cssi/SciSciGPT-SciSciNet huggingface dataset:
A HEURISTIC QUANTUM THEORY OF THE INTEGER QUANTUM HALL EFFECT

Contrary to common belief, the current emitted by a contact embedded in a two-dimensional electron gas (2DEG) is quantized in the presence of electric and magnetic fields. This observation suggests a simple, clearly defined model for the quantum current through a Hall device that does not invoke disorder or interactions as the cause of the integer quantum Hall effect (QHE), but is based on a proper quantization of the classical electron drift motion. The theory yields a quantitative description of the breakdown of the QHE at high current densities that is in agreement with experimental data. Furthermore, several of its key points are in line with recent findings of experiments that address the dependency of the QHE on the 2DEG bias voltage and results that are not easily explained within the framework of conventional QHE models.
The L 2 Essential Spectrum of the 2D Euler Operator

Even in two dimensions, the spectrum of the linearized Euler operator is notoriously hard to compute. In this paper we give a new geometric calculation of the essential spectrum for 2D flows. This generalizes existing results—which are only available when the flow has arbitrarily long periodic orbits—and clarifies the role of individual streamlines in generating essential spectra.
Jet-induced star formation: Good news from big, bad black holes

We discuss obbservations and numerical simulations which show that radiative shocks in jet-cloud collisions can trigger the collapse of intergalactic clouds and subsequent star formation in low luminosity, ‘FR-I’ type, radio galaxies.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html
Disease spread over randomly switched large-scale networks

In this paper we study disease spread over a randomly switched network, which is modeled by a stochastic switched differential equation based on the so called Nintertwined model for disease spread over static networks. Assuming that all the edges of the network are independently switched, we present sufficient conditions for the convergence of infection probability to zero. Though the stability theory for switched linear systems can naively derive a sufficient condition for the convergence, the condition cannot be used for large-scale networks because, for a network with n agents, it requires computing the maximum real eigenvalue of a matrix of size exponential in n. On the other hand, our conditions that are based also on the spectral theory of random matrices can be checked by computing the maximum real eigenvalue of a matrix of size n.
N-body simulations of collective effects in spiral and barred galaxies

Abstract We present gravitational N -body simulations of the secular morphological evolution of disk galaxies induced by density wave modes. In particular, we address the demands collective effects place on the choice of simulation parameters, and show that the common practice of the use of a large gravity softening parameter was responsible for the failure of past simulations to correctly model the secular evolution process in galaxies, even for those simulations where the choice of basic state allows an unstable mode to emerge, a prerequisite for obtaining the coordinated radial mass flow pattern needed for secular evolution of galaxies along the Hubble sequence. We also demonstrate that the secular evolution rates measured in our improved simulations agree to an impressive degree with the corresponding rates predicted by the recently-advanced theories of dynamically-driven secular evolution of galaxies. The results of the current work, besides having direct implications on the cosmological evolution of galaxies, also shed light on the general question of how irreversibility emerges from a nominally reversible physical system.
Spin Physics through QCD Instantons

Abstract We review some aspects of spin physics where QCD instantons play an important role. In particular, their large contributions in semi-inclusive deep-inelastic scattering and polarized proton on proton scattering. We also review their possible contribution in the P -odd pion azimuthal charge correlations in peripheral A A scattering at collider energies.
A Comparison between Physics-based and Polytropic MHD Models for Stellar Coronae and Stellar Winds of Solar Analogs

The development of the Zeeman–Doppler Imaging (ZDI) technique has provided synoptic observations of surface magnetic fields of low-mass stars. This led the stellar astrophysics community to adopt modeling techniques that have been used in solar physics using solar magnetograms. However, many of these techniques have been neglected by the solar community due to their failure to reproduce solar observations. Nevertheless, some of these techniques are still used to simulate the coronae and winds of solar analogs. Here we present a comparative study between two MHD models for the solar corona and solar wind. The first type of model is a polytropic wind model, and the second is the physics-based AWSOM model. We show that while the AWSOM model consistently reproduces many solar observations, the polytropic model fails to reproduce many of them, and in the cases where it does, its solutions are unphysical. Our recommendation is that polytropic models, which are used to estimate mass-loss rates and other parameters of solar analogs, must first be calibrated with solar observations. Alternatively, these models can be calibrated with models that capture more detailed physics of the solar corona (such as the AWSOM model) and that can reproduce solar observations in a consistent manner. Without such a calibration, the results of the polytropic models cannot be validated, but they can be wrongly used by others.
Cosmological information in the intrinsic alignments of luminous red galaxies

The intrinsic alignments of galaxies are usually regarded as a contaminant to weak gravitational lensing observables. The alignment of Luminous Red Galaxies, detected unambiguously in observations from the Sloan Digital Sky Survey, can be reproduced by the linear tidal alignment model of Catelan, Kamionkowski & Blandford (2001) on large scales. In this work, we explore the cosmological information encoded in the intrinsic alignments of red galaxies. We make forecasts for the ability of current and future spectroscopic surveys to constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations (BAO) in the cross-correlation function of intrinsic alignments and the galaxy density fiel d. For the Baryon Oscillation Spectroscopic Survey, we find that the BAO signal in the intrinsic alignments is marg inally significant with a signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic survey following the EUCLID redshift selection function, we find si gnal-to-noise ratios of 12 and 15, respectively. Local type primordial non-Gaussianity, parametrized by fNL = 10, is only marginally significant in the intrinsic alignments signal with signal-to-noise ratios < 2 for the three surveys considered.
Structure-Based Modeling of SARS-CoV-2 Peptide/HLA-A02 Antigens

