Miracle-dz/UniFAR-FTUs huggingface dataset:
Tunable dual-species Bose-Einstein condensates of 39K and 87Rb

We present the production of dual-species Bose-Einstein condensates of K and Rb. Preparation of both species in the |F = 1,mF = −1〉 state enabled us to exploit a total of three Feshbach resonances which allows for simultaneous Feshbach tuning of the K intraspecies and the K-Rb interspecies scattering length. Thus dual-species Bose-Einstein condensates were produced by sympathetic cooling of K with Rb. A dark spontaneous force optical trap was used for Rb, to reduce the losses in K due to light-assisted collisions in the optical trapping phase, which can be of benefit for other dual-species experiments. The tunability of the scattering length was used to perform precision spectroscopy of the interspecies Feshbach resonance located at 117.56(2) G and to determine the width of the resonance to 1.21(5) G by rethermalization measurements. The transition region from miscible to immiscible dual-species condensates was investigated and the interspecies background scattering length was determined to 28.5 a0 using an empirical model. This paves the way for dual-species experiments with K and Rb BECs ranging from molecular physics to precision metrology.
A minimal substorm model that explains the observed statistical distribution of times between substorms

A minimal model for the evolution of the global dynamical state of the magnetotail during the substorm has been developed, involving only three simple rules and one free parameter D – the period between substorms under constant solar wind driving. The model is driven with a power input derived from solar wind observations from the Wind spacecraft between 1995 and 1998, to derive a sequence of simulated substorm onsets. For values of D between 2.6 h and 2.9 h, the probability distribution of waiting times between successive simulated substorm onsets is not significantly different to an empirical distribution derived from energetic particle observations at geostationary orbit in 1982‐3. Similar results are obtained using solar wind data from the ACE spacecraft between 1998 and 2002. Thus, we argue that the minimal substorm model provides a useful statistical and physical description of the timing of substorm onsets and possibly other substorm properties.
Gate-modulated weak anti-localization and carrier trapping in individual Bi2Se3 nanoribbons

We report a gate-voltage modulation on the weak anti-localization of individual topological insulator Bi2Se3 nanoribbons. The phase coherence length decreases with decreasing the carrier density of the surface states on the bottom surface of the Bi2Se3 nanoribbon as tuning the gate voltage from 0 to −100 V, indicating that the electron-electron interaction dominates the decoherence at low carrier density. Furthermore, we observe an abnormal conductance decline at positive gate voltage regime, which is ascribed to the capture of surface carriers by the trapping centers in the surface oxidation layer.
Molecular dynamics simulation of shock melting of aluminum single crystal

Molecular dynamics method in conjunction with multi-scale shock technique is employed to study the melting characteristics of aluminum single crystal under dynamic conditions. The simulated results show that a linear relationship exists between the shock wave velocity and particle velocity, in good agreement with the experimental data. Comparing the Lindemann melting curve with the two Hugoniot curves for the solid and liquid phases, the Hugoniot melting is found to begin at 93.6 GPa and end at 140 GPa, which is consistent with the theoretical calculations. The impact of crystal defects on the melting characteristics of aluminum single crystal is also studied, and the results indicate that the pressure and temperature increase slightly for the system experiencing the same dynamic loading due to the crystal defects.
Intervening Against Online Hate Speech: A Case for Automated Counterspeech

Online hate speech is a pressing issue that causes great harm to its targets and societal discourse as a whole. Deletion-based approaches commonly used to combat hate speech suffer from practical and ethical issues. In this brief, we discuss the use of automated counterspeech as a supplement to deletion that could address some of those issues. Empirical evidence and psychological theory point toward the potential of automated counterspeech for bystander mobilization against online hate speech and for the general improvement of online discourse. However, the application and the research of automated counterspeech are associated with unique ethical issues. Thus, we propose that automated counterspeech can serve as a valuable supplement to deletion-based approaches to combat online hate speech if it is guided by psychological theory and evaluation, as well as ethical considerations.
Calibrated Short-Range Ensemble Precipitation Forecasts Using Extended Logistic Regression with Interaction Terms

