Miracle-dz/UniFAR-FTUs huggingface dataset:
The role of the information set for forecasting—with applications to risk management

Predictions are issued on the basis of certain information. If the forecasting mechanisms are correctly specified, a larger amount of available information should lead to better forecasts. For point forecasts, we show how the effect of increasing the information set can be quantified by using strictly consistent scoring functions, where it results in smaller average scores. Further, we show that the classical Diebold-Mariano test, based on strictly consistent scoring functions and asymptotically ideal forecasts, is a consistent test for the effect of an increase in a sequence of information sets on $h$-step point forecasts. For the value at risk (VaR), we show that the average score, which corresponds to the average quantile risk, directly relates to the expected shortfall. Thus, increasing the information set will result in VaR forecasts which lead on average to smaller expected shortfalls. We illustrate our results in simulations and applications to stock returns for unconditional versus conditional risk management as well as univariate modeling of portfolio returns versus multivariate modeling of individual risk factors. The role of the information set for evaluating probabilistic forecasts by using strictly proper scoring rules is also discussed.
Estimating the Correlation Dimension of Atmospheric Time Series

Abstract The correlation dimension D is commonly used to quantify the chaotic structure of atmospheric time series. The standard algorithm for estimating the value of D is based on finding the slope of the curve obtained by plotting ln C(r) versus ln r, where C(r) is the correlation integral and r is the distance between points on the attractor. An alternative, probabilistic method proposed by Takens is extended and tested here. This method is based on finding the sample means of the random variable (r/ρ)p[ln(r/ρ)]k, expressed as the conditional expected value E((r/ρ)p[ln(r/ρ)]k : r < ρ), for p and k nonnegative numbers. The sensitivity of the slope method and of the extended estimators Dpk(ρ) for approximating D is studied in detail for three ad hoc correlation integrals and for integer values of p and k. The first two integrals represent the effects of noise or undersampling at small distances and the third captures periodic lacunarity, which occurs by definition when the ratio C(xρ)/C(ρ) fails to conve.
Evaluation of von Karman's Constant from Integral Flow Parameters

Theory and data for turbulent flow in smooth pipes are employed to evaluate von Karman’s constant from integral flow parameters. A set of equations for mean velocity and centerline velocity are derived from the equations of motion for steady, uniform turbulent flow in smooth pipes. An eddy-viscosity closure is used that has a parabolic asymptotic form near the pipe wall and decays near the pipe centerline. The velocity equations depend on von Karman’s constant k, a coefficient relating the bottom roughness parameter to the scale of the viscous sublayer β\N=(ν\N/\Iu\N*)/z\d0\N, and a coefficient in the eddy-viscosity decay term α\N. These constants are evaluated by fitting the model equations to velocity measurements from 10 high-quality data sets. A narrowly constrained value, \Ik\N=0.408±\N0.004 at 95% confidence, is obtained from mean velocity data as a function of Reynolds number. Mean velocity and centerline velocity data give α\N=3.34 and β\N=8.72 for the other two parameters. Examining the variation of \Ik\N over ranges of Reynolds number reveals that \Ik\N does not vary with Reynolds number to the accuracy of the measurements.
Neural Adaptive Loop Filtering for Video Coding: Exploring Multi-Hypothesis Sample Refinement

