Miracle-dz/UniFAR-FTUs huggingface dataset:
A model for cyclotron resonance scattering features

Aims. We study the physics of cyclotron line formation in the high-energy spectra of accreting X-ray pulsars. In particular, we link numerical predictions for the line profiles to results from observational data analysis. Therefore, first we investigate the theoretical predictions and the significance of our model parameters, and second we aim at the development of a model to fit cyclotron lines in observational data. Methods. Simulations were performed using Monte Carlo methods. The data were extracted with HEADAS 6.1. 1 and INTEGRAL OSA 5.1. A convolution model for the cyclotron line shapes was implemented for the XSPEC spectral analysis software package and for data packages compatible with XSPEC local models. Results. We predict the shapes of cyclotron lines for different prescribed physical settings. The calculations assume that the line-forming region is a low-density electron plasma, which is of cylindrical or slab geometry and which is exposed to a uniform, sub-critical magnetic field. We investigate the dependence of the shape of the fundamental line on angle, geometry, optical depth and temperature. We also discuss variations of the line ratios for non-uniform magnetic fields. We have developed a new convolution and interpolation model to simulate line features regardless of any a priori assumed shape of the neutron star continuum. Fitting RXTE and INTEGRAL data of the accreting X-ray pulsar V0332+53 with this model gives a qualitative description of the data. Strong emission wings of the fundamental cyclotron feature as predicted by internally irradiated plasma geometries are in principle observable by todays instruments but are not formed in V0332+53, hinting at a bottom illuminated slab geometry for line formation.
Asymptotics for multilinear averages of multiplicative functions

Abstract A celebrated result of Halász describes the asymptotic behavior of the arithmetic mean of an arbitrary multiplicative function with values on the unit disc. We extend this result to multilinear averages of multiplicative functions providing similar asymptotics, thus verifying a two dimensional variant of a conjecture of Elliott. As a consequence, we get several convergence results for such multilinear expressions, one of which generalises a well known convergence result of Wirsing. The key ingredients are a recent structural result for multiplicative functions with values on the unit disc proved by the authors and the mean value theorem of Halász.
Degree Growth, Linear Independence and Periods of a Class of Rational Dynamical Systems

We introduce and study algebraic dynamical systems generated by triangular systems of rational functions. We obtain several results about the degree growth and linear independence of iterates as well as about possible lengths of trajectories generated by such dynamical systems over finite fields. Some of these results are generalisations of those known in the polynomial case, some are new even in this case.
Discrete vector on-site vortices

We study discrete vortices in coupled discrete nonlinear Schrödinger equations. We focus on the vortex cross configuration that has been experimentally observed in photorefractive crystals. Stability of the single-component vortex cross in the anti-continuum limit of small coupling between lattice nodes is proved. In the vector case, we consider two coupled configurations of vortex crosses, namely the charge-one vortex in one component coupled in the other component to either the charge-one vortex (forming a double-charge vortex) or the charge-negative-one vortex (forming a, so-called, hidden-charge vortex). We show that both vortex configurations are stable in the anti-continuum limit, if the parameter for the inter-component coupling is small and both of them are unstable when the coupling parameter is large. In the marginal case of the discrete two-dimensional Manakov system, the double-charge vortex is stable while the hidden-charge vortex is linearly unstable. Analytical predictions are corroborated with numerical observations that show good agreement near the anti-continuum limit, but gradually deviate for larger couplings between the lattice nodes.
A Monte Carlo Study of Recovery of Weak Factor Loadings in Confirmatory Factor Analysis

The recovery of weak factors has been extensively studied in the context of exploratory factor analysis. This article presents the results of a Monte Carlo simulation study of recovery of weak factor loadings in confirmatory factor analysis under conditions of estimation method (maximum likelihood vs. unweighted least squares), sample size, loading size, factor correlation, and model specification (correct vs. incorrect). The effects of these variables on goodness of fit and convergence are also examined. Results show that recovery of weak factor loadings, goodness of fit, and convergence are improved when factors are correlated and models are correctly specified. Additionally, unweighted least squares produces more convergent solutions and successfully recovers the weak factor loadings in some instances where maximum likelihood fails. The implications of these findings are discussed and compared to previous research.
Convergence of graphs with intermediate density

