Miracle-dz/UniFAR-FTUs huggingface dataset:
Statistics of nodal lines and points in chaotic quantum billiards: perimeter corrections, fluctuations, curvature

For real (time-reversal symmetric) quantum billiards, the mean length L of nodal line is calculated for the nth mode (n>>1), with wavenumber k, using a Gaussian random wave model adapted locally to satisfy Dirichlet or Neumann boundary conditions. The leading term is of order k (i.e. √n), and the first (perimeter) correction, dominated by an unanticipated long-range boundary effect, is of order log k (i.e. log n), with the same sign (negative) for both boundary conditions. The leading-order state-to-state fluctuations δL are of order √log k. For the curvature κ of nodal lines, |κ| and √κ2 are of order k, but |κ|3 and higher moments diverge. For complex (e.g. Aharonov-Bohm) billiards, the mean number N of nodal points (phase singularities) in the mode has a leading term of order k2 (i.e. n), the perimeter correction (again a long-range effect) is of order klog k (i.e. √nlog n) (and positive, notwithstanding nodal depletion near the boundary) and the fluctuations δN are of order k√log k. Generalizations of the results for mixed (Robin) boundary conditions are stated.
Intervention orientations in communication research

ABSTRACT The importance of intervention in communication research has continued to expand in a variety of research traditions including applied communication, engaged scholarship, and communication activism. The growing importance of intervention requires closely examining our research practices regarding knowledge production and the role of nonacademic research partners. The present study articulates four intervention orientations based on an analysis of articles (n = 154) from 2010 to 2020, drawn from journals published by the U.S.-based Association for Education in Journalism and Mass Communication, International Communication Association, and National Communication Association. Four orientations are articulated using the dimensions of problem focus and intervention pathway: (1) translation, (2) critique, (3) design, and (4) co-creation. Implications regarding temporality and intervention, the significance of interdisciplinary research, and the sustainable social impact of interventions are highlighted.
High-speed, dual-function vertical cavity multiple quantum well modulators and photodetectors for optical interconnects

A vertical cavity multiple quantum well (MQW) modulator, which offers high contrast ratio, low insertion loss, low power consumption, low jitter and chirp, and easy two-dimensional integration with silicon electronics, is one of the essential components for dense optical interconnects. The devices we have investigated consist of quantum wells in a Fabry-Perot cavity configured as p-i-n diode. The absorptive characteristics of the MQW region can be modified through field-induced absorption change known as quantum-confined Stark effect (QCSE), which translate to the modulation in the device reflectivity. Modulators can also perform the dual function of a high-efficiency photodetector at the receiver end by using a different electronic control circuit. This has the advantage of doubling the optical I/O of a photonic layer and reducing power losses. In this paper, the high-speed performance of modulators and photodetectors will be presented. We use 26 pairs of 75-A GaAs/AlGaAs quantum wells. The modulators have a high contrast ratio of 11 dB, small driving voltage of 3.5 V, and f3dB bandwidth greater than 18 GHz. If the device is used as a high-speed photodetector, it has a quantum efficiency of 95% and f3dB bandwidth greater than 10 GHz. Results of devices of different sizes, with different bias voltages and termination resistors, are presented.
Hyperostosis Frontalis Interna in a Dry Indian Human Skull: A Case Report

Hyperostosis Frontalis Interna (HFI), a condition that has been sparsely explained till now, is a benign, asymptomatic, and irregular thickening of the endocranium of the frontal bone. It is found to be predominantly present in post-menopausal women during incidental X-ray or CT/MRI of the skull. The prevalence of HFI is documented in different populations, but in the Indian population, it is comparatively rare. Thus, we discuss a serendipitous finding of HFI in an Indian skull. This rare variation was noted in dry Indian human skulls. Gross features of the skull were noted, and it was an adult female skull. The area was decalcified, paraffin-embedded, and stained with Haematoxylin and Eosin. The skull bone was also subjected to plain X-ray/CT investigation. The X-ray skull of 50+ year female type features in anteroposterior and lateral view showed widening of the diploic spaces 8-10 mm with ill-defined hyperdense areas in the frontal region. Changes in computed tomography were noted. HFI often has nonspecific and benign symptoms. However, in severe cases, widespread clinical implications starting from headache, motor aphasia, parkinsonism, and depression can occur, and thus we all should be aware of it.
Nonlinear evolution equations