Adaptive loop filtering (ALF) is extensively investigated for lossy video coding to mitigate compression noise. Numerous learning-based ALFs have emerged recently and improved the coding efficiency significantly through the use of complexity-intensive, large-scale models trained on excessive samples, making it impractical for real-life applications. By contrast, lightweight, small-scale ALF models cannot promise convincing performance and model generalization. In principle, the ALF estimates the sample distortion for restoration. Instead of directly approximating the distortion as in existing solutions, we reformulate it as a Multi-hypothesis Sample Refinement (MSR) problem. To this end, we first generate multiple distortion hypotheses through a deep neural network (DNN) model. Then, these hypotheses are linearly superimposed to approximate the final distortion through the minimization of mean square error (MMSE) between the filtered reconstruction and its original, uncompressed input. Finally, the linear superimposition coefficients are explicitly signaled in the compressed bitstream. As seen, the superimposition coefficients inherently generalize the MSR to various content. And using DNNs to generate distortion hypotheses essentially models the spatial priors of a local block and its underlying compression error distribution. As a result, the MSR using a small-scale convolutional neural network (CNN) model with only 5k parameters and 5 KMACs/pixel achieves 4.35% (Intra) and 2.49% (Inter) BD-Rate (Bjøntegaard Delta Rate) gains over the AV1 anchor. Ablation studies further demonstrate that the MSR can be generalized to diverse small-scale network structures, different standards (e.g., H.265/HEVC and H.266/VVC), and diverse video content (e.g., screen videos).
Near-Term Effects of Short-Term Study Abroad: A Longitudinal Examination of Learner Perceptions

A relatively small body of research has been conducted on the near- and long-term effects of study abroad (SA) to date. This existing research suggests that SA effects on language skills tend to be volatile, while the impact on various aspects of learners’ personal, academic, and professional development may be longer-lasting. Yet, learner perspectives on the dynamics and durability of such effects, in particular in the context of short-term SA programs, remain largely unexplored. This study hence investigates the near-term impact of short-term SA programs as experienced by students within the first months and years following their sojourns. A qualitative case-study design is employed to examine the accounts of four American students of German, who studied abroad in Austria for four weeks and were interviewed repeatedly over a period of up to 40 months after their sojourns. The results suggest that, from the students’ perspective, many effects deteriorate in the near term, although the overall sojourn experience still appears influential. Abstract in German Nur wenige Forschungsvorhaben haben sich bislang den mittel- bis langfristigen Auswirkungen studentischer Auslandsaufenthalte gewidmet; die bisherige Datenlage deutet jedoch darauf hin, dass die Auswirkungen auf sprachliche Kompetenzen eher unbeständig sind, wohingegen die persönliche, studiums- und berufsbezogene Entwicklung der Lernenden länger von einem Auslandsaufenthalt beeinflusst wird. Die Dynamik und Beständigkeit derartiger Auswirkungen wurden jedoch kaum mit Blick auf kurze Auslandsaufenthalte (≤ acht Wochen) sowie aus der Perspektive der Studierenden erforscht, was die vorliegende Studie insbesondere hinsichtlich mittelfristiger Effekte fokussiert. Mittels eines qualitativen Fallstudiendesigns werden die Interviewdaten vier amerikanischer Deutschlernender untersucht, die sich vier Wochen in Österreich aufhielten und in einem Zeitraum von bis zu 40 Monaten nach ihrem Aufenthalt wiederholt befragt wurden. Die Ergebnisse zeigen, dass viele Auswirkungen eines solchen Aufenthalts aus studentischer Perspektive mittelfristig verblassen, auch wenn der Auslandsaufenthalt im Gesamten weiterhin als einflussreiche Erfahrung wahrgenommen wird.
Hydromagnetic convection in a rapidly rotating fluid layer

The linear stability of a rotating, electrically conducting viscous layer, heated from below and cooled from above, and lying in a uniform magnetic field is examined, using the Boussinesq approximation. Several orientations of the magnetic field and rotation axes are considered under a variety of different surface conditions. The analysis is, however, limited to large Taylor numbers, T, and large Hartmann numbers, M. (These are non-dimensional measures of the rotation rate and magnetic field strength, respectively.) Except when field and rotation are both vertical, the most unstable mode at marginal stability has the form of a horizontal roll whose orientation depends in a complex way on the directions and strengths of the field and angular velocity. For example, when the field is horizontal and the rotation is vertical, the roll is directed parallel to the field, provided that the field is sufficiently weak. In this case, the Rayleigh number, R (the non-dimensional measure of the applied temperature contrast) must reach a critical value, Rc, which is O(T2/5) before convection will occur. If, however, the field is sufficiently strong [T = O(M4)], the roll makes an acute angle with the direction of the field, and Rc = O(T1/2), i.e. the critical Rayleigh number is much smaller than when the magnetic field is absent. Also, in this case the mean applied temperature gradient and the wavelength of the tesselated convection pattern are both independent of viscosity when the layer is marginally stable. Furthermore, the Taylor-Proudman theorem and its extension to the hydromagnetic case are no longer applicable even qualitatively. Over the interior of the layer, however, the Coriolis forces to which the convective motions are subjected are, to leading order, balanced by the Lorentz forces. The results obtained in this paper have a bearing on the possibility of a thermally driven steady hydromagnetic dynamo.
A new magnetic anisotropy

