Miracle-dz/UniFAR-FTUs huggingface dataset:
Magnetodielectric effects at quantum critical fields in cobalt-containing garnets

Here we present a comparative study of the magnetic and crystal chemical properties of two Co2+ containing garnets, NaCa2Co2V3O12 and CaY2Co2Ge3O12. Both phases exhibit the onset of antiferromagnetic order at 8K and 6K respectively, as well as field-induced transitions in their magnetization at 1T and around 11 T. We find these field-dependent transitions correspond to quantum critical points that result in the suppression of antiferromagnetic order and that these transitions can be clearly seen using magnetocapacitance measurements. Finally, we perform detailed crystal chemistry analyses and complimentary density functional theory calculations to show that changes in the local environment of the Co-ions are responsible for differences in the two magnetic structures and their respective properties.
Mass transfer on a nuclear timescale in models of supergiant and ultra-luminous X-ray binaries

Context. The origin and number of the Galactic supergiant X-ray binaries is currently not well understood. They consist of an evolved massive star and a neutron star or black-hole companion. X-rays are thought to be generated from the accretion of wind material donated by the supergiant, while mass transfer due to Roche-lobe overflow is mostly disregarded because the high mass ratios of these systems are thought to render this process unstable. Aims. We investigate how the proximity of supergiant donor stars to the Eddington limit, and their advanced evolutionary stage, may influence the evolution of massive and ultra-luminous X-ray binaries with supergiant donor stars (SGXBs and ULXs). Methods. We constructed models of massive stars with different internal hydrogen and helium gradients (H/He gradients) and different hydrogen-rich envelope masses, and exposed them to slow mass-loss to probe the response of the stellar radius. In addition, we computed the corresponding Roche-lobe overflow mass-transfer evolution with our detailed binary stellar evolution code, approximating the compact objects as point masses. Results. We find that a H/He gradient in the layers beneath the surface, as it is likely present in the well-studied donor stars of observed SGBXs, can enable mass transfer in SGXBs on a nuclear timescale with a black-hole or a neutron star accretor, even for mass ratios in excess of 20. In our binary evolution models, the donor stars rapidly decrease their thermal equilibrium radius and can therefore cope with the inevitably strong orbital contraction imposed by the high mass ratio. We find that the orbital period derivatives of our models agree well with empirical values. We argue that the SGXB phase may be preceded by a common-envelope evolution. The envelope inflation near the Eddington limit means that this mechanism more likely occurs at high metallicity. Conclusion. Our results open a new perspective for understanding that SGBXs are numerous in our Galaxy and are almost completely absent in the Small Magellanic Cloud. Our results may also offer a way to find more ULX systems, to detect mass transfer on nuclear timescales in ULX systems even with neutron star accretors, and shed new light on the origin of the strong B-field in these neutron stars.
$C^{1,\alpha}$-regularity for surfaces with $H$ in $L^p$

In this paper we prove several results on the geometry of surfaces immersed in $\mathbf R^3$ with small or bounded $L^2$ norm of $|A|$. For instance, we prove that if the $L^2$ norm of $|A|$ and the $L^p$ norm of $H$, $p>2$, are sufficiently small, then such a surface is graphical away from its boundary. We also prove that given an embedded disk with bounded $L^2$ norm of $|A|$, not necessarily small, then such a disk is graphical away from its boundary, provided that the $L^p$ norm of $H$ is sufficiently small, $p>2$. These results are related to previous work of Schoen-Simon and Colding-Minicozzi.
Experimental and theoretical lifetimes and transition probabilities for spectral lines in Nb II

Aims. We have measured and calculated lifetimes of high lying levels in Nb II, and derived absolute transition probabilities by combining the lifetimes with experimental branching fractions.Methods. The lifetimes were measured using time-resolved laser-induced fluorescence in a two-photon and two-step excitation scheme. The branching fractions were measured in intensity calibrated spectra from a hollow cathode discharge, recorded with a Fourier transform spectrometer. The calculations were performed with the relativistic Hartree–Fock method including core polarization.Results. We report experimental lifetimes of 13 levels in the 4d3(4F)5d and 4d3(4F)6s subconfigurations, at an energy around 70 000 cm−1. By combining the lifetimes with experimental branching fractions absolute transition probabilities of 59 lines are derived. The experimental results are compared with calculated values.
Hydrogen diffusion and hydride formation in grain boundary rich magnesium

