cssi/SciSciGPT-SciSciNet huggingface dataset:
The SPOTS Models: A Grid of Theoretical Stellar Evolution Tracks and Isochrones for Testing the Effects of Starspots on Structure and Colors

One-dimensional stellar evolution models have been successful at representing the structure and evolution of stars in diverse astrophysical contexts, but complications have been noted in the context of young, magnetically active stars, as well as close binary stars with significant tidal interactions. Numerous puzzles are associated with pre-main sequence and active main-sequence stars, relating to their radii, their colors, certain elemental abundances, and the coevality of young clusters, among others. A promising explanation for these puzzles is the distorting effects of magnetic activity and starspots on the structure of active stars. To assist the community in evaluating this hypothesis, we present the Stellar Parameters Of Tracks with Starspots (SPOTS) models, a grid of solar-metallicity stellar evolutionary tracks and isochrones which include a treatment of the structural effects of starspots. The models range from 0.1-1.3\msun and from spot-less to a surface covering fraction of 85\%, and are evolved from the pre-main sequence to the red giant branch (or 15~Gyr). We also produce two-temperature synthetic colors for our models using empirically-calibrated color tables. We describe the physical ingredients included in the SPOTS models and compare their predictions to other modern evolution codes. Finally, we apply these models to several open questions in the field of active stars, including the radii of young eclipsing binaries, the color scale of pre-main sequence stars, and the existence of sub-subgiants, demonstrating that our models can explain many peculiar features of active stars.
Weak-type estimates for the Bergman projection on the polydisc and the Hartogs triangle

In this paper, we investigate the weak-type regularity of the Bergman projection. The two domains we focus on are the polydisc and the Hartogs triangle. For the polydisc we provide a proof that the weak-type behavior is of "$L\log L$" type. This result is likely known to the experts, but does not appear to be in the literature. For the Hartogs triangle we show that the operator is of weak-type $(4,4)$; settling the question of the behavior of the projection at this endpoint. At the other endpoint of interest, we show that the Bergman projection is not of weak-type $(\frac{4}{3}, \frac{4}{3})$ and provide evidence as to what the correct behavior at this endpoint might be.
JSJ decompositions of quadratic Baumslag-Solitar groups

Generalized Baumslag–Solitar groups are defined as fundamental groups of graphs of groups with infinite cyclic vertex and edge groups. Forester [6] proved that in most cases the defining graphs are cyclic JSJ decompositions, in the sense of Rips and Sela. Here we extend Forester’s results to graphs of groups with vertex groups that can be either infinite cyclic or quadratically hanging surface groups.
Hybrid Feature Learning for Handwriting Verification

We propose an effective Hybrid Deep Learning (HDL) architecture for the task of determining the probability that a questioned handwritten word has been written by a known writer. HDL is an amalgamation of Auto-Learned Features (ALF) and Human-Engineered Features (HEF). To extract auto-learned features we use two methods: First, Two Channel Convolutional Neural Network (TC-CNN); Second, Two Channel Autoencoder (TC-AE). Furthermore, human-engineered features are extracted by using two methods: First, Gradient Structural Concavity (GSC); Second, Scale Invariant Feature Transform (SIFT). Experiments are performed by complementing one of the HEF methods with one ALF method on 150000 pairs of samples of the word "AND" cropped from handwritten notes written by 1500 writers. Our results indicate that HDL architecture with AE-GSC achieves 99.7% accuracy on seen writer dataset and 92.16% accuracy on shuffled writer dataset which out performs CEDAR-FOX, as for unseen writer dataset, AE-SIFT performs comparable to this sophisticated handwriting comparison tool.
On the subsystem formulation of linear-response time-dependent DFT.

A new and thorough derivation of linear-response subsystem time-dependent density functional theory (TD-DFT) is presented and analyzed in detail. Two equivalent derivations are presented and naturally yield self-consistent subsystem TD-DFT equations. One reduces to the subsystem TD-DFT formalism of Neugebauer [J. Chem. Phys.126, 134116 (Year: 2007)10.1063/1.2713754]. The other yields Dyson type equations involving three types of subsystem response functions: coupled, uncoupled, and Kohn–Sham. The Dyson type equations for subsystem TD-DFT are derived here for the first time. The response function formalism reveals previously hidden qualities and complications of subsystem TD-DFT compared with the regular TD-DFT of the supersystem. For example, analysis of the pole structure of the subsystem response functions shows that each function contains information about the electronic spectrum of the entire supersystem. In addition, comparison of the subsystem and supersystem response functions shows that, while the correlated response is subsystem additive, the Kohn–Sham response is not. Comparison with the non-subjective partition DFT theory shows that this non-additivity is largely an artifact introduced by the subjective nature of the density partitioning in subsystem DFT.
The de Rham functor for logarithmic D-modules

