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we study the time evolution of a high - momentum gluon or quark propagating through an infinite, thermalized, partonic medium utilizing a boltzmann equation approach. we calculate the collisional energy loss of the parton, study its temperature and flavor dependence as well as the the momentum broadening incurred through multiple interactions. our transport calculations agree well with analytic calculations of collisional energy - loss where available, but offer the unique opportunity to address the medium response as well in a consistent fashion.
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arxiv:1006.1668
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a novel method of spectroscopy in ion traps termed leak - out spectroscopy ( los ) is presented. here, mass selected, cold ions are excited by an infrared laser. in a subsequent collision with a neutral buffer gas particle their internal energy is then transferred to kinetic energy. as a result, these ions leak out from the ion trap and are detected. the los scheme is generally applicable, very sensitive and close to background free when operated at low temperature. the potential of this method is demonstrated and characterized here for the first time by recording the rotationally resolved spectrum of the c - h stretching vibration $ \ nu _ 1 $ of linear c $ _ 3 $ h $ ^ + $. besides performing high - resolution spectroscopy, this method opens up the way for analyzing the composition of trap content, e. g., determining isomer ratios, by selectively expelling isomers or other isobaric ions from the trap. likewise, los can be used to prepare clean samples of structural and nuclear spin isomers.
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arxiv:2209.13660
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the present paper concentrates on the analogues of rosenthal ' s inequalities for ordinary and decoupled bilinear forms in symmetric random variables. more specifically, we prove the exact moment inequalities for these objects in terms of moments of their individual components. as a corollary of these results we obtain the explicit expressions for the best constant in the analogues of rosenthal ' s inequality for ordinary and decoupled bilinear forms in identically distributed symmetric random variables in the case of the fixed number of random variables.
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arxiv:math/9909111
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a scheme for fast, compact, and controllable acceleration of heavy particles in vacuum has been recently proposed [ f. peano et al., new j. phys. 10 033028 ( 2008 ) ], wherein two counterpropagating laser beams with variable frequencies drive a beat - wave structure with variable phase velocity, leading to particle trapping and acceleration. the technique allows for fine control over the energy distribution and the total charge of the accelerated beam, to be obtained via tuning of the frequency variation. here, the theoretical bases of the acceleration scheme are described, and the possibility of applications to ultrafast muon acceleration and to the prompt extraction of cold - muon beams is discussed.
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arxiv:0807.2739
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we prove the existence of a unique large - data global - in - time weak solution to a class of models of the form $ \ mathbf { u } _ { tt } = \ mathrm { div } ( \ mathbb { t } ) + \ mathbf { f } $ for viscoelastic bodies exhibiting strain - limiting behaviour, where the constitutive equation, relating the linearised strain tensor $ \ boldsymbol { \ epsilon } ( \ mathbf { u } ) $ to the cauchy stress tensor $ \ mathbb { t } $, is assumed to be of the form $ \ boldsymbol { \ epsilon } ( \ mathbf { u } _ t ) + \ alpha \ boldsymbol { \ epsilon } ( \ mathbf { u } ) = f ( \ mathbb { t } ) $, where we define $ f ( \ mathbb { t } ) = ( 1 + | \ mathbb { t } | ^ a ) ^ { - \ frac { 1 } { a } } \ mathbb { t } $, for constant parameters $ \ alpha \ in ( 0, \ infty ) $ and $ a \ in ( 0, \ infty ) $, in any number $ d $ of space dimensions, with periodic boundary conditions. the cauchy stress $ \ mathbb { t } $ is show to belong to $ l ^ 1 ( q ) ^ { d \ times d } $ over the space - time domain $ q $. in particular, in three space dimensions, if $ a \ in ( 0, \ frac { 2 } { 7 } ) $, then in fact $ \ mathbb { t } \ in l ^ { 1 + \ delta } ( q ) ^ { d \ times d } $ for a $ \ delta > 0 $, the value of which depends only on $ a $.
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arxiv:2011.07490
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we compare the behavior of bond lengths, cross sectional shape and bulk modulus in equilibrium structure at ambient conditions and under hydrostatic pressure of all the three kinds of uncapped single walled carbon nanotubes. results of our numerical calculations show that two bond lengths completely describe the structure of achiral swnt whereas only one bond length is required to determine structure of chiral swnt. in armchair tubes, one bond length is found to be larger than that of graphitic value while in zigzag tubes one bond length has a constant value. these bond lengths are very sensitive to tube radius. in chiral tubes, the value of bond length is found to depend on the chirality and slightly on the tube radius. different responses of these bond lengths are found on application of pressure. at some critical pressure, both bond lengths become equal to each other in achiral tubes. an analysis regarding the cross sectional shape of the nanotubes and its pressure dependence has also been done. the shape transition, from circular to oval shape takes place. at this transition, the behavior of bond lengths is found different and dependent on the chirality of the tubes. chiral tubes with chiral angle which is mid way between zigzag and armchair tubes are found to have most prominent effects of chirality. thus we demonstrate that pressure is a useful probe to characterize various kinds of carbon nanotubes.
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arxiv:0812.4799
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in this work we report on the simultaneous measurement of the hydrodynamic coefficient and the electric charge of single { \ it bacillus subtilis } spores. the latter has great importance in protein binding to spores and in the adhesion of spores onto surfaces. the charge and the hydrodynamic coefficient were measured by an accurate procedure based on the analysis of the motion of single spores confined by an optical trap. the technique has been validated using charged spherical polystyrene beads. the excellent agreement of our results with the expected values demonstrates the quality of our procedure. we measured the charge of spores of { \ it b. subtilis } purified from a wild type strain and from two isogenic mutants characterized by an altered spore surface. our technique is able to discriminate the three spore types used, by their charge and by their hydrodynamic coefficient which is related to the hydrophobic properties of the spore surface.
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arxiv:1403.4384
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we present extensive ultraviolet ( uv ) and optical photometric and optical spectroscopic follow - up of supernova ( sn ) ~ 2021gno by the " precision observations of infant supernova explosions " ( poise ) project, starting less than two days after the explosion. given its intermediate luminosity, fast photometric evolution, and quick transition to the nebular phase with spectra dominated by [ ca ~ ii ] lines, sn ~ 2021gno belongs to the small family of calcium - rich transients. moreover, it shows double - peaked light curves, a phenomenon shared with only four other calcium - rich events. the projected distance from the center of the host galaxy is not as large as other objects in this family. the initial optical light - curve peaks coincide with a very quick decline of the uv flux, indicating a fast initial cooling phase. through hydrodynamical modelling of the bolometric light curve and line velocity evolution, we found that the observations are compatible with the explosion of a highly - stripped massive star with an ejecta mass of $ 0. 8 \, m _ \ odot $ and a $ ^ { 56 } $ ni mass of $ 0. 024 ~ m _ { \ odot } $. the initial cooling phase ( first light curve peak ) is explained by the presence of an extended circumstellar material comprising $ \ sim $ $ 10 ^ { - 2 } \, m _ { \ odot } $ with an extension of $ 1100 \, r _ { \ odot } $. we discuss if hydrogen features are present in both maximum - light and nebular spectra, and its implications in terms of the proposed progenitor scenarios for calcium - rich transients.
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arxiv:2309.07800
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hadronic observables in z + jet events can be subject to large nlo corrections at tev scales, with k - factors that even reach values of order 50 in some cases. we develop a method, loopsim, by which approximate nnlo predictions can be obtained for such observables, supplementing nlo z + jet and nlo z + 2 - jet results with a unitarity - based approximation for missing higher loop terms. we first test the method against known nnlo results for drell - yan lepton pt spectra. we then show our approximate nnlo results for the z + jet observables. finally we examine whether the loopsim method can provide useful information even in cases without giant k - factors, with results for observables in dijet events that can be compared to early lhc data.
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arxiv:1006.2144
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cyclic dominance of competing species is an intensively used working hypothesis to explain biodiversity in certain living systems, where the evolutionary selection principle would dictate a single victor otherwise. technically the may - - leonard models offer a mathematical framework to describe the mentioned non - transitive interaction of competing species when individual movement is also considered in a spatial system. emerging rotating spirals composed by the competing species are frequently observed character of the resulting patterns. but how do these spiraling patterns change when we vary the external environment which affects the general vitality of individuals? motivated by this question we suggest an off - lattice version of the tradition may - - leonard model which allows us to change the actual state of the environment gradually. this can be done by introducing a local carrying capacity parameter which value can be varied gently in an off - lattice environment. our results support a previous analysis obtained in a more intricate metapopulation model and we show that the well - known rotating spirals become evident in a benign environment when the general density of the population is high. the accompanying time - dependent oscillation of competing species can also be detected where the amplitude and the frequency show a scaling law of the parameter that characterizes the state of the environment. these observations highlight that the assumed non - transitive interaction alone is insufficient condition to maintain biodiversity safely, but the actual state of the environment, which characterizes the general living conditions, also plays a decisive role on the evolution of related systems.
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arxiv:2106.01857
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a fundamental task in modern cryptography is the joint computation of a function which has two inputs, one from alice and one from bob, such that neither of the two can learn more about the other ' s input than what is implied by the value of the function. in this letter, we show that any quantum protocol for the computation of a classical deterministic function that outputs the result to both parties ( two - sided computation ) and that is secure against a cheating bob can be completely broken by a cheating alice. whereas it is known that quantum protocols for this task cannot be completely secure, our result implies that security for one party implies complete insecurity for the other. our findings stand in stark contrast to recent protocols for weak coin tossing, and highlight the limits of cryptography within quantum mechanics. we remark that our conclusions remain valid, even if security is only required to be approximate and if the function that is computed for bob is different from that of alice.
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arxiv:1201.0849
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the second generation of robotic operating system, ros 2, has gained much attention for its potential to be used for safety - critical robotic applications. the need to provide a solid foundation for timing correctness and scheduling mechanisms is therefore growing rapidly. although there are some pioneering studies conducted on formally analyzing the response time of processing chains in ros 2, the focus has been limited to single - threaded executors, and multi - threaded executors, despite their advantages, have not been studied well. to fill this knowledge gap, in this paper, we propose a comprehensive response - time analysis framework for chains running on ros 2 multi - threaded executors. we first analyze the timing behavior of the default scheduling scheme in ros 2 multi - threaded executors, and then present priority - driven scheduling enhancements to address the limitations of the default scheme. our framework can analyze chains with both arbitrary and constrained deadlines and also the effect of mutually - exclusive callback groups. evaluation is conducted by a case study on nvidia jetson agx xavier and schedulability experiments using randomly - generated chains. the results demonstrate that our analysis framework can safely upper - bound response times under various conditions and the priority - driven scheduling enhancements not only reduce the response time of critical chains but also improve analytical bounds.
