cssi/SciSciGPT-SciSciNet huggingface dataset:
DETECTION OF ULTRAVIOLET HALOS AROUND HIGHLY INCLINED GALAXIES

We report the discovery of diffuse ultraviolet light around late-type galaxies out to 5-20 kpc from the midplane using Swift and GALEX images. The emission is consistent with the stellar outskirts in the early-type galaxies but not in the late-type galaxies, where the emission is quite blue and consistent with a reflection nebula powered by light escaping from the galaxy and scattering off dust in the halo. Our results agree with expectations from halo dust discovered in extinction by Menard et al. to within a few kpc of the disk and imply a comparable amount of hot and cold gas in galaxy halos (a few× 10{sup 8} M{sub ☉} within 20 kpc) if the dust resides primarily in Mg II absorbers. The results also highlight the potential of UV photometry to study individual galaxy halos.
Review of Magnetic Shark Deterrents: Hypothetical Mechanisms and Evidence for Selectivity

Several papers published since 2006 describe effects of magnetic fields on elasmobranchs and assess their utility in reducing negative interactions between sharks and humans, including bycatch reduction. Most of these repeat a single untested hypothesis regarding physical mechanisms by which elasmobranchs detect magnetic fields and also neglect careful consideration of magnetoreception in teleosts. Several species of teleosts are known to have magnetoreception based in biogenic magnetite, and direct magnetic field detection also has support in several species of elasmobranchs. The overly narrow focus of earlier papers on the unsupported hypothesis that magnetoreception in elasmobranchs is based in the ampullae of Lorenzini creates the impression that all teleosts will be insensitive to magnetic deterrents. However, magnetite based magnetoreception has been demonstrated in several teleosts, and is supported in others. Furthermore, electroreception is present in many teleost species; therefore, the possibility of induction based indirect magnetoreception should be considered. Finally, experiments reported as demonstrating insensitivity in teleost species to magnetic deterrents suffer from inadequate design and sample sizes to reject the hypothesis of magnetic detection in any given species. Since adoption of deterrent hook technologies depends on both deterrent effects in sharks and the absence of effects in target teleosts, the hypothesis of detection in teleost species must be independently tested with adequate sample sizes.
Uncertainties in Parameters Estimated with Neural Networks: Application to Strong Gravitational Lensing

In Hezaveh et al. we showed that deep learning can be used for model parameter estimation and trained convolutional neural networks to determine the parameters of strong gravitational-lensing systems. Here we demonstrate a method for obtaining the uncertainties of these parameters. We review the framework of variational inference to obtain approximate posteriors of Bayesian neural networks and apply it to a network trained to estimate the parameters of the Singular Isothermal Ellipsoid plus external shear and total flux magnification. We show that the method can capture the uncertainties due to different levels of noise in the input data, as well as training and architecture-related errors made by the network. To evaluate the accuracy of the resulting uncertainties, we calculate the coverage probabilities of marginalized distributions for each lensing parameter. By tuning a single variational parameter, the dropout rate, we obtain coverage probabilities approximately equal to the confidence levels for which they were calculated, resulting in accurate and precise uncertainty estimates. Our results suggest that the application of approximate Bayesian neural networks to astrophysical modeling problems can be a fast alternative to Monte Carlo Markov Chains, allowing orders of magnitude improvement in speed.
Diamagnetic drift effects on the low-n magnetohydrodynamic modes at the high mode pedestal with plasma rotation

The diamagnetic drift effects on the low-n magnetohydrodynamic instabilities at the high-mode (H-mode) pedestal are investigated in this paper with the inclusion of bootstrap current for equilibrium and rotation effects for stability, where n is the toroidal mode number. The AEGIS (Adaptive EiGenfunction Independent Solutions) code [L. J. Zheng and M. T. Kotschenreuther, J. Comp. Phys. 211 (2006)] is extended to include the diamagnetic drift effects. This can be viewed as the lowest order approximation of the finite Larmor radius effects in consideration of the pressure gradient steepness at the pedestal. The H-mode discharges at Jointed European Torus is reconstructed numerically using the VMEC code [P. Hirshman and J. C. Whitson, Phys. Fluids 26, 3553 (1983)], with bootstrap current taken into account. Generally speaking, the diamagnetic drift effects are stabilizing. Our results show that the effectiveness of diamagnetic stabilization depends sensitively on the safe factor value (qs) at the safety-fact...
Automatic extraction of road intersection points from USGS historical map series using deep convolutional neural networks

Road intersection data have been used across a range of geospatial analyses. However, many datasets dating from before the advent of GIS are only available as historical printed maps. To be analyze...
Gradient-based estimation of uncertain parameters for elliptic partial differential equations

