Miracle-dz/UniFAR-FTUs huggingface dataset:
Experimental demonstration of the van Cittert-Zernike theorem for random electromagnetic fields

In scalar coherence theory, the van Cittert-Zernike theorem plays an importance role for studying the propagation processes of partially coherent fields. In the past few years, a lot of work has been done to describe an extension of the van Cittert-Zernike theorem in terms of the 2×2 matrix to examine coherence and polarization properties of the field generated by a partially polarized incoherent electromagnetic beam. In this paper, we would like to experimentally demonstrate the unified theory of coherence and polarization of random electromagnetic beams by a modified radial shearing interferometer, which may be regarded as a tensor version of van Cittert-Zernike theorem. The experimental results show that the mutual intensity matrix of the electromagnetic field produced by a polarized incoherent source increases on propagation whereas the degree of the polarization remains unchanged.
Gasdynamics in interacting and merging galaxies

A three-dimensional model is developed for gas clouds orbiting in the gravitational potential of a galaxy which, at some later time, is perturbed by the gravitational influence of another galaxy. As the strength of the interaction increases, the interstellar medium becomes more disturbed. The clouds collide at an increased rate and with larger velocities, so that the fraction of collisions which disrupt the clouds rises rapidly as the strength of the interaction increases. On the other hand, no large increases in the rate at which massive clouds are built up are found. Since interacting galaxies are observed to have star formation efficiencies which are about five times higher than those in isolated galaxies, it is concluded that the star formation induced by the interaction of two galaxies is related to the high-velocity, disruptive cloud-cloud collisions. 46 refs.
Two-sample wilcoxon power over the pearson system and comparison with the t-test

The present study has as its object an accurate evaluation of the power of the two-sample equal sample size Wilcoxon test over an extensive practical range of uismnmioriv The method is thai o! a large Monte Carlo study over the Pearson ay item of dmnbuUoiia. β1 = 0.0(0.4)2.0, β2 = 1.4(0.4)7.8 (negative and positive skewness) and equal sample sizes N = 5(5)30. The power is evaluated for two values of the noncentrahty parameter △ (values which produce powers of 0.50 and 0.95 for the corresponding r-test under normality) and these probabilities are evaluated from 40,000 generated values of the test statistic. Since the ingredients of this study are identical to those of a similar earlier study of the t-test, a comparison of the power of the Wilcoxon and the t-test is provided to determine the range of the Pearson system in which the power function of one test is superior to that of the other. The stutly is restricted to equal sample size tests and the results may not apply to more than moderate departures fr.
Surface scattering plasmon resonance fibre sensors: demonstration of rapid influenza A virus detection

The management of threats such as pandemics and explosives, and of health and the environment requires the rapid deployment of highly sensitive detection tools. Sensors based on Surface Plasmon Resonance (SPR) allow rapid, labelfree, highly sensitive detection, and indeed this phenomenon underpins the only label-free optical biosensing technology that is available commercially. In these sensors, the existence of surface plasmons is inferred indirectly from absorption features that correspond to the coupling of light to the surface plasmon. Although SPR is not intrinsically a radiative process, under certain conditions the surface plasmon can itself couple to the local photon states, and emit light as first described byKretschmann. Here we show that by collecting and characterising this re-emitted light, it is possible to realise new SPR sensing architectures that are more compact, versatile and robust than existing approaches. This approach addresses existing practical limitations associated with current SPR technologies, including bulk, cost and calibration. It is applicable to a range of SPR geometries, including optical fibres, planar waveguides and prism configurations, and is in principle capable of detecting multiple analytes simultaneously. Moreover, this technique allows to combine SPR sensing and fluorescence sensing into a single platform which has never been demonstrated before and consequently use these two methods for a more reliable diagnostic. As an example, this approach has been used to demonstrate the rapid detection of the seasonal influenza virus.
The effect of reconnection upon the linkage and interior structure of magnetic flux tubes

