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12,700 |
Suppose that you have an abstract for a scientific paper: we consider a modification of the berry conjecture for eigenmode statistics in wave - bearing systems .
the eigenmode correlator is conjectured to be proportional to the imaginary part of the green s function .
the generalization is applicable not only to scalar waves in the interior of homogeneous isotropic systems where the correlator is a bessel function , but to arbitrary points of heterogeneous systems as well . in view of recent experimental measurements , expressions for the intensity correlator in chaotic plates
are derived . in 1977 berry
conjectured that the higher eigenmodes of a ray - chaotic hamiltonian , in particular , a billiard , should be statistically indistinguishable from a superposition of plane standing waves of all directions , with uncorrelated amplitudes and phases @xcite ; the idea is also found in @xcite .
one immediate consequence is that the modes are gaussian random functions , with correlations given by @xmath0 where brackets @xmath1 represent spatial average over position @xmath2 , * * * * @xmath3 * * * * is an unimportant normalization factor , @xmath4 is a separation distance , and * @xmath5 * is the wavenumber that appears in the governing helmholtz equation , @xmath6 .
another immediate consequence is that the intensity correlator is@xmath7.\label{eq : scalarintensitycorrelator}\ ] ] berry established the conjecture for an asymptotic regime in which wavelengths are much less than system size .
it is only approximate at finite wavelength , i.e , in practice .
the conjecture has been shown to be incorrect at finite wavelength , inasmuch as many modes show evidence of scarring @xcite , existence of which may be understood in the light of the `` quantum equidistribution theorem '' put forth by shnirelman @xcite .
the conjecture is manifestly incorrect if attention is restricted to points near a boundary where , locally , plane waves are correlated with their reflections .
nevertheless , numerical and experimental evidence shows that it is widely....
And you have already written the first three sentences of the full article: we start calculation of the full intensity correlator by first considering the normal modes of the rayleigh - lamb spectrum @xcite . the displacement vector of these modes is given by@xmath64f\left(x_{1},x_{2}\right),\ ] ] with @xmath65 satisfying a scalar 2d helmholtz equation : @xmath66f\left(x_{1},x_{2}\right)=0 $ ] .
the displacement components @xmath67 and @xmath68 are the solutions of a boundary - value ode in @xmath69 . with the vertical wavenumbers of longitudinal and shear waves defined as @xmath70 , and @xmath71 ,
one deduces the dispersion relation for the odd and even up / down parity modes@xmath72^{\pm1},\ ] ] where @xmath73 in the exponent corresponds to the odd parity modes , and @xmath74 to the even modes ..
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the dispersion relation gives the wavenumbers of the odd ( @xmath29 ) and even modes ( @xmath60 ) as multi - branched implicit functions of the frequency : @xmath75 .
expressions for @xmath67 and @xmath68 of the odd and even modes respectively are by specifying a complete set of solutions @xmath65 in the plane ( for example , standing plane waves or standing cylindrical waves ) , we construct the modes of an infinite plate .
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12,701 |
Suppose that you have an abstract for a scientific paper: at the tev scale , heavy quarks , for example the 4th generation quarks of the standard model with four generations , can form condensates which dynamically break the electroweak symmetry .
a dense quark system may form other types of condensates which dynamically break the lorentz symmetry .
these condensates are described by a nambu - jona - lasinio type effective action , similar to the quark condensation models in hadronic matter with finite density .
the vacua corresponding to these two types of condensates compete for the global minimum of the effective potential , depending on the energy scale and the related strong dynamics .
the resultant goldstone gauge boson may produce observable effects in relativistic heavy - ion colliders . .
And you have already written the first three sentences of the full article: the higgs sector of the standard model might have a landau - ginzburg effective description , in which the higgs doublet is a condensate of fermion and antifermion .
the constituent fermions could be the top quark in the top - quark condensation models , or technifermions in the technicolor models ( see refs . for reviews ) .
a new interaction , e.g. , a four - fermion interaction or technicolor , is introduced at the composite scale ..
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recently it has been shown@xcite that in the standard model with four generations ( sm4 ) , the renormalization group evolutions of the yukawa and quartic couplings can reach a quasi - fixed point at the tev scale ( @xmath0 ) , where the yukawa couplings become strong enough for the 4th generation to form condensates .
this can be seen by considering a nonrelativistic higgs - exchange potential between a fermion and an antifermion @xmath1 by numerical analysis , the bound state condition is found to be @xmath2 , where @xmath3 is expressed in terms of the yukawa couplings and the quartic couplings as @xmath4 .
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12,702 |
Suppose that you have an abstract for a scientific paper: possible crystalline modifications of chemical compounds at low temperatures correspond to local minima of the energy landscape . determining these minima via simulated annealing
is one method for the prediction of crystal structures , where the number of atoms per unit cell is the only information used .
it is demonstrated that this method can be applied to covalent systems , at the example of boron nitride , using _ ab initio _ energies in all stages of the optimization , i.e. both during the global search and the subsequent local optimization .
ten low lying structure candidates are presented , including both layered structures and 3d - network structures such as the wurtzite and zincblende types , as well as a structure corresponding to the @xmath0-beo type . .
And you have already written the first three sentences of the full article: the knowledge of the crystal structure of a solid compound is one of the basic questions in solid state theory@xcite . since the early 1990 s
, an effort has been made to develop methods to predict structures of solids without any experimental information about the structure .
the starting point is the realization that any ( meta)stable modification of a ( solid ) compound corresponds to a locally ergodic region on the energy landscape of the chemical system . for low temperatures ,.
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such regions are centered on local minima of the energy that are surrounded by sufficiently high energy barriers . since both the thermodynamically stable and the multitude of kinetically stable modifications are of interest , the global search
is not restricted to the determination of the global minimum , but also includes local minima @xcite .
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12,703 |
Suppose that you have an abstract for a scientific paper: we study how the spectral properties of resonance fluorescence propagate through a two atom system . within the weak driving field approximation we find that , as we go from one atom to the next , the power spectrum exhibits both sub natural linewidth narrowing and large asymmetries while the noise spectrum of the squeezed quadrature narrows but remains otherwise unchanged .
analytical results for the observed spectral features of the fluorescence are provided and their origin is thoroughly discussed . .
And you have already written the first three sentences of the full article: since the prediction @xcite and observation @xcite of the three peaked fluorescence spectrum of a strongly driven two level atom , the spectral features of atomic fluorescence
have both provided fundamental insight into the photon atom interaction and revealed a variety of interesting quantum features .
photon anti bunching together with sub .
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poissonian counting statistics have long been predicted @xcite and experimentally observed @xcite .
the phenomenon of squeezing in resonance fluorescence has also been the object of a rather intense research activity @xcite .
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12,704 |
Suppose that you have an abstract for a scientific paper: high multiplicity events in proton - proton collisions at the large hadron collider exhibit features resembling those found in relativistic nuclear collisions , indicating possibility of formation of similar partonic medium .
formation of partonic medium in hadronic collision means happening of change in phase of matter , as is predicted by quantum chromodynamics . analyzing the identified particle spectra data from @xmath0 collision
, we observe a signal of plausible change of phase between thermalized partonic matter and hadronic one , in terms of change in effective number of degrees of freedom , as has been revealed by the latest calculation in the framework of the lattice quantum chromodynamics .
the result is compared with similar analysis of @xmath1 data and simulated events of @xmath0 collisions . .
And you have already written the first three sentences of the full article: the minuscular universe of high energy - density and temperature , immediately after the big bang , evolved through a state of an exotic phase of matter , the quark - gluon plasma ( qgp ) @xcite , that survived for some microseconds only .
the qgp - the plasma state in quantum chromodynamics ( qcd)@xcite , the theory of strong interaction - can be created also in the laboratory @xcite , in relativistic heavy - ion collisions . the formation of the qcd plasma necessitates accomplishment of thermodynamic equilibrium . in heavy - ion collisions , the local thermodynamic equilibrium is assumed to obtain the equation of state for the space - time evolution of the system in the framework of the relativistic hydrodynamics @xcite .
eventually , the formation of qgp in heavy - ion collisions is established mainly by characterizing the system in the hydrodynamic model , implying occurrence of the qcd phase - change ..
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the proton - proton ( @xmath2 ) collision , on the other hand , is considered as the elementary interaction by most of the topical models which do not endorse formation of any medium , whatsoever .
one may also question if the mean free path of the constituent particles , the size and the lifetime of the produced medium , if any , in @xmath2 collisions are conducive to the formation of qgp or not .
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12,705 |
Suppose that you have an abstract for a scientific paper: the outstanding problem of controlling complex networks is relevant to many areas of science and engineering , and has the potential to generate technological breakthroughs as well .
we address the physically important issue of the energy required for achieving control by deriving and validating scaling laws for the lower and upper energy bounds .
these bounds represent a reasonable estimate of the energy cost associated with control , and provide a step forward from the current research on controllability toward ultimate control of complex networked dynamical systems .
complex networks are ubiquitous in natural , social , and man - made systems , such as gene regulatory networks , social networks , mobile sensor networks and so on @xcite .
a network is composed of nodes and edges .
the nodes represent individual units ( e.g. , genes , persons , sensors ) and the edges represent connections or interactions between the nodes .
the state of a node ( e.g. , protein being expressed , opinion of a person , position of a sensor ) normally evolves over time . and
the evolution depends not only on the node s intrinsic dynamics but also on the couplings with its nearest neighbors @xcite . on one hand ,
the couplings between nodes increase the complexity of collective behaviors , which stimulates much interest of modeling , analyzing , and predicting dynamical processes on complex networks @xcite . on the other hand
, one may utilize the couplings to control a whole network , i.e. , steering a network from any initial state ( vector ) to a desired final state , by driving only a few suitable nodes with external signals . in this direction
there are good attempts recently from physics @xcite , biology @xcite and engineering @xcite research communities . among others ,
liu _
et al .
_ studied the controllability of various real - world networks , i.e. , the ability to steer a complex network as measured by the minimum number of driver nodes .
a main result was that the number of driver....
And you have already written the first three sentences of the full article: in the main text we argue that , for large control time @xmath0 , if @xmath34 is semi positive definite ( pd ) , the lower bound of the energy cost @xmath70 will decay as @xmath77 and , if @xmath34 is semi negative definite ( nd ) the upper bound of the energy cost @xmath92 will also decay as @xmath77 . to provide numerical confirmation for these theoretical results
, we consider the situation of controlling an undirected network of 20 nodes which can be controllable by one single driver node . just as in the main text ,
let nodal dynamics be @xmath128 where @xmath129 is the strength of node @xmath10 ..
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setting @xmath130 so that @xmath34 is semi nd , we obtain the decay behavior of @xmath70 , as depicted in fig .
[ semi](a ) . however , if @xmath131 , @xmath34 becomes semi pd . in this case
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12,706 |
Suppose that you have an abstract for a scientific paper: how a galaxy regulates its sne energy into different interstellar / circumgalactic medium components strongly affects galaxy evolution . based on the _ jvla _ d - configuration c- ( 6 ghz ) and l - band ( 1.6 ghz ) continuum observations , we perform statistical analysis comparing multi - wavelength properties of the chang - es galaxies .
the high - quality _ jvla _ data and edge - on orientation enable us for the first time to include the halo into the energy budget for a complete radio - flux - limited sample .
we find tight correlations of @xmath0 with the mid - ir - based sfr .
the normalization of our @xmath1 relation is @xmath22 - 3 times of those obtained for face - on galaxies , probably a result of enhanced ir extinction at high inclination .
we also find tight correlations between @xmath0 and the sne energy injection rate @xmath3 , indicating the energy loss via synchrotron radio continuum accounts for @xmath4 of @xmath5 , comparable to the energy contained in cr electrons .
the integrated c - to - l - band spectral index is @xmath6 for non - agn galaxies , indicating a dominance by the diffuse synchrotron component .
the low - scatter @xmath7/@xmath8 relationships have super - linear logarithmic slopes at @xmath9 in l - band ( @xmath10/@xmath11 ) while consistent with linear in c - band ( @xmath12/@xmath13 ) .
the super - linearity could be naturally reproduced with non - calorimeter models for galaxy disks . using _
chandra _ halo x - ray measurements , we find sub - linear @xmath14 relations .
these results indicate that the observed radio halo of a starburst galaxy is close to electron calorimeter , and a galaxy with higher sfr tends to distribute an increased fraction of sne energy into radio emission ( than x - ray ) . .
And you have already written the first three sentences of the full article: the energetic feedback from supernovae ( sne ) and massive stellar winds are crucial in setting the basic properties of galaxies , including masses , sizes , and star formation histories , as studied in numerical and semi - analytical models ( e.g. , @xcite and references therein ) .
in particular , this stellar feedback is thought to be the most important energy source for the multi - phase circumgalactic medium ( cgm ) around galaxies without an active galactic nucleus ( agn ) .
the cgm is comprised of multi - phase gas ( hot gas @xmath15 , e.g. , @xcite ; warm - hot intergalactic medium @xmath16 , e.g.,@xcite ; cool gas @xmath17 , e.g. , @xcite ; and cold gas @xmath18 , e.g. , @xcite ) as well as relativistic particles ( cosmic rays ; crs ) and magnetic fields ( e.g. , @xcite ) , which produce broad - band emission via various emitting mechanisms . until now , how the galaxies distribute their feedback energy into different interstellar medium ( ism ) or cgm phases is still poorly understood ( e.g. , see @xcite and references therein ) ..
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both the diffuse radio and x - ray emission in and around galaxies are thought to be closely related to sne feedback .
the radio continuum emission at ghz frequencies is mainly produced by the synchrotron energy loss of relativistic electrons at @xmath19 energy .
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12,707 |
Suppose that you have an abstract for a scientific paper: the multiphoton ionization and photoelectron spectra of magnesium were studied at laser intensities of up to @xmath0 using 150 fs laser pulses of a wavelength of 400 nm .
the results indicated that a variety of different ionization mechanisms played a role in both types of spectra .
a theoretical model describing the processes is presented and the routes to ionization are identified .
the work demonstrates the significance of the two electron nature of the atom in interpreting the experimental results . .
And you have already written the first three sentences of the full article: the behavior of atoms in intense electro - magnetic fields has been under investigation since the advent of the laser . especially since the development of short pulse , high intensity systems
, experiments have revealed a multitude of novel effects such as multiphoton ionization ( mpi)@xcite , above threshold ionization ( ati)@xcite , harmonic generation@xcite etc .
most of the theoretical models originally proposed to describe the observations involved essentially a single electron interacting with the electromagnetic field ..
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this approximation has led to significant understanding of the atomic behavior in the field . however
, the multi - electron nature of most atoms can play a significant role under certain circumstances .
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12,708 |
Suppose that you have an abstract for a scientific paper: we use the measured x - ray luminosity function ( xlf ) of high - mass x - ray binaries ( hmxbs ) in nearby star - forming galaxies to constrain the common envelope ( ce ) mechanisms , which play a key role in governing the binary evolution .
we find that the xlf can be reproduced quite closely under both ce mechanisms usually adopted , i.e. , the @xmath0 formalism and the @xmath1 algorithm , with a reasonable range of parameters considered .
provided that the parameter combination is the same , the @xmath1 algorithm is likely to produce more hmxbs than the @xmath0 formalism , by a factor of up to @xmath2 10 . in the framework of the @xmath0 formalism
, a high value of @xmath0 is required to fit the observed xlf , though it does not significantly affect the global number of the hmxb populations .
we present the detailed components of the hmxb populations under the @xmath1 algorithm and compare them with those in zuo et al . and observations .
we suggest the distinct observational properties , as well as period distributions of hmxbs , may provide further clues to discriminate between these two types of ce mechanisms . .
And you have already written the first three sentences of the full article: the common envelope ( ce ) evolution is among the most important and least well - constrained processes in binary evolution .
it is commonly thought to occur if the mass transfer is dynamically unstable .
the result is that the accreting star spirals into the envelope of the donor star ( see * ? ? ?.
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* ; * ? ? ?
* ; * ? ? ?
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12,709 |
Suppose that you have an abstract for a scientific paper: gaussianizing transformations are used statistically in many non - cosmological fields , but in cosmology , we are only starting to apply them . here
i explain a strategy of analyzing the 1-point function ( pdf ) of a spatial field , together with the ` essential ' clustering statistics of the gaussianized field , which are invariant to a local transformation . in cosmology , if the tracer sampling is sufficient , this achieves two important goals .
first , it can greatly multiply the fisher information , which is negligible on nonlinear scales in the usual @xmath0 statistics .
second , it decouples clustering statistics from a local bias description for tracers such as galaxies . .
And you have already written the first three sentences of the full article: cosmologists have been trained to look at the world through linear two - point statistics : the power spectrum and correlation function of the overdensity field , @xmath1 .
this is for good reason : linear perturbation theory is naturally expressed in terms of the power spectrum of @xmath0 , which sources gravity .
the raw power spectrum works well for the nearly gaussian cosmic microwave background ( cmb ) as well , and the galaxy and matter density fields on large scales . also , @xmath0 has the benefit that the power at a given scale is largely invariant if the resolution is increased ..
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but the usual correlation function and power spectrum dramatically lose constraining power in a non - gaussian field such as the matter or galaxy density field on small scales , so to reach the highest - possible precision in cosmology , other approaches are necessary . in a 2@xmath2mpc - thick slice of the 500@xmath2mpc millennium simulation @xcite , viewed with an unfortunate linear color scale . _
* upper middle * _ : the same slice , rank - order - gaussianized , i.e. , applying a function on each pixel to give a gaussian pdf . _ * upper right * _ : the @xmath0 field with its fourier phases randomized . _ * lower left : * _ pdfs of the upper - left and upper - right 3d fields . _ * lower right : * _ @xmath3 and @xmath4 of @xmath0 ( red ) and @xmath5 ( blue ) , measured from each of several 2d slices such as those shown in the upper - left and middle panels .
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12,710 |
Suppose that you have an abstract for a scientific paper: the face lattice of the _ permutohedron _ realizes the combinatorics of linearly ordered partitions of the set @xmath0=\{1, ... ,n\}$ ] .
similarly , the _ cyclopermutohedron _ is a virtual polytope that realizes the combinatorics of cyclically ordered partitions of @xmath0 $ ] .
it is known that the volume of the standard permutohedron equals the number of trees with @xmath1 labeled vertices multiplied by @xmath2 . the number of integer points of the standard permutohedron equals the number of forests on @xmath1 labeled vertices . in the paper
we prove that the volume of the cyclopermutohedron also equals some weighted number of forests , which eventually reduces to zero .
we also derive a combinatorial formula for the number of integer points in the cyclopermutohedron .
another object of the paper is the _ configuration space of a polygonal linkage @xmath3_. it has a cell decomposition @xmath4 related to the face lattice of cyclopermutohedron . using this relationship
, we introduce and compute the volume @xmath5 . .
And you have already written the first three sentences of the full article: the _ standard permutohedron _ @xmath6 is defined ( see @xcite ) as the convex hull of all points in @xmath7 that are obtained by permuting the coordinates of the point @xmath8 .
it has the following properties : 1 .
@xmath6 is an @xmath9-dimensional polytope ..
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the @xmath10-faces of @xmath6 are labeled by ordered partitions of the set @xmath0=\{1,2, ... ,n\}$ ] into @xmath11 non - empty parts .
a face @xmath12 of @xmath6 is contained in a face @xmath13 iff the label of @xmath12 refines the label of @xmath13 . + here and in the sequel , we mean the order - preserving refinement .
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12,711 |
Suppose that you have an abstract for a scientific paper: we consider corrections to the underlying cosmology due to secondary contributions from weak gravitational lensing , the integrated sachs - wolfe effect , and the sunyaev - zeldovich effect contained in the trispectrum .
we incorporate these additional contributions to the covariance of a binned angular power spectrum of temperature anisotropies in the analysis of current and prospective data sets .
although recent experiments such as acbar and cbi are not particularly sensitive to these additional non - gaussian effects , the interpretation of planck and cmbpol anisotropy spectra will require an accounting of non - gaussian covariance leading to a degradation in cosmological parameter estimates by up to @xmath0 and @xmath1 , respectively . .
And you have already written the first three sentences of the full article: the cosmic microwave background s ( cmb ) ability to constrain the cosmological parameters has driven a large variety of cmb experiments .
the high quality measurements of the temperature and polarization of the cmb are compatible with a flat universe with nearly scale invariant fluctuations .
the sensitivity to small angular scales of recent experiments such as wmap5 @xcite , acbar @xcite and cbi @xcite give us a better understanding of anisotropies from local large scale structure ( lss ) and from non - linear effects such as weak gravitational lensing ..
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the non - gaussianity of these fluctuations can have an effect in the estimation of the cosmological parameters , especially for future experiments .
however , possible non - gaussian effects have not been considered in previous analyses , under the assumption that they are negligible .
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12,712 |
Suppose that you have an abstract for a scientific paper: the oscillation frequency of @xmath0-@xmath1 mixing ( @xmath2 ) has been measured using 29.1 @xmath3 of data collected with the belle detector at kekb .
this measurement is made through the distributions of the proper decay time difference of @xmath4 pairs in events tagged as same- and opposite - flavor decays . in each event , one @xmath4 is fully reconstructed in a flavor - specific hadronic decay mode , while the flavor of the other is extracted through a likelihood calculated from the @xmath5-flavor information carried in its final decay products .
we obtain @xmath6 , where the first error is statistical and the second error is systematic . _
pacs : _
12.15.hh , 11.30.er , 13.25.hw to , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , and .
And you have already written the first three sentences of the full article: in the standard model , @xmath0-@xmath1 oscillation occurs through second order weak interactions where the dominant contribution has an internal loop that contains virtual @xmath7-quarks . as a result , the oscillation frequency @xmath8 is related to the cabibbo - kobayashi - maskawa ( ckm ) matrix elements @xmath9 and @xmath10 @xcite . since @xmath11 is expected to be very close to 1 , a precise measurement of @xmath8 , in principle , provides a method to determine @xmath12 .
although the extraction of @xmath12 from @xmath8 is currently hampered by theoretical uncertainties on hadronic matrix elements , precision measurements of @xmath8 could be important for future determinations of @xmath12 .
in addition , @xmath0-@xmath1 mixing is one of the sources of @xmath13 violation in @xmath0 decays and a good knowledge of @xmath8 is important for precise measurements of these @xmath13 asymmetries . since the first observation of @xmath0-@xmath1 mixing @xcite , a number of measurements of @xmath8.
