Miracle-dz/UniFAR-FTUs huggingface dataset:
Propagation of a neutrino in a homogeneous magnetic field

A neutrino, although it has no electric charge, can interact with a magnetic field by virtue of self-energy processes in which the virtual particles are charged. In this note, we examine the one-loop correction to the neutrino propagator in the presence of a homogeneous magnetic field in the context of the standard Weinberg-Salam model for leptons, using a technique introduced by Sapirstein.
Colour‐differential interferometry for the observation of extrasolar planets

We present the high angular resolution technique of colour-differential interferometry for direct detection of extrasolar giant planets (EGPs). The measurement of differential phase with long-baseline ground-based interferometers in the near-infrared could allow the observation of several hot giant extrasolar planets in tight orbit around the nearby stars, and thus yield their low- or mid-resolution spectroscopy, complete orbital data set and mass. Estimates of potentially achievable signal-to-noise ratios are presented for a number of planets already discovered by indirect methods. The limits from the instrumental and atmospheric instability are discussed, and a subsequent observational strategy is proposed.
Infrared Space Observatory Long Wavelength Spectrometer Observations of C+ and O0 Lines in Absorption toward Sagittarius B2

High spectral resolution Fabry-Pérot observations of the [O I] 63.2 and 145.5 μm and [C II] 157.7 μm fine-structure lines are presented for the center of the Sagittarius B2 complex (Sgr B2). The data were obtained with the Long Wavelength Spectrometer on board the Infrared Space Observatory (ISO). Both the [O I] 63.2 μm and the [C II] 157.7 μm lines are detected in absorption. The upper state level of atomic oxygen at 145.5 μm is in emission. Whereas the [O I] 63.2 μm line is seen in absorption over the entire wavelength range -200 to 100 km s-1, the [C II] 157.7 μm line displays a more complex profile: absorption occurs at velocities less than 20 km s-1, and emission comes from the Sgr B2 complex at velocities greater than 20 km s-1. Using observations of the CO isotopes and of the H I lines, absorption components can be associated with many clouds along the Sgr B2 line of sight. From these data, we were able to disentangle three different layers that contain atomic oxygen. These layers, as predicted by photodissociation region models, are characterized by different forms of carbon in the gas phase, i.e., the C+ external layer, the C+ to C0 transition, and the CO internal layer. We derive lower limits for the column densities of atomic carbon and oxygen of the order of ~1018 cm-2 and 3 × 1019 cm-2, respectively. An O0/CO ratio of around 2.5 is computed in the internal cores of the clouds lying along the line of sight, which means that ~70% of gaseous oxygen is in the atomic form and not locked into CO. The fact that the [C II] 157.7 μm line is detected in absorption implies that the main cooling line of the interstellar medium can be optically thick, especially in the direction of large star-forming complexes or in the nuclei of galaxies. This could partially account for the deficiency in the [C II] 157.7 μm line that recently has been found toward infrared-bright galaxies in ISO data.
Blue disk galaxies in the Coma cluster: analogs to z=0.5 cluster members?

On presente les observations spectroscopiques de sept galaxies disques tres bleues de l'amas Coma. On compare les intensites des raies de Balmer de ces galaxies a celles des galaxies bleues de 3C 295 et on montre qu'il est possible qu'on soit actuellement en train d'observer dans l'amas de Coma le meme phenomene que celui qui s'est produit dans l'amas 3C 295 il y a plusieurs milliards d'annees
Transparent p-type SnOx thin film transistors produced by reactive rf magnetron sputtering followed by low temperature annealing

P-type thin-film transistors (TFTs) using room temperature sputtered SnOx (x<2) as a transparent oxide semiconductor have been produced. The SnOx films show p-type conduction presenting a polycrystalline structure composed with a mixture of tetragonal β-Sn and α-SnOx phases, after annealing at 200 °C. These films exhibit a hole carrier concentration in the range of ≈1016–1018 cm−3; electrical resistivity between 101–102 Ω cm; Hall mobility around 4.8 cm2/V s; optical band gap of 2.8 eV; and average transmittance ≈85% (400 to 2000 nm). The bottom gate p-type SnOx TFTs present a field-effect mobility above 1 cm2/V s and an ON/OFF modulation ratio of 103.
Flare loop radiative hydrodynamics. IV. Dynamic evolution of unstable semiempirical loop models

