cssi/SciSciGPT-SciSciNet huggingface dataset:
A Microfilament-eruption Mechanism for Solar Spicules

Recent investigations indicate that solar coronal jets result from eruptions of small-scale chromospheric filaments, called minifilaments; that is, the jets are produced by scaled-down versions of typical-sized filament eruptions. We consider whether solar spicules might in turn be scaled-down versions of coronal jets, being driven by eruptions of "microfilaments." Assuming a microfilament's size is about a spicule's width ($\sim$300~km), the estimated occurrence number plotted against the estimated size of erupting filaments, minifilaments, and microfilaments approximately follows a power-law distribution (based on counts of CMEs, coronal jets, and spicules), suggesting that many or most spicules could result from microfilament eruptions. Observed spicule-base Ca II brightenings plausibly result from such microfilament eruptions. By analogy with coronal jets, microfilament eruptions might produce spicules with many of their observed characteristics, including smooth rise profiles, twisting motions, and EUV counterparts. The postulated microfilament eruptions are presumably eruptions of twisted-core micro magnetic bipoles that are $\sim$1$".0$ wide. These explosive bipoles might be built and destabilized by merging and cancelation of magnetic-flux elements of $\sim$few$\times 100$~G and of size <~$0".5$---$1".0$. If however spicules are relatively more numerous than indicated by our extrapolated distribution, then only a fraction of spicules might result from this proposed mechanism.
Magnitude Gap Statistics and the Conditional Luminosity Function

In a recent preprint, Hearin et al. (H12) suggest that the halo mass-richness calibration of clusters can be improved by using the difference in the magnitude of the brightest and the second brightest galaxy (magnitude gap) as an additional observable. They claim that their results are at odds with the results from Paranjape & Sheth (PS12) who show that the magnitude distribution of the brightest and second brightest galaxies can be explained based on order statistics of luminosities randomly sampled from the total galaxy luminosity function. We find that a conditional luminosity function (CLF) for galaxies which varies with halo mass, in a manner which is consistent with existing observations, naturally leads to a magnitude gap distribution which changes as a function of halo mass at fixed richness, in qualitative agreement with H12. We show that, in general, the luminosity distribution of the brightest and the second brightest galaxy depends upon whether the luminosities of galaxies are drawn from the CLF or the global luminosity function. However, we also show that the difference between the two cases is small enough to evade detection in the small sample investigated by PS12. This shows that the luminosity distribution is not the appropriate statistic to distinguish between the two cases, given the small sample size. We argue in favor of the CLF (and therefore H12) based upon its consistency with other independent observations, such as the kinematics of satellite galaxies, the abundance and clustering of galaxies, and the galaxy-galaxy lensing signal from the Sloan Digital Sky Survey.
Total Mean Curvature, Scalar Curvature, and a Variational Analog of Brown–York Mass

We study the supremum of the total mean curvature on the boundary of compact, mean-convex 3-manifolds with nonnegative scalar curvature, and a prescribed boundary metric. We establish an additivity property for this supremum and exhibit rigidity for maximizers assuming the supremum is attained. When the boundary consists of 2-spheres, we demonstrate that the finiteness of the supremum follows from the previous work of Shi–Tam and Wang–Yau on the quasi-local mass problem in general relativity. In turn, we define a variational analog of Brown–York quasi-local mass without assuming that the boundary 2-sphere has positive Gauss curvature.
The Chemo-Dynamical History of the Milky Way as Revealed by SDSS/SEGUE

Although originally conceived as primarily an extragalactic survey, the Sloan Digital Sky Survey (SDSS-I), and its extensions SDSS-II and SDSS-III, continue to have a major impact on our understanding of the formation and evolution of our host galaxy, the Milky Way. The sub-survey SEGUE: Sloan Extension for Galactic Exploration and Understanding, excuted as part of SDSS-II, obtained some 3500 square degrees of additional ugriz imaging, mostly at lower Galactic latitudes, in order to better sample the disk systems of the Galaxy. Most importantly, it obtained over 240,000 medium-resolution spectra for stars selected to sample Galactocentric distances from 0.5 to 100 kpc. In combination with stellar targets from SDSS-I, and the recently completed SEGUE-2 program, executed as part of SDSS-III, the total sample of SDSS spectroscopy for Galactic stars comprises some 500,000 objects.The development of the SEGUE Stellar Parameter Pipeline has enabled the determination of accurate atmospheric parameter estimates for a large fraction of these stars. Many of the stars in this data set within 5 kpc of the Sun have sufficiently well-measured proper motions to determine their full space motions, permitting examination of the nature of much more distant populations represented by members that are presently passing through the solar neighborhood. Ongoing analyses of these data are being used to draw a much clearer picture of the nature of our galaxy, and to supply targets for detailed high-resolution spectrscopic follow-up with the world's largest telescopes. Here we discuss a few highlights of recently completed and ongoing investigations with these data.
Sinkhorn Barycenter via Functional Gradient Descent

