Miracle-dz/UniFAR-FTUs huggingface dataset:
On pseudosymmetric manifolds

In the literature, there are two different notions of pseudosymmetric manifolds, one by Chaki [7] and other by Deszcz [16], and there are many papers related to these notions. The object of the present paper is to deduce necessary and sufficient conditions for a Chaki pseudosymmetric [7] (resp. pseudo Ricci symmetric [8]) manifold to be Deszcz pseudosymmetric (resp. Ricci pseudosymmetric). We also study the necessary and sufficient conditions for a weakly symmetric [58] (resp. weakly Ricci symmetric [59]) manifold by Tam\'assy and Binh to be Deszcz pseudosymmetric (resp. Ricci pseudosymmetric). We also obtain the reduced form of the defining condition of weakly Ricci symmetric manifolds by Tam\'assy and Binh [59]. Finally we give some examples to show the independent existence of such types of pseudosymmetry which also ensure the existence of Roter type and generalized Roter type manifolds and the manifolds with recurrent curvature 2-form ([2], [29]) associated to various curvature tensors.
PULSAR J0453+1559: A DOUBLE NEUTRON STAR SYSTEM WITH A LARGE MASS ASYMMETRY

To understand the nature of supernovae and neutron star (NS) formation, as well as binary stellar evolution and their interactions, it is important to probe the distribution of NS masses. Until now, all double NS (DNS) systems have been measured as having a mass ratio close to unity (q ≥ 0.91). Here, we report the measurement of the individual masses of the 4.07-day binary pulsar J0453+1559 from measurements of the rate of advance of periastron and Shapiro delay: the mass of the pulsar is Mp = 1.559 ± 0.005 M⊙ and that of its companion is M c = 1.174 ± 0.004 ? > M⊙; q = 0.75. If this companion is also an NS, as indicated by the orbital eccentricity of the system (e = 0.11), then its mass is the smallest precisely measured for any such object. The pulsar has a spin period of 45.7 ms and a spin period derivative of P ˙ ? > = (1.8616±0.0007)×10−19 s s−1; from these, we derive a characteristic age of ∼ 4.1×109 years and a magnetic field of ∼ 2.9×109 G, i.e., this pulsar was mildly recycled by the accretion of matter from the progenitor of the companion star. This suggests that it was formed with (very approximately) its current mass. Thus, NSs form with a wide range of masses, which is important for understanding their formation in supernovae. It is also important for the search for gravitational waves released during an NS–NS merger: it is now evident that we should not assume that all DNS systems are symmetric.
Comments on “Stored Energies and Radiation Q”

The commented paper [1] claims to provide a new expression for an energy stored around a general radiator. The major purpose of this comment is to show that the claim is unjustified. Alongside with this issue, it is pointed out that some of the core formulas of [1] are not completely correct, and that their correct form has in fact been derived elsewhere, though for the purpose of evaluating the quality factor $Q_{Z}$ and not the stored energies.
Galaxy evolution from strong‐lensing statistics: the differential evolution of the velocity dispersion function in concord with the Λ cold dark matter paradigm

We study galaxy evolution from z = 1 to 0 as a function of velocity dispersion σ for galaxies with σ ≳ 95 km s -1 based on the measured and Monte Carlo realized local velocity dispersion functions (VDFs) of galaxies and the revised statistical properties of 30 strongly lensed sources from the Cosmic Lens All-Sky Survey, the PMN-NVSS Extragalactic Lens Survey and the Hubble Space Telescope Snapshot survey. We assume that the total (luminous plus dark) mass profile of a galaxy is isothermal in the optical region for 0 < z ≤ 1 as suggested by mass modelling of lensing galaxies. This study is the first to investigate the evolution of the VDF shape as well as the overall number density. It is also the first to study the evolution of the total and the late-type VDFs in addition to the early-type VDF. For the evolutionary behaviours of the VDFs, we find that: (1) the number density of massive (mostly early-type) galaxies with σ ≳ 200 km s -1 evolves differentially in the way that the number density evolution is greater at a higher velocity dispersion; (2) the number density of intermediate- and low-mass early-type galaxies (95 km s -1 ≲ σ ≲ 200 km s -1 ) is nearly constant and (3) the late-type VDF transformed from the Monte Carlo realized circular velocity function is consistent with no evolution in its shape or integrated number density consistent with galaxy survey results. These evolutionary behaviours of the VDFs are strikingly similar to those of the dark halo mass function (DMF) from N-body simulations and the stellar mass function (SMF) predicted by recent semi-analytic models of galaxy formation under the current A cold dark matter hierarchical structure formation paradigm. Interestingly, the VDF evolutions appear to be qualitatively different from 'stellar-mass-downsizing' evolutions obtained by many galaxy surveys. The co-evolution of the DMF, the VDF and the SMF is investigated in quantitative detail based on up-to-date theoretical and observational results in a following paper. We consider several possible systematic errors for the lensing analysis and find that they are not likely to alter the conclusions.
AN IMAGE-PLANE ALGORITHM FOR JWST'S NON-REDUNDANT APERTURE MASK DATA

