cssi/SciSciGPT-SciSciNet huggingface dataset:
Achieving 100,000,000 database inserts per second using Accumulo and D4M

The Apache Accumulo database is an open source relaxed consistency database that is widely used for government applications. Accumulo is designed to deliver high performance on unstructured data such as graphs of network data. This paper tests the performance of Accumulo using data from the Graph500 benchmark. The Dynamic Distributed Dimensional Data Model (D4M) software is used to implement the benchmark on a 216-node cluster running the MIT SuperCloud software stack. A peak performance of over 100,000,000 database inserts per second was achieved which is 100× larger than the highest previously published value for any other database. The performance scales linearly with the number of ingest clients, number of database servers, and data size. The performance was achieved by adapting several supercomputing techniques to this application: distributed arrays, domain decomposition, adaptive load balancing, and single-program-multiple-data programming.
Resonant Diffusion of Normal Alkanes in Zeolites: Effect of the Zeolite Structure and Alkane Molecule Vibrations

Diffusion of normal alkanes in one-dimensional zeolites is theoretically studied on the basis of the stochastic equation formalism. The calculated diffusion coefficient accounts for the vibrations of the diffusing molecule and zeolite framework, molecule-zeolite interaction, and specific structure of the zeolite. It is shown that when the interaction potential is predominantly determined by the zeolite pore structure, the diffusion coefficient varies periodically with the number of carbon atoms of the alkane molecule, a phenomenon called resonant diffusion. A criterion for observable resonance is obtained from the balance between the interaction potentials of the molecule due to the atomic and pore structures of the zeolite. It shows that the diffusion is not resonant in zeolites without pore structure, such as ZSM-12. Moreover, even in zeolites with developed pore structure no resonant dependence of the diffusion constant can be detected if the pore structure energy barriers are not at least three times higher than the atomic structure energy barriers. The role of the alkane molecule vibrations is examined as well and a surprising effect of suppression of the diffusion in comparison with the case of a rigid molecule is observed. This effect is explained with the balance between the static and dynamic interaction of the molecule and zeolite. Zeolites attract scientific attention because of their remarkable catalytic and sorption properties. They are regular porous materials with pore size in the order of several Angstroms. Because of their structure, zeolites can exhibit molecular shape selectivity to certain molecules, which is very important for many applications of practical interest 1 . An important factor for the efficiency of each process utilizing zeolites is the rate of intracrystalline mass transfer of species. For instance, chemical reactions are catalyzed in zeolites at some active centers and, therefore, are frequently diffusion controlled since the reactants have to reach these active centers first. The methods to measure the mobility of molecules in zeolites are naturally divided in two groups 2 . The first group consists of measurements of some macroscopic integral response of the system. One can mention here, for instance, the classical absorption/desorption experiments. On this method the diffusion constant is calculated by comparing the experimental absorption/ desorption curves with exact solutions of the unsteady state diffusion equation for the particular shape of zeolite grains employed 3 . The experimental curves, however, are influenced not by the diffusion process only. In fact, there are at least three consequent processes, namely, transfer of
DISCOVERY OF A ∼250 K BROWN DWARF AT 2 pc FROM THE SUN*

Through a previous analysis of multi-epoch astrometry from the Wide-field Infrared Survey Explorer (WISE), I identified WISE J085510.83–071442.5 as a new high proper motion object. By combining astrometry from WISE and the Spitzer Space Telescope, I have measured a proper motion of 8.1 ± 0.1'' yr–1 and a parallax of 0.454 ± 0.045'' ( pc) for WISE J085510.83–071442.5, giving it the third highest proper motion and the fourth largest parallax of any known star or brown dwarf. It is also the coldest known brown dwarf based on its absolute magnitude at 4.5 μm and its color in [3.6]-[4.5]. By comparing M 4.5 with the values predicted by theoretical evolutionary models, I estimate an effective temperature of 225-260 K and a mass of 3-10 M Jup for the age range of 1-10 Gyr that encompasses most nearby stars.
Inapproximability of Orthogonal Compaction

We show that several problems of compacting orthogonal graph drawings to use the minimum number of rows, area, length of longest edge or total edge length cannot be approximated better than within a polynomial factor of optimal in polynomial time unless P = NP. We also provide a fixed-parameter-tractable algorithm for testing whether a drawing can be compacted to a small number of rows. Submitted: November 2011 Reviewed: February 2012 Revised: February 2012 Accepted: February 2012 Final: March 2012 Published: September 2012 Article type: Regular paper Communicated by: M. van Kreveld and B. Speckmann This work was supported in part by NSF grant 0830403 and by the Office of Naval Research under grant N00014-08-1-1015. A previous version of this paper appeared in the International Symposium on Graph Drawing 2011. E-mail addresses: mbannist@uci.edu (Michael J. Bannister) eppstein@uci.edu (David Eppstein) jsimons@uci.edu (Joseph A. Simons) 652 Bannister, Eppstein, Simons Compaction for Graph Drawings
Asymptotically optimal, sequential, multiple testing procedures with prior information on the number of signals