In this paper, we consider the problem of computing the barycenter of a set of probability distributions under the Sinkhorn divergence. This problem has recently found applications across various domains, including graphics, learning, and vision, as it provides a meaningful mechanism to aggregate knowledge. Unlike previous approaches which directly operate in the space of probability measures, we recast the Sinkhorn barycenter problem as an instance of unconstrained functional optimization and develop a novel functional gradient descent method named Sinkhorn Descent (SD). We prove that SD converges to a stationary point at a sublinear rate, and under reasonable assumptions, we further show that it asymptotically finds a global minimizer of the Sinkhorn barycenter problem. Moreover, by providing a mean-field analysis, we show that SD preserves the weak convergence of empirical measures. Importantly, the computational complexity of SD scales linearly in the dimension $d$ and we demonstrate its scalability by solving a $100$-dimensional Sinkhorn barycenter problem.
Environmental sensing by wearable device for indoor activity and location estimation

We present results from a set of experiments in this pilot study to investigate the causal influence of user activity on various environmental parameters monitored by occupant-carried multi-purpose sensors. Hypotheses with respect to each type of measurements are verified, including temperature, humidity, and light level collected during eight typical activities: sitting in lab / cubicle, indoor walking / running, resting after physical activity, climbing stairs, taking elevators, and outdoor walking. Our main contribution is the development of features for activity and location recognition based on environmental measurements, which exploit location- and activity-specific characteristics and capture the trends resulted from the underlying physiological process. The features are statistically shown to have good separability and are also information-rich. Fusing environmental sensing together with acceleration is shown to achieve classification accuracy as high as 99.13%. For building applications, this study motivates a sensor fusion paradigm for learning individualized activity, location, and environmental preferences for energy management and user comfort.
Sparse and Functional Principal Components Analysis

Regularized variants of Principal Components Analysis, especially Sparse PCA and Functional PCA, are among the most useful tools for the analysis of complex high-dimensional data. Many examples of massive data, have both sparse and functional (smooth) aspects and may benefit from a regularization scheme that can capture both forms of structure. For example, in neuro-imaging data, the brain’s response to a stimulus may be restricted to a discrete region of activation (spatial sparsity), while exhibiting a smooth response within that region. We propose a unified approach to regularized PCA which can induce both sparsity and smoothness in both the row and column principal components. Our framework generalizes much of the previous literature, with sparse, functional, two-way sparse, and two-way functional PCA all being special cases of our approach. Our method permits flexible combinations of sparsity and smoothness that lead to improvements in feature selection and signal recovery, as well as more interpretable PCA factors. We demonstrate the efficacy of our method on simulated data and a neuroimaging example on EEG data.
Sharp Constants of Approximation Theory. II. Invariance Theorems and Certain Multivariate Inequalities of Different Metrics

We prove invariance theorems for general inequalities of different metrics and apply them to limit relations between the sharp constants in the multivariate Markov–Bernstein–Nikolskii type inequalities with the polyharmonic operator for algebraic polynomials on the unit sphere and the unit ball in $${\mathbb {R}}^m$$ and the corresponding constants for entire functions of spherical type on $${\mathbb {R}}^m$$. Certain relations in the univariate weighted spaces are discussed as well.
Absolute Dimensions of the Early F-type Eclipsing Binary V506 Ophiuchi

We report extensive differential V-band photometry and high-resolution spectroscopic observations of the early F-type, 1.06-day detached eclipsing binary V506 Oph. The observations, along with times of minimum light from the literature, are used to derive a very precise ephemeris and the physical properties for the components, with the absolute masses and radii being determined to 0.7% or better. The masses are 1.4153 ± 0.0100 M ☉ and 1.4023 ± 0.0094 M ☉ for the primary and secondary, the radii are 1.725 ± 0.010 R ☉ and 1.692 ± 0.012 R ☉, and the effective temperatures are 6840 ± 150 K and 6780 ± 110 K, respectively. The orbit is circular and the stars are rotating synchronously. The accuracy of the radii and temperatures is supported by the resulting distance estimate of 564 ± 30 pc, which is in excellent agreement with the value implied by the trigonometric parallax listed in the Gaia/Data Release 2 catalog. Current stellar evolution models from the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks series for a composition of [Fe/H] = −0.04 match the properties of both stars in V506 Oph very well at an age of 1.83 Gyr and indicate they are halfway through their core hydrogen-burning phase.
Determinant map for the prestack of Tate objects

We construct a map from the prestack of Tate objects over a commutative ring k to the stack of $${\mathbb {G}}_{\mathrm{m}}$$ -gerbes. The result is obtained by combining the determinant map from the stack of perfect complexes as proposed by Schurg–Toen–Vezzosi with a relative $$S_{\bullet }$$ -construction for Tate objects as studied by Braunling–Groechenig–Wolfson. Along the way we prove a result about the K-theory of vector bundles over a connective $${\mathbb {E}}_{\infty }$$ -ring spectrum which is possibly of independent interest.
Sound Speed Dependence of Alignment in Accretion Disks Subjected to Lense–Thirring Torques