In den letzten Jahrzehnten wurde viel Forschung an Magnesium (Mg) betrieben. Das Ziel war der Einsatz als Wasserstoffspeicher in einer zukunftigen Energiewirtschaft. Magnesium ist dafur aufgrund seiner hohen Wasserstoffkapazitat pro Masse von 7,6 Gew% und pro Volumen von 110 kg/m³ ein vielversprechender Kandidat. Seine wirtschaftliche Anwendung ist allerdings beschrankt durch eine langsame Sorptionskinetik und eine zu hohe Desorptionstemperatur. Die kinetische Einschrankung stammt von einer blockierenden Magnesiumdihydridschicht (MgH2), welche sich um das Magnesium bildet. Da Wasserstoff (H) nur sehr langsam durch MgH2 diffundiert, behindert die blockierende Schicht die gesamte Kinetik der Hydridbildung. Diese Einschrankung kann aber moglicherweise durch Korngrenzen (KG) umgangen werden. In dieser Arbeit wurde versucht den Einfluss der Diffusion in KG von der insgesamten Diffusion in MgH2 zu trennen. Um dieses Ziel zu erreichen wurden dabei experimentelle Methoden wie die Gasvolumetrie, in situ Widerstandsmessung und in situ XRD mit der numerischen Methode der Finite-Elemente (FEM) Simulation kombiniert. Die experimentellen Methoden erlaubten den globalen Diffusionskoeffizienten in dunnen Mg Schichten bei Anderung von verschiedenen Parametern wie Kornstruktur, zugesetzten Elementen oder dem Druck zu messen. Dieser insgesamte Diffusionskoeffizient beinhaltet dabei den Einfluss des Korngrenzendiffusionskoeffizienten und des Korndiffusionskoeffizienten. Die FEM Simulationen erlaubten diese beide Komponenten zu trennen und einzeln zu andern. Zusammen genommen zeigten die experimentellen und numerischen Methoden, dass die KG den gesamten Diffusionsprozess dominieren. Die Wasserstoffdiffusion in den Kornern ist zu langsam fur eine praktische Anwendung. Zusatzlich wurde die Kornstruktur in den dunnen Schichten in ex situ und in situ TEM Untersuchungen bestimmt. Es zeigte sich das die Hydridbildung zu einer starken Reduktion der Korngrose in den Proben fuhrt. Diese Ergebnisse sind wichtig fur das Design von zukunftigen Wasserstoffspeichern aus Mg: Erstens braucht ein guter Speicher eine hohe Korngrenzendichte (dies entspricht kleinen Korngrosen). Nur so kann H den Grosteil des Mg erreichen und Hydrid formen. Dies ist in dunnen Schichten durch die automatische Reduktion der Korngrose gegeben. Zweitens sollte die Diffusion durch die Korngrenzen weiter erhoht werden. Die Ergebnisse dieser Arbeit zeigen, dass die z.B. moglich ist indem kleine Konzentrationen von Eisen beigemischt werden.
Lagrangian investigations of velocity gradients in compressible turbulence: lifetime of flow-field topologies

We perform Lagrangian investigations of the dynamics of velocity gradients in compressible decaying turbulence. Specifically, we examine the evolution of the invariants of the velocity-gradient tensor. We employ well-resolved direct numerical simulations over a range of Mach number along with a Lagrangian particle tracker to examine trajectories of fluid particles in the space of the invariants of the velocity gradient tensor. This allows us to accurately measure the lifetimes of major topologies of compressible turbulence and provide an explanation of why some selective topologies tend to exist longer than the others. Further, the influence of dilatation on the lifetime of various topologies is examined. Finally, we explain why the so-called conditional mean trajectories (CMT) used previously by several researchers fail to predict the lifetime of topologies accurately.
Conjugate heat transfer enhancement of laminar slot jets with various nanofluids on an array of protruding hot sources using MPM approach