We propose a notion of graph convergence that interpolates between the Benjamini--Schramm convergence of bounded degree graphs and the dense graph convergence developed by Laszlo Lovasz and his coauthors. We prove that spectra of graphs, and also some important graph parameters such as numbers of colorings or matchings, behave well in convergent graph sequences. Special attention is given to graph sequences of large essential girth, for which asymptotics of coloring numbers are explicitly calculated. We also treat numbers of matchings in approximately regular graphs. We introduce tentative limit objects that we call graphonings because they are common generalizations of graphons and graphings. Special forms of these, called Hausdorff and Euclidean graphonings, involve geometric measure theory. We construct Euclidean graphonings that provide limits of hypercubes and of finite projective planes, and, more generally, of a wide class of regular sequences of large essential girth. For any convergent sequence of large essential girth, we construct weaker limit objects: an involution invariant probability measure on the sub-Markov space of consistent measure sequences (this is unique), or an acyclic reversible sub-Markov kernel on a probability space (non-unique). We also pose some open problems.
Orbital symmetry reconstruction and strong mass renormalization in the two-dimensional electron gas at the surface of KTaO3

We study, using angle-resolved photoemission spectroscopy, the two-dimensional electron gas (2DEG) at the surface of KTaO3 (KTO), a wide-gap insulator with strong spin-orbit coupling (SOC). We find that this 2DEG is a genuinely different physical state with respect to the bulk: the orbital symmetries of its subbands are entirely reconstructed and their masses are renormalized. This occurs because the values of the SOC, the Fermi energy, and the subband splittings become comparable in the 2DEG. Additionally, we identify an F-center-like heavy band resulting from the polar nature of the KTO surface.
Three-dimensional imaging by a microscope

In transmission microscopy, many objects are three dimensional, that is, they are thicker than the depth of focus of the imaging system. The three-dimensional (3-D) image-intensity distribution consists of a series of two-dimensional images (optical slices) with different parts of the object in focus. First, we deal with the fundamental limitations of 3-D imaging with classical optical systems. Second, a transfer theory of 3-D image formation is derived that relates the 3-D object (complex index of refraction) to the 3-D image intensity distribution in first-order Born approximation. This theory applies to weak objects that do not scatter much light. Since, in a microscope, the illumination is neither coherent nor completely incoherent, a theory for partially coherent light is needed, but in this case the object phase distribution and the absorptive parts of the object play different roles. Finally, some experimental results are presented.
Orbital stability of numerical periodi nonlinear Schrödinger equation

This work is devoted to the study of the system that arises by discretization of the periodic nonlinear Schrodinger equation in dimension one. We study the existence of the discrete ground states for this system and their stability property when the potential parameter ¾ is small enough: i.e., if the initial data are close to the ground state, the solution of the system will remain near to the orbit of the discrete ground state forever. This stability property is an appropriate tool for proving the convergence of the numerical method.
Advanced metrology: an essential support for the surface finishing of high performance x-ray optics

The performance of x-ray beamlines at 3rd generation synchrotron radiation sources and Free Electron Lasers (FELs) is limited by the quality of the state of the art optical elements. Proposed FEL beamlines require optical components which are of better quality than is available from the optical manufacturing technology of today. As a result of a joint research project (Nanometer Optik Komponenten - NOK) coordinated by BESSY, involving both metrologists and manufacturers it is possible now to manufacture optical components beyond the former limit of 0.1 arcsec rms slope error [1, 2]. To achieve the surface finishing of optical components with a slope error in the range of 0.04 arcsec rms (for flat or spherical surfaces up to 300 mm in length) by polishing and finally by ion beam figuring technology it is essential that the optical surface be mapped and the mapping data used as input for the multiple ion beam figuring stages. Metrology tools of at least five times superior accuracy to that required of the component have been developed in the course of the project. The Nanometer Optical Component measuring Machine (NOM) was developed at BESSY for line and area measurements of the figure of optical components used at grazing incidence in synchrotron radiation beamlines. Surfaces up to 730 cm2 have been measured with the NOM a measuring uncertainty in the range of 0.01 arcsec rms and a correspondingly high reproducibility [3]. Three dimensional measurements were used to correct polishing errors some nanometers high and only millimeters in lateral size by ion beam treatment. The design of the NOM, measurement results and results of NOM supported surface finishing by ion beam figuring will be discussed in detail. The improvement of beamline performance by the use of such high quality optical elements is demonstrated.
Observation of inhomogeneous domain nucleation in epitaxial Pb(Zr,Ti)O3 capacitors

We investigated domain nucleation process in epitaxial Pb(Zr,Ti)O3 capacitors under a modified piezoresponse force microscope. We obtained domain evolution images during polarization switching process and observed that domain nucleation occurs at particular sites. This inhomogeneous nucleation process should play an important role in an early stage of switching and under a high electric field. We found that the number of nuclei is linearly proportional to log(switching time), suggesting a broad distribution of activation energies for nucleation. The nucleation sites for a positive bias differ from those for a negative bias, indicating that most nucleation sites are located at the ferroelectric/electrode interfaces.
Empirical normal-mode analysis of atmospheric data

