Miracle-dz/UniFAR-FTUs huggingface dataset:
On the Sensations of Tone as a Physiological Basis for the Theory of Music

IN the general advance of scientific knowledge which has taken place during the last half-century, the science of acoustics has hardly received its fair share of attention. Founded on principles originated by the ancients, and afterwards extended by Galileo, Newton, Taylor, Sauveur, Bernouilli, Euler, Smith, Young, and others, the first great and complete work on it was “Die Akustik,” of Chladni, published in Germany in 1802, but which is chiefly known by its French translation.On the Sensations of Tone as a Physiological Basis for the Theory of Music.By Hermann F. Helmholtz Translated with the author's sanction by Alex. J. Ellis, F.R. S. , &c. (London: Longmans and Co., 1875)
Impact of cosmological satellites on stellar discs: dissecting one satelliteat a time

Within the standard hierarchical structure formation scenario, Milky Way-mass dark matter haloes have hundreds of dark matter subhaloes with mass $\gtrsim 10^8 \, {\rm M_{\odot}}$. Over the lifetime of a galactic disc a fraction of these may pass close to the central region and interact with the disc. We extract the properties of subhaloes, such as their mass and trajectories, from a realistic cosmological simulation to study their potential effect on stellar discs. We find that massive subhalo impacts can generate disc heating, rings, bars, warps, lopsidedness as wells as spiral structures in the disc. Specifically, strong counter-rotating single-armed spiral structures form each time a massive subhalo passes through the disc. Such single-armed spirals wind up relatively quickly (over $1-2$ Gyrs) and are generally followed by co-rotating two-armed spiral structures that both develop and wind up more slowly. In our simulations self-gravity in the disc is not very strong and these spiral structures are found to be kinematic density waves. We demonstrate that there is a clear link between each spiral mode in the disc and a given subhalo that caused it, and by changing the mass of the subhalo we can modulate the strength of the spirals. Furthermore, we find that the majority of subhaloes interact with the disc impulsively, such that the strength of spirals generated by subhaloes is proportional to the total torque they exert. We conclude that only a handful of encounters with massive subhaloes is sufficient for re-generating and sustaining spiral structures in discs over their entire lifetime.
Covariance structure models and influence diagrams

Statisticians use covariance structure modeling as a versatile tool for modeling and testing theory. The models that result provide explicit and detailed descriptions of stochastic systems. We show how covariance structure models are related—mathematically, conceptually, philosophically and practically—to Gaussian influence diagrams as described by Shachter and Kenley (1989). This relationship suggests ways in which covariance structure modeling can be used to advantage in the prescriptive domain of decision analysis. The paper includes an example concerning the management of hazardous materials, in which a covariance structure model is converted to an influence diagram for use in a prescriptive analysis.
Statistical mechanics based model for negative bias temperature instability induced degradation

A physics based model for negative bias temperature instability (NBTI) induced degradation is proposed. Like previous models, this model attributes NBTI to depassivation of Si–H bonds at the SiO2∕Si interface. The two distinguishing features of the proposed model are: (i) statistical mechanics is applied to calculate the decrease in interfacial Si–H density as a function of stressing conditions, and (ii) hydrogen diffusion in the oxide is assumed to be dispersive and the diffusing species is identified with the positively charged hydrogen ion (Hi+). The model assumes that as Hi+ diffuses away from the interface into the oxide, interfacial and bulk traps are created. Based on these model assumptions, an equation for the threshold voltage shift (ΔVt) is derived as a function of stressing time, oxide field, temperature, oxide thickness, and initial Si–H density at the interface. The model predicts that ΔVt would increase with a power law dependence at earlier stressing times and would saturate at longer time.
Optimizing the Crystallinity of Heptazine-Based Crystalline Carbon Nitride by Regulating Temperature for Enhanced Photocatalytic H2 Evolution

