Miracle-dz/UniFAR-FTUs huggingface dataset:
Simulation of relativistic shocks and associated radiation from turbulent magnetic fields

Abstract Recent PIC simulations of relativistic electron-positron (electron-ion) jets injected into a stationary medium show that particle acceleration occurs in the shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and for particle acceleration. These magnetic fields contribute to the electron's transverse deflection behind the shock. The “jitter” radiation from deflected electrons in turbulent magnetic fields has different properties from synchrotron radiation calculated in a uniform magnetic field. This jitter radiation may be important for understanding the complex time evolution and/or spectral structure of gamma-ray bursts, relativistic jets in general, and supernova remnants. In order to calculate radiation from first principles and go beyond the standard synchrotron model, we have used PIC simulations. We will present detailed spectra for conditions relevant to various astrophysical sites of collisionless shock formation. In particular we will discuss application to GRBs and SNRs.
An Efficient Low Complexity Region-of-Interest Detection for Video Coding in Wireless Visual Surveillance

Moving object detection (MOD) has become a popular topic in video analysis due to its use in several applications, including video coding in wireless surveillance. However, implementing MOD in constrained sensors is challenging due to their high complexity and energy consumption. Therefore, there is a great need to address the trade-off between the accuracy and the energy efficiency of MOD approaches for video coding in constrained systems. In this work, an energy-efficient region-of-interest (ROI) detection algorithm as a pre-encoder for wireless visual surveillance (WVS) is proposed. The algorithm ensures a trade-off between detection accuracy and computational complexity. To this end, we propose constructing an activity map by measuring each block activity between successive frames. The map scores are processed using a combination of a fast Gaussian smoother and a rank-order filter to improve accuracy. Only the blocks in motion are coded and counted for transmission. The accuracy of our approach has been evaluated on a large dataset using key performance metrics. It has been found that our algorithm outperforms other state-of-the-art techniques in terms of true positive rate (TPR), with 80.84% on sensitivity metric, while exhibiting a well-balanced accuracy for all categories. A careful examination of the computational complexity confirms the low overhead. The energy and bitrate savings could achieve nearly 90% and 98%, respectively.
Modeling and simulation of coverage and film properties in deposition process on large-scale pattern using statistical ensemble method

This study modeled deposition processes using statistical ensemble and feature-scale voxel methods to predict the coverage and film properties on a large-scale pattern for the first time. Certain new concepts, such as the use of probabilities to express physical and chemical phenomena occurring on the surface, interaction among voxels, and super particles for fast calculations, were introduced. Further, the model was used to analyze the experimental characteristic variation between the morphology and film density of SiN in low-temperature plasma-enhanced chemical vapor deposition using a SiH4/NH3/N2 gas mixture with different SiH4 flow rates, which has not been found in SiO2 films. The simulation results demonstrated the effect of the precursor mass in the gas phase on surface migration and morphology formation. In addition, a short residence time was required to prevent the generation of large and heavy precursors to realize good SiN coverage and film properties at a low temperature.
Mechanisms of Immune-Related Long Non-Coding RNAs in Spleens of Mice Vaccinated with 23-Valent Pneumococcal Polysaccharide Vaccine (PPV23)

The 23-valent pneumococcal vaccine (PPV23) is a classical common vaccine used to prevent pneumococcal disease. In past decades, it was thought that vaccination with this vaccine induces humoral immunity, thereby reducing the disease associated with infection with 23 common serotypes of Streptococcus pneumoniae (Sp). However, for this polysaccharide vaccine, the mechanism of immune response at the transcriptional level has not been fully studied. To identify the lncRNAs (long noncoding RNAs) and mRNAs in spleens related to immunity after PPV23 vaccination in mice, high-throughput RNA sequencing of spleens between a PPV23 treatment group and a control group were performed and evaluated in this study. The RNA-seq results identified a total of 41,321 mRNAs and 34,375 lncRNAs, including 55 significantly differentially expressed (DE) mRNAs and 389 DE lncRNAs (p < 0.05) between the two groups. GO and KEGG annotation analysis indicated that the target genes of DE lncRNAs and DE mRNAs were related to T-cell costimulation, positive regulation of alpha–beta T-cell differentiation, the CD86 biosynthetic process, and the PI3K-Akt signaling pathway, indicating that the polysaccharide component antigens of PPV23 might activate a cellular immune response during the PPV23 immunization process. Moreover, we found that Trim35 (tripartite motif containing 35), a target gene of lncRNA MSTRG.9127, was involved in regulating immunity. Our study provides a catalog of lncRNAs and mRNAs associated with immune cells’ proliferation and differentiation, and they deserve further study to deepen the understanding of the biological processes in the regulation of PPV23 during humoral immunity and cellular immunity.
Comparison of hyperspectral endmember extraction algorithms