The topological properties of a magnetic field are interpreted in terms of magnetic helicity. The total helicity of a collection of flux tubes arises from the linking of flux tubes with one another (mutual helicity) and the internal magnetic structure of each flux tube (self-helicity). Reconnection changes the topology and magnetic connectivity of flux tubes. This can also be viewed as a redistribution of self- and mutual helicities. If total magnetic helicity is approximately conserved, it is possible to put quantitative limits upon the changes in self- and mutual helicities. This can be interpreted as the change in magnetic flux tube linkage (due to reconnection) and amount of twist present in the reconnected flux tubes. The implications for reconnection in the terrestrial magnetosphere are also discussed.
Localized Pulsating Solutions of the Generalized Complex Cubic-Quintic Ginzburg-Landau Equation

We study the dynamics of the localized pulsating solutions of generalized complex cubic-quintic Ginzburg-Landau equation (CCQGLE) in the presence of intrapulse Raman scattering (IRS). We present an approach for identification of periodic attractors of the generalized CCQGLE. Using ansatz of the travelling wave and fixing some relations between the material parameters, we derive the strongly nonlinear Lienard-Van der Pol equation for the amplitude of the nonlinear wave. Next, we apply the Melnikov method to this equation to analyze the possibility of existence of limit cycles. For a set of fixed parameters we show the existence of limit cycle that arises around a closed phase trajectory of the unperturbed system and prove its stability. We apply the Melnikov method also to the equation of Duffing-Van der Pol oscillator used for the investigation of the influence of the IRS on the bandwidth limited amplification. We prove the existence and stability of a limit cycle that arises in a neighborhood of a homoclinic trajectory of the corresponding unperturbed system. The condition of existence of the limit cycle derived here coincides with the relation between the critical value of velocity and the amplitude of the solitary wave solution (Uzunov, 2011).
Boussinesq's problem for a flat-ended cylinder

1. In a recent paper(1) expressions were found for the elastic stresses produced in a semi-infinite elastic medium when its boundary is deformed by the pressure against it of a perfectly rigid body. In deriving the solution of this problem—the ‘Boussinesq’ problem—it was assumed that the normal displacement of a point within the area of contact between the elastic medium and the rigid body is prescribed and that the distribution of pressure over that area is determined subsequently. The solutions for the special cases in which the free surface was indented by a cone, a sphere and a flat-ended cylindrical punch were derived, but no attempt was made to give a full account of the distribution of stress in the interior of the medium in any of these cases.
The spindle-like galaxies UGC 7576 and II Zw 73

On a cartographie UGC 7576 et IIZw73 dans la raie a 21 cm de l'hydrogene neutre. Les champs des vitesses dans les deux objets soutiennent l'identification des composantes externes a des anneaux vus de profil, en rotation differentielle. Les rapports masse d'hydrogene-luminosite optique dans ces composantes sont exceptionnellement grands. Les anneaux semblent s'etre formes dans un passe relativement recent
K-tree: a height balanced tree structured vector quantizer

We describe a clustering algorithm for the design of height balanced trees for vector quantisation. The algorithm is a hybrid of the B-tree and the k-means clustering procedure. K-tree supports on-line dynamic tree construction. The properties of the resulting search tree and clustering codebook are comparable to that of codebooks obtained by TSVQ, the commonly used recursive k-means algorithm for constructing vector quantization search trees. The K-tree algorithm scales up to larger data sets than TSVQ, produces codebooks with somewhat higher distortion rates, but facilitates greater control over the properties of the resulting codebooks. We demonstrate the properties and performance of K-tree and compare it with TSVQ and with k-means.
Flying height measurement considering the effects of the slider-disk interaction