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arxiv:2408.08440
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recently, the authors of the current paper established in [ 9 ] the existence of a ground - state solution to the following bi - harmonic equation with the constant potential or rabinowitz potential : \ begin { equation } ( - \ delta ) ^ { 2 } u + v ( x ) u = f ( u ) \ \ text { in } \ \ mathbb { r } ^ { 4 }, \ end { equation } when the nonlinearity has the special form $ f ( t ) = t ( \ exp ( t ^ 2 ) - 1 ) $ and $ v ( x ) \ geq c > 0 $ is a constant or the rabinowitz potential. one of the crucial elements used in [ 9 ] is the fourier rearrangement argument. however, this argument is not applicable if $ f ( t ) $ is not an odd function. thus, it still remains open whether the above equation with the general critical exponential nonlinearity $ f ( u ) $ admits a ground - state solution even when $ v ( x ) $ is a positive constant. the first purpose of this paper is to develop a fourier rearrangement - free approach to solve the above problem. more precisely, we will prove that there is a threshold $ \ gamma ^ { * } $ such that for any $ \ gamma \ in ( 0, \ gamma ^ * ) $, the above equation with the constant potential $ v ( x ) = \ gamma > 0 $ admits a ground - state solution, while does not admit any ground - state solution for any $ \ gamma \ in ( \ gamma ^ { * }, + \ infty ) $. the second purpose of this paper is to establish the existence of a ground - state solution to the above equation with any degenerate rabinowitz potential $ v $ vanishing on some bounded open set. among other techniques, the proof also relies on a critical adams inequality involving the degenerate potential which is of its own interest.
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arxiv:2108.06301
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doping dependence of the electronic structure of la $ _ { 2 - x } $ sr $ _ x $ cuo $ _ 4 $ ( lsco ) has been systematically studied in a series of photoemission measurements. the unusual spectral features in the underdoped regime are attributed to the formation of dynamical stripes and the opening of large and small pseudogaps.
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arxiv:cond-mat/0011293
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in this work, we review and extend the so - called consistency conditions for the existence of a braneworld scenario in arbitrary dimensions in the brans - dicke ( bd ) gravitational theory. after that, we consider the particular case of a five - dimensional scenario which seems to have phenomenological interesting implications. we show that, in the bd framework, it is possible to achieve necessary conditions pointing to the possibility of accommodating branes with positive tensions in an ads bulk by the presence of the additional bd scalar field, avoiding in this way the necessity of including unstable objects in the compactification scheme. furthermore, in the context of time variable brane tension, it is shown that the brane tension may change its sign, following the bulk cosmological constant sign.
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arxiv:1001.1075
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estimating the depth of comics images is challenging as such images a ) are monocular ; b ) lack ground - truth depth annotations ; c ) differ across different artistic styles ; d ) are sparse and noisy. we thus, use an off - the - shelf unsupervised image to image translation method to translate the comics images to natural ones and then use an attention - guided monocular depth estimator to predict their depth. this lets us leverage the depth annotations of existing natural images to train the depth estimator. furthermore, our model learns to distinguish between text and images in the comics panels to reduce text - based artefacts in the depth estimates. our method consistently outperforms the existing state - ofthe - art approaches across all metrics on both the dcm and ebdtheque images. finally, we introduce a dataset to evaluate depth prediction on comics. our project website can be accessed at https : / / github. com / ivrl / comicsdepth.
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arxiv:2110.03575
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here we study the monr2 star forming region, which has a rich network of filaments joining in a star cluster forming hub, aiming at understanding the hub structure and to examine the mass fraction residing in the hub and in the filaments, which is a key factor that influences massive star formation. we conducted a multi - scale, multi - component analysis of the herschel column density maps ( resolution of 18. 2 " or $ \ sim $ 0. 07 pc at 830 pc ) of the region using a newly developed algorithm " getsf " to identify the structural components, namely, extended cloud, filaments, and sources. we find that cascades of lower column density filaments coalesce to form higher density filaments eventually merging inside the hub ( 0. 8 pc radius ). as opposed to the previous view of the hub as a massive clump with $ \ sim $ 1 pc radius, we find it to be a network of short high - density filaments. the total mass reservoir in the monr2 hfs ( 5 pc $ \ times $ 5 pc ) is split between filaments ( 54 % ), extended cloud ( 37 % ) and sources ( 9 % ). the m / l of filaments increase from $ \ sim $ 10 msun / pc at 1. 5pc from the hub to $ \ sim $ 100 msun / pc at its centre, while the number of filaments per annulus of 0. 2pc width decreases from 20 to 2 in the same range. the observed radial column density structure of the hfs ( filament component only ) displays a power - law dependence of $ n _ { \ mathrm { h } _ 2 } \ propto r ^ { - 2. 17 } $ up to a radius of $ \ sim $ 2. 5 pc from the central hub, resembling a global collapse of the hfs. we present a scenario where the hfs can be supported by magnetic fields which interact, merge and reorganize themselves as the filaments coalesce. in the new view of the hub as a network of high - density filaments, we suggest that only the stars located in the network can benefit from the longitudinal flows of gas to become massive, which may explain the reason for the formation of many low - mass stars in cluster centres.
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arxiv:2112.06803
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in this paper we prove that the pde $ p ( d ) f = q, $ where $ p $ and $ q $ are multivariate polynomials, has a solution in the space of polynomials of total degree not exceeding $ { n + s }, $ where $ n $ is the degree of $ q $ and $ s $ is the zero order of $ o = ( 0, \ ldots, 0 ) $ for $ p. $
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arxiv:2106.00272
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this survey gives an overview over different techniques used for pixel - level semantic segmentation. metrics and datasets for the evaluation of segmentation algorithms and traditional approaches for segmentation such as unsupervised methods, decision forests and svms are described and pointers to the relevant papers are given. recently published approaches with convolutional neural networks are mentioned and typical problematic situations for segmentation algorithms are examined. a taxonomy of segmentation algorithms is given.
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arxiv:1602.06541
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current developments in the statistics community suggest that modern statistics education should be structured holistically, that is, by allowing students to work with real data and to answer concrete statistical questions, but also by educating them about alternative frameworks, such as bayesian inference. in this article, we describe how we incorporated such a holistic structure in a bayesian research project on ordered binomial probabilities. the project was conducted with a group of three undergraduate psychology students who had basic knowledge of bayesian statistics and programming, but lacked formal mathematical training. the research project aimed to ( 1 ) convey the basic mathematical concepts of bayesian inference ; ( 2 ) have students experience the entire empirical cycle including collection, analysis, and interpretation of data and ( 3 ) teach students open science practices.
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arxiv:1810.07496
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we use the method of banerjee, banerjee and mitra and minimal homotopy paths to compute the consistent gauge anomaly for several superspace models of ssym coupled to matter. we review the derivation of the anomaly for n = 1 in four dimensions and then discuss the anomaly for two - dimensional models with ( 2, 0 ) supersymmetry.
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arxiv:hep-th/0009192
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we give a general framework for approximations to combinatorial assemblies, especially suitable to the situation where the number $ k $ of components is specified, in addition to the overall size $ n $. this involves a poisson process, which, with the appropriate choice of parameter, may be viewed as an extension of saddlepoint approximation. we illustrate the use of this by analyzing the component structure when the rank and size are specified, and the rank, $ r : = n - k $, is small relative to $ n $. there is near - universal behavior, in the sense that apart from cases where the exponential generating function has radius of convergence zero, for $ \ ell = 1, 2, \ dots $, when $ r \ asymp n ^ \ alpha $ for fixed $ \ alpha \ in ( \ frac { \ ell } { \ ell + 1 }, \ frac { \ ell + 1 } { \ ell + 2 } ) $, the size $ l _ 1 $ of the largest component converges in probabiity to $ \ ell + 2 $. further, when $ r \ sim t \, n ^ { \ ell / ( \ ell + 1 ) } $ for a positive integer $ \ ell $, and $ t \ in ( 0, \ infty ) $, $ \ mathbb { p } \, ( l _ 1 \ in \ { \ ell + 1, \ ell + 2 \ } ) \ to 1 $, with the choice governed by a poisson limit distribution for the number of components of size $ \ ell + 2 $. this was previously observed, for the case $ \ ell = 1 $ and the special cases of permutations and set partitions, using chen - stein approximations for the indicators of attacks and alignments, when rooks are placed randomly on a triangular board. the case $ \ ell = 1 $ is especially delicate, and was not handled by previous saddlepoint approximations.
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arxiv:1606.04642
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let us consider the following minimum problem \ [ \ lambda _ \ alpha ( p, r ) = \ min _ { \ substack { u \ in w _ { 0 } ^ { 1, p } ( - 1, 1 ) \ \ u \ not \ equiv0 } } \ dfrac { \ displaystyle \ int _ { - 1 } ^ { 1 } | u ' | ^ { p } dx + \ alpha \ left | \ int _ { - 1 } ^ { 1 } | u | ^ { r - 1 } u \, dx \ right | ^ { \ frac pr } } { \ displaystyle \ int _ { - 1 } ^ { 1 } | u | ^ { p } dx }, \ ] where $ \ alpha \ in \ mathbb r $, $ p \ ge 2 $ and $ \ frac p2 \ le r \ le p $. we show that there exists a critical value $ \ alpha _ c = \ alpha _ c ( p, r ) $ such that the minimizers have constant sign up to $ \ alpha = \ alpha _ { c } $ and then they are odd when $ \ alpha > \ alpha _ { c } $.
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arxiv:1902.04578
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we propose new activity - dependent adaptive boolean networks inspired by the cis - regulatory mechanism in gene regulatory networks. we analytically show that our model can be solved for stationary in - degree distribution for a wide class of update rules by employing the annealed approximation of boolean network dynamics and that evolved boolean networks have a preassigned average sensitivity that can be set independently of update rules if certain conditions are satisfied. in particular, when it is set to 1, our theory predicts that the proposed network rewiring algorithm drives boolean networks towards criticality. we verify that these analytic results agree well with numerical simulations for four representative update rules. we also discuss the relationship between sensitivity of update rules and stationary in - degree distributions and compare it with that in real - world gene regulatory networks.
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arxiv:1704.08586
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stars of spectral type oe are very rare. to date, only 13 oe stars have been identified within our galaxy. in this paper, we present six new oe stars and four new b0e stars found in lamost dr5. repeated spectral observations of the same oe stars show some emission line variability. the h $ \ beta $ emission of tyc 4801 - 17 - 1 shows rapid v / r variation. phase lags in the v / r ratio of tyc 4801 - 17 - 1 spectra are also seen. we found the unusual o4. 5 star rl 128 is an oe star with variable h $ \ alpha $ intensity and its ca ii triplet emission appears when h $ \ alpha $ emission reaches maximum intensity. these newly identified early type oe and b0e stars significantly increase the known sample.