Assuming that data are collected sequentially from independent streams, we consider the simultaneous testing of multiple binary hypotheses under two general setups; when the number of signals (correct alternatives) is known in advance, and when we only have a lower and an upper bound for it. In each of these setups, we propose feasible procedures that control, without any distributional assumptions, the familywise error probabilities of both type I and type II below given, user-specified levels. Then, in the case of i.i.d. observations in each stream, we show that the proposed procedures achieve the optimal expected sample size, under every possible signal configuration, asymptotically as the two error probabilities vanish at arbitrary rates. A simulation study is presented in a completely symmetric case and supports insights obtained from our asymptotic results, such as the fact that knowledge of the exact number of signals roughly halves the expected number of observations compared to the case of no prior information.
X-Ray Halos and Large Grains in the Diffuse Interstellar Medium

Recent observations with dust detectors on board the interplanetary spacecrafts Ulysses and Galileo have recorded a substantial flux of large interstellar grains with radii between 0.25 and 2.0 μm entering the solar system from the local interstellar cloud. The most commonly used interstellar grain size distribution is characterized by an a-3.5 power law in grain radii a and extends to a maximum grain radius of 0.25 μm. The extension of the interstellar grain size distribution to such large radii will have a major effect on the median grain size and on the amount of mass needed to be tied up in dust for a given visual optical depth. It is therefore important to investigate whether this population of larger dust particles prevails in the general interstellar medium or whether it is merely a local phenomenon. The presence of large interstellar grains can be inferred mainly from their effect on the intensity and radial profile of scattering halos around X-ray sources. In this Letter, we examine the grain size distribution that gives rise to the X-ray halo around Nova Cygni 1992. The results of our study confirm the need to extend the interstellar grain size distribution in the direction of this source to and possibly beyond 2 μm. The model that gives the best fit to the halo data is characterized by (1) a grain size distribution that follows an a-3.5 power law up to 0.50 μm, followed by an a-4.0 extension from 0.50 to 2.0 μm, and (2) silicate and graphite (carbon) dust-to-gas mass ratios of 0.0044 and 0.0022, respectively, consistent with solar abundance constraints. Additional observations of X-ray halos probing other spatial directions are badly needed to test the general validity of this result.
Resonant Uniqueness of Radial Semiclassical Schrödinger Operators

We prove that radial, monotonic, superexponentially decaying potentials in R^n, n greater than or equal to 1 odd, are determined by the resonances of the associated semiclassical Schrodinger operator among all superexponentially decaying potentials in R^n.
Finite-dimensional representations of W-algebras

W-algebras of finite type are certain finitely generated associative algebras closely related to the universal enveloping algebras of semisimple Lie algebras. In this paper we prove a conjecture of Premet that gives an almost complete classification of finite dimensional irreducible modules for W-algebras. Also we study a relation between Harish- Chandra bimodules and bimodules over W-algebras.
A duality principle for selection games

A dinner table seats k guests and holds n discrete morsels of food. Guests select morsels in turn until all are consumed. Each guest has a ranking of the morsels according to how much he would enjoy eating them; these rankings are commonly known. A gallant knight always prefers one food division over another if it provides strictly more enjoyable collections of food to one or more other players (without giving a less enjoyable collection to any other player), even if it makes his own collection less enjoyable. A boorish lout always selects the morsel that gives him the most enjoyment on the current turn regardless of future consumption by himself and others. We show that the way the food is divided when all guests are gallant knights is the same as when all guests are boorish louts, but turn order is reversed. This implies and generalizes a classical result of Kohler and Chandrasekaran (1971) about two players strategically maximizing their own enjoyments. We also treat the case where the table contains a mixture of boorish louts and gallant knights. Our main result can also be formulated in terms of games in which selections are made by groups. In this formulation, the surprising fact is that a group can always find a selection that is simultaneously optimal for each member of the group. Suppose that k guests are seated at a table containing n discrete morsels of food (sushi rolls, say). Each player i has a strict ranking <i of the n morsels according to how enjoyable they are to eat. Players take turns selecting and consuming a morsel from the table, according to a fixed turn order P1, P2, . . . , Pm, where m ≤ n, and Pt ∈ {1, 2, . . . , k} is the player who selects a morsel on the t th turn. Our dinner guests do not simply play to maximize their own enjoyment. Instead, each guest conforms to one of two stereotypes: he is either a gallant knight or a boorish lout, as explained below. A plate is a subset of the morsels. Each player’s ranking of the morsels determines a corresponding partial ordering on plates of a fixed size according to pairwise comparison: Given two plates A and A′ of the same size, write A ≤i A′ if there is a bijection f : A → A′ such that a ≤i f(a) for all a ∈ A. Received by the editors October 21, 2011 and, in revised form, February 14, 2012. 2010 Mathematics Subject Classification. Primary 91A10, 91A18, 91A06, 91A50.
Spin-photon entanglement interfaces in silicon carbide defect centers