The evolution of the unstable solar atmosphere into the nonlinear phase, in response to various perturbations, is followed. The initial dynamic evolution of the atmosphere follows the predictions of linear stability analysis. In the nonlinear phase, rapid changes are confined to the transition region; these changes are manifested as a propagation of the transition region through the plasma, i.e., chromospheric evaporation or condensation. Global evolution therefore proceeds on the coronal conductive time scale. The rate of propagation of the transition region is determined by the imbalance between the energy supplied by thermal conduction from the corona and radiative cooling within the transition region itself. Flow velocities in the lower corona during evaporation or condensation are, in the cases studied, of order 3 km/s. The observed dynamic evolution is consistent with the existence of relatively long-lived coronal loops whose brightnesses vary on the evaporative time scale.
Prospects for Dynamical Prediction of Meteorological Drought

AbstractThe prospects for U.S. seasonal drought prediction are assessed by diagnosing simulation and hindcast skill of drought indicators during 1982–2008. The 6-month standardized precipitation index is used as the primary drought indicator. The skill of unconditioned, persistence forecasts serves as the baseline against which the performance of dynamical methods is evaluated. Predictions conditioned on the state of global sea surface temperatures (SST) are assessed using atmospheric climate simulations conducted in which observed SSTs are specified. Predictions conditioned on the initial states of atmosphere, land surfaces, and oceans are next analyzed using coupled climate-model experiments. The persistence of the drought indicator yields considerable seasonal skill, with a region’s annual cycle of precipitation driving a strong seasonality in baseline skill. The unconditioned forecast skill for drought is greatest during a region’s climatological dry season and is least during a wet season. Dynamical .
The magnetic field and wind confinement of θ1 Orionis C

We report the detection, through spectropolarimetric observations, of a strong dipolar magnetic field of presumably fossil origin at the surface of the very young O star theta (1) Ori C. The Stokes V signatures we detect are variable with time, the variations being consistent with rotational modulation. A detailed modelling of our observations indicates that this dipole field has an intensity of 1.1+/-0.1 kG and is inclined at 42degrees+/-6degrees with respect to the rotation axis (assumed to be inclined at 45degrees to the line of sight). We find, in particular, that the positive magnetic pole comes closest to the observer when the variable Halpha emission component observed on this star reaches maximum strength. This discovery represents the first definite detection of a magnetic field in an O star, as well as the first detection of a fossil field in a very young star.We also investigate in this paper the magnetic confinement of the radiatively driven wind of theta (1) Ori C in the context of the magnetically confined wind-shock model of Babel & Montmerle. In the case of theta (1) Ori C, this model predicts the formation of a large magnetosphere (extending as far as 2-3R *), consisting of a very hot post-shock region (with temperatures in excess of 10 MK and densities of about 10(10) -10(11) cm(-3) ) generated by the strong collision of the wind streams from both stellar magnetic hemispheres, as well as a dense cooling disc forming in the magnetospheric equator. We find that this model includes most of the physics required to obtain a satisfactory level of agreement with the extensive data sets available for theta (1) Ori C in the literature (and, in particular, with the recent X-ray data and the phase-resolved spectroscopic observations of ultraviolet and optical wind lines) provided that the mass-loss rate of theta (1) Ori C is at least 5 times smaller than that predicted by radiatively driven wind models. We finally show how new observations with the XMM or Chandra spacecraft could help us constrain this model much more tightly and thus obtain a clear picture of how magnetic fields can influence the winds of hot stars.
Bayesian moving object detection in dynamic scenes using an adaptive foreground model