The high angular resolution technique of non-redundant masking (NRM) or aperture masking interferometry (AMI) has yielded images of faint protoplanetary companions of nearby stars from the ground. AMI on James Webb Space Telescope (JWST)'s Near Infrared Imager and Slitless Spectrograph (NIRISS) has a lower thermal background than ground-based facilities and does not suffer from atmospheric instability. NIRISS AMI images are likely to have 90%–95% Strehl ratio between 2.77 and 4.8 μm. In this paper we quantify factors that limit the raw point source contrast of JWST NRM. We develop an analytic model of the NRM point spread function which includes different optical path delays (pistons) between mask holes and fit the model parameters with image plane data. It enables a straightforward way to exclude bad pixels, is suited to limited fields of view, and can incorporate effects such as intra-pixel sensitivity variations. We simulate various sources of noise to estimate their effect on the standard deviation of closure phase, σCP (a proxy for binary point source contrast). If σCP < 10−4 radians—a contrast ratio of 10 mag—young accreting gas giant planets (e.g., in the nearby Taurus star-forming region) could be imaged with JWST NIRISS. We show the feasibility of using NIRISS' NRM with the sub-Nyquist sampled F277W, which would enable some exoplanet chemistry characterization. In the presence of small piston errors, the dominant sources of closure phase error (depending on pixel sampling, and filter bandwidth) are flat field errors and unmodeled variations in intra-pixel sensitivity. The in-flight stability of NIRISS will determine how well these errors can be calibrated by observing a point source. Our results help develop efficient observing strategies for space-based NRM.
A classification of multipartite states by degree of non-locality

We propose a novel form of classification of multipartite states, in terms of the maximum degree of non-locality they can exhibit under any choice of local observables. This uses the hierarchy of notions previously introduced by Abramsky and Brandenburger: strong contextuality, logical contextuality, and probabilistic contextuality. We study n-qubit pure states. We conjecture that for more than 2 parties, all entangled states are logically contextual. We prove a number of results in support of this conjecture: (1) We show that all permutation-symmetric states are logically non-local. (2) We study the class of balanced states with functional dependencies. These states are described by Boolean functions and have a rich structure, allowing a detailed analysis, which again confirms the conjecture in this case.
An Introduction to Gravity Currents and Intrusions