Optically active spins in solid-state systems can be engineered to emit photons that are entangled with the spin in the solid. This allows for applications such as quantum communications, quantum key distribution, and distributed quantum computing. Recently, there has been a strong interest in silicon carbide defects, as they emit very close to the telecommunication wavelength, making them excellent candidates for long range quantum communications. In this work we develop explicit schemes for spin-photon entanglement in several SiC defects: the silicon monovacancy, the silicon divacancy, and the NV center in SiC. Distinct approaches are given for (i) single-photon and spin entanglement and (ii) the generation of long strings of entangled photons. The latter are known as cluster states and comprise a resource for measurement-based quantum information processing.
XTE J2123–058: A New Neutron Star X-Ray Transient

We report on optical and RXTE observations of a new high-latitude bursting X-ray transient, XTE J2123-058. We identified the optical counterpart and discovered a 5.9573 ± 0.0016 hr periodic optical modulation, which was subsequently shown to be the same as the spectroscopic orbital period. From the absence of orbital X-ray modulation and the presence of partial optical eclipses we conclude that the binary inclination is between 55° and 73°. From the optical magnitude in quiescence and from the X-ray flux of type I X-ray bursts, we estimate that the source distance is between 4.5 and 15 kpc, which implies that the source is unusually far from the Galactic plane, since b = -362. Optical bursts with properties consistent with being reprocessed X-ray bursts occurred. We detected a pair of high-frequency quasi-periodic oscillations (QPOs) at 847.1 ± 5.5 Hz and 1102 ± 13 Hz simultaneously. According to the beat-frequency model, this QPO separation implies a neutron star spin period of 3.92 ± 0.22 ms. A change in the energy spectrum occurred during the decay of the outburst, which may have been due to the onset of the propeller mechanism. If so, then the neutron star magnetic field strength is between 2 and 8 × 108 G for an assumed distance of 10 kpc. However, the changes in the timing and spectral properties observed during the decay are typical of atoll sources, which may indicate that the changes are due solely to the dynamics of the accretion disk. As the phase-averaged V-band magnitude declined from 17.26 at the peak of the outburst to 19.24, and the X-ray flux decreased from 9.6 × 10-10 to 7.3 × 10-11 ergs cm-2 s-1, the peak-to-peak amplitude of the V-band modulation increased from 0.75 to 1.49 mag. This behavior can be explained if the size of the accretion disk decreases during the decay of the outburst.
Nonlinear Behavior of Baryon Acoustic Oscillations in Redshift Space from the Zel'dovich Approximation

Baryon acoustic oscillations (BAO) are a powerful probe of the expansion history of the universe, which can tell us about the nature of dark energy. In order to accurately characterize the dark energy equation of state using BAO, we must understand the effects of both nonlinearities and redshift space distortions on the location and shape of the acoustic peak. In a previous paper, we introduced a novel approach to second order perturbation theory in configuration space using the Zel'dovich approximation, and presented a simple result for the first nonlinear term of the correlation function. In this paper, we extend this approach to redshift space. We show how to perform the computation and present the analytic result for the first nonlinear term in the correlation function. Finally, we validate our result through comparison with numerical simulations.
Skew Calabi-Yau triangulated categories and Frobenius Ext-algebras

Author(s): Reyes, M; Rogalski, D; Zhang, JJ | Abstract: We investigate conditions that are sufficient to make the Extalgebra of an object in a (triangulated) category into a Frobenius algebra, and compute the corresponding Nakayama automorphism. As an application, we prove the conjecture that hdet(μA) = 1 for any noetherian Artin-Schelter regular (hence skew Calabi-Yau) algebra A.
Developing peer instruction questions for quantitative problems for an upper-division astronomy course

Decades of research show that students learn more in classes that utilize active learning than they do in traditional, lecture-only classes. Active learning also reduces the achievement gaps that are often present between various demographic groups. Given these well-established results, instructors of upper-division astronomy courses may decide to search the astronomy education research literature in hopes of finding some guidance on common student difficulties, as well as research-validated and research-based active learning curricula. Their search will be in vain. The current literature on upper-division astronomy is essentially non-existent. This is a shame, since many upper-division astronomy students will experience conceptual and problem-solving difficulties with the quantitative problems they encounter. These difficulties may exist even if students have a strong background in mathematics. In this paper, I examine one quantitative problem that is representative of those that upper-division astronomy students are expected to solve. I list many of the subtle pieces of information that students need to understand in order to advance toward a solution and I describe how such a list can be used to generate Peer Instruction (PI) questions. I also provide guidelines for instructors who wish to develop and implement their own PI questions. These PI questions can be used to increase the amount of active learning that occurs in an upper-division astronomy course. They help develop students' understandings of symbolic, mathematical representations, and they help improve students' problem-solving skills. The ideas presented in this paper can help instructors infuse their upper-division astronomy courses with active learning.
Presentation of affine Kac–Moody groups over rings