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arxiv:1807.00574
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a new method is developed to design controllers in euclidean space for systems defined on manifolds. the idea is to embed the state - space manifold $ m $ of a given control system into some euclidean space $ \ mathbb r ^ n $, extend the system from $ m $ to the ambient space $ \ mathbb r ^ n $, and modify it outside $ m $ to add transversal stability to $ m $ in the final dynamics in $ \ mathbb r ^ n $. controllers are designed for the final system in the ambient space $ \ mathbb r ^ n $. then, their restriction to $ m $ produces controllers for the original system on $ m $. this method has the merit that only one single global cartesian coordinate system in the ambient space $ \ mathbb r ^ n $ is used for controller synthesis, and any controller design method in $ \ mathbb r ^ n $, such as the linearization method, can be globally applied for the controller synthesis. the proposed method is successfully applied to the tracking problem for the following two benchmark systems : the fully actuated rigid body system and the quadcopter drone system.
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arxiv:1807.03475
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let a and b be c * - algebras whose quotients are all rfd, and let c be a central c * - subalgebra in both a and b. we prove that the full amalgamated free product of a and b over c is then rfd. this generalizes korchagin ' s result that amalgamated free products of commutative c * - algebras are rfd. when applied to the case of a trivial amalgam, our methods recover the result of exel - loring for separable c * - algebras. as corollaries to our theorem, we give sufficient conditions for amalgamated free products of maximally almost periodic ( map ) groups to have rfd c * - algebras and hence to be map.
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arxiv:1809.09134
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##tyle 2 ^ { e } } has 2 n { \ displaystyle 2 ^ { n } } elements. = = = disjoint union = = = the disjoint union of two or more sets is similar to the union, but, if two sets have elements in common, these elements are considered as distinct in the disjoint union. this is obtained by labelling the elements by the indexes of the set they are coming from. the disjoint union of two sets a { \ displaystyle a } and b { \ displaystyle b } is commonly denoted a b { \ displaystyle a \ sqcup b } and is thus defined as a b = { ( a, i ) ( i = 1 ∧ a ∈ a ) ∨ ( i = 2 ∧ a ∈ b }. { \ displaystyle a \ sqcup b = \ { ( a, i ) \ mid ( i = 1 \ land a \ in a ) \ lor ( i = 2 \ land a \ in b \ }. } if a = b { \ displaystyle a = b } is a set with n { \ displaystyle n } elements, then a ∪ a = a { \ displaystyle a \ cup a = a } has n { \ displaystyle n } elements, while a a { \ displaystyle a \ sqcup a } has 2 n { \ displaystyle 2n } elements. the disjoint union of two sets is a particular case of the disjoint union of an indexed family of sets, which is defined as i ∈ i = { ( a, i ) i ∈ i ∧ a ∈ a i }. { \ displaystyle \ bigsqcup _ { i \ in { \ mathcal { i } } } = \ { ( a, i ) \ mid i \ in { \ mathcal { i } } \ land a \ in a _ { i } \ }. } the disjoint union is the coproduct in the category of sets. therefore the notation i ∈ i = { ( a, i ) i ∈ i ∧ a ∈ a i } { \ displaystyle \ coprod _ { i \ in { \ mathcal { i } } } = \ { ( a, i ) \ mid i \ in { \ mathcal { i } } \ land a \ in a _ { i } \ } } is commonly used. = = = = internal
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https://en.wikipedia.org/wiki/Set_(mathematics)
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we show for the first time that learning powerful representations from speech audio alone followed by fine - tuning on transcribed speech can outperform the best semi - supervised methods while being conceptually simpler. wav2vec 2. 0 masks the speech input in the latent space and solves a contrastive task defined over a quantization of the latent representations which are jointly learned. experiments using all labeled data of librispeech achieve 1. 8 / 3. 3 wer on the clean / other test sets. when lowering the amount of labeled data to one hour, wav2vec 2. 0 outperforms the previous state of the art on the 100 hour subset while using 100 times less labeled data. using just ten minutes of labeled data and pre - training on 53k hours of unlabeled data still achieves 4. 8 / 8. 2 wer. this demonstrates the feasibility of speech recognition with limited amounts of labeled data.
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arxiv:2006.11477
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recent studies point to the potential storage of a large number of patterns in the celebrated hopfield associative memory model, well beyond the limits obtained previously. we investigate the properties of new fixed points to discover that they exhibit instabilities for small perturbations and are therefore of limited value as associative memories. moreover, a large deviations approach also shows that errors introduced to the original patterns induce additional errors and increased corruption with respect to the stored patterns.
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arxiv:1704.07741
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we realize the two dimensional anti - de sitter ( $ ads _ 2 $ ) space as a kaluza - klein reduction of the $ ads _ 3 $ space in the framework of the discrete light cone quantization ( dlcq ). introducing dlcq coordinates which interpolate the original ( unboosted ) coordinates and the light cone coordinates, we discuss that $ ads _ 2 / cft $ correspondence can be deduced from the $ ads _ 3 / cft $. in particular, we elaborate on the deformation of wzw model to obtain the boundary theory for the $ ads _ 2 $ black hole. this enables us to derive the entropy of the $ ads _ 2 $ black hole from that of the $ ads _ 3 $ black hole.
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arxiv:hep-th/9906078
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the possibility of using axial spin color centers with $ s = 3 / 2 $, oriented along the hexagonal $ c $ axis in a silicon carbide ( sic ) wafer, has been demonstrated for all - optical measurement of projection of the external magnetic field coinciding with the $ c $ axis of the crystal, and the polar and azimuthal angles of the external measured magnetic field at room and significantly higher temperatures. a distinctive feature of spin centers in sic, in which optically induced spin alignment is carried out, is the presence of a unique system of spin levels in a magnetic field, caused by fine structure interaction and hyperfine interaction with the $ ^ { 29 } $ si nuclei and there is a wide range of level anticrossings ( lacs ), leading to an exceptionally strong change in photoluminescence in the region of lac and the dependence of the lac spectrum on the orientation of the external measured magnetic field, which made it possible to develop the all - optical vector magnetometry method. such measurements do not require microwave radiation, it is possible to use single spin center for the all - optical vector magnetometry. the proposed magnetometer is based on an external magnetic field cancellation scheme, which leads to a lac spectrum observed in a zero external magnetic field, called its reference spectrum, by maintaining a local region of zero magnetic field at the site of optical excitation of spin centers. 4h - sic plate is placed on the scanning stage of a confocal microscope inside the helmholtz coils. sensitivity to a constant magnetic field for $ z $ component of the magnetic field $ { b } _ { z } $ is better than $ 0. 1 \ mu $ t $ / \ sqrt { \ text { hz } } $ in a volume of $ 1 \ times10 ^ { - 8 } $ mm $ ^ { 3 } $ at room temperature. the sensitivity of determining the angles polar and azimuthal is determined by the sensitivity to determining the perpendicular component of the magnetic field, which is better than $ 5 ~ \ mu $ t $ / \ sqrt { \ text { hz } } $.
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arxiv:2404.07080
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in this paper we prove the well - posedness and we study the asymptotic behavior of nonoscillatory $ l ^ p $ - solutions for a third order nonlinear scalar differential equation. the equation consists of two parts : a linear third order with constant coefficients part and a nonlinear part represented by a polynomial of fourth order in three variables with variable coefficients. the results are obtained assuming three hypotheses : ( i ) the characteristic polynomial associated with the linear part has simple and real roots, ( ii ) the coefficients of the polynomial satisfy asymptotic integral smallness conditions, and ( iii ) the polynomial coefficients are in $ l ^ p ( [ t _ 0, \ infty [ ) $. these results are applied to study a fourth order linear differential equation of poincar \ ' e type and a fourth order linear differential equation with unbounded coefficients. moreover, we give some examples where the classical theorems can not be applied.
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arxiv:1611.08756
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we analyzed the longitudinal activity of nearly 7, 000 editors at the mega - journal plos one over the 10 - year period 2006 - 2015. using the article - editor associations, we develop editor - specific measures of power, activity, article acceptance time, citation impact, and editorial renumeration ( an analogue to self - citation ). we observe remarkably high levels of power inequality among the plos one editors, with the top - 10 editors responsible for 3, 366 articles - - corresponding to 2. 4 % of the 141, 986 articles we analyzed. such high inequality levels suggest the presence of unintended incentives, which may reinforce unethical behavior in the form of decision - level biases at the editorial level. our results indicate that editors may become apathetic in judging the quality of articles and susceptible to modes of power - driven misconduct. we used the longitudinal dimension of editor activity to develop two panel regression models which test and verify the presence of editor - level bias. in the first model we analyzed the citation impact of articles, and in the second model we modeled the decision time between an article being submitted and ultimately accepted by the editor. we focused on two variables that represent social factors that capture potential conflicts - of - interest : ( i ) we accounted for the social ties between editors and authors by developing a measure of repeat authorship among an editor ' s article set, and ( ii ) we accounted for the rate of citations directed towards the editor ' s own publications in the reference list of each article he / she oversaw. our results indicate that these two factors play a significant role in the editorial decision process. moreover, these two effects appear to increase with editor age, which is consistent with behavioral studies concerning the evolution of misbehavior and response to temptation in power - driven environments.
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arxiv:1701.04906
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the radius of the mbh sphere of influence and $ r _ { \ rm eff, nsc } $. nscs harbouring a sufficiently massive black hole are likely to exhibit surface brightness profile deviating from a typical king profile.
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arxiv:1601.02613
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congenital heart disease is considered as one the most common groups of congenital malformations which affects $ 6 - 11 $ per $ 1000 $ newborns. in this work, an automated framework for detection of cardiac anomalies during ultrasound screening is proposed and evaluated on the example of hypoplastic left heart syndrome ( hlhs ), a sub - category of congenital heart disease. we propose an unsupervised approach that learns healthy anatomy exclusively from clinically confirmed normal control patients. we evaluate a number of known anomaly detection frameworks together with a model architecture based on the $ \ alpha $ - gan network and find evidence that the proposed model performs significantly better than the state - of - the - art in image - based anomaly detection, yielding average $ 0. 81 $ auc \ emph { and } a better robustness towards initialisation compared to previous works.