We present a series of simulations in both pure hydrodynamics (HD) and magnetohydrodynamics (MHD) exploring the degree to which alignment of disks subjected to external precessional torques (e.g., as in the "Bardeen–Petterson" effect) is dependent upon the disk sound speed c s . Across the range of sound speeds examined, we find that the influence of the sound speed can be encapsulated in a simple "lumped-parameter" model proposed by Sorathia et al. In this model, alignment fronts propagate outward at a speed 0.2rΩprecess(r), where Ωprecess is the local test-particle precession frequency. Meanwhile, transonic radial motions transport angular momentum both inward and outward at a rate that can, in steady-state, be described roughly in terms of an orientation diffusion model with diffusion coefficient , for local orbital frequency Ω. The competition between the two leads, in isothermal disks, to a stationary position for the alignment front at a radius . For alignment to happen at all, the disk must either be turbulent due to the magnetorotational instability in MHD, or, in HD, it must be cool enough for the bending waves driven by disk warp to be nonlinear at their launch point. Contrary to long-standing predictions, warp dynamics in MHD disks appears to be independent of the ratio c s /(αv orb), for orbital speed v orb and ratio of stress to pressure α. In purely HD disks, i.e., those with no internal stresses other than bulk viscosity, warmer disks align weakly or not at all; cooler disks align qualitatively similarly to MHD disks.
Developing AlMn Films for Argonne TES Fabrication

The reference design for the next-generation cosmic microwave background (CMB) experiment, CMB-S4, relies on large arrays of transition-edge sensor (TES) bolometers coupled to Superconducting Quantum Interference Device (SQUID)-based readout systems. Mapping the CMB to near cosmic variance limits will enable the search for signatures of inflation and constrain dark energy and neutrino physics. AlMn TESes provide simple film manufacturing and highly uniform arrays over large areas to meet the requirements of the CMB-S4 experiment. TES parameters such as critical temperature and normal resistance must be tuned to experiment specifications and can be varied based on geometry and steps in the fabrication process such as deposition layering, geometry, and baking time and temperature. Using four-terminal sensing, we measured $$T_\mathrm{C}$$ and $$R_\mathrm{N}$$ of AlMn 2000 ppm films and devices of varying thicknesses fabricated at Argonne National Laboratory to motivate device geometries and fabrication processes to tune $$T_\mathrm{C}$$ to 150–200 mK and $$R_\mathrm{N}$$ to $$\sim $$10 m$$\Omega $$. Measurements of IV curves and time constants for the resulting devices of varying leg length were made using time-division SQUID multiplexing and determined $$T_\mathrm{C}$$, G, k, $$f_{3\,\mathrm{db}}$$, and $$R_\mathrm{N}$$. We present the results of these tests along with the geometries and fabrication steps used to tune the device parameters to the desired limits.
Comparing the Effects of DNS, DoT, and DoH on Web Performance

Nearly every service on the Internet relies on the Domain Name System (DNS), which translates a human-readable name to an IP address before two endpoints can communicate. Today, DNS traffic is unencrypted, leaving users vulnerable to eavesdropping and tampering. Past work has demonstrated that DNS queries can reveal a user’s browsing history and even what smart devices they are using at home. In response to these privacy concerns, two new protocols have been proposed: DNS-over-HTTPS (DoH) and DNS-over-TLS (DoT). Instead of sending DNS queries and responses in the clear, DoH and DoT establish encrypted connections between users and resolvers. By doing so, these protocols provide privacy and security guarantees that traditional DNS (Do53) lacks. In this paper, we measure the effect of Do53, DoT, and DoH on query response times and page load times from five global vantage points. We find that although DoH and DoT response times are generally higher than Do53, both protocols can perform better than Do53 in terms of page load times. However, as throughput decreases and substantial packet loss and latency are introduced, web pages load fastest with Do53. Additionally, web pages load successfully more often with Do53 and DoT than DoH. Based on these results, we provide several recommendations to improve DNS performance, such as opportunistic partial responses and wire format caching.
Low-energy effective field theory below the electroweak scale: operators and matching

The gauge-invariant operators up to dimension six in the low-energy effective field theory below the electroweak scale are classified. There are 70 Hermitian dimension-five and 3631 Hermitian dimension-six operators that conserve baryon and lepton number, as well as ΔB = ±ΔL = ±1, ΔL = ±2, and ΔL = ±4 operators. The matching onto these operators from the Standard Model Effective Field Theory (SMEFT) up to order 1/Λ2 is computed at tree level. SMEFT imposes constraints on the coefficients of the low-energy effective theory, which can be checked experimentally to determine whether the electroweak gauge symmetry is broken by a single fundamental scalar doublet as in SMEFT. Our results, when combined with the one-loop anomalous dimensions of the low-energy theory and the one-loop anomalous dimensions of SMEFT, allow one to compute the low-energy implications of new physics to leading-log accuracy, and combine them consistently with high-energy LHC constraints.
BayReL: Bayesian Relational Learning for Multi-omics Data Integration

High-throughput molecular profiling technologies have produced high-dimensional multi-omics data, enabling systematic understanding of living systems at the genome scale. Studying molecular interactions across different data types helps reveal signal transduction mechanisms across different classes of molecules. In this paper, we develop a novel Bayesian representation learning method that infers the relational interactions across multi-omics data types. Our method, Bayesian Relational Learning (BayReL) for multi-omics data integration, takes advantage of a priori known relationships among the same class of molecules, modeled as a graph at each corresponding view, to learn view-specific latent variables as well as a multi-partite graph that encodes the interactions across views. Our experiments on several real-world datasets demonstrate enhanced performance of BayReL in inferring meaningful interactions compared to existing baselines.
Symplectic embeddings of four-dimensional polydisks into balls