Nonlinear evolution equations arise in many fields of outside of mathematics including physics, mechanics, and material science. This book introduces some important methods for dealing with these equations and explains clearly and concisely a wide range of relevant theories and techniques. These include the semigroup method, the compactness and monotone operator methods, the monotone iterative method and invariant regions, and global existence and uniqueness theory for small initial data as well as the theory and method for the study of the asymptotic behavior of solutions and global attractors. Many of the results are published in book form for the first time. Bibliographic comments in each chapter provide the reader with references and further reading materials to enable further research and study.
1D waves in a random poroelastic medium with large fluctuations

Abstract We examine the problem of wave propagation in a random poroelastic medium. The porous medium is modelled as a Biot poroelastic solid whose constitutive parameters fluctuate substantially over finite distances. Our main results are asymptotic analytical expressions for the mean velocity-stress wave; this solution incorporates two distinct length scales. The effect of the fluctuations appears on the regular depth coordinate while the parameters of the effective medium arise on a shorter scale of distance. Thus the method that we apply, the theory of averaging, allows us to give a rigorous derivation of the effective medium parameters. It also provides the correction terms which are caused by the fluctuations in the random medium; we find that the relative effect of the latter increases in proportion to ω1/2 where ω denotes the wave frequency. We also show that the fluctuations introduce significant attenuation of the fast Biot compressional wave and dispersion of the slow Biot wave. These results a.
Correlation decoding of the (24, 12) Golay code using neural networks

The (24, 12) extended Golay code contains eight disjoint subcodes. Each subcode can be constructed from 24 (real) orthogonal base vectors. It further contains 64 sub-subcodes that are equivalent to a three-dimensional universe code. This structure enables us to use partial correlation between the received vector and the base vectors to perform ideal correlation decoding. The correlation decoder can be implemented with a 64-flop and an 8-flop Hopfield neural network plus some housekeeping logic.
Head-related transfer function interpolation through multivariate polynomial fitting of principal component weights

Head-related transfer function (HRTF) interpolation plays an important role for implementation of 3D sound system because it can not only reduce the number of measurements for HRTFs, but also reduce the data of HRTFs for seamless binaural synthesis. This paper addresses the problem of accurately realizing the interpolation of HRTF for synthesis of virtual auditory space, and proposes a HRTF interpolation method based on principal component analysis. Firstly, the HRTF is decomposed into principal components and corresponding principal component weights, where principal components are direction-independent and principal component weights are direction- dependent; then the directional variation of the principal component weight is multivariate polynomial fitted with a bivariate function of two spatial angulus (azimuth and elevation). Moreover, a sphere- partitioning optimization scheme is employed to improve the approximation precision. Experiment results demonstrate that HRTFs in the entire sphere surface can be interpolated by the proposed method with small distortion, and the proposed method performs better than conventional methods. Therefore the proposed method gives a promising way for HRTF interpolation.
Strong resonance in two‐dimensional non‐Boussinesq convection

Two‐dimensional convection is described and analyzed in the case of strong 2:1 resonance. The density variation due to the temperature to linear order and the viscous heating as perturbations to the usual Boussinesq approximation are introduced. In addition the temperature dependence of the viscosity is taken into account. In this special setting one is able to quantify the influence of these effects on the dynamics. They break the symmetry with respect to reflections at the horizontal midplane that is artificially induced when adopting the Boussinesq approximation, and give rise to an O(2) symmetric bifurcation problem. Time‐dependent solutions appear and become stable when the Prandtl number lies between two critical values, between zero and one. In this case there also exists a structurally stable heteroclinic orbit very close to the onset of motion in a small amplitude limit. A similar orbit exists outside this limit if Pr is sufficiently small and the viscosity ratio is relatively large. This behavior is in contrast to previous results obtained by adopting the Boussinesq approximation where only stationary convection patterns persist. Finally a brief survey over real fluids is given and the resulting dynamics is described.
Linear Stability Analysis of Runge–Kutta-Based Partial Time-Splitting Schemes for the Euler Equations