A new discovery has been made in the field of magnetic materials that manifests itself in the form of a displaced hysteresis loop. In addition, although from the same basic phenomena, the magnetic material has only one stable orientation in a magnetic field. In particular, it can be turned through 180/spl deg/ and it will still return to its original orientation. The material that exhibits this property is a compact of fine particles of cobalt (100-1000 /spl Aring/) that have a cobaltous oxide coating.
Inelastic electron tunneling spectroscopy study of ultrathin HfO2 and HfAlO

We have studied inelastic electron tunneling spectroscopy (IETS) in silicon metal-oxide-semiconductor systems with HfO2 and aluminum-doped HfO2 (HfAlO) as gate dielectrics. Samples with a thermal SiO2 layer (∼2 nm) were used to obtain reference spectra for the study. Information on chemical bonding structures and compositions of ultrathin HfO2 and HfAlO has been revealed by the IETS data. The bias polarity dependence of IETS has enabled differentiation of microstructures either near the gate electrode interface or near the silicon substrate interface.
CD25bright NK cells display superior function and metabolic activity under regulatory T cell-mediated suppression

ABSTRACT Infusion of natural killer (NK) cells is an attractive therapeutic modality in patients with cancer. However, the activity of NK cells is regulated by several mechanisms operating within solid tumors. Regulatory T (Treg) cells suppress NK cell activity through various mechanisms including deprivation of IL-2 via the IL-2 receptor alpha (CD25). Here, we investigate CD25 expression on NK cells to confer persistence in Treg cells containing solid tumor models of renal cell carcinoma (RCC). Compared with IL-2, stimulation with IL-15 increases the expression of CD25 resulting in enhanced response to IL-2 as evidenced by increased phosphorylation of STAT5. Compared with CD25dim NK cells, CD25bright NK cells isolated from IL-15 primed NK cells display increased proliferative and metabolic activity as well as increased ability to persist in Treg cells containing RCC tumor spheroids. These results support strategies to enrich for or selectively expand CD25bright NK cells for adoptive cellular therapy of NK cells.
Comparison of cardiac image-derived input functions for quantitative whole body [18F]FDG imaging with arterial blood sampling

Introduction: Dynamic positron emission tomography (PET) and the application of kinetic models can provide important quantitative information based on its temporal information. This however requires arterial blood sampling, which can be challenging to acquire. Nowadays, state-of-the-art PET/CT systems offer fully automated, whole-body (WB) kinetic modelling protocols using image-derived input functions (IDIF) to replace arterial blood sampling. Here, we compared the validity of an automatic WB kinetic model protocol to the reference standard arterial input function (AIF) for both clinical and research settings. Methods: Sixteen healthy participants underwent dynamic WB [18F]FDG scans using a continuous bed motion PET/CT system with simultaneous arterial blood sampling. Multiple processing pipelines that included automatic and manually generated IDIFs derived from the aorta and left ventricle, with and without motion correction were compared to the AIF. Subsequently generated quantitative images of glucose metabolism were compared to evaluate performance of the different input functions. Results: We observed moderate to high correlations between IDIFs and the AIF regarding area under the curve (r = 0.49–0.89) as well as for the cerebral metabolic rate of glucose (CMRGlu) (r = 0.68–0.95). Manual placing of IDIFs and motion correction further improved their similarity to the AIF. Discussion: In general, the automatic vendor protocol is a feasible approach for the quantification of CMRGlu for both, clinical and research settings where expertise or time is not available. However, we advise on a rigorous inspection of the placement of the volume of interest, the resulting IDIF, and the quantitative values to ensure valid interpretations. In protocols requiring longer scan times or where cohorts are prone to involuntary movement, manual IDIF definition with additional motion correction is recommended, as this has greater accuracy and reliability.
Is Compositionality an A Priori Principle