We obtain new obstructions to symplectic embeddings of the four-dimensional polydisk P ( a , 1 ) into the ball B ( c ) for 2 ≤ a ≤ ( 7 − 1 ) ∕ ( 7 − 2 ) ≈ 2 . 5 4 9 , extending work done by Hind and Lisi and by Hutchings. Schlenk’s folding construction permits us to conclude our bound on c is optimal. Our proof makes use of the combinatorial criterion necessary for one “convex toric domain” to symplectically embed into another introduced by Hutchings (2016). We also observe that the computational complexity of this criterion can be reduced from O ( 2 n ) to O ( n 2 ) .
Existence of compatible systems of lisse sheaves on arithmetic schemes

Deligne conjectured that a single l-adic lisse sheaf on a normal variety over a finite field can be embedded into a compatible system of l'-adic lisse sheaves with various l'. Drinfeld used Lafforgue's result as an input and proved this conjecture when the variety is smooth. We consider an analogous existence problem for a regular flat scheme over Z and prove some cases using Lafforgue's result and the work of Barnet-Lamb, Gee, Geraghty, and Taylor.
A sublinear version of Schur’s lemma and elliptic PDE

We study the weighted norm inequality of (1,q)-type, ∥ G ν ∥ L q ( Ω , d σ ) ≤ C ∥ ν ∥ for all ν ∈ ℳ + ( Ω ) , along with its weak-type analogue, for 0<q<1, where G is an integral operator associated with the nonnegative kernel G on Ω×Ω. Here ℳ+(Ω) denotes the class of positive Radon measures in Ω; σ,ν∈ℳ+(Ω), and ∥ν∥=ν(Ω). For both weak-type and strong-type inequalities, we provide conditions which characterize the measures σ for which such an embedding holds. The strong-type (1,q)-inequality for 0<q<1 is closely connected with existence of a positive function u such that u≥G(uqσ), i.e., a supersolution to the integral equation u − G ( u q σ ) = 0 , u ∈ L l o c q ( Ω , σ ) . This study is motivated by solving sublinear equations involving the fractional Laplacian, ( − Δ ) α 2 u − u q σ = 0 , in domains Ω⊆ℝn which have a positive Green function G for 0<α<n.
Analog Signal Compression and Multiplexing Techniques for Healthcare Internet of Things

Scalability is a major issue for Internet of Things (IoT) as the total amount of traffic data collected and/or the number of sensors deployed grow. In some IoT applications such as healthcare, power consumption is also a key design factor for the IoT devices. In this paper, a multi-signal compression and encoding method based on Analog Joint Source Channel Coding (AJSCC) is proposed that works fully in the analog domain without the need for power-hungry Analog-to-Digital Converters (ADCs). Compression is achieved by quantizing all the input signals but one. While saving power, this method can also reduce the number of devices by combining one or more sensing functionalities into a single device (called 'AJSCC device'). Apart from analog encoding, AJSCC devices communicate to an aggregator node (FPMM receiver) using a novel Frequency Position Modulation and Multiplexing (FPMM) technique. Such joint modulation and multiplexing technique presents three mayor advantages&#x2014;it is robust to interference at particular frequency bands, it protects against eavesdropping, and it consumes low power due to a very low Signal-to-Noise Ratio (SNR) operating region at the receiver. Performance of the proposed multi-signal compression method and FPMM technique is evaluated via simulations in terms of Mean Square Error (MSE) and Miss Detection Rate (MDR), respectively.
Particle Trapping in Axisymmetric Electron Holes

Electron orbits are calculated in solitary two-dimensional axisymmetric electrostatic potential structures, typical of plasma electron holes, in order to establish the conditions for the particles to remain trapped. Analytic calculations of the evolution of the parallel energy caused by the perturbing radial electric field are shown to agree well with full numerical orbit integration Poincare plots. The predominant mechanism of detrapping is resonance between the gyro frequency in the parallel magnetic field and harmonics of the parallel bounce frequency. A region of phase-space adjacent to the trapped-passing boundary in parallel energy is generally stochastic because of island overlap of different harmonics, but except for very strong radial electric field perturbation, more deeply trapped orbits have well-defined islands and are permanently confined. A simple universal quantitative algorithm is given, and its results plotted as a function of magnetic field strength and hole radial scale-length, determining the phase space volume available to sustain the electron hole by depression of the permanently trapped distribution function.
Review of reactor antineutrino experiments

As discussed elsewhere, the measurement of a non-zero value for θ13 would open up a wide range of possibilities to explore CP-violation and the mass hierarchy. Experimental methods to measure currently the unknown mixing angle θ13 include accelerator searches for the νe appearance and precise measurements of reactor antineutrino disappearance. The reactor antineutrino experiments are designed to search for a non-vanishing mixing angle θ13 with unprecedented sensitivity. This document describes current reactor antineutrino experiments and synergy between accelerator searches for the νe appearance and precise measurements of reactor antineutrino disappearance.
Incompressible Euler Equations and the Effect of Changes at a Distance

