Miracle-dz/UniFAR-FTUs huggingface dataset:
Mixing time of generalized Rosenthal walk on SO(n)

We prove that a uniformized variant of both the Rosenthal walk [10] and the Kac random walk [6] on SO(n) mixes in O(n 3 ) steps in total variation distance. The proof also extends easily to Rosenthal walk with fixed angle � 6 �. To the best of our knowledge, this is the first polynomial time bound for both walks. The techniques employed are mainly from representation theory of SO(n). But a crucial new ingredient is the interpretation of the Fourier coefficients of the character ratio as counting the number of particle cascade paths arising from the classical branching rules.
How Well Do Regional Climate Models Reproduce Radiation and Clouds in the Arctic? An Evaluation of ARCMIP Simulations

Downwelling radiation in six regional models from the Arctic Regional Climate Model Intercomparison (ARCMIP) project is systematically biased negative in comparison with observations from the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment, although the correlations with observations are relatively good. In this paper, links between model errors and the representation of clouds in these models are investigated. Although some modeled cloud properties, such as the cloud water paths, are reasonable in a climatological sense, the temporal correlation of model cloud properties with observations is poor. The vertical distribution of cloud water is distinctly different among the different models; some common features also appear. Most models underestimate the presence of high clouds, and, although the observed preference for low clouds in the Arctic is present in most of the models, the modeled low clouds are too thin and are displaced downward. Practically all models show a preference to locate the lowest cloud base at the lowest model grid point. In some models this happens also to be where the observations show the highest occurrence of the lowest cloud base; it is not possible to determine if this result is just a coincidence. Different factors contribute to model surface radiation errors. For longwave radiation in summer, a negative bias is present both for cloudy and clear conditions, and intermodel differences are smaller when clouds are present. There is a clear relationship between errors in cloud-base temperature and radiation errors. In winter, in contrast, clear-sky cases are modeled reasonably well, but cloudy cases show a very large intermodel scatter with a significant bias in all models. This bias likely results from a complete failure in all of the models to retain liquid water in cold winter clouds. All models overestimate the cloud attenuation of summer solar radiation for thin and intermediate clouds, and some models maintain this behavior also for thick clouds.
Applicability of Child–Langmuir collision laws for describing a dc cathode sheath in N2O

It is established which of the Child–Langmuir collision law versions are most appropriate for describing the processes in the cathode sheath in the N2O. At low pressure (up to 0.3 Torr), the Child–Langmuir law version relating to the constant ion mobility holds. At N2O pressure values starting from 0.75 Torr and above, one has to employ the law version for which it is assumed that the ion mean free path within the cathode sheath is constant. In the intermediate pressure range (between 0.3 and 0.75 Torr), neither of the Child–Langmuir law versions gives a correct description of the cathode sheath of the glow discharge in the N2O.
Prediction of Fetal Macrosomia in Patients with Gestational Diabetes Mellitus through measuring the umbilical cord thickness and glycated hemoglobin (HbA1c) levels

Background : Diabetes mellitus, one of the most prevalent medical issues, has emerged as a serious concern to pregnant women. It is linked to a number of maternal and fetal issues, including delivery traumas, perinatal death, shoulder dystocia, macrosomia, and operating room interference. Early prediction of fatal complications will improve outcome and reduce perinatal mortality. Aim and objectives : To determine whether glycated hemoglobin and umbilical cord thickness in pregnant women with diabetes can accurately predict fetus ' s macrosomia. Patients and methods : A 6-month prospective observational research study was performed on 100 women with gestational diabetes who were 28 e 29-week pregnant at Al-Hussein University Hospital. Patients had a thorough medical history review, an ultrasound assessment, and an ultrasonography examination. Result : Glycated hemoglobin and Umbilical Cord Thickness (UCT) at 27 e 28 weeks and 36 e 37 weeks of gestation were signi ﬁ cantly different across the three groups that were examined. Conclusion : Severe obstetric problems, including shoulder dystocia and postpartum hemorrhage, are caused by mac-rosomia. There are times when it is dif ﬁ cult to foresee shoulder dystocia. The group most at risk for these issues may be found, however, using macrosomia prediction. There have been documented studies using sonographic measurement for predicting fetal macrosomia. Fetal macrosomia is well predicted by the thickness of the umbilical cord and the fetal fat layer.
Decadal modulation of the Atlantic Meridional Mode on the West Antarctic climate during austral winter

