Miracle-dz/UniFAR-FTUs huggingface dataset:
Direct numerical simulation of multiple cycles in a valve/piston assembly

The dynamics and multiple-cycle evolution of the incompressible flow induced by a moving piston through the open valve of a motored piston-cylinder assembly was investigated using direct numerical simulation. A spectral element solver, adapted for moving geometries using an Arbitrary Lagrange/Eulerian formulation, was employed. Eight cycles were simulated and the ensemble- and azimuthally-averaged data were found to be in good agreement with experimentally determined means and fluctuations at all measured points and times. During the first half of the intake stroke the flow field is dominated by the dynamics of the incoming jet and the vortex rings it creates. With decreasing piston speed a large central ring becomes the dominant flow feature until the top dead center. The flow field at the end of the previous cycle is found to have a dominant effect on the jet breakup and the vortex ring dynamics below the valve and on the observed significant cyclic variations. Based on statistical averaging, the evolut.
Evaluating Kinect, OpenPose and BlazePose for Human Body Movement Analysis on a Low Back Pain Physical Rehabilitation Dataset

Analyzing human motion is an active research area, with various applications. In this work, we focus on human motion analysis in the context of physical rehabilitation using a robot coach system. Computer-aided assessment of physical rehabilitation entails evaluation of patient performance in completing prescribed rehabilitation exercises, based on processing movement data captured with a sensory system, such as RGB and RGB-D cameras. As 2D and 3D human pose estimation from RGB images had made impressive improvements, we aim to compare the assessment of physical rehabilitation exercises using movement data obtained from both RGB-D camera (Microsoft Kinect) and estimation from RGB videos (OpenPose and BlazePose algorithms). A Gaussian Mixture Model (GMM) is employed from position (and orientation) features, with performance metrics defined based on the log-likelihood values from GMM. The evaluation is performed on a medical database of clinical patients carrying out low back-pain rehabilitation exercises, previously coached by robot Poppy.
A Multi-Level Analysis of the Effects of Statistics Anxiety/Attitudes on Trajectories of Exam Scores

Abstract This study explores three understudied facets—quadratic effects, change over time, and gender as a moderator—of the otherwise well-documented relationships between statistics anxiety and academic performance. Using pre- and post- course survey data among a sample of 111 undergraduate students in Social Statistics courses at a U.S. Midwestern university, we employ hierarchical linear modeling (HLM) to test for relationships between change in the six dimensions of the Statistics Anxiety Rating Scale (STARS) and exam grades over the course of the semester. We find that exam grades decreased over time, but at different rates across gender and the six STARS dimensions. We also identify a quadratic relationship between self-concept and final exam grades, as well as several gender interactions. This study highlights the multifaceted and dynamic nature of statistics anxiety/attitudes, as its relationship with academic performance is not always negative, linear, stable over time, or uniform across gender. Supplementary materials for this article are available online.
Split-Transformer Impute (STI): Genotype Imputation Using a Transformer-Based Model

With recent advances in DNA sequencing technologies, researchers are able to acquire increasingly larger volumes of genomic datasets, enabling the training of powerful models for downstream genomic tasks. However, genome scale dataset often contain many missing values, decreasing the accuracy and power in drawing robust conclusions drawn in genomic analysis. Consequently, imputation of missing information by statistical and machine learning methods has become important. We show that the current state-of-the-art can be advanced significantly by applying a novel variation of the Transformer architecture, called Split-Transformer Impute (STI), coupled with improved preprocessing of data input into deep learning models. We performed extensive experiments to benchmark STI against existing methods using resequencing datasets from human 1000 Genomes Project and yeast genomes. Results establish superior performance of our new methods compared to competing genotype imputation methods in terms of accuracy and imputation quality score in the benchmark datasets.
Positron scattering by potassium