Because pressure is determined globally for the incompressible Euler equations, a localized change to the initial velocity will have an immediate effect throughout space. For solutions to be physically meaningful, one would expect such effects to decrease with distance from the localized change, giving the solutions a type of stability. Indeed, this is the case for solutions having spatial decay, as can be easily shown. We consider the more difficult case of solutions lacking spatial decay, and show that such stability still holds, albeit in a somewhat weaker form.
Temporal breakdown and Borel resummation in the complex Langevin method

Abstract We reexamine the Parisi–Klauder conjecture for complex e i θ / 2 ϕ 4 measures with a Wick rotation angle 0 ≤ θ / 2 ≤ π / 2 interpolating between Euclidean signature and Lorentzian signature. Our main result is that the asymptotics for short stochastic times t encapsulates information also about the equilibrium aspects. The moments evaluated with the complex measure and with the real measure defined by the stochastic Langevin equation have the same t → 0 asymptotic expansion which is shown to be Borel summable. The Borel transform correctly reproduces the time dependent moments of the complex measure for all t , including their t → ∞ equilibrium values. On the other hand the results of a direct numerical simulation of the Langevin moments are found to disagree from the ‘correct’ result for t larger than a finite t c . The breakdown time t c increases powerlike for decreasing strength of the noise’s imaginary part but cannot be excluded to be finite for purely real noise. To ascertain the discrepancy we also compute the real equilibrium distribution for complex noise explicitly and verify that its moments differ from those obtained with the complex measure.
The space of left orders of a group is either finite or uncountable

Let G be a group and let O_G denote the set of left orderings on G. Then O_G can be topologized in a natural way, and we shall study this topology to show that O_G can never be countably infinite. This paper retrieves correct parts of the withdrawn paper arXiv:math/0607470.
Covert Secret Key Generation With an Active Warden

We investigate the problem of covert and secret key generation over a state-dependent discrete memoryless channel with one-way public discussion in which an adversary, the warden, may arbitrarily choose the channel state. We develop an adaptive protocol that, under conditions that we explicitly specify, not only allows the transmitter and the legitimate receiver to exchange a secret key but also conceals from the active warden whether the protocol is being run. When specialized to passive adversaries that do not control the channel state, we partially characterize the covert secret key capacity. In particular, the covert secret key capacity is sometimes equal to the covert capacity of the channel, so that secrecy comes “for free.”
Irregular Riemann-Hilbert correspondence, Alekseev-Meinrenken dynamical r-matrices and Drinfeld twists

In 2004, Enriquez-Etingof-Marshall suggested a new approach to the Ginzburg-Weinstein linearization theorem for a quasitriangular Lie bialgebra $(\g,r)$. This approach is based on solving a system of PDEs for a gauge transformation between the classical r-matrix $r$ and the Alekseev-Meinrenken dynamical r-matrix. They proved that the semiclassical limit of an admissible Drinfeld twist gives rise to a solution of the PDEs. In this paper, we explain that preferred gauge transformations can be constructed as connection maps for a certain irregular Riemann-Hilbert problem (provided $r$ is the standard classical r-matrix). Along the way, we give a symplectic geometric interpretation of their PDEs, as a symplectic neighborhood version of the Ginzburg-Weinstein linearization theorem. Our construction is based on earlier works by Boalch. We then prove that for semisimple Lie algebra $\g$, any solution of the PDEs for the gauge transformation is the semiclassical limit of an admissible Drinfeld twist. As byproducts, we find a surprising relation between the connection maps and Drinfeld twists as well as a new description of the Lu-Weinstein symplectic double.
THE DIMENSIONLESS AGE OF THE UNIVERSE: A RIDDLE FOR OUR TIME

We present the interesting coincidence of cosmology and astrophysics that points toward a dimensionless age of the Universe H 0 t 0 that is close to one. Despite cosmic deceleration for 9 Gyr and acceleration since then, we find H 0 t 0 = 0.96 ± 0.01 for the ΛCDM model that fits SN Ia data from Pan-STARRS, CMB power spectra, and baryon acoustic oscillations. Similarly, astrophysical measures of stellar ages and the Hubble constant derived from redshifts and distances point to H 0 t ~ 1.0 ± 0.1. The wide range of possible values for H 0 t 0 realized during cosmic evolution means that we live at what appears to be a special time. This "synchronicity problem" is not precisely the same as the usual coincidence problem, because there are combinations of ΩM and ΩΛ for which the usual coincidence problem holds but for which H 0 t 0 is not close to 1.
Green's function Monte Carlo calculations of the electromagnetic and neutral-weak response functions in the quasi-elastic sector

A quantitative understanding of neutrino-nucleus interactions is demanded to achieve precise measurement of neutrino oscillations, and hence the determination of their masses. In addition, next generation detectors will be able to detect supernovae neutrinos, which are likely to shed some light on the open questions on the dynamics of core collapse. In this context, it is crucial to account for two-body meson-exchange currents along within realistic models of nuclear dynamics. We summarize our progresses towards the construction of a consistent framework, based on the Green’s function Monte Carlo method, that can be exploited to accurately describe neutrino interactions with atomic nuclei in the quasi-elastic sector.
Hausdorff dimension of three-period orbits in Birkhoff billiards

