Miracle-dz/UniFAR-FTUs huggingface dataset:
Bismuth-doped optical fibres: A new breakthrough in near-IR lasing media

Recent results demonstrate that bismuth-doped optical fibres have considerable potential as near-IR active lasing media. This paper examines bismuth-doped fibres intended for the fabrication of fibre lasers and optical amplifiers and reviews recent results on the luminescence properties of various types of bismuth-doped fibres and the performance of bismuth-doped fibre lasers and optical amplifiers for the spectral range 1150 — 1550 nm. Problems are discussed that have yet to be solved in order to improve the efficiency of the bismuth lasers and optical amplifiers.
Locally homogeneous connections on principal bundles over hyperbolic Riemann surfaces

Let $(M,g)$ be a connected, compact, oriented, locally homogeneous Riemannian manifold, $K$ be a connected, compact Lie group, and $p:P\to M$ be a principal $K$-bundle on $M$. A connection on $P$ will be called locally homogeneous (LH) if for every two points $x$, $x'\in M$ there exist open neighborhoods $U\ni x$, $U'\ni x'$ , an isometry $\varphi:U\to U'$ such that $\varphi(x)=x'$, and a $\varphi$-covering bundle isomorphism $\Phi:P_U\to P_{U'}$ which preserves the connection. If this condition holds, then $P$ can be naturally endowed with a LH metric, so the classification of LH connections on bundles over a given manifold $M$ is related to the classification of geometric manifolds which are fibre bundles over $M$. This yields a strong motivation for studying the following general classification problem: given a compact LH Riemannian manifold $(M,g)$, and a compact Lie group $K$, classify up to isomorphism, all pairs $(P,A)$ consisting of a principal $K$-bundle $P$ on $M$ and a LH connection $A$ on $P$. Using a general theorem stating that any LH pair $(P,A)$ on $M$ is obtained as a quotient of a (globally) homogeneous pair on the universal covering $\tilde M$, this problem reduces to the classification of homogeneous pairs on $\tilde M$. This leads naturally to moduli spaces which can be described explicitly. In this article, we will illustrate our general classification method, and describe explicitly the moduli spaces of LH connections with structure group $K=\mathrm{S}^1$, $\mathrm{PU}(2)$ on hyperbolic Riemann surfaces.
Observations of boundary-layer structure over complex terrain

Turbulence data collected in an area of complex terrain using a number of instrument packages attached to the tether cable of a captive balloon are presented. Eddy correlation measurements of the turbulent momentum flux are used to determine the magnitude of the roughness length from the drag coefficient and also to show that the roughness length is a useful concept in parametrizing the surface stress in such areas. the relationship between the terrain characteristics and the roughness length is examined using a simple formula, results from a numerical model and previous experimental estimates of the roughness length for complex terrain. It is found that a formula based on numerical model results for separated flows gives reasonable predictions and that the measured roughness length is representative of an area of order 100 km2. Non-dimensionalized turbulence data are compared with similar data obtained over flat homogeneous surfaces. This comparison suggests that the structure of the turbulent boundary layer over complex terrain is remarkably similar to that over flat homogeneous surfaces. Because of the limitations of fixed point measurements in complex terrain, results from a numerical study of turbulent flow over two-dimensional sinusoidal orography are shown to indicate the magnitudes of the perturbations introduced into the boundary-layer flow by large undulations in the underlying surface. the model results demonstrate the validity of the analysis carried out with the data.
Excess vacancies in high energy ion implanted SiGe

Excess vacancies generated by high energy implantation with 1.2MeV Si+ and 2MeV Ge+ ions in SiGe were investigated after rapid thermal annealing at 900°C. Excess vacancies were probed by decoration with Cu and measuring the Cu profile by secondary ion mass spectrometry. Cross section transmission electron microscopy of cleaved specimen enabled to visualize nanocavities resulting from agglomeration of excess vacancies. The ion-induced damage in SiGe increases with increasing Ge fraction of the alloy. The amorphization threshold decreases and the extension of a buried amorphous layer increases for given implantation and annealing conditions. In contrast to ballistic simulations of excess defect generation where perfect local self-annihilation is assumed the concentrations of excess vacancies and excess interstitials in SiGe increase with increasing Ge fraction. The main contribution to the high excess vacancy concentration in SiGe results from the inefficient recombination of vacancies and interstitials. Th.
Scattering from a finite cylindrical shell