SARS-CoV-2-specific CD4 and CD8 T cells have been shown to be present in individuals with acute, mild and asymptomatic Coronavirus disease (COVID-19). Toward the development of diagnostic and therapeutic tools to fight COVID-19, it is important to predict and characterize T cell epitopes expressed by SARS-CoV-2. Here, we use RosettaMHC, a comparative modeling approach which leverages existing structures of peptide/MHC complexes available in the Protein Data Bank, to derive accurate 3D models for putative SARS-CoV-2 CD8 epitopes. We outline an application of our method to model 8-10 residue epitopic peptides predicted to bind to the common allele HLA-A*02:01, and we make our models publicly available through an online database (https://rosettamhc.chemistry.ucsc.edu). We further compare electrostatic surfaces with models of homologous peptide/HLA-A*02:01 complexes from human common cold coronavirus strains to identify epitopes which may be recognized by a shared pool of cross-reactive TCRs. As more detailed studies on antigen-specific T cell recognition become available, RosettaMHC models can be used to understand the link between peptide/HLA complex structure and surface chemistry with immunogenicity, in the context of SARS-CoV-2 infection.
Strain, Nano-Phase Separation, Multi-Scale Structures and Function of Advanced Materials

In advanced materials with interesting functionality a realization is growing that the properties depend sensitively on complex structures on different length-scales from atomic to macroscopic. The challenge to experimentalists is properly to characterize such materials. This will be a prerequisite to obtaining a complete theoretical understanding of these materials. It is particularly difficult because many of the existing technologies for studying a material’s structure quantitatively reveal only average properties such as the crystal structure. However, key information about higher level structures, potentially driving the interesting properties, is contained in deviations from this average picture. New approaches to studying structure are therefore required to solve this problem. A number of imaging techniques now exist such as TEM, STM, AFM and so on and these are proving to be extremely important. What is needed in addition is bulk probes that provide quantitative information about atomic structures in disordered systems. XAFS is an important technique for very short-range structure. Here we describe insights that we have gained from using the atomic pair distribution function (PDF) analysis of powder neutron and x-ray diffraction data. This technique is described in detail elsewhere. Here we mention only that it yields quantitative information about atomic structure on short
Characterizing atomic magnetic gradiometers for fetal magnetocardiography.

Atomic magnetometers (AMs) offer many advantages over superconducting quantum interference devices due to, among other things, having comparable sensitivity while not requiring cryogenics. One of the major limitations of AMs is the challenge of configuring them as gradiometers. We report the development of a spin-exchange relaxation free vector atomic magnetic gradiometer with a sensitivity of 3 fT cm−1 Hz−1/2 and common mode rejection ratio >150 in the band from DC to 100 Hz. We introduce a background suppression figure of merit for characterizing the performance of gradiometers. It allows for optimally setting the measurement baseline and for quickly assessing the advantage, if any, of performing a measurement in a gradiometric mode. As an application, we consider the problem of fetal magnetocardiography (fMCG) detection in the presence of a large background maternal MCG signal.
Interaction of Gravitational Waves with Charged Particles

It is shown here that a cloud of charged particles could in principle absorb energy from gravitational waves (GWs) incident upon it, resulting in wave attenuation. This could in turn have implications for the interpretation of future data from early universe GWs.
The Effect Of Carbon Nanotube/organic Semiconductor Interfacial Area On The Performance Of Organic Transistors

We show that the performance of pentacene transistors can be significantly improved by maximizing the interfacial area at single walled carbon nanotube (SWCNT)/pentacene. The interfacial areas are varied by anchoring short SWCNTs of different densities (0–30/μm) to the Pd electrodes. The average mobility is increased three, six, and nine times for low, medium, and high SWCNT densities, respectively, compared to the devices with zero SWCNT. The current on-off ratio and on-current are increased up to 40 times and 20 times with increasing the SWCNT density. We explain the improved device performance using reduced barrier height of SWCNT/pentacene interface.
Automated Topical Component Extraction Using Neural Network Attention Scores from Source-based Essay Scoring

While automated essay scoring (AES) can reliably grade essays at scale, automated writing evaluation (AWE) additionally provides formative feedback to guide essay revision. However, a neural AES typically does not provide useful feature representations for supporting AWE. This paper presents a method for linking AWE and neural AES, by extracting Topical Components (TCs) representing evidence from a source text using the intermediate output of attention layers. We evaluate performance using a feature-based AES requiring TCs. Results show that performance is comparable whether using automatically or manually constructed TCs for 1) representing essays as rubric-based features, 2) grading essays.
A Dynamic-System-Based Approach to Modeling Driver Movements Across General-Purpose/Managed Lane Interfaces

