Miracle-dz/UniFAR-FTUs huggingface dataset:
Studying the Solar system with the International Pulsar Timing Array

Pulsar-timing analyses are sensitive to errors in the Solar-system ephemerides (SSEs) that timing models utilize to estimate the location of the Solar-system barycentre, the quasi-inertial reference frame to which all recorded pulse times-of-arrival are referred. Any error in the SSE will affect all pulsars, therefore pulsar timing arrays (PTAs) are a suitable tool to search for such errors and impose independent constraints on relevant physical parameters. We employ the first data release of the International Pulsar Timing Array to constrain the masses of the planet–moons systems and to search for possible unmodelled objects (UMOs) in the Solar system. We employ 10 SSEs from two independent research groups, derive and compare mass constraints of planetary systems, and derive the first PTA mass constraints on asteroid-belt objects. Constraints on planetary-system masses have been improved by factors of up to 20 from the previous relevant study using the same assumptions, with the mass of the Jovian system measured at 9.5479189(3) × 10^(−4) M⊙. The mass of the dwarf planet Ceres is measured at 4.7(4) × 10^(−10) M⊙. We also present the first sensitivity curves using real data that place generic limits on the masses of UMOs, which can also be used as upper limits on the mass of putative exotic objects. For example, upper limits on dark-matter clumps are comparable to published limits using independent methods. While the constraints on planetary masses derived with all employed SSEs are consistent, we note and discuss differences in the associated timing residuals and UMO sensitivity curves.
Universal bound on the strong coupling scale of a gravitationally coupled massive spin-2 particle

We find a model-independent upper bound on the strong coupling scale for a massive spin-2 particle coupled to Einstein gravity. Our approach is to directly construct tree-level scattering amplitudes for these degrees of freedom and use them to find the maximum scale of perturbative unitarity violation. The highest scale is $\Lambda_3=\left(m^2M_P\right)^{1/3}$, which is saturated by ghost-free bigravity. The strong coupling scale can be further raised to $M_P$ if the kinetic term for one particle has the wrong sign, which uniquely gives the amplitudes of quadratic curvature gravity. We also discuss the generalization to massive higher-spin particles coupled to gravity.
Higher Order Moments of the Matter Distribution in Scale-free Cosmological Simulations with Large Dynamic Range

We calculate reduced moments (xi bar)(sub q) of the matter density fluctuations, up to order q = 5, from counts in cells produced by particle-mesh numerical simulations with scale-free Gaussian initial conditions. We use power-law spectra P(k) proportional to k(exp n) with indices n = -3, -2, -1, 0, 1. Due to the supposed absence of characteristic times or scales in our models, all quantities are expected to depend on a single scaling variable. For each model, the moments at all times can be expressed in terms of the variance (xi bar)(sub 2), alone. We look for agreement with the hierarchical scaling ansatz, according to which ((xi bar)(sub q)) proportional to ((xi bar)(sub 2))(exp (q - 1)). For n less than or equal to -2 models, we find strong deviations from the hierarchy, which are mostly due to the presence of boundary problems in the simulations. A small, residual signal of deviation from the hierarchical scaling is however also found in n greater than or equal to -1 models. The wide range of spectra considered and the large dynamic range, with careful checks of scaling and shot-noise effects, allows us to reliably detect evolution away from the perturbation theory result.
Influence of Heat Accumulation on Morphology Debris Deposition and Wetting of LIPSS on Steel upon High Repetition Rate Femtosecond Pulses Irradiation

The fabrication of laser-induced periodic surface structures (LIPSS) over extended areas at high processing speeds requires the use of high repetition rate femtosecond lasers. It is known that industrially relevant materials such as steel experience heat accumulation when irradiated at repetition rates above some hundreds of kHz, and significant debris redeposition can take place. However, there are few studies on how the laser repetition rate influences both the debris deposition and the final LIPSS morphology. In this work, we present a study of fs laser-induced fabrication of low spatial frequency LIPSS (LSFL), with pulse repetition rates ranging from 10 kHz to 2 MHz on commercially available steel. The morphology of the laser-structured areas as well as the redeposited debris was characterized by scanning electron microscopy (SEM) and µ-Raman spectroscopy. To identify repetition rate ranges where heat accumulation is present during the irradiations, we developed a simple heat accumulation model that solves the heat equation in 1 dimension implementing a Forward differencing in Time and Central differencing in Space (FTCS) scheme. Contact angle measurements with water demonstrated the influence of heat accumulation and debris on the functional wetting behavior. The findings are directly relevant for the processing of metals using high repetition rate femtosecond lasers, enabling the identification of optimum conditions in terms of desired morphology, functionality, and throughput.
Resonances in the two-center Coulomb systems