As technology moves to a mechanical head-disk spacing of 4-8 nm for the recording density beyond 100 Gb/in/sup 2/, new testing methodology becomes necessary to achieve both high sensitivity in flying height measurement and accurate characterization of slider-lube-disk interaction. This paper reports a polarization intensity interferometer which retains high sensitivity in fly-height measurement even when the slider-disk spacing is down to nanometer level. The setup can also study the effect of slider-lube-disk interaction on the flying performance of the slider. This is achieved by covering the commercial glass disk substrate with a layer of carbon overcoat and a layer of lubricant which are same as those used in the actual disk media. Both simulation and experimental investigations were conducted and the results agree well with each other. Results also indicate that it is important to take the slider-disk interaction into account in the flying height measurement of the nanometer spaced head-disk interface.
Generation and transportation mechanisms for two-dimensional hole gases in GaN/AlGaN/GaN double heterostructures

The electrical properties of two-dimensional hole gases (2DHGs) in GaN/AlGaN/GaN double heterostructures were investigated. The layers were grown on sapphire substrates and a high-quality bulk GaN substrate. The coexistence of 2DHG and 2D electron gases on both sides of the AlGaN layer was confirmed by Hall effect measurements at 80–460 K. It was also verified that the 2DHGs were generated by negative polarization at the undoped GaN/AlGaN interface, which did not have a doped Mg acceptor. It was also demonstrated that the 2DHG density could be controlled by varying the AlGaN layer thickness and was inversely related to the 2DHG mobility. The measured relation indicated that the 2DHG mobility is mainly limited by phonon scatterings at around room temperature. As a result, the maximum 2DHG mobility of 16 cm2/Vs at 300 K was achieved with a density of 1 × 1013 cm−2.
Push-pull mode magnetostrictive/piezoelectric laminate composite with an enhanced magnetoelectric voltage coefficient

A magnetoelectric (ME) laminate composite consisting of a symmetric longitudinally poled piezoelectric Pb(Mg1∕3Nb2∕3)O3–PbTiO3 crystal and two longitudinally magnetized magnetostrictive Tb1−xDyxFe2 layers has been developed that has a notably superior ME voltage coefficient, relative to previous laminate configurations. The symmetric nature of the longitudinally poled piezoelectric layer allows for operation in a push-pull mode that optimizes elastic coupling between layers. Our small laminate has a giant ME voltage coefficient of ∼1.6V∕Oe at low frequencies, a significant enhancement of this coefficient to ∼20V∕Oe under resonance drive, and an exceptional low-level magnetic field sensitivity of ∼10−12T at f=f0.
From the hyper-Bessel operators of Dimovski to the generalized fractional calculus

In 1966 Ivan Dimovski introduced and started detailed studies on the Bessel type differential operators B of arbitrary (integer) order m ≥ 1. He also suggested a variant of the Obrechkoff integral transform (arising in a paper of 1958 by another Bulgarian mathematician Nikola Obrechkoff) as a Laplace-type transform basis of a corresponding operational calculus for B and for its linear right inverse integral operator L. Later, the developments on these linear singular differential operators appearing in many problems of mathematical physics, have been continued by the author of this survey who called them hyper-Bessel differential operators, in relation to the notion of hyper-Bessel functions of Delerue (1953), shown to form a fundamental system of solutions of the IVPs for By(t) = λy(t). We have been able to extend Dimovski’s results on the hyper-Bessel operators and on the Obrechkoff transform due to the happy hint to attract the tools of the special functions as Meijer’s G-function and Fox’s H-function to handle successfully these matters. These author’s studies have lead to the introduction and development of a theory of generalized fractional calculus (GFC) in her monograph (1994) and subsequent papers, and to various applications of this GFC in other topics of analysis, differential equations, special functions and integral transforms.Here we try briefly to expose the ideas leading to this GFC, its basic facts and some of the mentioned applications.
An hydrodynamical model of the barred galaxy NGC 5850

We present the results of hydrodynamical model calculations of the barred galaxy NGC 5850 and compare to HI observations. The models assume a mass distribution for the galaxy which was obtained from photometrical I band observations. A pure bar perturbation model reproduces the HI observations in the inner 80 00 of the galaxy. The reproduced morphological features are: the central gas concentration, the hole of gas in the bar region and the ring of HI located at the end of the bar. The spiral arms are not reproduced. The best model has the co-rotation located at 90 00 and the mass of the bulge, bar, disk and halo are respectively: 4:7 10 9 M, 4:6 10 9 M ,4 :9 10 10 M and 6:93 10 10 M.
Vortex velocity laws to I-V data for flat superconductors