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arxiv:2012.03679
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we show that the 3 user m _ t x m _ r mimo interference channel has d ( m, n ) = min ( m / ( 2 - 1 / k ), n / ( 2 + 1 / k ) ) degrees of freedom ( dof ) normalized by time, frequency, and space dimensions, where m = min ( m _ t, m _ r ), n = max ( m _ t, m _ r ), k = ceil { m / ( n - m ) }. while the dof outer bound is established for every m _ t, m _ r value, the achievability is established in general subject to normalization with respect to spatial - extensions. given spatial - extensions, the achievability relies only on linear beamforming based interference alignment schemes with no need for time / frequency extensions. in the absence of spatial extensions, we show through examples how essentially the same scheme may be applied over time / frequency extensions. the central new insight to emerge from this work is the notion of subspace alignment chains as dof bottlenecks. the dof value d ( m, n ) is a piecewise linear function of m, n, with either m or n being the bottleneck within each linear segment. the corner points of these piecewise linear segments correspond to a = { 1 / 2, 2 / 3, 3 / 4,... } and b = { 1 / 3, 3 / 5, 5 / 7,... }. the set a contains all values of m / n and only those for which there is redundancy in both m and n. the set b contains all values of m / n and only those for which there is no redundancy in either m or n. our results settle the feasibility of linear interference alignment, introduced by cenk et al., for the 3 user m _ t x m _ r mimo interference channel, completely for all values of m _ t, m _ r. specifically, the linear interference alignment problem ( m _ t x m _ r, d ) ^ 3 ( as defined in previous work by cenk et al. ) is feasible if and only if d < = floor { d ( m, n ) }. with and only with the exception of the values m / n \ in b, we show that for every m / n value there are proper systems that are not feasible. our results show that m / n \ in a are the only values for which
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arxiv:1109.4350
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the oblique random survival forest ( rsf ) is an ensemble supervised learning method for right - censored outcomes. trees in the oblique rsf are grown using linear combinations of predictors to create branches, whereas in the standard rsf, a single predictor is used. oblique rsf ensembles often have higher prediction accuracy than standard rsf ensembles. however, assessing all possible linear combinations of predictors induces significant computational overhead that limits applications to large - scale data sets. in addition, few methods have been developed for interpretation of oblique rsf ensembles, and they remain more difficult to interpret compared to their axis - based counterparts. we introduce a method to increase computational efficiency of the oblique rsf and a method to estimate importance of individual predictor variables with the oblique rsf. our strategy to reduce computational overhead makes use of newton - raphson scoring, a classical optimization technique that we apply to the cox partial likelihood function within each non - leaf node of decision trees. we estimate the importance of individual predictors for the oblique rsf by negating each coefficient used for the given predictor in linear combinations, and then computing the reduction in out - of - bag accuracy. in general benchmarking experiments, we find that our implementation of the oblique rsf is approximately 450 times faster with equivalent discrimination and superior brier score compared to existing software for oblique rsfs. we find in simulation studies that ' negation importance ' discriminates between relevant and irrelevant predictors more reliably than permutation importance, shapley additive explanations, and a previously introduced technique to measure variable importance with oblique rsfs based on analysis of variance. methods introduced in the current study are available in the aorsf r package.
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arxiv:2208.01129
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in the context of surgery, robots can provide substantial assistance by performing small, repetitive tasks such as suturing, needle exchange, and tissue retraction, thereby enabling surgeons to concentrate on more complex aspects of the procedure. however, existing surgical task learning mainly pertains to rigid body interactions, whereas the advancement towards more sophisticated surgical robots necessitates the manipulation of soft bodies. previous work focused on tissue phantoms for soft tissue task learning, which can be expensive and can be an entry barrier to research. simulation environments present a safe and efficient way to learn surgical tasks before their application to actual tissue. in this study, we create a robot operating system ( ros ) - compatible physics simulation environment with support for both rigid and soft body interactions within surgical tasks. furthermore, we investigate the soft tissue interactions facilitated by the patient - side manipulator of the davinci surgical robot. leveraging the pybullet physics engine, we simulate kinematics and establish anchor points to guide the robotic arm when manipulating soft tissue. using demonstration - guided reinforcement learning ( rl ) algorithms, we investigate their performance in comparison to traditional reinforcement learning algorithms. our in silico trials demonstrate a proof - of - concept for autonomous surgical soft tissue retraction. the results corroborate the feasibility of learning soft body manipulation through the application of reinforcement learning agents. this work lays the foundation for future research into the development and refinement of surgical robots capable of managing both rigid and soft tissue interactions. code is available at https : / / github. com / amritpal - 001 / tissue _ retract.
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arxiv:2309.00837
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in recent years, significant advances have been made in the field of game research. however, there has been a noticeable dearth of scholarly research focused on the domain of dynamics, despite the widespread recognition among researchers of its existence and importance. the objective of this paper is to address this research gap by presenting a vocabulary dedicated to boardgame dynamics. to achieve this goal, we employ a focus group to generate a set of dynamic concepts that are subsequently subjected to validation and refinement through a survey. the resulting concepts are then organized into a vocabulary using a taxonomic structure, allowing the grouping of these concepts into broader and more general ideas.
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arxiv:2403.10267
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we study the problem of calculating noncommutative distances on graphs, using techniques from linear algebra, specifically, birkhoff - james orthogonality. a complete characterization of the solutions is obtained in the case when the underlying graph is a path.
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arxiv:2409.04146
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we give the addition formula for the tropical hesse pencil, which is the tropicalization of the hesse pencil parametrized by the level - three theta functions, via those for the ultradiscrete theta functions. the ultradiscrete theta functions are reduced from the level - three theta functions through the procedure of ultradiscretization by choosing their parameters appropriately. the parametrization of the level - three theta functions firstly introduced in \ cite { kknt09 } gives an explicit correspondence between the amoeba of the real part of the hesse cubic curve and the tropical hesse curve. moreover, through the parametrization, we obtain the subtraction - free forms of the addition formulae for the level - three theta functions, which lead to the addition formula for the tropical hesse pencil in terms of the ultradiscretization. using the parametrization, the tropical counterpart of the hesse configuration is also given.
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arxiv:1512.08063
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we consider scalar local operators of the determinant type in the conformal ` ` fishnet ' ' theory that arises as a limit of gamma - deformed $ \ mathcal { n } = 4 $ super yang - mills theory. we generalise a field - theory approach to expand their correlation functions to arbitrary order in the small coupling constants and apply it to the bi - scalar reduction of the model. we explicitly analyse the two - point functions of determinants, as well as of certain deformations with the insertion of scalar fields, and describe the feynman - graph structure of three - and four - point correlators with single - trace operators. these display the topology of globe and spiral graphs, which are known to renormalise single - trace operators, but with ` ` alternating ' ' boundary conditions. in the appendix material we further investigate a four - point function of two determinants and the shortest bi - local single trace. we resum the diagrams by the bethe - salpeter method and comment on the exchanged ope states.
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arxiv:2110.09458
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this talk summarizes some theoretical features and experimental implications of a general lorentz - violating extension of the minimal su ( 3 ) x su ( 2 ) x u ( 1 ) standard model that allows for both cpt - even and cpt - odd effects. the theory would arise as the low - energy limit of a fundamental theory that is lorentz and cpt covariant but in which spontaneous lorentz breaking occurs. the use of neutral - meson oscillations and various qed systems to bound the apparent cpt and lorentz violations is described.
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arxiv:hep-ph/9810352
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food and drink awards § food technology awards = = general references = = hans - jurgen bassler und frank lehmann : containment technology : progress in the pharmaceutical and food processing industry. springer, berlin 2013, isbn 978 - 3642392917 = = references = = = = external links = = media related to food technology at wikimedia commons
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https://en.wikipedia.org/wiki/Food_technology
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we examine properties of ttbar candidates events in lepton + jets final states to establish the helicities of the w bosons in t - > w + b decays. our analysis is based on a direct calculation of a probability that each event corresponds to a ttbar final state, as a function of the helicity of the w boson. we use the 125 events / pb sample of data collected by the do experiment during run i of the fermilab tevatron collider at sqrt { s } = 1. 8 tev, and obtain a longitudinal helicity fraction of f _ 0 = 0. 56 + / - 0. 31, which is consistent with the prediction of f _ 0 = 0. 70 from the standard model.
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arxiv:hep-ex/0404040
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the rosseland mean opacity of dust in protoplanetary disks is often calculated assuming the interstellar medium ( ism ) size distribution and a constant dust - to - gas ratio. however, the dust size distribution and the dust - to - gas ratio in protoplanetary disks are distinct from those of the ism. here, we use simple dust evolution models that incorporate grain growth and transport to calculate the time evolution of mean opacity of dust grains as a function of distance from the star. dust dynamics and size distribution are sensitive to the assumed value of the turbulence strength $ \ alpha _ { \ rm t } $ and the velocity at which grains fragment $ v _ { \ rm frag } $. for moderate - to - low turbulence strengths of $ \ alpha _ { \ rm t } \ lesssim 10 ^ { - 3 } $ and substantial differences in $ v _ { \ rm frag } $ for icy and ice - free grains, we find a spatially non - uniform dust - to - gas ratio and grain size distribution that deviate significantly from the ism values, in agreement with previous studies. the effect of a non - uniform dust - to - gas ratio on the rosseland mean opacity dominates over that of the size distribution. this spatially varying - - that is non - monotonic - - dust - to - gas ratio creates a region in the protoplanetary disk that is optimal for producing hydrogen - rich planets, potentially explaining the apparent peak in gas giant planet occurrence rate at intermediate distances. the enhanced dust - to - gas ratio within the ice line also suppresses gas accretion rates onto sub - neptune cores, thus stifling their tendency to undergo runaway gas accretion within disk lifetimes. finally, our work corroborates the idea that low mass cores with large primordial gaseous envelopes ( ` super - puffs ' ) originate beyond the ice line.
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arxiv:2101.10333
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we present a comparison between the rotation period distributions of solar - type single stars and primary stars in close binaries ( 0. 1 au ~ < a ~ < 5 au ) in the young ( 150 myr ) open cluster m35 ( ngc 2168 ). we find that the primary stars in the close binaries rotate faster than the single stars, on average. the differences in the means and medians between the period distributions are statistically significant at the 99. 9 % level or higher. the faster rotation among the primary stars in close binaries is not due to tidal synchronization as tidally evolved stars are excluded from the comparison. we discuss this result in the context of different early - evolution accretion processes and star - disk interactions for single stars and stars in close binaries.
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arxiv:0707.1087
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strongly dipolar mesogenic compounds with a chiral center located in a lateral alkyl chain were synthesized, and shown to form the ferroelectric nematic phase. the presence of molecular chirality induced a helical structure in both the n and nf phases, but with opposite helix sense in the two phases. the relaxation frequency of the polar fluctuations was found to be lower for the chiral nf phase than for its achiral, non - branched counterpart with the same lateral chain length.
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arxiv:2112.11887
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leveraging human grasping skills to teach a robot to perform a manipulation task is appealing, but there are several limitations to this approach : time - inefficient data capture procedures, limited generalization of the data to other grasps and objects, and inability to use that data to learn more about how humans perform and evaluate grasps. this paper presents a data capture protocol that partially addresses these deficiencies by asking participants to specify ranges over which a grasp is valid. the protocol is verified both qualitatively through online survey questions ( where 95. 38 % of within - range grasps are identified correctly with the nearest extreme grasp ) and quantitatively by showing that there is small variation in grasps ranges from different participants as measured by joint angles, contact points, and position. we demonstrate that these grasp ranges are valid through testing on a physical robot ( 93. 75 % of grasps interpolated from grasp ranges are successful ).