In the first part we deepen the six-functor theory of (holonomic) logarithmic D-modules, in particular with respect to duality and pushforward along projective morphisms. Then, inspired by work of Ogus, we define a logarithmic analogue of the de Rham functor, sending logarithmic D-modules to certain graded sheaves on the so-called Kato–Nakayama space. For holonomic modules we show that the associated sheaves have finitely generated stalks and that the de Rham functor intertwines duality for D-modules with a version of Poincare–Verdier duality on the Kato–Nakayama space. Finally, we explain how the grading on the Kato–Nakayama space is related to the classical Kashiwara–Malgrange V-filtration for holonomic D-modules.
Bounded Residual Gradient Networks (BReG-Net) for Facial Affect Computing

Residual-based neural networks have shown remarkable results in various visual recognition tasks including Facial Expression Recognition (FER). Despite the tremendous efforts have been made to improve the performance of FER systems using DNNs, existing methods are not generalizable enough for practical applications. This paper introduces Bounded Residual Gradient Networks (BReG-Net) for facial expression recognition, in which the shortcut connection between the input and the output of the ResNet module is replaced with a differentiable function with a bounded gradient. This configuration prevents the network from facing the vanishing or exploding gradient problem. We show that utilizing such non-linear units will result in shallower networks with better performance. Further, by using a weighted loss function which gives a higher priority to less represented categories, we can achieve an overall better recognition rate. The results of our experiments show that BReG-Nets outperform state-of-the-art methods on three publicly available facial databases in the wild, on both the categorical and dimensional models of affect.
A Reanalysis of Small-Scale Velocity Dispersion in the CfA1 Survey

The velocity dispersion of galaxies on scales of r D 1 h~1 Mpc, may be estimated from the p 12 (r), anisotropy of the galaxy-galaxy correlation function in redshift space. We present a reanalysis of the CfA1 survey in which we correct an error in the original analysis of Davis & Peebles. We give a detailed breakdown of how the value of depends on various aspects of the way in which corrections for p 12 (r) infall into the Virgo Cluster are applied. We -nd that is extremely sensitive to the details of these p 12 (r) corrections. We conclude that a robust value of cannot be obtained from this survey. p 12 Subject headings: cosmology: observations E galaxies: clusters: general E galaxies: distances and redshifts E large-scale structure of universe
Fitting rectangles under vulnerability curves: Optimal water flow through plants

We study an optimization problem for a model of steady state water transport through plants that maximizes water flow subject to the constraints on hydraulic conductance due to vulnerability to embolism (air blockage of conduits). The model has an elementary geometric interpretation, and exhibits bottleneck behavior where one of the plant segments limits the overall optimal flow, sometimes in a counterintuitive way. The results show good agreement with experimental measurements and provide support for the hypothesis that leaves serve as a safety buffer protecting stems against excessive embolism.
AB INITIO PULSAR MAGNETOSPHERE: The ROLE of GENERAL RELATIVITY

It has recently been demonstrated that self-consistent particle-in-cell simulations of low-obliquity pulsar magnetospheres in flat spacetime show weak particle acceleration and no pair production near the poles. We investigate the validity of this conclusion in a more realistic spacetime geometry via general-relativistic particle-in-cell simulations of the aligned pulsar magnetosphere with pair formation. We find that the addition of the frame-dragging effect makes the local current density along the magnetic field larger than the Goldreich–Julian value, which leads to unscreened parallel electric fields and the ignition of a pair cascade. When pair production is active, we observe field oscillations in the open field bundle, which could be related to pulsar radio emission. We conclude that general-relativistic effects are essential for the existence of the pulsar mechanism in low-obliquity rotators.
The Third Order Helicity of Magnetic Fields via Link Maps

We introduce an alternative approach to the third order helicity of a volume preserving vector field B, which leads us to a lower bound for the L 2-energy of B. The proposed approach exploits correspondence between the Milnor $${\bar{\mu}_{123}}$$ -invariant for 3-component links and the homotopy invariants of maps to configuration spaces, and we provide a simple geometric proof of this fact in the case of Borromean links. Based on these connections we develop a formulation for the third order helicity of B on invariant unlinked domains of B, and provide Arnold’s style ergodic interpretation of this invariant as an average asymptotic $${\bar{\mu}_{123}}$$ -invariant of orbits of B.
Molecular Assembly of Ground-State Cooled Single Atoms

Researchers have created a molecule in a single, precisely characterized quantum state by merging two carefully prepared atoms.
Shear-Induced Chaos

Guided by a geometric understanding developed in earlier works of Wang and Young, we carry out numerical studies of shear-induced chaos in several parallel but different situations. The settings considered include periodic kicking of limit cycles, random kicks at Poisson times and continuous-time driving by white noise. The forcing of a quasi-periodic model describing two coupled oscillators is also investigated. In all cases, positive Lyapunov exponents are found in suitable parameter ranges when the forcing is suitably directed.
Comments on fractional instantons in N=2 gauge theories