An asymptotic solution of scattering from a finite slender cylindrical shell is derived from the two‐variable expansions method by modifying the usual concept of secular terms. An analytical expression for the scattered far field is obtained from a superposition of sectorial spherical harmonics that have been used to describe scattering from slender bodies. The contribution of the scattered resonant pressure due to the elasticity of the material is analyzed and some numerical computations are made in monostatic and bistatic cases for rigid and elastic shells to evaluate the importance of the radiation of the resonant modes in the far field.
A note on the relation between two properties of random graphs

The $t$-e.c. and pseudo-random property are typical properties of random graphs. In this note, we study the gap between them which has not been studied well. As a main result, we give the first explicit construction of infinite families of t-e.c. graphs which are not families of best possible pseudo-random graphs.
Development and In Vitro Differentiation of Schwann Cells

Schwann cells are glial cells of the peripheral nervous system. They exist in several subtypes and perform a variety of functions in nerves. Their derivation and culture in vitro are interesting for applications ranging from disease modeling to tissue engineering. Since primary human Schwann cells are challenging to obtain in large quantities, in vitro differentiation from other cell types presents an alternative. Here, we first review the current knowledge on the developmental signaling mechanisms that determine neural crest and Schwann cell differentiation in vivo. Next, an overview of studies on the in vitro differentiation of Schwann cells from multipotent stem cell sources is provided. The molecules frequently used in those protocols and their involvement in the relevant signaling pathways are put into context and discussed. Focusing on hiPSC- and hESC-based studies, different protocols are described and compared, regarding cell sources, differentiation methods, characterization of cells, and protocol efficiency. A brief insight into developments regarding the culture and differentiation of Schwann cells in 3D is given. In summary, this contribution provides an overview of the current resources and methods for the differentiation of Schwann cells, it supports the comparison and refinement of protocols and aids the choice of suitable methods for specific applications.
Vortex reconnection rate, and loop birth rate, for a random wavefield

A time dependent, complex scalar wavefield in three dimensions contains curved zero lines, wave ‘vortices’, that move around. From time to time pairs of these lines contact each other and ‘reconnect’ in a well studied manner, and at other times tiny loops of new line appear from nowhere (births) and grow, or the reverse, existing loops shrink and disappear (deaths). These three types are known to be the only generic events. Here the average rate of their occurrences per unit volume is calculated exactly for a Gaussian random wavefield that has isotropic, stationary statistics, arising from a superposition of an infinity of plane waves in different directions. A simplifying ‘axis fixing’ technique is introduced to achieve this. The resulting formulas are proportional to the standard deviation of angular frequencies, and depend in a simple way on the second and fourth moments of the power spectrum of the plane waves. Reconnections turn out to be more common than births and deaths combined. As an expository preliminary, the case of two dimensions, where the vortices are points, is studied and the average rate of pair creation (and likewise destruction) per unit area is calculated.
Classification of Tensor Decompositions of II$_1$ Factors Associated With Poly-Hyperbolic Groups

We demonstrate von Neumann algebra arising from an icc group $\Gamma$ in Chifan's, Ioana's, and Kida's class of poly-$\mathcal{C}_\text{rss} $, such as a poly-hyperbolic group with no amenable factors in its composition series, satisfies the following rigidity phenomenon discovered in DHI16 (see also CdSS17): every tensor decomposition of the II$_1$ factor $L(\Gamma) $ must arise from direct product decomposition of $\Gamma $ by groups which are poly-$ \mathcal{C}_\text{rss}$. Through heavy usage and developments of the techniques in CdSS15, we improve the second author's and their collaborator's work in CKP14 by providing group-level criteria for determining whether a group von Neumann algebra is prime: $L(\Gamma) $ is prime precisely when the group is indecomposable as a direct product of non-amenable groups. We further demonstrate that all tensor decompositions of finite index subalgebras of $L(\Gamma) $ correspond to a splitting of $\Gamma $ as a product by groups which are also poly-$\mathcal{C}_\text{rss}$ up to commensurability.
Abelian link invariants and homology

