Miracle-dz/UniFAR-FTUs huggingface dataset:
Capital Structure and Firm Performance: Evidence of Egypt During COVID Pandemic

: Capital structure has gained considerable interest from businesses and academics in the financial management arena in the last decades. It has been realized that capital structure may affect corporate financial performance. Recent research shows that optimal capital structure could improve financial performance in some countries. Yet, the question of “how does capital structure dynamics affect financial performance during the Covid-19 pandemic” has not been thoroughly discussed and studied in Egypt. The empirical data were drawn from a sample of 667 observations for the period 2014-2021 in the Egyptian Stock Exchange. The mixed models are used to test the research hypotheses. The empirical results showed that there is a negative significant relationship between capital structure and financial performance measured by ROA, ROE and stock price. Additionally, there was a significant negative impact for the COVID on the financial performance either using market based or accounting-based measures. The research findings can be supported by the Pecking Order Theory; which suggests that the negative relationship is due to the high cost of borrowing in developing countries. Since firms are confronting with the default risk due to having higher loans and paying higher interest.
Fourth-order split monopole perturbation solutions to the Blandford-Znajek mechanism

The Blandford-Znajek (BZ) mechanism describes a physical process for the energy extraction from a spinning black hole (BH), which is believed to power a great variety of astrophysical sources, such as active galactic nuclei and gamma ray bursts. The only known analytic solution to the BZ mechanism is a split monopole perturbation solution up to O(a(2)), where a is the spin parameter of a Kerr black hole. In this paper, we extend the monopole solution to higher order similar to O(a(4)). We carefully investigate the structure of the BH magnetosphere, including the angular velocity of magnetic field lines Omega, the toroidal magnetic field B-phi, as well as the poloidal electric current I. In addition, the relevant energy extraction rate (E) over dot and the stability of this high-order monopole perturbation solution are also examined.
FLARE-ASSOCIATED TYPE III RADIO BURSTS AND DYNAMICS OF THE EUV JET FROM SDO/AIA AND RHESSI OBSERVATIONS

We present a detailed description of the interrelation between the Type III radio bursts and energetic phenomena associated with the flare activities in active region AR11158 at 07:58 UT on 2011 February 15. The timing of the Type III radio burst measured by the radio wave experiment on Wind/WAVE and an array of ground-based radio telescopes coincided with an extreme-ultraviolet (EUV) jet and hard X-ray (HXR) emission observed by SDO/AIA and RHESSI, respectively. There is clear evidence that the EUV jet shares the same source region as the HXR emission. The temperature of the jet, as determined by multiwavelength measurements by Atmospheric Imaging Assembly, suggests that Type III emission is associated with hot, 7 MK, plasma at the jet's footpoint.
The growth of galactic bulges through mergers in Λ cold dark matter haloes revisited – II. Morphological mix evolution

ABSTRACT The mass aggregation and merger histories of present-day distinct haloes selectedfrom the cosmological Millennium Simulations I and II are mapped into stellar massaggregation and galaxy merger histories of central galaxies by using empirical stellar-to-halo and stellar-to-gas mass relations. The growth of bulges driven by the galaxymergers/interactions is calculated analytically. The predicted bulge demographics atredshift z ∼ 0 is consistent with observations (Zavala et al. 2012). Here we presentthe evolution of the morphological mix (traced by the bulge-to-total mass ratio, B/T)as a function of mass up to z = 3. This mix remains qualitatively the same up toz∼1: B/T 60.1 galaxies dominate at low masses, 0.1 0.45 at large masses. At z >1, the fractions of disc-dominatedand bulgeless galaxies increase strongly, and by z ∼ 2 the era of pure disc galaxiesis reached. Bulge-dominated galaxies acquire such a morphology, and most of theirmass, following a downsizing trend. Since our results are consistent with several recentobservational studies of the morphological mix at diﬀerent redshifts, a ΛCDM-basedscenario of merger-driven bulge assembly does not seem to face signiﬁcant issues.However, if the stellar-to-halo mass relation evolves too little with redshift, then sometensions with observations appear.Keywords: galaxies: formation galaxies: evolution galaxies: high-redshift galaxies:bulges galaxies: interactions galaxies: structure.
Comet formation in collapsing pebble clouds. What cometary bulk density implies for the cloud mass and dust-to-ice ratio