Author(s): Wright, Matthew A.; Horowitz, Roberto; Kurzhanskiy, Alex A. | Abstract: To help mitigate road congestion caused by the unrelenting growth of traffic demand, many transportation authorities have implemented managed lane policies, which restrict certain freeway lanes to certain types of vehicles. It was originally thought that managed lanes would improve the use of existing infrastructure through demand-management behaviors like carpooling, but implementations have often been characterized by unpredicted phenomena that are sometimes detrimental to system performance. The development of traffic models that can capture these sorts of behaviors is a key step for helping managed lanes deliver on their promised gains. Towards this goal, this paper presents an approach for solving for driver behavior of entering and exiting managed lanes at the macroscopic (i.e., fluid approximation of traffic) scale. Our method is inspired by recent work in extending a dynamic-system-based modeling framework from traffic behaviors on individual roads, to models at junctions, and can be considered a further extension of this dynamic-system paradigm to the route/lane choice problem. Unlike traditional route choice models that are often based on discrete-choice methods and often rely on computing and comparing drivers' estimated travel times from taking different routes, our method is agnostic to the particular choice of physical traffic model and is suited specifically towards making decisions at these interfaces using only local information. These features make it a natural drop-in component to extend existing dynamic traffic modeling methods.
Nucleosynthesis of Nickel-56 from Gamma-Ray Burst Accretion Disks

We examine the prospects for producing nickel-56 from black hole accretion disks, by examining a range of steady-state disk models. We focus on relatively slowly accreting disks in the range of M ☉ s–1 to M ☉ s–1, as are thought to be appropriate for the central engines of long-duration gamma-ray bursts. We find that significant amounts of nickel-56 are produced over a wide range of parameter space. We discuss the influence of entropy, outflow timescale, and initial disk position on mass fraction of nickel-56 which is produced. We keep careful track of the weak interactions to ensure reliable calculations of the electron fraction, and discuss the role of the neutrinos.
Constraining Properties of Rapidly Rotating Neutron Stars Using Data from Heavy-Ion Collisions

Properties, structure, and thermal evolution of neutron stars are determined by the equation of state of stellar matter. Recent data on isospin diffusion and isoscaling in heavy-ion collisions at intermediate energies as well as data on the size of the neutron skin in 208Pb have considerably constrained the density dependence of the nuclear symmetry energy and, in turn, the equation of state of neutron-rich nucleonic matter. These constraints could provide useful information about the global properties of rapidly rotating neutron stars. Models of rapidly rotating neutron stars are constructed by applying several nucleonic equations of state. Particular emphasis is placed on configurations rotating rigidly at 716 and 1122 Hz. The range of allowed hydrostatic equilibrium solutions is determined and tested for stability. The effect of rotation on the internal composition and thermal properties of neutron stars is also examined. At a given rotational frequency, each equation of state yields a range of possible neutron stars configurations restricted by the Keplerian (mass-shedding) limit, corresponding to the maximal circumferential radius, and the limit due to the onset of instabilities with respect to axisymmetric perturbations, corresponding to the minimal equatorial radius of a stable neutron star model. We show that the mass of a neutron star rotating uniformly at 1122 Hz is between 1.7 and 2.1 M☉. Central stellar density and proton fraction decrease with increasing rotational frequency with respect to static models and, depending on the exact stellar mass and angular velocity, can drop below the direct Urca threshold, thus closing the fast cooling channel.
Prevention and Mitigation of Catastrophic Failures in Demand-Supply Interdependent Networks

We propose a generic system model for a special category of interdependent networks, demand-supply networks, in which the demand and the supply nodes are associated with heterogeneous loads and resources, respectively. Our model sheds a light on a unique cascading failure mechanism induced by resource/load fluctuations, which in turn opens the door to conducting stress analysis on interdependent networks. Compared to the existing literature mainly concerned with the node connectivity, we focus on developing effective resource allocation methods to prevent these cascading failures from happening and to mitigate/confine them upon occurrence in the network. To prevent cascading failures, we identify some dangerous stress mechanisms, based on which we quantify the robustness of the network in terms of the resource configuration scheme. Afterward, we identify the optimal resource configuration under two resource/load fluctuations scenarios: uniform and proportional fluctuations. We further investigate the optimal resource configuration problem considering heterogeneous resource sharing costs among the nodes. To mitigate/confine ongoing cascading failures, we propose two network adaptations mechanisms: intentional failure and resource re-adjustment , based on which we propose an algorithm to mitigate an ongoing cascading failure while reinforcing the surviving network with a high robustness to avoid further failures.
EMPIRICALLY DERIVED INTEGRATED STELLAR YIELDS OF Fe-PEAK ELEMENTS

