing up the base points we get an elliptic lefschetz fibration on the complex elliptic surface @xmath4@xmath5 @xmath6 with twelve singular fibers and @xmath0 disjoint sections .
more importantly we can locate these @xmath0 sections in a kirby diagram of the induced elliptic lefschetz fibration .
the @xmath7-th power of our relation gives an explicit description for @xmath0 disjoint sections of the induced elliptic fibration on the complex elliptic surface @xmath8 for @xmath9 . .
And you have already written the first three sentences of the full article: it is well - known that two generic cubics @xmath10 and @xmath11 in @xmath3 intersect each other in nine points @xmath12 . by constructing the corresponding _ pencil _ of curves
@xmath13 \in \cpo \}\ ] ] one can define a map @xmath14 @xmath15 .
blowing up @xmath3 at @xmath16 one can extend @xmath17 to a lefschetz fibration @xmath18@xmath5 @xmath19@xmath20 whose generic fiber is an elliptic curve . our aim in this paper is to describe this construction in terms of differential topology ..
Please generate the next two sentences of the article | it turns out that many 4manifold topologists were curious about such a construction .
( for instance this was posed explicitly as a question in @xcite ) . |
9,174 | Suppose that you have an abstract for a scientific paper: we study the impact of central clearing of over - the - counter ( otc ) transactions on counterparty exposures in a market with otc transactions across several asset classes with heterogeneous characteristics . the impact of introducing a central counterparty ( ccp ) on expected interdealer exposure is determined by the tradeoff between multilateral netting across dealers on one hand and bilateral netting across asset classes on the other hand .
we find this tradeoff to be sensitive to assumptions on heterogeneity of asset classes in terms of ` riskyness ' of the asset class as well as correlation of exposures across asset classes .
in particular , while an analysis assuming independent , homogeneous exposures suggests that central clearing is efficient only if one has an unrealistically high number of participants , the opposite conclusion is reached if differences in riskyness and correlation across asset classes are realistically taken into account .
we argue that empirically plausible specifications of model parameters lead to the conclusion that central clearing does reduce interdealer exposures : the gain from multilateral netting in a ccp overweighs the loss of netting across asset classes in bilateral netting agreements .
when a ccp exists for interest rate derivatives , adding a ccp for credit derivatives is shown to decrease overall exposures .
these findings are shown to be robust to the statistical assumptions of the model as well as the choice of risk measure used to quantify exposures . .
And you have already written the first three sentences of the full article: over - the - counter ( otc ) derivatives represent a sizable fraction of financial transactions worldwide , encompassing a wide variety of contracts and asset classes . figure [ notionals_fig ]
depicts the development in the otc derivatives markets for different asset classes since 1998 .
although the increase in notionals has stopped since the peak of the financial crisis the overall growth is impressive . the contraction in some otc derivatives asset classes since the beginning of the crisis.
Please generate the next two sentences of the article | is clearly seen from table [ notionals.table ] , which shows gross notional values in different asset classes as of june 2007 and june 2010 .
[ c]lrr asset class & 2007 & 2010 + commodity & 8,255 & 3,273 + equity linked & 9,518 & 6,868 + foreign exchange & 57,604 & 62,933 + interest rate & 381,357 & 478,093 + credit derivatives & 51,095 & 31,416 + other & 78 & 72 + total & 507,907 & 582,655 + [ notionals.table ] most bilateral otc contracts involve exchange of collateral between counterparties , to mitigate counterparty risk . |
9,175 | Suppose that you have an abstract for a scientific paper: the hybrid n=1/n=2 supersymmetric model predicts scalar gluons ( sgluons ) as susy partners of the dirac gluino .
their strikingly distinct phenomenology at the cern large hadron collider is discussed . .
And you have already written the first three sentences of the full article: among many propositions for the physics beyond the standard model ( sm ) , supersymmetry ( susy ) is generally considered most elegant and respected . it can accommodate or explain some of the outstanding problems of the sm .
in fact this is the only mathematically consistent uv completion of the sm that stabilizes the gap between electroweak and planck scales .
it provides the gauge coupling unification , radiative electroweak symmetry breaking , a candidate for dark matter ( dm ) , offers new ideas on the matter - antimatter asymmetry etc ..
Please generate the next two sentences of the article | the simplest n=1 supersymmetric extension calls for each sm particle a sparticle that differs in spin by half a unit .
the lagrangian must be supplemented by susy breaking terms that keep unseen superpartners out of the current experimental reach while retaining all goodies of the model : renormalizability and perturbatively stable hierarchy of scales . with ever improving experimental constraints on susy breaking parameters , mainly from flavor and higgs physics , |
9,176 | Suppose that you have an abstract for a scientific paper: in this paper , we consider the problem of constellation design for a visible light communication ( vlc ) system using red / green / blue light - emitting diodes ( rgb led ) , and propose a method termed dc - informative joint color - frequency modulation ( dci - jcfm ) .
this method jointly utilizes available diversity resources including different optical wavelengths , multiple baseband subcarriers , and adaptive dc - bias .
constellation is designed in a high dimensional space , where the compact sphere packing advantage over lower dimensional counterparts is utilized . taking into account multiple practical illumination constraints ,
a non - convex optimization problem is formulated , seeking the least error rate with a fixed spectral efficiency .
the proposed scheme is compared with a decoupled scheme , where constellation is designed separately for each led .
notable gains for dci - jcfm are observed through simulations where balanced , unbalanced and very unbalanced color illuminations are considered . * constellation design , visible light communication , dc - informative , joint color - frequency , im / dd . * .
And you have already written the first three sentences of the full article: to satisfy the increasingly higher data rate demands , visible light communication ( vlc ) has drawn tremendous interest from both industry and academia as a promising complement to traditional radio frequency communication ( rfc ) that suffers from spectrum saturation @xcite .
the maturing of led manufacturing techniques during the recent decade largely boosts the trend of replacing traditional lighting systems with led alternatives for both indoor and outdoor illumination purposes , and the resulting infrastructures are ready for deployment of vlc .
it is a low - cost technology where one can use the simple intensity modulation and direct detection ( im / dd ) techniques ..
