Miracle-dz/UniFAR-FTUs huggingface dataset:
Multicomponent radiatively driven stellar winds IV. On thehelium decoupling in the wind of sigma Ori E

We study the possibility of the helium decoupling in the stellar wind of sigma Ori E. To obtain reliable wind parameters for this star we first calculate NLTE wind model and derive wind mass-loss rate and terminal velocity. Using corresponding force multipliers we study the possibility of helium decoupling. We find that helium decoupling is not possible for realistic values of helium charge (calculated from NLTE wind models). Helium decoupling only seems possible for a very low helium charge. The reason for this behavior is the strong coupling between helium and hydrogen. We also find that frictional heating becomes important in the outer parts of the wind of sigma Ori E due to the collisions between some heavier elements and the passive components - hydrogen and helium. For a metallicity ten times lower than the solar one, both hydrogen and helium decouple from the metals and may fall back onto the stellar surface. However, this does not explain the observed chemical peculiarity since both these components decouple together from the absorbing ions. Although we do not include the effects of the magnetic field into our models, we argue that the presence of a magnetic field will likely not significantly modify the derived results because in such case model equations describe the motion parallel to the magnetic field.
Non-zero helicity extinction in light scattered from achiral (or chiral) small particles located at points of null incident helicity density

Based on a recent unified formulation on dichroism and extinction of helicity on scattering by a small particle, dipolar in the wide sense, magnetodielectric or not, chiral or achiral, we show that such extinction is enhanced not only at resonances of polarizabilities, but also due to interference between left and right circularly polarized components of the incident wave, which contributes with appropriate parameters of the illuminating field, even if the particle is achiral and is placed at points of the incident field at which the local incident helicity density is zero. This phenomenon goes beyond standard circular dichroism (CD), and we analyze it in detail on account of the values of several quantities involved in the process, both of the incident light and the particle. In addition, this interference produces a term in the helicity extinction that remarkably yields information on the real parts of the electric and/or magnetic polarizabilities, which are not provided by CD, and of which the helicity extinction phenomenon may be considered a generalization.
THE PAN-PACIFIC PLANET SEARCH. VI. GIANT PLANETS ORBITING HD 86950 AND HD 222076

We report the detection of two new planets orbiting the K giants HD 86950 and HD 222076, based on precise radial velocities obtained with three instruments: AAT/UCLES, FEROS, and CHIRON. HD 86950b has a period of 1270 ± 57 days at au, and m sin . HD 222076b has days at au, and m sin . These two giant planets are typical of the population of planets known to orbit evolved stars. In addition, we find a high-amplitude periodic velocity signal ( m s−1) in HD 29399 and show that it is due to stellar variability rather than Keplerian reflex motion. We also investigate the relation between planet occurrence and host-star metallicity for the 164-star Pan-Pacific Planet Search (PPPS) sample of evolved stars. In spite of the small sample of PPPS detections, we confirm the trend of increasing planet occurrence as a function of metallicity found by other studies of planets orbiting evolved stars.
An Equivariant Sphere Theorem

Let M be a connected 3-manifold acted on by a group G. Suppose M has a triangulation invariant under G. In this paper it is shown that if there exists an embedded 2-sphere S which does not bound a 3-ball, then there exists such an S for which gS = S or gS 0 S = 0 for every g e G. This result was proved by Meeks, Simon and Yau [3] using analytic techniques. The proof given here is self-contained and elementary. The proof involves looking at embedded 2-spheres which are in general position with respect to the given triangulation. Such a sphere is called minimal if it does not bound a 3-ball and the number of intersections with the 1-skeleton of the triangulation is the smallest possible. The key result proved in this paper is that given a finite set of minimal spheres satisfying a general position condition, there is a finite set of 'standard' disjoint minimal spheres whose union has the same intersection with the 1-skeleton as the original spheres. The set of disjoint spheres is unique up to a homeomorphism of M which fixes the 2-skeleton. In §4 it is shown that if G\K is finite then there is a G-equivariant decomposition of M with irreducible factors. We are then able to deduce from the ordinary loop theorem an equivariant version of the projective plane theorem. In §5 the arguments of the previous sections are modified to provide a proof of the equivariant loop theorem [2]. I think that many of the topological results obtained using analytic minimal surface theory can also be derived using the techniques of this paper. I am grateful to Andrew Bartholomew for pointing out an error in an earlier version of this paper. I thank both Peter Scott and the referee for their helpful comments.
Concentrating small particles in protoplanetary disks through the streaming instability