Polymeric carbon nitride (PCN), as a metal-free photocatalyst, has drawn wide attention in the photocatalytic H2 evolution. However, the photocatalytic activity of directly synthesized PCN is limited by its low crystallinity. Currently, regulating the melon-based PCN into tri-s-triazine-based crystalline PCN to further optimize its structure has been proved to effectively improve its photocatalytic activity. The heptazine-based crystalline carbon nitride, potassium poly(heptazine imide) (abbreviated as K-PHI), has been used in photocatalytic H2 evolution benefiting from its high crystallinity, as the high crystallinity narrows the bandgap and increases the light capture efficiency and increases the charge mobility. Nevertheless, the effect of synthesis temperature on crystallinity has not yet been reported. In this work, the effect of temperature on the crystallinity of heptazine-based crystalline carbon nitride was studied by one-step synthesis at different temperatures. It shows that the heptazine-based crystalline structure appears when the temperature exceeds 540°C. Additionally, the crystallinity of all samples is gradually improved with increasing temperature until the sample begins to decompose beyond 630°C. The sample synthesized at 630°C demonstrates the highest photocatalytic H2 evolution rate of 1.798 mmol h−1 g−1 under visible light irradiation, which is 31.5 times that of bulk PCN. Based on systematic material characterizations, the mechanism of the effect of synthesis temperature on crystallinity and the contribution of crystallinity to photocatalytic efficiency were revealed.
Study Abroad Develops Cultural Intelligence for International Business Effectiveness, Special Relevance for PELL Students

The global economy and COVID created an interdependency where managers work in multiple countries, requiring cultural awareness. Cultural Intelligent (CQ) is a recent concept described as predictor of cultural adaptation. We studied 188 international business university students in terms of gender, language, major, financial need, and study abroad. We found no statistically significant gender differences in CQ, but we found differences in having a second language, level of studies, and study abroad experience. We also found PELL students develop more CQ than the rest of the students while studying abroad. This study helps to understand the key elements to develop CQ among international students to be effective in the present global business world and to promote the participation of PELL students in study abroad experiences. Abstract in SpanishLa economía global y COVID crearon una interdependencia en la que los gerentes trabajan en varios países, lo que requiere conciencia cultural. La Inteligencia Cultural (CQ) es un concepto reciente descrito como predictor de adaptación cultural. Estudiamos a 188 estudiantes universitarios de negocios internacionales en términos de género, idioma, especialización, necesidades financieras y estudios en el extranjero. No encontramos diferencias de género estadísticamente significativas en CQ, pero encontramos diferencias en tener un segundo idioma, nivel de estudios y experiencia de estudios en el extranjero. También encontramos que los estudiantes PELL desarrollan más CQ que el resto de los estudiantes mientras estudian en el extranjero. Este estudio ayuda a comprender los elementos clave para desarrollar CQ entre los estudiantes internacionales para ser efectivos en el mundo empresarial global actual y promover la participación de los estudiantes PELL en experiencias de estudio en el extranjero.
The Fall of Active Galactic Nuclei and the Rise of Star-forming Galaxies: A Close Look at the Chandra Deep Field X-Ray Number Counts

We investigate the X-ray number counts in the 1–2 Ms Chandra Deep Fields (CDFs) to determine the contributions of faint X-ray source populations to the extragalactic X-ray background (XRB). X-ray sources were separated into active galactic nuclei (AGNs), star-forming galaxies, and Galactic stars primarily on the basis of their X-ray–to–optical flux ratios, optical spectral classifications, X-ray spectra, and intrinsic X-ray luminosities. Number count slopes and normalizations below 2 × 10-15 ergs cm-2 s-1 were calculated in each band for all source types assuming a single power-law model. We find that AGNs continue to dominate the number counts in the 0.5–2.0 and 2–8 keV bands. At flux limits of ≈2.5 × 10-17 ergs cm-2 s-1 (0.5–2.0 keV) and ≈2.0 × 10-16 ergs cm-2 s-1 (2–8 keV), the overall AGN source densities are 7166 and 4558 sources deg-2, respectively; these are factors of ∼10–20 higher than those found in the deepest optical spectroscopic surveys. Although still a minority, the number counts of star-forming galaxies climb steeply, such that they eventually achieve source densities of 1727 sources deg-2 (0.5–2.0 keV) and 711 sources deg-2 (2–8 keV) at the CDF flux limits. The number of star-forming galaxies will likely overtake the number of AGNs at ∼1 × 10-17 ergs cm-2 s-1 (0.5–2.0 keV) and dominate the overall number counts thereafter. Adopting XRB flux densities of (7.52 ± 0.35) × 10-12 ergs cm-2 s-1 deg-2 for 0.5–2.0 keV and (1.79 ± 0.11) × 10-11 ergs cm-2 s-1 deg-2 for 2–8 keV, the CDFs resolve a total of 89.5 percent and 92.6 percent of the extragalactic 0.5–2.0 and 2–8 keV XRBs, respectively. AGNs as a whole contribute ≈83% and ≈95% to these resolved XRB fractions, respectively, whereas star-forming galaxies comprise only ≈3% and ≈2%, respectively, and Galactic stars comprise the remainder. Extrapolation of the number count slopes can easily account for the entire 0.5–2.0 and 2–8 keV XRBs to within statistical errors. We also examine the X-ray number counts as functions of intrinsic X-ray luminosity and absorption, finding that sources with L0.5–8 keV > 1043.5 ergs s-1 and NH < 1022 cm-2 are the dominant contributors to the 0.5–2.0 keV XRB flux density, whereas sources with L0.5–8 keV = 1042.5–1044.5 ergs s-1 and a broad range of absorption column densities primarily contribute to the 2–8 keV XRB flux density. This trend suggests that even less intrinsically luminous, more highly obscured AGNs may dominate the number counts at higher energies, where the XRB intensity peaks. Finally, we revisit the reported differences between the CDF-North and CDF-South number counts, finding that the two fields are consistent with each other except for sources detected at 2–8 keV below F2–8 keV ≈ 1 × 10-15 ergs cm-2 s-1, for which deviations gradually increase to ≈3.9 σ.
Two Types of Photo-Induced Voltages in Terbium Molybdate