Based on observations and simplified, comprehensive atmospheric models, we investigate the impact of the tropical Atlantic sea surface temperature (SST) on the West Antarctic temperature and sea ice concentration in austral winter (June-August) on decadal timescales. The tropical gradient SST anomaly (SSTA) associated with the positive phase of the Atlantic Meridional Mode (AMM) usually leads to cool anomalies over the Antarctic Peninsula (AP) and a dipole-like sea ice distribution, with ice growth in the Amundsen-Bellingshausen Sea and loss in the Ross Sea. When the AMM is in a positive phase, upward motion over the warm region in the North Atlantic and downward motion over the cold region in the South Atlantic strengthen the Southern Hemisphere Hadley cell, resulting in upper-level convergence over the southwestern Atlantic. This convergence induces a Rossby wave, leading to an anticyclone anomaly over the Amundsen-Bellingshausen Sea. Meridional component winds of this anticyclone anomaly are associated with wind-driven sea ice drift, temperature advection, and anomalous turbulence heat fluxes, leading to a dipole-like sea ice distribution and AP cooling. These findings are verified using two types of atmospheric models. Therefore, the AMM plays a vital role in modulating the decadal change in temperature and sea ice distribution in the West Antarctic.
Bistatic scattering of acoustic waves from a rough ocean bottom

Proper understanding and modeling of the bistatic scattering of sound from the ocean bottom is vital for underwater acoustics. The problem of pulse scattering from rough surfaces, Rayleigh parameter ' > 1, in the midfrequency range 200-250 Hz (A = 6m), is considered. An analytical model for scattering strength is developed and found to match with the ARSRP-93 experimental data. Mean value and higher order statistical properties of the signals received during the experiment are analyzed independently. Analysis of the higher order statistical properties shows that they are controlled by the bistatic angle only. Further analysis suggests that the major contribution to the scattering strength is generated by the O(A) scales on the bottom, thus supporting a separation of scales hypothesis. The mean value of the received signal (scattering strength) is controlled by the large scale geomorphology and the experimental geometry. It is found that Lambert's Law, which assumes infinitely small wavelength, does not explain experimental data. Small perturbation theory accounts for the wave effects involved in the problem and hence performs better. However, it underpredicts the levels of scattering in back directions by about 10 dB. The separation of scales hypothesis suggests that small features, not accounted for by the first order small perturbation solution, are responsible for enhanced scattering into back directions. A heuristic model based on combination of small perturbation and boss theory is developed, within the separation of scales framework to account for those features which, except in forward scattering, matches experimental data to within 3 dB. Thesis Supervisor: Professor Ira Dyer Title: Weber-Shaughness Professor of Ocean Engineering
Existence and non-existence of the first eigenvalue of the perturbed Hardy–Sobolev operator

In this paper we study the existence, non-existence and simplicity of the first eigenvalue of the perturbed Hardy-Sobolev operator under various assumptions on the perturbation q. We study the asymptotic behaviour of the first eigenfunction near the origin when the perturbation q is q = s, 0 < s < 1. We will also establish the best constant in a Hardy-Sobolev inequality proved by Adimurthi et al.
Frontal Dynamics near and following Frontal Collapse