We investigate the existence of resonances for two-center Coulomb systems with arbitrary charges in two dimensions, defining them in terms of generalized complex eigenvalues of a non-selfadjoint deformation of the two-center Schrodinger operator. We construct the resolvent kernels of the operators and prove that they can be extended analytically to the second Riemann sheet. The resonances are then analyzed by means of perturbation theory and numerical methods.
An infrared-visible image fusion scheme based on NSCT and compressed sensing

Image fusion, as a research hot point nowadays in the field of infrared computer vision, has been developed utilizing different varieties of methods. Traditional image fusion algorithms are inclined to bring problems, such as data storage shortage and computational complexity increase, etc. Compressed sensing (CS) uses sparse sampling without knowing the priori knowledge and greatly reconstructs the image, which reduces the cost and complexity of image processing. In this paper, an advanced compressed sensing image fusion algorithm based on non-subsampled contourlet transform (NSCT) is proposed. NSCT provides better sparsity than the wavelet transform in image representation. Throughout the NSCT decomposition, the low-frequency and high-frequency coefficients can be obtained respectively. For the fusion processing of low-frequency coefficients of infrared and visible images , the adaptive regional energy weighting rule is utilized. Thus only the high-frequency coefficients are specially measured. Here we use sparse representation and random projection to obtain the required values of high-frequency coefficients, afterwards, the coefficients of each image block can be fused via the absolute maximum selection rule and/or the regional standard deviation rule. In the reconstruction of the compressive sampling results, a gradient-based iterative algorithm and the total variation (TV) method are employed to recover the high-frequency coefficients. Eventually, the fused image is recovered by inverse NSCT. Both the visual effects and the numerical computation results after experiments indicate that the presented approach achieves much higher quality of image fusion, accelerates the calculations, enhances various targets and extracts more useful information.
Unraveling the Causal Mechanisms for Non-Grain Production of Cultivated Land: An Analysis Framework Applied in Liyang, China

The excessive use of cultivated land for non-grain production activities is considered a threat to grain security. This study presents an analysis framework on unraveling the causal mechanisms for non-grain production of cultivated land. We apply the analysis framework in Liyang, which is located in the Yangtze River Delta and is also an important “national grain base” county of China. We first determine four non-grain production categories as immediately recoverable (IMR), simple-engineering recoverable (SER), engineering recoverable (ENR), and irrecoverable (IR) based on the effect of non-grain activities on the degree of soil damage of the cultivated land, especially the difficulty of restoring the capacity for grain production. Then, we analyze the spatial pattern features for non-grain production of four given categories at the village scale. Furthermore, we reveal the mechanisms of the four categories using multiple linear regression modeling with geophysical, demographic, economic, and policy variables. The results show that the total non-grain area of cultivated land in Liyang is 28,158.38 hectares, and the non-grain rate is 48.09%, ranging from 10.59% to 96.75% among villages. The IMR, SER, ER, and IR rates are 11.81%, 17.76%, 15.07%, and 3.45%, respectively. There is also a significant neighborhood effect among the four categories, indicating that non-grain production activities have a stimulating effect on the surrounding operators of cultivated land. Farming conditions such as the proportion of irrigated farmland and economic variables such as the tourism scale have stronger effects on non-grain production than demographic variables. Policy variables, especially the cultivated land transfer policy, neither inhibit nor promote non-grain production. Based on these findings, we make policy suggestions for reducing non-grain production activities and protecting cultivated land. This analysis framework contributes to a new perspective for unraveling the causal mechanisms and making categorical governance decisions of non-grain production on cultivated land at the village level.
Pressure-induced high temperature superconductivity in H3X (X=As, Se, Br, Sb, Te and I)

The discovery of high critical temperature Tc superconductivity in highly compressed H3S has opened up the question of searching for strong electron-phonon coupling in the hydrides outside the transition metal series. In this work, we performed Linearized Augmented Plane Wave (LAPW) calculations for many different volumes in the Im-3m structure for H3X (X=As, Se, Br, Sb, Te and I), We then applied the multiple scattering-based theory of Gaspari and Gyorffy to obtain the Hopfield parameters and the McMillan-Allen-Dynes theory to estimate lambda and Tc. Based on our analysis, all materials considered show an increase of the Hopfield parameters with increasing pressure for both the H and X-element components, which is a key ingredient for the strong electron-phonon coupling and the high Tc. Our calculations for H3Se, in agreement with other studies, find a Tc~110K. For the other materials in our study we obtain Tc well below 100 K. However, according to both of our rigid band model and virtual crystal analysis, we predict a Tc~180 K for H3Br with a small amount of additional of hydrogen.
An Operator Based Approach to Irregular Frames of Translates