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have been reported @xcite .
recently , asymmetric @xmath4-factory experiments operated at the @xmath14 resonance have significantly improved the precision of @xmath8 @xcite . in this letter
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12,713 |
Suppose that you have an abstract for a scientific paper: a measured solenoid is a laminated space endowed with a tranversal measure invariant by holonomy .
a measured solenoid immersed in a smooth manifold produces a closed current ( known as generalized ruelle - sullivan current ) .
uniquely ergodic solenoids are those for which there is a unique ( up to scalars ) transversal measure .
it is known that for any smooth manifold , any real homology class is represented by a uniquely ergodic solenoid . in this paper , we prove that the currents associated to uniquely ergodic solenoids are dense in the space of closed currents , therefore proving the abundance of such objects . .
And you have already written the first three sentences of the full article: in @xcite , the authors introduced the concept of measured solenoid as a laminated space @xmath0 endowed with a transversal measure @xmath1 .
given a measured oriented solenoid @xmath2 , any smooth map @xmath3 into a differentiable manifold @xmath4 gives rise , by integration of forms , to a closed current @xmath5 whose associated homology class @xmath6\in h_k(m,{{\mathbb r}})\,\ ] ] is called the generalized ruelle - sullivan class . a special role in the theory is played by the solenoids which have an ergodicity property .
a uniquely ergodic solenoid is a solenoid @xmath0 for which there is a unique ( up to multiples ) transversal measure , and this measure has support the whole of the solenoid ..
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in this situation , the `` geometry '' ( that is , the solenoid itself ) determines the `` measure '' .
this has a more precise significance if we note the following : for a uniquely ergodic immersed solenoid @xmath3 , take one leaf @xmath7 , and an exhaustion @xmath8 by compact sets such that @xmath9 can be capped off by a `` small '' cap , thus defining a homology class @xmath10\in h_k(m,{{\mathbb z}})$ ] .
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12,714 |
Suppose that you have an abstract for a scientific paper: the interest on the solar diameter variations has been primary since the scientific revolution for different reasons : first the elliptical orbits found by kepler in 1609 was confirmed in the case of the earth , and after the intrinsic solar variability was inspected to explain the climate changes .
the ccd solar astrolabe of the observatrio nacional in rio de janeiro made daily measurements of the solar semi - diameter from 1998 to 2009 , covering most of the cycle 23 , and they are here presented with the aim to evidence the observed variations .
some instrumental effects parametrizations have been used to eliminate the biases appeared in morning / afternoon data reduction .
the coherence of the measurements and the influence of atmospheric effects are presented , to discuss the reliability of the observed variations of the solar diameter .
their amplitude is compatible with other ground - based and satellite data recently published . .
And you have already written the first three sentences of the full article: the interest on the solar diameter variations has been prioritary during the last four centuries of astronomy with and without the telescope . during 1600 the verification of
the keplerian hypothesis of elliptical earth s orbit was possible thanks to measurements of the seasonal variations of the angular diameter of the sun made by g. d. cassini and g. b. riccioli from 1655 to 1666 at the _ heliometer _ of s. petronio in bologna .
this was a pinhole solar telescope of the basilica of st ..
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petronius in bologna @xcite . later in 1700 the interest of the astronomers was more focused on the earth s axis orientation , with the variation of the obliquity @xmath0 . to measure this parameter it was necessary to know better the position of the solar center , than the diameter .
the giant pinhole telescopes @xcite could operate on a complete yearly range of zenithal distances of @xmath1 without optical distortions , excepted the atmospheric refraction , and for this reason these instruments continued successfully their operations until the end of the century even if their imaging capability was comparatively lower than usual telescopes .
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12,715 |
Suppose that you have an abstract for a scientific paper: the dynamical signatures of the interaction between galaxies in clusters and the intracluster medium ( icm ) can potentially yield significant information about the structure and dynamical history of clusters . to develop our understanding of this phenomenon we present results from numerical modelling of the galaxy / icm interaction , as the galaxy moves through the cluster .
the simulations have been performed for a broad range , of icm temperatures ( @xmath0 , 4 and @xmath1 ) , representative of poor clusters or groups through to rich clusters .
there are several dynamical features that can be identified in these simulations ; for supersonic galaxy motion , a leading bow - shock is present , and also a weak gravitationally focussed wake or tail behind the galaxy ( analogous to bondi - hoyle accretion ) . for galaxies with higher mass - replenishment rates and a denser interstellar medium ( ism ) , the dominant feature is a dense ram - pressure stripped tail . in line with other simulations , we find that the icm / galaxy ism interaction can result in complex time - dependent dynamics , with ram - pressure stripping occurring in an episodic manner . in order to facilitate this comparison between the observational consequences of dynamical studies and x - ray observations we have calculated synthetic x - ray flux and hardness maps from these simulations .
these calculations predict that the ram - pressure stripped tail will usually be the most visible feature , though in nearby galaxies the bow - shock preceeding the galaxy should also be apparent in deeper x - ray observations .
we briefly discuss these results and compare with x - ray observations of galaxies where there is evidence of such interactions .
galaxies : clusters : kinematics and dynamics - galaxies : interactions - intergalactic medium - x - rays : galaxies - galaxies : clusters : virgo .
And you have already written the first three sentences of the full article: most galaxies are not isolated ( tully 1987 ) but are members of groups or clusters which are gravitationally bound , though not necessarily virialised . galaxies in such systems
may experience a number of types of interaction with their environment : galaxy - galaxy encounters , which may trigger starbursts and can culminate in galaxy merging ( schweizer 1982 ) , interaction with the potential of the system as a whole , which may for example , result in tidal stripping of loosely bound material from galaxy outskirts ( mamon 1987 ) , and finally hydrodynamical interaction between the interstellar medium ( ism ) in a galaxy , and any intergalactic gas trapped in the potential well of the galaxy system .
it is the last of these processes which is the subject of the present study ..
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interaction with the surrounding intracluster medium ( icm ) may have a significant impact on the gas within a galaxy whenever it sweeps through a substantial mass of hot gas in its motion within a group or cluster . in practice
, the hot icm dominates the baryon content of galaxy clusters ( white & fabian 1995 ) and is also a major baryonic component within many galaxy groups ( mulchaey _ et al . _
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Suppose that you have an abstract for a scientific paper: the present paper investigates the properties of the dust mass loss in stars populating the giant branch of the globular cluster 47 tuc , by combining isocam and denis data .
raster maps of 5 fields covering areas ranging from @xmath0 to @xmath1arcmin@xmath2 at different distances from the center of the cluster have been obtained with isocam at 11.5@xmath3 m ( lw10 filter ) .
the covered fields include most of the red variables known in this cluster . a detection threshold of about 0.2 mjy is achieved , allowing to detect giant stars at 11.5@xmath3 m all the way down to the horizontal branch .
no dust - enshrouded asymptotic giant branch stars have been found in the observed fields , contrary to the situation encountered in lmc / smc globular clusters with larger turnoff masses .
+ the color index @xmath4-[2]$ ] ( based on the iso 11.5 @xmath3 m flux and on the denis @xmath5 magnitude ) is used as a diagnostic of dust emission ( and hence dust mass loss ) . its evolution with luminosity along the giant branch
reveals that dust mass loss is only present in v3 ( the only cluster mira variable observed in the present study ) and in v18 , a star presenting intermittent variability .
this conclusion confirms the importance of stellar pulsations in the dust formation and ensuing mass loss . .
And you have already written the first three sentences of the full article: stellar mass loss is an essential ingredient in the modelling of several important astrophysical processes .
it plays a key role in the chemical evolution of the galaxy , by returning to the interstellar medium the ashes of the nuclear - burning processes that took place during the star s lifetime . in asymptotic giant branch ( agb )
stars , the mass loss rate is so large that the evolutionary timescale is controlled by mass loss rather than by nuclear burning ..
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the general principles governing mass loss on the agb are understood .
shock waves associated with the stellar pulsation push the gas far enough above the photosphere for dust to start condensing .
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Suppose that you have an abstract for a scientific paper: clustering coefficient is an important topological feature of complex networks .
it is , however , an open question to give out its analytic expression on weighted networks yet .
here we applied an extended mean - field approach to investigate clustering coefficients in the typical weighted networks proposed by barrat , barthlemy and vespignani ( bbv networks ) .
we provide analytical solutions of this model and find that the local clustering in bbv networks depends on the node degree and strength .
our analysis is well in agreement with results of numerical simulations . .
And you have already written the first three sentences of the full article: the concept of weight plays an important role in characterizing the features of complex systems in nature , since many different correlations in the real world can be represented by weighted links . in the past decade , as an emerging network dynamics , weight dynamics has attracted a large number of scientific communities @xcite .
it has been shown that many biological , technological , and social systems are best described by weighted networks , as the nodes interact with each other with varying strength . to describe the variety ,
a link between two nodes is associated with a weight in the weighted network ..
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the weight of a link can represent different properties for different networks .
for a social network , link weight can indicates the intimacy between two individuals @xcite ; for the internet , link weight can represent the bandwidth of an optical cable between two routers @xcite ; for the world - wide aviation network , link weights can reflect the annual volume of passengers traveling between two airports @xcite ; and for the _ e. coli _ metabolic network , link weight can encode the optimal metabolic fluxes between two metabolites @xcite .
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Suppose that you have an abstract for a scientific paper: we discuss the creation of non - classical light from collective atomic states that are prepared in a ring - shaped lattice .
these states are realized by exploiting the strong interaction between atoms in high lying energy levels - so - called rydberg states - and yield a resource for creating excitations of the electromagnetic field that carry few photons .
we characterize the properties of these photonic states showing that they are determined by the interplay between the ring geometry , the structure of the atomic resource states and the collectivity in the photon emission which is controlled by the lattice spacing .
the system permits the creation of single photons with well - defined orbital angular momentum and two - photon states that are entangled in orbital angular momentum . .
And you have already written the first three sentences of the full article: the coupling of atoms to light has been exploited since the early days of atomic physics to gain an insight into the structure of atoms and molecules .
recently , there has been a great deal of interest in the quantum interface between light and an atomic ensemble @xcite and in using the coherent coupling between these two systems for quantum information processing , quantum information storage or the creation of deterministic photon sources @xcite .
such photon sources rely on the ability to create certain entangled quantum states in atomic ensembles which are then subsequently converted into excitations of the electromagnetic field @xcite ..
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ultra cold atoms provide a toolbox for the creation of such atomic states .
the reason is rooted in the versatility of these systems , such as the tunability of their interactions and the advanced techniques that have been developed for their trapping and manipulation @xcite . in particular , the exaggerated properties of highly excited ( rydberg ) atoms @xcite can be exploited in order to create entangled many - particle states . in a recent work @xcite this was shown for a system in which the atoms are confined to a deep ring lattice . here
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Suppose that you have an abstract for a scientific paper: we study interacting scalar field theory non - minimally coupled to gravity in the frw background .
we show that for a specific choice of interaction terms , the energy - momentum tensor of the scalar field @xmath0 vanishes , and as a result the scalar field does not gravitate .
the naive space dependent solution to equations of motion gives rise to singular field profile .
we carefully analyze the energy - momentum tensor for such a solution and show that the singularity of the solution gives a subtle contribution to the energy - momentum tensor .
the space dependent solution therefore is not non - gravitating .
our conclusion is applicable to other space - time dependent non - gravitating solutions as well .
we study hybrid inflation scenario in this model when purely time dependent non - gravitating field is coupled to another scalar field @xmath1 . .
And you have already written the first three sentences of the full article: non - minimal coupling of the dilaton and the metric is a generic feature of any string theory(see e.g. , @xcite ) .
while usual compactifications do not generate any potential , in the low energy limit , for the dilaton or other massless scalars coming from the string theory , it is generally believed that a potential is generated for them when one considers flux compactifications@xcite .
generation of potential for scalar fields in the flux compactification , makes them an arena for study of physics of the early universe ..
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however , if one looks at models of inflation in these compactifications , a generic problem crops up in the slow roll inflation .
one of the slow roll parameters , @xmath2 , turns out to be sensitive to the size of compactified space and one finds that the slow roll condition , i.e. , @xmath3 is harder to achieve@xcite .
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Suppose that you have an abstract for a scientific paper: we present commissioning data from the osiris integral field spectrograph ( ifs ) on the keck ii 10 m telescope that demonstrate the utility of adaptive optics ifs spectroscopy in studying faint close - in sub - stellar companions in the haloes of bright stars .
our @xmath0@xmath12000 @xmath2- and @xmath3-band spectra of the sub - stellar companion to the 110 myr - old gq lup complement existing @xmath4-band spectra and photometry , and improve on the original estimate of its spectral type .
we find that gq lup b is somewhat hotter ( m6l0 ) than reported in the discovery paper by neuh " auser and collaborators ( m9l4 ) , mainly due to the surface - gravity sensitivity of the @xmath4-band spectral classification indices used by the discoverers .
spectroscopic features characteristic of low surface gravity objects , such as lack of alkali absorption and a triangular @xmath3-band continuum , are indeed prominent in our spectrum of gq lup b. the peculiar shape of the @xmath3-band continuum and the difference between the two spectral type estimates is well explained in the context of the diminishing strength of h@xmath5 collision induced absorption with decreasing surface gravity , as recently proposed for young ultra - cool dwarfs by kirkpatrick and collaborators . using our updated spectroscopic classification of gq lup b and a re - evaluation of the age and heliocentric distance of the primary , we perform a comparative analysis of the available sub - stellar evolutionary models to estimate the mass of the companion .
we find that the mass of gq lup b is 0.0100.040 .
hence , it is unlikely to be a wide - orbit counterpart to the known radial - velocity extrasolar planets , whose masses are @xmath60.015 .
instead , gq lup a / b is probably a member of a growing family of very low mass ratio widely separated binaries discovered through high - contrast imaging . .
And you have already written the first three sentences of the full article: after more than a decade of precision radial velocity surveys , we know that extrasolar giant planets exist around at least 515% of sun - like stars @xcite .
unfortunately , these planets lie at small angular separations ( @xmath7@xmath8 ) with high contrast ( @xmath9@xmath10 ) from their host stars , and therefore , every known radial - velocity extrasolar planet is beyond the current technical limitations for direct imaging . as a result ,
the physical properties of these radial velocity planets ( except for several transiting planets ) remain largely unknown . however ,.
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recent efforts in high - contrast imaging with adaptive optics ( ao ) have lead to the discovery of two distinct sub - stellar companions , 2massw j1207334393254 b @xcite and gq lup b @xcite , at wider ( @xmath9@xmath11 ) angular separations from their primary stars and with estimated masses comparable to those of known radial velocity planets ( @xmath615 jupiter masses [ ] ) . unlike the close - in ( @xmath66 au ) radial velocity planets , whose ( minimum ) masses are inferred directly from the orbital periodicity of the doppler signal , the masses of these two wider ( @xmath940 au ) companions have not been established dynamically due to their much longer orbital periods . instead , the estimated masses are based entirely on theoretical models of sub - stellar evolution @xcite .
presently , such models have very few empirical constraints , and at the young ( @xmath610 myr ) ages of the two directly - imaged planetary - mass companions , their predictions are very sensitive to the initial conditions .
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Suppose that you have an abstract for a scientific paper: we compare the performance of different clustering algorithms applied to the task of unsupervised text categorization .
we consider agglomerative clustering algorithms , principal direction divisive partitioning and ( for the first time ) superparamagnetic clustering with several distance measures .
the algorithms have been applied to test databases extracted from the reuters-21578 text categorization test database .
we find that simple application of the different clustering algorithms yields clustering solutions of comparable quality . in order to achieve considerable improvements of the clustering results it
is crucial to reduce the dictionary of words considered in the representation of the documents .
significant improvements of the quality of the clustering can be obtained by identifying discriminative words and filtering out indiscriminative words from the dictionary .
we present two methods , each based on a resampling scheme , for selecting discriminative words in an unsupervised way .
keywords : clustering , text categorization , document classification , feature selection , random subsampling 2 .
And you have already written the first three sentences of the full article: automatic text categorization has many interesting applications in science and business . for instance formatting the results of a web - search query , sorting news messages according to topics or sorting incoming email with different concerns .
irrespective of the application two principal cases are distinguished . in the first case
the categories are known and the algorithm should assign any document to one of the known categories . then it is useful to teach the algorithm the considered categories and their word fields by using a training set of labeled documents before it will be applied to unknown documents ..
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the algorithmic solutions to this problem fall into the category of _ supervised _ learning . in the other case
the categorization of documents has to be done without knowing the categories nor their number .
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Suppose that you have an abstract for a scientific paper: yes , there is . a new kind of gauge theory is introduced , where the minimal coupling and corresponding covariant derivatives are defined in the space of functions pertaining to the functional schrdinger picture of a given field theory . while , for simplicity , we study the example of a @xmath0 symmetry , this kind of gauge theory can accommodate other symmetries as well . we consider the resulting relativistic nonlinear extension of quantum mechanics and show that it incorporates gravity in the ( 0 + 1)-dimensional limit , where it leads to the schrdinger - newton equations . gravity is encoded here into a universal nonlinear extension of quantum theory .
the probabilistic interpretation , i.e. born s rule , holds provided the underlying model has only dimensionless parameters . .
And you have already written the first three sentences of the full article: linearity of the ( functional ) schrdinger equation and the validity of the superposition principle have been essential ingredients of quantum ( field ) theory since its earliest days .
practically all physical phenomena behave nonlinearly when examined over a sufficiently large range of the dynamical parameters that determine their evolution .
what singles out the linear dynamics for the wave function(al ) ?.
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quantum mechanics has been tested experimentally under a wide range of laboratory conditions and confirmed in all known cases .
yet the mathematical structure of the theory , so far , hinges heavily on its linearity embodied in linear operators acting on states represented by rays in a hilbert space @xcite .
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Suppose that you have an abstract for a scientific paper: we investigate the @xmath0 violating form factor of the @xmath1 and @xmath2 vertices in the pair production of @xmath3 bosons .
useful observables in azimuthal distributions are constructed to probe @xmath0 nonconservation which may originate from these vertices .
a simple two higgs model of @xmath0 violation is used as an illustration . in the near future , with the availability of experimental data at energy around the electroweak breaking scale , one expects to learn about the structure of the cubic and quartic self - interactions of gauge bosons .
so far , these interactions have not been directly tested in any experiments .
one exciting possibility is that such interactions will give new insights on @xmath0 violation , whose physical origin has not been understood with satisfaction yet .
the observation of @xmath0 violation in the kaon system can be explained in various ways within the framework of gauge theories , and choosing between them requires additional observation of @xmath0 violation . with this in mind , it is interesting to look for @xmath0 violating signals which may be induced by the self - interactions of gauge bosons .
we discuss here one such possibility , where the coupling of three neutral gauge bosons has a @xmath0 violating term in it .
we first did a model - independent discussion based on the most general form factors .
then a simple model , the two higgs doublet model , is used as an illustration of how the form factors may arise in a realistic @xmath0 violating theory . .
And you have already written the first three sentences of the full article: such @xmath0-odd term is indeed allowed in general on fundamental grounds , as is obvious from the general parametrization of the cubic coupling of gauge bosons @xcite .
most theoretical studies along this direction have been done@xcite only for the process @xmath4 .
the effect of @xmath0 violation in @xmath5 has not been thoroughly carried through@xcite and there is a need of detailed analysis ..
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this motivates us to perform a careful model - independent study . in section iv
, a simple two higgs model is used as an illustration .
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Suppose that you have an abstract for a scientific paper: we propose a simple method by which we can explain the magnetic - field dependence of the longitudinal ultrasonic attenuation in a type - ii superconductor .
it gives a curve which is in good agreement with experimental data , in paticular , near the lower critical field @xmath0 .
we compare it with conventional methods , which is not in good agreement with the experimental data near @xmath0 but near the upper critical field @xmath1 .
vortex , ultrasonic attenuation , magnetic - field 74.25.ld , 74.60.ec .
And you have already written the first three sentences of the full article: the temperature dependence of the ultrasonic attenuation in a superconductor is well described by the bcs theory @xcite . according to the bcs theory ,
the longitudinal ultrasonic attenuation coefficient in the superconducting state relative to that in the normal state is given by @xmath2 + 1 } .
\label{eqn:1}\ ] ] the energy gap parameter @xmath3 depends on the temperature . however , the magnetic - field dependence has not been explained very well ..
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et al . _ performed an experiment about the magnetic - field dependence of the longitudinal ultrasonic attenuation in the mixed state of pure niobium @xcite . and they explained it theoretically .
the spatial average of the energy gap , @xmath4 , was introduced and assumed to be proportional to the root mean square of the order parameter
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12,725 |
Suppose that you have an abstract for a scientific paper: the geometric and algebraic properties of gray categories with duals are investigated by means of a diagrammatic calculus .
the diagrams are three - dimensional stratifications of a cube , with regions , surfaces , lines and vertices labelled by gray category data .
these can be viewed as a generalisation of ribbon diagrams .
the gray categories present two types of duals , which are extended to functors of strict tricategories with natural isomorphisms , and correspond directly to symmetries of the diagrams .
it is shown that these functors can be strictified so that the symmetries of a cube are realised exactly .
a new condition on gray categories with duals called the spatial condition is defined .
we exhibit a class of diagrams for which the evaluation for spatial gray categories is invariant under homeomorphisms .
this relation between the geometry of the diagrams and structures in the gray categories proves useful in computations and has potential applications in topological quantum field theory . .
And you have already written the first three sentences of the full article: the aim of this paper is to develop the theory of duals for gray categories .
the principal tool is a diagrammatic calculus introduced in this paper .
this can be viewed as a higher - categorical , three - dimensional analogue of the diagrams used for computations in pivotal categories ..
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many of the algebraic results on gray categories with duals can be understood in terms of the geometry of the corresponding diagrams .
our main motivation are the applications of higher categories in ( extended ) topological quantum field theory , quantum geometry and conformal field theory @xcite .