Abstract For atmospheric simulation models with resolutions from about 10 km to the subkilometer cloud-resolving scale, the complete nonhydrostatic compressible Euler equations are often used. An important integration technique for them is the time-splitting (or split explicit) method. This article presents a comprehensive numerical stability analysis of Runge–Kutta (RK)-based partial time-splitting schemes. To this purpose a linearized two-dimensional (2D) compressible Euler system containing advection (as the slow process), sound, and gravity wave terms (as fast processes) is considered. These processes are the most important ones in limiting stability. First, the detailed stability properties are discussed with regard to several off-centering weights for each fast process described by horizontally explicit, vertically implicit schemes. Then the stability properties of the temporally and spatially discretized three-stage RK scheme for the complete 2D Euler equations and their stabilization (e.g., by div.
Computational Optimization of a Groove-Enhanced Minichannel

To meet the challenging thermal requirements of modern power electronics, surface enhancements are being considered to improve the performance of single-phase microchannels. A simple modification of a surface dimple—a two-dimensional groove—is considered due to its significant potential enhancement yet simple manufacture. A comprehensive series of simulations were performed to determine the optimal geometry and Reynolds numbers for thermal performance, which indicated that moderately deep features could result in nearly 75% greater average convective heat transfer coefficient with approximately 35% greater pressure penalty at turbulent conditions. This geometry promoted freestream separation at the leading edge, which resulted in downstream impingement and boundary layer development, producing an overall thermal benefit. This potential performance was demonstrated experimentally using a groove-enhanced minichannel design in a typical heat-sink application. Infrared thermography showed that deep grooves could indeed enhance the overall heat transfer coefficient of this module by the order of 20%, although shallower shapes had less impact.
Second Derivative Sample Path Estimators for the GI/G/m Queue

Applying the technique of smoothed perturbation analysis SPA to the GI/G/m queue with first-come, first-served FCFS queue discipline, we derive sample path estimators for the second derivative of mean steady-state system time with respect to a parameter of the service time distribution. Such estimators provide a possible means for speeding up the convergence of gradient-based stochastic optimization algorithms. The derivation of the estimators sheds some new light on the complications encountered in applying the technique of SPA. The most general cases require the simulation of additional sample subpaths; however, an approximation procedure is also introduced which eliminates the need for additional simulation. Simulation results indicate that the approximation procedure is reasonably accurate. When the service times are exponential or deterministic, the estimator simplifies and the approximation procedure becomes exact. For the M/M/2 queue, the estimator is proved to be strongly consistent.
Genetic evidence that high BMI in childhood has a protective effect on intermediate diabetes traits, including measures of insulin sensitivity and secretion

Determining how high body-mass index (BMI) at different time points influences the risk of developing type two diabetes (T2D), and affects insulin secretion and insulin sensitivity, is critical. By estimating childhood BMI in 441,761 individuals in the UK Biobank, we identified which genetic variants had larger effects on adulthood BMI than on childhood BMI, and vice-versa. All genome-wide significant genetic variants were then used to separate the independent genetic effects of high childhood BMI from high adulthood BMI on the risk of T2D and insulin related phenotypes using Mendelian randomisation and studies of T2D, and oral and intravenous measures of insulin secretion and sensitivity. We found that a 1.s. d. (= 1.97kg/m2) higher childhood BMI, corrected for the independent genetic liability to adulthood BMI, was associated with a protective effect for seven measures of insulin sensitivity and secretion, including an increased insulin sensitivity index ({beta} = 0.15 [0.067, 0.225], p = 2.79E-4), and reduced fasting glucose ({beta} = -0.053 [-0.089, -0.017], p = 4.31E-3). There was however little to no evidence of a direct protective effect on T2D (OR = 0.94 [0.85 - 1.04], p = 0.228), independently of genetic liability to adulthood BMI. Our results thus cumulatively provide evidence of the protective effect of higher childhood BMI on insulin secretion and sensitivity, which are crucial intermediate diabetes traits. However, we stress that our results should not currently lead to any change in public health or clinical practice, given the uncertainty in biological pathway of these effects, and the limitations of this type of study.
A machine learning approach in the estimation of a radioactive source position using a coded aperture device