We consider translates of functions in L 2 ( R d ) along an irregular set of points, that is, { ϕ ( · − λ k ) } k ∈ Z —where ϕ is a bandlimited function. Introducing a notion of pseudo-Gramian function for the irregular case, we obtain conditions for a family of irregular translates to be a Bessel, frame or Riesz sequence. We show the connection of the frame-related operators of the translates to the operators of exponentials. This is used, in particular, to find for the first time in the irregular case a representation of the canonical dual as well as of the equivalent Parseval frame—in terms of its Fourier transform.
ANALISIS KESUKSESAN SISTEM INFORMASI MANAJEMEN DAERAH (SIMDA) BERDASARKAN MODEL DELONE DAN MCLEAN 2003 (STUDI PADA SATUAN KERJA PERANGKAT DAERAH KOTA LANGSA)

The purpose of this study was to analyze the SIMDA application using Delone and Mclean (2003) theory. The variables in the Delone and Mclean (2003) model are system quality, information quality, service quality, and intention to use in user satisfaction. The population in this study were all Regional Work Units (SKPD) in the Langsa City area of Aceh. The sampling technique of this study used non-probability sampling. Respondents who became the object of this study were the parties most responsible for the SIMDA so that 76 respondents. Data analysis using multiple linear regression with SPSS 21. The results of this study indicate that (1) system quality, information quality, service quality, and user interest simultaneously affect user satisfaction, (2) system quality partially affects user satisfaction, (3) information quality partially affects user satisfaction, (4) service quality partially affects user satisfaction, (5) user interest partially affects user satisfaction. The results indicate that the SIMDA application is quite successful.
Model independent approach to the dark energy equation of state

The consensus of opinion in cosmology is that the Universe is currently undergoing a period of accelerated expansion. With current and proposed high precision experiments it offers the hope of being able to discriminate between the two competing models that are being suggested to explain the observations, namely a cosmological constant or a time dependent ``quintessence'' model. The latter suffers from a plethora of scalar field potentials all leading to similar late time behavior of the universe and, hence, to a lack of predictability. In this paper, we develop a model independent approach which simply involves parametrizing the dark energy equation of state in terms of known observables. This allows us to analyze the impact dark energy has had on cosmology without the need to refer to particular scalar field models and opens up the possibility that future experiments will be able to constrain the dark energy equation of state in a model independent manner.
Gas‐Monitor Detector for Intense and Pulsed VUV/EUV Free‐Electron Laser Radiation

In the framework of current developments of new powerful VUV and EUV radiation sources, like VUV free‐electron‐lasers or EUV plasma sources for 13‐nm lithography, we developed a gas‐monitor detector in order to measure the photon flux of highly intense and extremely pulsed VUV and EUV radiation in absolute terms. The device is based on atomic photoionization of a rare gas at low particle density. Therefore, it is free of degradation and almost transparent, which allows the detector to be used as a continuously working beam‐intensity monitor. The extended dynamic range of the detector allowed its calibration with relative standard uncertainties of 4% in the Radiometry Laboratory of the Physikalisch‐Technische Bundesanstalt at the electron‐storage ring BESSY II in Berlin using spectrally dispersed synchrotron radiation at low photon intensities and its utilization for absolute photon flux measurements of high power sources. In the present contribution, we describe the design of the detector and its applicat.
The Effect of CSR Policy on Earnings Management Behavior: Evidence from Visegrad Publicly Listed Enterprises

A corporate socially responsible-focused approach adds value to a firm in the form of financial benefits in addition to improving its corporate image. To meet the demands of various stakeholders, including consumers, employees, and shareholders, and to produce high-quality financial reporting, some managers participate in CSR initiatives. The investigation of the relationship between corporate social responsibility and earnings management in publicly listed Visegrad companies is the main aim of the paper. The purpose is to identify the correlation between the CSR concept (measured by ESG score) and earnings management behavior determined by discretionary accrual levels (using the modified Jones model). To ascertain the association between CSR and earnings/discretionary accrual levels or to describe the major changes in the development of these variables, several statistical techniques were applied (correlation analysis, one-way ANOVA, and one-way ANOVA with repeated measures). As this is a pioneering study in the Visegrad environment (analyzing 35 publicly listed enterprises reporting ESG score), the research findings may have significant policy implications for decision-makers, regulators, auditors, and investors in their efforts to restrict earnings management techniques and enhance the quality of financial reporting.
Unsupervised change detection in multi-modal SAR images using CycleGAN