AbstractExtended logistic regression has been shown to be a method well suited to calibrating precipitation forecasts from medium-range ensemble prediction systems. The extension of the logistic regression unifies the separate predictive equations for each threshold, introducing the predictive threshold as part of the predictors. Mutually consistent probabilities and a reduction in the total number of regression parameters to be evaluated are part of the benefits of the extended approach. However, considering the predictive threshold as the only “unification” predictor constrains the regression parameters associated with the primary predictors to be constant with the threshold. To alleviate the rigidity of the extended scheme, interaction terms are introduced in the unified predictive equation. Within the framework of the convection-permitting German-focused Consortium for Small-Scale Modeling ensemble prediction system (COSMO-DE-EPS), it is shown that extended logistic regression, applied to short-range .
First-principles calculations of the band gap and optical properties of germanium sulfide

There are controversial results among the available experimental data of the germanium sulfide band gap, as well as between these results and the theoretical model-based band calculations published to date. To elucidate this situation, we performed an ab initio calculation of its electronic structure adopting the local density and generalized gradient approximations for the exchange-correlation potential. In addition, these calculations were carried out with and without the inclusion of the spin-orbit interaction. The main difference between our calculations and previous experimental and theoretical results is that we found several critical points in the valence and conduction bands that compete in defining the gap. This explains the diversity of the existent experimental results, which is also a consequence of the strong crystal anisotropy. Also, we suggest the important role of the $s\text{\ensuremath{-}}\mathrm{Ge}$ states contribution at the edge of the valence band. Based on our electronic structure, we discuss the experimental core spectra and optical properties of germanium sulfide. We found an excellent agreement between our results and the available experimental core spectra data. Furthermore, our calculated optical functions of $\mathrm{GeS}$ were satisfactorily compared against existing experimental data and they explain the origin of the optical transitions.
Uniqueness of backward asymptotically almost periodic-in-time solutions to Navier-Stokes equations in unbounded domains

We present a uniqueness theorem for backward asymptotically almost periodic solutions to the Navier-Stokes equations in $3$-dimensional unbounded domains. Thus far, uniqueness of such solutions to the Navier-Stokes equations in unbounded domain, roughly speaking, is known only for a small solution in $BC(-\infty,T;L^{3}_w)$ within the class of solutions which have sufficiently small $L^{\infty}( L^{3}_w)$-norm. In this paper, we show that a small backward asymptotically almost periodic solution in $BC(-\infty,T;L^{3}_w\cap L^{6,2})$ is unique within the class of all backward asymptotically almost periodic solutions in $BC(-\infty,T;L^{3}_w\cap L^{6,2})$.
Photovoltaic measurement of the built-in potential in organic light emitting diodes and photodiodes

We measure the voltage at which the current under illumination in poly[2-methoxy, 5-(2-ethylhexoxy)-1,4-phenylene vinylene] based light emitting diodes is equal to the dark current. At low temperatures, this voltage, which we term the “compensation” voltage, is found to be equal to the built-in potential, as measured with electroabsorption on the same diode. Diffusion of thermally injected charges at room temperature, however, shifts the compensation voltage to lower values. A model explaining this behavior is developed and its implications for the operation of organic light emitting diodes and photovoltaic cells are briefly discussed.
Sensitivity of the East Asian Summer Monsoon Circulation and Precipitation to an Idealized Large-Scale Urban Expansion