Introduction Classification The Navier-Stokes equations Non-stratified ambient currents Shallow-water (SW) formulation for high-Re flows Motion of the interface and the continuity equation One-layer model A useful transformation The full behavior by numerical solution Dam-break stage Similarity solution The validity of the inviscid approximation The steady-state current and nose jump conditions Benjamin's analysis Jump condition Box models for 2D geometry Fixed volume current with inertial-buoyancy balance Inflow volume change Two-layer SW model Introduction The governing equations Boussinesq system in dimensionless form Jumps of interface for H < 2 Energy and work in a two-layer model Axisymmetric currents, SW formulation Governing equations A useful transformation The full behavior by numerical solution Dam-break stage Similarity solution The validity of the inviscid approximation Some comparisons Box models for axisymmetric geometry Fixed volume current with inertial-buoyancy balance Inflow volume change Effects of rotation Axisymmetric case Rotating channel Buoyancy decays: particle-driven, porous boundary, and entrainment Particle-driven currents Axisymmetric particle-driven current Extensions of particle-driven solutions Current over a porous bottom Axisymmetric current over a porous bottom Entrainment Non-Boussinesq systems Introduction Formulation Dam-break and initial slumping motion The transition and self-similar stages Summary Lubrication theory formulation for viscous currents 2D geometry Axisymmetric current Current in a porous medium II Stratified ambient currents and intrusions Continuous density transition Introduction The SW formulation SW results and comparisons with experiments and simulations Dam break Critical speed and nose-wave interaction Similarity solution The validity of the inviscid approximation Axisymmetric and rotating cases SW formulation SW and NS finite-difference results The validity of the inviscid approximation The steady-state current Steady-state flow pattern Results Comparisons and conclusions Intrusions in 2D geometry Introduction Two-layer stratification Linear transition layer Rectangular lock configurations Cylindrical lock in a fully linearly-stratified tank Similarity solution Non-symmetric intrusions Intrusions in axisymmetric geometry Introduction Two-layer stratification Fully linearly-stratified tank, part-depth locks Box models for 2D geometry Fixed volume and inertial-buoyancy balance S = 1, inflow volume change Box models for axisymmetric geometry Fixed volume and inertial-buoyancy balance S = 1, inflow volume change Lubrication theory for viscous currents with S = 1 2D geometry Axisymmetric geometry Energy Introduction 2D geometry Axisymmetric geometry SW equations: characteristics and finite-difference schemes Characteristics Numerical solution of the SW equations Navier-Stokes numerical simulations Formulation A finite-difference code Other codes Some useful formulas Leibniz's Theorem Vectors and coordinate systems
Analytic methods for cosmological likelihoods

We present general, analytic methods for cosmological likelihood analysis and solve the ‘many parameters’ problem in cosmology. Maxima are found by Newton’s method, while marginalization over nuisance parameters, and parameter errors and covariances are estimated by analytic marginalization of an arbitrary likelihood function, expanding the log-likelihood to second order, with flat or Gaussian priors. We show that information about remaining parameters is preserved by marginalization. Marginalizing over all parameters, we find an analytic expression for the Bayesian evidence for model selection. We apply these methods to data described by Gaussian likelihoods with parameters in the mean and covariance. These methods can speed up conventional likelihood analysis by orders of magnitude when combined with Markov chain Monte Carlo methods, while Bayesian model selection becomes effectively instantaneous.
Numerical Approximations to Extremal Toric Kähler Metrics with Arbitrary Kähler Class

Abstract We develop new algorithms for approximating extremal toric Kähler metrics. We focus on an extremal metric on , which is conformal to an Einstein metric (the Chen–LeBrun–Weber metric). We compare our approximation to one given by Bunch and Donaldson and compute various geometric quantities. In particular, we demonstrate a small eigenvalue of the scalar Laplacian of the Einstein metric that gives numerical evidence that the Einstein metric is conformally unstable under Ricci flow.
Effects of sapphire substrate orientation on Sn-doped α-Ga2O3 grown by halide vapor phase epitaxy using α-Cr2O3 buffers

Heavily Sn-doped films of α-Ga2O3 were grown by halide vapor phase epitaxy (HVPE) on basal plane c-sapphire and on (10-12) r-sapphire substrates with and without α-Cr2O3 thin buffers prepared by magnetron sputtering and annealing in air at 500 °C for 3 h. For both substrate orientations, the use of α-Cr2O3 buffers led to three major effects. The first was a substantial decrease of the half-width of the symmetric and asymmetric x-ray reflections. The second was an order of magnitude decrease of the net donor concentration produced by flowing the same amounts of Sn into the reactor. Third, there was a reduction in the concentration of the major electron trap in the films near E c − 1 eV by more than a factor of two. These results show the major influence of sapphire substrate orientation on the electrical and structural properties of α-Ga2O3 grown by HVPE.
A spectacular new species of Hyloscirtus (Anura: Hylidae) from the Cordillera de Los Llanganates in the eastern Andes of Ecuador