Please generate the next two sentences of the article | in addition , one can enjoy a bunch of additional advantages such as eye - safety , high security and causing no electromagnetic inference .
vlc is both unique from and similar to rfc . with regard to the uniqueness of vlc |
9,177 | Suppose that you have an abstract for a scientific paper: we report on the first far ir detection of h@xmath0d@xmath1 , using the _ infrared space observatory _ , in the line of sight toward sgr b2 in the galactic center .
the transition at @xmath2=126.853 @xmath3 m connecting the ground level of o - h@xmath0d@xmath1 , 1@xmath4 , with the the 2@xmath5 level at 113 k , is observed in absorption against the continuum emission of the cold dust of the source .
the line is broad , with a total absorption covering 350 km s@xmath6 , i.e. , similar to that observed in the fundamental transitions of h@xmath0o , oh and ch at @xmath7179 , 119 and 149 @xmath3 m respectively . for the physical conditions of the different absorbing clouds the h@xmath0d@xmath1 column density ranges from 2 to 5@xmath810@xmath9 @xmath10 , i.e. , near an order of magnitude below the upper limits obtained from ground based submillimeter telescopes .
the derived h@xmath0d@xmath1 abundance is of a few 10@xmath11 , which agrees with chemical models predictions for a gas at a kinetic temperature of @xmath1220 k. .
And you have already written the first three sentences of the full article: the h@xmath13 molecular ion is a key molecule for the gas phase chemistry in interstellar clouds ( herbst & kemplerer 1973 ; watson 1973 ) . produced by the fast reaction of h@xmath0 with h@xmath14 , it reacts with almost all neutral atoms and molecules , and thus it is the precursor of a large number of complex neutral and ionic molecular species . initially suggested to be present in molecular clouds by martin et al .
( 1961 ) , there is a long history behind the search for this crucial molecule . due to its lack of permanent dipole moment
, h@xmath13 must be observed in the near ir through its ro - vibrational transitions ( oka 1980 ) ..
Please generate the next two sentences of the article | the first searches only provided upper limits to the h@xmath13 column density ( geballe & oka 1989 ; black et al . ,
however , h@xmath13 has been finally detected toward gl2136 and the w33a clouds ( geballe & oka 1996 ) . |
9,178 | Suppose that you have an abstract for a scientific paper: we present a model of gravity based on spontaneous lorentz symmetry breaking .
we start from a model with spontaneously broken symmetries for a massless 2-tensor with a linear kinetic term and a nonderivative potential , which is shown to be equivalent to linearized general relativity , with the nambu - goldstone ( ng ) bosons playing the role of the gravitons .
we apply a bootstrap procedure to the model based on the principle of consistent coupling to the total energy energy - momentum tensor . demanding consistent application of the bootstrap to the potential term
severely restricts the form of the latter .
nevertheless , suitable potentials exists that permit stable vacua .
it is shown that the resulting model is equivalent , at low energy , to general relativity in a fixed gauge . .
And you have already written the first three sentences of the full article: masslessness often arises as a consequence of the existence of a symmetry . in quantum electrodynamics
the masslessness of the photon is normally attributed to gauge invariance , or symmetry under local changes of phase . in quantum chromodynamics ,
the theory of the strong interaction , masslessness of the gluons is likewise attributed to a gauge invariance , albeit a nonlinear one . in general relativity.
Please generate the next two sentences of the article | , the masslessness of gravitons can be traced to symmetry under active diffeomorphisms : no diffeomorphism - invariant mass term exists .
in some circumstances , however , there exists an alternative reason why a field might be massless . |
9,179 | Suppose that you have an abstract for a scientific paper: we study the narrow - line region ( nlr ) of six seyfert-1 and six seyfert-2 galaxies by means of spatially resolved optical spectroscopy and photoionization modelling . from spatially resolved spectral diagnostics
, we find a transition between the agn - excited nlr and the surrounding star - forming regions , allowing us to determine the nlr size independent of stellar contamination .
cloudy photoionization models show that the observed transition represents a true difference in ionization source and can not be explained by variations of physical parameters . the electron density and ionization parameter decrease with radius indicating that the nlr is photoionized by the central source only .
the velocity field suggests a disky nlr gas distribution . .
And you have already written the first three sentences of the full article: the narrow - line region ( nlr ) in active galactic nuclei ( agns ) is ideally suited to study the central region through its various emission lines .
it has the great advantage over the broad - line region ( blr ) to be spatially resolvable , at least for nearby agns . since the nlr is affected by various parameters such as the energy input from the central engine , the existence of a nuclear torus , radio jets , and star formation , it accesses a number of key questions of agn physics . [ ]
@xmath05007 ( hereafter [ ] ) narrow - band imaging is commonly used to study the nlrs of active galaxies , especially seyferts ( e.g. mulchaey et al ..
Please generate the next two sentences of the article | 1996a , falcke et al . 1998 ) . for qsos , this method was first applied by @xcite using an hst emission - line imaging survey of seven radio - quiet pg qsos with [email protected] . including seven seyferts
, they discovered a relation between nlr size and [ ] luminosity . |
9,180 | Suppose that you have an abstract for a scientific paper: in evolutionary game theory , an important measure of a mutant trait ( strategy ) is its ability to invade and take over an otherwise - monomorphic population .
typically , one quantifies the success of a mutant strategy via the probability that a randomly occurring mutant will fixate in the population . however ,
in a structured population , this fixation probability may depend on where the mutant arises .
moreover , the fixation probability is just one quantity by which one can measure the success of a mutant ; fixation _ time _ , for instance , is another .
we define a notion of homogeneity for evolutionary games that captures what it means for two single - mutant states , i.e. two configurations of a single mutant in an otherwise - monomorphic population , to be evolutionarily equivalent " in the sense that _ all _ measures of evolutionary success are the same for both configurations . using asymmetric games , we argue that the term homogeneous " should apply to the evolutionary process as a whole rather than to just the population structure . for evolutionary matrix games in graph - structured populations , we give precise conditions under which the resulting process is homogeneous .
finally , we show that asymmetric matrix games can be reduced to symmetric games if the population structure possesses a sufficient degree of symmetry . .