We present here the initial results of a new study of massive star yields of Fe-peak elements. We have compiled from the literature a database of carefully determined solar neighborhood stellar abundances of seven iron-peak elements, Ti, V, Cr, Mn, Fe, Co, and Ni, and then plotted [X/Fe] versus [Fe/H] to study the trends as functions of metallicity. Chemical evolution models were then employed to force a fit to the observed trends by adjusting the input massive star metallicity-sensitive yields of Kobayashi et al. Our results suggest that yields of Ti, V, and Co are generally larger as well as anticorrelated with metallicity, in contrast to the Kobayashi et al. predictions. We also find the yields of Cr and Mn to be generally smaller and directly correlated with metallicity compared to the theoretical results. Our results for Ni are consistent with theory, although our model suggests that all Ni yields should be scaled up slightly. The outcome of this exercise is the computation of a set of integrated yields, i.e., stellar yields weighted by a slightly flattened time-independent Salpeter initial mass function and integrated over stellar mass, for each of the above elements at several metallicity points spanned by the broad range of observations. These results are designed to be used as empirical constraints on future iron-peak yield predictions by stellar evolution modelers. Special attention is paid to the interesting behavior of [Cr/Co] with metallicity—these two elements have opposite slopes—as well as the indirect correlation of [Ti/Fe] with [Fe/H]. These particular trends, as well as those exhibited by the inferred integrated yields of all iron-peak elements with metallicity, are discussed in terms of both supernova nucleosynthesis and atomic physics.
GalWeight: A New and Effective Weighting Technique for Determining Galaxy Cluster and Group Membership

We introduce GalWeight, a new technique for assigning galaxy cluster membership. This technique is specifically designed to simultaneously maximize the number of bona fide cluster members while minimizing the number of contaminating interlopers. The GalWeight technique can be applied to both massive galaxy clusters and poor galaxy groups. Moreover, it is effective in identifying members in both the virial and infall regions with high efficiency. We apply the GalWeight technique to MDPL2 \& Bolshoi N-body simulations, and find that it is $> 98\%$ accurate in correctly assigning cluster membership. We show that GalWeight compares very favorably against four well-known existing cluster membership techniques (shifting gapper, den Hartog, caustic, SIM). We also apply the GalWeight technique to a sample of twelve Abell clusters (including the Coma cluster) using observations from the Sloan Digital Sky Survey. We end by discussing GalWeight's potential for other astrophysical applications.
Signatures of a quantum Griffiths phase in a d-metal alloy close to its ferromagnetic quantum critical point

We report magnetization measurements close to the ferromagnetic quantum phase transition of the d-metal alloy Ni1 − xVx at a vanadium concentration of xc≈11.4%. In the diluted regime (x > xc), the temperature (T) and magnetic field (H) dependences of the magnetization are characterized by nonuniversal power laws and display H/T scaling in a wide temperature and field range. The exponents vary strongly with x and follow the predictions of a quantum Griffiths phase. We also discuss the deviations and limits of the quantum Griffiths phase as well as the phase boundaries due to bulk and cluster physics.
BERT-XML: Large Scale Automated ICD Coding Using BERT Pretraining

ICD coding is the task of classifying and cod-ing all diagnoses, symptoms and proceduresassociated with a patient’s visit. The process isoften manual, extremely time-consuming andexpensive for hospitals as clinical interactionsare usually recorded in free text medical notes.In this paper, we propose a machine learningmodel, BERT-XML, for large scale automatedICD coding of EHR notes, utilizing recentlydeveloped unsupervised pretraining that haveachieved state of the art performance on a va-riety of NLP tasks. We train a BERT modelfrom scratch on EHR notes, learning with vo-cabulary better suited for EHR tasks and thusoutperform off-the-shelf models. We furtheradapt the BERT architecture for ICD codingwith multi-label attention. We demonstratethe effectiveness of BERT-based models on thelarge scale ICD code classification task usingmillions of EHR notes to predict thousands ofunique codes.
Structures and magnetic properties of Co-Zr-B magnets studied by first-principles calculations

The structures and magnetic properties of Co-Zr-B alloys near the composition of Co5Zr with B at. % ≤6% were studied using adaptive genetic algorithm and first-principles calculations. The energy and magnetic moment contour maps as a function of chemical composition were constructed for the Co-Zr-B magnet alloys through extensive structure searches and calculations. We found that Co-Zr-B system exhibits the same structure motif as the “Co11Zr2” polymorphs, and such motif plays a key role in achieving strong magnetic anisotropy. Boron atoms were found to be able to substitute cobalt atoms or occupy the “interruption” sites. First-principles calculations showed that the magnetocrystalline anisotropy energies of the boron-doped alloys are close to that of the high-temperature rhombohedral Co5Zr phase and larger than that of the low-temperature Co5.25Zr phase. Our calculations provide useful guidelines for further experimental optimization of the magnetic performances of these alloys.
Isogenous components of Jacobian surfaces