N=1★ gauge theories are believed to have fractional instanton contributions in the confining vacua. D3 brane probe computations in gravitation dual of large-N N=2★ gauge theories point to the absence of such contributions in the low energy gauge dynamics. We study fractional instantons in N=2 SU(2) Yang–Mills theory from the field theoretical perspective. We present new solutions to the Seiberg–Witten SU(2) monodromy problem with the same perturbative asymptotic, a massless monopole and a dyon singularity on the moduli space, and fractional instanton corrections to N=2 prepotential in the semi-classical region of the moduli space. We show that fractional instantons lead to infinite monopole (dyon) condensate in mass deformed N=2 gauge theories.
Implications of a frame dependent gravitational effective action for perturbations on the Robertson–Walker metric

In earlier work we showed that a frame dependent effective action motivated by the postulates of three-space general coordinate invariance and Weyl scaling invariance exactly mimics a cosmological ...
Gluing and wormholes for the Einstein constraint equations

We establish a general gluing theorem for constant mean curvature solutions of the vacuum Einstein constraint equations. This allows one to take connected sums of solutions or to glue a handle (wormhole) onto any given solution. Away from this handle region, the initial data sets we produce can be made as close as desired to the original initial data sets. These constructions can be made either when the initial manifold is compact or asymptotically Euclidean or asymptotically hyperbolic, with suitable corresponding conditions on the extrinsic curvature. In the compact setting a mild nondegeneracy condition is required. In the final section of the paper, we list a number ways this construction may be used to produce new types of vacuum spacetimes.
Chemical Abundance Evidence of Enduring High Star Formation Rates in an Early-type Galaxy: High [Ca/Fe] in NGC 5128 Globular Clusters

We present [Fe/H], ages, and Ca abundances for an initial sample of 10 globular clusters in NGC 5128 obtained from high resolution, high signal-to-noise ratio echelle spectra of their integrated light. All abundances and ages are obtained using our original technique for high resolution integrated light abundance analysis of globular clusters. The clusters have a range in [Fe/H] between 1.6 to 0.2. In this sample, the average [Ca/Fe] for clusters with [Fe/H]< 0.4 is +0.37±0.07, while the average [Ca/Fe] in our MW and M31 GC samples is +0.29 ±0.09 and +0.24 ±0.10, respectively. This may imply a more rapid chemical enrichment history for NGC 5128 than for either the Milky Way or M31.This sample provides the first quantitative picture of the chemical history of NGC 5128 that is directly comparable to what is available for the Milky Way. Data presented here were obtained with the MIKE echelle spectrograph on the Magellan Clay Telescope. Subject headings: galaxies: abundances— galaxies: elliptical and lenticular, cD— galaxies: individual (NGC5128) — galaxies: star clusters: general — galaxies: stellar content
Radial Basis Function ENO and WENO Finite Difference Methods Based on the Optimization of Shape Parameters

We present adaptive finite difference ENO/WENO methods with infinitely smooth radial basis functions (RBFs). These methods slightly perturb the polynomial reconstruction coefficients with RBFs as the reconstruction basis and enhance accuracy in the smooth region by locally optimizing the shape parameters. Compared to the classical ENO/WENO methods, the RBF-ENO/WENO methods provide more accurate reconstructions and sharper solution profiles near the jump discontinuity. Furthermore the RBF-ENO/WENO methods are easy to implement in the existing classical ENO/WENO code. The numerical results in 1D and 2D presented in this paper show that the proposed finite difference RBF-ENO/WENO methods perform better than the classical ENO/WENO methods.
The Virial Expansion of a Dilute Bose Gas in Two Dimensions

In terms of the s-wave phase shift of the two-body scattering at thermal wavelength, a systematic perturbative expansion of the Virial coefficients is developed for a two-dimensional dilute system of bosons in its gaseous phase at low temperature. The thermodynamic functions are calculated to the second order of the expansion parameter. The observability of the universal low energy limit of the two dimensional phase shift with a quasi-two dimensional atomic gas in an anisotropic trap is discussed.
Maximum-Likelihood Power-Distortion Monitoring for GNSS-Signal Authentication

We propose an extension to the so-called power-distortion (PD) detector. The PD detector jointly monitors received power and correlation-profile distortion to detect the presence of global navigation satellite system (GNSS) carryoff-type spoofing, jamming, or multipath. We show that classification performance can be significantly improved by replacing the PD detector's symmetric-difference (SD) based distortion measurement with one based on the postfit residuals of the maximum-likelihood estimate of a single-signal correlation function model. We call the improved technique the power-distortion maximum-likelihood (PD-ML) detector. In direct comparison with the PD detector, the PD-ML detector exhibits improved classification accuracy when tested against an extensive library of recorded field data. In particular, it is 1) significantly more accurate at distinguishing a spoofing attack from a jamming attack; 2) better at distinguishing multipath-afflicted data from interference-free data; and 3) less likely to issue a false alarm by classifying multipath as spoofing. The PD-ML detector achieves this improved performance at the expense of additional computational complexity.
SPITZER OBSERVATIONS OF MOLECULAR HYDROGEN IN INTERACTING SUPERNOVA REMNANTS