We consider the link invariants defined by the quantum Chern–Simons field theory with compact gauge group U(1) in a closed oriented 3-manifold M. The relation of the Abelian link invariants with the homology group of the complement of the links is discussed. We prove that, when M is a homology sphere or when a link—in a generic manifold M—is homologically trivial, the associated observables coincide with the observables of the sphere S3. Finally, we show that the U(1) Reshetikhin–Turaev surgery invariant of the manifold M is not a function of the homology group only, nor a function of the homotopy type of M alone.
Fredholm determinants, Jimbo‐Miwa‐Ueno τ‐functions, and representation theory

The authors show that a wide class of Fredholm determinants arising in the representation theory of “big” groups, such as the infinite‐dimensional unitary group, solve Painlevé equations. Their methods are based on the theory of integrable operators and the theory of Riemann‐Hilbert problems. © 2002 Wiley Periodicals, Inc.
Depth cube display using depth map

We propose Depth Cube Display (DCD) method using depth map. The structure of the proposed method consists of two parts: A projection part composed of projector for generating image and a Twisted Nematic Liquid Crystal display (TNLCD) as polarization modulating device for adjusting the proper depth and a display part composed of air-spaced stack of selective scattering polarizers which make the incident light to scatter selectively as the polarization of light rays. The image from projector whose depth is determined as passing through the TN-LCD displaying depth map progresses into the stack of selective scattering polarizers and then three-dimensional image is generated. At that time, the polarization of each polarizer is set 0°, 45° and 90° sequentially, and then the incident light rays are scattered by different polarizer as the polarization of these rays. If the light ray has the polarization between those of polarizers, this light ray is scattered by multi polarizers and the image of this ray is generated on gap between polarizers. The proposed method is more simple structure and implemented easily than previous DCD method.
Fabrication of two-dimensional photonic crystal films with As2S3 by laser holography

We have fabricated 2D photonic crystal films by holographic method. Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) images show that the structures are two- dimensional in the sub-micrometric scale and the structure is perfectly ordered. The dimension in the plane of the films can be up to 50x50 mm2. Both triangular and square Lattices were made. Band structure was also simulated using the plane wave expansion method. We tried in particular to better control the fabrication process in order to have the photonic gap in the desired wavelength range.
Regular functions transversal at infinity

We generalize and complete some of Maxim's recent results on Alexan- der invariants of a polynomial transversal to the hyperplane at infinity. Roughly speaking, and surprisingly, such a polynomial behaves both topologically and al- gebraically (e.g. in terms of the variation of MHS on the cohomology of its smooth fibers), like a homogeneous polynomial.
Magnetic Core-Shell Nanoparticles Using Molecularly Imprinted Polymers for Zearalenone Determination

This paper describes the synthesis of novel molecularly imprinted magnetic nano-beads for the selective extraction (MISPE) of zearalenone mycotoxin in river and tap waters and further analysis by high-performance liquid chromatography (HPLC) with fluorescence detection (FLD). A semi-covalent imprinting approach was achieved for the synthesis of the molecularly imprinted polymers (MIP). The nanoparticles were prepared by covering the starting Fe3O4 material with a first layer of tetraethyl orthosilicate (TEOS) and then with a second layer using cyclododecyl 2-hydroxy-4-(3-triethoxysilylpropylcarbamoyloxy) benzoate. The last was used with a dual role, template and functional monomer after the extraction of the template molecule. The material was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopies (FT-IR). The solid phase extraction was optimized in all the steps: loading, washing and elution. The optimal conditions allowed the determination of zearalenone in trace levels of 12.5, 25 and 50 µg L−1 without significant differences between the fortified and found level concentrations.
Efecto de un plan de alta de enfermería para mejorar el autocuidado en los pacientes con falla cardiaca