Coded Aperture γ-cameras have been used for more than three decades for imaging radioactive source distributions encountered in astrophysics, in decommissioning of nuclear facilities, and in nuclear medicine. These devices enable the identification of the coordinates of γ-emitters located within their Field of View (FOV) with the use of the coded-aperture shadow projected on pixelated detectors. In this work we have developed machine learning algorithms based on Gradient Boosted Decision Trees (BDTG) and Deep Neural Networks (DNN). The algorithms have been trained using 21000 shadowgrams created with simulation. A custom fast simulation tool was used to produce the shadowgrams due to sources placed randomly at different positions within the FOV at distances from 20 cm up to 20 m from the detector plane. The performance of the algorithms has been evaluated with the aid of a different independent simulation sample of shadowgrams and verified with real data.
A Possible Chemical Clock in High-mass Star-forming Regions: N(HC3N)/N(N2H+)?

We conducted observations of multiple HC3N (J = 10−9, 12−11, and 16−15) lines and the N2H+ (J = 1−0) line toward a large sample of 61 ultracompact (UC) H ii regions, through the Institut de Radioastronomie Millmétrique 30 m and the Arizona Radio Observatory 12 m telescopes. The N2H+ J = 1−0 line is detected in 60 sources and HC3N is detected in 59 sources, including 40 sources with three lines, 9 sources with two lines, and 10 sources with one line. Using the rotational diagram, the rotational temperature and column density of HC3N were estimated toward sources with at least two HC3N lines. For 10 sources with only one HC3N line, their parameters were estimated, taking one average value of T rot. For N2H+, we estimated the optical depth of the N2H+ J = 1−0 line, based on the line intensity ratio of its hyperfine structure lines. Then the excitation temperature and column density were calculated. When combining our results in UC H ii regions and previous observation results on high-mass starless cores, the N(HC3N)/N(N2H+) ratio clearly increases from the region stage. This means that the abundance ratio changes with the evolution of high-mass star-forming regions (HMSFRs). Moreover, positive correlations between the ratio and other evolutionary indicators (dust temperature, bolometric luminosity, and luminosity-to-mass ratio) are found. Thus we propose the ratio of N(HC3N)/N(N2H+) as a reliable chemical clock of HMSFRs.
Radio and γ-Ray Variability in Blazar S5 0716+714: A Year-like Quasi-periodic Oscillation in the Radio Light Curve

The nearly 33 yr long-term radio light curve obtained with the Metsähovi Radio Observatory 14 m telescope at 37 GHz and the recent 12.7 yr γ-ray light curve of the blazar S5 0716+714 at 0.1–300 GeV from the Fermi Large Area Telescope (Fermi-LAT) were analyzed by using the Lomb–Scargle periodogram and the weighted wavelet Z-transform techniques. In the radio light curve, we discovered a possible quasi-periodic oscillation (QPO) signal of about 352 ± 23 days at a confidence level of ∼3σ. We recalculated the periodicity and its significance in a chosen time range that has higher variability and denser sampling, and then found that the significance had increased to a confidence level of 99.996% (∼4.1σ). This QPO component was further confirmed by fitting a linear autoregressive integrated moving average model to the selected radio light curve. A possible QPO of 960 ± 80 days at a 99.35% level (∼2.7σ) was found in the γ-ray light curve, which generally agrees with the earlier QPO claims of S5 0716+714. This paper discusses possible mechanisms for this potential year-like QPO. One possibility is a pure geometrical scenario with blobs moving helically inside the jet. Another is a supermassive binary black hole involving a gravitational wave-driven regime. In the latter scenario, we derived a milliparsec separation in the binary system that undergoes coalescence within a century due to the emission of low-frequency gravitational waves.
Laser gated viewing: An enabler for automatic target recognition?