This paper discusses the estimation of uncertain distributed diffusion coefficients in elliptic systems based on noisy measurements of the model output. We treat the parameter identification problem as a variational problem over the appropriate stochastic Sobolev spaces and show that minimizers exist and satisfy a saddle point condition. Although a lack of regularity precludes the direct use of gradient-based optimization techniques, a spectral approximation of the observation field allows us to estimate the original problem by a smooth, albeit high dimensional, deterministic optimization problem, the so-called finite noise problem, which lends itself readily to more traditional optimization approaches. We prove that the finite noise minimizers converge to the appropriate infinite dimensional ones, and devise and analyze a stochastic augmented Lagrangian method for locating these numerically. We also discuss the numerical discretization of the finite noise problem, using sparse grid hierarchical finite elements, and present three numerical examples to illustrate our method.
Stochastic Modeling of Congress

We analyze the dynamics of growth of the number of congressmen supporting the resolution HR1207 to audit the Federal Reserve. The plot of the total number of cosponsors as a function of time is of the “Devil's staircase” type. The distribution of the numbers of new cosponsors joining during a particular day (step height) follows a power law. The distribution of the length of intervals between additions of new cosponsors (step length) also follows a power law. We use a modification of Bak-Tang-Wiesenfeld sandpile model to simulate the dynamics of Congress and obtain good agreement with the data.
JDFTx: software for joint density-functional theory

Density-functional theory (DFT) has revolutionized computational prediction of atomic-scale properties from first principles in physics, chemistry and materials science. Continuing development of new methods is necessary for accurate predictions of new classes of materials and properties, and for connecting to nano- and mesoscale properties using coarse-grained theories. JDFTx is a fully-featured open-source electronic DFT software designed specifically to facilitate rapid development of new theories, models and algorithms. Using an algebraic formulation as an abstraction layer, compact C++11 code automatically performs well on diverse hardware including GPUs (Graphics Processing Units). This code hosts the development of joint density-functional theory (JDFT) that combines electronic DFT with classical DFT and continuum models of liquids for first-principles calculations of solvated and electrochemical systems. In addition, the modular nature of the code makes it easy to extend and interface with, facilitating the development of multi-scale toolkits that connect to ab initio calculations, e.g. photo-excited carrier dynamics combining electron and phonon calculations with electromagnetic simulations.
Universal behaviour of metal–insulator transitions in the p-SiGe system

Abstract Magnetoresistance measurements are presented for a strained p-SiGe quantum well sample where the density is varied through the B=0 metal–insulator transition. The close relationship between this transition, the high-field Hall insulator transition and the filling factor ν= 3 2 insulating state is demonstrated.
Unique opportunity to harness polarization in GaN to override the conventional power electronics figure-of-merits

Owing to the large breakdown electric field (E b ), wide bandgap semiconductors (WBGs) such as SiC, GaN, Ga 2 O 3 and diamond based power devices are the focus for next generation power switching applications. The unipolar trade-off relationship between the area specific-on resistance (R on,sp ) and breakdown voltage (BV) is often employed to compare the performance limitation among various materials. The advanced features in benchmarking power devices include conduction modulation and superjunction in devices taking advantage of bipolar conduction. To this end, the GaN material system has a unique advantage due to its prominent spontaneous and piezoelectric polarization effects in GaN, AlN, InN, Al x In y GaN alloys and flexibility in inserting appropriate heterojunctions thus dramatically broaden the device design space. For instance, Al x GaN, which has a larger bandgap, can be designed into the highest field region. Another enabling feature in the GaN material system is polarization doping or Pi-doping: by compositionally grading Al x In y GaN, both electron and hole doping can be achieved, exhibiting the ideal dopant behavior - no temperature dependence or frequency dependence! This dopant characteristics can't be taken for granted for WBGs based on the knowledge in Si. Pi-doping is an extremely powerful attribute since all wide bandgap semiconductors face the challenge of deep dopants while this ideal solution exists in GaN.
Heegaard surfaces and the distance of amalgamation

Let M1 and M2 be orientable irreducible 3–manifolds with connected boundary and suppose @M1 S @M2 . Let M be a closed 3–manifold obtained by gluing M1 to M2 along the boundary. We show that if the gluing homeomorphism is sufficiently complicated, then M is not homeomorphic to S and all small-genus Heegaard splittings of M are standard in a certain sense. In particular, g.M / D g.M1/Cg.M2/ g.@Mi/ , where g.M / denotes the Heegaard genus of M . This theorem is also true for certain manifolds with multiple boundary components.
Bilevel Optimization, Deep Learning and Fractional Laplacian Regularization with Applications in Tomography

In this work we consider a generalized bilevel optimization framework for solving inverse problems. We introduce fractional Laplacian as a regularizer to improve the reconstruction quality, and compare it with the total variation regularization. We emphasize that the key advantage of using fractional Laplacian as a regularizer is that it leads to a linear operator, as opposed to the total variation regularization which results in a nonlinear degenerate operator. Inspired by residual neural networks, to learn the optimal strength of regularization and the exponent of fractional Laplacian, we develop a dedicated bilevel optimization neural network with a variable depth for a general regularized inverse problem. We illustrate how to incorporate various regularizer choices into our proposed network. As an example, we consider tomographic reconstruction as a model problem and show an improvement in reconstruction quality, especially for limited data, via fractional Laplacian regularization. We successfully learn the regularization strength and the fractional exponent via our proposed bilevel optimization neural network. We observe that the fractional Laplacian regularization outperforms total variation regularization. This is specially encouraging, and important, in the case of limited and noisy data.
First principles study of structural, electronic and magnetic interplay in ferroelectromagnetic yttrium manganite