Abstract A nonhydrostatic numerical model is used to simulate two-dimensional frontogenesis forced by either horizontal deformation or shear. Both inviscid frontogenesis prior to frontal collapse and frontogenesis with horizontal diffusion following collapse are considered. The numerical solutions generally agree well with semigeostrophic (SG) theory, though differences can be substantial for intense fronts. Certain deviations from SG that have been previously discussed in the literature area, upon closer examination, associated with spurious gravity waves produced by inadequate resolution or by the initialization of the numerical model. Even when spurious waves are eliminated, however, significant deviations from SG still exist: gravity waves are emitted by the frontogenesis when the cross-front scale becomes sufficiently small, and higher-order corrections to SG may also be present. In the postcollapse solutions (where they are most prominent), the emitted waves are stationary with respect to the front .
Evaluation of non-metric traits of supraorbital region in sexual dimorphism: A study in 60 adult human skulls

Sex determination is one of the essential prerequisites for identification of an individual. The skull is probably the second best area of the skeleton for determining sex following pelvis. Diverse techniques for sexing crania are based either on visually determinable descriptive features of the cranium or on exact measurements of various parts of cranium and their ratios. Inferring from observations based on morphological indicators depends largely upon the experience of the observer. In the present study, skulls of 60 individuals of known sex (30 of either) of Indian Punjab region were studied. A series of three non metric traits of supraorbital region (glabella development, superciliary ridge development, zygomatic trigone development) were taken for the study and their significance in sex determination was established. The statistical method used in the present study is Logit and Probit regression methods.After applying this method 91.5% of the skulls were correctly classified.
Imaging human retinal pigment epithelium cells using adaptive optics optical coherence tomography

Retinal pigment epithelium (RPE) cells are vital to health of the outer retina, but are often compromised in ageing and major ocular diseases that lead to blindness. Early manifestation of RPE disruption occurs at the cellular level, and while biomarkers at this scale hold considerable promise, RPE cells have proven extremely challenging to image in the living human eye. We present a novel method based on optical coherence tomography (OCT) equipped with adaptive optics (AO) that overcomes the associated technical obstacles. The method takes advantage of the 3D resolution of AO-OCT, but more critically sub-cellular segmentation and registration that permit organelle motility to be used as a novel contrast mechanism. With this method, we successfully visualized RPE cells and characterized their 3D reflectance profile in every subject and retinal location (3° and 7° temporal to the fovea) imaged to date. We have quantified RPE packing geometry in terms of cell density, cone-to-RPE ratio, and number of nearest neighbors using Voronoi and power spectra analyses. RPE cell density (cells/mm2) showed no significant difference between 3° (4,892±691) and 7° (4,780±354). In contrast, cone-to- RPE ratio was significantly higher at 3° (3.88±0.52:1) than 7° (2.31± 0.23:1). Voronoi analysis also showed most RPE cells have six nearest neighbors, which was significantly larger than the next two most prevalent associations: five and seven. Averaged across the five subjects, prevalence of cells with six neighbors was 51.4±3.58% at 3°, and 54.58±3.01% at 7°. These results are consistent with histology and in vivo studies using other imaging modalities.
Impact of the internet use on informal workers’ wages: Evidence from China

Based on the data from the China Family Panel Studies (CFPS) in 2018, the relationship between internet use and informal workers’ wages and its internal mechanism were empirically discussed using the ordinary least squares and endogenous switching regression(ESR) model. The study found that internet use could significantly raise the level of wages of informal workers, and this conclusion still holds after the endogenous problem was solved through the endogenous switching regression model. Further research found that the influences of the internet use on informal workers’ wages was heterogeneous. In other words, internet use has a more obvious impact on the wages of informal workers aged 31 to 40, 41 to 50, and 51 to 60 with the educational level of university and above in cities and towns, while it has a significant negative impact on wages of informal workers aged 16 to 20.
Charismatic Leadership Is Not One Size Fits All: The Moderation Effect of Intolerance to Uncertainty and Furlough Status During the COVID-19 Pandemic