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Suppose that you have an abstract for a scientific paper: we establish ahlswede dichotomy for arbitrarily varying classical - quantum wiretap channels .
this means that either the deterministic secrecy capacity of an arbitrarily varying classical - quantum wiretap channel is zero or it equals its randomness assisted secrecy capacity .
we analyze the secrecy capacity of arbitrarily varying classical - quantum wiretap channels when the sender and the receiver use various resources .
it turns out that having randomness , common randomness , and correlation as resources are very helpful for achieving a positive deterministic secrecy capacity of arbitrarily varying classical - quantum wiretap channels .
we prove the phenomenon `` super - activation '' for arbitrarily varying classical - quantum wiretap channels , i.e. , if we use two arbitrarily varying classical - quantum wiretap channels , both with zero deterministic secrecy capacity together , they allow perfect secure transmission . .
And you have already written the first three sentences of the full article: the developments in modern communication systems are rapid , especially quantum communication systems which set new kinds of limitations and offer new possibilities .
channel robustness and security are two of the basic features of many information processing systems , since many modern communication systems are often not perfect , but are vulnerable to jamming and eavesdropping .
there is already work done in the security of quantum information transmission using quantum key distributions ( cf ..
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@xcite and @xcite for two well - known examples ) .
but our goal is to have a more general theory for channel robustness and security in quantum information theory , i.e. message transmission should be secure against every possible kind of jamming and eavesdropping . furthermore , we are interested in asymptotic behavior when we deliver a large volume of messages by many channel uses .
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Suppose that you have an abstract for a scientific paper: we report the results of a search for an emission line from radiatively decaying dark matter in the _ chandra _ x - ray observatory spectrum of the ultra - faint dwarf spheroidal galaxy willman 1 .
99% confidence line flux upper limits over the 0.4 - 7 kev _
chandra _
bandpass are derived and mapped to an allowed region in the sterile neutrino mass - mixing angle plane that is consistent with recent constraints from _ suzaku _ x - ray observatory and _ chandra _ observations of the ursa minor and draco dwarf spheroidals .
a significant excess to the continuum , detected by fitting the particle - background - subtracted source spectrum , indicates the presence of a narrow emission feature with energy @xmath0 kev and flux @xmath1\times 10^{-6}\ { \rm photons}\ { \rm cm}^{-2}\ { \rm s}^{-1}$ ] at 68% ( 90% ) confidence . interpreting this as an emission line from sterile neutrino radiative decay
, we derive the corresponding allowed range of sterile neutrino mass and mixing angle using two approaches .
the first assumes that dark matter is solely composed of sterile neutrinos , and the second relaxes that requirement .
the feature is consistent with the sterile neutrino mass of @xmath2 kev and a mixing angle in a narrow range for which neutrino oscillations can produce all of the dark matter and for which sterile neutrino emission from the cooling neutron stars can explain pulsar kicks , thus bolstering both the statistical and physical significance of our measurement . .
And you have already written the first three sentences of the full article: none of the standard model particles can account for the dark matter that makes up most of the mass in the universe .
we report the latest results of a search for dark matter in the form of relic sterile neutrinos ( see kusenko 2009 for an up - to - date review ) .
the motivation for considering the sterile neutrino , one of a number of feasible dark - matter candidates , is two - fold ..
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first , the discovery of ordinary neutrino masses is most easily accommodated by means of the so - called seesaw mechanism , which calls for some new gauge - singlet fermions .
if all of these fermions have very large majorana masses , there are no additional degrees of freedom ( particles ) at the low energy scale . however
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12,728 |
Suppose that you have an abstract for a scientific paper: we consider a two dimensional electron system in an external magnetic field at and near an even denominator landau level filling fraction .
using a fermionic chern
simons approach we study the description of the system s low energy excitations within an extension of landau s fermi liquid theory .
we calculate perturbatively the effective mass and the quasi particle interaction function characterizing this description .
we find that at an even denominator filling fraction the fermion s effective mass diverges logarithmically at the fermi level , and argue that this divergence allows for an _ exact _ calculation of the energy gaps of the fractional quantized hall states asymptotically approaching these filling fractions .
we find that the quasi
particle interaction function approaches a delta function .
this singular behavior leads to a cancelation of the diverging effective mass from the long wavelength low frequency linear response functions at even denominator filling fractions . .
And you have already written the first three sentences of the full article: the fermionic chern simons theory has been extensively used in the last few years to describe the physics of a two dimensional electron gas in a partially filled landau level @xcite @xcite . in that theory , the problem of electrostatically interacting electrons in a strong magnetic field is converted , using an exact transformation , to a problem of electrostatically interacting `` transformed fermions '' which also interact with a chern simons gauge field .
being still unsolvable , the transformed fermion problem is studied by approximations .
the simplest approximation , mean field theory , already gives interesting physical results ..
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for example , it predicts the existence of stable quantized hall states at filling fractions of the form @xmath0 , where @xmath1 is an arbitrary integer , and @xmath2 is an even positive integer , equal to the number of quanta of chern simons flux attached to each fermion . as was first noted by jain @xcite ,
filling fractions of the above form , with @xmath3 , are the most prominent fractional hall states seen in the lowest landau level .
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Suppose that you have an abstract for a scientific paper: let @xmath0 denote the uniform model of random @xmath1-regular @xmath2-uniform hypergraphs on @xmath3 vertices , where @xmath2 is a fixed constant and @xmath4 may grow with @xmath3 .
an @xmath5-_overlapping _ hamilton cycle is a hamilton cycle in which successive edges overlap in precisely @xmath5 vertices , and 1-overlapping hamilton cycles are called _ loose _ hamilton cycles .
when @xmath6 are fixed integers , we establish a threshold result for the property of containing a loose hamilton cycle .
this partially verifies a conjecture of dudek , frieze , ruci ' nski and ileikis ( 2015 ) . in this setting
, we also find the asymptotic distribution and expected value of the number of loose hamilton cycles in @xmath0 .
finally we prove that for @xmath7 and for @xmath1 growing moderately as @xmath8 , the probability that @xmath0 has a @xmath5-overlapping hamilton cycle tends to zero . .
And you have already written the first three sentences of the full article: a _ hypergraph _ @xmath9 consists of a finite set @xmath10 of vertices and a multiset @xmath11 of multisubsets of @xmath10 , which we call edges .
we say that @xmath12 is _ simple _ if @xmath11 is a set of sets : that is , there are no repeated edges and no edge contains a repeated vertex .
given a fixed integer @xmath13 , the hypergraph @xmath14 is said to be @xmath2-_uniform _ if every edge contains precisely @xmath2 vertices , counting multiplicities ..
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uniform hypergraphs have been well - studied , as they generalise graphs ( which are 2-uniform hypergraphs ) .
let @xmath15 be an integer .
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Suppose that you have an abstract for a scientific paper: random - effects models are frequently used to synthesise information from different studies in meta - analysis .
while likelihood - based inference is attractive both in terms of limiting properties and in terms of implementation , its application in random - effects meta - analysis may result in misleading conclusions , especially when the number of studies is small to moderate .
the current paper shows how methodology that reduces the asymptotic bias of the maximum likelihood estimator of the variance component can also substantially improve inference about the mean effect size .
the results are derived for the more general framework of random - effects meta - regression , which allows the mean effect size to vary with study - specific covariates .
keywords : _ bias reduction ; heterogeneity ; meta - analysis ; penalized likelihood ; random effects ; restricted maximum likelihood _ = 1 .
And you have already written the first three sentences of the full article: meta - analysis is a widely applicable approach to combine information from different studies about a common effect of interest .
a popular framework for accounting for the heterogeneity between studies is the random - effects specification in @xcite .
there is ample evidence that frequentist inference for this specification can result in misleading conclusions , especially if inference is carried out by relying on first - order asymptotic arguments in the common setting of small or moderate number of studies ( e. g. , * ? ? ?.
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* ; * ? ? ?
the same considerations apply to the random - effects meta - regression model , which is a direct extension of random - effects meta - analysis allowing for study - specific covariates .
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Suppose that you have an abstract for a scientific paper: we demonstrate that a tensor product structure and optical analogy of quantum entanglement can be obtained by introducing pseudorandom phase sequences into classical fields with two orthogonal modes . using the classical analogy ,
we discuss efficient simulation of several typical quantum states , including product state , bell states , ghz state , and w state . by performing quadrature demodulation scheme ,
we propose a sequence permutation mechanism to simulate certain quantum states and a generalized gate array model to simulate quantum algorithm , such as shor s algorithm and grover s algorithm .
the research on classical simulation of quantum states is important , for it not only enables potential beyond quantum computation , but also provides useful insights into fundamental concepts of quantum mechanics . .
And you have already written the first three sentences of the full article: it has been widely known that fast algorithm is not available for many famous computing problems according to classical computational complexity theory @xcite .
quantum computation , however , enormously promotes computational efficiency with accumulation of computational complexity no faster than polynomial rate under linear increasement of input size by using several basic and purely physical features of quantum mechanics , such as coherent superposition , parallelism , entanglement , measurement collapse etc . @xcite .
the acceleratory ability of quantum computation is related to tensor product and quantum entanglement , of which the latter one is essential to realize quantum computation and quantum communication jozsa , braunstein . yet quantum algorithm is difficult to be realized for restrict of quantum system controllability , decoherence property and measurement randomness @xcite ..
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recently , several researches have proposed a new concept of realization of classical entanglement based on classical optical fields by introducing a new freedom degree to realize tensor product in quantum entanglement toppel .
further , ref .
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Suppose that you have an abstract for a scientific paper: the * * ka**rlsruhe * * tri**tium * * n**eutrino ( katrin ) experiment is a next generation , model independent , large scale experiment to determine the neutrino mass by investigating the kinematics of tritium beta - decay with a sensitivity of 200 mev / c@xmath0 .
the measurement setup consists of a high luminosity windowless gaseous molecular tritium source ( wgts ) , a differential and cryogenic pumped electron transport and tritium retention section , a tandem spectrometer section ( pre - spectrometer and main spectrometer ) for energy analysis , followed by a detector system for counting transmitted beta - decay electrons . to achieve the desired sensitivity
, the wgts , in which tritium decays with an activity of about 10@xmath1 bq , needs to be stable on the 0.1 % level in injection pressure and temperature at an absolute value of about 30 k. with the capability to create an axial magnetic field of 3.6 t the wgts is going to be one of the world s most complex superconducting magnet and cryostat systems .
the main spectrometer ( length 24 m , diameter 10 m ) , which works as a retarding electrostatic spectrometer , will have an energy resolution of 0.93 ev at 18.6 kev .
for the precise energy analysis at the tritium endpoint , a retarding potential of -18.6 kv is needed with 1 ppm stability . to reach the background level needed to achieve the sensitivity ,
it will be operated at a pressure of 10@xmath2 mbar .
this article will give an overview of the katrin experiment and its current status . .
And you have already written the first three sentences of the full article: neutrinos have broad implications for particle physics and cosmology in particular with regard to their absolute mass scale . due to their large abundance (
the neutrino density of the universe is 336 @xmath3 s @xmath4 for all three flavors ) they affect the evolution of gravitational clustering depending on their mass .
neutrino oscillation experiments imply that neutrinos are massive and set a lower limit of 40 mev / c@xmath0 @xcite on the neutrino mass ..
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experiments investigating the kinematics of @xmath5-decay on the other hand set an upper limit on the neutrino mass of 2.3 ev / c@xmath0 @xcite .
the attempts to determine the absolute neutrino mass from cosmological data strongly depend on the chosen data set and model .
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Suppose that you have an abstract for a scientific paper: hybrids of graphene and two dimensional transition metal dichalcogenides ( tmdc ) have the potential to bring graphene spintronics to the next level .
as we show here by performing first - principles calculations of graphene on monolayer mos@xmath0 , there are several advantages of such hybrids over pristine graphene .
first , dirac electrons in graphene exhibit a giant global proximity spin - orbit coupling , without compromising the semimetallic character of the whole system at zero field . remarkably , these spin - orbit effects can be very accurately described by a simple effective hamiltonian .
second , the fermi level can be tuned by a transverse electric field to cross the mos@xmath0 conduction band , creating a system of coupled massive and massles electron gases . both charge and spin transport in such systems
should be unique .
finally , we propose to use graphene / tmdc structures as a platform for optospintronics , in particular for optical spin injection into graphene and for studying spin transfer between tmdc and graphene .
graphene spintronics @xcite has relied exclusively on electrical spin injection @xcite .
combining graphene with semiconducting two - dimensional tdmc @xcite can open new venues for spintronics applications @xcite .
indeed , tmdc are becoming increasingly popular in optoelectronics as sensitive photodetectors @xcite or , forming lateral heterostructures @xcite , as two - dimensional solar cells @xcite .
important , tmdc have a sizeable spin - orbit coupling and lack space inversion symmetry . as a result
, their band structure @xcite allows for a valley resolved optical spin excitation by circularly polarized light @xcite .
tmdc can thus facilitate optical spin injection into graphene , in hybrid structures .
efficient growth of mos@xmath0 on graphene has already been demonstrated @xcite .
it was reported that graphene on mos@xmath0 is ultraflat , having large mean free paths @xcite ; angle - resolved photoemission found an intact dirac point....
And you have already written the first three sentences of the full article: structural relaxation and electronic structure calculations were performed with quantum espresso @xcite , using norm conserving pseudopotentials with kinetic energy cutoff of 60 ry for wavefunctions . for the exchange - correlation potential we used generalized gradient approximation @xcite .
the supercell containing a @xmath2 supercell of mos@xmath0 and @xmath3 supercell of graphene was embeded in a slab geometry with vacuum of about 13 , with a dipole correction @xcite , which is crucial to get accurate band offsets between the dirac point and the conduction band minimum of mos@xmath0 .
the resulting structure has a lattice mismatch of 2.8% which we split equally between graphene and mos@xmath0 by compressing graphene and stretching mos@xmath0 by 1.4% ..
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the supercell has 59 atoms .
the reduced brillouin zone was sampled with @xmath53 k points .
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12,734 |
Suppose that you have an abstract for a scientific paper: this paper assesses the accuracy and convergence of the linear - elastic , bond - based peridynamic model with brittle failure , known as the prototype micro - brittle ( pmb ) model .
we investigate the discrete equations of this model , suitable for numerical implementation .
it is shown that the widely used discretization approach incurs rather large errors .
motivated by this observation , a correction is proposed , which significantly increases the accuracy by cancelling errors associated with the discretization . as an additional result , we derive equations to treat the interactions between differently sized particles , i.e. , a non - homogeneous discretization spacing .
this presents an important step forward for the applicability of the pmb model to complex geometries , where it is desired to model interesting parts with a fine resolution ( small particle spacings ) and other parts with a coarse resolution in order to gain numerical efficiency .
validation of the corrected peridynamic model is performed by comparing longitudinal sound wave propagation velocities with exact theoretical results .
we find that the corrected approach correctly reproduces the sound wave velocity , while the original approach severely overestimates this quantity .
additionally , we present simulations for a crack growth problem which can be analytically solved within the framework of linear elastic fracture mechanics theory .
we find that the corrected peridynamics model is capable of quantitatively reproducing crack initiation and propagation .
meshless , simulation , peridynamics , crack growth .
And you have already written the first three sentences of the full article: peridynamics ( pd ) , originally devised in 1999 by s. a. silling @xcite is is a relatively new approach to solve problems in solid mechanics .
in contrast to the most popular numerical methods for solving continuum mechanics problems , namely the finite element method or the finite volume method , pd does not require a topologically connected mesh of elements .
additionally , pd incorporates the description of damage and material failure from the outset . within the context of mesh - free methods.
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, peridynamics can be classified as a total - lagrangian collocation method with nodal integration .
pd features two classes of interaction models , so called bond - based materials and state - based materials . in the bond - based case , interactions exist as spring - like forces between pairs of particles .
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12,735 |
Suppose that you have an abstract for a scientific paper: we review the properties of energetic parton propagation in hot or cold qcd matter , as obtained in recent works .
advances in understanding the energy loss - collisional and radiative - are summarized , with emphasis on the latter : it features very interesting properties which may help to detect the quark - gluon plasma produced in heavy ion collisions .
we describe two different theoretical approaches , which lead to the same radiated gluon energy spectrum .
the case of a longitudinally expanding qcd plasma is investigated .
the energy lost by a jet with given opening angle is calculated in view of making predictions for the suppression ( quenching ) of hard jet production .
phenomenological implications for the difference between hot and cold matter are discussed .
numerical estimates of the loss suggest that it may be significantly enhanced in hot compared to cold matter .
# 1 [ # 1]@xmath0 qcd , dense nuclear matter , quark - gluon plasma , gluon radiation , energy loss , relativistic heavy ion collisions .
And you have already written the first three sentences of the full article: over the past few years , a lot of work has been devoted to the propagation of high energy partons ( jets ) through hot and cold qcd matter .
the jet @xmath1-broadening and the gluon radiation induced by multiple scattering , together with the resulting radiative energy loss of the jet have been studied .
these studies are extensions to qcd of the analogous qed problem considered long ago by landau , pomeranchuk and migdal @xcite ..
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recent measurements @xcite ( reviewed in @xcite ) confirm the theoretical predictions in the qed case to good accuracy .
as in qed , coherent suppression of the radiation spectrum takes place when a parton propagates in a qcd medium .
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12,736 |
Suppose that you have an abstract for a scientific paper: cosmic rays produced in cluster accretion and merger shocks provide pressure to the intracluster medium ( icm ) and affect the mass estimates of galaxy clusters . although direct evidence for cosmic - ray ions in the icm is still lacking , they produce @xmath0-ray emission through the decay of neutral pions produced in their collisions with icm nucleons .
we investigate the capability of the _ gamma - ray large area space telescope ( glast ) _ and imaging atmospheric erenkov telescopes ( iacts ) for constraining the cosmic - ray pressure contribution to the icm .
we show that _ glast _ can be used to place stringent upper limits , a few per cent for individual nearby rich clusters , on the ratio of pressures of the cosmic rays and thermal gas .
we further show that it is possible to place tight ( @xmath1 ) constraints for distant ( @xmath2 ) clusters in the case of hard spectrum , by stacking signals from samples of known clusters .
the _
glast _ limits could be made more precise with the constraint on the cosmic - ray spectrum potentially provided by iacts .
future @xmath0-ray observations of clusters can constrain the evolution of cosmic - ray energy density , which would have important implications for cosmological tests with upcoming x - ray and sunyaev - zeldovich effect cluster surveys .
[ firstpage ] galaxies : clusters : general cosmology : miscellaneous cosmic rays radiation mechanisms : non - thermal gamma - rays : theory . .
And you have already written the first three sentences of the full article: clusters of galaxies are potentially powerful observational probes of dark energy , the largest energy budget in the universe causing the cosmic acceleration ( e.g. , * ? ? ?
* ; * ? ? ?
most of the cosmological applications using clusters rely on the estimates of their total virial mass quantity which is difficult to measure accurately in observations ..
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clusters offer a rich variety of observable properties , such as x - ray luminosity and temperature ( e.g. , * ? ? ?
* ) , sunyaev - zeldovich effect ( sze ) flux ( e.g. , * ? ? ?
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12,737 |
Suppose that you have an abstract for a scientific paper: the wake flow around a circular cylinder at @xmath0 performing rotatory oscillations has been thoroughly discussed in the literature , mostly focusing on the modifications to the natural bnard - von krmn vortex street that result from the forced shedding modes locked to the rotatory oscillation frequency .
the usual experimental and theoretical frameworks at these reynolds numbers are quasi - two - dimensional , since the secondary instabilities bringing a three - dimensional structure to the cylinder wake flow occur only at higher reynolds numbers . in the present paper
we show that a three - dimensional structure can appear below the usual three - dimensionalization threshold , when forcing with frequencies lower than the natural vortex shedding frequency , at high amplitudes , as a result of a previously unreported mechanism : a pulsed centrifugal instability of the oscillating stokes layer at the wall of the cylinder .
the present numerical investigation lets us in this way propose a physical explanation for the turbulence - like features reported in the recent experimental study of @xcite . .
And you have already written the first three sentences of the full article: a circular cylinder performing rotational oscillations around its axis in an infinite viscous fluid produces an axisymmetric pulsed boundary layer , called a stokes layer .
this is a flow susceptible to generate centrifugal instabilities .
the linear stability problem of this flow configuration has been studied by @xcite using asymptotic methods ..
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a threshold for the appearance of three - dimensional ( 3d ) axisymmetric instability modes was determined .
@xcite did also stability calculations not directly on the stokes layer problem but considering the modulated circular couette flow under axisymmetric disturbances , in the narrow - gap limit .
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12,738 |
Suppose that you have an abstract for a scientific paper: we investigate even - even two - proton borromean systems at prominent intermediate heavy waiting points for the rapid proton capture process .
the most likely single - particle levels are used to calculate three - body energy and structure as a function of proton - core resonance energy .
we establish a linear dependence between two- and three - body energies with the same slope , but the absolute value slightly dependent on partial wave structure . using these relations we estimate low - lying excited states in the isotones following the critical waiting points .
the capture rate for producing a borromean bound state is described based on a full three - body calculation for temperatures about @xmath0 gk . in addition , a simple rate expression , depending only on a single resonance state , is found to comply with the three - body calculation for temperatures between @xmath1 and @xmath2 gk .
the rate calculations are valid for both direct and sequential capture paths . as a result
the relevant path of the radiative capture reactions can be determined .
we present results for @xmath3 and @xmath4 photon emission , and discuss occurrence preferences in general as well as relative sizes of these most likely processes .
finally , we present a method for estimating proton capture rates in the region around the critical waiting points . .
And you have already written the first three sentences of the full article: a number of proton dripline nuclei are of particular interest as waiting points in the rapid - proton capture ( rp ) process expected to be active in the accretion of a close binary system containing a neutron star and resulting in an x - ray burst @xcite .
when the proton binding energy becomes negative at the dripline another proton is needed to produce the borromean system ( a bound system with unbound subsystems ) .
the effective lifetime of the critical waiting points in a stellar environment is a central quantity in the understanding of this astrophysical process ..
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this depends crucially on both proton binding of the waiting point plus one and two protons , as well as the reaction rate forming these nuclei @xcite .
the current estimates still result in an uncertainty in the effective lifetime of several orders of magnitude @xcite .