Abstract In hyperspectral imagery, endmember extraction is the process of finding a pure spectrum set within the materials present in a hyperspectral scene. However, various endmember extraction algorithms (EEAs) can yield different endmember spectrum sets. This research presents a comparison of four EEAs: pixel purity index, automatic target generation process (ATGP), N-finder (N-FINDR), and simplex identification via split augmented Lagrangian. To perform the comparison, a ground reference geological map is first coregistered with the hyperspectral scene. Then, 12 geological ground truth spectra are chosen. The four EEAs are then used to extract endmember spectra from the scene. Next, the extracted endmember spectra are applied to generate abundance maps using fully constrained least squares. The largest spectrum magnitude in the abundance map is considered the endmember. Finally, the spectral angle mapper and root-mean-square error between the extracted endmember spectrum and the chosen geological spectral spectra are computed, using the angle and minimum error to evaluate similarities. The results of this EEA comparison show that only the ATGP algorithm could consistently identify endmembers with the least computation time. Additionally, the N-FINDR algorithm is able to extract the most endmembers with the closest endmember similarity measures, although this required the highest computation time.
Prediction of wind speed for the estimation of wind turbine power output from site climatological data using artificial neural network

In this paper, the wind speeds of Noupoort in the Western Cape region of South Africa are forecasted from the site climatological data using feed forward artificial neural network (ANN) with the back propagation training method. Different architectural designs are tested with different combinations of climatological data to obtain the most suitable ANN for predicting the wind speed of the site. The predicted wind speeds are compared with the actual measured wind speeds and the results are evaluated using mean absolute error (MAE), mean absolute percentage error (MAPE), root mean square error (RMSE) and correlation coefficient (R). Some of the key results show that combination of temperature, wind direction and time of the day (TEM + WD + T) could effectively predict wind speed of Noupoort. The forecasted wind speed shows a strong agreement with the measured wind speed with R, RMSE, MAPE and MAE of 0.96, 0.56, 6.64% and 0.44, respectively.
Laplace Expansions in Markov chain Monte Carlo Algorithms

Complex hierarchical models lead to a complicated likelihood and then, in a Bayesian analysis, to complicated posterior distributions. To obtain Bayes estimates such as the posterior mean or Bayesian confidence regions, it is therefore necessary to simulate the posterior distribution using a method such as an MCMC algorithm. These algorithms often get slower as the number of observations increases, especially when the latent variables are considered. To improve the convergence of the algorithm, we propose to decrease the number of parameters to simulate at each iteration by using a Laplace approximation on the nuisance parameters. We provide a theoretical study of the impact that such an approximation has on the target posterior distribution. We prove that the distance between the true target distribution and the approximation becomes of order O(N−a) with a ∈ (0, 1), a close to 1, as the number of observations N increases. A simulation study illustrates the theoretical results. The approximated MCMC algorithm behaves extremely well on an example which is driven by a study on HIV patients.
A bootstrap procedure in linear regression with nonstationary errors

In the context of linear regression with dependent and nonstationary errors, the classical moving‐block bootstrap (MBB) fails to capture the nonstationarity of the errors. A new bootstrap procedure called the blocking external bootstrap (BEB) is proposed to overcome the problem. The consistency of the BEB in estimating the variance of the least‐squares estimator is studied in the case of α‐mixing and nonstationary sequence of errors. It is shown that the BEB only achieves partial correction if the block size is fixed. Complete consistency is achieved by the BEB when the block size is allowed to go to infinity. We also study the first‐order consistency of the least squares estimator based on the BEB. A simulation study is carried out to assess the performance of the BEB versus the MBB in estimating the variance of the least‐squares estimator. Finally, some open problems are discussed.
On proper Fredholm submanifolds in a Hilbert space arising from submanifolds in a symmetric space

By Naoyuki KOIKE (Received January 29, 2001) (from Tokyo Journal of Mathematics) Abstract. For a given symmetric space of compact type, it is known that a certain Riemannian submersion of a Hilbert space onto the symmetric space is nat urally defined. In this paper, we describe the principal curvatures and the principal distributions of the inverse image (which becomes a proper Fredholm submanifold) of a curvature adapted submanifold in the symmetric space under this Riemannian submer sion. The curvature adapted submanifold is minimal if and only if the inverse image is formally minimal in certain sense.
Voxel-based recovery and trajectory separable error rectification for multi-view 3D pose reconstruction of jump analysis in figure skating