Let be a genus 2 curve defined over a field K, $$\mathrm{char}\,K = p \geqslant 0$$ , and its Jacobian, where $$\iota $$ is the principal polarization of attached to . Assume that is (n, n)-geometrically reducible with $$E_1$$ and $$E_2$$ its elliptic components. We prove that there are only finitely many curves (up to isomorphism) defined over K such that $$E_1$$ and $$E_2$$ are N-isogenous for $$n=2$$ and $$N=2,3, 5, 7$$ with or $$n = 2$$ , $$N = 3,5, 7$$ with . The same holds if $$n=3$$ and $$N=5$$ . Furthermore, we determine the Kummer and Shioda–Inose surfaces for the above and show how such results in positive characteristic $$p>2$$ suggest nice applications in cryptography.
Tools for Identifying Spurious Luminosity Offsets in Tully-Fisher Studies: Application at Low Redshift and Implications for High Redshift

Studies of high-redshift galaxies usually interpret offsets from the Tully- Fisher (TF) relation as luminosity evolution. However, apparent luminosity offsets may actually reflect rotation curve anomalies such as strong asymmetries or radial truncation, due to galaxy interactions or low S/N data. Here we analyze emission-line rotation curves from two low-z samples: the Close Pairs Survey, which contains many interacting galaxies, and the Nearby Field Galaxy Survey (NFGS), which represents the general galaxy population. In the spirit of high-z samples, these surveys reflect the natural diversity of emission-line galaxies, including peculiar and early-type morphologies. We adopt objective criteria to identify severe kinematic anomalies. In the Close Pairs Survey, TF offsets associated with such anomalies collectively resemble the ``differential luminosity evolution'' claimed in some high-z studies, with larger offsets at lower luminosities. With anomalous galaxies rejected, however, the TF relations for the two surveys are quite similar. Furthermore, the two surveys follow similar relations between color and TF residuals, with the Pairs Survey relation extending to bluer colors and brighter TF residuals. Strong outliers from this relation are nearly always kinematically anomalous. Thus the color-TF residual relation can serve as a powerful tool for separating reliable luminosity offsets from offsets associated with kinematic anomalies. We reanalyze high-z TF data from the FORS Deep Field and find: (1) overall luminosity evolution of ~0.3 mag; (2) strong slope evolution driven by kinematically anomalous galaxies, which show TF offsets of up to ~2 mag at low luminosities; and (3) an additional zero-point offset of ~0.2 mag linked to anomalous galaxies.
A new measure of tension between experiments

Tensions between cosmological measurements by different surveys or probes have always been important —and are presently much discussed —as they may lead to evidence of new physics. Several tests have been devised to probe the consistency of datasets given a cosmological model, but they often have undesired features such as dependence on the prior volume, or burdensome requirements such as that of near-Gaussian posterior distributions. We propose a new quantity, defined in a similar way as the Bayesian evidence ratio, in which these undesired properties are absent. We test the quantity on simple models with Gaussian and non-Gaussian likelihoods. We then apply it to data from the Planck satellite: we investigate the consistency of ΛCDM model parameters obtained from TT and EE angular power spectrum measurements, as well as the mutual consistency of cosmological parameters obtained from large scale (multipoles, l<1000) and small scale (l ≥ 1000) portions of each measurement and find no significant discrepancy in the six-dimensional ΛCDM parameter space.
The $m=1$ Amplituhedron and Cyclic Hyperplane Arrangements

The (tree) amplituhedron A(n,k,m) is the image in the Grassmannian Gr(k,k+m) of the totally nonnegative part of Gr(k,n), under a (map induced by a) linear map which is totally positive. It was introduced by Arkani-Hamed and Trnka in 2013 in order to give a geometric basis for the computation of scattering amplitudes in N=4 supersymmetric Yang-Mills theory. When k+m=n, the amplituhedron is isomorphic to the totally nonnegative Grassmannian, and when k=1, the amplituhedron is a cyclic polytope. While the case m=4 is most relevant to physics, the amplituhedron is an interesting mathematical object for any m. In this paper we study it in the case m=1. We start by taking an orthogonal point of view and define a related "B-amplituhedron" B(n,k,m), which we show is isomorphic to A(n,k,m). We use this reformulation to describe the amplituhedron in terms of sign variation. We then give a cell decomposition of the amplituhedron A(n,k,1) using the images of a collection of distinguished cells of the totally nonnegative Grassmannian. We also show that A(n,k,1) can be identified with the complex of bounded faces of a cyclic hyperplane arrangement, and describe how its cells fit together. We deduce that A(n,k,1) is homeomorphic to a ball.
Far Ultraviolet Spectroscopic Explorer Observations of the Supernova Remnant N49 in the Large Magellanic Cloud

We report a Far Ultraviolet Spectroscopic Explorer satellite observation of the supernova remnant N49 in the Large Magellanic Cloud, covering the 905-1187 A spectral region. A 30'' square aperture was used, resulting in a velocity resolution of ~100 km s-1. The purpose of the observation was to examine several bright emission lines expected from earlier work and to demonstrate diffuse source sensitivity by searching for faint lines never seen previously in extragalactic supernova remnant UV spectra. Both goals were accomplished. Strong emission lines of O VI λλ1031.9, 1037.6 and C III λ977.0 were seen, Doppler broadened to ±225 km s-1 and with centroids redshifted to 350 km s-1, consistent with the LMC. Superposed on the emission lines are absorptions by C III and O VI λ1031.9 at +260 km s-1, which are attributed to warm and hot gas (respectively) in the LMC. The O VI λ1037.6 line is more severely affected by overlying interstellar and H2 absorption from both the LMC and our Galaxy. N III λ989.8 is not seen, but models indicate that overlying absorption severely attenuates this line. A number of faint lines from hot gas have also been detected, many of which have never been seen in an extragalactic supernova remnant spectrum.
BANYAN. XIII. A First Look at Nearby Young Associations with Gaia Data Release 2