Abstract We present results of local spin density approximation pseudopotential calculations for the ferroelectromagnet, yttrium manganite (YMnO 3 ). The origin of the differences between ferroelectric and non-ferroelectric perovskite manganites is determined by comparing the calculated properties of yttrium manganite in its ferroelectric hexagonal and non-ferroelectric orthorhombic phases. In addition, orthorhombic YMnO 3 is compared with the prototypical non-ferroelectric manganite, lanthanum manganite. We show that, while the octahedral crystal field splitting of the cubic perovskite structure causes a centro-symmetric Jahn–Teller distortion around the Mn 3+ ion, the markedly different splitting in hexagonal perovskites creates an electronic configuration consistent with ferroelectric distortion. We explain the nature of the distortion, and show that a local magnetic moment on the Mn 3+ ion is a requirement for it to occur.
Topological complexity of n points on a tree

The topological complexity of a path-connected space $X,$ denoted $TC(X),$ can be thought of as the minimum number of continuous rules needed to describe how to move from one point in $X$ to another. The space $X$ is often interpreted as a configuration space in some real-life context. Here, we consider the case where $X$ is the space of configurations of $n$ points on a tree $\Gamma.$ We will be interested in two such configuration spaces. In the, first, denoted $C^n(\Gamma),$ the points are distinguishable, while in the second, $UC^n(\Gamma),$ the points are indistinguishable. We determine $TC(UC^n(\Gamma))$ for any tree $\Gamma$ and many values of $n,$ and consequently determine $TC(C^n(\Gamma))$ for the same values of $n$ (provided the configuration spaces are path-connected).
Configuration of the crucial set for a quadratic rational map

Let K be a complete, algebraically closed non-Archimedean valued field, and let \(\varphi (z) \in K(z)\) have degree two. We describe the crucial set of \(\varphi \) in terms of the multipliers of \(\varphi \) at the classical fixed points, and use this to show that the crucial set determines a stratification of the moduli space \(\mathcal {M}_2(K)\) related to the reduction type of \(\varphi \). We apply this to settle a special case of a conjecture of Hsia regarding the density of repelling periodic points in the classical non-Archimedean Julia set.
Opportunistic Routing in Ad Hoc Networks: How Many Relays Should There Be? What Rate Should Nodes Use?

Abstract-Opportunistic routing is a multi-hop routing scheme which allows for selection of the best immediately available relay. In blind opportunistic routing protocols, where transmitters blindly broadcast without knowledge of the surrounding nodes, two fundamental design parameters are the node transmission probability and the transmission spectral efficiency. In this paper these parameters are selected to maximize end-to-end performance, characterized by the product of transmitter density, hop distance and rate. Due to the intractability of the problem as stated, an approximation function is examined which proves reasonably accurate. Our results show how the above design parameters should be selected based on inherent system parameters such as the path loss exponent and the noise level.
Traces of singular moduli and moonshine for the Thompson group

We describe a relationship between the representation theory of the Thompson sporadic group and a weakly holomorphic modular form of weight one-half that appears in work of Borcherds and Zagier on Borcherds products and traces of singular moduli. We conjecture the existence of an infinite dimensional graded module for the Thompson group and provide evidence for our conjecture by constructing McKay–Thompson series for each conjugacy class of the Thompson group that coincide with weight one-half modular forms of higher level. We also observe a discriminant property in this moonshine for the Thompson group that is closely related to the discriminant property conjectured to exist in Umbral Moonshine.
Fine-tuning favors mixed axion/axino cold dark matter over neutralinos in the minimal supergravity model

Over almost all of minimal supergravity (mSUGRA or CMSSM) model parameter space, there is a large overabundance of neutralino cold dark matter (CDM). We find that the allowed regions of mSUGRA parameter space which match the measured abundance of CDM in the universe are highly fine-tuned. If instead we invoke the Peccei–Quinn–Weinberg–Wilczek solution to the strong CP problem, then the SUSY CDM may consist of an axion/axino admixture with an axino mass of order the MeV scale, and where mixed axion/axino or mainly axion CDM seems preferred. In this case, fine-tuning of the relic density is typically much lower, showing that axion/axino CDM ( $a\tilde{a}$ CDM) is to be preferred in the paradigm model for SUSY phenomenology. For mSUGRA with $a\tilde{a}$ CDM, quite different regions of parameter space are now DM-favored as compared to the case of neutralino DM. Thus, rather different SUSY signatures are expected at the LHC in the case of mSUGRA with $a\tilde{a}$ CDM, as compared to mSUGRA with neutralino CDM.
Jet Dynamics in Compact Object Mergers: GW170817 Likely Had a Successful Jet