Abstract Conjugate heat transfer in laminar slot jets impinging on multiple protruding hot sources using various nanofluids has been investigated numerically by employing (i) a mass-based modeling and an (ii) Eulerian-based multi-phase modeling (MPM). Various parameters such as streamline contours, isotherm profiles, local Nusselt number (Nu), average Nusselt number (Nuavg) are evaluated for different nanofluids (Ag–water, Al2O3–water, CuO–water and TiO2–water), various range of Reynolds number (Re), particle volume fraction (ϕ), diameter of the nanoparticle (d) and thermal conductivity ratio (kr). The steady, laminar, incompressible and two-dimensional flows are considered for the analysis. Finite-volume method with SIMPLE algorithm is used to solve continuity, momentum and energy equations along with boundary conditions. The highest heat transfer rate is achieved at ϕ = 0.05 for any protruding blocks and Reynolds number. Conjugate heat transfer rate of nanofluids increases with decreasing the diameter of nanoparticles. Here, Al2O3–water nanofluid is found to exhibit highest average Nusselt number compared to other nanofluids. The mixture based MPM approach with considering slip velocity yields higher heat transfer rate compared to the results obtained by single phase modeling approach.
Three Dimensional Quasi-Para-Sasakian Manifolds Satisfying Certain Curvature Conditions

The object of the present paper is to study some classes of 3-dimensional quasi-para-Sasakian manifolds with beta =const. We investigated 3-dimensional quasi-para-Sasakian manifolds with beta=const. satisfying the curvature conditions P:Q = 0; Q:P = 0; P:R = 0, where P is the projective curvature tensor, Q is the Ricci operator and R is the Riemannian curvature tensor. Also, a 3-dimensional concircularly flat quasi-para-Sasakian manifold with beta =const. is studied. Finally, an example of 3-dimensional proper quasi-para-Sasakian manifold with beta =const. is given.
Event‐based network consensus with antagonistic interactions and communication delay

In this study, the consensus problem is investigated for the multi-agent systems with antagonistic interactions and communication delay under the event-triggered control protocol. For the directed signed networks, an event-based interaction protocol is first proposed. Then it is shown that with the proposed protocol, bipartite consensus can be realised for the structurally balanced signed networks with distributed communication delay. As for the structurally unbalanced signed networks with communication delay, it is proved that consensus can also be reached under the proposed event-triggered scheme and the final consensus value is zero. It should be emphasised that the proposed event-triggered controllers depend only on the local information. Furthermore, Zero phenomenon can be excluded, and the positive lower bound of the inter-event times is simultaneously provided. Finally, the effectiveness of proposed event-triggered schemes is demonstrated by one numerical example.
On the Castelnuovo-Severi inequality for a double covering

Let C be a smooth projective irreducible complex algebraic curve of genus g ::;:: 2. We denote g~ by a 1-dimensional possibly incomplete linear system of degree d on C. For any d ::;:: g + 1, every curve C of genus g has a base point free g~ which may be taken as a general pencil of a general element in wf~9 (C) = J(C). If Cis a hyperelliptic curve with the hyperelliptic pencil g~, it is well-known that any base point free pencil of degree d :S: g is a subsystem of the complete rg~ where r = ~; cf. [1, p.109]. In particular, the only base point free and complete pencil on a hyperelliptic curve is the g~. On the other hand, a non-hyperelliptic curve C has a base point free and complete pencil of degree g, by taking off g 2 general points from the very ample canonical linear system IKciFurthermore, a theorem of Harris asserts that any non-hyperelliptic curve of genus g has a base point free and complete pencil of degree g -1; cf. [1, p.372]. However, this seemingly simple fact requires a proof which is somewhat involved. Especially, in case C is a hi-elliptic curve, one needs to show that the variety WJ~ 1 (C) consisting of special pencils of degree g 1 is reducible by using enumerative methods; see also [3, Proposition 3.3],[6, Proposition 2.5] for the other proofs concerning the existence of a base point free and complete pencil 9~~ 1 on a hi-elliptic curve. At this point, it is worthwhile to recall the following classical result known as Castelnuovo-Severi inequality.
Graphical Methods for Image Compositing and Completion

This thesis is concerned with problems encountered in image-based rendering (IBR) systems. The significance of such systems is increasing as virtual reality as well as augmented reality are finding their way into many applications, from entertainment to military. Particularly, I propose methods that are based on graph theory to address the open problems in the literature of image and video compositing, and scene completion. For a visually plausible compositing, it is first required to separate the object to be composed from the background it was initially captured against, a problem that is known as natural image matting. It aims, using some user interactions, to calculate a map that depicts how much a background color(s) contributes to the color of every other pixel in an image. My contributions to matting increase the accuracy of the map calculation as well as automate the whole process, by eliminating the need for user interactions. I propose several techniques for sampling user interactions which enhance the quality of the calculated maps. They rely on statistics of non-parametric color models as well as graph transduction and iterative graph cut techniques. The presented sampling strategies lead to state-of-the-art separation, and their efficiency was acknowledged by the standard benchmark in the literature. I have adopted the Gestalt laws of visual grouping to formulate a novel cost function to automate the generation of interactions that otherwise have to be provided manually. This frees the matting process from a critical limitation when used in rendering contexts. Scene completion is another task that is often required in IBR systems. This document presents a novel image completion method that overcomes a few drawbacks in the literature. It adopts a binary optimization technique to construct an image summary, which is then shifted according to a map, calculated with combinatorial optimization, to complete the image. I also present the formulation with which the proposed method can be extended to complete scenes, rather than images, in a stereoscopically and temporallyconsistent manner.
Global kernel estimator and test of varying‐coefficient autoregressive model