Laboratory experiments indicate that direct growth of silicate grains via mutual collisions can only produce particles up to roughly millimeters in size. On the other hand, recent simulations of the streaming instability have shown that mm/cm-sized particles require an excessively high metallicity for dense filaments to emerge. Using the numerical algorithm of Yang & Johansen (2016) for stiff mutual drag force, we revisit the investigations of Carrera et al. (2015) and perform simulations of small particles with significantly higher resolutions and longer simulation times. We find that particles of dimensionless stopping time $\tau_\mathrm{s} = 10^{-2}$ and $10^{-3}$ -- representing mm- and cm-sized particles interior of the water ice line -- concentrate themselves via the streaming instability at a solid abundance of a few percent. We thus revise the critical solid abundance curve of Carrera et al. (2015) for the regime of $\tau_\mathrm{s} \ll 1$. The solid density in the concentrated regions reaches values higher than the Roche density, indicating that gravitational contraction into planetesimals is possible. Our results hence bridge the gap in particle size between direct dust growth limited by bouncing and the streaming instability.
In-Hospital Symptoms of Depression and Anxiety are Strong Risk Factors for Post-Stroke Depression 90 Days After Ischemic Stroke

Background and Purpose Acute ischemic stroke (AIS) and depression are the major causes of disability and decreased quality of life worldwide. Psychiatric disorders are common after stroke, especially post-stroke depression (PSD), which affects one-third of survivors. Although frequent, little is known about the real complexity of the pathophysiology and the factors associated with PSD. Methods This research aimed to provide data about risk factors and predictors of PSD 90 days after AIS. A cohort study was conducted in a tertiary stroke center located in southern Brazil. We interviewed 148 patients with AIS who were consecutively hospitalized between January 2020 and January 2021. The Hospital Anxiety and Depression Scale (HADS) was applied during hospitalization and at follow-up 90 days after AIS. Furthermore, sociodemographic, clinical, and radiological variables were investigated. Predictive factors were assessed using univariate and multivariate linear regression. The impact of the COVID-19 pandemic on the data was also evaluated. Results The frequency of PSD 90 days after AIS was 33.9%. In-hospital symptoms of depression and anxiety each represented a 2-fold risk for PSD at follow-up. Furthermore, the HADS – anxiety score 90 days after AIS was strongly associated with the HADS – depression value 90 days after stroke (R: .71; B: .56; P < .01). Conclusions The present study highlighted a noteworthy frequency of PSD 90 days after AIS. Psychiatric variables during hospitalization and in the follow-up appeared to be the leading associated factors with PSD. These data might support the determination of which patients require more psychiatric management.
A Novel Study: GAN-Based Minority Class Balancing and Machine-Learning-Based Network Intruder Detection Using Chi-Square Feature Selection