Tits has defined Steinberg groups and Kac-Moody groups for any root system and any commutative ring R. We establish a Curtis-Tits-style presentation for the Steinberg group St of any rank ≥ 3 irreducible affine root system, for any R. Namely, St is the direct limit of the Steinberg groups coming from the 1and 2-node subdiagrams of the Dynkin diagram. This leads to a completely explicit presentation. Using this we show that St is finitely presented if the rank is ≥ 4 and R is finitely generated as a ring, or if the rank is 3 and R is finitely generated as a module over a subring generated by finitely many units. Similar results hold for the corresponding Kac-Moody groups when R is a Dedekind domain of arithmetic type.
Nanofiber-segment ring resonator

We describe a fiber ring resonator comprised of a relatively long loop of standard single-mode fiber with a short nanofiber segment. The evanescent mode of the nanofiber segment allows the cavity-enhanced field to interact with atoms in close proximity to the nanofiber surface. We report on an experiment using a warm atomic vapor and low-finesse cavity, and briefly discuss the potential for reaching the strong coupling regime of cavity QED by using trapped atoms and a high-finesse cavity of this kind.
Neutron rich matter in the laboratory and in the heavens after GW170817

Abstract The historic observations of the neutron star merger GW170817 advanced our understanding of r-process nucleosynthesis and the equation of state (EOS) of neutron rich matter. Simple neutrino physics suggests that supernovae are not the site of the main r-process. Instead, the very red color of the kilonova associated with GW170817 shows that neutron star (NS) mergers are an important r-process site. We now need to measure the masses and beta decay half-lives of very neutron rich heavy nuclei so that we can more accurately predict the abundances of heavy elements that are produced. This can be done with new radioactive beam accelerators such as the Facility for Rare Isotope Beams (FRIB). GW170817 provided information on the deformability of NS and the equation of state of dense matter. The PREX II experiment will measure the neutron skin of 208 Pb and help constrain the low density EOS. As the sensitivity of gravitational wave detectors improve, we expect to observe many more events. We look forward to exciting advances and surprises!
D-brane decay in two-dimensional string theory

We consider unstable D0-branes of two dimensional string theory, described by the boundary state of Zamolodchikov and Zamolodchikov [36] multiplied by the Neumann boundary state for the time coordinate t. In the dual description in terms of the c = 1 matrix model, this D0-brane is described by a matrix eigenvalue on top of the upside down harmonic oscillator potential. As suggested by McGreevy and Verlinde [25], an eigenvalue rolling down the potential describes D-brane decay. As the eigenvalue moves down the potential to the asymptotic region it can be described as a free relativistic fermion. Bosonizing this fermion we get a description of the state in terms of a coherent state of the tachyon field in the asymptotic region, up to a non-local linear field redefinition by an energy-dependent phase. This coherent state agrees with the exponential of the closed string one-point function on a disk with Sen's marginal boundary interaction for t which describes D0-brane decay.
Effective String Theory Revisited

We revisit the effective field theory of long relativistic strings such as confining flux tubes in QCD. We derive the Polchinski-Strominger interaction by a calculation in static gauge. This interaction implies that a non-critical string which initially oscillates in one direction gets excited in orthogonal directions as well. In static gauge no additional term in the effective action is needed to obtain this effect. It results from a one-loop calculation using the Nambu-Goto action. Non-linearly realized Lorentz symmetry is manifest at all stages in dimensional regularization. We also explain that independent of the number of dimensions non-covariant counterterms have to be added to the action in the commonly used zeta-function regularization.
Nanoscale strain engineering of giant pseudo-magnetic fields, valley polarization, and topological channels in graphene

The existence of nontrivial Berry phases associated with two inequivalent valleys in graphene provides interesting opportunities for investigating the valley-projected topological states. Examples of such studies include observation of anomalous quantum Hall effect in monolayer graphene, demonstration of topological zero modes in “molecular graphene” assembled by scanning tunneling microscopy, and detection of topological valley transport either in graphene superlattices or at bilayer graphene domain walls. However, all aforementioned experiments involved nonscalable approaches of either mechanically exfoliated flakes or atom-by-atom constructions. Here, we report an approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering at room temperature. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields (up to ~800 T), valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene, thus paving a pathway toward scalable graphene-based valleytronics.
Replica wormhole and information retrieval in the SYK model coupled to Majorana chains