We prove that the Hausdorff dimension of the set of three-period orbits in classical billiards is at most one. Moreover, if the set of three-period orbits has Hausdorff dimension one, then it has a tangent line at almost every point.
Numerical Simulations of Gaseous Disks Generated from Collisional Cascades at the Roche Limits of White Dwarf Stars

We consider the long-term evolution of gaseous disks fed by the vaporization of small particles produced in a collisional cascade inside the Roche limit of a 0.6 Msun white dwarf. Adding solids with radius \r0\ at a constant rate $\dot{M}_0$ into a narrow annulus leads to two distinct types of evolution. When $\dot{M}_0 > \dot{M}_{0,crit}$ = $3 \times 10^4 ~ (r_0 / {\rm 1~km})^{3.92}$~g s$^{-1}$, the cascade generates a fairly steady accretion disk where the mass transfer rate of gas onto the white dwarf is roughly $\dot{M}_0$ and the mass in gas is $M_g \approx 2.3 \times 10^{22} ~ (\dot{M}_0 / 10^{10}~g~s^{-1}) ~ ({\rm 1500~K} / T_0) ~ (10^{-3} / \alpha)$~g, where $T_0$ is the temperature of the gas near the Roche limit and $\alpha$ is the dimensionless viscosity parameter. If $ \dot{M}_0 < \dot{M}_{0,crit}$, the system alternates between high states with large mass transfer rates and low states with negligible accretion. Although either mode of evolution adds significant amounts of metals to the white dwarf photosphere, none of our calculations yield a vertically thin ensemble of solids inside the Roche limit. X-ray observations can place limits on the mass transfer rate and test this model for metallic line white dwarfs.
PCA method for automated detection of mispronounced words

This paper presents a method for detecting mispronunciations with the aim of improving Computer Assisted Language Learning (CALL) tools used by foreign language learners. The algorithm is based on Principle Component Analysis (PCA). It is hierarchical with each successive step refining the estimate to classify the test word as being either mispronounced or correct. Preprocessing before detection, like normalization and time-scale modification, is implemented to guarantee uniformity of the feature vectors input to the detection system. The performance using various features including spectrograms and Mel-Frequency Cepstral Coefficients (MFCCs) are compared and evaluated. Best results were obtained using MFCCs, achieving up to 99% accuracy in word verification and 93% in native/non-native classification. Compared with Hidden Markov Models (HMMs) which are used pervasively in recognition application, this particular approach is computational efficient and effective when training data is limited.
The Media as a Source of Weight Stigma for Pregnant and Postpartum Women.

Objective The media often contain weight-stigmatizing material. However, little is known about pregnant and postpartum women's experiences with media-based weight stigma. Methods Two studies investigated weight stigma in the media from multiple perspectives. Study 1 analyzed open-response examples of weight-stigmatizing experiences coming from the media, broadly defined, from 123 pregnant and postpartum women (from a larger sample of 501). Study 2 identified online news-media articles about pregnancy and weight published during the study 1 data collection period (August to November 2017). Results Study 1 revealed that weight stigma was common and frequent in media, manifesting across three themes: (1) ideal appearance of pregnant bodies, (2) pressure to quickly "bounce back" after birth to a prepregnancy appearance, and (3) media praising celebrities for achieving either of the previous themes. Study 2 identified 33 articles. A content analysis revealed that women with overweight or obesity were rarely portrayed in images. Additionally, discussion of weight was often negative, focusing on adverse maternal-child health consequences. Finally, media-communicated ideals for weight and weight loss were often unrealistic and did not reference medical guidelines. Conclusions This work is the first to document that online news media are a pervasive and potentially distressing source of pregnancy-related weight stigma, suggesting much-needed reform in media guidelines.
Interactive Distributed Detection: Architecture and Performance Analysis

This paper studies the impact of interactive fusion on detection performance in tandem fusion networks with conditionally independent observations. Within the Neyman-Pearson framework, two distinct regimes are considered: the fixed sample size test and the large sample test. For the former, it is established that interactive distributed detection may strictly outperform the one-way tandem fusion structure. However, for the large sample regime, it is shown that interactive fusion has no improvement on the asymptotic performance characterized by the Kullback-Leibler (KL) distance compared with the simple one-way tandem fusion. The results are then extended to interactive fusion systems where the fusion center and the sensor may undergo multiple steps of memoryless interactions or that involve multiple peripheral sensors, as well as to interactive fusion with soft sensor outputs.
Obliquity Evolution of the Potentially Habitable Exoplanet Kepler-62f

Variations in the axial tilt, or obliquity, of terrestrial planets can affect their climates and therefore their habitability. Kepler-62f is a 1.4 R⊕ planet orbiting within the habitable zone of it...
The mixed problem in Lipschitz domains with general decompositions of the boundary

This paper continues the study of the mixed problem for the Laplacian. We consider a bounded Lipschitz domain Ω ⊂ Rn, n ≥ 2, with boundary that is decomposed as ∂Ω = D ∪ N , D and N disjoint. We let Λ denote the boundary of D (relative to ∂Ω) and impose conditions on the dimension and shape of Λ and the sets N and D. Under these geometric criteria, we show that there exists p0 > 1 depending on the domain Ω such that for p in the interval (1, p0), the mixed problem with Neumann data in the space Lp(N) and Dirichlet data in the Sobolev space W 1,p(D) has a unique solution with the non-tangential maximal function of the gradient of the solution in Lp(∂Ω). We also obtain results for p = 1 when the Dirichlet and Neumann data comes from Hardy spaces, and a result when the boundary data comes from weighted Sobolev spaces.
Dense Crystalline Dimer Packings of Regular Tetrahedra