Accurate detection of moving objects is an important step in stable tracking or recognition. By using a nonparametric density estimation method over a joint domain-range representation of image pixels, the correlation between neighboring pixels can be used to achieve high levels of detection accuracy in the presence of dynamic background. However, color similarity between foreground and background will cause many foreground pixels to be misclassified. In this paper, an adaptive foreground model is exploited to detect moving objects in dynamic scenes. The foreground model provides an effective description of foreground by adaptively combining the temporal persistence and spatial coherence of moving objects. Building on the advantages of MAP-MRF (the maximum a posteriori in the Markov random field) decision framework, the proposed method performs well in addressing the challenging problem of missed detection caused by similarity in color between foreground and background pixels. Experimental results on real dynamic scenes show that the proposed method is robust and efficient.
Free rate‐independent elastoplastic equations

New rate‐independent finite elastoplastic equations are proposed in unified forms applicable to all loading‐unloading cases. A departure from the classical elastoplastic equations is that these new equations are not subjected to and hence free from the usual extrinsic restrictive conditions, including the yield condition as well as the loading‐unloading conditions. Such free equations are of Eulerian rate type and assume the same smooth form for all possible stresses and for all strain rates. It is demonstrated that the essential representative features of finite elastoplastic deformations, namely, the yield behavior and the loading‐unloading behavior in the traditional sense, may be derived from and hence naturally incorporated as intrinsic physical characteristics into the free elastoplastic equations proposed in a more realistic sense and, in particular, the classical notions characterizing these features are found to exhibit novel, perhaps more profound physical meanings in the new equations. Furthermore, the strong discontinuity in tangent moduli at transition from elastic to plastic state, involved in the traditional formulation, is shown to be replaced by a smooth transition. Implications are discussed in respects of constitutive implications and numerical treatment.
The structure of molten sodium chloride

The structure of molten sodium chloride has been investigated by applying the technique of neutron diffraction to isotopically enriched samples. The three partial structure factors relating to Na-Na, Cl-Cl, and Na-Cl correlations have been successfully extracted from the data. Some general conclusions about the structure of molten sodium chloride are made and the relationship between the present work and earlier theoretical studies is discussed.
Theoretical analysis and comparison of SWIR active imaging detectors

This paper is a theoretical analysis and a comparison of imaging sensor technologies compatible with active imaging applications that operate in the SWIR band. Two types of sensors are commonly used: detectors with gain induced by internal photoelectron multiplication process (HgCdTe APD FPA and InGaAs/InP TE EBCMOS) and detectors without internal gain (InGaAs FPA). Active imaging requires a sensitive high-speed sensor able to detect a short, weak pulse backscattered from a target. The goal is to reach a sensitivity defined by a NEPh of 10 photons rms, and a SNR of 5-10 for an input signal of 100-200 photons/pulse/pixel. We demonstrate that the HgCdTe APD FPA detector with gain is intrinsically the best technology to fulfill the aforementioned requirements. In comparison, the InGaAs/InP TE EBCMOS also works well but suffers from limited quantum efficiency, less than 30% at the most. The main advantage of detectors with internal gain is their potential to amplify the laser signal above the readout noise level, under the condition that the excess noise factor induced by the multiplication process remains close to 1. The InGaAs FPA detector without gain is lower cost, however it exhibits a NEPh of around one order of magnitude higher and a SNR 3 to 6 times lower. At a system level, a more powerful laser will compensate for this difference but will also increase the cost. In conclusion to the tradeoff regarding performance versus cost, each specific system need should determine the best matched technology.
Consonantal context and experience effects on American L2‐learners’ perception of French vowels