With Spitzer IRS, we have obtained sensitive low-resolution spectroscopy from 5 to 35 μm for six supernova remnants (SNRs) that show evidence of shocked molecular gas: Kes 69, 3C 396, Kes 17, G346.6–0.2, G348.5–0.0, and G349.7+0.2. Bright pure rotational lines of molecular hydrogen are detected at the shock front in all remnants, indicative of radiative cooling from shocks interacting with dense clouds. We find the excitation of H_2 S(0)-S(7) lines in these SNRs requires two nondissociative shock components: a slow 10 km s^(–1) C-shock through clumps of density 10^6 cm^(–3), and a faster 40-70 km s^(–1) C-shock through a medium of density 10^4 cm^(–3). The ortho-to-para ratio for H_2 in the warm shocked gas is typically found to be much less than the LTE value, suggesting that these SNRs are propagating into cold quiescent clouds. Additionally, a total of 13 atomic fine-structure transitions of Ar^+, Ar^(++), Fe^+, Ne^+, Ne^(++), S^(++), and Si^+ are detected. The ionic emitting regions are spatially segregated from the molecular emitting regions within the IRS slits. The presence of ionic lines with high appearance potential requires the presence of much faster, dissociative shocks through a lower density medium. The IRS slits are sufficiently wide to include regions outside the SNR which permits emission from diffuse gas around the remnants to be separated from the shocked emission. We find the diffuse H_2 gas projected outside the SNR is excited to a temperature of 100-300 K with a warm gas fraction of at least 0.5%-15% along the line of sight.
Flat Low-Loss Silicon Gradient Index Lens for Millimeter and Submillimeter Wavelengths

We present the design, simulation, and planned fabrication process of a flat high resistivity silicon gradient index (GRIN) lens for millimeter and submillimeter wavelengths with very low absorption losses. The gradient index is created by sub wavelength holes whose size increases with the radius of the lens. The effective refractive index created by the subwavelength holes is constant over a very wide bandwidth, allowing the fabrication of achromatic lenses up to submillimeter wavelengths. The designed GRIN lens was successfully simulated and shows an expected efficiency better than that of a classic silicon plano-concave spherical lens with approximately the same thickness and focal length. Deep reactive ion etching (DRIE) and wafer-bonding of several patterned wafers will be used to realize our first GRIN lens prototype.
Elastohydrodynamics of a sliding, spinning and sedimenting cylinder near a soft wall

We consider the motion of a fluid-immersed negatively buoyant particle in the vicinity of a thin compressible elastic wall, a situation that arises in a variety of technological and natural settings. We use scaling arguments to establish different regimes of sliding, and complement these estimates using thin-film lubrication dynamics to determine an asymptotic theory for the sedimentation, sliding and spinning motions of a cylinder. The resulting theory takes the form of three coupled nonlinear singular-differential equations. Numerical integration of the resulting equations confirms our scaling relations and further yields a range of unexpected behaviours. Despite the low-Reynolds-number feature of the flow, we demonstrate that the particle can spontaneously oscillate when sliding, can generate lift via a Magnus-like effect, can undergo a spin-induced reversal effect and also shows an unusual sedimentation singularity. Our description also allows us to address a sedimentation–sliding transition that can lead to the particle coasting over very long distances, similar to certain geophysical phenomena. Finally, we show that a small modification of our theory allows us to generalize the results to account for additional effects such as wall poroelasticity.
Slow dynamics in a two-dimensional Anderson-Hubbard model

We study the real-time dynamics of a two-dimensional Anderson-Hubbard model using nonequilibrium self-consistent perturbation theory within the second-Born approximation. When compared with exact diagonalization performed on small clusters, we demonstrate that for strong disorder this technique approaches the exact result on all available timescales, while for intermediate disorder, in the vicinity of the many-body localization transition, it produces quantitatively accurate results up to nontrivial times. Our method allows for the treatment of system sizes inaccessible by any numerically exact method and for the complete elimination of finite-size effects for the times considered. We show that for a sufficiently strong disorder the system becomes nonergodic, while for intermediate disorder strengths and for all accessible timescales transport in the system is strictly subdiffusive. We argue that these results are incompatible with a simple percolation picture, but are consistent with the heuristic random resistor network model where subdiffusion may be observed for long times until a crossover to diffusion occurs. The prediction of slow finite-time dynamics in a two-dimensional interacting and disordered system can be directly verified in future cold-atoms experiments.
Maximum Angular Separation Epochs for Exoplanet Imaging Observations

Direct imaging of exoplanets presents both significant challenges and significant gains. The advantages primarily lie in receiving emitted and, with future instruments, reflected photons at phase angles not accessible by other techniques, enabling the potential for atmospheric studies and the detection of rotation and surface features. The challenges are numerous and include coronagraph development and achieving the necessary contrast ratio. Here, we address the specific challenge of determining epochs of maximum angular separation for the star and planet. We compute orbital ephemerides for known transiting and radial velocity planets, taking Keplerian orbital elements into account. We provide analytical expressions for angular star--planet separation as a function of the true anomaly, including the locations of minimum and maximum. These expressions are used to calculate uncertainties for maximum angular separation as a function of time for the known exoplanets, and we provide strategies for improving ephemerides with application to proposed and planned imaging missions.
On Melonic Supertensor Models