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arxiv:1607.03366
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listing and counting triangles in graphs is a key algorithmic kernel for network analyses including community detection, clustering coefficients, k - trusses, and triangle centrality. we design and implement a new serial algorithm for triangle counting that performs competitively with the fastest previous approaches on both real and synthetic graphs, such as those from the graph500 benchmark and the mit / amazon / ieee graph challenge. the experimental results use the recently - launched intel xeon platinum 8480 + and cpu max 9480 processors.
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arxiv:2309.09064
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##ediment to up - stream navigation, and there are generally variations in water level, and when the discharge becomes small in the dry season. it is impossible to maintain a sufficient depth of water in the low - water channel. the possibility to secure uniformity of depth in a river by lowering the shoals obstructing the channel depends on the nature of the shoals. a soft shoal in the bed of a river is due to deposit from a diminution in velocity of flow, produced by a reduction in fall and by a widening of the channel, or to a loss in concentration of the scour of the main current in passing over from one concave bank to the next on the opposite side. the lowering of such a shoal by dredging merely effects a temporary deepening, for it soon forms again from the causes which produced it. the removal, moreover, of the rocky obstructions at rapids, though increasing the depth and equalizing the flow at these places, produces a lowering of the river above the rapids by facilitating the efflux, which may result in the appearance of fresh shoals at the low stage of the river. where, however, narrow rocky reefs or other hard shoals stretch across the bottom of a river and present obstacles to the erosion by the current of the soft materials forming the bed of the river above and below, their removal may result in permanent improvement by enabling the river to deepen its bed by natural scour. the capability of a river to provide a waterway for navigation during the summer or throughout the dry season depends on the depth that can be secured in the channel at the lowest stage. the problem in the dry season is the small discharge and deficiency in scour during this period. a typical solution is to restrict the width of the low - water channel, concentrate all of the flow in it, and also to fix its position so that it is scoured out every year by the floods which follow the deepest part of the bed along the line of the strongest current. this can be effected by closing subsidiary low - water channels with dikes across them, and narrowing the channel at the low stage by low - dipping cross dikes extending from the river banks down the slope and pointing slightly up - stream so as to direct the water flowing over them into a central channel. = = estuarine works = = the needs of navigation may also require that a stable, continuous, navigable channel is prolonged from the navigable river to deep water at the mouth of the estuary. the interaction of river
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https://en.wikipedia.org/wiki/River_engineering
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graph visualization is a vital component in many real - world applications ( e. g., social network analysis, web mining, and bioinformatics ) that enables users to unearth crucial insights from complex data. lying in the core of graph visualization is the node distance measure, which determines how the nodes are placed on the screen. a favorable node distance measure should be informative in reflecting the full structural information between nodes and effective in optimizing visual aesthetics. however, existing node distance measures yield sub - par visualization quality as they fall short of these requirements. moreover, most existing measures are computationally inefficient, incurring a long response time when visualizing large graphs. to overcome such deficiencies, we propose a new node distance measure, pdist, geared towards graph visualization by exploiting a well - known node proximity measure, personalized pagerank. moreover, we propose an efficient algorithm tau - push for estimating pdist under both single - and multi - level visualization settings. with several carefully - designed techniques, tau - push offers non - trivial theoretical guarantees for estimation accuracy and computation complexity. extensive experiments show that our proposal significantly outperforms 13 state - of - the - art graph visualization solutions on 12 real - world graphs in terms of both efficiency and effectiveness ( including aesthetic criteria and user feedback ). in particular, our proposal can interactively produce satisfactory visualizations within one second for billion - edge graphs.
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arxiv:2112.14944
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a detailed description of the activation - relaxation technique ( art ) is presented. this method defines events in the configurational energy landscape of disordered materials, such as a - si, glasses and polymers, in a two - step process : first, a configuration is activated from a local minimum to a nearby saddle - point ; next, the configuration is relaxed to a new minimum ; this allows for jumps over energy barriers much higher than what can be reached with standard techniques. such events can serve as basic steps in equilibrium and kinetic monte carlo schemes.
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arxiv:cond-mat/9710023
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we have constructed a model which describes the optical emission from ultraluminous x - ray sources ( ulxs ), and have used it to constrain the parameters of seven ulx systems. our model assumes a binary nature for ulxs, and accounts for optical emission from an x - ray irradiated companion star and accretion disk. we apply our model to six different ulx optical counterparts observed with hst, and one observed with the eso vlt, and determine the mass, radius and age of the donor stars in these systems. in addition, we obtained constraints for the black hole ( bh ) mass in some cases. we use the mass accretion rate implied by the x - ray luminosity of these sources as an additional constraint on the donor star, by assuming the mass transfer is driven by the stellar nuclear evolution. we find that in general the donors are older and less massive than previously thought, and are consistent with being of spectral type b. we discuss how these results affect our understanding of the evolution and history of ulxs. where we can constrain the bh masses, we find them to be consistent with stellar mass bhs or intermediate mass bhs of order 100 solar masses. we make predictions for future observations of optical / infrared ulx counterparts, calculating binary periods for different bh masses in each of the seven sources.
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arxiv:astro-ph/0701764
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linear waves in bounded inviscid fluids do not generally form normal modes with regular eigenfunctions. examples are provided by inertial waves in a rotating fluid contained in a spherical annulus, and internal gravity waves in a stratified fluid contained in a tank with a non - rectangular cross - section. for wave frequencies in the ranges of interest, the inviscid linearized equations are spatially hyperbolic and their characteristic rays are typically focused on to wave attractors. when these systems experience periodic forcing, for example of tidal origin, the response of the fluid can become localized in the neighbourhood of a wave attractor. in this paper i define a prototypical problem of this form and construct analytically the long - term response to a periodic body force in the asymptotic limit of small viscosity. the vorticity of the fluid is localized in a detached shear layer close to the wave attractor in such a way that the total rate of dissipation of energy is asymptotically independent of the viscosity. i further demonstrate that the same asymptotic dissipation rate is obtained if a non - viscous damping force is substituted for the navier - stokes viscosity. i discuss the application of these results to the problem of tidal forcing in giant planets and stars, where the excitation and dissipation of inertial waves may make a dominant, or at least important, contribution to the orbital and spin evolution.
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arxiv:astro-ph/0506450
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we report on the first detailed measurements of electron backscattering from low z targets at energies up to 124 kev. both energy and angular distributions of the backscattered electrons are measured and compared with electron transport simulations based on the geant4 and penelope monte carlo simulation codes. comparisons are also made with previous, less extensive, measurements and with measurements at lower energies.
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arxiv:nucl-ex/0310002
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we investigate the cghs model through numerical calculation. the behavior of the mass function, which we introduced in our previous work as a ` ` local mass ' ', is examined. we found that the mass function takes negative values, which means that the amount of hawking radiation becomes greater than the initial mass of the black hole as in the case of the rst model.
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arxiv:hep-th/9409039
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defects intentionally introduced into magnetic materials often have a profound effect on the physical properties. specifically tailored neutron spectroscopic experiments can provide detailed information on both the local exchange interactions and the local distances between the magnetic atoms around the defects. this is demonstrated for manganese dimer excitations observed for the magnetically diluted three -, two - and one - dimensional compounds kmnxzn1 - xf3, k2mnxzn1 - xf4 and csmnxmg1 - xbr3, respectively, with x = 0. 10. the resulting local exchange interactions deviate up to 10 % from the average, and the local mn - mn distances are found to vary stepwise with increasing internal chemical pressure due to the mn / zn or mn / mg substitution. our analysis qualitatively supports the theoretically predicted decay of atomic displacements according to 1 / r * * 2, 1 / r and constant ( for three -, two - and one - dimensional compounds, respectively ) where r denotes the distance of the displaced atoms from the defect.
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arxiv:1510.00570
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many real - world phenomena can be modeled as a graph, making them extremely valuable due to their ubiquitous presence. gnns excel at capturing those relationships and patterns within these graphs, enabling effective learning and prediction tasks. gnns are constructed using multi - layer perceptrons ( mlps ) and incorporate additional layers for message passing to facilitate the flow of features among nodes. it is commonly believed that the generalizing power of gnns is attributed to the message - passing mechanism between layers, where nodes exchange information with their neighbors, enabling them to effectively capture and propagate information across the nodes of a graph. our technique builds on these results, modifying the message - passing mechanism further : one by weighing the messages before accumulating at each node and another by adding residual connections. these two mechanisms show significant improvements in learning and faster convergence
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arxiv:2311.15448
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the recent success of transformer models in language, such as bert, has motivated the use of such architectures for multi - modal feature learning and tasks. however, most multi - modal variants ( e. g., vilbert ) have limited themselves to visual - linguistic data. relatively few have explored its use in audio - visual modalities, and none, to our knowledge, illustrate them in the context of granular audio - visual detection or segmentation tasks such as sound source separation and localization. in this work, we introduce tribert - - a transformer - based architecture, inspired by vilbert, which enables contextual feature learning across three modalities : vision, pose, and audio, with the use of flexible co - attention. the use of pose keypoints is inspired by recent works that illustrate that such representations can significantly boost performance in many audio - visual scenarios where often one or more persons are responsible for the sound explicitly ( e. g., talking ) or implicitly ( e. g., sound produced as a function of human manipulating an object ). from a technical perspective, as part of the tribert architecture, we introduce a learned visual tokenization scheme based on spatial attention and leverage weak - supervision to allow granular cross - modal interactions for visual and pose modalities. further, we supplement learning with sound - source separation loss formulated across all three streams. we pre - train our model on the large music21 dataset and demonstrate improved performance in audio - visual sound source separation on that dataset as well as other datasets through fine - tuning. in addition, we show that the learned tribert representations are generic and significantly improve performance on other audio - visual tasks such as cross - modal audio - visual - pose retrieval by as much as 66. 7 % in top - 1 accuracy.
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arxiv:2110.13412
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the main focus of this thesis is the ir spectral regime, which since the 70 ' s and 80 ' s has revolutionised our understanding of the universe. a multi - wavelength analysis on extremely red galaxy populations is first presented in one of the most intensively observed patch of the sky, the chandra deep field south. by adopting a purely statistical methodology, we consider all the photometric and spectroscopic information available on large samples of extremely red objects ( eros, 553 sources ), irac eros ( ieros, 259 sources ), and distant red galaxies ( drgs, 289 sources ). we derive general properties : redshift distributions, agn host fraction, star - formation rate densities, dust content, morphology, mass functions and mass densities. the results point to the fact that eros, ieros, and drgs all belong to the same population, yet seen at different phases of galaxy evolution. the second part of this thesis is dedicated to the agn selection in the ir, with particular relevance to the james webb space telescope, to be launched in 2018. we develop an improved ir criterion ( using k and irac bands ) as an alternative to existing ir agn criteria for the z < 2. 5 regime, and develop another ir criterion which reliably selects agn hosts at 0 < z < 7 ( using k, spitzer - irac, and spitzer - mips24um bands, kim ). the ability to track agn activity since the end of reionization holds great advantages for the study of galaxy evolution. the thesis then focus on the importance of dust. based on deep ir data on the cosmological survey, we derive rest - frame 1. 6, 3. 3, and 6. 2um luminosity functions and their dependency on redshift. we estimate the dust contribution to those wavelengths and show that the hot dust luminosity density evolves since z = 1 - 2 with a much steeper drop than the star - formation history of the universe. future prospects are finally discussed in the last chapter.