And you have already written the first three sentences of the full article: one of the most basic models of evolution in finite populations is the moran process @xcite . in the moran process , a population consisting of two types , a mutant type and a wild type , is continually updated via a birth - death process until only one type remains .
the mutant and wild types are distinguished by only their reproductive fitness , which is assumed to be an intrinsic property of a player .
a mutant type has fitness @xmath0 relative to the wild type ( whose fitness relative to itself is @xmath1 ) , and in each step of the process an individual is selected for reproduction with probability proportional to fitness ..
Please generate the next two sentences of the article | reproduction is clonal , and the offspring of a reproducing individual replaces another member of the population who is chosen for death uniformly at random .
eventually , this population will end up in one of the monomorphic absorbing states : all mutant type or all wild type . in this context , a fundamental metric of the success of the mutant type is its ability to invade and replace a population of wild - type individuals @xcite . in a population of size @xmath2 , |
9,181 | Suppose that you have an abstract for a scientific paper: we present flames / giraffe integral field spectroscopy of 30 galaxies in the massive cluster abell 1689 at z = 0.183 . conducting an analysis similar to that of atlas@xmath0 , we extend the baseline of the kinematic morphology - density relation by an order of magnitude in projected density and
show that it is possible to use existing instruments to identify slow and fast rotators beyond the local universe .
we find @xmath1 slow rotators with a distribution in magnitude similar to those in the virgo cluster .
the overall slow rotator fraction of our abell 1689 sample is @xmath2 , the same as in virgo using our selection criteria .
this suggests that the fraction of slow rotators in a cluster is not strongly dependent on its density .
however , within abell 1689 , we find that the fraction of slow rotators increases towards the centre , as was also found in the virgo cluster .
[ firstpage ] galaxies : kinematics and dynamics , galaxies : clusters : individual : abell 1689 .
And you have already written the first three sentences of the full article: early type galaxies ( etgs ) , despite having masses and luminosities that span several orders of magnitude , obey a number of tight phenomenological laws . these , collectively known as `` scaling relations '' , include the color - magnitude diagram ( cmd : * ? ? ?
* ; * ? ? ?
* ; * ? ? ?.
Please generate the next two sentences of the article | * ; * ? ? ?
* ) , the color-@xmath3 and @xmath4 @xcite relations and the fundamental plane @xcite . with their remarkably small scatter , |
9,182 | Suppose that you have an abstract for a scientific paper: stabilizing a nulling interferometer at a nanometric level is the key issue to obtain deep null depths .
the persee breadboard has been designed to study and optimize the operation of a cophased nulling bench in the most realistic disturbing environment of a space mission .
this presentation focuses on the current results of the persee bench . in terms of metrology
, we cophased at 0.33 nm rms for the piston and 80 mas rms for the tip / tilt ( 0.14% of the airy disk ) . a linear quadratic gaussian ( lqg ) control coupled with an unsupervised vibration identification allows us to maintain that level of correction , even with characteristic vibrations of nulling interferometry space missions .
these performances , with an accurate design and alignment of the bench , currently lead to a polychromatic unpolarised null depth of @xmath0 stabilized at @xmath1 on the @xmath2 $ ] spectral band ( 37% bandwidth ) . .
And you have already written the first three sentences of the full article: ir spectrometry is a powerful method to characterize the hundreds of exoplanets discovered by indirect methods , and ultimately to search for life on telluric ones , as it allows to evidence atmospheric signatures of interest ( h@xmath3o , co@xmath3 , ch@xmath4 , ... ) boosted by the thermal emission of the planet .
the main challenge is to isolate the planet from its parent nearby star ; one of the very few possible methods is spaceborne nulling interferometry , allowing implementing very efficient coronagraphs at the diffraction limit . within this framework ,
several space projects such as darwin@xcite , tpf - i@xcite , fksi@xcite or pegase@xcite , have been proposed in the past years ..
Please generate the next two sentences of the article | most of them are based on a free - flying concept to create hectometric pupils with an acceptable launch mass .
but the price to pay is to very precisely position and stabilize the spacecrafts relatively to each other and also with respect to an inertial direction , in order to achieve a deep and stable extinction of the star . |
9,183 | Suppose that you have an abstract for a scientific paper: we summarize some predictions from the model of supermassive object with magnetic monopoles which match up with recent astronomical observations quantitatively . they may be the signals for existence of magnetic monopoles in the supermassive objects , such as one at the galactic center . .
And you have already written the first three sentences of the full article: most of physicists believe that the existence of magnetic monopoles had been ruled out by experiments .
however , experiments only indicated that the flux of magnetic monopoles on the earth is too low to be observed . in the primordial universe ,
the electromagnetic interaction between magnetic monopoles and plasma is so strong such that magnetic monopoles might store up in the center of quasars and active galactic nuclei ( agn ) during the collapsing process of the original giant nebulae , including at the collapsed core of the galactic center ( gc ) . due to the rubakov - callan ( rc ) effect@xcite.
Please generate the next two sentences of the article | , magnetic monopoles may catalyze nucleon decay and is invoked as the energy source of quasars and agn .
the model of supermassive object with magnetic monopoles ( smomm ) @xcite , presented by one ( qp ) of the authors , gave five predictions , some of which match up with the recent astronomical observations quantitatively . |
9,184 | Suppose that you have an abstract for a scientific paper: we have performed deep imaging of a diverse sample of 26 low surface brightness galaxies ( lsbgs ) in the optical and the near - infrared . using stellar population synthesis models , we find that it is possible to place constraints on the ratio of young to old stars ( which we parameterise in terms of the average age of the galaxy ) , as well as the metallicity of the galaxy , using optical and near - infrared colours .
lsbgs have a wide range of morphologies and stellar populations , ranging from older , high metallicity earlier types to much younger and lower metallicity late type galaxies . despite this wide range of star formation histories
, we find that colour gradients are common in lsbgs .
these are most naturally interpreted as gradients in mean stellar age , with the outer regions of lsbgs having younger ages than their inner regions . in an attempt to understand what drives the differences in lsbg stellar populations , we compare lsbg average ages and metallicities with their physical parameters .
strong correlations are seen between a lsbg s star formation history and its @xmath0 band surface brightness , @xmath0 band absolute magnitude and gas fraction .
these correlations are consistent with a scenario in which the star formation history of a lsbg primarily correlates with its surface density and its metallicity correlates both with its mass and surface density .
galaxies : spiral galaxies : stellar content galaxies : evolution galaxies : general galaxies : fundamental parameters galaxies : photometry .