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12,739 |
Suppose that you have an abstract for a scientific paper: there is a common need in astroparticle experiments such as direct dark matter detection , double beta decay without emission of neutrinos @xmath0@xmath1@xmath2 $ ] and coherent neutrino nucleus scattering experiments for light detectors with a very low energy threshold . by employing the neganov - trofimov - luke effect ,
the thermal signal of particle interactions in a semiconductor absorber operated at cryogenic temperatures , can be amplified by drifting the photogenerated electrons and holes in an electric field .
this technology is not used in current experiments , in particular because of a reduction of the signal amplitude with time which is due to trapping of the charges within the absorber .
we present here the first results of a novel type of neganov - trofimov - luke effect light detector with an electric field configuration designed to improve the charge collection within the semiconductor . .
And you have already written the first three sentences of the full article: bolometers represent a key technology in rare event experiments like direct dark matter search and @xmath1 search . these experiments operate detectors at cryogenic temperatures to measure phonon - mediated signals .
the threshold within these experiments is crucial .
the neganov - trofimov - luke effect@xcite ( ntle ) can decrease the threshold of bolometric light detectors down to a few optical / uv photons . in @xmath1 experiments , this would allow to tag the cherenkov light emitted by @xmath1 events and reject completely the dominant @xmath3 background , which is below the cherenkov threshold emission . the rejection of the alpha background is necessary to extend the sensitivity of a bolometric experiment over the entire inverted hierarchy region of the neutrino mass pattern@xcite ..
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these light detectors can also enhance the sensitivity of dark matter searches@xcite based on scintillating crystals by increasing the discrimination between signal and background events . in the context of direct dark matter searches , lowering the threshold represents a dramatic improvement of the sensitivity .
this is particularly true for low mass wimps where the results of the experiments are currently characterised by contradictions between positive hints of a signal and total exclusion@xcite . due to the ntle
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12,740 |
Suppose that you have an abstract for a scientific paper: the strong dependence of the mass variance parameter , @xmath0 , on the adopted cluster mass - temperature relation is explored .
a recently compiled x - ray cluster catalog and various mass - temperature relations are used to derive the corresponding values of @xmath0 .
calculations of the power spectrum of the cmb anisotropy induced by the sunyaev - zeldovich effect and cluster number counts are carried out in order to assess the need for a consistent choice of the mass - temperature scaling and the parameter @xmath0 .
we find that the consequences of inconsistent choice of the mass - temperature relation and @xmath0 could be quite substantial , including a considerable mis - estimation of the magnitude of the power spectrum and cluster number counts .
our results can partly explain the large scatter between published estimates of the power spectrum and number counts .
we also show that the range of values of the power - law index in the scaling @xmath1 deduced in previous studies is likely overestimated ; we obtain a more moderate dependence , @xmath2 .
cosmology , cmb , clusters of galaxies 98.65.cw,98.70.vc,98.65.hb .
And you have already written the first three sentences of the full article: calculations of the power spectrum of cmb anisotropy induced by the sunyaev - zeldovich ( s - z ) effect , and of cluster number counts , involve various intrinsic cluster quantities , as well as cosmological and cluster mass function parameters .
specifically , the level of s - z signal in a cluster is directly related to the intracluster ( ic ) gas temperature and density distributions .
the cosmological and large scale structure parameters enter in the expression for the collective mass function of clusters ..
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most commonly , this function is assumed to have the press & schechter ( 1974 ) form , but other , more physically established mass functions , are also widely adopted . the mass function is usually normalized by specifying an observationally deduced value of @xmath0 , the rms density fluctuation on a scale of @xmath3 mpc .
the value of @xmath0 may be deduced in several different ways , perhaps most directly from a comparison between the observed two - point correlation function of galaxies or clusters of galaxies , and the spectrum of the primordial density fluctuation field on the relevant scales , recently employed in the analysis of the large sdss sample ( , tegmark 2003 ) .
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12,741 |
Suppose that you have an abstract for a scientific paper: results of realistic simulations of solar surface convection on the scale of supergranules ( 96 mm wide by 20 mm deep ) are presented .
the simulations cover only 10% of the geometric depth of the solar convection zone , but half its pressure scale heights .
they include the hydrogen , first and most of the second helium ionization zones .
the horizontal velocity spectrum is a power law and the horizontal size of the dominant convective cells increases with increasing depth .
convection is driven by buoyancy work which is largest close to the surface , but significant over the entire domain .
close to the surface buoyancy driving is balanced by the divergence of the kinetic energy flux , but deeper down it is balanced by dissipation .
the damping length of the turbulent kinetic energy is 4 pressure scale heights .
the mass mixing length is 1.8 scale heights .
two thirds of the area is upflowing fluid except very close to the surface .
the internal ( ionization ) energy flux is the largest contributor to the convective flux for temperatures less than 40,000 k and the thermal energy flux is the largest contributor at higher temperatures .
this data set is useful for validating local helioseismic inversion methods .
sixteen hours of data are available as four hour averages , with two hour cadence , at steinr.msu.edu/@xmath0bob/96averages , as idl save files .
the variables stored are the density , temperature , sound speed , and three velocity components .
in addition , the three velocity components at 200 km above mean continuum optical depth unity are available at 30 sec .
cadence . .
And you have already written the first three sentences of the full article: solar surface convection on supergranular scales ( 96 mm wide by 20 mm deep ) was simulated by solving the conservation equations for mass , momentum and internal energy .
spatial derivatives were evaluated using sixth order finite differences @xcite and the time advance was by a low memory , third order runge - kutta scheme @xcite .
the calculations were performed on a grid of @xmath1 giving a resolution of 96 km horizontally and 12 - 70 km vertically ..
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f - plane rotation is included corresponding to a latitude of 30 . a tabular equation of state which includes local thermodynamic equilibrium ( lte ) ionization of the abundant elements as well as hydrogen molecule formation , was used to obtain the pressure and temperature as a function of log density and internal energy per unit mass .
the radiative heating / cooling was obtained by solving the radiation transfer equation in both continua and lines using the feautrier method , assuming local thermodynamic equilibrium ( lte ) .
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12,742 |
Suppose that you have an abstract for a scientific paper: eeg time series are analyzed using the diffusion entropy method .
the resulting eeg entropy manifests short - time scaling , asymptotic saturation and an attenuated alpha - rhythm modulation .
these properties are faithfully modeled by a phenomenological langevin equation interpreted within a neural network context . .
And you have already written the first three sentences of the full article: in the nearly one hundred years since the electroencephalogram ( eeg ) was introduced into neuroscience there have been a variety of methods used in attempts to establish a taxonomy of eeg patterns in order to delineate the correspondence between brain wave patterns and brain activity . over that time
the single channel eeg time series has been interpreted as consisting of relatively slow regular variations called _ signal _ and the relatively rapid erratic fluctuations called _ noise_. this separation implies that the signal contains information about the eeg channels in the brain , whereas the erratic fluctuations are a property of a channel s environment and does not contain any useful information .
recent studies have refined this engineering model and extracted information from the random fluctuations by concentrating on what is believed to be the scaling behavior of the time series ..
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analysis of the second moment of the single channel time series shows an algebraic scaling in time , i.e. , @xmath0 the brackets denote a suitably defined averaging procedure and detrended fluctuation analysis ( dfa ) @xcite , which measures the standard deviation of the detrended fluctuations , has been the method of choice for the recent analysis of eeg data @xcite .
buiatti et al .
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12,743 |
Suppose that you have an abstract for a scientific paper: two positive scalar curvature metrics @xmath0 , @xmath1 on a manifold @xmath2 are psc - isotopic if they are homotopic through metrics of positive scalar curvature .
it is well known that if metrics @xmath0 , @xmath1 of positive scalar curvature on a closed compact manifold @xmath2 are psc - isotopic , then they are psc - concordant : i.e. , there exists a metric @xmath3 of positive scalar curvature on the cylinder @xmath4 which extends the metrics @xmath0 on @xmath5 and @xmath1 on @xmath6 and is a product metric near the boundary .
the main result of the paper is that if psc - metrics @xmath0 , @xmath1 on @xmath2 are psc - concordant , then there exists a diffeomorphism @xmath7 with @xmath8 ( a pseudo - isotopy ) such that the metrics @xmath0 and @xmath9 are psc - isotopic . in particular , for a simply connected manifold @xmath2 with @xmath10 , psc - metrics @xmath0 , @xmath1 are psc - isotopic if and only if they are psc - concordant . to prove these results ,
we employ a combination of relevant methods : surgery tools related to the gromov - lawson construction , classic results on isotopy and pseudo - isotopy of diffeomorphisms , standard geometric analysis related to the conformal laplacian , and the ricci flow . in this article ,
the author provides full details of the proof of the concordance / isotopy problem .
the first published proof , @xcite , accomplished this task only partially since there was an error , see the erratum @xcite , which damaged the main argument of ( * ? ? ?
* theorem 2.9 ) , and , consequently , the proof of ( * ? ? ? * theorem a ) . .
And you have already written the first three sentences of the full article: let @xmath2 be a closed smooth manifold .
we denote by @xmath11 the space of all riemannian metrics on @xmath2 in the @xmath12-topology , and by @xmath13 the subspace of metrics @xmath14 with positive scalar curvature @xmath15 .
we use the abbreviation `` psc - metric '' for `` metric with positive scalar curvature '' . throughout the article.
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, it is assumed that @xmath2 admits a psc - metric , i.e. when @xmath16 .
it is worth to mention that the existence of psc - metrics is a well - studied question . in particular ,
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12,744 |
Suppose that you have an abstract for a scientific paper: this review is based on the talk presented at the susy 2012 ( beijing ) .
the new particle around 125 gev observed at the large hadron collider ( lhc ) is almost consistent with the standard model higgs boson , except that the diphoton decay mode may be excessive .
we summarize a number of possibilities . while at the lhc the dominant production mechanism for the higgs boson of the standard model and some other extensions is via the gluon fusion process
, the alternative vector - boson fusion is more sensitive to electroweak symmetry breaking . using the well known dijet - tagging technique to single out the vector - boson fusion mechanism , we investigate potential of vector - boson fusion to discriminate a number of models suggested to give an enhanced inclusive diphoton production rate . .
And you have already written the first three sentences of the full article: in this talk , we are going to summarize a few models that have been suggested to explain the newly observed particle of about 125 gev at the large hadron collider ( lhc ) @xcite .
it is of very high expectation that the observed particle is the long - sought higgs boson , which was proposed in 1960s @xcite . before the lhc era
there have been many speculations of the breaking of electroweak symmetry ( ewsb ) ..
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there are two known scales in particle physics the electroweak scale and the planck scale .
the fundamental higgs boson of order 100 gev is unstable against the radiative corrections .
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12,745 |
Suppose that you have an abstract for a scientific paper: approximate theories for the restricted primitive model electrolyte are compared in the light of totsuji s lower bound for the energy ( an improvement over onsager s ) , gillan s upper bound for the free energy , and thermal stability requirements .
theories based on the debye - hckel ( dh ) approach and the mean spherical approximation ( msa ) , including extensions due to bjerrum , ebeling , fisher and levin , and stell , zhou , and yeh ( pmsa1 , 2 , 3 ) are tested . in the range @xmath0 , all dh - based theories satisfy totsuji s bound , while the msa possesses a significant region of violation .
both dh and msa theories violate gillan s bound in the critical region and below unless ion pairing _ and _ the consequent free - ion depletion are incorporated
. however , the pmsa theories , which recognize pairing but not depletion , fail to meet the bound .
the inclusion of excluded - volume terms has only small effects in this respect .
finally , all the pairing theories exhibit negative constant - volume specific heats when @xmath1 ; this is attributable to the treatment of the association constant . 2 .
And you have already written the first three sentences of the full article: the liquid - gas phase transition in electrolytes is of current interest because of puzzling experiments and theoretical efforts to understand them . for recent reviews ,
see @xcite .
the primary model used is the restricted primitive model ( rpm ) consisting of two oppositely charged , but otherwise identical , sets of @xmath2 hard spheres of diameter @xmath3 and charge per particle @xmath4 , immersed in a medium of dielectric constant @xmath5 ( to represent the solvent ) and volume @xmath6 ..
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we will restrict our attention to the rpm in @xmath7 dimensions and use the reduced temperature and density @xmath8 where @xmath9 ; the debye inverse screening length , @xmath10 the reduced helmholtz free energy density @xmath11 and the reduced configurational energy per particle , @xmath12 , defined via @xmath13 where @xmath14 and @xmath15 denote the total free energy and ( internal ) energy .
recent theory@xcite has focussed on two approaches to approximating the free energy of the rpm , based on either debye - hckel ( dh ) theory@xcite or the mean spherical approximation ( msa)@xcite .
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12,746 |
Suppose that you have an abstract for a scientific paper: in this paper we rely on the quasar ( qso ) catalog of the sloan digital sky survey data release six ( sdss dr6 ) of about one million photometrically selected qsos to compute the integrated sachs - wolfe ( isw ) effect at high redshift , aiming at constraining the behavior of the expansion rate and thus the behaviour of dark energy at those epochs .
this unique sample significantly extends previous catalogs to higher redshifts while retaining high efficiency in the selection algorithm .
we compute the auto - correlation function ( acf ) of qso number density from which we extract the bias and the stellar contamination .
we then calculate the cross - correlation function ( ccf ) between qso number density and cosmic microwave background ( cmb ) temperature fluctuations in different subsamples : at high @xmath0 and low @xmath1 redshifts and for two different choices of qso in a conservative and in a more speculative analysis .
we find an overall evidence for a cross - correlation different from zero at the @xmath2 level , while this evidence drops to @xmath3 at @xmath0 .
we focus on the capabilities of the isw to constrain the behaviour of the dark energy component at high redshift both in the @xmath4cdm and early dark energy cosmologies , when the dark energy is substantially unconstrained by observations . at present ,
the inclusion of the isw data results in a poor improvement compared to the obtained constraints from other cosmological datasets .
we study the capabilities of future high - redshift qso survey and find that the isw signal can improve the constraints on the most important cosmological parameters derived from planck cmb data , including the high redshift dark energy abundance , by a factor @xmath5 . .
And you have already written the first three sentences of the full article: the cosmic microwave background ( cmb ) measurements of temperature anisotropies and polarization @xcite and the redshift - distance measurements of type ia supernovae ( snia ) at @xmath6 @xcite , have established that the universe is undergoing an accelerated phase of expansion and that its total energy budget is dominated by a dark energy component .
the nature of this component is still unknown and many observational probes have been proposed to test its properties and redshift evolution either in the standard @xmath4-cold dark matter ( @xmath4cdm ) , modified gravity or quintessence models ( for a review see ref .
while the cmb is a powerful cosmological probe of the universe at @xmath7 , the anisotropies present in cmb data ( kinetic and thermal sunyaev - zeldovich effects , weak lensing and the integrated sachs - wolfe effect ) contain precious information on the large scale structure that formed at much lower redshift ..
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these effects can be studied and detected by cross - correlating cmb data with tracers of the large scale structure ( lss ) such as galaxies or quasars . here
, we will focus on the integrated sachs - wolfe effect @xcite .
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12,747 |
Suppose that you have an abstract for a scientific paper: the discontinuous galerkin time - stepping method has many advantageous properties for solving parabolic equations .
however , it requires the solution of a large nonsymmetric system at each time - step .
this work develops a fully robust and efficient preconditioning strategy for solving these systems . drawing on parabolic inf - sup theory ,
we first construct a left preconditioner that transforms the linear system to a symmetric positive definite problem to be solved by the preconditioned conjugate gradient algorithm .
we then prove that the transformed system can be further preconditioned by an ideal block diagonal preconditioner , leading to a condition number bounded by @xmath0 for any time - step size , any approximation order and any positive - definite self - adjoint spatial operators .
numerical experiments demonstrate the low condition numbers and fast convergence of the algorithm for both ideal and approximate preconditioners , and show the feasibility of the high - order solution of large problems .
discontinuous galerkin ; time discretizations ; parabolic pde ; preconditioning ; conjugate gradient algorithm . .
And you have already written the first three sentences of the full article: the discontinuous galerkin ( dg ) time - stepping method is a single - step implicit scheme defined by a variational temporal discretization of parabolic evolution equations that generalizes the backward euler method to higher - order approximations @xcite . for an introduction to this time discretization scheme in the context of abstract parabolic problems ,
we refer the reader to @xcite . in certain cases ,
it coincides with the radau iia implicit runge kutta ( irk ) schemes and the subdiagonal pad approximations to the exponential function @xcite ..
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it can be coupled with standard spatial discretization schemes , such as finite difference , finite element or spectral methods ; in particular , when coupled to a spatial finite element method ( fem ) , it leads to a tensor - product space - time fem .
the dg time - stepping method features many advantages that make it an attractive choice for solving parabolic problems .
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12,748 |
Suppose that you have an abstract for a scientific paper: for a system with three identical atoms , the dependence of the @xmath0wave virtual state energy on the weakly bound dimer and trimer binding energies is calculated in a form of a universal scaling function .
the scaling function is obtained from a renormalizable three - body model with a pairwise dirac - delta interaction .
it was also discussed the threshold condition for the appearance of the trimer virtual state
. 0.5 cm .
And you have already written the first three sentences of the full article: weakly bound three - body zero - angular momentum states appear in a three boson system , with the number of states growing to infinity , condensing at zero energy as the pair interactions are just about to bind two particles in @xmath0wave .
these three - body states are known as efimov states @xcite .
their wave functions , loosely bound , extend far beyond those of normal states and dominate the low - energy scattering phenomena in these systems ..
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the efimov states have been studied in a number of model calculations @xcite , in atomic and nuclear systems , without yet a clear experimental signature of their occurrence @xcite .
actually , the search of efimov states in atomic systems is becoming more appealing , due to the experimental realization of bose - einstein condensation ( bec ) @xcite , and due to the possibility of altering the effective scattering length of the low - energy atom - atom interaction in the trap , from large negative to large positive values crossing the dimer zero binding energy value , by using an external magnetic field @xcite .
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12,749 |
Suppose that you have an abstract for a scientific paper: in this article , we have given a systematic formulation of the new generalized competing mechanism : the glauber - type single - spin transition mechanism , with probability @xmath0 , simulates the contact of the system with the heat bath , and the kawasaki - type spin - pair redistribution mechanism , with probability @xmath1 , simulates an external energy flux .
these two mechanisms are natural generalizations of glauber s single - spin flipping mechanism and kawasaki s spin - pair exchange mechanism respectively . on the one hand ,
the new mechanism is in principle applicable to arbitrary systems , while on the other hand , our formulation is able to contain a mechanism that just directly combines single - spin flipping and spin - pair exchange in their original form . _ _ compared with the conventional mechanism , the new mechanism does not assume the simplified version and leads to greater influence of temperature . the fact , order for lower temperature and disorder for higher temperature , will be universally true . in order to exemplify this difference , we applied the mechanism to @xmath2 ising model and obtained analytical results .
we also applied this mechanism to kinetic gaussian model and found that , above the critical point there will be only paramagnetic phase , while below the critical point , the self - organization as a result of the energy flux will lead the system to an interesting heterophase , instead of the initially guessed antiferromagnetic phase .
we studied this process in details .
[ theorem]acknowledgement [ theorem]algorithm [ theorem]axiom [ theorem]claim [ theorem]conclusion [ theorem]condition [ theorem]conjecture [ theorem]corollary [ theorem]criterion [ theorem]definition [ theorem]example [ theorem]exercise [ theorem]lemma [ theorem]notation [ theorem]problem [ theorem]proposition [ theorem]remark [ theorem]solution [ theorem]summary .
And you have already written the first three sentences of the full article: in recent years , there have been continuing efforts towards a clear picture of the self - organization phenomena in the phase transitions of magnetic systems .
most of the works@xcite have been concentrated on ising and ising - like systems , governed by two competing dynamics : glauber s single - spin flipping mechanism@xcite and kawasaki s spin - pair exchange mechanism@xcite , both with a probability .
the system is coupled to a heat bath at a given temperature while being subject to an external energy flux ..
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glauber s flipping mechanism is to simulate the contact of the system with the heat bath . changing the order parameter
, it favors lower system energy . on the other hand ,
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12,750 |
Suppose that you have an abstract for a scientific paper: the present work is based on the nonequilibrium perturbative formalism . there
the self - energies are derived up to the forth - order . in consequence
, it proves that the nonequilibrium ( real - time ) perturbative expansion can be connected with the matsubara imaginary - time perturbative expansion for equilibrium . as the numerical results
, the kondo resonance still disappears for bias voltage exceeding the kondo temperatures , as observed in experiments of two terminal systems .
nonequilibrium perturbative formalism , nonequilibrium green s function , kondo effect , dyson s equation 71.15.-m , 05.70.ln .
And you have already written the first three sentences of the full article: the basic idea on the nonequilibrium perturbation theory grounded on the time - contour which starts and ends at @xmath0 via @xmath1 has been proposed by schwinger .
@xcite after that , the frame of the nonequilibrium perturbation theory has been built up using the nonequilibrium green s functions given after the time - contour by keldysh .
@xcite the perturbative equation is expressed in matrix form : @xmath2 where @xmath3 , \ \ { \bf { \sigma}}=\left [ \begin{array } { ll}{\sigma}^{-- } & { \sigma}^ < \\ { \sigma}^ > & { \sigma}^{++ } \\ \end{array } \right ].
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. \nonumber \end{aligned}\ ] ] the nonequilibrium green s functions are given in the heisenberg representation by @xmath4 here , the time ordering operator @xmath5 arranges in chronological order and @xmath6 is the anti time ordering operator which arranges in the reverse of chronological order .
the angular brackets denote thermal average in nonequilibrium .
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Suppose that you have an abstract for a scientific paper: we report analytic solutions of a recently discovered quasi - exactly solvable model consisting of two electrons , interacting _ via _ a coulomb potential , but restricted to remain on the surface of a @xmath0-dimensional sphere .
polynomial solutions are found for the ground state , and for some higher ( @xmath1 ) states .
kato cusp conditions and interdimensional degeneracies are discussed . .