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arxiv:1110.2787
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the out - of - phase soliton distribution of the wave field was found for a multicore fiber ( mcf ) from an even number of cores located in a ring. its stability is proved both with respect to small wave field perturbations, including azimuthal ones and to small deformations of the mcf structure. as an example of using this soliton distribution, the problem of laser pulse compression in an active mcf is studied. the optimal fiber parameters, the minimum duration of the output pulse, and the compression length have been found, which are in good agreement with the results of numerical simulation. in order to achieve high energies in the output laser pulse, the requirements for mcf deformations are determined.
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arxiv:1909.05149
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in this article we consider structures on a fano plane $ { \ cal f } $ which allow a generalisation of freudenthal ' s construction of a norm and a bilinear multiplication law on an eight - dimensional vector space $ { \ mathbb o _ { \ cal f } } $ canonically associated to $ { \ cal f } $. we first determine necessary and sufficient conditions in terms of the incidence geometry of $ { \ cal f } $ for these structures to give rise to division composition algebras, and classify the corresponding structures using a logarithmic version of the multiplication. we then show how these results can be used to deduce analogous results in the split composition algebra case.
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arxiv:2203.03261
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in this work we investigate three variants of single amplification - stage detector elements ; they comprise thgem electrodes closed at their bottom with metallic or resistive anodes to form well - type configurations. we present the results of a comparative study of the thick - well ( thwell ), resistive - well ( rwell ) and segmented resistive well ( srwell ), focusing on their performance in terms of spark - quenching capability, gain variation with position and counting rate, pulse shapes and signal propagation to neighboring readout pads ; the study included both 30x30 and 100x100 mm $ ^ 2 $ detectors. it was shown that the well structures with resistive anodes offer stable operation even in a highly ionizing environment, with effective spark quenching, as well as higher gain than the standard thgem / induction - gap configuration. cross talk between neighboring readout pads was shown to be effectively eliminated in the segmented detector with a conductive grid underneath the resistive layer. the latter multiplier should allow for the design of very thin detectors, e. g. sampling elements in digital hadronic calorimeters planned for experiments in future linear colliders.
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arxiv:1310.6183
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a detailed theoretical and numerical investigation of the infinitesimal single - crystal gradient plasticity and grain - boundary theory of gurtin ( 2008 ) " a theory of grain boundaries that accounts automatically for grain misorientation and grain - boundary orientation ". journal of the mechanics and physics of solids 56 ( 2 ), 640 - 662, is performed. the governing equations and flow laws are recast in variational form. the associated incremental problem is formulated in minimization form and provides the basis for the subsequent finite element formulation. various choices of the kinematic measure used to characterize the ability of the grain boundary to impede the flow of dislocations are compared. an alternative measure is also suggested. a series of three - dimensional numerical examples serve to elucidate the theory.
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arxiv:1505.01822
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we present a new estimate of the fine structure constant and the $ \ beta $ - function of qed at an arbitrary scale. using the non - perturbative but convergent series expression of the one loop effective action of qed that has been available recently we make a non - perturbative estimate of the running coupling and the $ \ beta $ - function, and prove the renormalization group invariance of the effective action. the contrast between our result and the perturbative result is remarkable.
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arxiv:hep-th/0010073
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this paper introduces a novel method to simultaneously super - resolve and colour - predict images acquired by snapshot mosaic sensors. these sensors allow for spectral images to be acquired using low - power, small form factor, solid - state cmos sensors that can operate at video frame rates without the need for complex optical setups. despite their desirable traits, their main drawback stems from the fact that the spatial resolution of the imagery acquired by these sensors is low. moreover, chromatic mapping in snapshot mosaic sensors is not straightforward since the bands delivered by the sensor tend to be narrow and unevenly distributed across the range in which they operate. we tackle this drawback as applied to chromatic mapping by using a residual channel attention network equipped with a texture sensitive block. our method significantly outperforms the traditional approach of interpolating the image and, afterwards, applying a colour matching function. this work establishes state - of - the - art in this domain while also making available to the research community a dataset containing 296 registered stereo multi - spectral / rgb images pairs.
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arxiv:1909.02221
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evolutionary algorithms ( ea ), a class of stochastic search methods based on the principles of natural evolution, have received widespread acclaim for their exceptional performance in various real - world optimization problems. while researchers worldwide have proposed a wide variety of eas, certain limitations remain, such as slow convergence speed and poor generalization capabilities. consequently, numerous scholars actively explore improvements to algorithmic structures, operators, search patterns, etc., to enhance their optimization performance. reinforcement learning ( rl ) integrated as a component in the ea framework has demonstrated superior performance in recent years. this paper presents a comprehensive survey on integrating reinforcement learning into the evolutionary algorithm, referred to as reinforcement learning - assisted evolutionary algorithm ( rl - ea ). we begin with the conceptual outlines of reinforcement learning and the evolutionary algorithm. we then provide a taxonomy of rl - ea. subsequently, we discuss the rl - ea integration method, the rl - assisted strategy adopted by rl - ea, and its applications according to the existing literature. the rl - assisted procedure is divided according to the implemented functions including solution generation, learnable objective function, algorithm / operator / sub - population selection, parameter adaptation, and other strategies. additionally, different attribute settings of rl in rl - ea are discussed. in the applications of rl - ea section, we also demonstrate the excellent performance of rl - ea on several benchmarks and a range of public datasets to facilitate a quick comparative study. finally, we analyze potential directions for future research.
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arxiv:2308.13420
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in this paper, we propose a new way to approach qudit systems using toric geometry and related topics including the local mirror symmetry used in the string theory compactification. we refer to such systems as ( n, d ) quantum systems where $ n $ and $ d $ denote the number of the qudits and the basis states respectively. concretely, we first relate the ( n, d ) quantum systems to the holomorphic sections of line bundles on n dimensional projective spaces cp ^ { n } with degree n ( d - 1 ). these sections are in one - to - one correspondence with d ^ n integral points on a n - dimensional simplex. then, we explore the local mirror map in the toric geometry language to establish a linkage between the ( n, d ) quantum systems and type ii d - branes placed at singularities of local calabi - yau manifolds. ( 1, d ) and ( 2, d ) are analyzed in some details and are found to be related to the mirror of the ale space with the a _ { d - 1 } singularity and a generalized conifold respectively.
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arxiv:1408.3952
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we analyze the point decomposition problem ( pdp ) in binary elliptic curves. it is known that pdp in an elliptic curve group can be reduced to solving a particular system of multivariate non - linear system of equations derived from the so called semaev summation polynomials. we modify the underlying system of equations by introducing some auxiliary variables. we argue that the trade - off between lowering the degree of semaev polynomials and increasing the number of variables is worth.
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arxiv:1504.02347
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we study the existence of infinite - dimensional invariant tori in a mechanical system of infinitely many rotators weakly interacting with each other. we consider explicitly interactions depending only on the angles, with the aim of discussing in a simple case the analyticity properties to be required on the perturbation of the integrable system in order to ensure the persistence of a large measure set of invariant tori with finite energy. the proof we provide of the persistence of the invariant tori implements the renormalization group scheme based on the tree formalism - - i. e. the graphical representation of the solutions of the equations of motion in terms of trees - - which has been widely used in finite - dimensional problems. the method is very effectual and flexible : it naturally extends, once the functional setting has been fixed, to the infinite - dimensional case with only minor technical - natured adaptations.
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arxiv:2404.09025
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we numerically investigate the stress distribution of a paste when an external oscillation is applied. the paste memorizes the oscillation as plastic deformation. due to the plastic deformation, the residual stress remains after the oscillation, where the residual stress distribution depends on the number of cycles in the oscillation. as this number increases, the symmetry of the stress distribution is enhanced, which is consistent with the crack patterns observed in the experiments using a drying paste.
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arxiv:2012.14675
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the renormalization of a quadratic - like map is studied. the three - dimensional yoccoz puzzle for an infinitely renormalizable quadratic - like map is discussed. for an unbranched quadratic - like map having the { \ sl a priori } complex bounds, the local connectivity of its julia set is proved by using the three - dimensional yoccoz puzzle. the generalized version of sullivan ' s sector theorem is discussed and is used to prove his result that the feigenbaum quadratic polynomial has the { \ sl a priori } complex bounds and is unbranched. a dense subset on the boundary of the mandelbrot set is constructed so that for every point of the subset, the corresponding quadratic polynomial is unbranched and has the { \ sl a priori } complex bounds.
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arxiv:math/9511208
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we use the dressed potentials obtained in the adiabatic representation of two coupled channels to calculate s - wave feshbach resonances in a 3d spherically symmetric potential with an open channel interacting with a closed channel. analytic expressions for the s - wave scattering length $ a $ and number of resonances are obtained for a piecewise constant model with a piecewise constant interaction of the open and closed channels near the origin. we show analytically and numerically that, for strong enough coupling strength, feshbach resonances can exist even when the closed channel does { \ em not } have a bound state.
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arxiv:1410.0323
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cosmological models in lyra ' s geometry are constructed and investigated with the assumption of a minimal interaction of matter with the displacement vector field and the dynamical $ \ lambda $ - term. exact solutions of the model equations are obtained for the different equations of state of the matter, that fills the universe, and for the certain assumptions on the decaying law for $ \ lambda $.
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arxiv:1207.5476
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madam is a cmb map - making code, designed to make temperature and polarization maps of time - ordered data of total power experiments like planck. the algorithm is based on the destriping technique, but it also makes use of known noise properties in the form of a noise prior. the method in its early form was presented in an earlier work by keihanen et al. ( 2005 ). in this paper we present an update of the method, extended to non - averaged data, and include polarization. in this method the baseline length is a freely adjustable parameter, and destriping can be performed at a different map resolution than that of the final maps. we show results obtained with simulated data. this study is related to planck lfi activities.
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arxiv:0907.0367
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an obstacle representation of a plane graph g is v ( g ) together with a set of opaque polygonal obstacles such that g is the visibility graph on v ( g ) determined by the obstacles. we investigate the problem of computing an obstacle representation of a plane graph ( orpg ) with a minimum number of obstacles. we call this minimum size the obstacle number of g. first, we show that orpg is np - hard by reduction from planar vertex cover, resolving a question posed by [ 8 ]. second, we give a reduction from orpg to maximum degree 3 planar vertex cover. since this reduction preserves solution values, it follows that orpg is fixed parameter tractable ( fpt ) and admits a polynomial - time approximation scheme ( ptas ).