We present the densest known packing of regular tetrahedra with density $\phi =\frac{4000}{4671}=0.856347\ldots\,$. Like the recently discovered packings of Kallus et al. and Torquato–Jiao, our packing is crystalline with a unit cell of four tetrahedra forming two triangular dipyramids (dimer clusters). We show that our packing has maximal density within a three-parameter family of dimer packings. Numerical compressions starting from random configurations suggest that the packing may be optimal at least for small cells with up to 16 tetrahedra and periodic boundaries.
Are Individuals Harmed by Gerrymandering? Examining Access to Congressional District Offices

Objective: We consider proximity and access to the district offices of members of Congress to explore whether gerrymandering affects individuals’ capacity to be heard and thus impairs their representation. Methods: In a study of six states, we conduct more than 123 million distance measurements to identify residents whose closest district office is in the wrong congressional district. Based on survey results, we then estimate the likelihood that such mismatched individuals will personally visit the office of their member of Congress. Results: We find that in five gerrymandered states between 28.7-47.5 percent of residents have a mismatched closest district office, a rate several times higher than in a non-gerrymandered state. Extrapolating from survey results, we find that mismatched residents are 38 percent less likely to visit their own district office, and that across five states gerrymandering effectively deters nearly 600,000 office visits over a two-year congressional session. Conclusion: Of significance in both the legal and scholarly arena, we find that gerrymandering increases the prevalence of mismatched district offices, thereby impeding constituents from making in-person visits that are widely viewed as the most effective mechanism for communicating their opinions and needs to Congress. We believe this heretofore undocumented mismatch warrants additional scholarly consideration of gerrymandering’s effects on individual’s access to tangible aspects of representation.
Directional Amplification with a Josephson Circuit

Amplification of weak signals in quantum information processing requires components that prevent return of noise through amplification chain. A directional amplifier based on the Josephson effect could overcome disadvantages of conventional isolators and allow components to be integrated on a chip.
Global Smooth Ion Dynamics in the Euler-Poisson System

A fundamental two-fluid model for describing dynamics of a plasma is the Euler-Poisson system, in which compressible ion and electron fluids interact with their self-consistent electrostatic force. Global smooth electron dynamics were constructed in Guo (Commun Math Phys 195:249–265, 1998) due to dispersive effect of the electric field. In this paper, we construct global smooth irrotational solutions with small amplitude for ion dynamics in the Euler-Poisson system.
Synchrotron emission from young and nearby pulsars

The rising cosmic ray positron fraction reported by the PAMELA collaboration has lead to a great deal of interest in astrophysical sources of energetic electrons and positrons, including pulsars. In this paper, we calculate the spectrum of synchrotron emission from electrons and positrons injected from 366 young pulsars ( < 106 years) contained in the ATNF catalog, and compare our results to observations. We find that if objects such as the Vela and Crab pulsars have injected ~ 1048 erg or more in energetic electrons and/or positrons, they are expected to produce bright and distinctive features in the synchrotron sky. Intriguingly, we predict hard synchrotron emission from these regions of the sky which is qualitatively similar to that observed by WMAP.
Flat Strips, Bowen-Margulis Measures, and Mixing of the Geodesic Flow for Rank One CAT(0) Spaces.

Let be a proper, geodesically complete CAT( ) space under a proper, non-elementary, isometric action by a group with a rank one element. We construct a generalized Bowen–Margulis measure on the space of unit-speed parametrized geodesics of modulo the -action. Although the construction of Bowen–Margulis measures for rank one non-positively curved manifolds and for CAT( ) spaces is well known, the construction for CAT( ) spaces hinges on establishing a new structural result of independent interest: almost no geodesic, under the Bowen–Margulis measure, bounds a flat strip of any positive width. We also show that almost every point in , under the Patterson–Sullivan measure, is isolated in the Tits metric. (For these results we assume the Bowen–Margulis measure is finite, as it is in the cocompact case.) Finally, we precisely characterize mixing when has full limit set: a finite Bowen–Margulis measure is not mixing under the geodesic flow precisely when is a tree with all edge lengths in for some . This characterization is new, even in the setting of CAT( ) spaces. More general (technical) versions of these results are also stated in the paper.
Introduction to the transverse spatial correlations in spontaneous parametric down-conversion through the biphoton birth zone