And you have already written the first three sentences of the full article: a quasi - exactly solvable model is one for which it is possible to solve the schrdinger equation exactly for a finite portion of the energy spectrum @xcite . in quantum chemistry ,
a famous example of this is the hooke s law atom @xcite , which consists of a pair of electrons , repelling coulombically but trapped in a harmonic external potential .
this model and others @xcite have been used extensively to test various approximations @xcite within density functional theory ( dft ) @xcite and explicitly correlated methods @xcite ..
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we have recently discovered @xcite that a pair electrons , repelling coulombically but constrained to remain on the surface of a @xmath0-sphere of radius @xmath2 @xcite is also quasi - exactly solvable and we have called this system @xmath0-spherium .
( we adopt the convention that a @xmath0-sphere is the surface of a ( @xmath3)-dimensional ball . )
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Suppose that you have an abstract for a scientific paper: the state spaces of machines admit the structure of time . a homotopy theory respecting
this additional structure can detect machine behavior unseen by classical homotopy theory . in an attempt to bootstrap classical tools into the world of abstract spacetime
, we identify criteria for classically homotopic , monotone maps of pospaces to _ future homotope _ , or homotope along homotopies monotone in both coordinates , to a common map .
we show that consequently , a hypercontinuous lattice equipped with its lawson topology is _ future contractible _ , or contractible along a future homotopy , if its underlying space has connected cw type . .
And you have already written the first three sentences of the full article: the state spaces of machines often admit partial orders which describe the causal relationship between states .
for example , the unit interval @xmath0 equipped with its standard total order represents the states of a finite , sequential process .
figure [ fig:2sem ] illustrates the state space @xmath1 of two sequential processes accessing a binary semaphore ..
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thinking of the upper corner as the desired end state , we view monotone paths @xmath2 reaching the striped zone as unsafe executions of our binary system , doomed never to terminate successfully .
we can thus articulate critical machine behavior in the language of partially ordered spaces . a homotopy theory respecting this additional structure of time
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12,753 |
Suppose that you have an abstract for a scientific paper: an entropy of the ising model in the mean field approximation is derived by the hamilton - jacobi formalism .
we consider a grand canonical ensemble with respect to the temperature and the external magnetic field .
a cusp arises at the critical point , which shows a simple and new geometrical aspect of this model . in educational sense
, this curve with a cusp helps students acquire a more intuitive view on statistical phase transitions . .
And you have already written the first three sentences of the full article: phase transitions , critical phenomena , and the corresponding critical exponents are fundamental topics in statistical mechanics .
though they should have a close relation with critical points of maps @xcite , catastrophe theory @xcite , and singularity theory @xcite in mathematics , there is little application to these simple physical problems . in these geometrical standpoints
, it is natural to expect critical points to be singularities on a certain surface or a curve . a critical phenomenon , accompanied by the hamilton - jacobi structure , is simply visualized in the present paper ..
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we take ising model in the mean field approximation as an example .
relations between thermodynamics and hamilton - jacobi theory have been discussed for many years @xcite .
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12,754 |
Suppose that you have an abstract for a scientific paper: young star clusters ( yscs ) appear to be a ubiquitous product of star formation in local galaxies , thus , they can be used to study the star formation process at work in their host galaxies .
moreover , yscs are intrinsically brighter that single stars , potentially becoming the most important tracers of the recent star formation history in galaxies in the local universe . in local galaxies
, we also witness the presence of a large population of evolved star clusters , commonly called globular clusters ( gcs ) .
gcs peak formation history is very close to the redshift ( @xmath02 ) when the cosmic star formation history reached the maximum .
therefore , gcs are usually associated to extreme star formation episodes in high - redshift galaxies .
it is yet not clear whether yscs and gcs share a similar formation process ( same physics under different interstellar medium conditions ) and evolution process , and whether the former can be used as progenitor analogs of the latter . in this invited contribution ,
i review general properties of ysc populations in local galaxies .
i will summarise some of the current open questions in the field , with particular emphasis to whether or not galactic environments , where yscs form , leave imprints on the nested populations .
the importance of this rapidly developing field can be crucial in understanding gc formation and possibly the galactic environment condition where this ancient population formed . .
And you have already written the first three sentences of the full article: yscs are usually identified as gravitationally bound stellar structures , with radii between 0.5 up to several parsecs and masses between @xmath1 and @xmath2 ( ) .
thanks to the hst spatial resolution and multiband coverage the ysc field has been continuously advancing .
yscs are easily observed in local galaxies which are able to sustain star formation ..
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this is not always true at the lowest star - forming regimes .
for example , in dwarf galaxies , star and cluster formation appears dominated by stochastic processes ( ( * ? ? ? * cook et al .
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12,755 |
Suppose that you have an abstract for a scientific paper: we discuss the diagnostic potential of high cadence ultraviolet spectral data when transient ionization is considered . for this
we use high cadence uv spectra taken during the impulsive phase of a solar flares ( observed with instruments on - board the _ solar maximum mission _ ) which showed excellent correspondence with hard x - ray pulses .
the ionization fraction of the transition region ion o v and in particular the contribution function for the o v 1371 line are computed within the atomic data and analysis structure , which is a collection of fundamental and derived atomic data and codes which manipulate them . due to transient ionization ,
the o v 1371 line is enhanced in the first fraction of a second with the peak in the line contribution function occurring initially at a higher electron temperature than in ionization equilibrium . the rise time and enhancement factor depend mostly on the electron density . the fractional increase in the o
v 1371 emissivity due to transient ionization can reach a factor of 24 and can explain the fast response in the line flux of transition regions ions during the impulsive phase of flares solely as a result of transient ionization .
this technique can be used to diagnostic the electron temperature and density of solar flares observed with the forth - coming interface region imaging spectrograph .
And you have already written the first three sentences of the full article: the solar atmosphere contains a range of highly dynamic features , e.g. flares , jets , spicules , etc . in order to fully observe these events , requires high cadence , high spatial and high spectral resolution instruments .
however , due to various scientific and technical considerations , trade - offs in the instrument design must be made by the investigators .
milli - second data is commonly acquired in the radio and hard x - rays frequencies , while at ultraviolet wavelengths , high cadence is generally not available with most ultraviolet spectrographs . the highest cadence uv spectrometer to date was the ultraviolet spectrometer and polarimeter ( uvsp ).
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which was flown on the _ solar maximum mission ( smm ) _ in the early 1980 s .
several flares were observed simultaneously in the uv at selected individual spectral lines , e.g. o v 1371 , si iv 1394 etc , and at hard x - ray energies of several kev .
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Suppose that you have an abstract for a scientific paper: studying the physical conditions of very low - luminosity objects ( vellos ; @xmath0 l@xmath1 ) is important for understanding the earliest evolutionary stage of protostars and brown dwarfs .
we report interferometric observations of the vello l1521f - irs , in line emission and the continuum emission , using the submillimeter array . with the high - resolution observations ,
we have spatially resolved a compact but poorly collimated molecular outflow associated with for the first time .
the blueshifted and redshifted lobes are aligned along the east and west side of with a lobe size of .
the estimated outflow mass , maximum outflow velocity , and outflow force are , 7.2 km s@xmath2 , and , respectively .
the estimated outflow parameters such as size , mass , and momentum rate are similar to values derived for other vellos , and are located at the lower end of values compared to previously studied outflows associated with low- to high - mass star forming regions .
low - velocity less collimated ( 1.5 km s@xmath2/1200 au ) and higher - velocity compact ( 4.0 km s@xmath2/920 au ) outflow components are suggested by the data
. these velocity structures are not consistent with those expected in the jet driven or wind driven outflow models , perhaps suggesting a remnant outflow from the fhsc as well as an undeveloped outflow from the protostar .
detection of an infrared source and compact millimeter continuum emission suggest the presence of the protostar , while its low bolometric luminosity ( 0.0340.07 l@xmath1 ) , and small outflow , suggests that l1521f is in the earliest protostellar stage ( @xmath3 yr ) and contains a substellar mass object .
the bolometric ( or internal ) luminosity of l1521f - irs suggests that the current mass accretion rate is an order - of - magnitude lower than expected in the standard mass accretion model ( @xmath410@xmath5 m@xmath1 yr@xmath2 ) , which may imply that l1521f - irs is currently in a low activity phase . .
And you have already written the first three sentences of the full article: studying the earliest phase of star formation is an important issue for understanding the initial conditions of star formation .
previous studies of star formation have focused on dense cores associated with protostars , whereas these class i/0 objects are rather well - developed protostars with estimated ages of . according to the conventional accretion scenario of protostars ( e.g. , stahler et al . 1980 ) , in which the accretion luminosity is given as ( @xmath6 is the gravitational constant , @xmath7 is the mass accretion rate , and @xmath8 and @xmath9 are the mass and the radius of the protostar , respectively ) , extremely young protostars in a very early phase of the accretion process are less luminous when compared with well - developed protostars .
such extremely young protostars , though their total number would be small because of their short time scale , have most probably not been identified in many previous studies . in order for us to study the initial conditions , or extremely early phase of star formation , it is crucial for us to pay more attention to starless cores , where no bright infrared sources are found ..
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starless cores with high central densities are sometimes called pre - stellar cores , as they show signs of evolution toward the formation of a protostar , such as inward motions ( e.g. , ; tafalla et al 1998 . ohashi et al .
1999 ) .
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12,757 |
Suppose that you have an abstract for a scientific paper: we study the phase transition in gauge - higgs unification at finite temperature .
in particular , we obtain the strong first order electroweak phase transition for a simple matter content yielding the correct order of higgs mass at zero temperature .
two stage phase transition is found for a particular matter content , which is the strong first order at each stage .
we further study supersymmetric gauge models with the scherk - schwarz supersymmetry breaking .
we again observe the first order electroweak phase transition and multi stage phase transition .
# 1|#1| # 1#1 # 1|#1 # 1| # 1.3ex riken - th-42 + ou - het-526/2005 + hep - th/0505066 * aspects of phase transition + in gauge - higgs unification at finite temperature * nobuhito maru@xmath0 , kazunori takenaga@xmath1 @xmath2 _ theoretical physics laboratory , riken , wako , saitama 351 - 0198 , japan _ + @xmath3 _ department of physics , osaka university , toyonaka , osaka 560 - 0043 , japan _ .
And you have already written the first three sentences of the full article: there has been paid much attention to the scenario of gauge - higgs unification @xcite@xcite for the possibility to solve the gauge hierarchy problem without supersymmetry ( susy ) . in this scenario ,
higgs fields are regarded as extra components in the original gauge field .
the higher dimensional local gauge invariance ensures that the higgs field is strictly massless ..
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if spatial coordinates are compactified , then the extra component gauge field behaves as the scalar field at low energies . and
the scalar field can develop the vacuum expectation values ( vev ) through the dynamics of the wilson line phases , which is called as the hosotani mechanism @xcite .
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Suppose that you have an abstract for a scientific paper: we report the results of the first transit timing variation ( ttv ) analysis of the very hot jupiter ogle - tr-132b , using ten transits collected over a seven - year period .
our analysis combines three previously published transit light curves with seven new transits , which were observed between february 2008 and may 2009 with the new magic - e2v instrument on the magellan telescopes in chile .
we provide a revised planetary radius of @xmath0 @xmath1 , which is slightly larger than , but consistent within the errors , of the previously published results .
analysis of the planet - to - star radius ratio , orbital separation , inclination and transit duration reveals no apparent variation in any of those parameters during the time span observed .
we also find no sign of transit timing variations larger than @xmath2 s , with most residuals very close to zero .
this allows us to place an upper limit of 5 - 10 @xmath3 for a coplanar , low - eccentricity perturber in either the 2:1 or 3:2 mean - motion resonance with ogle - tr-132b .
we similarly find that the data are entirely consistent with a constant orbital period and there is no evidence for orbital decay within the limits of precision of our data . .
And you have already written the first three sentences of the full article: precise timing of exoplanet transits over many years is a powerful technique to learn more about a planetary system .
transit timing variations , or ttvs , can arise from many potential scenarios , such as orbital precession , orbital decay , and perturbations by additional planets , small stellar companions , large moons or rings ; these effects have been modeled in numerous papers over the last decade @xcite .
recently , @xcite announced the first incontrovertible evidence of transit timing variations in the kepler-9 system , where a pair of saturn - mass planets are trapped in a 2:1 mean - motion resonance , producing strong , complementary deviations of over an hour in the midtimes of both transits ..
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other observational evidence is less clear cut , with recent claims of timing variations in wasp-3b @xcite and wasp-10b @xcite announced but unconfirmed , while a claimed detection of ttvs for ogle - tr-111b has not held up @xcite .
additionally , there have been claims of a tentative detection of variations in the transit duration of gj436b , increasing by roughly 3 minutes per year @xcite , consistent with the @xmath4 limit for a second planet in this system placed by transit timing @xcite .
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Suppose that you have an abstract for a scientific paper: new sufficient conditions , concerned with the coefficients of harmonic functions @xmath0 in the open unit disk @xmath1 normalized by @xmath2 , for @xmath3 to be harmonic close - to - convex functions are discussed .
furthermore , several illustrative examples and the image domains of harmonic close - to - convex functions satisfying the obtained conditions are enumerated .
this paper was published in the journal : + abstr .
appl .
anal .
vol.2012 , article i d 413965 , 12 pages .
+ http://www.hindawi.com/journals/aaa/2012/413965/ ' '' '' .
And you have already written the first three sentences of the full article: for a continuous complex - valued function @xmath4 @xmath5 , we say that @xmath3 is harmonic in the open unit disk @xmath6 if both @xmath7 and @xmath8 are real harmonic in @xmath1 , that is , @xmath7 and @xmath8 satisfy the laplace s equations @xmath9 a complex - valued harmonic function @xmath3 in @xmath1 is given by @xmath0 where @xmath10 and @xmath11 are analytic in @xmath1 .
we call @xmath10 and @xmath11 the analytic part and the co - analytic part of @xmath3 , respectively
. a necessary and sufficient condition for @xmath3 to be locally univalent and sense - preserving in @xmath1 is @xmath12 in @xmath1 ( see , @xcite or @xcite ) ..
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let @xmath13 denote the class of harmonic functions @xmath3 in @xmath1 with @xmath14 and @xmath15 .
thus , every normalized harmonic function @xmath3 can be written by @xmath16 where @xmath17 and @xmath18 , for convenience .
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12,760 |
Suppose that you have an abstract for a scientific paper: galaxies : active - cooling flows - evolution there is abundant evidence that heating processes in the central regions of elliptical galaxies have both prevented large - scale cooling flows and assisted in the expulsion of metal rich gas .
we now know that each such spheroidal system harbors in its core a massive black hole weighing approximately 0.13% of the mass in stars and also know that energy was emitted by each of these black holes with an efficiency exceeding 10% of its rest mass . since , if only 0.5% of that radiant energy were intercepted by the ambient gas , its thermal state would be drastically altered , it is worth examining in detail the interaction between the out - flowing radiation and the equilibrium or inflowing gas . on the basis of detailed hydrodynamic computations we find that relaxation oscillations are to be expected with the radiative feedback quite capable of regulating both the growth of the central black hole and also the density and thermal state of the gas in the galaxy .
mechanical input of energy by jets may assist or dominate over these radiative effects .
we propose specific observational tests to identify systems which have experienced strong bursts of radiative heating from their central black holes .
= 11 versim#1#22.9truept = 12 [ firstpage ] .
And you have already written the first three sentences of the full article: there are many properties of elliptical galaxies and spiral bulges ( systems which are , at a given luminosity , essentially identical ) that have been difficult to understand .
these are the observed regularities with regard to metallicity , gas content , etc . , which have largely been accepted as given .
now , we have discovered ( cf ..
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tremaine 2002 ) an important new fact , the apparently universal presence ( and mass ) of the central black holes ( ` bhs ' ) , that may provide the key to understanding these other properties .
the masses of the central bhs are known to be tightly correlated with the velocity dispersions of the spheroidal components ( e.g. , gebhardt 2000 , merritt & ferrarese 2001 , tremaine 2002 ) , or , alternatively , with the luminosity of those components ( cf .
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12,761 |
Suppose that you have an abstract for a scientific paper: we discuss the magnetic responses of vector meson masses based on the hidden local symmetry ( hls ) model in constant magnetic field , described by the lightest two - flavor system including the pion , rho and omega mesons in the spectrum .
the effective masses influenced under the magnetic field are evaluated in a way of the derivative / chiral expansion established in the hls model . at the leading order @xmath0 the g - factor of the charged rho meson
is fixed to be 2 , implying that the rho meson at this order is treated just like a point - like spin-1 particle . beyond the leading order ,
one finds anomalous magnetic interactions of the charged rho meson , involving the anomalous magnetic moment , which give corrections to the effective mass .
it is then suggested that up to @xmath1 the charged rho meson tends to become massless .
of interest is that nontrivial magnetic - dependence of neutral mesons emerges to give rise to the significant mixing among neutral mesons .
consequently , it leads to the dramatic enhancement of the omega meson mass , which is testable in future lattice simulations .
corrections from terms beyond @xmath1 are also addressed . .
And you have already written the first three sentences of the full article: exploring the quantum chromodynamics ( qcd ) in external magnetic field has recently attracted a lot of interest , such as the presumable presence of the strong magnetic field in the neutron star or magnetar , an early stage of heavy ion collisions , and some topics related to physics on the early universe .
for instance , in off - central heavy ion collisions , the scale of the magnetic field reaches up to about a few hundreds of mev , which could also be related to dynamics of quark - gluon plasma . in this respect ,
several fascinating qcd phenomena in the magnetic field have been proposed : the chiral magnetic effect , the magnetic catalysis or inverse magnetic catalysis , and so forth ..
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more on striking and exotic magnetic phenomena involves hadron physics : some of studies implies that vector meson ( rho meson ) can condense due to the presence of a strong magnetic field , which is naively expected from the landau - quantized mass of charged particles with spin 1 . in this respect ,
several works have been done based on effective models for qcd @xcite , and also some objection against the rho meson condensation from current lattice simulation has been reported , say , in ref .
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Suppose that you have an abstract for a scientific paper: we study the gravitational collapse of a homogeneous scalar field , minimally coupled to gravity , in the presence of a particular type of dynamical deformation between the canonical momenta of the scale factor and of the scalar field . in the absence of such a deformation
, a class of solutions can be found in the literature [ r. goswami and p. s. joshi , arxiv : gr - qc/0410144 ] , whereby a curvature singularity occurs at the collapse end state , which can be either hidden behind a horizon or be visible to external observers . however , when the phase - space is deformed , as implemented herein this paper , we find that the singularity may be either removed or instead , attained faster .
more precisely , for negative values of the deformation parameter , we identify the emergence of a negative pressure term , which slows down the collapse so that the singularity is replaced with a bounce . in this respect ,
the formation of a dynamical horizon can be avoided depending on the suitable choice of the boundary surface of the star .
whereas for positive values , the pressure that originates from the deformation effects assists the collapse toward the singularity formation . in this case , since the collapse speed is unbounded , the condition on the horizon formation is always satisfied and furthermore the dynamical horizon develops earlier than when the phase - space deformations are absent .
these results are obtained by means of a thoroughly numerical discussion . .
And you have already written the first three sentences of the full article: one of the most important contemporary challenges in gravitation theory and relativistic astrophysics is to fully describe the gravitational collapse of a massive body from initially regular matter distributions @xcite . while einstein s general theory of relativity
has been a highly successful theory in describing gravitation , it is a well - established result that a gravitational collapse process , governed by the einstein field equations with physically reasonable matter configurations , may induce a spacetime singularity to appear @xcite : physical parameters such as the matter energy density and spacetime curvatures will diverge . among the variety of models that have been investigated , the gravitational collapse of scalar fields have attracted particular attention : massless as well as massive scalar fields have been studied by applying analytical and numerical methods @xcite-@xcite . however ,
classical general relativity breaks down at the very late stages of a collapse scenario , where densities and curvatures are so extreme that quantum gravity effects may become more prominent , therefore possibly resolving the classical singularity @xcite ..
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one such possible effect is noncommutativity between spacetime coordinates , which was first proposed by snyder @xcite in an effort to introduce a short length cutoff ( the noncommutativity parameter ) in a lorentz covariant way .
the aim was to improve the renormalizability properties of relativistic quantum field theory ( see @xcite and references therein ) .
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12,763 |
Suppose that you have an abstract for a scientific paper: following a paper by athanasios angelakis and peter stevenhagen on the determination of imaginary quadratic fields having the same absolute abelian galois group @xmath0 , we study this property for arbitrary number fields .
we show that such a property is probably not easily generalizable , apart from imaginary quadratic fields , because of some @xmath1-adic obstructions coming from the global units . by restriction to the @xmath1-sylow subgroups of @xmath0 , we show that the corresponding study is related to a generalization of the classical notion of @xmath1-rational fields .
however , we obtain some non - trivial information about the structure of the profinite group @xmath0 , for every number field , by application of results published in our book on class field theory . a partir dun article de athanasios angelakis et peter stevenhagen sur
la dtermination de corps quadratiques imaginaires ayant le mme groupe de galois ablien absolu @xmath0 , nous tudions cette proprit pour les corps de nombres quelconques .
nous montrons quune telle proprit nest probablement pas facilement gnralisable , en dehors des corps quadratiques imaginaires , en raison dobstructions @xmath1-adiques provenant des units globales
. en se restreignant aux @xmath1-sous - groupes de sylow de @xmath0 , nous montrons que ltude correspondante est lie une gnralisation de la notion classique de corps @xmath1-rationnels .
cependant , nous obtenons des informations non triviales sur la structure du groupe profini @xmath0 , pour tout corps de nombres , par application de rsultats publis dans notre livre sur la thorie du corps de classes . .