For many decades attempts to accomplish Automatic Target Recognition have been made using both visual and FLIR camera systems. A recurring problem in these approaches is the segmentation problem, which is the separation between the target and its background. This paper describes an approach to Automatic Target Recognition using a laser gated viewing system. Here laser-flash illumination is used in combination with a gating viewer such that only a small part in the distance domain is seen in a single image. In our approach, using an Intevac LIVAR 4000 imaging system, we combined several images with different gate settings to construct a 3D data cube. This paper describes the preprocessing and filtering steps taken to obtain a range image for which pixel values represent the distance between camera and objects in the illuminated scene. Depth segmentation is performed using the global histogram of this range image. After this depth segmentation very good 2D object segmentations can be obtained which can be used to classify persons and vehicles. An outlook will be given towards operational application of this procedure.
Laser Short-Pulse Heating of Silver-Chromium Assembly: Improved Formulation of Electron Kinetic Theory Approach

Laser short-pulse heating of a two-layer assembly consisting of silver (40 nm thick) at the top, and chromium (800 nm) at the bottom, is considered, and the temperature field in the electron as well as electron subsystems is predicted. An improved formulation of the electron kinetic theory approach accommodating the ballistic contribution of electrons to energy transport is used when modeling the heating. In addition, electron and lattice temperatures in silver and chromium as a single substrate are predicted for comparison. It is found that the chromium layer situated below the silver layer modifies significantly the temperature rise in the silver layer. This situation is also observed for the Seebeck coefficient.
Solar Coronal Heating Fueled by Random Bursts of Fine-scale Magnetic Reconnection in Turbulent Plasma Regions

Coronal heating is a longstanding issue in solar physics as well as plasma physics in general. In recent years, significant resolution improvements of satellite observations have contributed to a deeper understanding of small-scale physics, e.g., magnetic reconnection processes on fine scales inside the turbulent geo-magnetosheath. Coronal plasmas feature turbulent complexity of flows and magnetic fields with similar fine scales, and thus electron magnetic reconnection is very likely to be excited in the coronal region working as one of the ways to heat the solar corona, which offers a possible new mechanism for the nanoflare model proposed by Parker. We in this paper simulate and analyze the magnetic reconnection processes on a fine scale of the electron skin depth, with a particle-in-cell treatment, and estimate its contribution to coronal heating. The result shows that the electron magnetic reconnection can provide substantial heating efficiency for heating the corona to its observed temperature, once the reconnection events are reasonably spread.
3D Fourth-Order Staggered-Grid Finite-Difference Schemes: Stability and Grid Dispersion

We investigated stability and grid dispersion in the 3D fourth-order in space, second-order in time, displacement-stress staggered-grid finite-difference scheme. Though only displacement-stress scheme is explicitly treated, all results also apply to the velocity-stress and displacement-velocity-stress finite-difference schemes. We derived independent stability conditions for the P and S waves by exact separation of equations for the two types of waves. Since the S -wave group velocity can differ from the actual velocity as much as 5% for the sampling ratio 1/5 (that is usually used in modeling), we recommend to sample a minimum S wavelength by six grid spacings. Grid dispersion is strongest for a wave propagating in the direction of a coordinate axis and weakest for a wave propagating along a body diagonal. Grid dispersion in the fourth-order scheme for the sampling ratios s = 1/5 and s = 1/6 is smaller than grid dispersion in the second-order scheme for s = 1/10 and s = 1/12, respectively.