Many Change Detection (CD) methods exploit the bi-temporal multi-modal data derived by multiple sensors to find the changes effectively. State-of-the-Art CD methods define features with a common domain between the multi-modal data by normalizing input images or ad hoc feature extraction/selection methods. Deep Learning (DL) CD methods automatically learn features with a common domain during the training or adapt the features derived by multi-modal data. However, CD methods focusing on multi-sensor multi-frequency SAR data are still poorly investigated. We propose a DL CD method that exploits a Cycle Generative Adversarial Network (CycleGAN) to automatically learn and extract multi-scale feature maps in a domain common to the input multifrequency multi-sensor SAR data. The feature maps are learned, during unsupervised training, by generators that aim to transform the input data domain into the target one while preserving the semantic information and aligning the feature domain. We process the multi-sensor multi-frequency SAR data with the trained generators to produce bi-temporal multi-scale feature maps that are compared to enhance changes. A standard-deviation-based feature selection is applied to keep only the most informative comparisons and reject the ones with poor change information. The multi-scale comparisons are used for a detail preserving CD. Preliminary experimental results conducted on bi-temporal SAR data acquired by Cosmo-SkyMed and SAOCOM on the urban area of Milan, Italy, in January 2020 and August 2021 provided promising results.
Tri-state Buffer: Magnetic Vortex Transistor Based Logic Devices.

Magnetic analogue of electronic gates are advantageous in many ways. There is no electron leakage, higher switching speed and more energy saving in a magnetic logic device compared to a semiconductor one. Recently, we proposed a magnetic vortex transistor and fan-out out devices based on carefully coupled magnetic vortices in isolated nanomagnetic disks. Here, we demonstrate a new type of magnetic logic gate based upon asymmetric vortex transistor by using micromagnetic simulation. Depending upon two main features (topology) of magnetic vortex, chirality and polarity, the network can behave like a tri-state buffer. Considering the asymmetric magnetic vortex Transistor as a unit, the logic gate has been formed where two such transistors are placed parallel and another one is placed at the output. Magnetic energy given in the input transistors is transferred to the output transistor with giant amplification, due to the movement of antivortex solitons through the magnetic stray field. The loss and gain of energy at the output transistor can be controlled only by manipulating the polarities of the middle vortices in input transistors. Due to the asymmetric energy transfer of the antivortex solitons, we have shown successful fan-in operation in this topologically symmetric system. A tri-state buffer gate with fan-in of two transistors can be formed. This gate can be used as a Switch to the logic circuit and it has technological importance for energy transfer to large scale vortex networks.
Optically induced Lifshitz transition in bilayer graphene

It is shown theoretically that the renormalization of the electron energy spectrum of bilayer graphene with a strong high-frequency electromagnetic field (dressing field) results in the Lifshitz transition - the abrupt change in the topology of the Fermi surface near the band edge. This effect substantially depends on the polarization of the field: The linearly polarized dressing field induces the Lifshitz transition from the quadruply-connected Fermi surface to the doubly-connected one, whereas the circularly polarized field induces the multicritical point, where the four different Fermi topologies may coexist. As a consequence, the discussed phenomenon creates physical basis to control the electronic properties of bilayer graphene with light.
Pseudospectral Algorithms for Solving Nonlinear Schroedinger Equation in 3D

Three pseudospectral algorithms are described (Euler, leapfrog and trapez) for solving numerically the time dependent nonlinear Schroedinger equation in one, two or three dimensions. Numerical stability regions in the parameter space are determined for the cubic nonlinearity, which can be easily extended to other nonlinearities. For the first two algorithms, maximal timesteps for stability are calculated in terms of the maximal Fourier harmonics admitted by the spectral method used to calculate space derivatives. The formulas are directly applicable if the discrete Fourier transform is used, i.e. for periodic boundary conditions. These formulas were used in the relevant numerical programs developed in our group.
Multifield stochastic particle production: beyond a maximum entropy ansatz

We explore non-adiabatic particle production for Nf coupled scalar fields in a time-dependent background with stochastically varying effective masses, cross-couplings and intervals between interactions. Under the assumption of weak scattering per interaction, we provide a framework for calculating the typical particle production rates after a large number of interactions. After setting up the framework, for analytic tractability, we consider interactions (effective masses and cross couplings) characterized by series of Dirac-delta functions in time with amplitudes and locations drawn from different distributions. Without assuming that the fields are statistically equivalent, we present closed form results (up to quadratures) for the asymptotic particle production rates for the Nf=1 and Nf=2 cases. We also present results for the general Nf >2 case, but with more restrictive assumptions. We find agreement between our analytic results and direct numerical calculations of the total occupation number of the produced particles, with departures that can be explained in terms of violation of our assumptions. We elucidate the precise connection between the maximum entropy ansatz (MEA) used in Amin & Baumann (2015) and the underlying statistical distribution of the self and cross couplings. We provide and justify a simple to use (MEA-inspired) expression for the particle production rate, which agrees with our more detailed treatment when the parameters characterizing the effective mass and cross-couplings between fields are all comparable to each other. However, deviations are seen when some parameters differ significantly from others. We show that such deviations become negligible for a broad range of parameters when Nf≫ 1.