We investigate a class of supersymmetric quantum mechanical theories (with two supercharges) having tensor-valued degrees of freedom which are dominated by melon diagrams in the large N limit. One motivation was to examine the interplay between supersymmetry and melonic dominance and potential implications for building toy models of holography. We find a definite tension between supersymmetry (with dynamical bosons) and melonic dominance in this class of systems. More specifically, our theories attain a low energy non-supersymmetric conformal fixed point. The origin of supersymmetry breaking lies in the need to regularize bosonic and fermionic degrees of freedom independently. We investigate various aspects of the low energy spectrum and also comment on related examples with different numbers of supercharges. Along the way we also derive some technical results for SL(2, ℝ) wavefunctions for fermionic excitations.
Natural supersymmetry in warped space

We explore the possibility of solving the hierarchy problem by combining the paradigms of supersymmetry and compositeness. Both paradigms are under pressure from the results of the Large Hadron Collider (LHC), and combining them allows both a higher confinement scale — due to effective supersymmetry in the low energy theory — and heavier superpartners — due to the composite nature of the Higgs boson — without sacrificing naturalness. The supersymmetric Randall-Sundrum model provides a concrete example where calculations are possible, and we pursue a realistic model in this context. With a few assumptions, we are led to a model with bulk fermions, a left-right gauge symmetry in the bulk, and supersymmetry breaking on the UV brane. The first two generations of squarks are decoupled, reducing LHC signatures but also leading to quadratic divergences at two loops. The model predicts light W ′ and Z ′ gauge bosons, and present LHC constraints on exotic gauge bosons imply a high confinement scale and mild tuning from the quadratic divergences, but the model is otherwise viable. We also point out that R-parity violation can arise naturally in this context.
Competing Orders in PZN-xPT and PMN-xPT Relaxor Ferroelectrics

Neutron and x-ray scattering studies on relaxor ferroelectric systems Pb(Zn 1/3 Nb 2/3 )O 3 (PZN), Pb(Mg 1/3 Nb 2/3 )O 3 (PMN), and their solid solutions with PbTiO 3 (PT) have shown that inhomogeneities and disorder play important roles in the materials properties. Although a long-range polar order can be established at low temperature – sometimes with the help of an external electric field; short-range local structures called the “polar nano-regions” (PNR) still persist. Both the bulk structure and the PNR have been studied in details. The coexistence and competition of long- and short-range polar orders and how they affect the structural and dynamical properties of relaxor materials are discussed.
Non-trivial solutions to a linear equation in integers

For k>=3 let A \subset [1,N] be a set not containing a solution to a_1 x_1+...+a_k x_k=a_1 x_{k+1}+...+a_k x_{2k} in distinct integers. We prove that there is an epsilon>0 depending on the coefficients of the equation such that every such A has O(N^{1/2-epsilon}) elements. This answers a question of I. Ruzsa.
The Aemulus Project. I. Numerical Simulations for Precision Cosmology

US Department of Energy [DE-AC02-76SF00515]; NSF [AST-1211889]; DOE [DE-SC0015975]; Sloan Foundation [FG-2016-6443]; Samuel P. Langley PITT PACC Postdoctoral Fellowship; Office of Science of the US Department of Energy [DE-AC02-05CH11231]
The singularity structure of scale-invariant rank-2 Coulomb branches

We compute the spectrum of scaling dimensions of Coulomb branch operators in 4d rank-2 $$ \mathcal{N}=2 $$ superconformal field theories. Only a finite rational set of scaling dimensions is allowed. It is determined by using information about the global topology of the locus of metric singularities on the Coulomb branch, the special Kahler geometry near those singularities, and electric-magnetic duality monodromies along orbits of the U(1)R symmetry. A set of novel topological and geometric results are developed which promise to be useful for the study and classification of Coulomb branch geometries at all ranks.
GOLDEN RATIO CONTROLLED CHAOS IN SUPERSYMMETRIC DYNAMICS

We construct supersymmetric Lagrangians for the recently constructed off-shell worldline N = 3 supermultiplet for I = 1, 2, 3, where and are standard, Salam–Strathdee superfields: fermionic and bosonic. Already the Lagrangian bilinear in component fields exhibits a total of thirteen free parameters, seven of which specify Zeeman-like coupling to external (magnetic) fluxes. All but special subsets of this parameter space describe aperiodic oscillatory response, some of which are controlled by the "golden ratio," φ≈1.61803. We also show that all of these Lagrangians admit an N = 3 →4 supersymmetry extension, while a subset admits two inequivalent such extensions.
Dense matter equation of state for neutron star mergers