Coupled-state calculations in a K(4s,4p,5s,5p,3d) + Ps(1s,2s,2p,3s,3p,3d) approximation are reported for positron scattering by ground-state potassium in the energy range 0.5 - 60.0 eV. Comparison is made with the earlier work of Hewitt and co-workers in a K(4s,4p,5s,5p) + Ps(1s,2s,2p) approximation. For the first time cross sections for positronium formation in n = 3 states are obtained. We support the conclusion of Hewitt et al that above about 4 eV positronium formation is mainly into excited states, although we disagree significantly on the distribution of the excited state population. Fairly good agreement is obtained with the measurements of Zhou and co-workers for total positronium formation when scaling is used to estimate the amount of positronium in states with . Our cross sections for elastic scattering, 4s - 4p, 4s - 5s and 4s - 5p excitation of potassium are in relatively good agreement with those of Hewitt and co-workers but our calculations also emphasize the importance of the 4s - 3d excitation which is omitted in their approximation. Atom excitation to the n = 5 level is found to be a relatively minor process. Good agreement is obtained with the total cross section measurements of Kwan and co-workers and Parikh and co-workers when these are normalized upwards by 10% and corrections made for near forward elastic scattering. This upward normalization lies within the quoted overall 21% error on the measurements. Below 4 eV the calculated total cross section is dominated by elastic scattering while at high energies 4s - 4p excitation is the main contributor. In the vicinity of 6 eV, and consistent with the measurements of Parikh and co-workers, the total cross section displays a pronounced peak which derives largely, although not totally, from positronium formation. Positronium formation is not important above about 30 eV.
Inclusive Pedagogy Strategies to Introduce High Schoolers to Systems Biology

Women and non-white racial and ethnic groups remain underrepresented in science, technology, engineering, and math (STEM). To achieve a more diverse and equitable STEM workforce, the recruitment and retention of these historically marginalized communities in postsecondary education will also need to increase. Recently, the lens has turned to pedagogy and how creating a more inclusive classroom environment can foster STEM identity in previously marginalized communities. This work focuses on developing and piloting systems biology education modules designed to promote an inclusive learning environment in a summer outreach program for high school students by (1) utilizing a hybrid of unplugged activities with coded simulation and (2) a female-oriented problem statement. Based on initial findings in our pilot program, we anticipate that these techniques will enable students with limited prior computational experience to feel more comfortable and able to complete tasks, thereby increasing their self-efficacy and STEM identity. These modules could be a valuable tool for practitioners teaching high school or early college-level computational courses who instruct students with varied coding experience. Additionally, our analysis of the use of a female-oriented problem statement on female-identifying students' perceived self-efficacy provides potential evidence of the usefulness of representative problem statements in engaging underrepresented student populations. These techniques could be adapted to address a variety of contexts across STEM disciplines and other fields to foster inclusive learning environments.
The role of ecology and geography in the evolution of habitat isolation and sexual isolation among sister species of host-plant-specific insects

While ecology and geography can play important roles in the evolution of reproductive isolation across the speciation continuum, the few studies to date examining their relative contributions have largely focused on the early stages of speciation. Studies exploring the evolution of multiple reproductive barriers among divergent lineages, where speciation is nearly complete, are also needed to gain a fuller understanding of the mechanisms promoting and constraining the speciation process. We examine the later stage of speciation by comparing the strength of habitat isolation and sexual isolation among closely related species of gall-forming wasps in the genus Belonocnema experiencing divergent ecologies due to different hos plant use and variable rates of migration due to geography. We found that the strength of both habitat isolation and sexual isolation is lowest among allopatric species pairs with the same host plant association, followed by allopatric species with different host plant association, and highest between sympatric species with different host-plant associations. This pattern strongly suggests that both ecology due to divergent host use, and geography contribute to the evolution of these two reproductive barriers. Notably, reproductive character displacement contributes to nearly half of the strength of both habitat isolation and sexual isolation in sympatry.
Leo I - The youngest Milky Way dwarf spheroidal galaxy?