Introducción: la falla cardiaca (FC) es una enfermedad de alto impacto en la calidad de vida de las personas. Por lo que es necesario el desarrollo de estrategias que promuevan el autocuidado desde la hospitalización y que apoyen el proceso de transición. Objetivo: determinar el efecto que tiene un plan de alta de enfermería en el nivel de autocuidado de los pacientes con FC que se encuentran hospitalizados de enero a noviembre de 2019. Metodología: ensayo clínico controlado con una muestra de 64 pacientes. Se aleatorizaron al plan de alta o al seguimiento usual. Para la medición del nivel de autocuidado se utilizó la escala europea de autocuidado con una alfa de Cronbach de 0,7. Se realizó un análisis descriptivo con tablas de frecuencias y de distribución porcentual y la prueba no paramétrica U de Mann Whitney. Resultados: antes de aplicar el plan de alta, se determinó que el 90,2 % de los pacientes del grupo control e intervención tenían un nivel bajo de autocuidado. Posterior a la aplicación del plan de alta se observó una mejoría estadísticamente significativa (p: 0,000) en el nivel de autocuidado. Conclusiones: el plan de alta tuvo un efecto beneficioso en el nivel de autocuidado gracias a sus componentes educativos, motivacionales, de refuerzo de conductas y gestión de síntomas. Este permitió que los pacientes asumieran un rol activo en la modificación de sus conductas para promover la salud.
Fluctuations of ergodic sums on periodic orbits under specification

We study the fluctuations of ergodic sums using global and local specifications on periodic points. We obtain Lindeberg-type central limit theorems in both situations. As an application, when the system possesses a unique measure of maximal entropy, we show weak convergence of ergodic sums to a mixture of normal distributions. Our results suggest decomposing the variances of ergodic sums according to global and local sources.
Influence of Mn doping on the semiconducting properties of CaCu3Ti4O12 ceramics

Comparison of impedance spectroscopy data for undoped CaCu3Ti4O12 (CCTO) and CaCu2.94Mn0. 06Ti4O12 CCMTO ceramics shows Mn doping to suppress the room temperature bulk semiconductivity of ∼0.01Scm−1 for CCTO by six orders of magnitude. The magnitude of and activation energy for bulk conduction in CCMTO are similar to those of the insulating grain boundaries in CCTO ceramics. A model to explain the suppression of the bulk conductivity in CCMTO ceramics is proposed; the grain and grain boundary regions in CCTO ceramics may consist of the same phase but with slightly different compositions.
A STATISTICAL STUDY OF ROTATIONAL VELOCITIES OF THE STARS.

The overall statistics on rotational velocities of a sample of stars are presented based on data listed in the new catalog of stellar rotational velocities. The characteristic range of equatorial rotational velocities is examined using a simple model distribution function, and it is shown that the rotational velocities of the normal stars are distributed over a relatively narrow range. Thus, the intrinsically slow rotators with rotational velocities less than 100 km/s would be seldom found among normal main sequence stars, and early Be stars would share a fairly wide range of rotational velocities with normal B stars. The distribution of observed v sin i's for some specific objects is discussed, and the dependence of mean v sin i on MK spectral type is illustrated.
Linear complementarity on simplicial cones and the congruence orbit of matrices

The congruence orbit of a matrix has a natural connection with the linear complementarity problem on simplicial cones formulated for the matrix. In terms of the two approaches -- the congruence orbit and the family of all simplicial cones -- we give equivalent classification of matrices from the point of view of the complementarity theory.
Artificial Intelligence in Technology-Enhanced Assessment: A Survey of Machine Learning