And you have already written the first three sentences of the full article: let @xmath2 be a number field of signature @xmath3 for which @xmath4 $ ] , and let @xmath5 be the galois group @xmath6 where @xmath7 is the maximal abelian pro - extension of @xmath2 .
the question that was asked was the following : in what circumstances the groups @xmath8 and @xmath9 are isomorphic groups when @xmath10 and @xmath11 are two non - conjugate number fields ? a first paper on this subject was published in [ o ] by m. onabe . in [ as ] , a. angelakis and p. stevenhagen show that @xmath12 for a specific family of imaginary quadratic fields . in this paper ,
we prove ( under the leopoldt conjecture ) that , for any number field @xmath2 , the group @xmath5 _ contains _ a subgroup isomorphic to @xmath13 , where @xmath14 if @xmath15 is a non - trivial extension of @xmath16 distinct from @xmath17 , @xmath18 otherwise , and where @xmath19 is an integer whose local factors @xmath20 depend simply on the intersections @xmath21 ; then we give a class field theory interpretation of the quotient of @xmath5 by this subgroup , quotient which measures the defect of @xmath1-rationality for all @xmath1 ..
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such isomorphisms are only isomorphisms of abelian profinite groups for which galois theory and , a fortiori , arithmetical objects ( decomposition and inertia groups ) are not effective .
when an isomorphism is canonical ( for instance if it is induced by the reciprocity map of class field theory ) , we shall write @xmath22 contrary to the non - canonical case denoted @xmath23 if necessary . let @xmath1 be a fixed prime number and let @xmath24 be the @xmath1-hilbert class field ( in ordinary sense ) , the maximal @xmath1-ramified ( i.e. , unramified outside @xmath1 ) abelian pro-@xmath1-extension of @xmath2 ( in ordinary sense ) , the maximal tamely ramified abelian pro-@xmath1-extension of @xmath2 ( in restricted sense ) , the compositum of the @xmath25-extensions of @xmath2 , respectively .
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12,764 |
Suppose that you have an abstract for a scientific paper: toral introduced so - called cooperative parrondo games , in which there are @xmath0 players arranged in a circle . at each turn
one player is randomly chosen to play .
he plays either game @xmath1 or game @xmath2 , depending on the strategy .
game @xmath1 results in a win or loss of one unit based on the toss of a fair coin .
game @xmath2 results in a win or loss of one unit based on the toss of a biased coin , with the amount of the bias depending on whether none , one , or two of the player s two nearest neighbors have won their most recent games .
game @xmath1 is fair , so the games are said to exhibit the parrondo effect if game @xmath2 is losing or fair and the random mixture @xmath3 is winning . with @xmath4 ( resp . ,
@xmath5 ) denoting the mean profit per turn to the ensemble of @xmath6 players always playing game @xmath2 ( resp . , @xmath7 ) , we give sufficient conditions for @xmath8 to exist and show that @xmath9 nearly always exists , with the limits expressible in terms of a parameterized spin system on the one - dimensional integer lattice . for a particular choice of the parameters , we show that the parrondo effect ( i.e. , @xmath10 and @xmath11 ) is present in the @xmath6-player model if and only if @xmath6 is even . for the same choice of the parameters , we show that , with a suitable interpretation and for certain initial distributions , the parrondo effect is present in the spin system if and only if @xmath6 is even , @xmath6 being the number of consecutive players whose collective profit is tracked . _ ams 2000 subject classification _ : primary 60k35 ; secondary 60j20 . _
key words and phrases _ : parrondo s paradox , cooperative parrondo games , discrete - time markov chain , stationary distribution , strong law of large numbers , interacting particle system , spin system , ergodicity , duality . .
And you have already written the first three sentences of the full article: in toral s ( 2001 ) _ cooperative parrondo games _ , there are @xmath0 players labeled from 1 to @xmath6 and arranged in a circle in clockwise order . at each turn
, one player is chosen at random to play . call him player @xmath12 .
he plays either game @xmath1 or game @xmath2 , depending on the strategy . in game.
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@xmath1 he tosses a fair coin . in game
@xmath2 he tosses a @xmath13-coin ( i.e. , @xmath13 is the probability of heads ) if his neighbors @xmath14 and @xmath15 are both losers , a @xmath16-coin if @xmath14 is a loser and @xmath15 is a winner , a @xmath17-coin if @xmath14 is a winner and @xmath15 is a loser , and a @xmath18-coin if @xmath14 and @xmath15 are both winners .
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Suppose that you have an abstract for a scientific paper: we describe a new family of representations of @xmath0 in pu(2,1 ) , where @xmath1 is a hyperbolic riemann surface with at least one deleted point .
this family is obtained by a bending process associated to an ideal triangulation of @xmath1 .
we give an explicit description of this family by describing a coordinates system in the spirit of shear coordinates on the teichmller space .
we identify within this family new examples of discrete , faithful and type - preserving representations of @xmath0 . in turn
, we obtain a 1-parameter family of embeddings of the teichmller space of @xmath1 in the pu(2,1)-representation variety of @xmath0 .
these results generalise to arbitrary @xmath1 the results obtained in @xcite for the 1-punctured torus .
key words : complex hyperbolic geometry , representations of surface groups , teichmller space , deformation .
ams classification 51m10 , 32m15 , 22e40 .
And you have already written the first three sentences of the full article: let @xmath1 be an oriented surface with negative euler characteristic .
describing the representation variety of the fundamental group @xmath0 in a given lie group @xmath2 has been a major problem during the last two decades .
the central object in this field is the character variety @xmath3 this problem finds its source in the study of the teichmller space of @xmath1 , which classifies hyperbolic metrics or complex structures on @xmath1 ..
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riemann s uniformization theorem implies that the teichmller space of @xmath1 may be seen as the subset of rep@xmath4 consisting of conjugacy classes of discrete , faithful and type - preserving representations . in the case where @xmath1 is closed without boundary ,
goldman classified in @xcite the connected components of rep@xmath4 using the euler number of a representation .
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12,766 |
Suppose that you have an abstract for a scientific paper: we present exact results for the periodic anderson model for finite hubbard interaction @xmath0 on certain restricted domains of the model s phase diagram , in @xmath1 dimension . decomposing the hamiltonian into positive semidefinite terms we find two quantum states to be ground state , an insulating and a metallic one .
the ground state energy and several ground state expectation values are calculated . .
And you have already written the first three sentences of the full article: since the last decades compounds with lanthanide or actinide elements as heavy - fermion systems have attracted great interest because of their interesting experimental behavior .
numerous strange phases are thought to be possible as the ground state of such a system , ordered and disordered phases as well . as a theoretical background the periodic anderson model ( pam )
is one of the most important applicants to explain the physics in these systems ..
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however , despite its relatively simple structure up to now the complete exact solution of the model is not known even in one dimension and there are mostly approximative results . in 1993 , using a method proposed by brandt and giesekus @xcite , strack @xcite found the exact ground state in @xmath1 for the strong coupling @xmath2 case .
his results were generalized for @xmath3 dimensions by orlik and gulcsi @xcite also in @xmath2 .
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12,767 |
Suppose that you have an abstract for a scientific paper: a finite element method simulation of a carbon fibre reinforced polymer block is used to analyse the nonlinearities arising from a contacting delamination gap inside the material .
the ultrasonic signal is amplified and nonlinearities are analysed by delayed time reversal nonlinear elastic wave spectroscopy signal processing method .
this signal processing method allows to focus the wave energy onto the receiving transducer and to modify the focused wave shape , allowing to use several different methods , including pulse inversion , for detecting the nonlinear signature of the damage .
it is found that the small crack with contacting acoustic nonlinearity produces a noticeable nonlinear signature when using pulse inversion signal processing , and even higher signature with delayed time reversal , without requiring any baseline information from an undamaged medium . .
And you have already written the first three sentences of the full article: in the past , the use of carbon fibre reinforced polymer ( cfrp ) has been limited to non - structural parts of high - tech aeronautical products . in recent times , due to the effort of weight reduction and product lifetime enhancement , the application areas of cfrp have widened to the load - bearing parts of the aeronautical , automotive and civil engineering products . due to the increased demands on the strength of the cfrp products and possible complex failure mechanisms ,
the non - destructive testing ( ndt ) methods of cfrp have been an important applied and academic problem
. the complex failure mechanisms of cfrp include microcracking and delamination ..
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microcracking can occur at lower loads or due to aging and can be difficult to examine using ultrasonic ndt . with increased loading , the damage can evolve to delaminations , a very fine cracking between the layers of the cfrp .
these damages are difficult to detect using ultrasonic methods due to their small thicknesses . the damage can exhibit itself as a contact acoustical nonlinearity @xcite . a statistical distribution of microcracks or delamination damage in the material
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12,768 |
Suppose that you have an abstract for a scientific paper: the most recently available results from searches conducted by the four lep experiments at 189 gev center - of - mass energy for higgs bosons of the minimal supersymmetric standard model ( mssm ) are presented .
no evidence for a signal has been observed , and the null result is used by the experiments , both individually and collectively , to exclude regions of the mssm parameter space and to set lower limits on higgs boson masses at 95% confidence level in constrained mssm scenarios . .
And you have already written the first three sentences of the full article: the problem of the origin of electroweak symmetry breaking in fundamental theories of particle physics is often solved by invoking a higgs mechanism , where the symmetry is broken by the introduction of one or more scalar field doublets , which in turn give rise to the existence of physical neutral scalar particles called higgs bosons .
unfortunately the higgs masses are left as free parameters of the theory .
current fits to precision electroweak data , for example , can allow a standard model higgs boson ( @xmath0 ) mass of up to 262 gev/@xmath1 @xcite ..
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a common feature of supersymmetric extensions to the sm , however , is the prediction of the existence of a relatively light higgs boson . in particular , the minimal supersymmetric standard model ( mssm ) predicts the existence of five higgs bosons : two neutral and cp - even ( @xmath2 and @xmath3 , with @xmath4 by definition ) , one neutral and cp - odd ( @xmath5 ) , and two charged ( @xmath6 ) . at tree level , @xmath7 is predicted to be less than @xmath8 ; however , radiative corrections depending strongly on the top quark mass and mixing in the mssm s stop sector significantly alter this relation . the stop - mixing terms in turn depend on a number of unknown mssm parameters , but an upper bound on @xmath7 can still be set at around 130 gev/@xmath1 @xcite independent of the choice of these parameters .
a substantial fraction of this mass range can be explored at lep2 . in 1998 ,
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Suppose that you have an abstract for a scientific paper: we present cn and ch indices and caii triplet metallicities for 34 giant stars and chemical abundances for 33 elements in 14 giants in the globular cluster m2 . assuming the program stars are cluster members , our analysis reveals ( @xmath0 ) an extreme variation in cn and ch line strengths , ( @xmath1 ) a metallicity dispersion with a dominant peak at [ fe / h ] @xmath2 @xmath31.7 and smaller peaks at @xmath31.5 and @xmath31.0 , ( @xmath4 ) star - to - star abundance variations and correlations for the light elements o , na , al and si and ( @xmath5 ) a large ( and possibly bimodal ) distribution in the abundances of all elements produced mainly via the @xmath6-process in solar system material .
following @xcite , we define two groups of stars , `` @xmath7 '' and `` @xmath8-only '' , and subtract the average abundances of the latter from the former group to obtain a `` @xmath6-process residual '' .
this @xmath6-process residual is remarkably similar to that found in m22 and in m4 despite the range in metallicity covered by these three systems . with recent studies identifying a double subgiant branch in m2 and a dispersion in sr and ba abundances
, our spectroscopic analysis confirms that this globular cluster has experienced a complex formation history with similarities to m22 , ngc 1851 and @xmath9 centauri .
[ firstpage ] stars : abundances @xmath3 galaxy : abundances @xmath3 globular clusters : individual : ngc 7089 .
And you have already written the first three sentences of the full article: photometric studies have revealed complex structure in the colour - magnitude diagrams ( cmd ) of galactic globular clusters ( e.g. , see review by @xcite ) .
the subgiant branch region is of particular interest because differences in the luminosity of stars at this evolutionary stage require distinct ages and/or chemical compositions .
any globular cluster that exhibits a broadened or split subgiant branch must therefore have experienced a complex , and likely prolonged , chemical enrichment history when compared to globular clusters with a single subgiant branch population . @xmath9 centauri and m22 ( ngc 6656 ) are two galactic globular clusters with multiple subgiant branches ( e.g. , @xcite ;.
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@xcite ) . these two clusters are also notable for exhibiting a large star - to - star dispersion in the abundance of fe - peak and neutron - capture elements ( e.g. , @xcite ) .
ngc 1851 is another globular cluster with multiple subgiant branches @xcite .
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12,770 |
Suppose that you have an abstract for a scientific paper: the icecube neutrino observatory is a kilometer - scale detector currently under construction at the south pole .
the full detector will comprise 5,160 photomultipliers ( pmts ) deployed on 86 strings from 1.45 - 2.45 km deep within the ice .
as of the austral summer of 2009 - 10 , 73 out of the total number strings have been deployed , and the detector is reaching its final construction phase . a dense sub - array of 6 strings in the center of the detector ( deepcore ) has been already installed for enhancing the sensitivity to low energy neutrinos . the icecube detection principle is based on the measurement of the cherenkov light induced by ultra - relativistic muons and showers produced by neutrino interactions in the target matter of the detector .
the main scientific goal of the icecube experiment is the detection of astrophysical neutrinos that will help to understand and settle the unresolved questions about the origin and nature of cosmic rays . in this contribution we will present the latest results of the experiment concerning the search for neutrino point sources using the experimental data taken during 2008 - 09 where the detector was operated with a 40-string configuration .
the results of the analysis for steady individual neutrino sources as well as the stacking analysis from different catalogs will be presented . .
And you have already written the first three sentences of the full article: the icecube neutrino observatory is a neutrino telescope designed to detect high energy astrophysical neutrinos with energies @xmath0 gev .
such an observation could reveal the origins of cosmic rays ( cr ) and the possible connection to shock acceleration in supernova remnants ( snr ) , active galactic nuclei ( agn ) or gamma ray bursts ( grb ) .
an advantage of neutrino astronomy over other experimental observations such as gamma ray astronomy is the possibility to offer insight about the most energetic and dense parts of the universe since neutrinos are weakly interactive particles that can travel through matter without interacting ..
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nonetheless , this advantage also makes the neutrino detection a technological challenge since a large amount of volume is required to observe neutrino interactions .
the icecube neutrino observatory uses the antarctic ice as a detection volume where a neutrino interaction will produce a muon ( or other charged lepton ) as a result of the charged current interaction .
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Suppose that you have an abstract for a scientific paper: new expansions for some functions related to the zeta function in terms of the pochhammer s polynomials are given ( coefficients @xmath0 , @xmath1 , @xmath2 and @xmath3 ) .
in some formal limit our expansion @xmath0 obtained via the alternating series gives the regularized expansion of maslanka for the zeta function .
the real and the imaginary part of the function on the critical line is obtained with a good accuracy up to @xmath4 .
then , we give the expansion ( coefficient @xmath5 ) for the derivative of @xmath6 . the critical function of the derivative , whose bounded values for @xmath7 at large values of _ k _ should ensure the truth of the riemann hypothesis ( rh ) , is obtained either by means of the primes or by means of the zeros ( trivial and non - trivial ) of the zeta function . in a numerical experiment performed up to high values of _
k _ i.e. up to @xmath8 we obtain a very good agreement between the two functions , with the emergence of twelve oscillations with stable amplitude . for a special case of values of the two parameters entering in the general pochhammer s expansion
it is argued that the bound on the critical function should be given by the euler constant gamma .
[ i1 ] .
And you have already written the first three sentences of the full article: lately there has been new interest in the study of the expansion of the zeta function via the pochhammer s polynomials .
this is related to the original idea of riesz @xcite and of hardy - littlewood @xcite at the beginning of the last century . in a pioneering work
@xcite maslanka obtained a regularized expansion for the zeta function ( with coefficients @xmath9 ) and baez - duarte for the expansion of the reciprocal of the zeta function ( with coefficients @xmath10 ) for the riesz case @xcite ..
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other cases of interest have also recently been studied @xcite . as pointed out in @xcite , the discrete version by means of the pochhammer s polynomials @xmath11 , where @xmath12 is the complex variable and _ k _ is an integer , has advantages especially in the context of numerical experiments in connection with some `` kind of verification '' in the direction to believe that the rh may be true . in this work
we first derive a new expansion for the zeta function in terms of the pochhammer s polynomials via the alternating series ( with new coefficients @xmath0 ) . in some formal limit
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12,772 |
Suppose that you have an abstract for a scientific paper: we use a recently proposed holographic kondo model as a well - understood example of ads / boundary cft ( bcft ) duality , and show explicitly that in this model the bulk volume decreases along the rg flow .
we then obtain a proof that this volume loss is indeed a generic feature of ads / bcft models of the type proposed by takayanagi in 2011 .
according to recent proposals holographically relating bulk volume to such quantities as complexity or fidelity susceptibility in the dual field theory , this suggests the existence of a complexity or fidelity susceptibility analogue of the affleck - ludwig @xmath0-theorem , which famously states the decrease of boundary entropy along the rg flow of a bcft .
we comment on this possibility . + mario flory , + _ institute of physics , jagiellonian university , + ojasiewicza 11 , 30 - 348 krakw , poland _ .
And you have already written the first three sentences of the full article: the ads / cft correspondence @xcite suggests that certain conformal field theories ( cfts ) can be holographically dual to gravity theories with asymptotically ads spacetimes .
the ads / cft correspondence can hence be used as a tool to gain understanding of various field theory phenomena , usually at strong coupling , by phrasing the problem at hand in terms of the dual gravitational theory . amongst many other things , topics to which ads / cft methods have been applied in the past were rg flows ( see e.g. @xcite ) , holographic superconductors @xcite and _ boundary cfts ( bcfts ) _ , see @xcite for a cursory overview over different types of ads / bcft models proposed in the literature . in descriptions of the ads / cft correspondence
, one will often encounter the term _ holographic dictionary _ , describing the idea of a , real or imagined , list of quantities defined either on the bulk ( ads ) or field theory ( cft ) side that are mapped to each other via the correspondence ..
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an example of a well - known entry into this dictionary is the holographic _ entanglement entropy _
formula @xcite @xmath1 where the entanglement entropy @xmath2 of a certain subregion is a cft quantity , while @xmath3 is the ( bulk ) newton constant and @xmath4 is the area of an extremal co - dimension two surface in the bulk ( ads ) spacetime .
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12,773 |
Suppose that you have an abstract for a scientific paper: the effects of a radiation field ( rf ) on the unstable modes developed in relativistic electron beam plasma interaction are investigated assuming that @xmath0 , where @xmath1 is the frequency of the rf and @xmath2 is the plasma frequency .
these unstable modes are parametrically coupled to each other due to the rf and are a mix between two stream and parametric instabilities .
the dispersion equations are derived by the linearization of the kinetic equations for a beam plasma system as well as the maxwell equations . in order to highlight the effect of the radiation field we present a comparison of our analytical and numerical results obtained for nonzero rf with those for vanishing rf .
assuming that the drift velocity @xmath3 of the beam is parallel to the wave vector @xmath4 of the excitations two particular transversal and parallel configurations of the polarization vector @xmath5 of the rf with respect to @xmath4 are considered in detail .
it is shown that in both geometries resonant and nonresonant couplings between different modes are possible .
the largest growth rates are expected at the transversal configuration when @xmath5 is perpendicular to @xmath4 . in this case
it is demonstrated that in general the spectrum of the unstable modes in @xmath6@xmath7 plane is split into two distinct domains with long and short wavelengths , where the unstable modes are mainly sensitive to the beam or the rf parameters , respectively . in parallel configuration , @xmath8 , and at short wavelengths the growth rates of the unstable modes are sensitive to both beam and rf parameters remaining insensitive to the rf at long wavelengths . .
And you have already written the first three sentences of the full article: the interaction of a relativistic electron beam ( reb ) with a plasma is a subject of relevance for many fields of physics ranging from inertial fusion to astrophysics @xcite .
this interaction is also relevant , among others , for fast ignition scenario ( fis ) @xcite where the precompressed deuterium tritium ( dt ) core of a fusion target is to be ignited by a laser generated relativistic electron beam .
the reb quickly prompts a return current so that one eventually has to deal with a typical two stream configuration which is subjected to various electromagnetic instabilities ..
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much effort have been devoted in the last years to investigate these instabilities @xcite , whether it be the two
stream @xcite , the filamentation @xcite or weibel @xcite instabilities .
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12,774 |
Suppose that you have an abstract for a scientific paper: by comparing the observed orbital decay of the binary pulsars psr b1913 + 16 and psr b1534 + 12 to that predicted by general relativity due to gravitational - wave emission , we are able to bound the mass of the graviton to be less than @xmath0 at @xmath1 confidence .
this is the first such bound to be derived from dynamic gravitational fields .
it is approximately two orders of magnitude weaker than the static - field bound from solar system observations , and will improve with further observations . .
And you have already written the first three sentences of the full article: general relativity assumes that the graviton has zero rest mass . for static gravitational fields a nonzero graviton mass @xmath2 would cause the potential to tend to the yukawa form @xmath3 , effectively cutting off gravitational interactions at distances larger than the compton wavelength @xmath4 of the graviton .
current experimental limits on the graviton mass are based on the apparent absence of such a cutoff in the solar system @xcite and in galaxy and cluster dynamics @xcite .
the study of dynamic gravitational fields allows new and independent limits to be placed on the graviton mass ..
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for example , will @xcite and larson and hiscock @xcite have shown how future observations of gravitational waves may be used to bound the graviton mass via comparison to the dispersion formula @xmath5 here we propose a new technique for limiting @xmath2 using available data on the orbital decay of binary pulsars . consider the hulse - taylor binary pulsar , psr b1913 + 16 , for which the observed orbital decay attributed to gravitational - wave emission agrees with the predictions of general relativity to approximately @xmath6 .
a nonzero graviton mass would alter the energy emission rate , @xmath7 , where @xmath8 for these binary systems . ] and destroy this agreement ; for gravitational waves at twice the orbital frequency of psr b1913 + 16 , requiring @xmath9 implies @xmath10 .