Abstract The theory of empirical orthogonal functions (EOFs) is generalized in the context of normal modes on unidirectional sheared flows, at first using small disturbance to a monotonic potential vorticity basic state. A wave function is introduced (so called because of a partial analogy with quantum mechanical wave function), via the pseudomomentum, and is used to define the covariance matrix needed in an EOF analysis. The resulting new formalism comprises a fundamental, simpler and more physically insightful, version of EOF theory: it allows empirical reconstruction of the normal modes excited in an atmospheric time series, their respective variances, and phase speed relationship. This new approach permits quantitative and qualitative discussions of the underlying wave mechanisms present in a sheared flow. The theory is given for a hierarchy of models starting with the linearized quasigeostrophic equations. The extent to which these concepts carry over to nonlinear finite-amplitude disturbance is inve.
Propagation of the Gabor Wave Front Set for Schr\"odinger Equations with non-smooth potentials

We consider Scr\"odinger equations with real-valued smooth Hamiltonians, and non-smooth bounded pseudo-differential potentials, whose symbols may be not even differentiable. The well-posedness of the Cauchy problem is proved in the frame of the modulation spaces, and results of micro-local propagation of singularities are given in terms of Gabor wave front sets.
On the reduction of PDE's problems in the half-space, under the slip boundary condition, to the corresponding problems in the whole space

The resolution of a very large class of linear and non-linear, stationary and evolutive partial differential problems in the half-space (or similar) under the slip boundary condition is reduced here to that of the corresponding results for the same problem in the whole space. The approach is particularly suitable for proving new results in strong norms. To determine whether this extension is available, turns out to be a simple exercise. The verification depends on a few general features of the functional space X related to the space variables. Hence, we present an approach as much as possible independent of the particular space X. We appeal to a reflection technique. Hence a crucial assumption is to be in the presence of flat boundaries (see below). Instead of stating "general theorems" we rather prefer to illustrate how to apply our results by considering a couple of interesting problems. As a main example, we show that the resolution of a class of problems for the evolution Navier-Stokes equations under a slip boundary condition can be reduced to that of the corresponding results for the Cauchy problem. In particular, we show that sharp vanishing viscosity limit results that hold for the evolution Navier-Stokes equations in the whole space can be extended to the boundary value problem in the half-space. We also show some applications to non-Newtonian fluid problems.
Quaternions, polarizations and class numbers

We study abelian varieties $A$ with multiplication by a totally indefinite quaternion algebra over a totally real number field and give a criterion for the existence of principal polarizations on them in pure arithmetic terms. Moreover, we give an expression for the number $\pi_0(A)$ of isomorphism classes of principal polarizations on $A$ in terms of relative class numbers of CM fields by means of Eichler's theory of optimal embeddings. As a consequence, we exhibit simple abelian varieties of any even dimension admitting arbitrarily many non-isomorphic principal polarizations. On the other hand, we prove that $\pi_0(A)$ is uniformly bounded for simple abelian varieties of odd square-free dimension.
Ion emission from plasma-focus facilities

Angular- and energy-distributions of ions emitted from different plasma-focus (PF) devices of energy capacity ranging from 3.6 kJ to about 200 kJ are presented. Also compared are space- and time- resolved ion signals obtained from different PF facilities. Comparative studies show some similarity features in the ion emission characteristics.
Annealing effects on CoFeB-MgO magnetic tunnel junctions with perpendicular anisotropy

We studied annealing effects on perpendicular anisotropy in CoFeB-MgO magnetic tunnel junctions. The results show that annealing is an effective method to improve the perpendicular anisotropy of a CoFeB-MgO system. It is found that a thicker CoFeB layer requires a higher annealing temperature to buildup its perpendicular anisotropy. However, perpendicular anisotropy could be seriously degraded if the annealing temperature is more than 350 °C. Our study suggests that CoFeB thickness should be optimized so that the required annealing temperature window for perpendicular anisotropy could match the annealing temperature for high magnetoresistance. In this work, the perpendicular anisotropy energy density of 2.5 × 106 erg/cm3 was achieved with tunnel magnetoresistive value exceeding 70%. The use of CoFeB films will enable the development of high density nonvolatile memory with size down to 30 nm.
Codimension-one attracting sets in $\mathbb{P}^{k}(\mathbb{C})$

We are interested in attracting sets of $\mathbb{P}^{k}(\mathbb{C})$ which are of small topological degree and of codimension one. We first show that there exists a large family of examples. Then we study their ergodic and pluripotential theoretic properties.
Psychological Capital as a Predictor of Organizational Commitment of Executive Board Administrators of Faculty at State University of Malang