And you have already written the first three sentences of the full article: there has been much recent debate on the star formation histories ( sfhs ) of low surface brightness disc galaxies ( lsbgs ; galaxies with @xmath1 band central surface brightnesses fainter than 22.5 magarcsec@xmath2 ) .
the best studied lsbgs are blue in the optical and the near - infrared ( near - ir ) @xcite , indicating a young mean stellar age and/or low metallicity .
their measured region metallicities are low , at around or below @xmath3 solar abundance @xcite ..
Please generate the next two sentences of the article | morphologically , the best studied lsbgs have discs , but little spiral structure @xcite . the current massive star formation rates ( sfrs ) in lsbgs are an order of magnitude lower than those of high surface brightness ( hsb ) galaxies @xcite .
observations show that lsbgs have high gas mass fractions , sometimes even approaching unity @xcite . as |
9,185 | Suppose that you have an abstract for a scientific paper: this contribution summarizes the main experimental results presented at the 2009 quark matter conference concerning single and dilepton production in proton and heavy ion collisions at high energy .
the dilepton invariant mass spectrum has been measured over a range that extends from the @xmath0 mass to the @xmath1 mass , and for various collision energies at sps , fermilab , hera and rhic .
this paper focuses on the various contributions ( photons , low mass vector mesons , open and hidden heavy flavors ) to this spectrum and discuss their implications on our understanding of the matter formed in heavy ion collisions . .
And you have already written the first three sentences of the full article: single and dilepton probes in heavy ion collisions are of particular interest since such probes , once produced , are largely unaffected by the surrounding qcd medium .
they carry valuable information on the particle from which they originate and allow one to assess the properties of the medium formed in the early instants of the collision .
the following contributions to the dilepton invariant mass spectrum are discussed here , together with what one might learn from their measurement about the properties of the medium formed in the collision : * low mass dileptons originating from vector meson leptonic decay ( @xmath2 , @xmath3 and @xmath4 ) provide insight on the properties of these mesons in the high temperature expanding fireball produced immediately after the collision , where chiral symmetry may be ( at least partially ) restored @xcite ; * a significant fraction of the virtual and direct photons produced at low @xmath5 ( @xmath6 gev / c ) in heavy ion collisions originates from the thermal black - body radiation of the created fireball @xcite ..
Please generate the next two sentences of the article | measuring these photons therefore allows one to quantify the temperature of the fireball ; * open heavy flavors , because of their high mass , allow one to study in - medium energy loss mechanisms in addition to what can be learned from light quarks @xcite ; * heavy quarkonia are of interest because of additional mechanisms that are predicted to occur in the presence of a qgp and that would affect the production of these bound states @xcite .
fig . [ low_mass_vector_mesons ] ( left ) shows the correlated dimuons invariant mass distribution at the @xmath2 vacuum mass , measured by the na60 experiment in semi - central in+in collisions @xcite . |
9,186 | Suppose that you have an abstract for a scientific paper: the problem of weakly correlated electrons on a square lattice is formulated in terms of one - loop renormalization group .
starting from the action for the entire brillouin zone ( and not with a low - energy effective action ) we reduce successively the cutoff @xmath0 about the fermi surface and follow the renormalization of the coupling @xmath1 as a function of three energy - momenta .
we calculate the intrinsic scale @xmath2 where the renormalization group flow crosses over from the regime ( @xmath3 ) where the electron - electron ( e - e ) and electron - hole ( e - h ) terms are equally important to the regime ( @xmath4 ) where only the e - e term plays a role . in the low energy regime
only the pairing interaction @xmath5 is marginally relevant , containing contributions from all renormalization group steps of the regime @xmath3 .
after diagonalization of @xmath6 , we identify its most attractive eigenvalue @xmath7 . at low filling
, @xmath7 corresponds to the @xmath8 representation ( @xmath9 symmetry ) , while near half filling the strongest attraction occurs in the @xmath10 representation ( @xmath11 symmetry ) . in the direction of the van hove singularities , the order parameter shows peaks with increasing strength as one approaches half filling . using the form of pairing and the structure of the renormalization group equations in the low energy regime ,
we give our interpretation of arpes experiments trying to determine the symmetry of the order parameter in the bi2212 high-@xmath12 compound . .
And you have already written the first three sentences of the full article: an immense number of recent experiments on high @xmath13 superconductors aims at a determination of the form of the bcs gap function in momentum space.@xcite josephson junction experiments,@xcite measurements of the london penetration depth,@xcite and of the cu nmr relaxation rate @xcite are consistent with a @xmath11-gap . particularly interesting
are the arpes data which provide rather precise information about the detailed angular dependence of the amplitude of the gap function .
the experiments on the bi2212 compound show that the order parameter is maximal along the @xmath14 direction @xcite and that its amplitude in the @xmath15 direction seems to attain a nonzero value at a new critical temperature below @xmath13 ..