We have obtained deep CCD photometry of ∼16 000 stars in the Leo I dwarf spheroidal galaxy (dSph), the most distant known satellite of the Milky Way Galaxy. The resulting color-magnitude diagrams (CMDs) of Leo I reveal several striking features. (1) There is a well-defined red giant branch (RGB) which is very blue and has a flatter slope than all other dwarf dSphs and Galactic globular clusters. The tip of the RGB is at I TRGB =18.25±0.10 mag and (V−I) TRGB =1.43±0.02 mag. (2) Unlike all of the other known dSphs; Leo I has no obvious horizontal branch; however, it does show a strong clump of red giants at V≃22.4 mag and (V−I)≃0.8 mag. (3) The CMD of Leo I shows ∼50 anomalous Cepheid candidates
Spatial and temporal transcriptomics of SHH-medulloblastoma with chromothripsis identifies multiple genetic clones that resist to treatment and lead to relapse

Paediatric medulloblastomas with chromothripsis are characterised by high genomic instability and are among the tumours with the worst prognosis. However, the determinants of their aggressiveness and the molecular makeup of chromothriptic medulloblastoma are not well understood. Here, we applied spatial transcriptomics to profile a cohort of 13 chromothriptic and non-chromothriptic medulloblastomas from the same molecular subgroup. Our data reveal a higher extent of spatial intra-tumour heterogeneity in chromothriptic medulloblastomas, which is associated with increased proliferation and stemness, but lower immune infiltration and differentiation. Spatial mapping of genetic subclones of the same tumour identify a regionally distinct architecture and clone-specific phenotypic features, with distinct degrees of differentiation, proliferation and immune infiltration between clones. We conducted temporal profiling of 11 patient-derived xenografts from chromothriptic medulloblastomas, covering the transition from the minimal residual disease stage to treatment-resistant regrown tumours. In chromothriptic medulloblastoma, an ecosystem of cells from multiple genetic clones resisting treatment and leading to relapse highlighted the importance of multi-clone interplay. Finally, we identified a potential role for tumour microtubes in treatment resistance in chromothriptic medulloblastoma, suggesting cell network communication as a putative target. Highlights Biological insights Medulloblastomas with chromothripsis are characterised by higher spatial intra-tumour heterogeneity, proliferation and stemness, but lower immune infiltration and differentiation, as compared with non-chromothriptic medulloblastomas Spatially aware genetic clone assignment identifies phenotypic features such as degree of differentiation, proliferation and immune infiltration enriched in specific clones Cells from distinct genetic clones resist to treatment and give rise to relapse in patient-derived xenografts of medulloblastoma with chromothripsis Tumour microtubes point to putative molecular processes implicated in treatment resistance in chromothriptic medulloblastoma Technological advances Validation of the spatial representation of patient-derived xenograft models, providing novel insights into the faithfulness of such models to study cancer Spatial mapping of clones based on spatial transcriptomics and copy-number variant profiling
Exploration of Speech Induced Suppression using Functional Near-Infrared Spectroscopy (fNIRS)

Speech-Induced Suppression (SIS) is a suppression of brain activity by speech. It is believed to be caused by the internal predictions of the consequences of speech movements which lead to attenuation of related neural activity (1, 2). Previous research (3) showed that SIS of the EEG signal can be observed in some speaking tasks but the results were not consistent. This study found that fNIRS can be used to test neural activity related to speech production. Grand averaged signals showed that conditions involving vocalisation actually elicited higher activity than those without vocalisation. When statistical models were fitted to the obtained data, and controlled for participant-related variation, these results did not hold. No statistically significant differences between conditions were found. Even though haemoglobin concentration changes are slower than ERPs, they capture the neural activity underlying speech-production processes. The current results suggest that fNIRS can be used to study speech production.
Stress-induced brain responses are associated with BMI in women