We use relativistic hydrodynamic numerical calculations to study the interaction between a jet and a homologous outflow produced dynamically during binary neutron star mergers. We quantify how the thermal energy imparted by the jet and the ability of the jet to escape the ejecta depend on the parameters of the jet engine and the ejecta. Under our assumptions, a collimated jet initiated at early times compared to the engine duration, we show that successful breakout of the forward cocoon shock necessitates a jet that successfully escapes the ejecta. This is because the ejecta is expanding, and the forward shock from a failed jet stalls before it reaches the edge of the ejecta. This conclusion can be circumvented only for very energetic wide angle jets, with parameters that are uncomfortable given short-duration GRB observations. For successful jets, we find two regimes of jet breakout from the ejecta: early breakout on timescales shorter than the engine duration, and late breakout well after the engine shuts off. A late breakout can explain the observed delay between gravitational waves and gamma rays in GW170817. We show that for the entire parameter space of jet parameters surveyed here (covering energies ~1048–1051 erg and opening angles θ j ~ 0.07–0.4) the thermal energy deposited by the jet is less than that produced by r-process heating on second timescales by at least an order of magnitude. Shock heating is thus energetically subdominant in setting the luminosity of thermally powered transients coincident with neutron star mergers (kilonovae).
Permutative categories, multicategories and algebraic K -theory

We show that the K–theory construction of our paper [Adv. Math 205 (2006) 163-228], which preserves multiplicative structure, extends to a symmetric monoidal closed bicomplete source category, with the multiplicative structure still preserved. The source category of [op cit], whose objects are permutative categories, maps fully and faithfully to the new source category, whose objects are (based) multicategories.
Onion-peeling inversion of stellarator images

An onion-peeling technique is developed for inferring the emissivity profile of a stellarator plasma from a two-dimensional image acquired through a CCD or CMOS camera. Each pixel in the image is treated as an integral of emission along a particular line-of-sight. Additionally, the flux surfaces in the plasma are partitioned into discrete layers, each of which is assumed to have uniform emissivity. If the topology of the flux surfaces is known, this construction permits the development of a system of linear equations that can be solved for the emissivity of each layer. We present initial results of this method applied to wide-angle visible images of the Columbia Neutral Torus (CNT) stellarator plasma.
Entropic Mechanics: Towards a Stochastic Description of Quantum Mechanics

We consider a stochastic process which is (a) described by a continuous-time Markov chain on only short time-scales and (b) constrained to conserve a number of hidden quantities on long time-scales. We assume that the transition matrix of the Markov chain is given and the conserved quantities are known to exist, but not explicitly given. To study the stochastic dynamics we propose to use the principle of stationary entropy production. Then the problem can be transformed into a variational problem for a suitably defined “action” and with time-dependent Lagrange multipliers. We show that the stochastic dynamics can be described by a Schrodinger equation, with Lagrange multipliers playing the role of phases, whenever (a) the transition matrix is symmetric or the detailed balance condition is satisfied, (b) the system is not too far from the equilibrium and (c) the number of the conserved quantities is large.
The parallelism motifs of genomic data analysis

Genomic datasets are growing dramatically as the cost of sequencing continues to decline and small sequencing devices become available. Enormous community databases store and share these data with the research community, but some of these genomic data analysis problems require large-scale computational platforms to meet both the memory and computational requirements. These applications differ from scientific simulations that dominate the workload on high-end parallel systems today and place different requirements on programming support, software libraries and parallel architectural design. For example, they involve irregular communication patterns such as asynchronous updates to shared data structures. We consider several problems in high-performance genomics analysis, including alignment, profiling, clustering and assembly for both single genomes and metagenomes. We identify some of the common computational patterns or 'motifs' that help inform parallelization strategies and compare our motifs to some of the established lists, arguing that at least two key patterns, sorting and hashing, are missing. This article is part of a discussion meeting issue 'Numerical algorithms for high-performance computational science'.
Section extension from hyperbolic geometry of punctured disk and holomorphic family of flat bundles

The construction of sections of bundles with prescribed jet values plays a fundamental role in problems of algebraic and complex geometry. When the jet values are prescribed on a positive dimensional subvariety, it is handled by theorems of Ohsawa-Takegoshi type which give extension of line bundle valued square-integrable top-degree holomorphic forms from the fiber at the origin of a family of complex manifolds over the open unit 1-disk when the curvature of the metric of line bundle is semipositive. We prove here an extension result when the curvature of the line bundle is only semipositive on each fiber with negativity on the total space assumed bounded from below and the connection of the metric locally bounded, if a square-integrable extension is known to be possible over a double point at the origin. It is a Hensel-lemma-type result analogous to Artin’s application of the generalized implicit function theorem to the theory of obstruction in deformation theory. The motivation is the need in the abundance conjecture to construct pluricanonical sections from flatly twisted pluricanonical sections. We also give here a new approach to the original theorem of Ohsawa-Takegoshi by using the hyperbolic geometry of the punctured open unit 1-disk to reduce the original theorem of Ohsawa-Takegoshi to a simple application of the standard method of constructing holomorphic functions by solving the $\bar \partial $ equation with cut-off functions and additional blowup weight functions.
Continuous cohomology of topological quandles