Comets are remnants of the icy planetesimals that formed beyond the ice line in the Solar Nebula. Growing from micrometre-sized dust and ice particles to km-sized objects is, however, difficult because of growth barriers and time scale constraints. The gravitational collapse of pebble clouds that formed through the streaming instability may provide a suitable mechanism for comet formation. We study the collisional compression of cm-sized porous ice/dust-mixed pebbles in collapsing pebble clouds. For this, we developed a collision model for pebbles consisting of a mixture of ice and dust, characterised by their dust-to-ice mass ratio. Using the final compression of the pebbles, we constrain combinations of initial cloud mass, initial pepple porosity, and dust-to-ice ratio that lead to cometesimals which are consistent with observed bulk properties of cometary nuclei. We find that observed high porosity and low density of ~0.5 g/cc of comet nuclei can only be explained if comets formed in clouds with mass approximately M>1e18 g. Lower mass clouds would only work if the pebbles were initially very compact. Furthermore, the dust-to-ice ratio must be in the range of between 3 and 9 to match the observed bulk properties of comet nuclei. (abridged version)
Optimality of Contraction-Driven Crawling

We study a particular mechanism of cell motility allowing a precise formulation of the condition of optimal trade-off between performance and metabolic cost. In the model, a steadily crawling fragment is represented by a layer of active gel placed on a frictional surface and driven by contraction only. We find analytically the distribution of contractile elements (pullers) ensuring that the efficiency of self-propulsion is maximal. We then show that natural assumptions about advection and diffusion of pullers produce a distribution that is remarkably close to the optimal one and is qualitatively similar to the one observed in experiments on fish keratocytes. © 2014 American Physical Society.
Revisiting the universality of (multiple) star formation in present-day star formation regions

Populations of multiple stars inside clustered regions are known to change through dynamical interactions. The efficiency of binary disruption is thought to be determined by stellar density. King and collaborators recently investigated the multiplicity properties in young star forming regions and in the Galactic field. They concluded that stellar density-dependent modification of a universal initial binary population (the standard or null hypothesis model) cannot explain the observations. We re-visit their results, analyzing the data within the framework of different model assumptions, namely non-universality without dynamical modification and universality with dynamics. We illustrate that the standard model does account for all known populations if regions were significantly denser in the past. Some of the effects of using present-day cluster properties as proxies for their past values are emphasized and that the degeneracy between age and density of a star forming region can not be omitted when interpreting multiplicity data. A new analysis of the Corona Australis region is performed within the standard model. It is found that this region is likely as unevolved as Taurus and an initial density of $\approx190M_{\odot}\;pc^{-3}$ is required to produce the presently observed binary population, which is close to its present-day density.
Nonlinear Particle Acceleration and Thermal Particles in GRB Afterglows

The standard model for GRB afterglow emission treats the accelerated electron population as a simple power law, for . However, in standard Fermi shock acceleration, a substantial fraction of the swept-up particles do not enter the acceleration process at all. Additionally, if acceleration is efficient, then the nonlinear back-reaction of accelerated particles on the shock structure modifies the shape of the nonthermal tail of the particle spectra. Both of these modifications to the standard synchrotron afterglow impact the luminosity, spectra, and temporal variation of the afterglow. To examine the effects of including thermal particles and nonlinear particle acceleration on afterglow emission, we follow a hydrodynamical model for an afterglow jet and simulate acceleration at numerous points during the evolution. When thermal particles are included, we find that the electron population is at no time well fitted by a single power law, though the highest-energy electrons are; if the acceleration is efficient, then the power-law region is even smaller. Our model predicts hard–soft–hard spectral evolution at X-ray energies, as well as an uncoupled X-ray and optical light curve. Additionally, we show that including emission from thermal particles has drastic effects (increases by factors of 100 and 30, respectively) on the observed flux at optical and GeV energies. This enhancement of GeV emission makes afterglow detections by future γ-ray observatories, such as CTA, very likely.
SCREENING OF CELLULASE GENES AND DEGRADING ACTIVITIES OF TRICHODERMA ASPERELLUM VIA SOLID-STATE FERMENTATION OF RICE STRAW AND SUGARCANE BAGASSE