Overweight and obesity are associated with altered stress reactivity and increased inflammation. However, it is not known whether stress-induced changes in brain function scale with BMI and if such associations are driven by peripheral cytokines. Here, we investigate multimodal stress responses in a large transdiagnostic sample using predictive modeling based on spatio-temporal profiles of stress-induced changes in activation and functional connectivity. BMI is associated with increased brain responses as well as greater negative affect after stress and individual response profiles are associated with BMI in females ( p _perm < 0.001), but not males. Although stress-induced changes reflecting BMI are associated with baseline cortisol, there is no robust association with peripheral cytokines. To conclude, alterations in body weight and energy metabolism might scale acute brain responses to stress more strongly in females compared to males, echoing observational studies. Our findings highlight sex-dependent associations of stress with differences in endocrine markers, largely independent of peripheral inflammation. In humans, brain responses to stress are associated with their body mass index, driven mostly by females. Predictive modeling showed that this link was better explained by changes in endocrine instead of immune systems.
Using the correlation exponent to decide whether an economic series is chaotic

We consider two ways of distinguishing deterministic time-series from stochastic white noise; the Grassberger-Procaccia correlation exponent test and the Brock, Dechert, Scheinkman (or BDS) test. Using simulated data to test the power of these tests, the correlation exponent test can distinguish white noise from chaos. It cannot distinguish white noise from chaos mixed with a small amount of white noise. With i.i. d. as the null, the BDS correctly rejects the null when the data are deterministic chaos. Although the BDS test may also reject the null even when the data are stochastic, it may be useful in distinguishing between linear and nonlinear stochastic processes. Copyright 1992 by John Wiley & Sons, Ltd.
Bistatic scattering and depolarization by randomly rough surfaces: application to the natural rough surfaces in X-band

Abstract The scattering of waves by random rough surfaces has important applications in the remote sensing of oceans and land. The problem of developing a model for rough surfaces is very difficult since, at best, the scattering coefficient σ0 is dependent upon (at least) the radar frequency, geometrical and physical parameters, incident and observation angles, and polarization. The problem of electromagnetic scattering from a randomly rough surface is analysed using the Kirchhoff approximation (stationary phase, scalar approximation), the small-perturbation model and the two-scale models. A first major new consideration in this paper is the polarimetric signature calculations as a function of the transmitter location and receiver location for a bistatic radio-link. We calculate the like- and cross-polarized received power directly using the scattering coefficients, without calculating the Mueller matrix. Next, a study of the regions of validity of the Kirchhoff and small-perturbation rough surface scattering models (in the bistatic case) is presented. Comparisons between the numerical calculations and the models are made for various surface rms heights and correlation lengths both normalized to the incident wavenumber (denoted by σ and L, respectively). By using these two parameters to form a two-dimensional space, the approximate regions of validity are then established. The second major new consideration is the development of a theoretical two-scale model describing bistatic reflectivity as well as the numerical results computed for the bistatic radar cross section from rough surfaces especially from the sea and snow-covered surfaces. The results are used to show the Brewster angle effect on near-grazing angle scattering.
Magnetization, accretion, and outflows in young stellar objects

Abstract We review the theory of the formation and gravitational collapse of magnetized molecular cloud cores, leading to the birth of T Tauri stars surrounded by quasi-Keplerian disks whose accretion is driven by the magnetorotational instability (MRI). Some loss of magnetic flux during the collapse results typically in a dimensionless mass-to-flux ratio for the star plus disk of λ0 ≈ 4. Most of the mass ends up in the star, while almost all of the flux and the angular momentum ends up in the disk; therefore, a known mass for the central star implies a computable flux in the surrounding disk. A self-contained theory of the MRI that drives the viscous/resistive spreading in such circumstances then yields the disk radius needed to contain the flux trapped in the disk as a function of the age t. This theory yields analytic predictions of the distributions with distance ϖ from the central star of the surface density Σ(ϖ), the vertical magnetic field Bz(ϖ), and the (sub-Keplerian) angular rotation rate Ω (ϖ). We discuss the implications of this picture for disk-winds, X-winds, and funnel flows, and we summarize the global situation by giving the energy and angular-momentum budget for the overall problem.
A Note on Rigid Dumbbell Solutions at High Shear Rates