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12,775 |
Suppose that you have an abstract for a scientific paper: we present time - resolved optical spectroscopy of the counterpart to the high - inclination black hole low - mass x - ray binary swift j1357.2 - 0933 in quiescence .
absorption features from the mass donor star were not detected . instead the spectra display prominent broad double - peaked h@xmath0 emission and weaker hei emission lines . from the h@xmath0 peak - to - peak separation
we constrain the radial velocity semi - amplitude of the donor star to @xmath1 km s@xmath2 .
further analysis through radial velocity and equivalent width measurements indicates that the h@xmath0 line is free of variability due to s - wave components or disc eclipses . from our data and previous observations during outburst ,
we conclude that long - term radial velocity changes ascribed to a precessing disc were of low amplitude or not present .
this implies that the centroid position of the line should closely represent the systemic radial velocity , @xmath3 . using the derived @xmath4 km s@xmath2 and the best available limits on the source distance
, we infer that the black hole is moving towards the plane in its current galactic orbit unless the proper motion is substantial .
finally , the depth of the central absorption in the double peaked profiles adds support for swift j1357.2 - 0933 as a high - inclination system . on the other hand
, we argue that the low hydrogen column density inferred from x - ray fitting suggests that the system is not seen edge - on .
binaries : close ; accretion , accretion discs ; x rays : binaries ; black hole physics ; stars : individual : swift j1357.2 - 0933 .
And you have already written the first three sentences of the full article: the x - ray transient swift j1357.2 - 0933 ( hereafter j1357.2 ) was discovered in outburst on 28 jan 2011 with the burst alert telescope on - board _ swift _ ( krimm et al .
follow - up observations with the _ swift _ x - ray telescope revealed a spectrum consistent with an absorbed power law with a low hydrogen column density @xmath5 of @xmath6 @xmath7 and a photon index that evolved from @xmath8 to 2.1 during the outburst decline ( krimm et al . 2011b , armas padilla et al . 2013 ) .
a 0.5 - 10 kev outburst peak luminosity of @xmath9 erg s@xmath2 is inferred from these observations ..
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in addition , xmm - newton data obtained on 5 feb 2011 could be fitted with a three component model : the above mentioned power law with a 93 percent contribution to the total flux , a thermal ( disc ) component with @xmath10 kev , and one edge at 0.73 kev .
the thermal component is interpreted as soft emission originating in the accretion disc , while the edge is associated to interstellar iron .
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12,776 |
Suppose that you have an abstract for a scientific paper: additive manufacturing of polymer bonded magnets is a recently developed technique , for single - unit production , and for structures that have been impossible to manufacture previously .
also new possibilities to create a specific stray field around the magnet are triggered .
the current work presents a method to 3d print polymer bonded magnets with a variable magnetic compound density distribution .
a low - cost , end - user 3d printer with a mixing extruder is used to mix permanent magnetic filaments with pure pa12 filaments .
the magnetic filaments are compounded , extruded , and characterized for the printing process . to deduce the quality of the manufactured magnets with a variable compound density ,
an inverse stray field framework is used .
the effectiveness of the printing process and the simulation method is shown .
it can also be used to manufacture magnets that produce a predefined stray field in a given region .
examples for sensor applications are presented .
this setup and simulation framework allows the design and manufacturing of polymer bonded permanent magnets which are impossible to create with conventional methods . .
And you have already written the first three sentences of the full article: additive manufacturing is an affordable , rapid technique to manufacture models , tools , prototypes , or end products .
the production is carried out directly from formless ( liquids , powders , etc . ) or form - neutral ( tape , wire ) material mostly by means of thermal or chemical processes .
no specific tools are required for a specific object with a possibly complex shape ..
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a well established additive manufacturing method is the fused deposition modeling ( fdm ) technology .
fdm , also referred to as 3d printing , is a process that uses wire - shaped thermoplastic filaments .
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12,777 |
Suppose that you have an abstract for a scientific paper: most gravitational lens galaxies are early - type galaxies in relatively low density environments .
we show that they lie on the same fundamental plane as early - type galaxies in both local and distant rich clusters .
their surface brightness evolution requires a typical star formation epoch of @xmath0-@xmath1 , almost indistinguishable from that of rich cluster galaxies at comparable redshifts .
the restricted galaxy type range of the lenses means that photometric redshifts work well even with only 13 filter photometry .
we make preliminary measurements of the mass and luminosity functions of the lens galaxies , and find they are consistent with the standard model used for deriving cosmological limits using lens statistics . as expected for a mass - weighted sample , they are more massive and more luminous than the overall early - type galaxy population . psfig .
And you have already written the first three sentences of the full article: gravitational lens galaxies are a unique sample , because they are the only galaxies selected based on mass rather than luminosity . as such , the average properties of the lens galaxies are _ identical _ to the mass - weighted average properties of _ all _ galaxies at a given redshift . at intermediate redshifts ( @xmath2 )
, they are also the largest sample of galaxies with known masses outside the cores of rich clusters .
historically , the interpretation of the mass measurements has been hampered by a lack of accurate measurements of the _ light_. eliminating this rather peculiar problem for an astronomical sample is a primary goal of the castles ( cfa / arizona space telescope lens survey ) project ( see falco et al . in these proceedings ) ..
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if we combine accurate measurements of the mass and the light with the wide range of lens redshifts , then we have an excellent tool for studying the evolution of galaxy mass - to - light ( m / l ) ratios with redshift .
our method is similar to that introduced by van dokkum & franx ( 1996 ) and used by kelson et al .
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12,778 |
Suppose that you have an abstract for a scientific paper: we present some preliminary results from an on - going study of the evolution of stellar populations in rich clusters of galaxies .
our baseline sample contains core line - strength measurements from 183 galaxies with @xmath0 from four clusters with @xmath1 , against which observations of higher - redshift clusters can be compared . using predictions from stellar population models to compare with our measured line strengths we can derive _ relative _ luminosity - weighted mean ages and metallicities for the stellar populations in each of our clusters .
it must be stressed that these ages and metallicities are only accurate when used in an relative sense as the stellar population models , due to differing abundance ratios used in the models compared to those observed in elliptical galaxies , provide inaccurate absolute ages and metallicities .
we also investigate the mg__b__@xmath2-@xmath3 and h@xmath4-@xmath3 scaling relations .
we find that mg__b__@xmath2 is correlated with @xmath3 , the likely explanation being that larger galaxies are better at retaining their heavier elements due to their larger potentials .
h@xmath4 , on the other hand , we find to be anti - correlated with @xmath3 .
this result implies that the stellar populations in larger galaxies are older than in smaller galaxies . .
And you have already written the first three sentences of the full article: the formation and evolution of clusters of galaxies and of their early - type galaxy population is a topic of active debate .
studying the integrated light from stellar populations can help to discriminate between models of giant elliptical galaxy formation : the monolithic collapse model ( ( * ? ? ?
* eggen et al . , 1962 ) ) in which giant elliptical galaxies form rapidly in a process that can essentially be considered a single collapse and the hierarchical merging model ( @xcite ) in which giant elliptical galaxies are built up over a long timescale by distinct merger events . if it was found that early - types were largely coeval in clusters then this would favour the monolithic collapse model , whereas a large spread in ages would favour hierarchical merging . increasing a galaxy s age by a factor of two while decreasing it s metallicity by a factor of three results in a spectrum almost indistinguishable from the original ( @xcite ) ..
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this age / metallicity degeneracy can be partially broken by comparing age - sensitive spectroscopic indices with metallicity - sensitive spectroscopic indices . by plotting two such indices against each other and comparing the results to stellar population models ( e.g. @xcite ; @xcite )
we can determine the mean relative luminosity - weighted age and metallicity of a given stellar population .
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12,779 |
Suppose that you have an abstract for a scientific paper: a model is presented for generation of fast solar wind in coronal holes , relying on heating that is dominated by turbulent dissipation of mhd fluctuations transported upwards in the solar atmosphere .
scale - separated transport equations include large - scale fields , transverse alfvnic fluctuations , and a small compressive dissipation due to parallel shears near the transition region .
the model accounts for proton temperature , density , wind speed , and fluctuation amplitude as observed in remote sensing and _ in situ
_ satellite data . .
And you have already written the first three sentences of the full article: an open question in solar and heliospheric physics is to identify the physical processes responsible for heating the corona and accelerating the fast solar wind streams emanating from coronal holes .
this requires that a fraction of the energy available in photospheric motions be transported through the chromospheric transition region , and dissipated in the corona .
the measured speeds of fast solar wind streams require spatially extended heating @xcite ..
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the physical mechanisms for this transport and dissipation have remained elusive .
some models have resorted to use of a parametrically defined heat deposition ( a `` heat function '' ) that decays exponentially with height , or anomalous heat conduction that redistributes energy along field - lines @xcite .
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Suppose that you have an abstract for a scientific paper: we investigate parity - violating asymmetries in @xmath0 radiative capture at thermal neutron energies and in deuteron electro - disintegration in quasi - elastic kinematics , using the ddh model for the parity - violating nucleon - nucleon interaction .
we find dramatic cancellations between the asymmetries induced by the parity - violating interaction and those arising from the associated parity - violating pion - exchange currents . in the @xmath0 capture ,
the model - dependence of the result is nevertheless quite small , because of constraints arising through the siegert evaluation of the relevant @xmath1 matrix elements . in
quasi - elastic electron scattering these processes are found to be insignificant compared to the asymmetry produced by @xmath2-@xmath3 interference on individual nucleons .
these two experiments , then , provide clean probes of different aspects of weak - interaction physics associated with parity violation in the @xmath4 system . .
And you have already written the first three sentences of the full article: two - nucleon experiments are the clearest probes of hadronic parity violation .
a recent experiment has measured the longitudinal asymmetry in @xmath5 elastic scattering @xcite , while another one is underway to measure the photon asymmetry in low - energy @xmath0 radiative capture @xcite .
this experiment has been designed to provide a definitive measurement of the weak @xmath6@xmath7@xmath7 coupling constant , which determines the longest - range part of the parity - violating nucleon - nucleon interaction ..
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we investigate this process using the desplanques , donoghue , and holstein ( ddh ) meson - exchange model of the parity - violating @xmath7@xmath7 interaction @xcite .
we separately evaluate the contributions from the hadronic weak interaction and the associated two - body currents .
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Suppose that you have an abstract for a scientific paper: we introduce the epidemic quasimetric on graphs and study its behavior with respect to clustering techniques . in particular we compare its behavior to known objects such as the graph distance , effective resistance , and modulus of curve families . .
And you have already written the first three sentences of the full article: this study was initiated by the need to analyze real world data collected in the rural town of chanute , kansas .
the goal was to study and simulate potential epidemic outbreaks . from the survey ,
a contact network was constructed representing the sampled population and their potential relationships ..
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mathematically , this is just a graph where the vertices represent people and the edges represent possible interactions . in this paper
, we introduce a new geometric quantity , the epidemic quasimetric , which we study and relate to more classical quantities , such as effective resistance .
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Suppose that you have an abstract for a scientific paper: in this talk , we propose a model of mirage mediation , in which peccei - quinn symmetry is incorporated . in this _ axionic mirage mediation _ , it is shown that the peccei - quinn symmetry breaking scale is dynamically determined around @xmath0 gev to @xmath1 gev due to the supersymmetry breaking effects .
the problems in the original mirage mediation such as the @xmath2-problem and the moduli problem can be solved simultaneouly .
furthermore , in our model the axino , which is the superpartner of the axion , is the lightest sparticle .
address = department of physics , tohoku university , sendai , 980 - 8578 , japan .
And you have already written the first three sentences of the full article: supersymmetry ( susy ) deeply fascinates us as a solution to the hierarchy problem .
it has , however , to be broken because superparticles have not been discovered yet .
the phenomenological aspects such as mass spectrum , collider signature and so forth , depend on how susy is broken ..
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therefore , to understand the susy breaking mechanism is important . in superstring theory ,
one of the most plausible mediation mechanisms is the moduli mediation . on the other hand ,
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12,783 |
Suppose that you have an abstract for a scientific paper: the problem of fundamental units is discussed in the context of achievements of both theoretical physics and modern metrology . on one hand , due to fascinating accuracy of atomic clocks , the traditional macroscopic standards of metrology ( second , metre , kilogram )
are giving way to standards based on fundamental units of nature : velocity of light @xmath0 and quantum of action @xmath1 .
on the other hand , the poor precision of gravitational constant @xmath2 , which is widely believed to define the `` cube of theories '' and the units of the future `` theory of everything '' , does not allow to use @xmath2 as a fundamental dimensional constant in metrology .
the electromagnetic units in si are actually based on concepts of prerelativistic classical electrodynamics such as ether , electric permitivity and magnetic permeability of vacuum .
concluding remarks are devoted to terminological confusion which accompanies the progress in basic physics and metrology . [ 04 ] .
And you have already written the first three sentences of the full article: the problem of fundamental units has many facets , three of which seem to be most important : theoretical , experimental and technological . at present
they are inseparable .
theory , the so called standard model , formulates basic physical laws and mathematical methods of their application ..
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theoretical laws were established and continue to be established and tested on the basis of ingenious experiments and astronomical observations of higher and higher accuracy for an expanding space of parameters .
precision experiments and observations , in their turn , are unthinkable without modern high technologies , including lasers and computers .
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12,784 |
Suppose that you have an abstract for a scientific paper: we present a numerical code designed to study astrophysical phenomena involving dynamical spacetimes containing black holes in the presence of relativistic hydrodynamic matter .
we present evolutions of the collapse of a fluid star from the onset of collapse to the settling of the resulting black hole to a final stationary state . in order to evolve stably after the black hole forms , we excise a region inside the hole before a singularity
is encountered .
this excision region is introduced after the appearance of an apparent horizon , but while a significant amount of matter remains outside the hole .
we test our code by evolving accurately a vacuum schwarzschild black hole , a relativistic bondi accretion flow onto a black hole , oppenheimer - snyder dust collapse , and the collapse of nonrotating and rotating stars .
these systems are tracked reliably for hundreds of @xmath0 following excision , where @xmath0 is the mass of the black hole .
we perform these tests both in axisymmetry and in full 3 + 1 dimensions .
we then apply our code to study the effect of the stellar spin parameter @xmath1 on the final outcome of gravitational collapse of rapidly rotating @xmath2 polytropes .
we find that a black hole forms only if @xmath3 , in agreement with previous simulations .
when @xmath4 , the collapsing star forms a torus which fragments into nonaxisymmetric clumps , capable of generating appreciable `` splash '' gravitational radiation . .
And you have already written the first three sentences of the full article: since many of the most interesting phenomena in astrophysics involve black holes , the modeling of black hole spacetimes is one the most important problems in numerical general relativity .
it is also one of the most challenging problems .
black hole evolutions present all the usual difficulties of numerical relativity , such as the need to find a stable form of the field evolution equations and the need to find a practical coordinate system ..
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in addition , handling the singular region is very subtle for a numerical code ; the black hole singularity must be avoided to allow the exterior evolution to continue far into the future .
one of the most promising methods to date of dealing with black hole singularities is black hole excision .
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12,785 |
Suppose that you have an abstract for a scientific paper: the evidently supersymmetric four - dimensional wess - zumino model with quenched disorder is considered at the one - loop level .
the infrared fixed points of a beta - function form the moduli space @xmath0 where two types of phases were found : with and without replica symmetry . while the former phase possesses only a trivial fixed point ,
this point become unstable in the latter phase which may be interpreted as a spin glass phase .
-10 mm 0 landau-97-tmp-1 + itep - th-5/97 + hep - th/9702063 + + sergei gukov + + + 0 * _ the devil is not so black as he is painted . _ * .
And you have already written the first three sentences of the full article: there is a great deal of field theory models describing a system in quenched random fields or coupling constants ( @xcite , @xcite , @xcite , _
etc_. ) . in solid state physics
such models naturally arise the corresponding pure systems whenever impurities are introduced ..
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it is interesting to extend randomness to other well - studied field theories , just as , for example in @xcite , disorder was implemented into minimal conformal models . as shown in @xcite and subsequent papers stochastic equations as well as the field theories in presence of random external sources often prove to possess some hidden supersymmetry .
kurchan @xcite indorsed this result for spin glass dynamics .
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12,786 |
Suppose that you have an abstract for a scientific paper: the limit gaussian distribution of multivariate weighted functionals of nonlinear transformations of gaussian stationary processes , having multiple singular spectra , is derived , under very general conditions on the weight function .
this paper is motivated by its potential applications in nonlinear regression , and asymptotic inference on nonlinear functionals of gaussian stationary processes with singular spectra . , , .
And you have already written the first three sentences of the full article: during the last thirty years , a number of papers have been devoted to limit theorems for nonlinear transformations of gaussian processes and random fields .
the pioneering results are those of taqqu @xcite and dobrushin and major @xcite , for convergence to gaussian and non - gaussian distributions , under long - range dependence , in terms of hermite expansions , as well as breuer and major @xcite , ivanov and leonenko @xcite , chambers and slud @xcite , on convergence to the gaussian distribution by using diagram formulas or graphical methods .
this line of research continues to be of interest today ; see berman @xcite for @xmath0-dependent approximation approach , ho and hsing @xcite for martingale approach , nualart and peccati @xcite ( see also peccati and tudor @xcite ) for the application of malliavin calculus , nourdin and peccati @xcite in relation to stein s method and exact berry esseen asymptotics for functionals of gaussian fields , avram , leonenko and sakhno @xcite for an extension of graphical method for random fields , to name only a few papers ..
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the volume of doukhan , oppenheim and taqqu @xcite contains outstanding surveys of the field .
limit theorems for weighted functionals of stochastic processes , and for processes with seasonalities were considered by a number of authors , including rosenblatt @xcite , oppenheim , ould haye and viano r37 , haye @xcite , and their references .
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12,787 |
Suppose that you have an abstract for a scientific paper: i present a review of x - ray observations of supernova remnants with an emphasis on shell - type remnants .
the topics discussed are the observation of fresh nucleosynthesis products , shock heating and cosmic ray acceleration . .
And you have already written the first three sentences of the full article: although radio and optical observations have played an important role in identifying and characterizing supernova remnants ( snrs ) , most of the shock heated material is primarily visible in x - rays , having temperatures of typically @xmath0 k. the emission mechanisms are bremsstrahlung and line radiation , but a number of remnants are now known to emit x - ray synchrotron radiation from ultra - relativistic electrons , as well .
this was already known for pulsar wind nebula dominated , or crab - like remnants , which fall outside the scope of this review , but also shell - type remnants like sn 1006 emit synchrotron radiation from electrons accelerated by the blast wave @xcite .
the x - ray line emission of snrs is in particular interesting , as it allows the study of the most abundant metals , the so called @xmath1-elements , which prominently feature in the x - ray spectra of young snrs like cas a , tycho ( sn 1576 ) and kepler ( sn 1064 ) . this line emission , and mass estimates based on the x - ray emission ,.
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give important information on the nucleosynthesis yields of the explosions , which can then be compared to theoretical supernova ( sn ) models @xcite .
the line and bremsstrahlung emission give us a window on the past of the snr : its progenitor and the sn explosion .
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12,788 |
Suppose that you have an abstract for a scientific paper: by means of space - group symmetry arguments , we argue that the electronic pairing in iron - based high temperature superconductors shows a structure which is a linear combination of _ planar _ s - wave and d - wave symmetry channels , both preserving the 3-dimensional @xmath0 irreducible representation of the corresponding crystal point - group .
we demonstrate that the s- and d - wave channels are determined by the parity under reflection of the electronic orbitals through the iron planes , and by improper rotations around the iron sites . we provide evidence of these general properties by performing accurate quantum monte carlo ab - initio calculations of the pairing function , for a fese lattice with tetragonal experimental geometry at ambient pressure .
we find that this picture survives even in the fese under pressure and at low temperatures , when the tetragonal point - group symmetry is slightly broken . in order to achieve a higher resolution in momentum space
we introduce a bcs model that faithfully describes our qmc variational pairing function on the simulated 4x4 fese unit cell .
this allows us to provide a k - resolved image of the pairing function , and show that non - isotropic contributions in the bcs gap function are related to the improper s - wave symmetry . our theory can rationalize and explain a series of contradictory experimental findings , such as the observation of twofold symmetry in the fese superconducting phase , the anomalous drop of @xmath1 with co - impurity in lafeaso@xmath2f@xmath3 , the @xmath4-to-@xmath5-wave gap transition in bafe@xmath6as@xmath6 under k doping , and the nodes appearing in the lifeas superconducting gap upon p isovalent substitution .
And you have already written the first three sentences of the full article: the pairing symmetry of the superconducting state in iron - based superconductors ( ibs ) has been one of the most debated subjects since their first discovery , in both theory and experiments.@xcite its determination is particularly challenging in the ibs for their complex electronic structure , with a strong multiband character , and a fermi surface constituted by many sheets , which can vary with doping and chemical composition . moreover , the ibs families are usually compensated metals , and thus both electrons and holes are involved in the paired state .
weak - coupling rpa approaches , coupled to multiband bcs theory , yield a pairing function with global s - wave ( @xmath0 ) symmetry , but with electron and holes pockets having opposite sign .
this scenario , dubbed @xmath7 , was first proposed by mazin _ _ et al.__@xcite complemented later with its variants , called `` extended @xmath7'',@xcite in the case that accidental nodes appear on a single fermi sheet without breaking the full rotational symmetry ..
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the latest generalizations include also `` weak '' nodal lines which develop as closed loops on the 3-dimensional ( 3d ) fermi surface.@xcite a variety of experiments has been performed to probe the pairing symmetry of ibs , ranging from thermal conductivity and specific heat measurements to angle - resolved photoemission spectroscopy . while there is no doubt on the spin singlet nature of the pairing state as revealed by the knight shift,@xcite the presence of nodes and the total symmetry of the spatial part of the pairing function are controversial .
in fact , the experimental outcome seems to lack universality , as it depends crucially on the `` family '' of tested compound , its doping , its isovalent substitutions , and its level of disorder .