Successful jumps in figure skating with critical parameters such as proper jump height, spin speed, and the number of jump rotations, which are valuable for analysis in athlete training. Driven by recent computer vision applications, reconstructing 3D poses of the athlete in figure skating to extract the significant variables has become increasingly important. However, a large number of conventional works have obtained 3D poses from corresponding 2D information directly, which ignores the uniqueness of figure skating, such as self-occlusion, abnormal poses, etc. This paper proposes a multi-view voxel based system for calibration and error correction to reconstruct the 3D jumping poses of figure skaters in the presence of 2D heatmaps. The proposed method consists of two key components: Voxels based recovery method of high probability area in 2D heatmap; Plain 2D smoothness and motion trajectory and relative joint positions separable 3D smoothness based rectification method. This work is proven to be applicable to 3D pose dynamics in figure skating jumping motion. Mean Per Joint Position Error (MPJPE) is: 34.58mm in the pre-jump stage, 16.51mm in the jumping stage, 15.73mm in the post-jump stage, and 16.93mm in the whole jump stage, which is 36% improvement compared with the conventional work.
Coronal magnetic field modeling using stereoscopy constraints

Aims. Nonlinear force-free field (NLFFF) extrapolation has been used extensively in the past to extrapolate solar surface magnetograms to stationary coronal field models. In theoretical tests with known boundary conditions, the nonlinear boundary value problem can be solved reliably. However, if the magnetogram is measured with errors, the extrapolation often yields field lines that disagree with the shapes of simultaneously observed and stereoscopically reconstructed coronal loops. We here propose an extension to an NLFFF extrapolation scheme that remedies this deficiency in that it incorporates the loop information in the extrapolation procedure. Methods. We extended the variational formulation of the NLFFF optimization code by an additional term that monitors and minimizes the di erence of the local magnetic field direction and the orientation of 3D plasma loops. We tested the performance of the new code with a previously reported semi-analytical force-free solution. Results. We demonstrate that there is a range of force-free and divergence-free solutions that comply with the boundary measurements within some error bound. With our new approach we can obtain the solution out of this set the coronal fields which is well aligned with given loops. Conclusions. We conclude that the shape of coronal loops reconstructed by stereoscopy may lead to an important stabilization of coronal NLFFF field solutions when, as is typically the case, magnetic surface measurements with limited precision do not allow determining the solution solely from photospheric field measurements.
Ship-to-ship maritime wireless channel modeling under various sea state conditions based on REL model

The propagation of electromagnetic waves on land and sea is significantly different. Although the Los scenario is significant in marine wireless communication, the marine wireless channel exists an obvious two-ray phenomenon due to the strong reflection path reflected through the sea surface. By modeling the measured data of marine wireless channels, this paper calculates the radio propagation characteristics of the Pearl River estuary. In addition, the wave fluctuations and high humidity environment will also impact the properties of the marine wireless channel. Therefore, sea surface morphology models under multiple wind speeds are built. To estimate the path loss in the same area under different conditions, the Monte Carlo method is employed to quantify the results. The simulation results show that the electric wave propagation gradually degenerated from the round earth loss (REL) model to the free space model with increasing wind speed. Moreover, the distribution of the shadow fading varies with distance. The findings provide references for the network planning of marine communication.
ICT USE AND ATTITUDES AMONG SECONDARY EDUCATION TEACHERS IN ROMANIA

Secondary education in Romania has moved quickly over the last decade from a practical inexistence of ICT in schools to a decent level of endowment and access (although with enough room for improvement). Has the improved ICT access raised the actual level of ICT use in education? What makes some teachers use ICT more than others? This paper investigates the determinants of ICT use (and intention of use) among secondary education teachers (ISCED 2-3) in Romania. It makes use of data from one of the first representative surveys of its kind of secondary education teachers in Romania. Data (unused in prior academic research) about 1053 teachers from 150 schools was collected, under the supervision of this paper's authors, within a nation-wide, EU funded, e-learning training project. The paper reviews and applies the main theoretical frameworks used broadly by international research literature on technology adoption in education and other areas,primarily the Technology Acceptance Model (Fred D. Davis) and Innovation Diffusion Theory (Everett M. Rogers). It explores the role of variables such as: perceived usefulness (of ICT), ease of use, personal innovativeness, technology compatibility, visibility, etc. To obtain these results multivariate techniques such as Ordinary Least Squares and Structural Equation Modeling are employed. We expect our study to make a double contribution. From an empirical point of view it produces evidence from a country that remains largely unstudied by the research literature on technology adoption in education, attempting to place the wider theoretical models in Romanian context. From a theoretical and methodological perspective, the main theories in the field are not just tested alternatively (by turn) but put to the test simultaneously to obtain a pooled and hopefully improved model.
Axial polarizers based on dichroic liquid crystals