We have discovered a spectacular new species of frog in the genus Hyloscirtus, belonging to the H. larinopygion species group. The adult female is characterized by a mostly black body with large bright red spots on the dorsal and ventral surface, extremities, and toe pads. The adult male is unknown. Small juveniles are characterized by a yellow body with variable black markings on the flanks; while one larger juvenile displayed irregular orange or yellow marks on a black background color, with light orange or yellow toe pads. Additional distinctive external morphological features such as cloacal ornamentation are described, and some osteological details are imaged and analyzed. The performed phylogeny places the new species as the sister to a clade consisting of ten taxa, all of which are part of the H. larinopygion group. We use genetic distances to fit the new species into a published time-calibrated phylogeny of this group; our analysis based on the published chronology suggests that the divergence of the new species from its known congeners pre-dates the Quaternary period. The new species is currently only known only from Cerro Mayordomo, in Fundación EcoMinga´s Machay Reserve, at 2,900 m in the eastern Andes of Tungurahua province, Ecuador, near the southern edge of Los Llanganates National Park, but its real distribution may be larger.
Gauge Non-Invariant Higher-Spin Currents in $4d$ Minkowski Space

Conserved currents of any spin $t>0$ built from symmetric massless gauge fields of any integer spin $s \geq t$ in {4d} Minkowski space are found. In particular, stress-energy tensor for a higher-spin field of any spin is constructed. Analogously to spin-two stress (pseudo)tensor, currents considered in this paper are not gauge invariant. However, they are shown to generate gauge invariant conserved charges. Besides expected parity even HS currents, we found unexpected parity odd currents that generate less symmetries than the even ones. It is argued that these odd currents unlikely admit a consistent $AdS$ deformation.
Gravitational Magnification of Population III Supernovae in Hierarchical Cosmological Models: Next Generation Space Telescope Perspectives

We study the gravitational lensing magnification produced by the intervening cosmological matter distribution, as deduced from three different hierarchical models (standard cold dark matter [SCDM], lambda cold dark matter [LCDM], and cold + hot dark matter [CHDM]) of very high redshift sources, particularly supernovae in protogalactic (Population III) objects. By means of ray-shooting numerical simulations, we find that caustics are more intense and concentrated in SCDM models. The magnification probability function presents a moderate degree of evolution up to z ≈ 5 (CHDM) and z ≈ 7 (SCDM/LCDM). All models predict that statistically large magnifications of μ ≳ 20 are achievable with a probability of on the order of a fraction of percent, the SCDM model being the most efficient magnifier. All cosmologies predict that above z ≈ 4 there is a 10% chance to get magnifications larger than 3. We have explored the observational perspectives for Population III supernovae (SNe) detection with the Next Generation Space Telescope (NGST) when gravitational magnification is taken into account. We find that NGST should be able to detect and confirm spectroscopically Type II SNe up to a redshift of z ≈ 4 in the J band (for TSN = 25,000 K); this limit could be increased up to z ≈ 9 in the K band, allowing for a relatively moderate magnification. Possibly promising strategies for discriminating among cosmological models using their GL magnification predictions and very high-z SNe are sketched. Finally, we outline and discuss the limitations of our study.
Exact solution of the Fokker-Planck equation for isotropic scattering

An analytic solution for a Fokker-Planck equation that describes propagation of energetic particles through a scattering medium is obtained. The solution is found in terms of an infinite series of mixed moments of particle distribution. The spatial dispersion of a particle cloud released at t=0 evolves through three phases, ballistic (t >Tc), where Tc is the collision time.The ballistic phase is characterized by a decelerating expansion of the initial point source in form of a "box" distribution with thickening walls. The next, transdiffusive phase is marked by the box walls thickened to its size and a noticeable slow down of expansion. Finally, the evolution enters the conventional diffusion phase.
Dark-matter decay and the abundance of ultracompact minihalos

Ultracompact minihalos would be formed if there are larger density perturbations (0.0003 < δρ/ρ < 0.3) in the earlier epoch. Their density profile is steeper than the standard dark-matter halos. If dark matter can annihilate or decay into standard particles, e.g., photons, these objects would be the potential astrophysical sources. In order to be consistent with observations, as those from Fermi, the abundance of ultracompact minihalos must be constrained. On the other hand, the formation of these objects has very tight relation with the primordial curvature perturbations on smaller scale, so the fraction of ultracompact minihalos is very important for modern cosmology. In previous works, the studies are focused on the dark-matter annihilation for these objects. But if dark matter is not annihilated, the dark-matter decay is another important possible case. On the other hand, the abundance of ultracompact minihalos is related to many other parameters, such as the mass of dark matter, the decay channels and the density profile of dark-matter halos. One of the important aspects of this work is that we investigate the γ-ray signals from nearby ultracompact minihalos due to dark-matter decay and another important aspect is to study in detail how the different decay channels and density profiles affect the constraints on the abundance of ultracompact minihalos.
The Diagnostic Accuracy of Transabdominal and Transvaginal Color Doppler Ultrasound for Pregnant Women with Vasa Previa and Velamentous Cord Insertion