According to Best’s [Best, C. T. (1994). ‘‘The emergence of native‐language phonological influence in infants: A perceptual assimilation model,’’ in The Development of Speech Perception: The Transition from Speech Sounds to Spoken Words, edited by J. Goodman & H. C. Nusbaum (MIT Press, Cambridge, MA); Best, C. T. (1995) ‘‘A direct realist view of cross‐language speech perception,’’ in Speech Perception and Linquistic Experience Issues in Cross‐Language Research, edited by W. Strange (York Press, Baltimore, MD)] Perceptual Assimilation Model (PAM), listeners’ perceptual assimilation of unfamiliar speech sounds predicts their discrimination accuracy of these sounds. This study applied the PAM to second‐language (L2) learners. Three groups of American English (AE) listeners performed a perceptual assimilation (PA) task involving Parisian French (PF) vowels /y‐œ ‐u‐o‐i‐e‐a/ and a categorial discrimination task involving French front versus back rounded pairs /y‐u/, /y‐o/, /œ ‐o/, /œ ‐u/, front rounded versus .
Masers as probes of supersonic turbulence

Abstract A possible intimate connection between astrophysical masers in regions of star formation and turbulence has been a subject of increasing interest during the last two decades. Evidence for the presence of a residual turbulent component in the observed expansion and rotation of clusters of water masers was shown by multi-epoch VLBI maps. The water maser hot spots demonstrate self-similar (fractal) spatial clustering and a power-law two-point velocity correlation function similar to that of incompressible turbulence – with the power index close to “Kolmogorov's” 1/3. The possibility of using maser sources for studying supersonic turbulence critically depends on whether the observed hot spots are an integral effect of radiative transfer over a large distance, comparable to the size of the whole maser source, or whether they are compact local physical objects, such as small random shocks, in which the mechanical energy of turbulence dissipates. If the latter hypothesis is correct, the compact and bright maser hot spots may be excellent local probes of the spatial and kinematic structure of supersonic turbulence. Observational and theoretical arguments for and against these hypotheses are discussed and the first quantitative results about supersonic turbulence obtained by statistical analysis of maser sources are presented in this review.
Non-conservative robust Kalman filtering using a noise corrupted measurement matrix

A new class of robust Kalman filtering problem is addressed for time-varying linear systems. It is assumed that a noise corrupted observation of the deterministic measurement matrix be only available for filtering. Aside from the existing robust Kalman filters (RKFs), the design objective of the proposed RKF is set to achieve the quasi-optimal performance in spite of using the noise contaminated measurement matrix. By solving the stochastic minimisation problem of an indefinite quadratic form, which is an approximated version of the optimal Kalman filtering cost, the suggested RKF recursion is derived. It is also shown that the proposed RKF becomes a unique minimum of the given indefinite cost when the estimation error Gramian matrix is positive definite. The statistical properties of the proposed RKF are analysed by investigating its strong consistency and the asymptotic distribution of estimation errors. Based on these analysis results, the quasi-optimality of the proposed filter is assessed in the sense of least mean-squares estimation. The frequency estimation problem of a noisy sinusoidal signal is provided to verify the presented theory and to demonstrate the effectiveness of the proposed scheme.
Mixed convection in a periodically heated channel

Mixed convection in a channel with flow driven by a pressure gradient and subject to spatially periodic heating along one of the walls has been studied. The pattern of the heating is characterized by the wavenumber ${\it\alpha}$ and its intensity is expressed in terms of the Rayleigh number $\mathit{Ra}_{p}$ . The primary convection has the form of counter-rotating rolls with the wavevector parallel to the wavevector of the heating. The resulting net heat flow between the walls increases proportionally to $\mathit{Ra}_{p}$ but the growth saturates when $\mathit{Ra}_{p}=O(10^{3})$ . The most effective heating pattern corresponds to ${\it\alpha}\approx 1$ , as this leads to the most intense transverse motion. The primary convection is subject to transition to secondary states with the onset conditions depending on ${\it\alpha}$ . The conditions leading to transition between different forms of secondary motion have been determined using the linear stability theory. Three patterns of secondary motion may occur at small Reynolds numbers $\mathit{Re}$ , i.e. longitudinal rolls, transverse rolls and oblique rolls, with the critical conditions varying significantly as a function of ${\it\alpha}$ . An increase of ${\it\alpha}$ leads to the elimination of the longitudinal rolls and, eventually, to the elimination of the oblique rolls, with the transverse rolls assuming the dominant role. For large ${\it\alpha}$ , the transition is driven by the Rayleigh–Bénard mechanism; while for ${\it\alpha}=O(1)$ , the spatial parametric resonance dominates. The global flow characteristics are identical regardless of whether the heating is applied at the lower or the upper wall.
Introducing mass balancing theorem for network flow maximization