In simulations of binary neutron star mergers, the dense matter equation of state (EOS) is required over wide ranges of density and temperature as well as under conditions in which neutrinos are trapped, and the effects of magnetic fields and rotation prevail. Here we assess the status of dense matter theory and point out the successes and limitations of approaches currently in use. A comparative study of the excluded volume (EV) and virial approaches for the $ np\alpha$ system using the equation of state of Akmal, Pandharipande and Ravenhall for interacting nucleons is presented in the sub-nuclear density regime. Owing to the excluded volume of the $ \alpha$-particles, their mass fraction vanishes in the EV approach below the baryon density 0.1fm^-3, whereas it continues to rise due to the predominantly attractive interactions in the virial approach. The EV approach of Lattimer et al. is extended here to include clusters of light nuclei such as d, 3H and 3He in addition to $ \alpha$-particles. Results of the relevant state variables from this development are presented and enable comparisons with related but slightly different approaches in the literature. We also comment on some of the sweet and sour aspects of the supra-nuclear EOS. The extent to which the neutron star gravitational and baryon masses vary due to thermal effects, neutrino trapping, magnetic fields and rotation are summarized from earlier studies in which the effects from each of these sources were considered separately. Increases of about $ 20\% (\gtrsim 50\%)$ occur for rigid (differential) rotation with comparable increases occurring in the presence of magnetic fields only for fields in excess of $ 10^{18}$ Gauss. Comparatively smaller changes occur due to thermal effects and neutrino trapping. Some future studies to gain further insight into the outcome of dynamical simulations are suggested.
Post-processing of the HST STIS coronagraphic observations

In the past 20 years, the Hubble Space Telescope (HST) STIS coronagraphic instrument has observed more than 100 stars, obtaining more than 4,000 readouts since its installment on HST in 1997 and the numbers are still increasing. We reduce the whole STIS coronagraphic archive at the most commonly observed positions (Wedge A0.6 and A1.0) with new post-processing methods, and present our results here. We are able to recover all of the 32 previously reported circumstellar disks, and obtain better contrast close to the star. For some of the disks, our results are limited by the over subtraction of the methods, and therefore the major regions of the disks can be recovered except the faintest regions. We also explain our efforts in the calibration of its new BAR5 occulting position, enabling STIS to explore inner regions as close as 0.2 00 .
Strain control of oxygen vacancies in epitaxial strontium cobaltite films

The ability to manipulate oxygen anion defects rather than metal cations in complex oxides can facilitate creating new functionalities critical for emerging energy and device technologies. However, the difficulty in activating oxygen at reduced temperatures hinders the deliberate control of important defects, oxygen vacancies. Here, strontium cobaltite (SrCoOx) is used to demonstrate that epitaxial strain is a powerful tool for manipulating the oxygen vacancy concentration even under highly oxidizing environments and at annealing temperatures as low as 300 °C. By applying a small biaxial tensile strain (2%), the oxygen activation energy barrier decreases by ≈30%, resulting in a tunable oxygen deficient steady-state under conditions that would normally fully oxidize unstrained cobaltite. These strain-induced changes in oxygen stoichiometry drive the cobaltite from a ferromagnetic metal towards an antiferromagnetic insulator. The ability to decouple the oxygen vacancy concentration from its typical dependence on the operational environment is useful for effectively designing oxides materials with a specific oxygen stoichiometry.
Human Atlas: A Tool for Mapping Social Networks

Most social network analyses focus on online social networks. While these networks encode important aspects of our lives they fail to capture many real-world social connections. Most of these connections are, in fact, public and known to the members of the community. Mapping them is a task very suitable for crowdsourcing: it is easily broken down in many simple and independent subtasks. Due to the nature of social networks-presence of highly connected nodes and tightly knit groups-if we allow users to map their immediate connections and the connections between them, we will need few participants to map most connections within a community. To this end, we built the Human Atlas, a web-based tool for mapping social networks. To test it, we partially mapped the social network of the MIT Media Lab. We ran a user study and invited members of the community to use the tool. In 4.6 man-hours, 22 participants mapped 984 connections within the lab, demonstrating the potential of the tool.
Fast reachable set approximations via state decoupling disturbances

With the recent surge of interest in using robotics and automation for civil purposes, providing safety and performance guarantees has become extremely important. In the past, differential games have been successfully used for the analysis of safety-critical systems. In particular, the Hamilton-Jacobi (HJ) formulation of differential games provides a flexible way to compute the reachable set, which can characterize the set of states which lead to either desirable or undesirable configurations, depending on the application. While HJ reachability is applicable to many small practical systems, the curse of dimensionality prevents the direct application of HJ reachability to many larger systems. To address computation complexity issues, various efficient computation methods in the literature have been developed for approximating or exactly computing the solution to HJ partial differential equations, but only when the system dynamics are of specific forms. In this paper, we propose a flexible method to trade off optimality with computation complexity in HJ reachability analysis. To achieve this, we propose to simplify system dynamics by treating state variables as disturbances. We prove that the resulting approximation is conservative in the desired direction, and demonstrate our method using a four-dimensional plane model.
Landslide tsunamis in lakes