A continuous cohomology theory for topological quandles is introduced, and compared to the algebraic theories. Extensions of topological quandles are studied with respect to continuous 2-cocycles, ...
Star Formation in the Milky Way: The Infrared View

I present a brief review of the some of the most recent and active topics of star formation process in the Milky Way using mid and far infrared observations, and motivated by the research being carried out by our science group using the data gathered by the Spitzer and Herschel space telescopes. These topics include bringing together the scaling relationships found in extragalactic systems with that of the local nearby molecular clouds, the synthetic modeling of the Milky Way and estimates of its star formation rate.
Temporal and spatial turbulent spectra of MHD plasma and an observation of variance anisotropy

The nature of magnetohydrodynamic (MHD) turbulence is analyzed through both temporal and spatial magnetic fluctuation spectra. A magnetically turbulent plasma is produced in the MHD wind tunnel configuration of the Swarthmore Spheromak Experiment. The power of magnetic fluctuations is projected into directions perpendicular and parallel to a local mean field; the ratio of these quantities shows the presence of variance anisotropy which varies as a function of frequency. Comparisons among magnetic, velocity, and density spectra are also made, demonstrating that the energy of the turbulence observed is primarily seeded by magnetic fields created during plasma production. Direct spatial spectra are constructed using multi-channel diagnostics and are used to compare to frequency spectra converted to spatial scales using the Taylor hypothesis. Evidence for the observation of dissipation due to ion inertial length scale physics is also discussed, as well as the role laboratory experiments can play in understanding turbulence typically studied in space settings such as the solar wind. Finally, all turbulence results are shown to compare fairly well to a Hall-MHD simulation of the experiment.
Spin Absorption by In Situ Deposited Nanoscale Magnets on Graphene Spin Valves

Despite significant experimental and theoretical studies of spin transport in graphene, the absorption of spins by a nanomagnet deposited on the graphene is not yet well understood. This study describes an $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ measurement as an Fe island is deposited on a graphene spin valve, and proposes a mechanism to quantitatively explain the effect of the Fe thickness in terms of the absorbed spin current, including the effect of a nonmagnetic interlayer. Its findings provide an improved understanding of the flow of spin current out of a graphene-based nonlocal spin valve, as necessary for spin-transfer-torque switching.
On the Nature of the Flux Variability during an Expansion Stage of a Type I X-Ray Burst: Constraints on Neutron Star Parameters for 4U 1820–30

We investigate closely the flux profile during the burst expansion stage observed from 4U 1820-30 with the Rossi X- Ray Timing Explorer on 1997 May 2. We are able to uncover the behavior of a photospheric radius and to simulate the evolution of the neutron star (NS) accretion disk system. We argue that although the bolometric luminosity is always the Eddington value LEdd, the photon flux at the bottom of the expanded envelope can decrease during the expansion stage. In fact, at the initial moment of explosion when the bottom burning temperature is ~2 × 109 K, the bottom flux Lbot is a few times the Eddington limit, because the electron cross section is a few times less than the Thomson cross section at such high temperatures. The surplus of energy flux with respect to the Eddington, Lbot - LEdd, goes into the potential energy of the expanded envelope. As cooling of the burning zone starts the surplus decreases, and thus the envelope shrinks while the emergent photon flux stays the same, L = LEdd. At a certain moment the NS low hemisphere, previously screened by the disk, becomes visible to the observer. Consequently, the flux detected by the observer increases. We estimate the anisotropy due to geometry and find that the system should have a high inclination angle. Finally, we apply an analytical model of X-ray spectral formation in the NS atmosphere during the burst decay stage to infer the NS mass-radius relation.
Color screening in quantum chromodynamics

Abstract We review lattice studies of the color screening in the quark–gluon plasma. We put the phenomena related to the color screening into the context of similar aspects of other physical systems (electromagnetic plasma or cold nuclear matter). We discuss the onset of the color screening and its signature and significance in the QCD transition region, and elucidate at which temperature and to which extent the weak-coupling picture based on hard thermal loop expansion, potential nonrelativistic QCD, or dimensionally-reduced QCD quantitatively captures the key properties of the color screening. We discuss the different regimes pertaining to the color screening and thermal dissociation of the static quarks in depth for various spatial correlation functions that are studied on the lattice, and clarify the status of their asymptotic screening masses. We finally discuss the screening correlation functions of dynamical mesons with a wide range of flavor and spin content, and how they conform with expectations for low- and high-temperature behavior.
Obstruction criteria for modular deformation problems

For a cuspidal newform f =∑ anqn of weight k ≥ 3 and a prime λ of Q(an), the deformation problem for its associated mod λ Galois representation is unobstructed for all primes outside some finite set. Previous results gave an explicit bound on this finite set for f of squarefree level; we modify this bound and remove the squarefree hypothesis. We also show that if the λ-adic deformation problem for f is unobstructed, then f is not congruent mod λ to a newform of lower level.
Viscous Cosmology and Thermodynamics of Apparent Horizon