In this paper we examine the nearest 100 pc entries in the data release 2 of Gaia to identify previously unrecognized candidate members in young associations. We analyze 695 952 stars with the BANYAN {\Sigma} Bayesian classification software and discover 898 new high-likelihood candidate members that span a wide range in properties, from spectral types B9 to L2, including 104 co-moving systems, 111 brown dwarfs and 31 new bona fide members. Our sample is mostly composed of highly active M dwarfs and will be crucial to examine the low-mass end of the initial mass function of young associations. Our sample includes new candidate members near the Galactic plane where previous surveys suffered from a high rate of contamination. This paper represents the first step towards a full reassessment of young associations in the Solar neighborhood with the second data release of the Gaia mission.
Weakly Supervised Cross-Lingual Named Entity Recognition via Effective Annotation and Representation Projection

The state-of-the-art named entity recognition (NER) systems are supervised machine learning models that require large amounts of manually annotated data to achieve high accuracy. However, annotating NER data by human is expensive and time-consuming, and can be quite difficult for a new language. In this paper, we present two weakly supervised approaches for cross-lingual NER with no human annotation in a target language. The first approach is to create automatically labeled NER data for a target language via annotation projection on comparable corpora, where we develop a heuristic scheme that effectively selects good-quality projection-labeled data from noisy data. The second approach is to project distributed representations of words (word embeddings) from a target language to a source language, so that the source-language NER system can be applied to the target language without re-training. We also design two co-decoding schemes that effectively combine the outputs of the two projection-based approaches. We evaluate the performance of the proposed approaches on both in-house and open NER data for several target languages. The results show that the combined systems outperform three other weakly supervised approaches on the CoNLL data.
Consistency of Perfect Fluidity and Jet Quenching in semi-Quark-Gluon Monopole Plasmas

We utilize a new framework, CUJET3.0, to deduce the energy and temperature dependence of the jet transport parameter, (E > 10 GeV, T), from a combined analysis of available data on nuclear modification factor and azimuthal asymmetries from high energy nuclear collisions at RHIC/BNL and LHC/CERN. Extending a previous perturbative-QCD based jet energy loss model (known as CUJET2.0) with (2+1)D viscous hydrodynamic bulk evolution, this new framework includes three novel features of nonperturbative physics origin: (i) the Polyakov loop suppression of color-electric scattering (aka 'semi-QGP' of Pisarski et al.), (ii) the enhancement of jet scattering due to emergent magnetic monopoles near Tc (aka 'magnetic scenario' of Liao and Shuryak), and (iii) thermodynamic properties constrained by lattice QCD data. CUJET3.0 reduces to v2.0 at high temperatures T >400 MeV, while greatly enhances near the QCD deconfinement transition temperature range. This enhancement accounts well for the observed elliptic harmonics of jets with pT > 10 GeV. Extrapolating our data-constrained down to thermal energy scales, E~2 GeV, we find for the first time a remarkable consistency between high energy jet quenching and bulk perfect fluidity with η/s ~ T3/ ~ 0.1 near Tc.
Effects of extrinsic point defects in phosphorene: B, C, N, O, and F adatoms

Phosphorene is emerging as a promising 2D semiconducting material with a direct band gap and high carrier mobility. In this paper, we examine the role of the extrinsic point defects including surface adatoms in modifying the electronic properties of phosphorene using density functional theory. The surface adatoms considered are B, C, N, O, and F with a [He] core electronic configuration. Our calculations show that B and C, with electronegativity close to P, prefer to break the sp3 bonds of phosphorene and reside at the interstitial sites in the 2D lattice by forming sp2 like bonds with the native atoms. On the other hand, N, O, and F, which are more electronegative than P, prefer the surface sites by attracting the lone pairs of phosphorene. B, N, and F adsorption will also introduce local magnetic moment to the lattice. Moreover, B, C, N, and F adatoms will modify the band gap of phosphorene, yielding metallic transverse tunneling characters. Oxygen does not modify the band gap of phosphorene, and a diod...
Applications and Challenges of Real-time Mobile DNA Analysis

The DNA sequencing is the process of identifying the exact order of nucleotides within a given DNA molecule. The new portable and relatively inexpensive DNA sequencers, such as Oxford Nanopore MinION, have the potential to move DNA sequencing outside of laboratory, leading to faster and more accessible DNA-based diagnostics. However, portable DNA sequencing and analysis are challenging for mobile systems, owing to high data throughput and computationally intensive processing performed in environments with unreliable connectivity and power. In this paper, we provide an analysis of the challenges that mobile systems must address to maximize the potential of portable DNA sequencing, and in situ DNA analysis. We explain the DNA sequencing process and highlight the main differences between traditional and portable DNA sequencing in the context of the actual and envisioned applications. We look at the identified challenges from the perspective of both algorithms and systems design, showing the need for careful co-design.
CHROMOSPHERIC AND CORONAL ACTIVITY IN THE 500 MYR OLD OPEN CLUSTER M37: EVIDENCE FOR CORONAL STRIPPING?