Landslides plunging into lakes and reservoirs can result in extreme wave runup at the shores. This phenomenon has claimed lives and caused damage to near-shore properties. Landslide tsunamis in lakes are different from typical earthquake tsunamis in the open ocean in that (i) the affected areas are usually within the near field of the source, (ii) the highest runup occurs within the time period of the geophysical event, and (iii) the enclosed geometry of a lake does not let the tsunami energy escape. To address the problem of transient landslide tsunami runup and to predict the resulting inundation, we utilize a nonlinear model equation in the Lagrangian frame of reference. The motivation for using such a scheme lies in the fact that the runup on an inclined boundary is directly and readily computed in the Lagrangian framework without the need to resort to approximations. In this work, we investigate the inundation patterns due to landslide tsunamis in a lake. We show by numerical computations that Airy’s approximation of an irrotational theory using Lagrangian coordinates can legitimately predict runup of large amplitude. We also demonstrate that in a lake of finite size the highest runup may be magnified by constructive interference between edge waves that are trapped along the shore and multiple reflections of outgoing waves from opposite shores, and may occur somewhat after the first inundation.
Observational Evidence for Self-generation of Small-scale Magnetic Flux Ropes from Intermittent Solar Wind Turbulence

We present unique {and additional} observational evidence for the self-generation of small-scale coherent magnetic flux rope structures in the solar wind. Such structures with durations between 9 and 361 minutes are identified from Wind in-situ spacecraft measurements through the Grad-Shafranov (GS) reconstruction approach. The event occurrence counts are on the order of 3,500 per year on average and have a clear solar cycle dependence. We build a database of small-scale magnetic flux ropes from twenty-year worth of Wind spacecraft data. We show a power-law distribution of the wall-to-wall time corresponding well to the inertial range turbulence, which agrees with relevant observations and numerical simulation results. We also provide the axial current density distribution from the GS-based observational analysis, which yields a non-Gaussian probability density function consistent with numerical simulation results.
Scalar conservation laws with monotone pure-jump Markov initial conditions

In 2010 Menon and Srinivasan published a conjecture for the statistical structure of solutions $$\rho $$ to scalar conservation laws with certain Markov initial conditions, proposing a kinetic equation that should suffice to describe $$\rho (x,t)$$ as a stochastic process in x with t fixed. In this article we verify an analogue of the conjecture for initial conditions which are bounded, monotone, and piecewise constant. Our argument uses a particle system representation of $$\rho (x,t)$$ over $$0 \le x \le L$$ for $$L > 0$$ , with a suitable random boundary condition at $$x = L$$ .
Recent advancements in the study of intrinsic magnetic topological insulators and magnetic Weyl semimetals

The studies of topological insulators (TI) and topological semimetals have been at frontiers of condensed matter physics and material science. Both classes of materials are characterized by robust surface states created by the topology of the bulk band structures and exhibit exotic transport properties. When magnetism is present in topological materials and breaks the time-reversal symmetry, more exotic quantum phenomena can be generated, e.g., quantum anomalous Hall effect (QAHE), axion insulator, and large intrinsic AHE. In this research update, we briefly summarize the recent research progress in magnetic topological materials, including intrinsic magnetic TI and magnetic Weyl semimetals.
Quantifying “cliffs” in design space

Purpose – The purpose of this paper is to study the regions of parameter space of engineering design in which performance is sensitive to design parameters. Some of these parameters (for example, the dimensions and compositions of components) constitute the design, but others are intrinsic properties of materials or Nature. The paper is concerned with narrow regions of parameter space, “cliffs”, in which performance (some measure of the final state of a system, such as ignition or nonignition of a flammable gas, or failure or nonfailure of a ductile material subject to tension) is a sensitive function of the parameters. In these regions, performance is also sensitive to uncertainties in the parameters. This is particularly important for intrinsically indeterminate systems, those whose performance is not predictable from measured initial conditions and is not reproducible. Design/methodology/approach – We develop models of ignition of a flammable mixture and of failure in plastic flow under tension. We ide...
Relationship of EUV Irradiance Coronal Dimming Slope and Depth to Coronal Mass Ejection Speed and Mass

Extreme ultraviolet (EUV) coronal dimmings are often observed in response to solar eruptive events. These phenomena can be generated via several different physical processes. For space weather, the most important of these is the temporary void left behind by a coronal mass ejection (CME). Massive, fast CMEs tend to leave behind a darker void that also usually corresponds to minimum irradiance for the cooler coronal emissions. If the dimming is associated with a solar are, as is often the case, the are component of the irradiance light curve in the cooler coronal emission can be isolated and removed using simultaneous measurements of warmer coronal lines. We apply this technique to 37dimming events identified during two separate two-week periods in 2011, plus an event on 2010 August 7 analyzed in a previous paper, to parameterize dimming in terms of depth and slope. We provide statistics on which combination of wavelengths worked best for the flare-removal method, describe the fitting methods applied to the dimming light curves, and compare the dimming parameters with corresponding CME parameters of mass and speed. The best linear relationships found are nu(sub CME) [km/s] approx. equals 2.36 x 10 6 [km/%] x s(sub dim) [%/s] m(sub CME) [g] approx. equals 2.59 x 10(exp.15 [g/%] x the square root of d(sub dim) [%].These relationships could be used for space weather operations of estimating CME mass and speed using near-real-time irradiance dimming measurements.
Metallicity of Red Giants in the Galactic Bulge from Near-Infrared Spectroscopy