It is shown that the differential form of Friedmann equations of Friedman?Robertson?Walker (FRW) universe can be recast as a similar form of the first law ThdSh = dE+WdV of thermodynamics at the apparent horizon of FRW universe filled with the viscous fluid. It is also shown that by employing the general expression of temperature associated with the apparent horizon of FRW universe and assumed that the temperature Tm of the energy inside the apparent horizon is proportional to the horizon temperature Tm = bTh, we are able to show that the generalized second law of thermodynamics holds in the Einstein gravity provided .
SIMULATED PHOTOEVAPORATIVE MASS LOSS FROM HOT JUPITERS IN 3D

Ionizing stellar photons heat the upper regions of planetary atmospheres, driving atmospheric mass loss. Gas escaping from several hot, hydrogen-rich planets has been detected using UV and X-ray transmission spectroscopy. Because these planets are tidally locked, and thus asymmetrically irradiated, escaping gas is unlikely to be spherically symmetric. In this paper, we focus on the effects of asymmetric heating on local outflow structure. We use the Athena code for hydrodynamics to produce 3D simulations of hot Jupiter mass loss that jointly model wind launching and stellar heating via photoionization. Our fiducial planet is an inflated, hot Jupiter with radius and mass . We irradiate the initially neutral, atomic hydrogen atmosphere with 13.6 eV photons and compute the outflow?s ionization structure. There are clear asymmetries in the atmospheric outflow, including a neutral shadow on the planet?s nightside. Given an incident ionizing UV flux comparable to that of the Sun, we find a steady-state mass loss rate of g s?1. The total mass loss rate and the outflow substructure along the substellar ray show good agreement with earlier 1D models, for two different fluxes. Our 3D data cube can be used to generate the outflow?s extinction spectrum during transit. As a proof of concept, we find absorption of stellar Ly? at Doppler-shifted velocities of up to ?50 km s?1. Our work provides a starting point for further 3D models that can be used to predict observable signatures of hot Jupiter mass loss.
The complicated evolution of the ACIS contamination layer over the mission life of the Chandra X-ray Observatory

The Chandra X-ray Observatory (CXO) was launched almost 19 years ago and has been delivering spectacular science over the course of its mission. The Advanced CCD Imager Spectrometer (ACIS) is the prime instrument on the satellite, conducting over 90% of the observations. The CCDs operate at a temperature of -120°C and the optical blocking filter (OBF) in front of the CCDs is at a temperature of approximately −60°C. The surface of the OBF has accumulated a layer of contamination over the course of the mission, as it is the coldest surface exposed to the interior to the spacecraft. We have been characterizing the thickness, chemical composition, and spatial distribution of the contamination layer as a function of time over the mission. All three have exhibited significant changes with time. There has been a dramatic decrease in the accumulation rate of the contaminant starting in 2017. The lower accumulation rate may be due to a decrease in the deposition rate or an increase in the vaporization rate or a combination of the two. We show that the current calibration file which models the additional absorption of the contamination layer is significantly overestimating that additional absorption by using the standard model spectrum for the supernova remnant 1E 0102.2-7219 developed by the International Astronomical Consortium for High Energy Calibration (IACHEC). In addition, spectral data from the cluster of galaxies known as Abell 1795 and the Blazar Markarian 421 are used to generate a model of the absorption produced by the contamination layer. The Chandra X-ray Center (CXC) calibration team is preparing a revised calibration file that more accurately represents the complex time dependence of the accumulation rate, the spatial dependence, and the chemical composition of the contaminant. Given the rapid changes in the contamination layer over the past year, future calibration observations at a higher cadence will be necessary to more accurately monitor such changes.
HST/COS OBSERVATIONS OF IONIZED GAS ACCRETION AT THE DISK–HALO INTERFACE OF M33

We report the detection of accreting ionized gas at the disk-halo interface of the nearby galaxy M33. We analyze HST/COS absorption-line spectra of seven ultraviolet-bright stars evenly distributed across the disk of M33. We find Si IV absorption components consistently redshifted relative to the bulk M33's ISM absorption along all the sightlines. The Si IV detection indicates an enriched, disk-wide, ionized gas inflow toward the disk. This inflow is most likely multi-phase as the redshifted components can also be observed in ions with lower ionization states (e.g., S II, P II, Fe II, Si II). Kinematic modeling of the inflow is consistent with an accreting layer at the disk-halo interface of M33, which has an accretion velocity of 110$^{+15}_{-20}$ km s$^{-1}$ at a distance of 1.5$^{+1.0}_{-1.0}$ kiloparsec above the disk. The modeling indicates a total mass of $\sim3.9\times10^7$ M$_{\odot}$ for the accreting material at the disk-halo interface on the near side of the M33 disk , with an accretion rate of $\sim2.9$ M$_{\odot}$ yr$^{-1}$. The high accretion rate and the level of metal-enrichment suggest the inflow is likely to be the fall back of M33 gas from a galactic fountain and/or the gas pulled loosed during a close interaction between M31 and M33. Our study of M33 is the first to unambiguously reveal the existence of a disk-wide, ionized gas inflow beyond the Milky Way, providing a better understanding of gas accretion in the vicinity of a galaxy disk.
Prioritizing network communities