Both Hinch and Leal and Stewart and Sorensen solved the diffusion equation for the configurational distribution function of rigid dumbbells at high shear rates by several different numerical methods and obtained asymptotic expressions for the viscometric functions. In this note we have considered only a contracted distribution function which, however, can be calculated analytically. This contracted distribution function not only contains interesting information about the behavior of rigid dumbbells at high shear rates but can also be used to find an exact asymptotic expression for the first normal‐stress coefficient. By introducing modified time constants, the results of the present paper, which have been derived for rigid dumb‐bells with Oseen‐Burgers hydrodynamic interaction, can easily be generalized to rigid multibead rods and Rotne‐Prager‐Yamakawa hydrodynamic interaction.
On relativistic wave equations for particles of arbitrary spin in an electromagnetic field

The investigations of Dirac (1936) on relativistic wave equations for particles with arbitrary spin have recently been followed up by one of us (Fierz, 1939, referred to as (A)) It was there found possible to set up a scheme of second quantization in the absence of an external field, and to derive expressions for the current vector and the energy-momentum tensor. These considerations will be extended in the present paper to the case when there is an external electromagnetic field, but we shall in the first instance disregard the second quantization and confine ourselves to a c -number theory. The difficulty of this problem is illustrated by the fact that the most immediate method of taking into account the effect of the electromagnetic field, proposed by Dirac (1936), leads to inconsistent equations as soon as the spin is greater than 1.
On the geometry of Hele-Shaw flows with small surface tension

We discuss the Hele‐Shaw problem in the plane in two basic cases. The first one deals with the classical situation of injection through a unique source in a finite region. The second one is concerned with the free boundary extending to the point at infinity. Starting with the earlier works of L. A. Galin [9] and P. Ya. Polubarinova-Kochina [19, 20], various aspects of the planar Hele‐Shaw viscous flows with vanishing surface tension were investigated by a number of scientists. It is known [31] that in the zero-surface-tension Hele‐Shaw problem with an initial region with an analytic boundary the classical solution exists locally in time. Recently [25], it became clear that the model could be interpreted as a particular case of the abstract Cauchy problem, and thus, the classical solvability (locally in time) may be proved using the nonlinear abstract Cauchy‐Kovalevskaya Theorem.
The effect of pre-slaughter electrical stunning on bleeding efficiency, meat quality, histology, and microbial count of several goat muscles

This study was designed to compare the effect of non-electrical stunning and electrical stunning on bleeding efficiency, meat quality characteristics, bacterial count, and histology of longissimus thoraces, semitendinosus, biceps femoris, infraspinatus, semimembranosus, and triceps brachii muscles of goats. Forty goats were randomly divided into two groups: electrical stunning and non-electrical stunning with 20 animals each. Low frequency head-only electrical stunning of 1 Amp for 3 s at a frequency of 50 Hz was used. The slaughter was performed by severing the carotid artery, jugular vein, trachea, and oesophagus. Six muscles were kept in a chiller at 3–4 ºC for 24 h before quality measurements. Samples from the infraspinatus, longissimus thoraces, and semitendinosus muscles were preserved to evaluate histological features. Muscle samples from the non-electrical stunning group had substantially higher blood loss and lower bacterial counts after 72 h across the six muscles compared to the electrical stunning group. No significant differences in meat quality parameters were evident between the two groups. The stained sections of the electrically-stunned muscle samples detected alteration phenomena due to the presence of muscle fibres with split myofibres and myofibres with central rather than peripheral nuclei. Electrical stunning prior to slaughter increased bacterial contamination, decreased blood loss, and altered the position of muscle nuclei.