: PCR based on specific primers was employed for detection of important cellulase genes (CBH1, EGI and EGII genes) in the genomes of eighteen Trichoderma isolates recovered from Egyptian soil rich with the agricultural wastes. The Trichoderma asperellum (Tm4) isolate that exhibited the highest hydrolysis zone was selected for evaluation their cellulase activities via solid state fermentation on media supplemented with rice straw and sugarcane bagasse as sole carbon sources. The results showed that the highest FPase, CMCase, Xylanase activities were obtained when rice straw was used as sole carbon source as compared to sugarcane bagasse. In addition, the cellulase activities were better in each the untreated rice straw and sugarcane bagasse than the alkali pretreated rice straw and sugarcane bagasse. The C/N ratio was decreased, while the weight loss was increased in the treatments inoculated with Trichoderma as compared to control. Moreover, the pH values of each alkali pretreated rice straw and sugar cane bagasse were shifted toward the acidity. Meanwhile, the pH values of untreated rice straw were shifted toward alkali state.
NUMERICAL SIMULATION OF HOT ACCRETION FLOWS. II. NATURE, ORIGIN, AND PROPERTIES OF OUTFLOWS AND THEIR POSSIBLE OBSERVATIONAL APPLICATIONS

Hydrodynamical (HD) and magnetohydrodynamical (MHD) numerical simulations of hot accretion flows have indicated that the inflow accretion rate decreases inward. Two models have been proposed to explain this result. In the adiabatic inflow–outflow solution (ADIOS), this is because of the loss of gas in the outflow. In the alternative convection-dominated accretion flow model, it is thought that the flow is convectively unstable and gas is locked in convective eddies. We investigate the nature of the inward decrease of the accretion rate using HD and MHD simulations. We calculate various properties of the inflow and outflow such as temperature and rotational velocity. Systematic and significant differences are found. These results suggest that the inflow and outflow are not simply convective turbulence; instead, systematic inward and outward motion (i.e., real outflow) must exist. We have also analyzed the convective stability of MHD accretion flows and found that they are stable. These results favor the ADIOS scenario. We suggest that the mechanisms of producing outflow in HD and MHD flows are the buoyancy associated with the convection and the centrifugal force associated with the angular momentum transport mediated by the magnetic field, respectively. The latter is similar to the Blandford & Payne mechanism but no large-scale open magnetic field is required. We discuss some possible observational applications, including the Fermi bubble in the Galactic center and winds in active galactic nuclei and black hole X-ray binaries.
The outcomes and predictors associated with prolonged weaning of postoperative patients requiring mechanical ventilation in general wards

Background & Objective: Many of the postoperative patients may require ventilatory management. In a resource-limited country, not all of them may find a place in intensive care units (ICUs), and may need to be ventilated in general wards till they are weaned off or shifted to ICU. Our primary objective was to describe weaning outcomes of such patients in the general wards, and the secondary objective was to assess predictors associated with prolonged weaning in these patients. Methodology: This retrospective study was conducted in a tertiary care hospital in Thailand. From January 2014 to December 2019, we identified 553 patients who received postoperative mechanical ventilation in general wards after non-cardiac surgeries. The weaning characteristics and the factors associated with prolonged ventilation and weaning were recorded. Results: Incidence of short (≤ 24 h), difficult (> 1, but ≤ 7 days), prolonged (> 7 days) and no weaning were 53.0%, 28.6%, 15.0% and 3.4%, respectively. The predictors of prolonged weaning were postoperative Glasgow Coma Scale ≤ 8 [adjusted odds ratio (OR) 11.34, 95% confidence interval (CI) 5.05-25.47], repeated surgeries (OR 7.38, 95% CI 3.67-14.83), totally dependent functional status (OR 3.22, 95% CI 1.35-7.72), and age more than 65 y (OR 2.35 95% CI 1.29-4.25). Reintubation rate was 5.1%. Accidental extubation rate was 2.3%. Incidence of ventilator associated pneumonia was 11.6%. The 30-day mortality rate was 6%. Conclusion: Weaning processes in general wards were mostly terminated within 24 h; however, 15% of patients experienced prolonged weaning. Postoperative Glasgow Coma Scale ≤ 8, repeated surgeries, totally dependent functional status, and age more than 65 y were the predictors of prolonged weaning.
A dynamical model for the formation of gas rings and episodic starbursts near galactic centres