Article history: Received 27 March 2012 Received in revised format 31 May 2012 Accepted June 8 2012 Available online 9 June 2012 Maximization of flow through the network is required in many practical applications such as water supply flow networks, Oil and Gas flow networks, and transportation networks etc. In this paper a new theorem is presented that has direct application on maximization of flow through the network. This theorem suggests that the maximization of network flow can be achieved by visiting only unbalanced nodes rather than the whole network. Therefore based on this theorem a method is developed that maximizes flow thorough the network by visiting only unbalanced nodes. Hence this method can achieve solution in a sub-linear time where network has fewer unbalanced nodes. However this method has worst case complexity of order O(m-m), where m is the number of edges. Furthermore it is shown that this theorem has also potential to make optimization an easier task in a multi-commodity flow environment. © 2012 Growing Science Ltd. All rights reserved
Flexural phonons and thermal transport in multilayer graphene and graphite

We present a theory for the lattice thermal conductivity κL of multilayer graphene (MLG) and graphite, which is based on an exact numerical solution of the Boltzmann equation for phonons. Dominant contributions to κL from out-of-plane or flexural phonons are found, which is consistent with previous findings for single-layer graphene (SLG). However, the interaction between graphene layers in MLG and graphite breaks a selection rule on phonon-phonon scattering, causing their κLs to be much lower than that of SLG. C 13 isotopes are shown to be an important scattering mechanism, accounting for an ∼15% additional drop in the κL of these systems. We demonstrate that the κL values converge to that of graphite after only about five layers, a consequence of weak interlayer coupling. These findings are qualitatively consistent with recent measurements of κL for MLG.
The Higgs boson mass in a natural minimal supersymmetric standard model with nonuniversal gaugino masses at the grand unification theory scale

We identify a parameter region where the mass of the lightest CP-even Higgs boson resides in $124.4-126.8$ GeV, and at the same time the degree of tuning a Higgsino-mass parameter (so-called $\mu$-parameter) is relaxed above 10% in the minimal supersymmetric standard model (MSSM) with soft supersymmetry breaking terms, by solving the full set of one-loop renormalization group equations numerically. It is found that certain nonuniversal values of gaugino-mass parameters at the so-called grand unification theory (GUT) scale $\sim 10^{16}$ GeV are important ingredients for the MSSM to predict, without a severe fine-tuning, the Higgs boson mass $\sim 125$ GeV indicated by recent observations at the Large Hadron Collider. We also show a typical superparticle spectrum in this parameter region.
On estimation of regression coefficients of long memory random fields observed on the arrays

It is well known that many of empirical data may exhibit long range dependence structure (see [1], [2], [3], [5], [6], [7], [10]). Thus, there is now a considerable theoretical interest in analysing different long memory models. In particular, results of [9], [12], [17], [20], [21] indicate that regression with long memory may still be very good. The interesting problems regarding estimation of parameter of long memory (fractional or Hurst parameter) are considered in papers [9], [17], [18] among the others. Recently some new models of continuous parameter long memory processes are proposed in papers [5], [6], [7]. Here are the questions about properties of the least squares estimator (LSE) of regression coefficients very important. For discrete parameter long memory time series the conditions for asymptotic normality of LSE are given in [20], [21]. Also there are some results regarding asymptotic properties of the LSE in [11], [14], [15]. In this paper we consider the continuous multidimensional version of some problems attacked in [20] and [21]. Thus, we study the asymptotic properties of the LSE in regression models with multidimensional inputs and long memory errors, not necessarily Gaussian. We don't consider the problem of estimation of fractional (Hurst's) parameter (see [2], [3], [9], [17], [6], [7]).