Miracle-dz/UniFAR-FTUs huggingface dataset:
Noncollinear gating of laser-plasma-driven attosecond pulses without spectral filtering

Intense attosecond scale pulses of extreme-ultraviolet and soft X-ray light can be generated from plasma surfaces driven relativistically by intense laser pulses. The temporal profile consists of a train of pulses separated by the laser’s optical period and manifests in the spectral domain as harmonics of the laser frequency. Isolating individual attosecond pulses is a key challenge for applications of these sources to time-resolved experiments for attosecond science and plasma-based sources allow the use of ultra-high energies and intensities that can enable fully attosecond scale pump-probe measurements. Results are presented here for numerical Particle-In-Cell simulations of a scheme to angularly sweep the pulses so that one is temporally gated out from the others in the reflected direction. Using two identical laser pulses that are incident noncollinearly on the surface with a time delay causes the instantaneous wavefront to sweep between each of them with the attosecond pulses also being swept in their emission angle accordingly. This method naturally separates out the remaining reflected laser energy due to the angular gap between the incident pulses negating the need for spectral filtering after the interaction. We demonstrate clear gating of a single pulse along the reflected axis in both 2D and 3D simulations and discuss the effect of spectral isolation from the laser frequency. We extend the investigation to further examine techniques to improve the temporal gating by tailoring the laser and target properties.
Progress in Hybrid Temporal LES (plenary lecture)

In order to favour the modelling of the subgrid stresses in continuous hybrid RANS/LES methods, the comparison of the solutions with experimental or DNS databases, and eventually the understanding of the phenomenology observed in the resolved motion, defining a rigorous formalism for such methods is highly desirable. Empirical methods to bridge RANS and LES suffer from the fact that RANS and LES are based on generally inconsistent operators, statistical averaging and spatial filtering, respectively [9]. The present paper summarises recent work that tries to reconcile the two methodologies by defining consistent operators, based on temporal filtering, and provides examples of HTLES (Hybrid Temporal LES) models that can be derived based on this formalism.
An Investigation of Blazars without Redshifts: Not a Missing Population at High Redshift

We investigate a sample of 622 blazars with measured fluxes at 12 wavebands across the radio-to-gamma-ray spectrum but without spectroscopic or photometric redshifts. This sample includes hundreds of sources with newly analyzed X-ray spectra reported here. From the synchrotron peak frequencies, estimated by fitting the broadband spectral energy distributions (SEDs), we find that the fraction of high-synchrotron-peaked blazars in these 622 sources is roughly the same as in larger samples of blazars that do have redshifts. We characterize the no-redshift blazars using their infrared colors, which lie in the distinct locus called the WISE blazar strip, then estimate their redshifts using a KNN regression based on the redshifts of the closest blazars in the WISE color–color plot. Finally, using randomly drawn values from plausible redshift distributions, we simulate the SEDs of these blazars and compare them to known blazar SEDs. Based on all these considerations, we conclude that blazars without redshift estimates are unlikely to be high-luminosity, high-synchrotron-peaked objects, which had been suggested in order to explain the “blazar sequence”—an observed trend of SED shape with luminosity—as a selection effect. Instead, the observed properties of no-redshift blazars are compatible with a causal connection between jet power and electron cooling, i.e., a true blazar sequence.
Green intellectual capital measurement in the hotel industry: The developing country study

The going green agenda or environmental protection has gained the attention of the industries. The tourism sector nowadays is not just a conservative industry that provides tourism activities but is now associated with sustainable practices (Bombiak, 2021). Hotels are very severely affected by the COVID-19 pandemic. Green intellectual capital (GIC) combines intellectual capital (IC), environmental knowledge, and awareness. IC is crucial in a firm and efficiently utilizing it will help enhance any organization’s performance. There is limited GIC measurement as not many researchers have investigated GIC. This study aims to produce a GIC model for hotels to practice in their daily operation to enhance their performance. The current study employs a case study approach where five interviews were conducted with different personnel in Malaysia’s tourism and hotel sector. The study identified eighteen indicators for the GIC model. The GIC model aids the firm in complying with environmental regulations, creating value for the firm, and meeting customers’ requirements on environmental issues
The least eigenvalues of nonhomogeneous degenerated quasilinear eigenvalue problems

We prove the existence of the least positive eigenvalue with a corresponding nonnegative eigenfunction of the quasilinear eigenvalue problem \align-\operatorname{div}(a(x,u)|\nablau|^{p-2}\nabla u) = &\lambda b(x,u)|u|^{p-2}u \quad\text{ in } \Omega, u = &0 \hskip2cm\text{ on } \partial\Omega, \endalign where $\Omega$ is a bounded domain, $p>1$ is a real number and $a(x,u)$, $b(x,u)$ satisfy appropriate growth conditions. Moreover, the coefficient $a(x,u)$ contains a degeneration or a singularity. We work in a suitable weighted Sobolev space and prove the boundedness of the eigenfunction in $L^\infty(\Omega)$. The main tool is the investigation of the associated homogeneous eigenvalue problem and an application of the Schauder fixed point theorem.
Shear test on viscoelastic granular material using Contact Dynamics simulations