The network security problem becomes a routine problem for networks and cyber security specialists. The increased data on every minute not only creates big data problems, but also it expands the network size on the cloud and other computing technologies. Due to the big size and data, the network becomes more vulnerable to cyber-attacks. However, the detection of cyber-attacks on networks before or on time is a challenging task to solve. Therefore, the network intruder detection system (NIDS) is used to detect it. The network provided data-based NIDS were proposed previously, but still needed improvements. From the network data, it is also essential to find the most contributing features to avoid overfitting and lack of confidence in NIDS. The previously proposed solutions of NIDS mostly ignored the class imbalance problems that were normally found in the training of machine learning (ML) methods used in NIDS. However, few studies have tried to solve class imbalance and feature selection separately by achieving significant results on different datasets. The performance of these NIDS needs improvements in terms of classification and class balancing robust solutions. Therefore, to solve the class imbalance problem of minority classes in public datasets of NIDS and to select the most significant features, the proposed study gives a framework. In this framework, the minority class instances are generated using Generative Adversarial Network (GAN) model hyperparameter optimization and then the chi-square method of feature selection is applied to the fed six ML classifiers. The binary and multi-class classifications are applied on the UNSW-NB15 dataset with three versions of it. The comparative analysis on binary, multi-class classifications showed dominance as compared to previous studies in terms of accuracy (98.14%, 87.44%), precision (98.14%, 87.81%), F1-score (98.14%, 86.79%), Geometric-Mean (0.976, 0.923) and Area Under Cover (0.976, 0.94).
A generalisation of Niessen's limit-circle criterion

Synopsis Let S and T be formally symmetric ordinary differential operators defined on a real interval I. It is assumed that the order of S is constant and everywhere strictly higher than the possibly varying order of T. The main result of this paper (Theorem 2.3) gives necessary and sufficient conditions for maximality of the deficiency indices of the differential relation Su = Tv considered in a Hilbert space with a scalar product which is a Dirichlet integral (see section 2) belonging to S. The conditions generalise those given in [5] for less general choices of operators S and T. For certain choices of Dirichlet integral they are explicit integrability conditions on the coefficients of the Dirichlet integral and the operator T.
Robust Nonlinear Model Predictive Control for Ship Dynamic Positioning Using Laguerre Function

This paper is devoted to the issue of computationally efficient and robust nonlinear model predictive control (NMPC) for ship dynamic positioning (DP) systems subjected to input constraints and unknown environmental disturbances. The Laguerre functions, typically applied to the linear systems, are introduced to the constrained NMPC design of the nonlinear DP system to reduce the computational burden. The unscented Kalman filter is adopted to estimate the unknown disturbances and states; thus, the disturbance estimates are utilized as the cancellation signal to achieve robust offset-free control. Simulations of the proposed Laguerre function-based NMPC scheme are implemented and compared with the performance of typical Laguerre function-based linear model predictive control (LMPC) for the DP system. Simulation results well demonstrate the effectiveness, robustness and superiority of the proposed controller.
Influences of Superficial Si Layer Thickness on Band-to-Band Tunneling Current Characteristics in Ultra-Thin n-Channel Metal-Oxide-Semiconductor Field-Effect-Transistor by Separation by IMplanted OXygen (nMOSFET/SIMOX)

The band-to-band tunneling current characteristics of buried-channel nMOSFETs/SIMOX are investigated. It is shown that the drain current due to band-to-band tunneling current increases with decreasing superficial Si layer thickness. Two-dimensional device simulation results indicate that the decrease in superficial Si layer thickness leads to an increase in surface electric field in the gate-overlapped drain region. The device simulation results also suggest that the doping profile in the diffusion region affects the surface electric field moderately. The expression of surface electric field is improved to include the terms that depend on Si layer thickness and diffusion profile. This improved expression results in a quantitative coincidence between calculation and experimental results.
Mapping Distances across the Perseus Molecular Cloud Using CO Observations, Stellar Photometry, and Gaia DR2 Parallax Measurements