Motivated by recent studies of the information paradox in (1+1)-D anti-de Sitter spacetime with a bath described by a (1+1)-D conformal field theory, we study the dynamics of second Ŕenyi entropy of the Sachdev-Ye-Kitaev (SYK) model (χ) coupled to a Majorana chain bath (ψ). The system is prepared in the thermofield double (TFD) state and then evolved by HL + HR. For small system-bath coupling, we find that the second Renyi entropy $$ {S}_{\upchi L,\upchi R}^{(2)} $$ of the SYK model undergoes a first order transition during the evolution. In the sense of holographic duality, the long-time solution corresponds to a “replica wormhole”. The transition time corresponds to the Page time of a black hole coupled to a thermal bath. We further study the information scrambling and retrieval by introducing a classical control bit, which controls whether or not we add a perturbation in the SYK system. The mutual information between the bath and the control bit shows a positive jump at the Page time, indicating that the entanglement wedge of the bath includes an island in the holographic bulk.
A Unified Interpretation of Stress in Molecular Systems

The microscopic definition for the Cauchy stress tensor has been examined in the past from many different perspectives. This has led to different expressions for the stress tensor and consequently the “correct” definition has been a subject of debate and controversy. In this work, a unified framework is set up in which all existing definitions can be derived, thus establishing the connections between them. The framework is based on the non-equilibrium statistical mechanics procedure introduced by Irving, Kirkwood and Noll, followed by spatial averaging. The Irving–Kirkwood–Noll procedure is extended to multi-body potentials with continuously differentiable extensions and generalized to non-straight bonds, which may be important for particles with internal structure. Connections between this approach and the direct spatial averaging approach of Murdoch and Hardy are discussed and the Murdoch–Hardy procedure is systematized. Possible sources of non-uniqueness of the stress tensor, resulting separately from both procedures, are identified and addressed. Numerical experiments using molecular dynamics and lattice statics are conducted to examine the behavior of the resulting stress definitions including their convergence with the spatial averaging domain size and their symmetry properties.
Toward a spectral theory of cellular sheaves

This paper outlines a program in what one might call spectral sheaf theory—an extension of spectral graph theory to cellular sheaves. By lifting the combinatorial graph Laplacian to the Hodge Laplacian on a cellular sheaf of vector spaces over a regular cell complex, one can relate spectral data to the sheaf cohomology and cell structure in a manner reminiscent of spectral graph theory. This work gives an exploratory introduction, and includes discussion of eigenvalue interlacing, sparsification, effective resistance, synchronization, and sheaf approximation. These results and subsequent applications are prefaced by an introduction to cellular sheaves and Laplacians.
Resource allocation with population dynamics

We study the problem of provisioning of information about the state of a system of shared resources to its users, assuming the state of the system is a result of the actions of the users and that the information about the state, in turn, drive the actions of the users. We extend the formulation of Marecek et al. [Int. J. Control 88(10), 2015], such that the evolution of a heterogeneous population of users is governed by a Markov chain. Still, we are able to show that the distribution of users across the resources converges in distribution, for suitable means of provisioning the information about the system, under certain assumptions. The model and proof techniques may have wider applicability.
Hamiltonian formulation of open WZW strings

Using a Hamiltonian approach, we construct the classical and quantum theory of open WZW strings on a strip. (These are the strings which end on WZW branes.) The development involves non-Abelian generalized Dirichlet images in an essential way. At the classical level, we find a new non-commutative geometry in which the equal-time coordinate brackets are non-zero at the world-sheet boundary, and the result is an intrinsically non-Abelian effect which vanishes in the Abelian limit. Using the classical theory as a guide to the quantum theory, we also find the operator algebra and the analogue of the Knizhnik–Zamolodchikov equations for the conformal field theory of open WZW strings.
Detection of Highly Ionized Metal Absorption Lines in the Ultracompact X-Ray Dipper 4U 1916–05

We present the high-resolution Chandra X-Ray Observatory persistent (nondip) spectrum of 4U 1916-05, which revealed narrow absorption lines from hydrogenic neon, magnesium, silicon, and sulfur, in addition to the previous identified hydrogenic and helium-like iron absorption lines. This makes 4U 1916-05 only the second of the classical X-ray dipper systems to show narrow absorption lines from elements other than iron. We propose two possible explanations for the small measured line widths (500-2000 km s-1), compared to the expected Keplerian velocities (>1000 km s-1) of the accretion disk in this 50 minute orbital period system, and lack of wavelength shifts (250 km s-1). First, the ionized absorber may be stationary. Alternatively, the line properties may measure the relative size of the emission region. From this hypothesis, we find that the emission region is constrained to be 0.25 times the radial extent of the absorber. Our results also imply that the ionized absorber spans a range of ionization parameters.
Sensitivity of 8B breakup cross section to projectile structure in CDCC calculations