Objective The objective of this study is to evaluate feasibility and accuracy of transabdominal color Doppler ultrasound (TA-CDUS) and transvaginal color Doppler ultrasound (TV-CDUS) as screening methods for pregnant women with vasa previa (VP) and velamentous cord insertion (VCI). Methods A retrospective diagnostic accuracy study was performed on 5,434 pregnant women from 2018 to 2021, who underwent both TA-CDUS and TV-CDUS. Diagnostic performance of TA-CDUS and TV-CDUS was determined using specificity, positive predictive value (PPV), negative predictive value (NPV), accuracy, and positive and negative likelihood ratios (LR+ and LR−), using the delivery information (gross examination) as the “Gold-standard”. Patient records were reviewed for demographics and diagnosis. Results The combination of VP and VCI was diagnosed in 37/5434 (0.68%) women at delivery. The sensitivity, specificity, PPV, NPV, and overall test accuracy of TA-CDUS were 72.97%, 99.85%, 77.14%, 99.81%, and 99.67%, respectively, for diagnosing VP with VCI. The corresponding values for TV-CDUS were 89.19%, 99.87%, 82.50%, 99.93%, and 99.80%, respectively. Moreover, the sensitivity of combination of TA-CDUS and TA-CDUS in determining VP with VCI was 97.30%, specificity 99.98%, PPV 97.30%, NPV 99.98%, and accuracy 99.96%. No significant difference in the misdiagnosis and missed diagnosis was found between the examination by TA-CDUS and TV-CDUS. Conclusions Both TA-CDUS and TV-CDUS can be acceptable diagnostic tools for assessment of pregnant women with VP and VCI, with a better application of TV-CDUS with higher accuracy. The combination of TA-CDUS and TV-CDUS could provide an objective imaging basis for choosing clinical treatment strategies and predicting prognosis.
A state-of-the-art review of distribution-of-practice effects on L2 learning

The purpose of this state-of-the-art review is to provide a general overview of recent research on time distribution and second language (L2) learning with special implications for classroom settings. Several studies have been performed to examine how to best distribute the hours of L2 practice to maximize learning by comparing conditions that promote intensive exposure versus others in which L2 input or instruction is more widely spaced. Findings from these studies are relevant not only for practical purposes but also for theory development. This review provides a summary of recent studies as well as suggestions for pedagogical practice. Additionally, it identifies areas for future research concerning the effect of time distribution on L2 learning.
A SEARCH FOR BINARY ACTIVE GALACTIC NUCLEI: DOUBLE-PEAKED [O iii] AGNs IN THE SLOAN DIGITAL SKY SURVEY

We present active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS) having double-peaked profiles of [O iii]λλ5007, 4959 and other narrow emission lines, motivated by the prospect of finding candidate binary AGNs. These objects were identified by means of a visual examination of 21,592 quasars at z < 0.7 in SDSS Data Release 7 (DR7). Of the spectra with adequate signal-to-noise, 148 spectra exhibit a double-peaked [O iii] profile. Of these, 86 are Type 1 AGNs and 62 are Type 2 AGNs. Only two give the appearance of possibly being optically resolved double AGNs in the SDSS images, but many show close companions or signs of recent interaction. Radio-detected quasars are three times more likely to exhibit a double-peaked [O iii] profile than quasars with no detected radio flux, suggesting a role for jet interactions in producing the double-peaked profiles. Of the 66 broad-line (Type 1) AGNs that are undetected in the FIRST survey, 0.9% show double-peaked [O iii] profiles. We discuss statistical tests of the nature of the double-peaked objects. Further study is needed to determine which of them are binary AGNs rather than disturbed narrow line regions, and how many additional binaries may remain undetected because of insufficient line-of-sight velocity splitting. Previous studies indicate that 0.1% of SDSS quasars are spatially resolved binaries, with typical spacings of ∼10–100 kpc. If a substantial fraction of the double-peaked objects are indeed binaries, then our results imply that binaries occur more frequently at smaller separations (<10 kpc). This suggests that simultaneous fueling of both black holes is more common as the binary orbit decays through these spacings.