We present a new technique to determine distances to major star-forming regions across the Perseus Molecular Cloud, using a combination of stellar photometry, astrometric data, and 12CO spectral-line maps. Incorporating the Gaia DR2 parallax measurements when available, we start by inferring the distance and reddening to stars from their Pan-STARRS1 and Two Micron All Sky Survey photometry, based on a technique presented by Green et al. and implemented in their 3D “Bayestar” dust map of three-quarters of the sky. We then refine their technique by using the velocity slices of a CO spectral cube as dust templates and modeling the cumulative distribution of dust along the line of sight toward these stars as a linear combination of the emission in the slices. Using a nested sampling algorithm, we fit these per-star distance–reddening measurements to find the distances to the CO velocity slices toward each star-forming region. This results in distance estimates explicitly tied to the velocity structure of the molecular gas. We determine distances to the B5, IC 348, B1, NGC 1333, L1448, and L1451 star-forming regions and find that individual clouds are located between ≈275 and 300 pc, with typical combined uncertainties of ≈5%. We find that the velocity gradient across Perseus corresponds to a distance gradient of about 25 pc, with the eastern portion of the cloud farther away than the western portion. We determine an average distance to the complex of 294 ± 17 pc, about 60 pc further than the distance derived to the western portion of the cloud using parallax measurements of water masers associated with young stellar objects. The method we present is not limited to the Perseus Complex, but may be applied anywhere on the sky with adequate CO data in the pursuit of more accurate 3D maps of molecular clouds in the solar neighborhood and beyond.
Particle size segregation in inclined chute flow of dry cohesionless granular solids

If granular materials comprising particles of identical material but different sizes are sheared in the presence of a gravitational field, the particles are segregated according to size. The small particles fall to the bottom and the larger ones drift to the top of the sheared layer. In an attempt to isolate and study some of the essential segregation mechanisms, the paper considers a simplified problem involving the steady two-dimensional flow of a binary mixture of small and large spherical particles flowing down a roughened inclined chute. The flow is assumed to take place in layers that are in motion relative to one another as a result of the mean shear. For relatively slow flows, it is proposed that there are two main mechanisms responsible for the transfer of particles between layers. The first mechanism, termed the ‘random fluctuating sieve’, is a gravity-induced, size-dependent, void-filling mechanism. The probability of capture of a particle in one layer by a randomly generated void space in the underlying layer is calculated as a function of the relative motion of the two layers. The second, termed the ‘squeeze expulsion’ mechanism, is due to imbalances in contact forces on an individual particle which squeeze it out of its own layer into an adjacent one. It is assumed that this mechanism is not size preferential and that there is no inherent preferential direction for the layer transfer. This second physical mechanism in particular was proposed on the basis of observations of video recordings that were played back at slow speed. Since the magnitude of its contribution is determined by the satisfaction of overall mass conservation, the exact physical nature of the mechanism is of less importance. By combining these two proposed mechanisms the net percolation velocity of each species is obtained. The mass conservation equation for fines is solved by the method of characteristics to obtain the development of concentration profiles with downstream distance. Although the theory involves a number of empirical constants, their magnitude can be estimated with a fair degree of accuracy. A solution for the limiting case of dilute concentration of fine particles and a more general solution for arbitrary concentrations are presented. The analyses are compared with experiments which measured the development of concentration profiles during the flow of a binary mixture of coarse and fine particles down a roughened inclined chute. Reasonable agreement is found between the measured and predicted concentration profiles and the distance required for the complete separation of fine from coarse particles.
A note on Drazin inverses

REMARKS. (1) It is well known and easy to prove that T is a generalized Fredholm operator if and only if it has a generalized inverse. Some properties of the operator thus defined are obtained in [1] but generally there remain unsatisfactory features. For example, in Banach space there is no obvious way of defining a unique generalized inverse and there is no useful relation between the spectrum of an operator and of any of its generalized inverse. (2) The Drazin inverse was introduced in [2] in a very general context and avoids the two defects mentioned above. Note also that if the index is equal to 1, then D is a generalized inverse of T.
DISTRIBUTIONS OF LEAST SQUARES ESTIMATORS OF AUTOREGRESSIVE PARAMETERS FOR A PROCESS WITH COMPLEX ROOTS ON THE UNIT CIRCLE