Please generate the next two sentences of the article | @xcite the @xmath16 symmetry of the gap function is generally considered to be a sign of a pairing interaction of electronic origin , implying the absence of the standard phononic mechanism for superconductivity .
the idea of a superconducting state induced by fluctuations of purely electronic origin in systems of electrons with coulomb repulsion is originally due to kohn and luttinger @xcite for the case of the three dimensional electron gas . |
9,187 | Suppose that you have an abstract for a scientific paper: the stis / ccd camera on the _ hubble space telescope ( hst ) _ was used to take deep optical images near the k2v main - sequence star @xmath0 eridani in an attempt to find an optical counterpart of the dust ring previously imaged by sub - mm observations .
upper limits for the optical brightness of the dust ring are determined and discussed in the context of the scattered starlight expected from plausible dust models .
we find that , even if the dust is smoothly distributed in symmetrical rings , the optical surface brightness of the dust , as measured with the _
hst_/stis ccd clear aperture at 55 au from the star , can not be brighter than about 25 stmag/``@xmath1 .
this upper limit excludes some solid grain models for the dust ring that can fit the ir and sub - mm data .
magnitudes and positions for @xmath259 discrete objects between 12.5 '' to 58 " from @xmath0 eri are reported . most if not all of these objects are likely to be background stars and galaxies .
1based on observations made with the nasa / esa hubble space telescope , obtained at the space telescope science institute , which is operated by the association of universities for research in astronomy , inc .
, under nasa contract nas 5 - 26555 .
these observations are associated with proposal go-09037 .
2also the space telescope science institute , and the institute for astrophysics and computational science at the catholic university of america .
3also eureka scientific , 2452 delmer street , suite 100 , oakland , ca 94602 - 3017 4member of space telescope imaging spectrograph investigation definition team .
And you have already written the first three sentences of the full article: a substantial fraction ( @xmath3% ) of main - sequence stars show evidence for excess ir or sub - mm flux due to thermal emission from dust located at distances of 30 au or more from the stars ; i.e. , locations comparable to that of the kuiper belt in our own solar system .
this was first discovered using iras observations ( e.g. , aumann et al . 1984 ; 1985 ; gillett & aumann 1983 ) , and subsequently , observations with the james clarke maxwell telescope s submillimeter common - user bolometer array ( jcmt / scuba ) have directly imaged the dust distribution in a few of these systems ( holland et al .
1998 ) , including @xmath0 eri ( greaves et al 1998 ) ..
Please generate the next two sentences of the article | @xmath0 eridani is a k2v main - sequence star at a distance of about 3.2 pc .
it is believed to be a relatively young system ( @xmath4 gyr ; song et al . |
9,188 | Suppose that you have an abstract for a scientific paper: recently , there are two hints arising from physics beyond the standard model .
one is a possible energy loss mechanism due to emission of very weakly interacting light particles from white dwarf stars , with a coupling strength @xmath0 , and another is the high energy positrons observed by the pamela satellite experiment .
we construct a supersymmetric flipped - su(5 ) model , 1 with appropriate additional symmetries , [ u(1)@xmath1_{\rm gauge}\times$][u(1)@xmath2u(1)@xmath3_{\rm global}\times z_2 $ ] , such that these are explained by a very light _ electrophilic _
axion of mass 0.5 mev from the spontaneously broken u(1)@xmath4 and two component cold dark matters from @xmath5 parity .
we show that in the flipped - su(5 ) there exists a basic mechanism for allowing excess positrons through the charged su(5 ) singlet leptons , but not allowing anti - proton excess due to the absence of the su(5 ) singlet quarks .
we show the discovery potential of the charged su(5 ) singlet @xmath6 at the lhc experiments by observing the electron and positron spectrum . with these symmetries , we also comment on the mass hierarchy between the top and bottom quarks . .
And you have already written the first three sentences of the full article: the most looked - for particles on earth at the present time are axions @xcite and weakly interacting massive particles(wimps ) @xcite .
recently , hints on these particles have been reported from outer space sources .
the 10 year old integral data @xcite gives the 511 kev line ..
Please generate the next two sentences of the article | the white dwarf cooling has been suggested by the emission of very weakly interacting light particles(vwlp ) ( mass less than @xmath7 ev ) with a very small coupling strength to electron ( @xmath0 ) @xcite . at present , this white dwarf bound can be considered just as an upper bound , but in this paper we adopt a bold assumption that their best fit corresponds to the existence of a vwlp .
more recently , the remarkable observation of high energy positron excess in the satellite pamela data @xcite hints heavy ( 100 gev 10 tev ) cold dark matter(cdm ) particles @xcite . |
9,189 | Suppose that you have an abstract for a scientific paper: the main result of the paper is a new representation of the weyl lagrangian ( massless dirac lagrangian ) . as the dynamical variable we use the coframe , i.e. an orthonormal tetrad of covector fields .
we write down a simple lagrangian wedge product of axial torsion with a lightlike element of the coframe and show that variation of the resulting action with respect to the coframe produces the weyl equation .
the advantage of our approach is that it does not require the use of spinors , pauli matrices or covariant differentiation .
the only geometric concepts we use are those of a metric , differential form , wedge product and exterior derivative .
our result assigns a variational meaning to the tetrad representation of the weyl equation suggested by j. b. griffiths and r. a. newing . .
And you have already written the first three sentences of the full article: throughout this paper we work on a 4-manifold @xmath0 equipped with prescribed lorentzian metric @xmath1 .
the accepted mathematical model for a neutrino field is the following linear partial differential equation on @xmath0 know as the _ weyl equation _ : @xmath2 the corresponding lagrangian is @xmath3 here @xmath4 , @xmath5 , are pauli matrices , @xmath6 is the unknown spinor field , and @xmath7 is the covariant derivative with respect to the levi - civita connection : @xmath8 where @xmath9 are christoffel symbols uniquely determined by the metric .
the purpose of our paper is to give an alternative representation of the weyl equation ( [ weyl s equation ] ) and the weyl lagrangian ( [ weyl s lagrangian ] ) . to this end , we follow @xcite in introducing instead of the spinor field a different unknown the so - called _.
Please generate the next two sentences of the article | a coframe is a quartet of real covector fields @xmath10 , @xmath11 , satisfying the constraint @xmath12 where @xmath13 . in other words , the coframe is a field of orthonormal bases with orthonormality understood in the lorentzian sense .
we define an affine connection and corresponding covariant derivative @xmath14 from the conditions @xmath15 ) read @xmath16 giving a system of linear algebraic equations for the unknown connection coefficients @xmath17 . |
9,190 | Suppose that you have an abstract for a scientific paper: we observed the first known very high energy ( vhe ) @xmath0-ray emitting unidentified source , tev j2032 + 4130 , for 94 hours with the magic telescope .
the source was detected with a significance of 5.6@xmath1 .
the flux , position , and angular extension are compatible with the previous ones measured by the hegra telescope system five years ago
. the integral flux amounts to ( [email protected]@xmath30.35@xmath4)@xmath510@xmath6 ph @xmath7 s@xmath8 above 1 tev .
the source energy spectrum , obtained with the lowest energy threshold to date , is compatible with a single power law with a hard photon index of @[email protected]@xmath100.2@xmath11 . .