When reasons are given for compositionality, the arguments usually purport to establish compositionality in an almost a priori manner. I will rehearse these arguments why one could think that compositionality is a priori true, or almost a priori true, and will find all of them inconclusive. This, in itself, is no reason against compositionality, but a reason to try to establish or defend the principle on other than quasi-a priori grounds. I want to argue in this paper that there is a substantial (non vacuous) notion of compositionality that seems to be of interest for semanticists. There is also an argument for this kind of compositionality that superficially looks like one from the standard battery of arguments for compositionality but that is not quasi-a priori in the same way as the others are. Instead it rests on an empirical hypothesis of which we do not know on quasi-a priori considerations alone whether it is true or false.
The Variation Method: A Technique To Estimate The Fractal Dimension Of Surfaces

There are many definitions of the fractal dimension of an object, including box dimension. Bouligand-Minkowski dimension, and intersection dimension. Although they are all equivalent in the continuous domain, when discretized and applied to digitized data, they differ substantially. We show that the standard implementations of these definitions on self-afline curves with known fractal dimension (Weierstrass-Mandelbrot, Kiesswetter, fractional Brownian motion) yield results with errors ranging up to 5 or 10%. An analysis of the source of these errors led to a new algorithm in 1-D. called the variation method, which yielded accurate results. The variation method uses the notion of e-variation to measure the amplitude of the one-dimensional function in an e-neighborhood. The order of growth of the integral of the e-variation, as E tends toward zero, is directly related to the fractal dimension. In this paper, we extend the variation method to higher dimensions and show that, in the limit, it is equivalent to the classical box counting method. The result is an algorithm for reliably estimating the fractal dimension of surfaces or, more generally, graphs of functions of several variables. The algorithm is tested on surfaces with known fractal dimension and is applied to the study of rough surfaces.
Numerical Simulation of Moisture Diffusion in the Microstructure of Asphalt Mixtures

Laboratory tests were carried out in accordance with ASTM C664-10(2020) to measure diffusion parameters in an asphalt mixture. These diffusion parameters are effective measures for use in asphalt mixtures. However, the tests could not provide detailed images of the water vapour distribution in the asphalt mixture. To solve this problem, this study provides a method for establishing a numerical model of moisture diffusion in an asphalt mixture, and gives a more detailed picture of the water vapour movement inside the asphalt mixture. Through numerical simulation results obtained under different external conditions, it was demonstrated that water molecules were mainly concentrated in medium III after 100 days of diffusion. After 1000 days of diffusion, the water molecules gradually penetrated the asphalt film in the aggregate particles. Additionally, the water vapour concentrations in the asphalt mixture varied significantly from spot to spot, and various concentration gradients were formed at different locations. These findings revealed that water vapour concentrations in an asphalt mixture vary significantly from spot to spot, forming various concentration gradients at different locations. These findings will be helpful in revealing the mechanism of water damage caused by moisture in asphalt mixtures.
High-Energy X-Ray Timing Experiment Detections of Hard X-Ray Tails in Scorpius X-1

We report the detection of a nonthermal hard X-ray component from Sco X-1 based on the analysis of 20-220 keV spectra obtained with the High-Energy X-Ray Timing Experiment on board the Rossi X-Ray Timing Explorer satellite. We find that the addition of a power-law component to a thermal bremsstrahlung model is required to achieve a good fit in five of 16 observations analyzed. Using Proportional Counter Array data, we were able to track the movement of the source along the Z diagram, and we found that the presence of the hard X-ray tail is not confined to a specific Z position. However, we do observe an indication that the power-law index hardens with increasing , as indicated from the position on the Z diagram. We find that the derived nonthermal luminosities are ~10% of that derived for the brightest of the atoll sources.
Antileishmanial Activity of Cinnamic Acid Derivatives against Leishmania infantum