Polarizers capable of producing linearly polarized beams with axial (radial and azimuthal) symmetry have been fabricated with the aid of a dichroic liquid crystal. Photoalignment was achieved using a printing technique to reduce the UV exposure time required for production of axially aligning substrates from 1 h, typical for direct writing techniques, to 10 min. The polarizing features of axial polarizers and their pairs are characterized and their differences outlined. We demonstrate that the transmission switching contrast of an axial polarizer/analyzer pair, comprised of an electrically controlled liquid crystal cell, is comparable to conventional systems with linear polarizers. The opportunities for using axial polarizers for polarization imaging, sensor protection, and nonlinear optics are discussed. Particularly, we show that the technology could reduce the fluence of a laser beam on an optical sensor without affecting imaging.
Discovery of unknown new ponds occupied by the endangered giant water bug Kirkaldyia deyrolli (Hemiptera: Heteroptera: Belostomatidae) by combining environmental DNA and capture surveys

Basic ecological information (e.g. habitat or distribution) is indispensable for conserving endangered species. The giant water bug Kirkaldyia deyrolli is an aquatic insect in the large stink bug family (Belostomatidae). It inhabits ponds and is a critically endangered species. In this study, we developed a species‐specific primer–probe set (the cytochrome c oxidase I region in mitochondrial DNA) that was used in real‐time polymerase chain reaction (PCR) assays to detect K. deyrolli environmental DNA (eDNA). Next, using eDNA analysis, we investigated the presence of K. deyrolli in 89 study ponds (including one pond that had already been identified as the habitat of this species) in Shimane Prefecture, Japan. The eDNA of K. deyrolli was detected in 11 of these 89 ponds. Furthermore, when the traditional method of direct capture survey was carried out in four of the 10 ponds where K. deyrolli eDNA had been detected and no prior occupancy information for this species was available, the capture of one K. deyrolli (female) was successful in only one pond. This study showed that combining eDNA analysis and direct capture methods can lead to discovering previously unknown habitats essential for conserving an endangered species.
Development of Iodine Cells for the Subaru HDS and the Okayama HIDES : II. New Software for Precise Radial Velocity Measurements

We have developed a computer code for precise measurements of stellar radial velocity variations with iodine (I2) cells attached to the High Dispersion Spectrograph (HDS) on Subaru Telescope and the HIgh Dispersion Echelle Spectrograph (HIDES) on Okayama 188cm reflector. Our modeling technique for I2 data is similar to those described by Butler et al. (1996, AAA 65.036.447) and Valenti et al. (1995, AAA 64.036.209) concerning the point that the stellar spectrum taken through the I2 cell (star + I2 spectrum) is modeled as the product of high-resolution stellar and I2 template spectra convolved with the modeled instrumental profile (IP) of the spectrograph. In order to generate a template stellar spectrum, we have devised a new method to extract an intrinsic stellar spectrum from observed star + I2 spectra. This enables us to obtain a well-established template stellar spectrum even in cases when the IP and the wavelength scale are apt to vary with time and the observational conditions, and the existing method which reconstructs the IP from a B-star + I2 spectrum (Butler et al. 1996; Endl et al. 2000, A&A, 362, 585) fails. We here report on the results of our Doppler measurements of three solar-type stars, 16 Cyg B, τ Cet, and υ And, based on data collected with HDS and HIDES for about one year. These results show that we have achieved a precision of about 5–6ms −1 over a time span of one year with our current analysis package with both spectrographs.
Serum Metabolites Associated with Muscle Hypertrophy after 8 Weeks of High- and Low-Load Resistance Training

The mechanisms responsible for the similar muscle growth attained with high- and low-load resistance training (RT) have not yet been fully elucidated. One mechanism is related to the mechanical stimulus and the level of motor unit recruitment; another mechanism is related to the metabolic response. We investigated the electromyographic signal amplitude (sEMG) and the general metabolic response to high-load RT (HL) and low-load resistance training (LL). We measured muscle thickness by ultrasound, sEMG amplitude by electromyography, and analysis of metabolites expressed through metabolomics. No differences were observed between the HL and LL groups for metabolic response and muscle thickness. A greater amplitude of sEMG was observed in the HL group. In addition, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle in the HL group and levels of the metabolites carnitine, creatine, 3-hydroxyisovalerate, phenylalanine, asparagine, creatine phosphate, and methionine. In the LL group, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle and levels of the metabolites acetoacetate, creatine phosphate, and oxypurinol. These correlations seem to be related to the characteristics of activated muscle fibers, the metabolic demand of the training protocols used, and the process of protein synthesis.
Zeeman-Doppler imaging of II Peg

Abstract We present Zeeman-Doppler images of the active K2 star II Peg for the years 2004 and 2007. The surface magnetic field was reconstructed with our new ZDI code iMap which provides a full polarized radiative transfer driven inversion to simultaneously reconstruct the surface temperature and magnetic vector field distribution. II Peg shows a remarkable large scale magnetic field structure for both years. The magnetic field is predominantly located at high latitudes and is arranged in active longitudes. A dramatic evolution in the magnetic field structure is visible for the two years, where a dominant and largely unipolar field in 2004 has changed into two distinct and large scale bipolar structures in 2007.