2012) Abstract A numerical simulation was performed here using a regional climate model ( RegCM3 ) at 60-km horizontal resolution to estimate the maximum impact of urbanization in East Asia on the summer monsoon precipitation in China. A new bulk urban parameterization was added into the land-surface scheme to capture the thermal, dynamic, and hydraulic effects of urban land cover. The 9-year simulation results showed that the large-scale change from natural-surface to high-density urban land cover induced an enhancement in the southwesterly wind speed in the early monsoon season across eastern China. In July and August, the enhanced southwesterlies moved to northern China, while a weakened southwesterly wind speed appeared south of the Yangtze River valley ( YRV ) . Meanwhile, a large reduction in rainfall occurred in southern China with most reduction accounted for by convective precipitation reduction. This corresponded to the reduced water-vapor supply from the weakened southwesterlies in southern China, decreased convergence in the YRV, reduced convective instability in the lower troposphere, and lessened evapotranspiration from the impervious urban surface. Accompanied by the increased southwesterlies in the west and northwest of the urban region, a moderate increase in rainfall occurred in northern China. The changes in southwesterly wind speed and rainfall in southern China were more evident in the weak East Asian summer monsoon ( EASM ) years than in the strong ones. This underlines the impact of change in large-scale intensive urban land use on regional climate in the weak phase of the EASM. As fractional urban land cover was reduced, the changes in wind and precipitation were still shown but the spatial coverage and magnitude of these changes were
The Saw-Toothed Behavior of Power Versus Sample Size and Software Solutions

With the speed of modern computers it is now feasible to replace normal approximations with exact methods. For continuous random variables it is intuitively clear that for a given significance level and alternative hypothesis the power function increases monotonically as the sample size increases. One would expect the same to be true for discrete random variables, but such is not the case. This article demonstrates in the simple case of a test of a single binomial proportion compared to a hypothesized standard that the power function has a saw-toothed shape and hence is not monotonically increasing. We demonstrate this using the software package nQuery Advisor 4.0, the version that has the capability of doing power calculations using exact binomial methods. We compare that software with competitors that also do exact binomial calculations. The reason for this counter-intuitive result is that a significance level of 0.05, for example, cannot be obtained exactly for most sample sizes. So by a 0.05 significance level for a given sample size n we mean the largest level below 0.05. That level determines the critical value for the test statistic and the critical value determines the power at any given alternative. If n is such that the exact significance level is appreciably lower than 0.05 (say 0.01) and the power is 80% at a particular alternative, the power could easily drop below 80% for n + 1 and the same alternative hypothesis, since the exact significance level does not remain at 0.01 but may stay below but get closer to 0.05. This is particularly the case for small n. We find this result to be important in determining sample size for our clinical trials. We often have endpoints that are proportions and we use fixed sample size trials to compare our device's performance to a control or an objective performance criterion. We illustrate this result in the case of a single binomial proportion, but this property really depends only on the discrete nature of the sampling distribution for the test statistic. Hence it also occurs for permutation tests and in the comparison of the difference or ratio of two binomials.
Spectra and pulse period of the binary X-ray pulsar 4U 1538-52

The 530 s binary X-ray pulsar 4U 1538-52 was observed from the X-ray astronomy satellite Tenma in 1983 June-July. An improved orbital ephemeris was derived. Also, high-quality X-ray spectra were obtained by taking into account the contribution of the Galactic ridge emission. It was found that the iron K-line emission from this source is weak, contrary to previous reports. The observed pulsation period, about 529.8 s, is about 0.4 s longer than that measured in 1976-1977, implying an average spin-down rate of 3.8 x 10 to the -9th s/s. In addition, there is some evidence for a much larger rate of instantaneous period increase. These results suggest that 4U 1538-52 is a wind-fed pulsar, and its pulsation period changes in a random-walk manner in response to fluctuations in the external torque. This is very similar to the case of Vela X-1. 46 references.
The Influence of the Andes Cordillera on Transient Disturbances

Abstract The influence of the Andes Cordillera on transient disturbances is investigated in this study using a lag-correlation analysis. This analysis shows that the unfiltered geopotential height data have a wavelike pattern moving to the east while tilting to the west in the vertical. When the wave approaches the Andes Cordillera, it exhibits orographic effects such as anticyclonic turning of a low-level disturbance trajectory, a zonal trajectory in the upper levels, distortions of the isolines of correlation, and an elongation of maximum correlation on the lee side of the Andes. The anticyclonic turning of the trajectory in the low-attitude levels and a zonal trajectory in upper levels implies a decrease in the vertical tilt of the system on the windward side and an increase in the tilt on the lee side. The increase of baroclinicity on the lee side results in baroclinic development as predicted from a linearly obtained normal-mode solution in the presence of mountains. A cross-correlation analysis of t.
Self-trapping of helium in metals