Uncovering modular structure in networks is fundamental for systems in biology, physics, and engineering. Community detection identifies candidate modules as hypotheses, which then need to be validated through experiments, such as mutagenesis in a biological laboratory. Only a few communities can typically be validated, and it is thus important to prioritize which communities to select for downstream experimentation. Here we develop CRank, a mathematically principled approach for prioritizing network communities. CRank efficiently evaluates robustness and magnitude of structural features of each community and then combines these features into the community prioritization. CRank can be used with any community detection method. It needs only information provided by the network structure and does not require any additional metadata or labels. However, when available, CRank can incorporate domain-specific information to further boost performance. Experiments on many large networks show that CRank effectively prioritizes communities, yielding a nearly 50-fold improvement in community prioritization.
On 't Hooft defects, monopole bubbling and supersymmetric quantum mechanics

We revisit the localization computation of the expectation values of ’t Hooft operators in $$ \mathcal{N} $$ = 2* SU(N) theory on ℝ3 × S1. We show that the part of the answer arising from “monopole bubbling” on ℝ3 can be understood as an equivariant integral over a Kronheimer-Nakajima moduli space of instantons on an orbifold of ℂ2. It can also be described as a Witten index of a certain supersymmetric quiver quantum mechanics with $$ \mathcal{N} $$ = (4, 4) supersymmetry. The map between the defect data and the quiver quantum mechanics is worked out for all values of N. For the SU(2) theory, we compute several examples of these line defect expectation values using the Witten index formula and confirm that the expressions agree with the formula derived by Okuda, Ito and Taki [16]. In addition, we present a Type IIB construction — involving D1-D3-NS5-branes — for monopole bubbling in $$ \mathcal{N} $$ = 2* SU(N) SYM and demonstrate how the quiver quantum mechanics arises in this brane picture.
End-to-End Physics Event Classification with CMS Open Data: Applying Image-Based Deep Learning to Detector Data for the Direct Classification of Collision Events at the LHC

This paper describes the construction of novel end-to-end image-based classifiers that directly leverage low-level simulated detector data to discriminate signal and background processes in proton–proton collision events at the Large Hadron Collider at CERN. To better understand what end-to-end classifiers are capable of learning from the data and to address a number of associated challenges, we distinguish the decay of the standard model Higgs boson into two photons from its leading background sources using high-fidelity simulated CMS Open Data. We demonstrate the ability of end-to-end classifiers to learn from the angular distribution of the photons recorded as electromagnetic showers, their intrinsic shapes, and the energy of their constituent hits, even when the underlying particles are not fully resolved, delivering a clear advantage in such cases over purely kinematics-based classifiers.
Singularities of axially symmetric time-like minimal submanifolds in Minkowski space

We prove that there does not exist global-in-time axisymmetric solutions to the time-like minimal submanifold system in Minkowski space. We further analyze the limiting geometry as the maximal time...
The love-hate relationship between the shell model and cluster models

We adopt a personal approach here reviewing several calculations over the years in which we have experienced confrontations between cluster models and the shell model. In previous cluster conferences, we have noted that cluster models go hand in hand with Skyrme-Hartree-Fock calculations in describing states which cannot easily, if at all, be handled by the shell model. These are the highly deformed (many particle-many hole) intruder states, linear chain states, etc. In the present work, we will consider several topics: the quadrupole moment of 6Li; the nonexistence of low-lying intruders in 8Be; and then jumping to the f7/2 shell, we discuss the two-faceted nature of the nuclei, which sometimes display shell-model properties and other times cluster properties.
Mass-to-light Ratios of Spatially Resolved Stellar Populations in M31

A galaxy's stellar mass-to-light ratio ($M_\star/L$) is a useful tool for converting luminosity to stellar mass ($M_\star$). However, the practical utility of $M_\star/L$ inferred from stellar population synthesis (SPS) models is limited by mismatches between the real and assumed models for star formation history (SFH) and dust geometry, both of which vary within galaxies. Here, we measure spatial variations in $M_\star/L$ and their dependence on color, star formation history, and dust across the disk of M31, using a map of $M^\mathrm{CMD}_\star$ derived from color-magnitude diagrams of resolved stars in the Panchromatic Hubble Andromeda Treasury (PHAT) survey. First, we find comparable scatter in $M_\star/L$ for the optical and mid-IR, contrary to the common idea that $M_\star/L$ is less variable in the IR. Second, we confirm that $M_\star/L$ is correlated with color for both the optical and mid-IR and report color vs. $M_\star/L$ relations (CMLRs) in M31 for filters used in the Sloan Digital Sky Survey (SDSS) and Widefield Infrared Survey Explorer (WISE). Third, we show that the CMLR residuals correlate with recent SFH, such that quiescent regions are offset to higher $M_\star/L$ than star-forming regions at a fixed color. The mid-IR CMLR, however, is not linear due to the high scatter of $M_\star/L$ in star-forming regions. Finally, we find a flatter optical CMLR than any SPS-based CMLRs in the literature. We show this is an effect of dust geometry, which is typically neglected but should be accounted for when using optical data to map $M_\star/L$.
Virtual to Real Adaptation of Pedestrian Detectors