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arxiv:1107.4624
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the recent progress in dna sequencing will probably revolutionize the world of electronic. hence, we went from dna sequencing that only research centers could realize, to portable, tiny and inexpensive tools. so, it is likely that in a few years these dna sequencers will be included in our smartphones. the purpose of this paper is to support this revolution, by using the dna cryptography, hash functions and social networks. the first application will introduce a mutual entity authentication protocol in order to help waifs, refugees, and victims of human trafficking to find their biological parents online. the second application will also use the dna cryptography and the social networks to protect whistleblowers ' actions. for example, this method will allow whistleblowers to securely broadcast on social networks, their information with one grape.
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arxiv:1606.06644
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in engineering, macro - engineering ( alternatively known as mega engineering ) is the implementation of large - scale design projects. it can be seen as a branch of civil engineering or structural engineering applied on a large landmass. in particular, macro - engineering is the process of marshaling and managing of resources and technology on a large scale to carry out complex tasks that last over a long period. in contrast to conventional engineering projects, macro - engineering projects ( called macro - projects or mega - projects ) are multidisciplinary, involving collaboration from all fields of study. because of the size of macro - projects they are usually international. macro - engineering is an evolving field that has only recently started to receive attention. because we routinely deal with challenges that are multinational in scope, such as global warming and pollution, macro - engineering is emerging as a transcendent solution to worldwide problems. macro - engineering is distinct from megascale engineering due to the scales where they are applied. where macro - engineering is currently practical, mega - scale engineering is still within the domain of speculative fiction because it deals with projects on a planetary or stellar scale. = = projects = = macro engineering examples include the construction of the panama canal and the suez canal. = = planned projects = = examples of projects include the channel tunnel and the planned gibraltar tunnel. two intellectual centers focused on macro - engineering theory and practice are the candida oancea institute in bucharest, and the center for macro projects and diplomacy at roger williams university in bristol, rhode island. = = see also = = = = references = = frank p. davidson and kathleen lusk brooke, building the world : an encyclopedia of the great engineering projects in history, two volumes ( greenwood publishing group, oxford uk, 2006 ) v. badescu, r. b. cathcart and r. d. schuiling, macro - engineering : a challenge for the future ( springer, the netherlands, 2006 ) r. b. cathcart, v. badescu with ramesh radhakrishnan, ( 2006 ) : macro - engineers ' dreams archived 2013 - 10 - 24 at the wayback machine pdf, 175pp. accessed 24 may 2013 alexander bolonkin and richard b. cathcart, macro - projects ( nova publishing, 2009 ) viorel badescu and r. b. cathcart, macro - engineering seawater ( springer, 2010 ), 880 pages. r. b. cathcart, macro - imagineering our dosmozoicum. ( lambert academic publishing,
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https://en.wikipedia.org/wiki/Macro-engineering
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the multipurpose detector ( mpd ) consists of a typical array of sub - detectors to study the nuclear matter originating from the collisions of beams provided by the nuclotron - based ion collider facility ( nica ). a beam monitoring detector ~ ( bebe ) is proposed for stage 2 of mpd to increase the trigger capabilities. bebe is constituted of two plastic scintillator disks segmented in 80 cells $ \ pm ~ 2 ~ m $ away from the interaction point of mpd. laboratory measurements to obtain the energy resolution of an individual bebe cell prototype are presented. it is shown that an energy resolution of $ 22 \ pm6 \ % $ can be obtained. based on monte carlo simulations, the trigger efficiencies of the bebe are presented for p + p collisions at 11 ~ gev considering a threshold in the energy loss of the charged particles reaching the detector.
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arxiv:2305.17847
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in an effort to search for ly $ \ alpha $ emission from circum - and intergalactic gas on scales of hundreds of kpc around $ z \ sim3 $ quasars, and thus characterise the physical properties of the gas in emission, we have initiated an extensive fast - survey with the multi unit spectroscopic explorer ( muse ) : quasar snapshot observations with muse : search for extended ultraviolet emission ( qso museum ). in this work, we report the discovery of an enormous ly $ \ alpha $ nebula ( elan ) around the quasar sdss ~ j102009. 99 + 104002. 7 at $ z = 3. 164 $, which we followed - up with deeper muse observations. this elan spans $ \ sim297 $ projected kpc, has an average ly $ \ alpha $ surface brightness $ { \ rm sb } _ { \ rm ly \ alpha } \ sim 6. 04 \ times10 ^ { - 18 } $ erg s $ ^ { - 1 } $ cm $ ^ { - 2 } $ arcsec $ ^ { - 2 } $ ( within the $ 2 \ sigma $ isophote ), and is associated with an additional four, previously unknown embedded sources : two ly $ \ alpha $ emitters and two faint active galactic nuclei ( one type - 1 and one type - 2 quasar ). by mapping at high significance the line - of - sight velocity in the entirety of the observed structure, we unveiled a large - scale coherent rotation - like pattern spanning $ \ sim300 $ km s $ ^ { - 1 } $ with a velocity dispersion of $ < 270 $ km s $ ^ { - 1 } $, which we interpret as a signature of the inspiraling accretion of substructures within the quasar ' s host halo. future multiwavelength data will complement our muse observations, and are definitely needed to fully characterise such a complex system. none the less, our observations reveal the potential of new sensitive integral - field spectrographs to characterise the dynamical state of diffuse gas on large scales in the young universe, and thereby witness the assembly of galaxies.
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arxiv:1709.08228
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an almost - stationary gauge condition is proposed with a view to numerical relativity applications. the time lines are defined as the integral curves of the timelike solutions of the harmonic almost - killing equation. this vector equation is derived by a variational principle, by minimizing the deviations from isometry. the corresponding almost - stationary gauge condition allows one to put the field equations in hyperbolic form, both in the free - evolution adm and in the z4 formalisms.
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arxiv:gr-qc/0509015
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active network management ( anm ) of electricity distribution networks include many complex stochastic sequential optimization problems. these problems need to be solved for integrating renewable energies and distributed storage into future electrical grids. in this work, we introduce gym - anm, a framework for designing reinforcement learning ( rl ) environments that model anm tasks in electricity distribution networks. these environments provide new playgrounds for rl research in the management of electricity networks that do not require an extensive knowledge of the underlying dynamics of such systems. along with this work, we are releasing an implementation of an introductory toy - environment, anm6 - easy, designed to emphasize common challenges in anm. we also show that state - of - the - art rl algorithms can already achieve good performance on anm6 - easy when compared against a model predictive control ( mpc ) approach. finally, we provide guidelines to create new gym - anm environments differing in terms of ( a ) the distribution network topology and parameters, ( b ) the observation space, ( c ) the modelling of the stochastic processes present in the system, and ( d ) a set of hyperparameters influencing the reward signal. gym - anm can be downloaded at https : / / github. com / robinhenry / gym - anm.
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arxiv:2103.07932
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the stability of the multiple equilibrium states of a hexagram ring with six curved sides is investigated. each of the six segments is a rod having the same length and uniform natural curvature. these rods are bent uniformly in the plane of the hexagram into equal arcs of 120deg or 240deg and joined at a cusp where their ends meet to form a 1 - loop planar ring. the 1 - loop rings formed from 120deg or 240deg arcs are inversions of one another and they, in turn, can be folded into a 3 - loop straight line configuration or a 3 - loop ring with each loop in an " 8 " shape. each of these four equilibrium states has a uniform bending moment. two additional intriguing planar shapes, 6 - circle hexagrams, with equilibrium states that are also uniform bending, are identified and analyzed for stability. stability is lost when the natural curvature falls outside the upper and lower limits in the form of a bifurcation mode involving coupled out - of - plane deflection and torsion of the rod segments. conditions for stability, or lack thereof, depend on the geometry of the rod cross - section as well as its natural curvature. rods with circular and rectangular cross - sections will be analyzed using a specialized form of kirchhoff rod theory, and properties will be detailed such that all four of the states of interest are mutually stable. experimental demonstrations of the various states and their stability are presented. part ii presents numerical simulations of transitions between states using both rod theory and a three - dimensional finite element formulation, includes confirmation of the stability limits established in part i, and presents additional experimental demonstrations and verifications.
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arxiv:2307.06543
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we give a combinatorial description of the composition factors of the induction product of two evaluation modules of the affine iwahori - hecke algebra of type gl ( m ). using quantum affine schur - weyl duality, this yields a combinatorial description of the composition factors of the tensor product of two evaluation modules of the quantum affine algebra of type sl ( n ).
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arxiv:math/0401077
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the need for quantitative characterization of the solar energetic particle ( sep ) dynamics goes beyond being an academic discipline only. it has numerous practical implications related to human activity in space. the terrestrial magnetic field shields the international space station ( iss ) and most uncrewed missions from exposure to sep radiation. however, extreme sep events with hard energy spectra are particularly rich in hundreds of mev to several gev protons that can reach the altitudes of the low earth orbit ( leo ). these protons have a high penetrating capability, thus producing significant radiation hazards for human spaceflight. seps also have a significant effect on the atmosphere. sudden ionization of the upper atmosphere at high latitudes that occurs during polar cap absorption ( pca ) events can block high frequency ( hf ) communication for hours, affecting communication with aircraft on intercontinental high - altitude flights. another effect of seps in the atmosphere is creating nox molecules in the upper atmosphere that can deplete the atmospheric ozone population. the paper also presents an analysis of ( 1 ) how various pitch angle diffusion coefficient approximations affect the properties of the simulated seps population and ( 2 ) discusses how pitch angle scattering when seps are beyond 1 au affects a sep event decay phase at the earth ' s orbit.
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arxiv:2209.09346
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brownian dynamics of dirac fermions in twisted bilayer graphene is investigated within the framework of semiclassical relativistic langevin equations. we find that under the influence of orthogonal, commensurate ac drives in the periodic ratchet potential of a substrate, the charge carriers in the system exhibit pronounced random dynamics, tuned by the twist angle, making twisted bilayer graphene distinguishable from monolayer graphene. it is shown that as threshold twist angle matches the optimal angle, deterministic running states appear in the limit of weak thermal noise where the diffusion rate is enhanced significantly compared to bare thermal diffusion. analysis of the real space trajectories and diffusion coefficient illustrates the significant role of thermal noise in the random motion of dirac fermions. in addition, we find that the brownian particle shows remarkable ratchet effect as a net current.
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arxiv:2306.10312
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in this study we give the hyperbolic version of classical menelaus theorem for quadrilaterals.