We present moderate-resolution (λ/Δλ = 1300–4800) K-band spectra of more than 110 M giants in Galactic bulge fields interior to -4° (560 pc) and as close as within 02 (28 pc) of the Galactic center. From the equivalent widths of three features in these spectra, EW(Na), EW(Ca), and EW(CO) we calculate metallicities for the stars with a new calibration derived by Stephens et al. from globular clusters. The mean metallicity for each field is in good agreement with the recent results from Frogel et al. based on the slope of the giant branch method. We find no evidence for a metallicity gradient along the minor or major axes of the inner bulge (R < 560 pc). The lack of a metallicity gradient in the inner bulge is not predicted by a theoretical model developed by Molla et al. for a bulge formed by dissipative collapse. A metallicity gradient along the minor axis found by Frogel et al. only arises when fields located at larger galactic radius are included. However, these more distant fields are located outside of the infrared bulge defined by the COBE/DIRBE observations. We compute the metallicity distribution for the inner bulge and find a mean value of -0.21 dex with a dispersion of ±0.30 dex, close to the values found in 1996 by Sadler et al. for Baade's window. Unlike the absence of a gradient, these values are close to theoretical predictions for a bulge formed by dissipative collapse.
SubTSBR to tackle high noise and outliers for data-driven discovery of differential equations

Abstract Data-driven discovery of differential equations has been an emerging research topic. We propose a novel algorithm subsampling-based threshold sparse Bayesian regression (SubTSBR) to tackle high noise and outliers. The subsampling technique is used for improving the accuracy of the Bayesian learning algorithm. It has two parameters: subsampling size and the number of subsamples. When the subsampling size increases with fixed total sample size, the accuracy of our algorithm goes up and then down. When the number of subsamples increases, the accuracy of our algorithm keeps going up. We demonstrate how to use our algorithm step by step and compare our algorithm with threshold sparse Bayesian regression (TSBR) for the discovery of differential equations. We show that our algorithm produces better results. We also discuss the merits of discovering differential equations from data and demonstrate how to discover models with random initial and boundary condition as well as models with bifurcations. The numerical examples are: (1) predator-prey model with noise, (2) shallow water equations with outliers, (3) heat diffusion with random initial and boundary condition, and (4) fish-harvesting problem with bifurcations.
Dynamics of diffusive cell signaling relays

In biological contexts as diverse as development, apoptosis, and synthetic microbial consortia, collections of cells or subcellular components have been shown to overcome the slow signaling speed of simple diffusion by utilizing diffusive relays, in which the presence of one type of diffusible signaling molecule triggers participation in the emission of the same type of molecule. This collective effect gives rise to fast-traveling diffusive waves. Here, in the context of cell signaling, we show that system dimensionality - the shape of the extracellular medium and the distribution of cells within it - can dramatically affect the wave dynamics, but that these dynamics are insensitive to details of cellular activation. As an example, we show that neutrophil swarming experiments exhibit dynamical signatures consistent with the proposed signaling motif. We further show that cell signaling relays generate much steeper concentration profiles than does simple diffusion, which may facilitate neutrophil chemotaxis.
An adjunctive therapy administered with an antibiotic prevents enrichment of antibiotic-resistant clones of a colonizing opportunistic pathogen.

Antibiotics are essential for treating infections. But their use can inadvertently lead to the emergence of antibiotic-resistant bacteria that do not respond to antibiotic drugs, making infections with these bacteria difficult or impossible to treat. Finding ways to prevent antibiotic resistance is critical to preserving the effectiveness of antibiotics. Many bacteria that cause infections in hospitals live in the intestines, where they are harmless. But these bacteria can cause life-threatening infections when they get into the bloodstream. When patients with bloodstream infections receive antibiotics, the bacteria in their intestines are also exposed to the drugs. This can kill off all antibiotic-susceptible bacteria, leaving behind only bacteria that have mutations that allow them to survive the drugs. These drug-resistant bacteria can then spread to other patients causing hard-to-treat infections. To stop this cycle of antibiotic treatment and antibiotic resistance, Morley et al. tested whether giving a drug called cholestyramine with intravenous antibiotics could protect the gut bacteria. In the experiments, mice were treated systemically with an antibiotic called daptomycin, which caused the growth of daptomycin-resistant strains of bacteria in the mice’s intestines. In the laboratory, Morley et al. discovered that cholestyramine can inactivate daptomycin. Giving the mice cholestyramine and daptomycin together prevented the growth of antibiotic-resistant bacteria in the mice's intestines. Moreover, cholestyramine is taken orally and is not absorbed into the blood. It therefore only inactivates the antibiotic in the gut, but not in the blood. The experiments provide preliminary evidence that giving cholestyramine with antibiotics might help prevent the spread of drug resistance. Cholestyramine is already used to lower cholesterol levels in people. More studies are needed to determine if cholestyramine can protect gut bacteria and prevent antibiotic resistance in people.