As a tutorial to the spatial aspects of spontaneous parametric downconversion (SPDC), we present a detailed first-principles derivation of the transverse correlation width of photon pairs in degenerate collinear SPDC. This width defines the size of a biphoton birth zone, the region where the signal and idler photons are likely to be found when conditioning on the position of the destroyed pump photon. Along the way, we discuss the quantum-optical calculation of the amplitude for the SPDC process, as well as its simplified form for nearly collinear degenerate phase matching. Following this, we show how this biphoton amplitude can be approximated with a double-Gaussian wavefunction, and give a brief discussion of the measurement statistics (and subsequent convenience) of such double-Gaussian wavefunctions. Next, we use this approximation to get a simplified estimation of the transverse correlation width, and compare it to more accurate calculations as well as experimental results. We then conclude with a discussion of the concept of a biphoton birth zone, using it to develop intuition for the tradeoff between the first-order spatial coherence and bipohoton correlations in SPDC.
Assessing the Intrinsic Uncertainty and Structural Stability of Planetary Models: 1. Parameterized Thermal‐Tectonic History Models

Thermal history models, that have been used to understand the geological history of Earth, are now being coupled to climate models to map conditions that allow planets to maintain surface water over geologic time - a criteria considered crucial for life. However, the lack of intrinsic uncertainty assessment has blurred guidelines for how thermal history models can be used toward this end. A model, as a representation of something real, is not expected to be complete. Unmodeled effects are assumed to be small enough that the model maintains utility for the issue(s) it was designed to address. The degree to which this holds depends on how unmodeled factors affect the certainty of model predictions. We quantify this intrinsic uncertainty for several parameterized thermal history models (a widely used subclass of planetary models). Single perturbation analysis is used to determine the reactance time of different models. This provides a metric for how long it takes low amplitude, unmodeled effects to decay or grow. Reactance time is shown to scale inversely with the strength of the dominant feedback (negative or positive) within a model. A perturbed physics analysis is then used to determine uncertainty shadows for model outputs. This provides probability distributions for model predictions and tests the structural stability of a model. That is, do model predictions remain qualitatively similar, and within assumed model limits, in the face of intrinsic uncertainty. Once intrinsic uncertainty is accounted for, model outputs/predictions and comparisons to observational data should be treated in a probabilistic way.
Intragroup and Intracluster Light

The largest stellar halos in the universe are found in massive galaxy clusters, where interactions and mergers of galaxies, along with the cluster tidal field, all act to strip stars from their host galaxies and feed the diffuse intracluster light (ICL) and extended halos of brightest cluster galaxies (BCGs). Studies of the nearby Virgo Cluster reveal a variety of accretion signatures imprinted in the morphology and stellar populations of its ICL. While simulations suggest the ICL should grow with time, attempts to track this evolution across clusters spanning a range of mass and redshift have proved difficult due to a variety of observational and definitional issues. Meanwhile, studies of nearby galaxy groups reveal the earliest stages of ICL formation: the extremely diffuse tidal streams formed during interactions in the group environment.
Directed Last Passage Percolation with Discontinuous Weights

We prove that a directed last passage percolation model with discontinuous macroscopic (non-random) inhomogeneities has a continuum limit that corresponds to solving a Hamilton–Jacobi equation in the viscosity sense. This Hamilton–Jacobi equation is closely related to the conservation law for the hydrodynamic limit of the totally asymmetric simple exclusion process. We also prove convergence of a numerical scheme for the Hamilton–Jacobi equation and present an algorithm based on dynamic programming for finding the asymptotic shapes of maximal directed paths.
Equity returns in the banking sector in the wake of the Great Recession and the European sovereign debt crisis

Abstract This study finds that equity returns in the banking sector in the wake of the Great Recession and the European sovereign debt crisis have been driven mainly by weak growth prospects and heightened sovereign risk; and to a lesser extent by deteriorating funding conditions and investor sentiment. While the equity return performance in the banking sector has been dismal in general, there is some evidence that better capitalized and less leveraged banks have outperformed their peers in times of stress.
On the Quasi-Three Dimensional Configuration of Magnetic Clouds.

We develop an optimization approach to model the magnetic field configuration of magnetic clouds, based on a linear force-free formulation in three dimensions. Such a solution, dubbed the Freidberg solution, is kin to the axisymmetric Lundquist solution, but with more general "helical symmetry." The merit of our approach is demonstrated via its application to two case studies of in situ measured magnetic clouds. Both yield results of reduced χ 2 ≈ 1. Case 1 shows a winding flux rope configuration with one major polarity. Case 2 exhibits a double-helix configuration with two flux bundles winding around each other and rooted on regions of mixed polarities. This study demonstrates the three-dimensional complexity of the magnetic cloud structures.
Differential electron yield imaging with STXM.

Abstract Total electron yield (TEY) imaging is an established scanning transmission X-ray microscopy (STXM) technique that gives varying contrast based on a sample’s geometry, elemental composition, and electrical conductivity. However, the TEY-STXM signal is determined solely by the electrons that the beam ejects from the sample. A related technique, X-ray beam-induced current (XBIC) imaging, is sensitive to electrons and holes independently, but requires electric fields in the sample. Here we report that multi-electrode devices can be wired to produce differential electron yield (DEY) contrast, which is also independently sensitive to electrons and holes, but does not require an electric field. Depending on whether the region illuminated by the focused STXM beam is better connected to one electrode or another, the DEY-STXM contrast changes sign. DEY-STXM images thus provide a vivid map of a device’s connectivity landscape, which can be key to understanding device function and failure. To demonstrate an application in the area of failure analysis, we image a 100 nm, lithographically-defined aluminum nanowire that has failed after being stressed with a large current density.