Atomistic calculations are presented which demonstrate that helium atoms in a metal lattice are able to cluster with each other, producing vacancies and nearby self-interstitial defects. Even a small number of helium atoms is found to be sufficient to create these large distortions. As few as five interstitial helium can spontaneously produce a lattice vacancy and nearby self-interstitial. An eight-helium-atom cluster gives rise to two such defects, and 16 helium atoms to more than five self-interstitial vacancy pairs. It was noted that the self-interstitials prefer to agglomerate on the same ''side'' of the helium cluster rather than to spread themselves out uniformly. The binding energy of each additional helium atom to these clusters increases with helium concentration and the trap is apparently unsaturable. A rate theory using these atomistic binding energies has been used to calculate the kinetics of helium-bubble nucleation and growth. The results are consistent with measurements of the properties of helium resulting from tritium decay.
The Common Cause Principle. Explanation via Screening off.

My Ph.D. dissertation written under the supervision of Prof. Tomasz Placek at the Institute of Philosophy of the Jagiellonian University in Krakow. In one of its most basic and informal shapes, the principle of the common cause states that any surprising correlation between two factors which are believed not to directly influence one another is due to their (possibly hidden) common cause. Here we will be concerned with a version od this idea which possesses a purely probabilistic formulation. It was introduced, in the form of a general principle, by Hans Reichenbach in his posthumously published book "The Direction of Time". The central notion of the principle in Reichenbach's formulation, and of the current essay, is that of screening off: two correlated events are screened off by a third event if conditioning on the third event makes them probabilistically independent. Reichenbach's principle marks also the beginning of a new field of philosophy: namely, that of ``probabilistic causality''. For the most part, the current essay can be seen as an effort at checking how far one can go with the purely statistical notions revolving around Reichenbach's idea of common cause. In short, the answer is ``surprisingly far''; in some classes of probability spaces all correlations between ``interesting'' (e.g. ``logically independent'', this will be formally defined in chapter 6) events possess explanations of such sort. However, this fact lends itself to opposing interpretations; more on that in the conclusion. Chapters 6 and 7 contain mathematical results concerning these issues. The screening-off condition requires an equality of a probabilistic nature to hold; chapter 8 is a short discussion of slightly weakened versions of the condition, which hold if the sides of the above mentioned equality differ to a small degree. In chapter 2, after some mathematical preliminaries, we study the various formulations of the principle which might be said to stem from the original idea of Reichenbach. We also examine a few of the most salient counterarguments, which undermine at least some of the formulations. Chapter 3 is of a formal nature, dealing with various probabilistic notions which can be thought of as generalizations of Reichenbach's concept of common cause. The next chapter concerns the relationship between the idea of common causal explanation and the Bell inequalities. In chapter 5 we briefly present the form of Reichenbach's principle which can be found in the field of representing causal structures by means of directed acyclic graphs.
Growth and properties of KLu(WO4)2, and novel ytterbium and thulium lasers based on this monoclinic crystalline host