A vortex-density model for type-II superconductors is used to study the transport current in a strip in flux-flow conditions. Flux pinning is incorporated using a stick-slip vortex velocity law. Current and vortex density profiles are calculated, and the effect of applied magnetic fields and pinning strength is analysed. The I-V characteristics are determined and related to the local vortex velocity law. Initial comparisons of the results with experimental data show good agreement.
On conjugate functions, subgradients, and directional derivatives of a class of optimality criteria in experimental design

We consider the problem of optimum experimental design. Minimize where Ω is a set (of admissible information matrices) included in the space Snof symmetric matrices of order n-by-n. [n an attempt to deal in a unified way with the different types fo optimality criterion found in the literature, we introduce the model
A New Basis Implementation for a Mixed Order Boundary Value ODE Solver

The numerical approximation of mixed order systems of multipoint value ordinary differential equations by collocation requires appropriate representation of the piecewise polynomial solutions. B-splines were originally implemented in the general purpose code COLSYS, but better alternatives exist. One promising alternative as proposed by Osborne and discussed by Ascher, Pruess and Russell. In this paper we analyze the performance of the latter solution representation for cases not previously covered, where the mesh is not necessarily dense. This analysis and other considerations have led us to implement a basis replacement in COLSYS and we discuss some implementation details. Numerical results are given which demonstrate the improvement in performance of the code.
A modiﬁcation of WKB method for fractional differential operators of Schrödinger’s type

In this paper, we were concerned with the description of the singularly perturbed differential equations within the scope of fractional calculus. However, we shall note that one of the main methods used to solve these problems is the so-called WKB method. We should mention that this was not achievable via the existing fractional derivative deﬁnitions, because they do not obey the chain rule. In order to accom-modate the WKB to the scope of fractional derivative, we proposed a relatively new derivative called the local fractional derivative. By use of properties of local fractional derivative, we extend the WKB method in the scope of the fractional differential equation. By means of this extension, the WKB analysis based on the Borel resummation, for fractional differential operators of WKB type are investigated. The convergence and the Mittag-Lefﬂer stability of the proposed approach is proven. The obtained results are in excellent agreement with the existing ones in open literature and it is shown that the present approach is very effective and accurate. Furthermore, we are mainly interested to construct the solution of fractional Schrödinger equation in the Mittag-Lefﬂer form and how it leads naturally to this semi-classical approximation namely modiﬁed WKB .
Vlasov fluid stability of the m=0 mode in a skin current Z pinch

The m=0 stability of a Z pinch confined by a skin current has been studied using the Vlasov fluid model. A significant reduction in growth rate compared to ideal magnetohydrodynamics (MHD) is found. An exact analytic solution can be obtained at large ka (k is the axial wavenumber and a is the pinch radius). In this limit the Vlasov fluid growth rate (normalized to the radial ion thermal transit time) saturates to the value 0.5 (π)1/2, in contrast to the ideal MHD growth rate, which increases without limit as (k)1/2.
Designing an object-oriented architecture for the finite element simulation of structural elements