We propose a varying‐coefficient autoregressive model that contains additive models, varying‐ coefficient models, partially linear models and low‐dimensional interaction models as special cases. A global kernel backfitting method is proposed for the estimation and inference of parameters and unknown functions in this model. Key large‐sample results are established, including estimation consistency, asymptotic normality and the generalized likelihood ratio test for parameters and non‐parametric functions. The proposed methodology is examined by simulation studies and applied to examine the relationship between suicide news reports in the three leading newspapers and the daily number of suicides in Taiwan. The relationship between the media reporting and suicide incidence has been established and explored. The Canadian Journal of Statistics 47: 487–519; 2019 © 2019 Statistical Society of Canada
PENERAPAN STRATEGI KOGNITIF MULTIPURPOSE DAN MOTIVASI BERPRESTASI PADA MATA KULIAH PENDIDIKAN KEWARGANEGARAAN, STUDI PADA MAHASISWA FKIP UNP KEDIRI.

Masalah yang diteliti dirumuskan sebagai berikut: 1. Apakah penerapan strategi kognitif multipurpose, metode rehearsal, imageri dan mnemonics memberikan pengaruh yang berbeda terhadap hasil belajar mahasiswa? 2. Apakah motivasi berprestasi tinggi dengan rendah berpengaruh terhadap perolehan hasil belajar mahasiswa? 3. Adakah pengaruh interaktif penerapan strategi kognitif dan motivasi berprestasi terhadap hasil belajar mahasiswa? Penelitian ini menggunakan rancangan eksperimen model post design only. Variable bebas yang diteliti adalah penerapan strategi kognitif multipurpose yang terdiri atas 3 metode yaitu reheasal, mnemonic dan imagery. Variable terikatnya adalah hasil belajar mahasiswa dan variable moderatornya adalah motivasi berprestasi. Populasi penelitian ini adalah mahasiswa semester III (tiga) yang menempuh matakuliah PKN pada semester ganjil tahun akademik 2015/2016, yaitu mahasiswa jurusan pendidikan Ekonomi-Akuntansi (PEA) sebanyak: 32 mahasisiwa, jurusan PKN sebanyak 23 mahasiswa, dan jurusan pendidikan Matematika sebanyak 40 mahasiswa. Populasi tersebut seluruhnya digunakan sebagai sampel penelitian.Instrument yang digunakan untuk pengumpulan data adalah questioner motivasi berprestasi dan tes hasil belajar, sedangakan analisis datanya menggunakan anava 2-jalur. Simpulan hasil penelitian ini adalah: 1. Terdapat perbedaan yang signifikan pada hasil belajar mahasiswa antara yang menerapkan strategi kognitif multipurpose; reheasal, imagery dan mnemonics. 2. Terdapat perbedaan yang signifikan pada hasil belajar mahasiswa antara yang memiliki motivasi berprestasi tinggi dengan rendah. 3. Terdapat interaksi yang signifikan antara penerapan strategi kognitif dan motivasi berprestasi terhadap hasil belajar mahasiswa.
Distance‐based analysis of variance for brain connectivity

The field of neuroimaging dedicated to mapping connections in the brain is increasingly being recognized as key for understanding neurodevelopment and pathology. Networks of these connections are quantitatively represented using complex structures, including matrices, functions, and graphs, which require specialized statistical techniques for estimation and inference about developmental and disorder‐related changes. Unfortunately, classical statistical testing procedures are not well suited to high‐dimensional testing problems. In the context of global or regional tests for differences in neuroimaging data, traditional analysis of variance (ANOVA) is not directly applicable without first summarizing the data into univariate or low‐dimensional features, a process that might mask the salient features of high‐dimensional distributions. In this work, we consider a general framework for two‐sample testing of complex structures by studying generalized within‐group and between‐group variances based on distances between complex and potentially high‐dimensional observations. We derive an asymptotic approximation to the null distribution of the ANOVA test statistic, and conduct simulation studies with scalar and graph outcomes to study finite sample properties of the test. Finally, we apply our test to our motivating study of structural connectivity in autism spectrum disorder.
THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S4G): PRECISE STELLAR MASS DISTRIBUTIONS FROM AUTOMATED DUST CORRECTION AT 3.6 μm