Intelligent assessment, the core of any AI-based educational technology, is defined as embedded, stealth and ubiquitous assessment which uses intelligent techniques to diagnose the current cognitive level, monitor dynamic progress, predict success and update students’ profiling continuously. It also uses various technologies, such as learning analytics, educational data mining, intelligent sensors, wearables and machine learning. This can be the key to Precision Education (PE): adaptive, tailored, individualized instruction and learning. This paper explores (a) the applications of Machine Learning (ML) in intelligent assessment, and (b) the use of deep learning models in ‘knowledge tracing and student modeling’. The paper concludes by discussing barriers involved in using state-of-the-art ML methods and some suggestions to unleash the power of data and ML to improve educational decision-making.
The Gauss map of Minimal graphs in the Heisenberg group

In this paper we study some geometric properties of surfaces in the Heisenberg group, $\mathcal{H}_{3}. $ We obtain, using the Gauss map for Lie groups, a partial classification of minimal graphs in $\mathcal{H}_{3}. $ We also proof the non existence of umbilical surfaces in $\mathcal{H}_{3}. $
Icosahedron, exceptional singularities and modular forms

We find that the equation of $E_8$-singularity possesses two distinct symmetry groups and modular parametrizations. One is the classical icosahedral equation with icosahedral symmetry, the associated modular forms are theta constants of order five. The other is given by the group $\text{PSL}(2, 13)$, the associated modular forms are theta constants of order $13$. As a consequence, we show that $E_8$ is not uniquely determined by the icosahedron. This solves a problem of Brieskorn in his ICM 1970 talk on the mysterious relation between exotic spheres, the icosahedron and $E_8$. Simultaneously, it gives a counterexample to Arnold's $A, D, E$ problem, and this also solves the other related problem on the relation between simple Lie algebras and Platonic solids. Moreover, we give modular parametrizations for the exceptional singularities $Q_{18}$, $E_{20}$ and $x^7+x^2 y^3+z^2=0$ by theta constants of order $13$, the second singularity provides a new analytic construction of solutions for the Fermat-Catalan conjecture and gives an answer to a problem dating back to the works of Klein.
Parameter sampling capabilities of sequential and simultaneous data assimilation: I. Analytical comparison

We assess the parameter sampling capabilities of some Bayesian, ensemble-based, joint state-parameter (JS) estimation methods. The forward model is assumed to be non-chaotic and have nonlinear components, and the emphasis is on results obtained for the parameters in the state-parameter vector. A variety of approximate sampling methods exist, and a number of numerical comparisons between such methods have been performed. Often, more than one of the defining characteristics vary from one method to another, so it can be difficult to point out which characteristic of the more successful method in such a comparison was decisive. In this study, we single out one defining characteristic for comparison; whether or not data are assimilated sequentially or simultaneously. The current paper is concerned with analytical investigations into this issue. We carefully select one sequential and one simultaneous JS method for the comparison. We also design a corresponding pair of pure parameter estimation methods, and we show how the JS methods and the parameter estimation methods are pairwise related. It is shown that the sequential and the simultaneous parameter estimation methods are equivalent for one particular combination of observations with different degrees of nonlinearity. Strong indications are presented for why one may expect the sequential parameter estimation method to outperform the simultaneous parameter estimation method for all other combinations of observations. Finally, the conditions for when similar relations can be expected to hold between the corresponding JS methods are discussed. A companion paper, part II (Fossum and Mannseth 2014 Inverse Problems 30 114003), is concerned with statistical analysis of results from a range of numerical experiments involving sequential and simultaneous JS estimation, where the design of the numerical investigation is motivated by our findings in the current paper.
Mean Width of a Regular Cross-Polytope

The expected range of a sample of n+1 normally distributed variables is known to be related to the mean width of a regular n-simplex. We show that the expected maximum mu_n of a sample of n half-normally distributed variables is related to the mean width of a regular n-crosspolytope. Both of these relations have mean square counterparts. An expression for mu_5 is found and is believed to be new.