We present the results of a spectroscopic survey to characterize chromospheric activity, as measured by H$\alpha$ emission, in low-mass members of the 500-Myr-old open cluster M37. Combining our new measurements of H$\alpha$ luminosities ($L_{H\alpha}$) with previously cataloged stellar properties, we identify saturated and unsaturated regimes in the dependence of the $L_{H\alpha}$-to-bolometric-luminosity ratio, $L_{H\alpha}/L_{bol}$, on the Rossby number $R_o$. All rotators with Ro smaller than 0.03$\pm$0.01 converge to an activity level of $L_{H\alpha}/L_{bol}$ = (1.27$\pm$0.02) x 10$^{-4}$. This saturation threshold ($R_{o,sat}$ = 0.03$\pm$0.01) is statistically smaller than that found in most studies of the rotation-activity relation. In the unsaturated regime, slower rotators have lower levels of chromospheric activity, with $L_{H\alpha}/L_{bol}$($R_o$) following a power-law of index $\beta$ = -0.51$\pm$0.02, slightly shallower than the one found for a combined $\approx$650-Myr-old sample of Hyades and Praesepe stars. By comparing this unsaturated behavior to that previously found for coronal activity in M37 (as measured via the X-ray luminosity, $L_X$), we confirm that chromospheric activity decays at a much slower rate than coronal activity with increasing $R_o$. While a comparison of $L_{H\alpha}$ and $L_X$ for M37 members with measurements of both reveals a nearly 1:1 relation, removing the mass-dependencies by comparing instead $L_{H\alpha}/L_{bol}$ and $L_X/L_{bol}$ does not provide clear evidence for such a relation. Finally, we find that $R_{o,sat}$ is smaller for our chromospheric than for our coronal indicator of activity ($R_{o,sat}$ = 0.03$\pm$0.01 versus 0.09$\pm$0.01). We interpret this as possible evidence for coronal stripping.
CARBON, HELIUM, AND PROTON KINETIC TEMPERATURES IN A CYGNUS LOOP SHOCK WAVE

Observations of SN 1006 have shown that ions and electrons in the plasma behind fast supernova remnant shock waves are far from equilibrium, with the electron temperature much lower than the proton temperature and ion temperatures approximately proportional to ion mass. In the ∼360 km s−1shock waves of the Cygnus Loop, on the other hand, electron and ion temperatures are roughly equal, and there is evidence that the oxygen kinetic temperature is not far from the proton temperature. In this paper, we report observations of the He ii λ1640 line and the C iv λ1550 doublet in a 360 km s−1shock in the Cygnus Loop. While the best-fit kinetic temperatures are somewhat higher than the proton temperature, the temperatures of He and C are consistent with the proton temperature and the upper limits are 0.5 and 0.3 times the mass-proportional temperatures, implying efficient thermal equilibration in this collisionless shock. The equilibration of helium and hydrogen affects the conversion between proton temperatures determined from Hα line profiles and shock speeds, and the efficient equilibration found here reduces the shock speed estimates and the distance estimate to the Cygnus Loop of Medina et al. to about 800 pc.
Resolving New Keynesian Anomalies with Wealth in the Utility Function

At the zero lower bound, the New Keynesian model predicts that output and inflation collapse to implausibly low levels, and that government spending and forward guidance have implausibly large effects. To resolve these anomalies, we introduce wealth into the utility function; the justification is that wealth is a marker of social status, and people value status. Since people partly save to accrue social status, the Euler equation is modified. As a result, when the marginal utility of wealth is sufficiently large, the dynamical system representing the zero-lower-bound equilibrium transforms from a saddle to a source—which resolves all the anomalies.
Reconsidering Written Language

A number of elite thinkers in Europe during the 16th and 17th centuries pursued an agenda which historian Paolo Rossi calls the “quest for a universal language,” a quest which was deeply interwoven with the emergence of the scientific method. From a modern perspective, one of the many surprising aspects of these efforts is that they relied on a diverse array of memorization techniques as foundational elements. In the case of Leibniz’s universal calculus, the ultimate vision was to create a pictorial language that could be learned by anyone in a matter of weeks and which would contain within it a symbolic representation of all domains of contemporary thought, ranging from the natural sciences, to theology, to law. In this brief article, I explore why this agenda might have been appealing to thinkers of this era by examining ancient and modern memory feats. As a thought experiment, I suggest that a society built entirely upon memorization might be less limited than we might otherwise imagine, and furthermore, that cultural norms discouraging the use of written language might have had implications for the development of scientific methodology. Viewed in this light, the efforts of Leibniz and others seem significantly less surprising. I close with some general observations about cross-cultural origins of scientific thought.
Exact vs. semiclassical target space of the minimal string