The dependences of the photo-induced voltage in the orthorhombic ferroelectric terbium molybdate g ' m Tb 2 (MoO 4 ) 3 upon the time t of the illumination by a laser beam was measured at room temperature at 0,1 s h t h 4500 s. The power of the laser radiation was 0,4 W. The distribution of the intensity along the sample was varied from highly inhomogeneous to homogeneous. It was found that the photo-induced voltages of two types with opposite signs appear due to the inhomogeneous illumination. The model was proposed to explain the appearance of the photo-induced voltage due to the inhomogeneous illumination. Qualitative data on the relaxation of the photo-induced voltage were obtained.
A search for $B-L$ $R$-parity-violating top squarks in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS experiment

A search is presented for the direct pair production of the stop, the supersymmetric partner of the top quark, that decays through an R-parity-violating coupling to a final state with two leptons and two jets, at least one of which is identified as a b-jet. The dataset corresponds to an integrated luminosity of 36.1 fb−1 of proton–proton collisions at a center-of-mass energy of √ s = 13 TeV, collected in 2015 and 2016 by the ATLAS detector at the LHC. No significant excess is observed over the Standard Model background, and exclusion limits are set on stop pair production at a 95% confidence level. Lower limits on the stop mass are set between 600 GeV and 1.5 TeV for branching ratios above 10% for decays to an electron or muon and a b-quark.
Band tail interface states and quantum capacitance in a monolayer molybdenum disulfide field-effect-transistor

Although MoS2 field-effect transistors (FETs) with high-k dielectrics are promising for electron device applications, the underlying physical origin of interface degradation remains largely unexplored. Here, we present a systematic analysis of the energy distribution of the interface state density (Dit) and the quantum capacitance (CQ) in a dual-gate monolayer exfoliated MoS2 FET. The CQ analysis enabled us to construct a Dit extraction method as a function of EF. A band tail distribution of Dit with the lowest value of 8 × 1011 cm−2 eV−1 suggests that Dit is not directly related to the sharp peak energy distribution of the S vacancy. Therefore, the Mo–S bond bending related to the strain at the interface or the surface roughness of the SiO2/Si substrate might be the origin. It is also shown that ultra-thin 2D materials are more sensitive to interface disorder due to the reduced density of states. Since all the constituents for the measured capacitance are well understood, I–V characteristics can be reproduced by utilizing the drift current model. As a result, one of the physical origins of the metal/insulator transition is suggested to be the external outcome of interface traps and quantum capacitance.
Observations of the X-Ray Nova GRO J0422+32. II. Optical Spectra Approaching Quiescence