And you have already written the first three sentences of the full article: the tev source j2032 + 4130 ( aharonian et al . 2002 ) was the first unidentified very high energy ( vhe ) @xmath0-ray source , and also the first discovered extended tev source , likely to be galactic .
intensive observational campaigns at different wavelengths have been carried out on tev j2032 + 4130 .
butt et al ..
Please generate the next two sentences of the article | ( 2003 ) presented an analysis of the co , hi , and infrared emissions , together with first observations by _ chandra _ ( 5 ksec ) and a reanalysis of vla data .
these observations showed that the tev source region is positionally coincident with an outlying group of stars ( from the cygnus ob2 core ) , although they failed to identify a counterpart . |
9,191 | Suppose that you have an abstract for a scientific paper: we introduce and implement two novel ideas for modeling lensed quasars . the first idea is to require different lenses to agree about @xmath0 .
this means that some models for one lens can be ruled out by data on a different lens .
we explain using two worked examples .
one example models 1115 + 080 , 1608 + 656 ( time - delay quads ) and 1933 + 503 ( a prospective time - delay system ) all together , yielding time - delay predictions for the third lens and a 90%-confidence estimate of @xmath1 gyr ( @xmath2 ) assuming @xmath3 .
the other example models the time - delay doubles 1520 + 530 , 1600 + 434 , 1830 - 211 , and 2149 - 275 , which gives @xmath4 gyr ( @xmath5 ) .
our second idea is to write the whole modeling software as a highly interactive java applet , which can be used both for coarse - grained results inside a browser and for fine - grained results on a workstation .
several obstacles come up in trying to implement a numerically - intensive method thus , but we overcome them . .
And you have already written the first three sentences of the full article: some aspects of modeling lensed quasars are much as they were just after the discovery of the first double quasar 0957 + 561 . in one of the earliest lens - modeling papers , @xcite are concerned with some now - very - familiar issues : the effect on image positions of both the main lensing galaxy and other galaxies , the time delays predicted by the models , the non - uniqueness of the models despite the adequacy of the data , and the desirability of supplementary data about the lens , such as velocity dispersions or x - rays .
but other aspects of the subject these days would have been unimaginable in 1981 .
the first double quasar has been joined by dozens of others : the castles survey compilation @xcite currently lists 76 secure multiple - image galaxy - lens systems , with image positions measured to the mas level , even more precisely if there are compact radio sources . and.
Please generate the next two sentences of the article | the time delay for 0957 + 561 , for which young et al.s preliminary estimate was about 5 years , is now measured as @xmath6 @xcite , along with time - delay measurements for eight other systems .
these excellent data demand new , more automatic , and more portable software tools for modeling the lenses . |
9,192 | Suppose that you have an abstract for a scientific paper: quiescent prominences are thin slabs of cold , dense plasma embedded in the much hotter and rarer solar corona .
although their global shape is rather irregular , they are often characterised by an internal structure consisting of a large number of thin , parallel threads piled together .
prominences often display periodic disturbances mostly observed in the doppler displacement of spectral lines and with an amplitude typically of the order of or smaller than 23 km s@xmath0 , a value which seems to be much smaller than the characteristic speeds of the prominence plasma ( namely the alfvn and sound velocities ) .
two particular features of these small amplitude prominence oscillations is that they seem to damp in a few periods and that they seem not to affect the whole prominence structure .
in addition , in high spatial resolution observations , in which threads can be discerned , small amplitude oscillations appear to be clearly associated to these fine structure constituents .
prominence seismology tries to bring together the results from these observations ( e.g. periods , wavelengths , damping times ) and their theoretical modelling ( by means of the magnetohydrodynamic theory ) to gain insight into physical properties of prominences that can not be derived from direct observation . in this paper
we discuss works that have not been described in previous reviews , namely the first seismological application to solar prominences and theoretical advances on the attenuation of prominence oscillations . .
And you have already written the first three sentences of the full article: the solar corona is often populated by peculiar objects , dense clouds of cold plasma inexplicably floating tens of thousands of kilometres above the photosphere .
such objects are routinely seen during solar eclipses , when they can be easily distinguished by their red glow , but they can also be unveiled with the help of filters , such as h@xmath1 , devised to observe the chromosphere ( fig .
[ fig1 ] ) . to put it in simple words , these objects ( usually called prominences or filaments ) are like chunks of chromospheric gas defying the downward pull of gravity and staying in a place higher than the one that apparently corresponds to their large density ..
Please generate the next two sentences of the article | this is not the only enigma around solar prominences .
in contrast with the mk temperature of the surrounding corona , prominences remain at a comparatively cool 10,000 k , which prompts one to ask what prevents the mechanisms that heat the corona from also raising the temperature of prominences and consequently dispersing them . other pieces of the prominence puzzle concern their beginning and end : first , one may wonder not just how prominences form but also why they are born in an adverse environment . |
9,193 | Suppose that you have an abstract for a scientific paper: we propose a new method for determination of the rotation velocity of the galactic spiral density waves , correspondingly , the corotation radius , @xmath0 , in our galaxy by means of statistical analysis of radial oxygen distribution in the galactic disc derived over cepheids . the corotation resonance happens to be located at @xmath1 kpc , depending on the rate of gas infall on to the galactic disc , the statistical error being @xmath2 kpc .
simultaneously , the constant for the rate of oxygen synthesis in the galactic disc was determined .
we also argue in favour of a very short time - scale formation of the galactic disc , namely : @xmath3 gyr .
this scenario enables to solve the problem of the lack of intergalactic gas infall .