The mid-infrared is an optimal window to trace stellar mass in nearby galaxies and the 3.6 &mgr; m ? > IRAC band has been exploited to this effect, but such mass estimates can be biased by dust emission. We present our pipeline to reveal the old stellar flux at 3.6 μm and obtain stellar mass maps for more than 1600 galaxies available from the Spitzer Survey of Stellar Structure in Galaxies (S4G). This survey consists of images in two infrared bands (3.6 and 4.5 &mgr; m ? > ), and we use the Independent Component Analysis (ICA) method presented in Meidt et al. to separate the dominant light from old stars and the dust emission that can significantly contribute to the observed 3.6 &mgr; m ? > flux. We exclude from our ICA analysis galaxies with low signal-to-noise ratio ( S / N < 10 ? > ) and those with original [3.6]–[4.5] colors compatible with an old stellar population, indicative of little dust emission (mostly early Hubble types, which can directly provide good mass maps). For the remaining 1251 galaxies to which ICA was successfully applied, we find that as much as 10%–30% of the total light at 3.6 &mgr; m ? > typically originates from dust, and locally it can reach even higher values. This contamination fraction shows a correlation with specific star formation rates, confirming that the dust emission that we detect is related to star formation. Additionally, we have used our large sample of mass estimates to calibrate a relationship of effective mass-to-light ratio (M/L) as a function of observed [3.6]–[4.5] color: log ( M / L ) = ? > − 0.339 ( ± 0.057 ) × ? > ( [ 3.6 ] − [ 4.5 ] ) − 0.336 ( ± 0.002 ) ? > . Our final pipeline products have been made public through IRSA, providing the astronomical community with an unprecedentedly large set of stellar mass maps ready to use for scientific applications.
Characterising pointsets in PG(4,q) that correspond to conics

We consider a non-degenerate conic in $\PG(2,q^2)$, $q$ odd, that is tangent to $\ell_\infty$ and look at its structure in the Bruck-Bose representation in $\PG(4,q)$. We determine which combinatorial properties of this set of points in $\PG(4,q)$ are needed to reconstruct the conic in $\PG(2,q^2)$. That is, we define a set $\C$ in $\PG(4,q)$ with $q^2$ points that satisfies certain combinatorial properties. We then show that if $q\ge 7$, we can use $\C$ to construct a regular spread $\S$ in the hyperplane at infinity of $\PG(4,q)$, and that $\C$ corresponds to a conic in the Desarguesian plane $\P(\S)\cong\PG(2,q^2)$ constructed via the Bruck-Bose correspondence.
Superradiance in a Large Cloud of Cold Atoms in the Linear-Optics Regime

Superradiance has been extensively studied in the 1970s and 1980s in the regime of superfluores-cence, where a large number of atoms are initially excited. Cooperative scattering in the linear-optics regime, or " single-photon superradiance ", has been investigated much more recently, and superra-diant decay has also been predicted, even for a spherical sample of large extent and low density. Here, we demonstrate this effect experimentally by directly measuring the decay rate of the off-axis fluorescence of a large and dilute cloud of cold atoms after the sudden switch-off of a low-intensity laser driving the atomic transition. We show that, at large detuning, the decay rate increases with the on-resonance optical depth. In contrast to forward scattering, the superradiant decay of off-axis fluorescence is suppressed near resonance due to attenuation and multiple-scattering effects.
Adaptive output feedback control for a class of non-affine nonlinear systems

The adaptive tracking control problem of a class of uncertain SISO non-affine nonlinear systems is considered under the condition that system states are immeasurable and non-affine nonlinear function is possibly discontinuous. In order to remove the restriction that non-affine nonlinear function must be continuous, a novel model is developed for the non-affine nonlinear function. Combined with this model, an adaptive output feedback controller is proposed by utilising a high gain observer to estimate the immeasurable system states. It is proved that all the signals in the closed-loop system are bounded and the tracking error can be made arbitrarily small by choosing appropriately design parameters. Finally, simulation example is provided to demonstrate the effectiveness of the proposed approach.