By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.
Convergence of binomial to normal: multiple proofs

This article presents four different proofs of the convergence of the Binomial ( , ) B n p distribution to a limiting normal distribution, n. These contrasting proofs may not be all found together in a single book or an article in the statistical literature. Readers of this article would find the presentation informative and especially useful from the pedagogical standpoint. This review of proofs should be of interest to teachers and students of senior undergraduate courses in probability and statistics.
New microscopic image sequence‐driven cell deformation model

It is of great significance that making quantitative description and analysis of the cell morphological change to explore physiological or pathological status of the life. To achieve the cells morphological changes of quantitative description, the authors constructed a cell deformation model based on microscopic image sequence here. Based on the graph regularisation and structured matrix decomposition, the high-dimensional shape space is represented by the linear combination of the lowdimension subshape space, so that the authors get a quantitative indicator which represents the degree of cell deformation– deformation factor. In order to verify the validity of the authors’ model, a deformation feature extraction experiment was performed on three groups of stem cell image sequence with different deformation degree. Compared with other three common quantitative methods of deformation, the authors’ model describes the cell morphological changes more comprehensively, and has better adaptability and stability for describing the diversity of cell movements.
Effectiveness and safety of upadacitinib – data from real clinical practice in Bulgaria

Objectives: Aim of the study was to assess the therapeutic efficacy and safety of upadacitinib in Rheumatoid arthritis patients with moderate to high disease activity in real-world clinical practice and to identify predictors of therapeutic success. Materials and methods: A retrospective single-center study was performed in RA patients treated with upadacitinib 15 mg daily. Demographic and clinical indicators were analyzed. The effectiveness and safety of the medication were evaluated over a six-month period. Disease activity was assessed with index-based scores. The primary endpoint was defined as low disease activity over a six-month treatment period with upadacitinib 15 mg/day (DAS28CRP ≤ 3.2, CDAI ≤ 10 and SDAI ≤ 11). Results: 41 patients were included, mean age 56.56 years (± 13.4), with long-standing RA (8 years ± 5.8), mostly female (80.5%). 19.5% of them were obese (BMI ≥ 30 kg/m2), 80.5% had osteoarthritis and 58.5% - hypertensive disease. Erosive arthritis was observed in 41.5% of patients and 61% had functional class III motor deficit. "Bio-naïve" were 58.5%, the rest had previous experience with biologic therapy. Upadacitinib was used as monotherapy in 90% of patients and in combination with Methotrexate in 10%. There was a significant reduction in the painful and swollen joint counts, VAS and CRP six months after starting treatment with upadacitinib. Low disease activity was achieved by a significant proportion of patients (DAS28CRP-70.7%, CDAI-60.5% and SDAI 63.2%). Therapeutic outcome was not determined by demographics, clinical factors, comorbidities, or prior biologic treatment. Increase in liver enzymes (n=3), decrease in hemoglobin levels (n=2), and urinary tract infection (n=2) were the adverse events recorded over the six-month treatment period. One patient died from COVID-19. Conclusion: A significant proportion of RA patients on treatment with upadacitinib 15 mg was able to achieve the therapeutic target in real clinical settings. No predictors of therapeutic efficacy were found. The registered side effects do not differ from the safety profile of the medication.
Trends on band alignments: Validity of Anderson's rule in SnS2- and SnSe2-based van der Waals heterostructures

Van der Waals (vdW) heterostructures are promising candidates for building blocks in novel electronic and optoelectronic devices with tailored properties, since their electronic action is dominated by the band alignments upon their contact. In this work, we analyze 10 vdW heterobilayers based on tin dichalcogenides by first-principles calculations. Structural studies show that all systems are stable, and that commensurability leads to smaller interlayer distances. Using hybrid functional calculations, we derive electronic properties and band alignments for all the heterosystems and isolated two-dimensional (2D) crystals. Natural band offsets are derived from calculated electron affinities and ionization energies of 11 freestanding 2D crystals. They are compared with band alignments in true heterojunctions, using a quantum mechanical criterion, and available experimental data. For the hBN/SnSe2 system, we show that hBN suffers an increase in band gap, while leaving almost unchanged the electronic properties of SnSe2 Similarly, MX2 (M = Mo, W; X = S, Se) over SnX2 preserve the natural discontinuities from each side of the heterobilayer. Significant charge transfer occurs in junctions with graphene, which becomes p-doped and forms an Ohmic contact with SnX2. Zirconium and hafnium dichalcogenides display stronger interlayer interactions, leading to larger shifts in band alignments with tin dichalcogenides. Significant orbital overlap is found, which creates zero conduction band offset systems. The validity of the Anderson electron affinity rule is discussed. Failures of this model are traced back to interlayer interaction, band hybridization, and quantum dipoles. The systematic work sheds light on interfacial engineering for future vdW electronic and optoelectronic devices. (AU)
Nonparametric instrumental variable derivative estimation