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12,789 |
Suppose that you have an abstract for a scientific paper: in this work we introduce a low - energy hamiltonian for single layer and bilayer black phosphorus that describes the electronic states at the vicinity of the gamma point .
the model is based on a recently proposed tight - binding description for electron and hole bands close to the fermi level .
we calculate expressions for the landau level spectrum as function of magnetic field and in the case of bilayer black phosphorus we investigate the effect of an external bias on the electronic band gap .
the results showcase the highly anisotropic character of black phosphorus and in particular for bilayer bp , the presence of bias allows for a field - induced semiconductor - metal transition . in the last ten years the properties of crystals consisting of one or few atomic layers
has been the focus of intense research .
such interest arose mainly due to the production of graphene in 2004 , which has been shown to display remarkable electronic , optical and mechanical properties @xcite . since then , there has been a growing interest in the production of other low - dimensional crystals .
the investigation of analogs of graphene has resulted in the discovery of several single layer crystals of different elements , such as silicon ( silicene ) @xcite , germanium ( germanene ) @xcite , as well as a class of materials known as transition metal dichalcogenides @xcite . some of these materials may soon find use in electronic devices , mainly due to the fact that in contrast with graphene , they present a band gap in their electronic spectrum , albeit with a lower carrier mobility . among the most promising of these 2d materials
is an allotrope of phosphorus , known as black phosphorus ( bp ) @xcite , which is that element s most stable crystal at room temperature and pressure . in bulk
, bp is a narrow gap semiconductor with a orthorhombic structure that consists of atoms covalently bound into layers coupled by van der waals interactions .
similarly to graphene , bp can be mechanically exfoliated to....
And you have already written the first three sentences of the full article: the structure of each layer of bp has phosphorus atoms covalently coupled to three nearest neighbors .
the resulting lattice resembles the honeycomb structure of graphene , however in phosphorene the sp@xmath6 hybridization of the @xmath7s and @xmath7p atomic orbitals creates ridges that result in a puckered surface ( fig .
1 ) . using the tight - binding model proposed in ref @xcite , we can write the hamiltonian for single layer black phosphorus as @xmath8 with eigenvectors given by @xmath9^t$ ] and where @xmath10 represent the on - site energies - which we henceforth assume as equal to @xmath11 , with the @xmath12 subscripts denoting the four sublattice labels shown in fig.
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the interaction terms are given in the appendix . by taking into account the symmetries of the phosphorene lattice
, one can write a reduced two - band hamiltonian for single layer black phosphorus at the vicinity of the fermi level as @xmath13 which acts on the spinors @xmath14 from the hamiltonian eq.(2 ) one can obtain the energies for the bottom of the conduction band and the top of the valence band as @xmath15 and @xmath16 that leads to a gap of @xmath17 ev .
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12,790 |
Suppose that you have an abstract for a scientific paper: we present results of two - colour photometry with high time resolution of the violently variable bl lac object ao 0235 + 164 .
we have found extreme intranight variability with amplitudes of @xmath0 % over time scales of 24 hours .
changes of 0.5 magnitudes in both @xmath1 and @xmath2 bands were measured within a single night , and variations up to 1.2 magnitudes occurred from night to night . a complete outburst with an amplitude @xmath3 % was observed during one of the nights , while the spectrum remained unchanged .
this seems to support an origin based on a thin relativistic shock propagating in such a way that it changes the viewing angle , as recently suggested by kraus et al .
( 1999 ) and qian et al .
( 2000 ) . .
And you have already written the first three sentences of the full article: the bl lac object ao 0235 + 164 is one of the most intensively studied blazars .
it is a very compact source ( e.g. jones et al .
1984 , chu et al . 1996 ) which ejects superluminal components with apparent velocities up to @xmath4 ( see fan et al . 1996 and references therein ) ..
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the object presents emission lines at a redshift of @xmath5 and foreground absorption features at @xmath6 and @xmath7 , which have led several authors to study a gravitational microlensing scenario for this source ( e.g. stickel et al .
1988 , abraham et al .
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12,791 |
Suppose that you have an abstract for a scientific paper: we have applied an eccentric accretion disc theory in simplified form to the case of an accretion disc in a binary system , where the disc contains the 3:1 lindblad resonance .
this is relevant to the case of superhumps in su ursae majoris cataclysmic variables and other systems , where it is thought that this resonance leads to growth of eccentricity and a modulation in the light curve due to the interaction of a precessing eccentric disc with tidal stresses .
a single differential equation is formulated which describes the propagation , resonant excitation and viscous damping of eccentricity .
the theory is first worked out in the simple case of a narrow ring and leads to the conclusion that the eccentricity distribution is locally suppressed by the presence of the resonance , creating a dip in the eccentricity at the resonant radius .
application of this theory to the superhump case confirms this conclusion and produces a more accurate expression for the precession rate of the disc than has been previously accomplished with simple dynamical estimates .
accretion , accretion discs stars : dwarf novae . .
And you have already written the first three sentences of the full article: a superhump is a periodic variation in the luminosity of an accreting binary system , with a period close to the orbital period of the binary .
superhumps were first discovered in the su ursae majoris class of dwarf novae , where they occur during superoutbursts which are longer and more pronounced than common outbursts .
these usually show so - called normal or positive superhumps , where the superhump period is slightly longer than the orbital period ..
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negative superhumps , where the superhump period is shorter than the orbital period , have also been observed .
some other binary systems , such as v603 aquilae ( patterson & richman 1991 ) , have been described as permanent superhump systems , where the superhumps do not occur in outbursts but are instead variations in the normal lightcurve of the systems .
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12,792 |
Suppose that you have an abstract for a scientific paper: recent theoretical studies show that decoherence process can enhance transport efficiency in quantum systems .
this effect is known as environment - assisted quantum transport ( enaqt ) .
the role of enaqt in optimal quantum transport is well investigated , however , it is less known how robust enaqt is with respect to variations in the system or its environment characteristic . toward answering this question , we simulated excitonic energy transfer in fenna - matthews - olson ( fmo ) photosynthetic complex .
we found that enaqt is robust with respect to many relevant parameters of environmental interactions and frenkel - exciton hamiltonian including reorganization energy , bath frequency cutoff , temperature , and initial excitations , dissipation rate , trapping rate , disorders , and dipole moments orientations .
our study suggests that the enaqt phenomenon can be exploited in robust design of highly efficient quantum transport systems . .
And you have already written the first three sentences of the full article: quantum or coherent transport are common phenomena in many natural or artificial systems @xcite . in a quantum system ,
transfer of matter or energy is strongly influenced by structural disorder or environmental noise .
recently , it was discovered , in the context of energy transfer in photosynthetic complexes , that environmental interactions can have a constructive role in excitonic transport , called enaqt effect @xcite ..
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basically , a decoherence process can facilitate excitons displacement between molecules by breaking wavefunction localization @xcite , energy level broadening @xcite , or quantum jumps @xcite .
based on enaqt theory , optimal quantum transport is achieved by an optimal interplay of the system coherence and decoherence dynamics , influenced by the environment structure @xcite . the convergence of system - environment energy scales is an underlying principle for such an optimal transport process @xcite . in this paper , we study the role of enaqt in the robustness of quantum transport , a feature complement to optimality . to this end , as a model system , we consider excitonic energy transfer in fmo complex and investigate the efficiency of transport in the presence of large variations in internal and external conditions .
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12,793 |
Suppose that you have an abstract for a scientific paper: we present results of our study of correlated radio and x - ray emission in two black hole candidates and galactic microquasars grs 1915 + 105 and cyg x-1 in their steady long term hard states , along with cyg x-3 ( using data obtained from _ rossi x - ray timing explorer _ all - sky monitor [ _ rxte_-asm ] , _ compton gamma ray observatory _ burst and transient source experiment [ _ cgro_-batse ] , and green bank intereferometer [ gbi ] ) .
we detect a pivotal behavior in the x - ray spectrum of grs 1915 + 105 , correlated to the radio emission .
similar to the results obtained for cyg x-3 , the flux of x - rays softer than the pivoting point correlates with the radio emission , while the corresponding harder x - ray flux anti - correlates with both the radio and the softer x - ray emission , in this state .
we examine all the previously reported correlations of x - ray properties with the radio emission in galactic microquasars and argue that these are consistent with a general picture where a spectral pivoting is a common feature in these sources with the shape of the spectrum determining the flux of radio emission , during the hard states .
we also detect a general monotonic increase in the radio emission of these sources with the soft x - ray emission spanning about 5 orders of magnitude .
we qualitatively explain these findings with a two component advective flow model where the location of a boundary layer between the thin disk and the comptonizing region determines the spectral shape and also the amount of outflow . .
And you have already written the first three sentences of the full article: the ( quasi ) simultaneous observations of x - ray binaries in the radio and x - ray bands has led to the notion that the presence of radio jets is ubiquitous in sources with black holes or low magnetic field ( @xmath0 g ) neutron stars as compact objects ( see * ? ? ?
* ; * ? ? ?
galactic x - ray binaries exhibiting radio jets ( outflow of matter in a collimated beam ) , with both physical as well as temporal ( variability ) scale roughly at 6 orders of magnitude less than those of quasars , are termed as _ microquasars _ @xcite ..
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although superluminally moving radio jets are detected in several microquasars @xcite , which are invariably associated with huge radio flares , only recently it has been realized that non - thermal radio emission is a common feature during relatively quiet phases . @xcite made a detailed calculation of the energetics during such quiet phases and argues that the non - thermal emission forms a substantial part ( 5%50% ) of the energy budget .
compact radio jets are indeed observed in the low - hard state of several microquasars viz .
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12,794 |
Suppose that you have an abstract for a scientific paper: we study the rheology of confined suspensions of neutrally buoyant rigid monodisperse spheres in plane - couette flow using direct numerical simulations . we find that if the width of the channel is a ( small ) integer multiple of the sphere s diameter , the spheres self - organize into two - dimensional layers that slide on each other and the suspension s effective viscosity is significantly reduced .
each two - dimensional layer is found to be structurally liquid - like but their dynamics is frozen in time .
suspensions of solid objects in simple newtonian solvents ( e.g. , water ) can show a kaleidoscope of rheological behaviors depending on the shape , size , volume fraction ( @xmath0 ) of the additives , and the shear - rate ( @xmath1 ) imposed on the flow ; see , e.g. , refs .
@xcite for reviews .
suspensions can be of various types , e.g. , suspensions of small particles ( smaller than the viscous scale of the solvent ) , where the solvent plays the role of a thermal bath , are called brownian suspensions ( e.g. colloids ) @xcite . at small @xmath0 and under small @xmath1 , the effective viscosity of such suspensions increases with @xmath0 : @xmath2 @xcite , as derived by einstein @xcite ( see also ref .
@xcite for a @xmath3 dimensional generalization ) . in the other category
are suspensions of large particles ( e.g. emulsion , granular fluids etc . ) , where the thermal fluctuations are often negligible .
such suspensions are called _ non - brownian _ suspensions . for moderate values of @xmath0 and @xmath1 non - brownian
suspensions show _ continuous shear - thickening _ , ( i.e. , @xmath4 increases with @xmath1 ) @xcite which can be understood @xcite in terms of excluded volume effects .
such a rheological response has been observed in many natural and industrial flows , including flows of mud , lava , cement , and corn - starch solutions .
dense ( large @xmath0 , close to random close packing ) non - brownian suspensions may show _ discontinuous shear - thickening _ ....
And you have already written the first three sentences of the full article: lb and wf acknowledge financial support by the european research council grant no .
erc-2013-cog-616186 , tritos and computer time provided by snic ( swedish national infrastructure for computing ) .
dm acknowledges financial support from swedish research council under grant 2011 - 542 ( dm ) ..
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pc thanks nordita for hospitality .
25ifxundefined [ 1 ] ifx#1 ifnum [ 1 ] # 1firstoftwo secondoftwo ifx [ 1 ] # 1firstoftwo secondoftwo `` `` # 1''''@noop [ 0]secondoftwosanitize@url [ 0 ]
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12,795 |
Suppose that you have an abstract for a scientific paper: an extremely deep x - ray survey ( @xmath0 ms ) of the hubble deep field north and its environs ( @xmath1 arcmin@xmath2 ) has been performed with the advanced ccd imaging spectrometer on board the _ chandra x - ray observatory_. this is one of the two deepest x - ray surveys ever performed ; for point sources near the aim point it reaches 0.52.0 kev and 28 kev flux limits of @xmath3 erg @xmath4 s@xmath5 and @xmath6 erg @xmath4 s@xmath5 , respectively .
here we provide source catalogs along with details of the observations , data reduction , and technical analysis . observing conditions , such as background ,
were excellent for almost all of the exposure .
we have detected 370 distinct point sources : 360 in the 0.58.0 kev band , 325 in the 0.52.0 kev band , 265 in the 28 kev band , and 145 in the 48 kev band .
two new sources in the hdf - n itself are reported and discussed .
source positions are accurate to within 0.61.7@xmath7 ( at @xmath8% confidence ) depending mainly on the off - axis angle .
we also detect two highly significant extended x - ray sources and several other likely extended x - ray sources .
we present basic number count results for sources located near the center of the field .
source densities of @xmath9 deg@xmath10 ( at ) and @xmath11 deg@xmath10 ( at ) are observed in the soft and hard bands , respectively . .
And you have already written the first three sentences of the full article: we have performed a deep x - ray survey ( @xmath0 ms ) of the hubble deep field north (; williams et al .
1996 , hereafter w96 ; ferguson , dickinson , & williams 2000 ) and its environs with the _ chandra x - ray observatory _ ( hereafter ): the deep field north ( hereafter cdf - n ) survey .
this is one of the two deepest x - ray surveys ever conducted , the other being the deep field south survey ( e.g. , tozzi et al . 2001 ; p. rosati et al ..
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, in preparation ) .
near the aim point , the cdf - n observation reaches 0.52.0 kev and 28 kev limiting fluxes of @xmath3 erg @xmath4 s@xmath5 and @xmath6 erg @xmath4 s@xmath5 , respectively ; these flux limits are @xmath12 and @xmath13 times fainter than achieved by pre- missions . in figure 1
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12,796 |
Suppose that you have an abstract for a scientific paper: we consider the problem of distributed convergence to efficient outcomes in coordination games through dynamics based on aspiration learning . under aspiration learning , a player continues to play an action as long as the rewards received exceed a specified aspiration level . here , the aspiration level is a fading memory average of past rewards , and these levels also are subject to occasional random perturbations .
a player becomes dissatisfied whenever a received reward is less than the aspiration level , in which case the player experiments with a probability proportional to the degree of dissatisfaction .
our first contribution is the characterization of the asymptotic behavior of the induced markov chain of the iterated process in terms of an equivalent finite - state markov chain .
we then characterize explicitly the behavior of the proposed aspiration learning in a generalized version of coordination games , examples of which include network formation and common - pool games .
in particular , we show that in generic coordination games the frequency at which an efficient action profile is played can be made arbitrarily large .
although convergence to efficient outcomes is desirable , in several coordination games , such as common - pool games , attainability of fair outcomes , i.e. , sequences of plays at which players experience highly rewarding returns with the same frequency , might also be of special interest .
to this end , we demonstrate through analysis and simulations that aspiration learning also establishes fair outcomes in all symmetric coordination games , including common - pool games .
coordination games , aspiration learning , game theory 68t05 , 91a26 , 91a22 , 93e35 , 60j05 , 91a80 .
And you have already written the first three sentences of the full article: distributed coordination is of particular interest in many engineering systems .
two examples are distributed overlay routing or network formation @xcite and medium access control @xcite in wireless communications . in either case ,
nodes need to utilize their resources _ efficiently _ so that a desirable global objective is achieved ..
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for example , in network formation , nodes need to choose their immediate links so that connectivity is achieved with a minimum possible communication cost , i.e. , minimum number of links .
similarly , in medium access control , users need to establish a _
|
12,797 |
Suppose that you have an abstract for a scientific paper: an extended observation of the seyfert 1 galaxy in 2009 detected a photoionised outflow with a complex absorption line velocity structure and a broad correlation of velocity with ionisation parameter , shown in pounds ( 2011 ) to be consistent with a highly ionised , high velocity wind running into the interstellar medium or previous ejecta , losing much of its kinetic energy in the resultant strong shock . in the present paper
we examine the fek spectral region in more detail and find support for two distinct velocity components in the highly ionised absorber , with values corresponding to the putative fast wind ( @xmath00.12c ) and the post - shock flow ( v@xmath05000 - 7000 km s@xmath1 ) .
the fe k absorption line structure is seen to vary on a orbit - to - orbit timescale , apparently responding to both a short term increase in ionising flux and - perhaps more generally - to changes in the soft x - ray ( and simultaneous uv ) luminosity .
the latter result is particularly interesting in providing independent support for the existence of shocked gas being cooled primarily by compton scattering of accretion disc photons .
the fe k emission is represented by a narrow fluorescent line from near - neutral matter , with a weak red wing modelled here by a relativistic diskline .
the narrow line flux is quasi - constant throughout the 45-day 2009 campaign , but is resolved , with a velocity width consistent with scattering from a component of the post - shock flow .
evidence for a p cygni profile is seen in several individual orbit spectra for resonance transitions in both fe xxv and fe xxvi .
[ firstpage ] galaxies : active galaxies : seyfert : general galaxies : individual : ngc 4051 x - ray : galaxies .
And you have already written the first three sentences of the full article: an extended observation of the seyfert 1 galaxy in 2009 found a rich absorption line spectrum indicating a photoionised outflow with a wide range of velocities and ionisation parameter ( pounds 2011 ; hereafter paper i ) . the absorption line velocity structure and a broad correlation of velocity with ionisation parameter
were shown to be consistent with an outflow scenario where a highly ionised , high velocity wind , perhaps launched during intermittent super - eddington accretion ( king and pounds 2003 ) , runs into the interstellar medium or previous ejecta , losing much of its kinetic energy in the resultant strong shock .
the wider importance of such shocked outflows lies in the possibility that the accumulated thrust from multiple episodes - rather than the outflow energy - would eventually drive gas from the bulge , thereby limiting further star formation and black hole growth ..
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such a momentum - driven feedback mechanism has been shown by king ( 2003 , 2005 ) to reproduce the observed correlation of black hole and bulge mass ( e.g. ferrarese and merritt 2000 , gebhardt 2000 , haring and rix 2004 ) ) .
growing evidence for extreme velocity ( [email protected] - 0.2c ) x - ray outflows ( chartas 2002 , pounds 2003 , 2006 ; reeves 2003 , cappi 2006 , tombesi 2010 ) has been confined to the very highly ionised matter ( log@[email protected] ) most readily detected in the fe k band .
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12,798 |
Suppose that you have an abstract for a scientific paper: consider the dirichlet - to - neumann operator @xmath0 in the exterior problem for the 2d helmholtz equation outside a bounded domain with smooth boundary .
using parametrization of the boundary by normalized arclength , we treat @xmath0 as a pseudodifferential operator on the unit circle .
we study its discrete symbol .
we put forward a conjecture on the universal behaviour , independent of shape and curvature of the boundary , of the symbol as the wavenumber @xmath1 .
the conjecture is motivated by an explicit formula for circular boundary , and confirmed numerically for other shapes . it also agrees , on a physical level of rigor , with kirchhoff s approximation .
the conjecture , if true , opens new ways in numerical analysis of diffraction in the range of moderately high frequencies .
department of mathematics and statistics , + memorial university of newfoundland , [email protected] .
And you have already written the first three sentences of the full article: this work is a part of research aimed at an accurate and robust numerical algorithm for diffraction problems in mid - high frequency range , where the standard boundary integral equation methods fail due to large matrix size and , more importantly , to numerical contamination in quadratures .
a natural idea to use the knowledge of geometric phase and to separate fast oscillations from slowly varying amplitudes has been converted to a practical method @xcite,@xcite with recent enhancements @xcite .
a drawback of that approach occurs in the presence of flattening boundary regions , where kirchhoff s amplitude becomes singular . from numerical analyst.
Please generate the next two sentences of the article
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s point of view , a method that has problem with _ small _ curvature is anti - intuitive .
the point of our approach is to * look for an object in theory whose high - frequency asymptotics stands flattening well and is nt sensitive to convexity assumptions*. we suggest that the symbol of dirichlet - to - neumann operator might be such an object .
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12,799 |
Suppose that you have an abstract for a scientific paper: we present and discuss highly accurate photometry obtained through medium stromgren @xmath0 , @xmath1 bands and narrow [ oiii ] , h@xmath2 bands covering 500 days of the evolution of nova del 2013 since its maximum brightness .
this is by far the most complete study of any nova observed in such photometric systems .
the nova behaviour in these photometric bands is very different from that observed with the more conventional broad bands like @xmath3@xmath4@xmath5@xmath6@xmath7 or @xmath8 , providing unique information about extent and ionization of the ejecta , the onset of critical phases like the transition between optically thick and thin conditions , and re - ionization by the central super - soft x - ray source .
the actual transmission profiles of the @xmath0 , @xmath1 , [ oiii ] and h@xmath2 photometric filters have been accurately measured at different epochs and different illumination angles , to evaluate in detail their performance under exact operating conditions .
the extreme smoothness of both the h@xmath2 and [ oiii ] lightcurves argues for absence of large and abrupt discontinuities in the ejecta of nova del 2013 .
should they exist , glitches in the lightcurves would have appeared when the ionization and/or recombination fronts overtook them . during the period of recorded very large variability ( up to 100@xmath9 over a single day ) in the super - soft x - ray emission ( from day + 69 to + 86 past @xmath5 maximum ) , no glitch in excess of 1% was observed in the optical photometry , either in the continuum ( stromgren @xmath0 ) or in the lines ( [ oiii ] and h@xmath2 filters ) , or in a combination of the two ( stromgren @xmath1 , johnson @xmath4 and @xmath5 ) . considering that the recombination time scale in the ejecta was one week at that time ,
this excludes global changes of the white dwarf as the source of the x - ray variability and supports instead clumpy ejecta passing through the line of sight to us as its origin .
stars : novae - photometry .
And you have already written the first three sentences of the full article: the vast majority of the photometric observations carried out on novae at optical wavelengths has been obtained with johnson _ ubv _ and cousins @xmath6@xmath7 photometric systems .
the introduction of @xmath10 equatorial standards by landolt ( 1973 , 1983 , 1992 , 2009 ) , recently expanded to + 50@xmath11 declinations ( landolt 2013 ) , together with the almost exclusive use of ccds as detectors during the last 25 years , has brought more order and uniformity to the photometry of novae . in recent years , the sloan @xmath12 system ( fukugita et al .
1996 , smith et al ..
Please generate the next two sentences of the article
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2002 ) is being progressively introduced into leading observing facilities , and the amount of photometry of novae collected with this system is slowly increasing .
common to both the johnson - cousins and sloan systems is the large width of their photometric bands , that trades diagnostic capability with the appeal to reach fainter magnitudes .
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