Given the astrophysical interest of 7Be(p, γ)8B, there have been several experiments applying the Coulomb dissociation method for extracting the capture rate. Measurements at Michigan State are dominated by E1 contributions but have a small E2 component. On the other hand, a lower energy measurement at Notre Dame has a much stronger E2 contribution. The expectation was that the two measurements would tie down the E2 and thus allow for an accurate extraction of the E1 relevant for the capture process. The aim of this paper is to show that the E2 factor in breakup reactions does not translate into a scaling of the E2 contribution in the corresponding capture reaction. We show that changes to the 8B single particle parameters, which are directly related to the E2 component in the capture reaction, do not affect the corresponding breakup reactions, using the present reaction theory.
Provable approximation properties for deep neural networks

Abstract We discuss approximation of functions using deep neural nets. Given a function f on a d-dimensional manifold Γ ⊂ R m , we construct a sparsely-connected depth-4 neural network and bound its error in approximating f. The size of the network depends on dimension and curvature of the manifold Γ, the complexity of f, in terms of its wavelet description, and only weakly on the ambient dimension m. Essentially, our network computes wavelet functions, which are computed from Rectified Linear Units (ReLU).
Time Dependence of the Mass Accretion Rate in Cluster Cooling Flows

We analyze two time-dependent cluster cooling flow models in spherical symmetry. The first assumes that the intracluster gas resides in a static external potential and includes the effects of optically thin radiative cooling and mass deposition. This corresponds to previous steady state cooling flow models calculated by White & Sarazin in 1987. Detailed agreement is found between steady state models and time-dependent models at fixed times in the simulations. The mass accretion rate is found either to increase or to remain nearly constant once flows reach a steady state. The time rate of change of is strongly sensitive to the value of the mass deposition parameter q but only mildly sensitive to the ratio β of gravitational binding energy to gas temperature. We show that previous scaling arguments presented by Bertschinger in 1988 and by White in the same year are valid only for mature cooling flows with weak mass deposition (q 1). The second set of models includes the effects of a secularly deepening cluster potential and secondary infall of gas from the Hubble flow. We find that such heating effects do not prevent the flows from reaching a steady state within an initial central cooling time.
Emergent spacetime & Quantum Entanglement in Matrix theory

In the context of the Bank-Fishler-Shenker-Susskind Matrix theory, we analyze a spherical membrane in light-cone M theory along with two asymptotically distant probes. In the appropriate energy regime, we find that the membrane behaves like a smeared Matrix black hole; and the spacetime geometry seen by the probes can become non-commutative even far away from regions of Planckian curvature. This arises from non-linear Matrix interactions where fast matrix modes lift a flat direction in the potential — akin to the Paul trap phenomenon in atomic physics. In the regime where we do have a notion of emergent spacetime, we show that there is non-zero entanglement entropy between supergravity modes on the membrane and the probes. The computation can easily be generalized to other settings, and this can help develop a dictionary between entanglement entropy and local geometry — similar to Ryu-Takayanagi but instead for asymptotically flat backgrounds.
Keyframe-based Direct Thermal–Inertial Odometry

This paper proposes an approach for fusing direct radiometric data from a thermal camera with inertial measurements to extend the robotic capabilities of aerial robots for navigation in GPS–denied and visually degraded environments in the conditions of darkness and in the presence of airborne obscurants such as dust, fog and smoke. An optimization based approach is developed that jointly minimizes the re–projection error of 3D landmarks and inertial measurement errors. The developed solution is extensively verified against both ground– truth in an indoor laboratory setting, as well as inside an underground mine under severely visually degraded conditions.
Modeling Cosmic Expansion, and Possible Inflation, as a Thermodynamic Heat Engine

If we assume a closed universe with slight positive curvature, cosmic expansion can modeled as a heat engine where we define the “system”, collectively, as those regions of space within the observable universe, which will later evolve into voids/ empty space. We identify the “surroundings”, collectively, as those pockets of space, which will eventually develop into matter-filled galaxies, clusters, super-clusters and filament walls. Using this model, we can find the energy needed for cosmic expansion using basic thermodynamic principles, and prove that cosmic expansion had as its origin, a finite initial energy density, pressure, volume, and temperature. Inflation in the traditional sense, with the inflaton field, may also not be required. We will argue that homogeneities and in-homogeneities in the WMAP temperature profile is attributable to quantum mechanical fluctuations about a fixed background temperature in the initial isothermal expansion phase. Fluctuations in temperature can cause certain regions of space to lose heat. Other regions will absorb that heat. The voids are those regions which absorb the heat forcing, i.e., fueling expansion of the latter and creating slightly cooler temperatures in the former, where matter will later congregate. Upon freeze-out, 2 this could produce the observed WMAP signature with its associated CBR fluctuation in magnitude. Finally, we estimate that the freeze-out temperature and the freeze-out time for WMAP in-homogeneities, occurred at roughly 3.02 * 1027 K and 2.54 * 10-35 s, respectively, after first initiation of volume expansion. This is in line with current estimates for the end of the inflationary epoch. The heat input in the inflationary phase is estimated to be Q = 1.81 * 1094 J, and the void volume increases by a factor of only 5.65. The bubble voids in the observable universe increase, collectively, in size from about .046 m3 to .262 m3 within this inflationary period.
A numerical simulation of a plunging breaking wave