We develop a simple dynamical model for the evolution of gas in the centres of barred spiral galaxies, using the Milky Way's Central Molecular Zone (CMZ, i.e., the central few hundred pc) as a case study. We show that, in the presence of a galactic bar, gas in a disc in the central regions of a galaxy will be driven inwards by angular momentum transport induced by acoustic instabilities within the bar's inner Lindblad resonance. This transport process drives turbulence within the gas that temporarily keeps it strongly gravitationally stable and prevents the onset of rapid star formation. However, at some point the rotation curve must transition from approximately flat to approximately solid body, and the resulting reduction in shear reduces the transport rates and causes gas to build up, eventually producing a gravitationally-unstable region that is subject to rapid and violent star formation. For the observed rotation curve of the Milky Way, the accumulation happens $\sim 100$ pc from the centre of the Galaxy, in good agreement with the observed location of gas clouds and young star clusters in the CMZ. The characteristic timescale for gas accumulation and star formation is of order $10-20$ Myr. We argue that similar phenomena should be ubiquitous in other barred spiral galaxies.
The whole is greater than the sum of the parts: on the possibility of purely statistical interpretations of quantum theory

The Pusey-Barrett-Rudolph theorem (PBR) claims to rule out the possibility of a purely statistical interpretation of the quantum state under an assumption of how to represent independent operations in any hidden variable model. We show that PBR's assumption of independence encodes an assumption of local causality, which is already known to conflict with the predictions of quantum theory via Bell-type inequalities. We devise a weaker formulation of independence within a general hidden variable model that is empirically indistinguishable from the PBR assumption in situations where certain hidden variables are inaccessible. Under this weaker principle we are able to construct an explicit hidden variable model that is purely statistical and also reproduces the quantum predictions. Our results suggest that the assumption of a purely statistical interpretation is actually an innocent bystander in the PBR argument, rather than the driving force behind their contradiction.
Comparing Firefighters' Perceived Workload Using 2D vs. 3D Building Plans to Support Emergency Response Preplanning in a Simulated Fire Scenario

Firefighters rely on visual information to make tactical decisions during structure fire events. Consequently, user interface design for public safety requires a comprehensive understanding of how these visual cues impact performance in terms of expertise and domain knowledge, as well as cognitive load. However, very few studies have captured baseline measures (e.g., subjective workload) associated with the use of pre-incident planning, the phase prior to deciding how to extinguish the fire. Virtual environments and 3D modeling have been suggested as a tool that can better support the exploration of emerging technology to better support pre-incident planning practices. Sixty-four (n = 64) North American firefighters participated in this study. Our work focuses on providing baseline data to define effective ways to present building and hazard information to incident commanders using both current systems (e.g., 2D diagrams) and emerging technologies (e.g., 3D models, virtual reality, augmented reality).
Stabilization of multibeam necklace solitons in circular arrays with spatially modulated nonlinearity

We consider necklace solitons supported by circular waveguide arrays with out-of-phase modulation of nonlinearity and linear refractive index. Such two-dimensional necklace solitons appear as rings of multiple out-of-phase bright spots. We show that necklace solitons are stable if their peak intensity is low or moderate and that the domain of stability shrinks with increasing nonlinearity modulation depth. However, we find that the stability domains expand with increasing number of necklace spots.
Many-Body Delocalization in the Presence of a Quantum Bath