High‐quality crystals of monoclinic KLu(WO4)2, shortly KLuW, were grown with sizes sufficient for its characterization and substantial progress was achieved in the field of spectroscopy and laser operation with Yb3+‐ and Tm3+‐doping. We review the growth methodology for bulk KLuW and epitaxial layers, its structural, thermo‐mechanical, and optical properties, the Yb3+ and Tm3+ spectroscopy, and present laser results obtained in several operational regimes both with Ti:sapphire and direct diode laser pumping using InGaAs and AlGaAs diodes near 980 and 800 nm, respectively. The slope efficiencies with respect to the absorbed pump power achieved with continuous‐wave (CW) bulk and epitaxial Yb:KLuW lasers under Ti:sapphire laser pumping were ≈ 57 and ≈ 66%, respectively. Output powers as high as 3.28 W were obtained with diode pumping in a simple two‐mirror cavity where the slope efficiency with respect to the incident pump power reached ≈ 78%. Passively Q‐switched laser operation of bulk Yb:KLuW was realized with a Cr:YAG saturable absorber resulting in oscillation at ≈ 1031 nm with a repetition rate of 28 kHz and simultaneous Raman conversion to ≈ 1138 nm with maximum energies of 32.4 and 14.4 μJ, respectively. The corresponding pulse durations were 1.41 and 0.71 ns. Passive mode‐locking by a semiconductor saturable absorber mirror (SESAM) produced bandwidth‐limited pulses with duration of 81 fs (1046 nm, 95 MHz) and 114 fs (1030 nm, 101 MHz) for bulk and epitaxial Yb:KLuW lasers, respectively. Slope efficiency as high as 69% with respect to the absorbed power and an output power of 4 W at 1950 nm were achieved with a diode‐pumped Tm:KLuW laser. The slope efficiency reached with an epitaxial Tm:KLuW laser under Ti:sapphire laser pumping was 64 %. The tunability achieved with bulk and epitaxial Tm:KLuW lasers extended from 1800 to 1987 nm and from 1894 to 2039 nm, respectively.
Numerical Investigation of Energy Extraction in a Tandem Flapping Wing Configuration

A number of flying insects make use of tandem-wing configurations, suggesting that such a setup may have potential advantages over a single wing at low Reynolds numbers. Dragonflies, which are fast and highly maneuverable, demonstrate well the potential performance of such a design. In this paper, a tandem-wing flapping configuration is simulated at a Reynolds number of 10,000 using an incompressible Navier–Stokes solver and an overlapping gridmethod. The flappingmotion consists of a simple sinusoidal pitch and plungemotionwith a spacing of one chord length between both wings. The arrangement was tested at a Strouhal number of 0.3 for three different phase angles: 0, 90, and 180 deg. The aerodynamics of the hindwing was compared in detail to a single wing, with the same geometry and undergoing the same flapping kinematics, to determine the effect of vortex shedding from the forewing on the hindwing, as well as how the phase angle affects the interaction. The average lift, thrust, and power coefficients and the average efficiency of the foreand hindwings were comparedwith a single wing to determine how the tandem-wing interaction affects performance. The results show that adjusting the phase angle allows the tandem wing to change the flight mode. At 0 deg phase lag, the tandem wing produces high thrust at high propulsive efficiency, but low lift efficiency. Switching to 90=180 deg phase lag decreases the thrust production and propulsive efficiency but greatly increases the lift efficiency. At 90=180 deg, the power coefficient is much lower than at 0 deg, due to the hindwing extracting energy from the wake of the forewing.
Geodesic structure of the Born-Infeld black hole

In this paper we study the trajectories of test particles in a geometry that is the nonlinear electromagnetic generalization of the Reissner–Nordstrom black hole. The solution was originally derived by Garcia, Salazar and Plebanski (1984 Nuovo Cimento 84 65–90). The studied spacetime is an Einstein–Born–Infeld solution, nonsingular outside a regular event horizon and characterized by three parameters: mass M, charge Q and the Born–Infeld parameter b related to the magnitude of the electric field at the origin. Asymptotically it is a Reissner–Nordstrom solution.
Radiative forcing of simulated tropical cloud clusters

Abstract A number of field experiments and subsequent studies in the 1970s and 1980s have led to the belief that radiative processes play a more significant role in the evolution of tropical mesoscale convective systems (MCSS) than was once thought. In this study, an interactive radiative transfer scheme is incorporated into a two-dimensional version of the Pennsylvania State University-NCAR Mesoscale Model to simulate the evolution of these systems within a large-scale environment under a diurnally varying radiative influence. The radiative effects are examined in terms of the net rainfall, diurnal phasing, and the vertical distribution of diabatic heating within the systems. In addition, three current radiative forcing hypotheses are addressed. Simulations of individual MCSs with radiation produced more rainfall than those without it. While runs with forced background meant all peaked after the same elapsed time regardless of diurnal initialization time, the peak rainfall rates that occurred at night we.