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arxiv:1105.0397
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in computer science, an integer is a datum of integral data type, a data type that represents some range of mathematical integers. integral data types may be of different sizes and may or may not be allowed to contain negative values. integers are commonly represented in a computer as a group of binary digits ( bits ). the size of the grouping varies so the set of integer sizes available varies between different types of computers. computer hardware nearly always provides a way to represent a processor register or memory address as an integer. = = value and representation = = the value of an item with an integral type is the mathematical integer that it corresponds to. integral types may be unsigned ( capable of representing only non - negative integers ) or signed ( capable of representing negative integers as well ). an integer value is typically specified in the source code of a program as a sequence of digits optionally prefixed with + or −. some programming languages allow other notations, such as hexadecimal ( base 16 ) or octal ( base 8 ). some programming languages also permit digit group separators. the internal representation of this datum is the way the value is stored in the computer ' s memory. unlike mathematical integers, a typical datum in a computer has some minimal and maximum possible value. the most common representation of a positive integer is a string of bits, using the binary numeral system. the order of the memory bytes storing the bits varies ; see endianness. the width, precision, or bitness of an integral type is the number of bits in its representation. an integral type with n bits can encode 2n numbers ; for example an unsigned type typically represents the non - negative values 0 through 2n − 1. other encodings of integer values to bit patterns are sometimes used, for example binary - coded decimal or gray code, or as printed character codes such as ascii. there are four well - known ways to represent signed numbers in a binary computing system. the most common is two ' s complement, which allows a signed integral type with n bits to represent numbers from −2 ( n−1 ) through 2 ( n−1 ) − 1. two ' s complement arithmetic is convenient because there is a perfect one - to - one correspondence between representations and values ( in particular, no separate + 0 and −0 ), and because addition, subtraction and multiplication do not need to distinguish between signed and unsigned types. other possibilities include offset binary, sign - magnitude, and ones ' complement. some computer languages define integer
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https://en.wikipedia.org/wiki/Integer_(computer_science)
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studies of cool white dwarfs in the solar neighbourhood have placed a limit on the age of the galactic disk of 8 - 9 billion years. however, determining their cooling ages requires the knowledge of their effective temperatures, masses, radii, and atmospheric composition. so far, these parameters could only be inferred for a small number of ultracool white dwarfs for which an accurate distance is known, by fitting their spectral energy distributions ( seds ) in conjunction with a theoretical mass - radius relation. however, the mass - radius relation remains largely untested, and the derived cooling ages are hence model - dependent. here we report direct measurements of the mass and radius of an ultracool white dwarf in the double - lined eclipsing binary sdss j013851. 54 - 001621. 6. we find m ( wd ) = 0. 529 + / - 0. 010msol and r ( wd ) = 0. 0131 + / - 0. 0003rsol. our measurements are consistent with the mass - radius relation and we determine a robust cooling age of 9. 5 billion years for the 3570k white dwarf. we find that the mass and radius of the low mass companion star, m ( sec ) = 0. 132 + / - 0. 003msol and r ( sec ) = 0. 165 + / - 0. 001rsol, are in agreement with evolutionary models. we also find evidence that this > 9. 5 gyr old m5 star is still active, far beyond the activity lifetime for a star of its spectral type. this is likely caused by the high tidally - enforced rotation rate of the star. the companion star is close to filling its roche lobe and the system will evolve into a cataclysmic variable in only 70 myr. our direct measurements demonstrate that this system can be used to calibrate ultracool white dwarf atmospheric models.
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arxiv:1207.5393
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we provide a geometric interpretation of the local contribution of a line to the count of lines on a quintic threefold over a field k of characteristic not equal to 2, that is, we define the type of a line on a quintic threefold and show that it coincides with the local index at the corresponding zero of the section of sym ^ 5 s ^ * - > gr ( 2, 5 ) defined by the threefold. furthermore, we define the dynamic euler number which allows us to compute the a ^ 1 - euler number as the sum of local contributions of zeros of a section with non - isolated zeros which deform with a general deformation. as an example we provide a quadratic count of 2875 distinguished lines on the fermat quintic threefold which computes the dynamic euler number of sym ^ 5 s ^ * - > gr ( 2, 5 ). combining those two results we get that the sum of the types of lines on a general quintic threefold is 1445 < 1 > + 1430 < - 1 > in gw ( k ) when k is a field of characteristic not equal to 2 or 5.
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arxiv:2006.12089
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we analyze the effect of plasma screening on nuclear reaction rates in dense matter composed of atomic nuclei of one or two types. we perform semiclassical calculations of the coulomb barrier penetrability taking into account a radial mean field potential of plasma ions. the mean field potential is extracted from the results of extensive monte carlo calculations of radial pair distribution functions of ions in binary ionic mixtures. we calculate the reaction rates in a wide range of plasma parameters and approximate these rates by an analytical expression that is expected to be applicable for multicomponent ions mixtures. also, we analyze gamow - peak energies of reacting ions in various nuclear burning regimes. for illustration, we study nuclear burning in c - o mixtures.
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arxiv:0905.3844
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the women ' s health initiative randomized clinical trial of hormone therapy found no benefit of hormones in preventive cardiovascular disease, a finding in striking contrast with a large body of observational research. understanding whether better methodology and / or statistical adjustment might have prevented the erroneous conclusions of observational research is important. this is a re - analysis of data from a case - control study examining the relationship of postmenopausal hormone therapy and the risks of myocardial infarction ( mi ) and ischemic stroke in which we reported no overall increase or decrease in the risk of either event. variables measuring health behavior / lifestyle that are not likely to be causally with the risks of mi and stroke ( e. g., sunscreen use ) were included in multivariate analysis along with traditional confounders ( age, hypertension, diabetes, smoking, body mass index, ethnicity, education, prior coronary heart disease for mi and prior stroke / tia for stroke ) to determine whether adjustment for the health behavior / lifestyle variables could reproduce or bring the results closer to the findings in a large and definitive randomized clinical trial of hormone therapy, the women ' s health initiative. for both mi and stroke, measures of health behavior / lifestyle were associated with odds ratios ( ors ) less than 1. 0. adjustment for traditional cardiovascular disease confounders did not alter the magnitude of the ors for mi or stroke. addition of a subset of these variables selected using stepwise regression to the final mi or stroke models along with the traditional cardiovascular disease confounders moved the ors for estrogen and estrogen / progestin use closer to values observed in the women health initiative clinical trial, but did not reliably reproduce the clinical trial results for these two endpoints.
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arxiv:0805.2845
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let $ k $ be an imaginary quadratic field, and let $ \ mathfrak { f } $ be a nontrivial integral ideal of $ k $. hasse and ramachandra asked whether the ray class field of $ k $ modulo $ \ mathfrak { f } $ can be generated by a single value of the weber function. we completely resolve this question when $ \ mathfrak { f } = ( n ) $ for an integer $ n > 1 $.
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arxiv:1608.06705
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let $ g $ be a countable group that is the fundamental group of a graph of groups with finite edge groups and vertex groups that satisfy the strong atiyah conjecture over $ k \ subseteq \ mathbb { c } $ a field closed under complex conjugation. assume that the orders of finite subgroups of $ g $ are bounded above. we show that $ g $ satisfies the strong atiyah conjecture over $ k $. in particular, this implies that the strong atiyah conjecture is closed under free products. moreover, we prove that the $ \ ast $ - regular closure of $ k [ g ] $ in $ \ mathcal { u } ( g ) $, $ \ mathcal { r } _ { \ small k [ g ] } $, is a universal localization of the graph of rings associated to the graph of groups, where the rings are the corresponding $ \ ast $ - regular closures. as a result, we obtain that the algebraic and center - valued atiyah conjecture over $ k $ are also closed under the graph of groups construction provided that the edge groups are finite. we also infer some consequences on the structure of the $ k _ 0 $ and $ k _ 1 $ - groups of $ \ mathcal { r } _ { \ small k [ g ] } $. the techniques developed allow us to prove that $ k [ g ] $ fulfills the strong, algebraic and center - valued atiyah conjectures and that $ \ mathcal { r } _ { \ small k [ g ] } $ is the universal localization of $ k [ g ] $ over the set of all matrices that become invertible in $ \ mathcal { u } ( g ) $ if $ g $ lies in a certain class of groups $ \ mathcal { t } _ { \ small \ mathcal { vli } } $, which contains in particular virtually - { locally indicable } groups that are the fundamental group of a graph of virtually free groups.
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arxiv:2409.12268
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in contrast to the many continuous global optimization methods that assume the objective function and constraints are factorable, we study how to find globally maximal solutions to problems that are not factorable, focusing on a particular class of problems. specifically, we develop a method for non - decreasing continuous submodular functions subject to constraints. we characterize the hypograph of such functions and develop a cutting plane algorithm that finds approximate solutions and bounds using an approximation of the convex hull of the hypograph. we also test a spatial branch - and - bound approach that utilizes the approximate cutting plane algorithm to form an outer approximation and obtain upper bounds for a sub - rectangle and compare our method with a state - of - the - art commercial solver. the main result is that for some problems the property of submodularity is more useful than factorability.
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arxiv:2208.13886
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in this paper we extend the hkll holographic smearing function method to reconstruct ( quasi ) local ads bulk scalar observables in the background of a large ads black hole formed by null shell collapse ( a " pure state " black hole ), from the dual cft which is undergoing a sudden quench. in particular, we probe the near horizon and sub - horizon bulk locality. first we construct local bulk operators from the cft in the leading semiclassical limit, $ n \ rightarrow \ infty $. then we look at effects due to the finiteness of $ n $, where we propose a suitable coarse - graining prescription involving early and late time cut - offs to define semiclassical bulk observables which are approximately local ; their departure from locality being non - perturbatively small in $ n $. our results have important implications on the black hole information problem.
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arxiv:1505.03895
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it is shown that ions can be accelerated to mev energy range in the direction perpendicular to the magnetic field by the exb mechanism of electrostatic waves. the acceleration occurs in discrete steps of duration being a small fraction the gyroperiod and can explain observations of ion energization to 10 kev at quasi - perpendicular shocks and to 100 - 1000 kev at quasi - parallel shocks. a general expression is provided for the maximum energy of ions accelerated in shocks of arbitrary configuration. the waves involved in the acceleration are related to three cross - field current - driven instabilities : the lower hybrid drift ( lhd ) instability induced by the density gradients in shocks and shocklets, followed by the modified two - stream ( mts ) and electron cyclotron drift ( ecd ) instabilities, induced by the exb drift of electrons in the strong lhd wave electric field. the exb wave mechanism accelerates heavy ions to energies proportional to the atomic mass number, which is consistent with satellite observations upstream of the bow shock and also with observations of post - shocks in supernovae remnants.
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arxiv:2104.00515
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molecular electronics is a new, exciting and interdisciplinary field of research. the main concern of the subject is to exploit the organic materials in electronic and optoelectronic devices. on the other hand langmuir - blodgett ( lb ) film deposition technique is one of the best among few methods used to manipulate materials in molecular level. in this article lb film preparation technique has been discussed briefly with an emphasize of its application towards molecular electronics.
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arxiv:0908.1814
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