ONR Program Manager: Dr. Patrick Purtell. ONR Contract Number: N00014-07-C-0184. Computer resources provided by the DoD High Performance Computing Modernization Program at the ERDC DoD Supercomputing Research Center, Vicksburg MS.
Anomalous Refraction of Space-time Wave Packets

We formulate and confirm experimentally a new law of refraction for wave packets endowed with judicious spatio-temporal correlations, which reveals an anomalous-refraction regime: the pulse speeds up when traveling from low-index to high-index non-dispersive media.
High-throughput digitization of analog human echocardiography data

Echocardiographic imaging has been acquired in historical longitudinal cohorts of cardiovascular disease. Many cohorts were established prior to digital recording of echocardiography, and thus have preserved their archival imaging on Video Home System (VHS) tapes. These tapes require large physical storage space, are affected by physical degradation, and cannot be analyzed using modern digital techniques. We have designed and implemented a standardized methodology for digitizing analog data in historical longitudinal cohorts. The methodology creates a pipeline through critical steps of initial review, digitization, anonymization, quality control, and storage. The methodology has been implemented in the Framingham Offspring Study, a community-based epidemiological cohort study with echocardiography performed during serial examinations between 1987 and 1998. We present this method as an accessible pipeline for preserving and repurposing historical imaging data acquired from large cohort studies. The described technique:•Outlines a generalizable pipeline for digitization of analog recordings of echocardiography stored on VHS tapes•Addresses research concerns including quality control, anonymization, and storage•Expresses the authors' individual experience regarding observed image quality, training needs, and potential limitations to help readers understand the costs and benefits of this method.
Information Technology, Business Strategy and the Reassignment of Work from In‐House Employees to Agency Temps†

Though we now understand how information technology (IT) influences work, we know much less about how it reshapes the actual relationship between workers and their employers. That is, to what extent do employers deploy new technologies towards the erosion of traditional employment relationships? This study relies on a cross section of British workplaces to provide statistical evidence that IT actually facilitates managers’ reassignment of work once done by in‐house employees to those working instead for a staffing agency, an effect that trebles in magnitude where managers have simultaneously cut employment. Furthermore, IT differentially serves opposing business strategies. While employers electing to compete on price rather than quality are more likely to reassign work, managers enacting quality‐centred strategies are more likely to rely on IT to avert work reassignment. The findings demonstrate that new technologies may facilitate this form of externalization, but they do not unilaterally drive it. The estimates also illuminate IT's indirect impact on workers via managers’ use of it as a tool for restructuring employment.
Speech Recognition: Transcription and Transformation of Human Speech

The specified subfield of computational linguistics and computer science can said to be linked with speech recognition. Speech recognition can develop new variation technologies as well as methodologies generated as interdisciplinary concept. It can be considered to translate and recognize and satisfy the capability towards understanding and translating the words that are already spoken. It is more preciously said that in the most recent times this field has secured positive feedback by intense learning of voice recognition. Such evidences shows the proof that it has more market demand for implementing the application of specific data as voice recognition. Deployment of speech recognition systems can be utilized as the evidence shown to its analyzing methods that is helpful for designing each and every individual’s future. It is said that the computer plays an important role for this process as by this all the translated words can be acknowledged by the texts also.
Representations of principal W-algebra for the superalgebra Q(n) and the super Yangian YQ(1)

Abstract We classify irreducible representations of finite W-algebra for the queer Lie superalgebra Q ( n ) associated with the principal nilpotent coadjoint orbits. We use this classification and our previous results to obtain a classification of irreducible finite-dimensional representations of the super Yangian Y Q ( 1 ) .
Single T gate in a Clifford circuit drives transition to universal entanglement spectrum statistics