[ firstpage ] galaxy : fundamental parameters galaxy : abundances galaxies : spiral galaxies : star formation . .
And you have already written the first three sentences of the full article: it is recognized that the corotation resonance where the rotation velocities of galactic matter and density waves , responsible for spiral arms coincide , plays an important role in the galactic evolution and the value of the corotation radius is one of the fundamental galactic parameters . in literature
one can find several methods of this quantity deriving in our galaxy , for instance , by means of analysis of arms geometry , stellar or open clusters kinematics , hi and hii emissions ( e.g. , lin et al .
1969 ; marochnik et al ..
Please generate the next two sentences of the article | 1972 ; mishurov & zenina 1999 ; lpine et al .
2001 ; fernandez et al . 2001 ; dias & lpine 2005 , etc . ) . in the present paper , |
9,194 | Suppose that you have an abstract for a scientific paper: following the recent theoretical interpretation of grb 090618 and grb 101023 , we here interpret grb 970828 in terms of a double episode emission : the first episode , observed in the first 40 s of the emission , is interpreted as the proto - black - hole emission ; the second episode , observed after t@xmath0 + 50 s , as a canonical gamma ray burst .
the transition between the two episodes marks the black hole formation .
the characteristics of the real grb , in the second episode , are an energy of @xmath1 erg , a baryon load of @xmath2 and a bulk lorentz factor at transparency of @xmath3 .
the clear analogy with grb 090618 would require also in grb 970828 the presence of a possible supernova .
we also infer that the grb exploded in an environment with a large average particle density @xmath4 part/@xmath5 and dense clouds characterized by typical dimensions of @xmath6 cm and @xmath7 .
such an environment is in line with the observed large column density absorption , which might have darkened both the supernova emission and the grb optical afterglow . .
And you have already written the first three sentences of the full article: grb 970828 is one of the first grbs with an observed afterglow @xcite and a determined redshift of @xmath8=0.9578 from the identification of its host galaxy @xcite .
this source is still presenting today , after 15 years from its observations , an extremely rich problematic in the identification of its astrophysical nature .
the x - ray afterglow was discovered by the asca satellite 1.17 days after the grb trigger @xcite and the data showed the presence of a feature around @xmath9 5 kev , maybe associated to a radiative recombination edge of a h- or he - like ionized iron @xcite ..
Please generate the next two sentences of the article | particularly interesting was also a variable and large intrinsic absorption column which was found from the asca : the absence of an optical afterglow @xcite , the large intrinsic absorption column detected in the x - ray data @xcite and the contemporary detection in radio - wavelengths of the grb afterglow , imply a very large value for the circum - burst medium ( cbm ) , this variable absorption might be an indication of a strong inhomogeneous cbm distribution .
@xcite described the presence of an evolving thermal component in the first 40 s of the emission of grb 970828 , as observed by the batse detector on board the compton gamma ray telescope @xcite . |
9,195 | Suppose that you have an abstract for a scientific paper: condensates of atoms with spins can have vortices of several types ; these are related to the symmetry group of the atoms ground state .
we discuss how , when a condensate is placed in a small magnetic field that breaks the spin symmetry , these vortices may form bound states . using symmetry classification of vortex - charge and rough estimates for vortex interactions , one can show that some configurations that are stable at zero temperature can decay at finite temperatures by crossing over energy barriers .
our focus is cyclic spin 2 condensates , which have tetrahedral symmetry . in an image of a nematic liquid crystal by polarized light
, one can identify topological defects of various topological charges ( see ref .
@xcite ) .
bose condensates ( see the books@xcite ) are starting to provide another context for studying topological defects : in the texture formed by the phase _ and _ spin of a spinor condensate@xcite .
( see also @xcite for reviews of the theory and experimental techniques being applied to spinor condensates . )
a topological defect in the _ phase _ _ of a superfluid _ is a quantized vortex .
the discontinuity in the phase as the defect is encircled must be @xmath0 for an integer @xmath1 , and the circulation of the vortex is then @xmath2 . in a single - component superfluid , multiply quantized vortices ( @xmath3 ) are usually not stable .
the widely known explanation is that the energy of a vortex is proportional to @xmath4 .
thus a doubly quantized vortex ( @xmath5 ) can lower its energy by splitting into two singly quantized vortices .
similar arguments can be formulated for multicomponent condensates , but we will find that some vortices in these condensates can be very long - lived in spite of having large energies .
our predictions are about condensates of atoms with spin in which the rotational symmetry has been weakly disrupted by a small parameter @xmath6 , such as the interaction between the spins and the magnetic field .
( we focus on the _....
And you have already written the first three sentences of the full article: vortices are simplest to understand for an interaction energy that has a single manifold , @xmath85 , of ground states and no hierarchy . the order parameter must move into @xmath85 far away from any spin texture .
vortices are classified by the topology of the circuit traced out in @xmath85 by the order parameter on a large circle containing a vortex or set of vortices .
although there are many ways to add wiggles to a given circuit , only the topological structure is important , leading to a discrete set of possible vortex charges ..
Please generate the next two sentences of the article | [ fig : iron ] shows how a circuit may be tangled with holes in the space @xmath85 .
as a vortex evolves , such a circuit can evolve only into other circuits that are tangled in the same way ; thus the vortex charge is conserved . |
9,196 | Suppose that you have an abstract for a scientific paper: we study the spin polarization and its associated spin - hall current due to electric - dipole - induced spin resonance in disordered two - dimensional electron systems .
we show that the disorder induced damping of the resonant spin polarization can be strongly reduced by an optimal field configuration that exploits the interference between rashba and dresselhaus spin - orbit interaction .
this leads to a striking enhancement of the spin susceptibility while the spin - hall current vanishes at the same time .
we give an interpretation of the spin current in geometrical terms which are associated with the trajectories the polarization describes in spin space .
the ability to coherently control the spin of charge carriers in semiconductor nanostructures is the main focus of spintronics@xcite .
band - structure and confinement effects in these systems lead to a strong spin - orbit interaction ( soi ) offering the possibility to efficiently access the charge carrier spin via the control of its orbital motion@xcite .
a versatile and efficient scheme of spin control is electric dipole induced spin resonance ( edsr)@xcite where electric radio frequency ( rf ) fields give rise to internal fields coupling to the spin .
choosing an adequate configuration of the electric rf fields and a static magnetic field defining a quantization axis for the spin , arbitrary spin rotations can be realized .
this is analogous to standard paramagnetic spin resonance techniques , has the advantage , however , that it can be integrated in gated nanostructures thereby avoiding magnetic rf coils . in a two - dimensional electron gas ( 2deg ) with pure rashba
soi the amount of spin polarization which can be achieved by edsr is severely limited by disorder@xcite .
similar limitations are found for pure dresselhaus soi .
however , if both dresselhaus and rashba soi are present interference between the two soi mechanisms can occur and qualitatively new behavior emerges , such as anisotropy in spin....