We study both the classical and the quantum target space of (p,q) minimal string theory, using the FZZT brane as a probe. By thinking of the target space as the moduli space of FZZT branes, parametrized by the boundary cosmological constant x, we see that classically it consists of a Riemann surface p,q which is a p-sheeted cover of the complex x plane. However, we show using the dual matrix model that the exact quantum FZZT observables exhibit Stokes' phenomenon and are entire functions of x. Along the way we clarify some points about the semiclassical limit of D-brane correlation functions. The upshot is that nonperturbative effects modify the target space drastically, changing it from p,q to the complex x plane. To illustrate these ideas, we study in detail the example of (p,q) = (2,1), which is dual to the gaussian matrix model. Here we learn that the other sheets of the classical Riemann surface describe instantons in the effective theory on the brane. Finally, we discuss possible applications to black holes and the topological string.
Higher-twist corrections to gluon TMD factorization

We calculate power corrections to TMD factorization for particle production by gluon-gluon fusion in hadron-hadron collisions.
Forbidden line emission in the eccentric spectroscopic binaries DQ Tauri and UZ Tauri E monitored over an orbital period

We present echelle spectroscopy of the close pre–main-sequence binary star systems DQ Tau and UZ Tau E. Over a 16 day time interval we acquired 14 nights of spectra for DQ Tau and 12 nights of spectra for UZ Tau E. This represents the entire phase of DQ Tau and 63% of the phase of UZ Tau E. As expected, photospheric lines such as Li I λ6707 clearly split into two components while the primary and secondary orbit one another, as did the permitted line He I λ5876. Unlike the photospheric features, the forbidden lines of [O I] λ6300 and [O I] λ5577 retain the same shape throughout the orbit. Therefore, these lines must originate outside the immediate vicinity of the two stars and any circumstellar disks that participate in the orbital motion of the stars.
Detecting geometric splittings in finitely presented groups

We present an algorithm which given a presentation of a group $G$ without 2-torsion, a solution to the word problem with respect to this presentation, and an acylindricity constant ${\kappa}$, outputs a collection of tracks in an appropriate presentation complex. We give two applications: the first is an algorithm which decides if $G$ admits an essential free decomposition, the second is an algorithm which; if $G$ is relatively hyperbolic; decides if it admits an essential elementary splitting.
D-branes on orbifolds with discrete torsion and topological obstruction

We find the orbifold analog of the topological relation recently found by Freed and Witten which restricts the allowed D-brane configurations of type-II vacua with a topologically non-trivial flat B-field. The result relies in Douglas proposal - which we derive from worldsheet consistency conditions - of embedding projective representations on open string Chan-Paton factors when considering orbifolds with discrete torsion. The orbifold action on open strings gives a natural definition of the algebraic K-theory group - using twisted cross products - responsible for measuring Ramond-Ramond charges in orbifolds with discrete torsion. We show that the correspondence between fractional branes and Ramond-Ramond fields follows in an interesting fashion from the way that discrete torsion is implemented on open and closed strings.
Track-Assignment Detailed Routing Using Attention-based Policy Model With Supervision

Detailed routing is one of the most critical steps in analog circuit design. Complete routing has become increasingly more challenging in advanced node analog circuits, making advances in efficient automatic routers ever more necessary. In this work, we propose a machine learning driven method for solving the track-assignment detailed routing problem for advanced node analog circuits. Our approach adopts an attention-based reinforcement learning (RL) policy model. Our main insight and advancement over this RL model is the use of supervision as a way to leverage solutions generated by a conventional genetic algorithm (GA). For this, our approach minimizes the Kullback-Leibler divergence loss between the output from the RL policy model and a solution distribution obtained from the genetic solver. The key advantage of this approach is that the router can learn a policy in an offline setting with supervision, while improving the run-time performance nearly 100× over the genetic solver. Moreover, the quality of the solutions our approach produces matches well with those generated by GA. We show that especially for complex problems, our supervised RL method provides good quality solution similar to conventional attention-based RL without comprising run time performance. The ability to learn from example designs and train the router to get similar solutions with orders of magnitude run-time improvement can impact the design flow dramatically, potentially enabling increased design exploration and routability-driven placement.
Judicious QoS using cloud overlays

We revisit the long-standing problem of providing network QoS to applications, and propose the concept of judicious QoS - combining the cheaper, best effort IP service with the cloud, which offers a highly reliable infrastructure and the ability to add in-network services, albeit at higher cost. Our proposed J-QoS framework offers a range of reliability services with different cost vs. delay trade-offs, including: i) a forwarding service that forwards packets over the cloud overlay, ii) a caching service, which stores packets inside the cloud and allows them to be pulled in case of packet loss or disruption on the Internet, and iii) a novel coding service that provides the least expensive packet recovery option by combining packets of multiple application streams and sending a small number of coded packets across the more expensive cloud paths. We demonstrate the feasibility of these services using measurements from RIPE Atlas and a live deployment on PlanetLab. We also consider case studies on how J-QoS works with services up and down the network stack, including Skype video conferencing, TCP-based web transfers and cellular access networks.