Pedestrian detection through Computer Vision is a building block for a multitude of applications. Recently, there has been an increasing interest in convolutional neural network-based architectures to execute such a task. One of these supervised networks' critical goals is to generalize the knowledge learned during the training phase to new scenarios with different characteristics. A suitably labeled dataset is essential to achieve this purpose. The main problem is that manually annotating a dataset usually requires a lot of human effort, and it is costly. To this end, we introduce ViPeD (Virtual Pedestrian Dataset), a new synthetically generated set of images collected with the highly photo-realistic graphical engine of the video game GTA V (Grand Theft Auto V), where annotations are automatically acquired. However, when training solely on the synthetic dataset, the model experiences a Synthetic2Real domain shift leading to a performance drop when applied to real-world images. To mitigate this gap, we propose two different domain adaptation techniques suitable for the pedestrian detection task, but possibly applicable to general object detection. Experiments show that the network trained with ViPeD can generalize over unseen real-world scenarios better than the detector trained over real-world data, exploiting the variety of our synthetic dataset. Furthermore, we demonstrate that with our domain adaptation techniques, we can reduce the Synthetic2Real domain shift, making the two domains closer and obtaining a performance improvement when testing the network over the real-world images.
COSMOLOGICAL X-RAY SCATTERING FROM INTERGALACTIC DUST

High-resolution X-ray imaging offers a unique opportunity to probe the nature of dust in the z 2 universe. Dust grains 0.1-1 μm in size will scatter soft X-rays, producing a diffuse "halo" image around an X-ray point source, with a brightness of ~ few percent confined to an arcminute-sized region. We derive the formulae for scattering in a cosmological context and calculate the surface brightness of the scattering halo due to (1) an intergalactic medium (IGM) uniformly enriched (Ωd ~ 10–5) by a power-law distribution of grain sizes and (2) a damped Lyα type (N H ~ 1021 cm–2) dust screen at cosmological distances. The morphology of the surface brightness profile can distinguish between the two scenarios above, place size constraints on dusty clumps, and constrain the homogeneity of the IGM. Thus, X-ray scattering can gauge the relative contribution of the first stars, dwarf galaxies, and galactic outflows to the cosmic metallicity budget and cosmic history of dust. We show that, because the amount of intergalactic scattering is overestimated for photon energies <1 keV, the non-detection of an X-ray scattering halo by Petric et al. is consistent with "gray" intergalactic dust grains (Ω d ~ 10–5) when the data are restricted to the 1-8 keV band. We also calculate the systematic offset in magnitude, δm ~ 0.01, for such a population of graphite grains, which would affect the type of supernova survey ideal for measuring dark energy parameters within ~1% precision.
Remarks on Legendrian Self-Linking

The Thurston-Bennequin invariant provides one notion of self-linking for any homologically trivial Legendrian curve in a contact three-manifold. Here we discuss related analytic notions of self-linking for Legendrian knots in R3. Our definition is based upon reformulation of the elementary Gauss linking integral and is motivated by ideas from supersymmetric gauge theory. We recover the Thurston-Bennequin invariant as a special case.The Thurston-Bennequin invariant provides one notion of self-linking for any homologically trivial Legendrian curve in a contact three-manifold. Here we discuss related analytic notions of self-linking for Legendrian knots in R3. Our definition is based upon reformulation of the elementary Gauss linking integral and is motivated by ideas from supersymmetric gauge theory. We recover the Thurston-Bennequin invariant as a special case.
Three Lectures On Topological Phases Of Matter

These notes are based on lectures at the PSSCMP/PiTP summer school that was held at Princeton University and the Institute for Advanced Study in July, 2015. They are devoted largely to topological phases of matter that can be understood in terms of free fermions and band theory. They also contain an introduction to the fractional quantum Hall effect from the point of view of effective field theory.
On the neutrino non-detection of GRB 130427A

The recent gamma-ray burst GRB 130427A has an isotropic electromagnetic energy E iso ~ 1054 erg, suggesting an ample supply of target photons for photo-hadronic interactions, which at its low redshift of z ~ 0.34 would appear to make it a promising candidate for neutrino detection. However, the IceCube collaboration has reported a null result based on a search during the prompt emission phase. We show that this neutrino non-detection can provide valuable information about this gamma-ray burst's (GRB's) key physical parameters such as the emission radius Rd , the bulk Lorentz factor Γ, and the energy fraction converted into cosmic rays p . The results are discussed both in a model-independent way and in the specific scenarios of an internal shock (IS) model, a baryonic photospheric (BPH) model, and a magnetic photospheric (MPH) model. We find that the constraints are most stringent for the MPH model considered, but the constraints on the IS and the BPH models are fairly modest.