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in South America, the Mediterranean basin, and West and Central Asia. The most affected country, Brazil, reported 4297 VL cases in 2017. L. infantum is transmitted by female phlebotomine sand flies during successive blood meals. There are no validated vaccines to prevent the infection and the treatment relies on drugs that often present severe side effects, which justify the efforts to find new antileishmanial drugs. Cinnamic acid derivatives have shown several pharmacological activities, including antiparasitic action. Therefore, in the present study, the biological evaluation of cinnamic acid and thirty-four derivatives against L. infantum is reported. The compounds were prepared by several synthesis methods and characterized by spectroscopic techniques and high-resolution mass spectrometry. The results revealed that compound 32 (N-(4-isopropylbenzyl)cinnamamide) was the most potent antileishmanial agent (IC50 = 33.71 μM) with the highest selectivity index (SI > 42.46), followed by compound 15 (piperonyl cinnamate) with an IC50 = 42.80 μM and SI > 32.86. Compound 32 was slightly less potent and nineteen times more selective for the parasite than amphotericin B (MIC = 3.14 uM; SI = 2.24). In the molecular docking study, the most likely target for the compound in L. infantum was aspartyl aminopeptidase, followed by aldehyde dehydrogenase, mitochondrial. The data obtained show the antileishmanial potential of this class of compounds and may be used in the search for new drug candidates against Leishmania species.
A random utility family that includes many of the ‘classical’ models and has closed form choice probabilities and choice reaction times

A large class of random utility models can be expressed in terms of multivariate (dependent) Weibull distributions. This class includes Luce's choice model, McFadden's generalized extreme value class, and Tversky's elimination by aspects model. A major advantage of this class is that one can obtain simple closed form representations of the predicted choice probabilities and reaction times. In this paper I develop a ‘process’ model that gives a natural interpretation of the origins of these models, and discuss various limitations, and possible extensions, of such models.
Wide-band multiport antenna characterization by polarimetric RCS measurements

A theoretical description of the scattering of multiport antennas is derived in accordance with the polarimetric radar target characterization. For two-port antennas with dual linear orthogonal polarization, a procedure for the determination of the antenna mode scattering parameters and the structural scattering parameters of the complete polarimetric antenna scattering matrix [S] is given. A measurement setup and experimental results of wide-band polarimetric radar cross section (RCS) antenna measurements are presented. For two-port antennas, in total, 24 unknowns have to be determined. The load variation method is used. The polarimetric RCS antenna measurement is especially advantageous over a wide bandwidth; for example 2-40 GHz with only one single calibration. From the antenna scattering matrix [S], the antenna parameters like polarimetric gain, optimum gain, gain bandwidth, wave admittance, structural scattering, etc., are derived. Results are shown for an X-band horn antenna and a 2-18-GHz dual linearly polarized horn. The measurement technique and evaluation gives the most complete and very accurate information about antenna radiation, antenna characteristics, and scattering obtainable with one single measurement setup. Some quantities determined here, like the maximum available gain and the polarization characteristics, are difficult to access with standard transmission measurements. No cable from the antenna to the receiver is necessary. This helps avoid some difficulties usually experienced at low signal levels.
Modeling the Transient Temperature Distribution within a Hydrogen Cylinder during Refueling

We report a simplified 2-dimensional axisymmetric model for predicting the gas temperature and pressure rise in a hydrogen cylinder during the fill process. The model predictions were compared with in-situ measurements of the average temperature rise and temperature distribution inside a type 3, 74 L hydrogen cylinder filled to 35 MPa.
Tuneable visible resonances in crescent shaped nano-split-ring resonators

Electron beam lithography was used to fabricate gold crescent shaped split-ring resonators with 30 nm minimum feature size. By varying the crescent’s arc length over a range of nanometer-scale dimensions the authors demonstrate the tuneability of visible resonances within such structures. Results, which correlate closely with those predicted using finite-difference time-domain modeling, open the way for these devices to be used in near-field biological sensing.