We present results obtained from a series of 5~\AA\ resolution spectra of the X-ray Nova GRO~J0422+32 obtained in 1993~October, when the system was approximately 2 magnitudes above quiescence, with ${\rm R \sim 19}$. The data were obtained in an effort to measure the orbital radial velocity curve of the secondary, but detection of the narrow photospheric absorption lines needed to do this proved elusive. Instead we found wide absorption bands reminiscent of M~star photospheric features. The parameters determined by fitting accretion disk line profiles (Smak profiles) to the H$\alpha$ line are similar to those found in several strong black-hole candidates. Measurements of the velocity of the H$\alpha$ line are consistent with an orbital period of 5.1~hours and a velocity semi-amplitude of the primary of $34 \pm 6$~\kms. These measurements, when combined with measurements of the velocity semi-amplitude of the secondary made by others, indicate that the mass ratio $q \sim 0.09$. If the secondary follows the empirical mass-radius relation found for CVs, the low $q$ implies a primary mass of $M_x \sim 5.6$\mo, and a rather low (face-on) inclination. The H$\alpha$ EW is found to be modulated on the orbital period with a phasing that implies a partial eclipse of the disk by the secondary, but simultaneous R~band photometry shows no evidence for such an eclipse.
A New Symmetric Modified Wilkinson Power Divider Using L-Type Dual-Band Impedance Matching Structure

Based on L-type dual-band impedance matching structure, this paper presents a new symmetric modified Wilkinson power divider for dual-band applications. In the matching structure, two transmission line stubs can be used to implement impedance matching and space isolation for two transmission ways, simultaneously. In the isolation structure, a single resistor is applied, and the design values are adjusted according to the center frequency ratio. In this proposed power divider, the ideal matching of all ports, equal power splitting and isolation between the output ports can be achieved. Theoretically, the nonlinear design equations for normalized parameters are directly derived based on the conventional even- and odd-mode analysis. In microstrip experiments, simulated and measured results of two fabricated power dividers with different frequency ratios are given. It can be clearly seen that there are good agreements between the theoretical and experimental results.
Yield strength of tantalum for shockless compression to 18 GPa

A magnetic loading technique was used to study the strength of pure, annealed, and cold-rolled polycrystalline tantalum under planar ramp loading at strain rates of ∼106/s. Both the initial yield strength and the flow strength after compression to peak loading stresses of 18 GPa were determined. For sample thicknesses ranging from 0.5–6.0 mm, it was found that the elastic limit of ∼3.2 GPa, corresponding to a yield strength of 1.6 GPa, for annealed Ta was sharply defined and essentially independent of sample thickness. After elastic yielding, relaxation of the longitudinal stress occurred for sample thicknesses greater than ∼0.5 mm, approaching an asymptotic value of ∼1.6 GPa. Two different purities of annealed Ta showed no difference in initial yield strength. Cold-rolling annealed Ta to 26% plastic strain resulted in a more dispersed elastic precursor with an amplitude of about 1.6 GPa and with no stress relaxation after yielding. Analysis of unloading wave profiles from the peak loading states allowed .
Electron-phonon interaction in the solid form of the smallest fullerene C20

The electron-phonon coupling of a theoretically devised carbon phase made by assembling the smallest fullerenes C20 is calculated from first principles. The structure consists of C20 cages in a fcc lattice interlinked by two bridging carbon atoms in the interstitial tetrahedral sites (fcc-C22). The crystal is insulating but can be made metallic by doping with interstitial alkali atoms. In the compound NaC22 the calculated coupling constant λ/N(0) is 0.28 eV, a value much larger than in C60, as expected from the larger curvature of C20. On the basis of McMillan's formula, the calculated λ = 1.12 and a μ* assumed in the range 0.3–0.1, a superconducting Tc in the range 15–55 K is predicted.
Gravitational collapse to a Kerr–Newman black hole

We present the first systematic study of the gravitational collapse of rotating and magnetised neutron stars to charged and rotating (Kerr-Newman) black holes. In particular, we consider the collapse of magnetised and rotating neutron stars assuming that no pair-creation takes place and that the charge density in the magnetosphere is so low that the stellar exterior can be described as an electrovacuum. Under these assumptions, which are rather reasonable for a pulsar that has crossed the 'death line', we show that when the star is rotating, it acquires a net initial electrical charge, which is then trapped inside the apparent horizon of the newly formed back hole. We analyse a number of different quantities to validate that the black hole produced is indeed a Kerr-Newman one and show that, in the absence of rotation or magnetic field, the end result of the collapse is a Schwarzschild or Kerr black hole, respectively.
New Analytical Formulae for Supercritical Accretion Flows