Closed generic quantum many-body systems may fail to thermalize under certain conditions even after long times, a phenomenon called many-body localization (MBL). Numerous studies have left no doubt about the stability of the MBL phase in strongly disordered one-dimensional systems. However, the situation is much less clear when a small part of the system is ergodic, a scenario which also has important implications for the existence of many-body localization in higher dimensions. Here we address this question experimentally using a large-scale quantum simulator of ultracold bosons in a two-dimensional optical lattice. We prepare two-component mixtures of varying relative population and implement a disorder potential which is only experienced by one of the components. The second non-disordered "clean" component plays the role of a small quantum bath of adjustable size that is collisionally coupled to the "dirty" component. Our experiments provide evidence that MBL is remarkably stable in 2D and can even survive in the presence of a small bath for our observed long timescales. A too large bath, however, ultimately leads to the destruction of MBL.
On the sensitivity of CTA to gamma-ray boxes from multi-TeV dark matter

Collider, direct and indirect searches for dark matter have typically little or no sensitivity to weakly interacting massive particles (WIMPs) with masses above a few TeV. This rather unexplored regime can however be probed through the search for distinctive gamma-ray spectral features produced by the annihilation of WIMPs at very high energies. Here we present a dedicated search for gamma-ray boxes—sharp spectral features that cannot be mimicked by astrophysical sources—with the upcoming Cherenkov Telescope Array (CTA). Using realistic projections for the instrument performance and detailed background modelling, a profile likelihood analysis is implemented to derive the expected upper limits and sensitivity reach after 100 h of observations towards a 2°×2° region around the Galactic centre. Our results show that CTA will be able to probe gamma-ray boxes down to annihilation cross sections of 10−27−10−26 cm3/s up to tens of TeV. We also identify a number of concrete particle physics models providing thermal dark matter candidates that can be used as target benchmarks in future search campaigns. This constitutes a golden opportunity for CTA to either discover or rule out multi-TeV thermal dark matter in a corner of parameter space where all other experimental efforts are basically insensitive.
The international political economy of economic integration and conflict How international integration deters bilateral conflict

----------Abstract: This paper combines the economics conflict deterrence literature with the robust literature on economic integration agreements, connecting the once separate fields. The paper uses the gravity model on a panel data set containing all of the bilateral country pairs in the world between 1976 and 2010, and finds evidence in favour of the capitalist peace theory hypothesis that increased trade and integration decrease conflict between trading partners. The paper constructs three additional informal integration action variables capturing monetary integration (exchange rate correlation), economic integration (consumption correlation), and political integration (UN voting similarity) to supplement the formal economic integration agreement variable. It finds that higher levels of formal economic integration agreements and informal integration actions decrease both the level and the probability of international conflict between bilateral country pairs.
Physical properties underlying observed kinematics of satellite galaxies

We study the kinematics of satellites around isolated galaxies selected from the Sloan Digital Sky Survey (SDSS) spectroscopic catalog. Using a model of the phase-space density previously measured for the halos ofCDM dark matter cosmological sim- ulations, we determine the properties of the halo mass distribution and the orbital anisotropy of the satellites as a function of the colour-based morphological type and the stellar mass of the central host galaxy. We place constraints on the halo mass and the concentration parameter of dark matter and the satellite number density profiles. We obtain a concentration-mass relation for galactic dark matter haloes that is consis- tent with predictions of a standardCDM cosmological model. At given halo or stellar mass, red galaxies have more concentrated halos than their blue counterparts. The frac- tion of dark matter within a few effective radii is minimal for 11.25 < logM⋆ < 11.5. The number density profile of the satellites appears to be shallower than of dark mat- ter, with the scale radius typically 60 per cent larger than of dark matter. The orbital anisotropy around red hosts exhibits a mild excess of radial motions, in agreement with the typical anisotropy profiles found in cosmological simulations, whereas blue galaxies are found to be consistent with an isotropic velocity distribution. Our new constraints on the halo masses of galaxies are used to provide analytic approximations of the halo-to-stellar mass relation for red and blue galaxies.