Asymptotic distributions of the autoregressive parameters in the AR(2) model are derived, when the characteristic polynomial has a pair of complex roots on the unit circle. Percentage points are tabulated based on simulations from the asymptotic formulae. The usefulness of the asymptotic results in finite sample situations is investigated by a Monte Carlo study, and an illustrative example is given.
Preferential attachment growth model and nonextensive statistical mechanics

We introduce a two-dimensional growth model where every new site is located, at a distance r from the barycenter of the pre-existing graph, according to the probability law 1/r2 + αG (αG > 0), and is attached to (only) one pre-existing site with a probability ∝ ki/riαA (αA ⩾ 0; ki is the number of links of the i-th site of the pre-existing graph, and ri its distance to the new site). Then we numerically determine that the probability distribution for a site to have k links is asymptotically given, for all values of αG, by P(k) ∝ eq−k/κ, where eqx ≡ [1 + (1 − q)x]1/(1 − q) is the function naturally emerging within nonextensive statistical mechanics. The entropic index is numerically given (at least for αA not too large) by q = 1 + (1/3)e−0.526 αA, and the characteristic number of links by κ ≃ 0.1 + 0.08 αA. The αA = 0 particular case belongs to the same universality class to which the Barabasi-Albert model belongs. In addition to this, we have numerically studied the rate at which the average number of links ⟨ki⟩ increases with the scaled time t/i; asymptotically, ⟨ki⟩ ∝ (t/i)β, the exponent being close to β = ½(1 − αA) for 0 ⩽ αA ⩽ 1, and zero otherwise. The present results reinforce the conjecture that the microscopic dynamics of nonextensive systems typically build (for instance, in Gibbs Γ-space for Hamiltonian systems) a scale-free network.
New N = 4 supersymmetric Yang-Mills path integral

Using Lorentz-covariant spinor helicity formalism, we reorganize the unitary scalar superfield light-cone path integral for the N = 4 supersymmetric Yang-Mills theory. In new variables in the chiral Fourier superspace, the quadratic and cubic parts of the classical action have manifest Lorentz, kinematical and dynamical supersymmetry, with the exception of terms which contribute only to the contact terms in the supergraphs with propagators shrinking to a point. These terms have the same structure as supergraphs with quartic light-cone vertices, which break dynamical supersymmetry. We present evidence that all complicated terms breaking dynamical supersymmetry have to cancel and therefore can be omitted. It is plausible that the new form of the path integral leads to a set of relatively simple unitarity based rules with manifest N = 4 supersymmetry.
Measurement method for the nuclear anapole moment of laser trapped alkali atoms

Weak interactions within a nucleus generate a nuclear spin dependent parity violating electromagnetic moment; the anapole moment. In heavy nuclei, the anapole moment is the dominant contribution to spin-dependent atomic parity violation. We analyze a method to measure the nuclear anapole moment through the electric dipole transition it induces between hyperfine states of the ground level. The method requires tight confinement of the atoms to position them at the anti-node of a standing wave driving the anapole-induced E1 transiton. We explore the necessary limits in the number of atoms, excitation fields, trap type, interrogation method, and systematic tests necessary for such measurements in francium, the heaviest alkali.
InGaN/GaN/AlGaN-Based Laser Diodes with Modulation-Doped Strained-Layer Superlattices

InGaN multi-quantum-well-structure laser diodes with Al0.14Ga0. 86N/GaN modulation doped strained-layer superlattice cladding layers grown on an epitaxially laterally overgrown GaN substrate were demonstrated to have an estimated lifetime of more than 10000 h under continuous-wave operation at 20° C. Under operation at a high temperature of 50° C, the lifetime was longer than 1000 h. With the operating current increasing to above the threshold, a self-pulsation with a high frequency of 3.5 GHz was observed. The carrier lifetime was estimated to be 1.8 ns from the pulsed modulation of the LDs.