Previous research on psychological capital and organizational commitment in education or student organizations is still very limited, and no research has been conducted during the transition period from pandemic to endemic. This study aims to determine the contribution of psychological capital to organizational commitment simultaneously and partially. The subject of this study is the management of the Faculty Student Executive Board at UM for the period of 2022. The instruments used are Meyer and Allen’s scale of organizational commitment and Luthans’ scale of psychological capital. The analysis of the research data used is multiple linear regression analysis. The results showed that the F-test = 12.873 (p < .05), which means that psychological capital (self-efficacy, resilience, optimism, and hope) had a concurrent effect on organizational commitment and the results of the coefficient of determination (R-squared) showed a contribution of psychological capital (self-efficacy, resilience, optimism, and hope) of 29.9%. The results of t-test showed that self-efficacy dimension t=3.190 (p < .05) and hope dimension t=2.583 (p < .05), which means that self-efficacy and hope have partially significant influence on organizational commitment. The results of the t-optimistic test are t=. 660 (p > .05) and the resilience dimension t=. 161 (p > .05), which means that it has no significant influence on organizational commitment. The contribution of effective self-efficacy donations was 16.20% and the effective contribution of hope was 10.10%. Suggestions for organizations or administrators to improve self-efficacy are to provide positive feedback, social recognition, to give management experience of mastery. Individual characteristics have also been shown to have a significant influence on organizational commitment [3]. Other research shows that employees with high quality of work life have high organizational commitment, as well as psychological capital factors.
Bayesian hierarchical structured variable selection methods with application to molecular inversion probe studies in breast cancer

The analysis of genomics alterations that may occur in nature when segments of chromosomes are copied (known as copy number alterations) has been a focus of research to identify genetic markers of cancer. One high throughput technique that has recently been adopted is the use of molecular inversion probes to measure probe copy number changes. The resulting data consist of high dimensional copy number profiles that can be used to ascertain probe‐specific copy number alterations in correlative studies with patient outcomes to guide risk stratification and future treatment. We propose a novel Bayesian variable selection method, the hierarchical structured variable selection method, which accounts for the natural gene and probe‐within‐gene architecture to identify important genes and probes associated with clinically relevant outcomes. We propose the hierarchical structured variable selection model for grouped variable selection, where simultaneous selection of both groups and within‐group variables is of interest. The hierarchical structured variable selection model utilizes a discrete mixture prior distribution for group selection and group‐specific Bayesian lasso hierarchies for variable selection within groups. We provide methods for accounting for serial correlations within groups that incorporate Bayesian fused lasso methods for within‐group selection. Through simulations we establish that our method results in lower model errors than other methods when a natural grouping structure exists. We apply our method to a molecular inversion probe study of breast cancer and show that it identifies genes and probes that are significantly associated with clinically relevant subtypes of breast cancer.
Strong instability of standing waves for nonlinear Schr\"odinger equations with attractive inverse power potential

We study the strong instability of standing waves $e^{i\omega t}\phi_\omega(x)$ for nonlinear Schr\"{o}dinger equations with an $L^2$-supercritical nonlinearity and an attractive inverse power potential, where $\omega\in\mathbb{R}$ is a frequency, and $\phi_\omega\in H^1(\mathbb{R}^N)$ is a ground state of the corresponding stationary equation. Recently, for nonlinear Schr\"odinger equations with a harmonic potential, Ohta (2018) proved that if $\partial_\lambda^2S_\omega(\phi_\omega^\lambda)|_{\lambda=1}\le0$, then the standing wave is strongly unstable, where $S_\omega$ is the action, and $\phi_\omega^\lambda(x)\mathrel{\mathop:}=\lambda^{N/2}\phi_\omega(\lambda x)$ is the scaling, which does not change the $L^2$-norm. In this paper, we prove the strong instability under the same assumption as the above-mentioned in inverse power potential case. Our proof is applicable to nonlinear Schr\"odinger equations with other potentials such as an attractive Dirac delta potential.
Emission from an inhomogeneous layer with irregular interfaces

A theoretical model for microwave emission from an inhomogeneous layer has been developed using the radiative transfer method. The top and bottom boundaries of the layer are assumed to be randomly rough surfaces, and the scatter characteristics are assumed to be describable by the Kirchhoff scatter model. The presence of an irregular top boundary is found to cause a slower angular trend than the case of a plane layer and causes, in addition, a rise in temperature if the layer permittivity is large. On the other hand, if only the bottom boundary of the layer is rough, a rise in emission is observed relative to the plane layer. When both the top and the bottom boundaries are rough, the emissions at small nadir angles are closer to those of a layer with a rough bottom boundary, and the emissions at large nadir angles are closer to those of a layer with a rough top boundary. A comparison of the layer model with reported angular measurements from a snow layer at three different frequencies and polarizations shows promise for such a model. An additional comparison of emission versus the depth of a snow pile indicates that an irregular snow ground interface causes higher emissions at small depths. This fact is necessary to explain the observed measurements.