And you have already written the first three sentences of the full article: for @xmath166 , @xmath167 , and @xmath168 the functions @xmath48 and @xmath47 are given by @xmath169 \
, , \end{aligned}\ ] ] @xmath170 \ , , \end{aligned}\ ] ] @xmath171 \ , , \end{aligned}\ ] ] @xmath172 \ , , \end{aligned}\ ] ] and @xmath173 and @xmath174 ..
Please generate the next two sentences of the article | |
9,197 | Suppose that you have an abstract for a scientific paper: the uv / ir mixing in the @xmath0 model on a non - commutative ( nc ) space leads to new predictions in perturbation theory , including hartree
fock type approximations . among them
there is a changed phase diagram and an unusual behavior of the correlation functions . in particular
this mixing leads to a deformation of the dispersion relation .
we present numerical results for these effects in @xmath1 with two nc coordinates . .
And you have already written the first three sentences of the full article: field theories defined on a nc geometry are highly fashionable , in particular because they arise from a low energy limit of string theory @xcite
. a nc space may be defined by the non commutativity of some of its coordinates @xmath2 = i\theta_{\mu\nu } \,\overset{\text{2d}}{=}\ , i \theta \epsilon_{\mu \nu}\,.\ ] ] for a review of nc field theories , see ref .
the extension of actions of commutative field theories to their nc counterparts can be realized by replacing all products between fields by the _ star product _ @xmath3 in the nc @xmath0 model this replacement leads to the action @xmath4\,,\nonumber\ ] ] where only the interaction term requires the star product . in perturbation.
Please generate the next two sentences of the article | theory the one loop contribution to the 1 pi two point function splits into two parts coming from the planar and the non planar graphs .
the planar terms are proportional to their ( uv divergent ) commutative counterparts @xcite . in the case of the non planar graphs the momentum cut off |
9,198 | Suppose that you have an abstract for a scientific paper: in this paper we propose a new inexact dual decomposition algorithm for solving separable convex optimization problems .
this algorithm is a combination of three techniques : dual lagrangian decomposition , smoothing and excessive gap .
the algorithm requires only one primal step and two dual steps at each iteration and allows one to solve the subproblem of each component inexactly and in parallel .
moreover , the algorithmic parameters are updated automatically without any tuning strategy as in augmented lagrangian approaches .
we analyze the convergence of the algorithm and estimate its @xmath0 worst - case complexity .
numerical examples are implemented to verify the theoretical results .
example.eps gsave newpath 20 20 moveto 20 220 lineto 220 220 lineto 220 20 lineto closepath 2 setlinewidth gsave .4 setgray fill grestore stroke grestore .
And you have already written the first three sentences of the full article: many practical optimization problems must be addressed within the framework of large - scale structured convex optimization and need to be solved in a parallel and distributed manner .
such problems may appear in many fields of science and engineering : e.g. graph theory , networks , transportation , distributed model predictive control , distributed estimation and multistage stochastic optimization , see e.g. @xcite and the references quoted therein .
solving large - scale optimization problems is still a challenge in many applications @xcite due to the limitations of computational devices and computer systems ..
Please generate the next two sentences of the article | recently , thanks to the development of parallel and distributed computer systems , many large - scale problems have been solved by using the framework of decomposition .
however , methods and algorithms for solving this type of problems , which can be performed in a parallel or distributed manner , are still limited @xcite . in this paper |
9,199 | Suppose that you have an abstract for a scientific paper: along the line of thoughts of berry and robnik@xcite , the limiting gap distribution function of classically integrable quantum systems is derived in the limit of infinitely many independent components .
the limiting gap distribution function is characterized by a single monotonically increasing function @xmath0 of the level spacing @xmath1 , and the corresponding level spacing distribution is classified into three cases : ( i ) poissonian if @xmath2 , ( ii ) poissonian for large @xmath1 , but possibly not for small @xmath1 if @xmath3 , and ( iii ) sub - poissonian if @xmath4 .
this implies that even when the energy - level distributions of individual components are statistically independent , non - poissonian level spacing distributions are possible . .
And you have already written the first three sentences of the full article: an important property of quantum - classical correspondence appears in the statistical property of energy levels of bounded quantum systems in the semiclassical limit .
universal behaviors are found in the statistics of _ unfolded _ energy levels at a given interval@xcite , which are the sequence of numbers uniquely determined by the energy levels using the mean level density obtained from the thomas - fermi rule@xcite .
it is widely known that , for quantum systems whose classical counterparts are integrable ( those systems will be referred to as classically integrable systems ) , the distribution of nearest - neighbor level spacing is characterized by the poisson ( exponential ) distribution@xcite , while for quantum systems whose classical counterparts are strongly chaotic , the quantal level statistics are well characterized by the random matrix theory which gives level - spacing distribution obeying the wigner distribution@xcite ..
Please generate the next two sentences of the article | level statistics for the integrable quantum systems has been theoretically studied by berry - tabor@xcite , sinai@xcite , molchanov@xcite , minami@xcite , bleher@xcite , connors and keating@xcite , and marklof@xcite , and have been the subject of many numerical investigations .
still its mechanism is not well understood , the appearance of the poisson distributions is now widely admitted as a universal phenomenon in generic integrable quantum systems . |
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