We examine a new family of global analytic solutions for optically thick accretion disks, which includes the supercritical accretion regime. We found that the ratio of the advection cooling rate, Qadv, to the viscous heating rate, Qvis, i.e., f = Qadv/Qvis, can be represented by an analytical form dependent on the radius and the mass accretion rate. The new analytic solutions can be characterized by the photon-trapping radius, rtrap, inside which the accretion time is less than the photon diffusion time in the vertical direction; the nature of the solutions changes significantly as this radius is crossed. Inside the trapping radius, f approaches f ∝ r0, which corresponds to the advection-dominated limit (f ~ 1), whereas outside the trapping radius, the radial dependence of f changes to f ∝ r-2, which corresponds to the radiative-cooling-dominated limit. The analytical formula for f derived here smoothly connects these two regimes. The set of new analytic solutions reproduces well the global disk structure obtained by numerical integration over a wide range of mass accretion rates, including the supercritical accretion regime. In particular, the effective temperature profiles for our new solutions are in good agreement with those obtained from numerical solutions. Therefore, the new solutions will provide a useful tool not only for evaluating the observational properties of accretion flows, but also for investigating the mass evolution of black holes in the presence of supercritical accretion flows.
Quality Assessment of Sub-base Highway Pavement Materials in Lagelu Local Government Area, Ibadan, Oyo State, Nigeria

Road development quality delivery in West Africa mostly depends on the quality of available sub-base pavement materials within economic distance. This paper thus aimed at assessing the quality of sub-base road pavement material in Lagelu Local Government Area of Ibadan, South-Western, Nigeria. Soil samples were collected from four different locations at depths ranging from 0.5m to 1.0m. Samples were subjected to Natural moisture content, Specific gravity, Grain size analysis, Atterberg limits, Compaction and California bearing ratio laboratory tests. The sieve analysis results indicate that the fine grain content varying from 16.80 % and 30.70 %. The soil samples are well graded ranging from coarse to clay particle sizes. The compaction test results revealed the maximum dry density range from 2.25 Mg/m3 to 2.28 Mg/m3 and optimum moisture content of between 7.1 % and 7.3 %. The materials were classified after AASHTO soil classification system as A-1-b with California Bearing Ratio (CBR) test results ranging from 74% to 76%. The variation in the values depends on the moisture content and the density of the materials. It was observed that the values were well within the permissible specification by the Federal Ministry of Works General Specifications of the country, rated as excellent to good sub-base materials.
Spatial Distribution, Seasonal Abundance and Physio-Chemical Assessment of Mosquito Larval Breeding Sites in Mardan District, Khyber Pakhtunkhwa, Pakistan

Background: Mosquitoes (Diptera: Culicidae) are haemotophagus insects and are vectors of many arthropod-borne diseases. Present study aimed to explore species composition, seasonal abundance, spatial distribution and physio-chemical properties of larval breeding sites of mosquitoes in District Mardan, Khyber Pakhtunkhwa, Pakistan. Methods: Both adults and larvae of mosquitoes were collected through light traps, insecticide spray, mouth aspirator and larval standard dipping method in District Mardan from May to November 2017. Water samples from larval sites were physio-chemically analysed. Results: 5078 (3704 adults and 1374 larvae) mosquito specimens were collected in Mardan, Katlang and Takhtbhai tehsils. Six species in four genera were reported. Culex pipiens (89.80%) and Armigeres subalbatus (9.20%) were the most abundant species. Diversity was high in Takhtbhai (0.29) followed by Katlang (0.28) and Mardan (0.25). Greater number of specimens were recorded in peridomestic sites (93.97%) as compared to domestic habitats (6.03%). Culex pipiens larval abundance had negative correlation with pH whereas it correlated positively with electric conductivity, salinity, and TDS (total dissolved sulphur). Mosquito abundance peaked in August and July while the lowest was in May. Their monthly abundance had positive correlation with rainfall (r= 0.5069), relative humidity (r= 0.4439) and mean minimum temperature (r= 0.2866). Number of mosquitoes was highest at low elevation < 347m asl (above sea level) in agriculture land and near to water bodies (streams). Conclusion: Culex pipiens being the most abundant species, was susceptible to high pH. Mosquitoes preferred habitats were at low elevation in agriculture land.