ABSTRACT The focus of this paper is the nonparametric estimation of the marginal effects (i.e. first partial derivatives) of an instrumental regression function ϕ defined by conditional moment restrictions that stem from a structural econometric model , and involve endogenous variables Y and Z and instruments W. The derivative function is the solution of an ill-posed inverse problem and we propose an estimation procedure based on Landweber–Fridman regularisation. We provide theoretical underpinnings of the proposed approach, examine finite-sample performance, and consider an illustrative application.
An asymptotic approach to one-dimensional model of nonlinear thermoelasticity at low temperatures and small strains*

ABSTRACT A one-dimensional nonlinear homogeneous isotropic thermoelastic model with an elastic heat flow at low temperatures and small strains is analyzed using the method of weakly nonlinear asymptotics. For such a model, both the free energy and the heat flux vector depend not only on the absolute temperature and strain tensor but also on an elastic heat flow that satisfies an evolution equation. The governing equations are reduced to a matrix partial differential equations, and the associated Cauchy problem with a weakly perturbed initial condition is solved. The solution is given in the form of a power series with respect to a small parameter, the coeﬃcients of which are functions of a slow variable that satisfy a system of nonlinear second-order ordinary differential transport equations. A family of closed-form solutions to the transport equations is obtained. For a particular Cauchy problem in which the initial data are generated by a closed-form solution to the transport equations, the asymptotic solution in the form of a sum of four traveling thermoelastic waves admitting blow-up amplitudes is presented.
Natural convection of nanofluids in a cavity: criteria for enhancement of nanofluids

Purpose The purpose of this study is to theoretically analyze the laminar free convection heat transfer of nanofluids in a square cavity. The sidewalls of the cavity are subject to temperature difference, whereas the bottom and top are insulated. Based on the available experimental results in the literature, two new non-dimensional parameters, namely, the thermal conductivity parameter (Nc) and dynamic viscosity parameter (Nv) are introduced. These parameters indicate the augmentation of the thermal conductivity and dynamic viscosity of the nanofluid by dispersing nanoparticles. Design/methodology/approach The governing equations are transformed into non-dimensional form using the thermo-physical properties of the base fluid. The obtained governing equations are solved numerically using the finite element method. The results are reported for the general non-dimensional form of the problem as well as case studies in the form of isotherms, streamlines and the graphs of the average Nusselt number. Using the concept of Nc and Nv, some criteria for convective enhancement of nanofluids are proposed. As practical cases, the effect of the size of nanoparticles, the shape of nanoparticles, the type of nanoparticles, the type of base fluids and working temperature on the enhancement of heat transfer are analyzed. Findings The results show that the increase of the magnitude of the Rayleigh number increases of the efficiency of using nanofluids. The type of nanoparticles and the type of the base fluid significantly affects the enhancement of using nanofluids. Some practical cases are found, in which utilizing nanoparticles in the base fluid results in deterioration of the heat transfer. The working temperature of the nanofluid is very crucial issue. The increase of the working temperature of the nanofluid decreases the convective heat transfer, which limits the capability of nanofluids in decreasing the size of the thermal systems. Originality/value In the present study, a separation line based on two non-dimensional parameters (i.e. Nc and Nv) are introduced. The separation line demonstrates a boundary between augmentation and deterioration of heat transfer by using nanoparticles. Indeed, by utilizing the separation lines, the convective enhancement of using nanofluid with a specified Nc and Nv can be simply estimated.
Convergence Analysis of the Ensemble Kalman Filter for Inverse Problems: the Noisy Case

We present an analysis of the ensemble Kalman filter for inverse problems based on the continuous time limit of the algorithm. The analysis of the dynamical behaviour of the ensemble allows to establish well-posedness and convergence results for a fixed ensemble size. We will build on the results presented in [Schillings, Stuart 2017] and generalise them to the case of noisy observational data, in particular the influence of the noise on the convergence will be investigated, both theoretically and numerically.
PRICING PERPETUAL TIMER OPTION UNDER THE STOCHASTIC VOLATILITY MODEL OF HULL–WHITE

The valuation of perpetual timer options under the Hull–White stochastic volatility model is discussed here. By exploring the connection between the Hull–White model and the Bessel process and using time-change techniques, the triple joint distribution for the instantaneous volatility, the cumulative reciprocal volatility and the cumulative realized variance is obtained. An explicit analytical solution for the price of perpetual timer call options is derived as a Black–Scholes–Merton-type formula.
The effect of fibre swelling on fluid flow in cotton fabrics: An experimental study