Clifford circuits are insufficient for universal quantum computation or creating $t$-designs with $t\ge 4$. While the entanglement entropy is not a telltale of this insufficiency, the entanglement spectrum is: the entanglement levels are Poisson-distributed for circuits restricted to the Clifford gate-set, while the levels follow Wigner-Dyson statistics when universal gates are used. In this paper we show, using finite-size scaling analysis of different measures of level spacing statistics, that in the thermodynamic limit, inserting a single T $(\pi/8)$ gate in the middle of a random Clifford circuit is sufficient to alter the entanglement spectrum from a Poisson to a Wigner-Dyson distribution.
Distributions of distances and volumes of balls in homogeneous lens spaces

Abstract Lens spaces are a family of manifolds that have been a source of many interesting phenomena in topology and differential geometry. Their concrete construction, as quotients of odd-dimensional spheres by a free linear action of a finite cyclic group, allows a deeper analysis of their structure. In this paper, we consider the problem of moments for the distance function between randomly selected pairs of points on homogeneous three-dimensional lens spaces. We give a derivation of a recursion relation for the moments, a formula for the kth moment, and a formula for the moment generating function, as well as an explicit formula for the volume of balls of all radii in these lens spaces.
Governance by Other Means: Rankings as Regulatory Systems

This article takes the challenges of global governance and legitimacy seriously and looks at new ways in which international organizations (IOs) have attempted to ‘govern’ without explicit legal or regulatory directives. Specifically, we explore the growth of global performance indicators as a form of social control that appears to have certain advantages even as states and civil society actors push back against international regulatory authority. This article discusses the ways in which Michael Zurn's diagnosis of governance dilemmas helps to explain the rise of such ranking systems. These play into favored paradigms that give information and market performance greater social acceptance than rules, laws, and directives designed by international organizations. We discuss how and why these schemes can constitute governance systems, and some of the evidence regarding their effects on actors’ behaviors. Zurn's book provides a useful context for understanding the rise and effectiveness of Governance by Other Means: systems that ‘inform’ and provoke competition among states, shaping outcomes without directly legislating performance.
Synthesis of lossless electric circuits based on prescribed Jordan forms

We advance here an algorithm of the synthesis of lossless electric circuits such that their evolution matrices have the prescribed Jordan canonical forms subject to natural constraints. Every synthesized circuit consists of a chain-like sequence of LC-loops coupled by gyrators. All involved capacitances, inductances, and gyrator resistances are either positive or negative with values determined by explicit formulas. A circuit must have at least one negative capacitance or inductance for having a nontrivial Jordan block for the relevant matrix.
Simplifying dependent reductions in the polyhedral model

A Reduction – an accumulation over a set of values, using an associative and commutative operator – is a common computation in many numerical computations, including scientific computations, machine learning, computer vision, and financial analytics. Contemporary polyhedral-based compilation techniques make it possible to optimize reductions, such as prefix sums, in which each component of the reduction’s output potentially shares computation with another component in the reduction. Therefore an optimizing compiler can identify the computation shared between multiple components and generate code that computes the shared computation only once. These techniques, however, do not support reductions that – when phrased in the language of the polyhedral model – span multiple dependent statements. In such cases, existing approaches can generate incorrect code that violates the data dependences of the original, unoptimized program. In this work, we identify and formalize the optimization of dependent reductions as an integer bilinear program. We present a heuristic optimization algorithm that uses an affine sequential schedule of the program to determine how to simplfy reductions yet still preserve the program’s dependences. We demonstrate that the algorithm provides optimal complexity for a set of benchmark programs from the literature on probabilistic inference algorithms, whose performance critically relies on simplifying these reductions. The complexities for 10 of the 11 programs improve siginifcantly by factors at least of the sizes of the input data, which are in the range of 104 to 106 for typical real application inputs. We also confirm the significance of the improvement by showing speedups in wall-clock time that range from 1.1x to over 106x.
Resist: Reconstruction of irises from templates

Iris recognition systems transform an iris image into a feature vector. The seminal pipeline segments an image into iris and non-iris pixels, normalizes this region into a fixed-dimension rectangle, and extracts features which are stored and called a template (Daugman, 2009). This template is stored on a system. A future reading of an iris can be transformed and compared against template vectors to determine or verify the identity of an individual. As templates are often stored together, they are a valuable target to an attacker. We show how to invert templates across a variety of iris recognition systems. Our inversion is based on a convolutional neural network architecture we call RESIST (REconStructing IriSes from Templates). We apply RESIST to a traditional Gabor filter pipeline, to a DenseNet (Huang et al., CVPR 2017)feature extractor, and to a DenseNet architecture that works without normalization. Both DenseNet feature extractors are based on the recent ThirdEye recognition system (Ahmad and Fuller, BTAS 2019). When training and testing using the ND-0405 dataset, reconstructed images demonstrate a rank-1 accuracy of 100%, 76%, and 96% respectively for the three pipelines. The core of our approach is similar to an autoencoder. To obtain high accuracy this core is integrated into an adversarial network (Goodfellow et al., NeurIPS, 2014)