This paper reports the development of an architecture and software implementation of the library of classes for the finite-element analysis of problems in the theory of elasticity with an open-source code. The practical necessity of such systems is due to the fact that in modern equipment there are new types of materials whose structural elements' calculation has certain features. As a result, it is necessary to update the relevant scientific software or even devise a new one. A flexible software architecture is designed to reduce the time and complexity of such updates. Existing implementations of the method of finite elements with open source have been analyzed: it was revealed that there are no systems aimed at the most flexible and user-friendly architecture. The system of abstract classes proposed in the current work corresponds to known SOLID principles of object-oriented design and makes it possible to scale the already developed analysis program for new tasks in an easy and understandable way. To test the quality of the developed system from the point of view of software engineering, the maintainability index and cyclomatic complexity code metrics were used. The values of these metrics for the modules of the PyFEM system core vary in the following ranges: from 1 to 18 for the maintainability index, and from 22 to 100 for cyclomatic complexity. PyFEM testing was performed on the task of determining the stressed-strained state of the turbine rotor blade. Due to the ease of implementation, it was possible to build a set of effective and intuitive classes that make it possible to solve numerically the static and dynamic problems in the theory of elasticity. The developed class library can be used in the development of both universal and specialized software designed to analyze multiphysics problems.
Motion correction in spatial frequency domain imaging; optical property determination in pigmented lesions

Background and Objective: Spatial Frequency Domain Imaging (SFDI) is a non-contact wide-field optical imaging technology currently being used to study the optical properties and chromophore concentrations of in-vivo malignant melanomas and benign pigmented lesions. Our objective is to develop a motion correction procedure in order to assess the concerns of subject-motion related variables during clinical measurements. Study Design/Materials and Methods: SFDI motion-correction is a two-part procedure which utilizes a fiduciary marker and canny-edge detection in order to reposition and align the frame-to-frame regions-of-interest (ROI). Motioninduced phase-shifts are subsequently sampled before the entire image-set is processed by a modified demodulation formula. By comparing the results of the adjusted processing method with data gathered from the current non-corrected method, we were able to systematically characterize the impact of motion variables on SFDI measurements. Results: Motion-corrected SFDI data from moving phantom measurements and clinical patient measurements showed up to 84.58% decrease in absorption (μa) variance and up to 92.63% decrease in reduced-scattering (μs') variance. Stationary phantom test-measurements showed almost no difference between motion corrected and standard processing. Conclusion: SFDI motion correction is necessary for obtaining high-fidelity in-vivo optical property measurements of pigmented lesions in a clinical setting.
Moving Object Detection Based on Improved Variational GAC Model

In view of the detection of moving object in video sequence, the traditional moving object detection algorithms are researched. The paper presents a new algorithm for object detection based on initial contour and improved variational GAC model. First, this method built up background model utilizing Gaussian mixture model and background subtraction to extract initial contour of the object; taking initial contour as initial value of curve evolution. Then, an improved restriction item is introduced into variational GAC vector model, the proposed restriction item that is a nonlinear hear equation with normalized diffusion rate, therefore re-initialization procedure of level set function is completely eliminated. Iteration number of curve evolution and run time is reduced. The experimental show that accurate contour of moving object is got and this algorithm is effective and feasible in real video environment.
Modélisation des prix de quatre types de vraquiers d'occasion : une approche structurelle autorégressive par

The goal of this paper is to model the prices of second-hand bulkers in the scope of forecasting them. This speculative activity is particularly important given the amounts of resources involved in ship transactions which, generally, generate more resources than shipping operations themselves. To achieve this, a structural model based on prices of transported bulk materials, the interest rate and specific freight rates, is used to model the price of second-hand bulkers. To this are added some lags of the dependent variable in order to satisfy econometric constraints. Even though the results are preliminary, they seem in-sink with the current literature and might even be a little innovative.
Inference of the magnetic field in spicules from spectropolarimetry of He I D$_\mathsf{3}$

We present observations of spicules in the $\ion{He}{i}$ D 3 line with full-Stokes spectropolarimetry, which were done with the Advanced Stokes Polarimeter at the Dunn Solar Telescope of the Sacramento Peak Observatory. The line profiles appear to be significantly broadened by non-thermal processes, which we interpret using the hypothesis of a distribution of velocities inside the spicule. The possibility of inferring the magnetic field in those conditions is tested on synthetic data, and the results are generalized to the interpretation of the observed data. We conclude that the magnetic field is aligned with the visible structure of the spicule, with strengths above $30\,\rm G$ in some cases (for heights between 3000 and $5000\,\rm km$ above the photosphere).