: Design of hygiene products such as sanitary napkins, diapers, etc. is heavily dependent on the liquid absorption performance of fabrics. As ﬁbres swell upon liquid absorption, their liquid absorption performance changes. Understanding the ﬂow through porous media under swelling conditions has important implications for product design and has yet to be elucidated fully. The goal of our research was to study the effect of ﬁbre swelling experimentally. Cotton is selected as the test fabric as it is commonly used in most hygiene applications. Under swelling conditions, the effect of swelling on individual ﬁbres, porosity, permeability, and performance of the cotton fabric is analysed. Findings showed that upon water absorption, the ﬁbre diameter increased by 10%, porosity decreased by 11%, and permeability decreased by 60% under fully swollen conditions. The porosity reduction is also predicted analytically using the data obtained from the ﬁbre swelling measurements. In contrast, predictions of commonly used analytical models showed only a 30% reduction in the porosity. To correct this, two new correction factors to account for effects of inter-ﬁbre interactions on the total swelling rate of fabric are proposed. The performance measures of cotton samples under swelling conditions indicated that advancement of the ﬂow front on the lower face was more dominant than the upper face of the sample possibly related to gravity. These experimental data improve our understanding of wicking ﬂow which can help to improve the design of hygiene products and to develop more realistic computational ﬂuid dynamics models.
Highly deformed grain: from the Hertz contact limitation to a new strain field description in 2D

Most of the 2D studies on granular materials consider an assembly of cylindrical particles in the small deformation regime. Investigating the range of validity of the small deformation hypothesis is therefore of crucial importance in order to determine the quantitative relevance of the predictions emerging from these 2D studies. We introduce here a novel experimental set-up based on high resolution imaging and image correlation, and capable of measuring the strain field inside the particles with a cutting edge accuracy. We measure the strain field inside a unique circular cylindrical elastic particle undergoing an uniaxial compression. The significant deviations arising from the comparison with the predictions of the small deformation limit predicted by the Hertz’s theory, and numerical simulations, give insight to improve the modeling of 2D granular materials.
Business Cycle Synchronization of CEE Countries with the Euro Area. Between Core and Periphery

In this study, we aimed to assess the degree of business cycle synchronisation in five CEE countries that have not adopted the euro (Romania, Bulgaria, Hungary, Poland and the Czech Republic), from the perspective of investigating similar developments with the three most important countries of the monetary union (Germany, France and Italy), respectively, with the peripheral countries most affected by the sovereign debt crisis (Greece, Portugal and Spain). The results confirm that membership of the monetary union does not automatically reduce the potential for asymmetric shocks, as in the case of peripheral countries, and that CEE countries do not have a similar path of improving business cycle synchronisation, with Romania and Bulgaria being closer to the Greek experience.
Causal Inference and Conditional Independence Testing with RCoT

—Conditional Independence (CI) testing is a crucial operation in causal model discovery and validation. Effectively performing this requires a linearly scalable and robust algorithm and its implementation. Previous techniques, such as cross-correlation, a linear method; Kernel Conditional Independence Test (KCIT,) and a kernel-based algorithm, do not scale well with dataset size and pose a bottleneck for CI algorithms. An improved version of kernel-based algorithms which use linear mapping to decrease computational time is the Randomized conditional Correlation Test (RCoT) and Randomized Conditional Independence Test (RCIT). This paper describes their use and implementation in Python. This paper then compares the time complexity of the RCoT algorithm with a previously implemented Discretization-based algorithm Probspace. The results show that the accuracy of the previous and current models is similar, but the time taken to get these results has been reduced by 50%. The implemented algorithm takes about 3s to run the testcases (the data used and testcases generated are described in Section IV-C).
Single and multiple Auger decay processes from the N e + 1 s − 1 2 p − 1 n p shake-up states studied with a multielectron coincidence method

The single, double, and triple Auger decay processes from the $1{s}^{\ensuremath{-}1}2{p}^{\ensuremath{-}1}np$ shake-up states of Ne have been studied with a multielectron coincidence method. It is revealed that the Rydberg electron promoted in the initial photoionization step generally acts as a spectator both in the single and double Auger decays. The single Auger decay predominantly produces three-hole one-particle final states while leaving the Rydberg electron virtually unchanged. In the cascade double Auger paths, the Rydberg electron is a spectator in the first step of the cascade process but is subsequently released in the second step, leading to the formation of three-hole final states. The direct paths of double Auger decays, which are much weaker than the cascade paths, produce preferably four-hole one-particle states due to the spectator behavior of the Rydberg electron. The distributions of the $\mathrm{N}{\mathrm{e}}^{4+}$ states populated by the triple Auger decays are also presented.