This study aims to examine the effect of charismatic leadership on followers’ attitudinal, emotional, and well-being outcomes in a crisis setting. Combining leadership literature with Conservation of Resources and leader-follower distance theories, we propose that the effect of charismatic leadership on follower outcomes depends on the interplay between the follower's furlough status during the lockdown period and their Intolerance to Uncertainty (IU) dispositional characteristic. A cross-sectional study was conducted at two points in time: during the first lockdown (March–April 2020) and four months after the lockdown (August 2020). The final sample included 336 employees with data for both points in time (n = 199 continued to work during the lockdown, n = 137 were on furlough). The findings confirmed the study's hypotheses and revealed that charismatic leadership significantly contributed to employee outcomes only in the case of furloughed employees with low levels of IU and of continuously-employed employees with high levels of IU. It did not make a similar contribution in the edge cases—employees with low IU levels who continued to work during the lockdown or those with high levels of IU who were furloughed. This study provides novel insights into the relationship between charismatic leadership effectiveness and follower outcomes, and informs managers how to better adjust their leadership style to their followers in a crisis setting. The findings extend our knowledge about charismatic leadership by suggesting the mutual contribution of the distance dimension and employee dispositional characteristics as a boundary condition to charismatic leadership effectiveness.
Possible Mechanisms of Clear-Air Turbulence in Strongly Anticyclonic Flows

Abstract The forecasting of clear-air turbulence (CAT) continues to be a challenging problem despite progress made in the understanding of vertical shear (Kelvin–Helmholtz) instabilities. The possible connections between horizontal anticyclonic flows and CAT are addressed. Analytical expressions are derived to show that current CAT diagnostics do not correctly account for the dynamics of strongly anticyclonic situations. In gradient-balanced anticyclonic flows, nonfrontogenetical enhancement of vertical shear may lead to CAT. A review of observations, theory, and modeling is presented to support the claim that strong anticyclonic relative vorticity can also lead to CAT through the generation of gravity wave activity by geostrophic adjustment and inertial instability. CAT diagnostics are then discussed in light of these claims. Observational work is in progress to investigate the possibility of inertial instability-triggered CAT.
Full Motion and Flow Field Recovery From

We present a new computational method for recon- structing a vector velocity field from scattered, pulsed-wave ultra- sound Doppler data. The main difficulty is that the Doppler mea- surements are incomplete, for they do only capture the velocity component along the beam direction. We thus propose to combine measurements from different beam directions. However, this is not yet sufficient to make the problem well posed because 1) the angle between the directions is typically small and 2) the data is noisy and nonuniformly sampled. We propose to solve this reconstruc- tion problem in the continuous domain using regularization. The reconstruction is formulated as the minimizer of a cost that is a weighted sum of two terms: 1) the sum of squared difference be- tween the Doppler data and the projected velocities 2) a quadratic regularization functional that imposes some smoothness on the ve- locity field. We express our solution for this minimization problem in a -spline basis, obtaining a sparse system of equations that can be solved efficiently. Using synthetic phantom data, we demon- strate the significance of tuning the regularization according to the a priori knowledge about the physical property of the motion. Next, we validate our method using real phantom data for which the ground truth is known. We then present reconstruction results obtained from clinical data that originate from 1) blood flow in carotid bifurcation and 2) cardiac wall motion. Index Terms—Color Doppler imaging, color flow imaging, echocardiography, nonuniform sampling, projected sampling, pulsed wave Doppler, regularized reconstruction, shift-invariant spaces, tissue Doppler imaging, ultrasound Doppler, variational reconstruction, vector field reconstruction, velocity field recon- struction.
Assessing the effects of ROO and tariff margin on China-ASEAN free trade agreement utilization

This study investigates the effects of rule of origin (ROOs) and tariff margin on China-ASEAN Free Trade Agreement (CAFTA) utilization. Using a sample of 40,474 product-level observations with China’s imports from ASEAN countries during the period 2015 to 2021 and adopting the Logit model estimation methods, we found that larger tariff margin positively affects the use of CAFTA, whereas, the rules of origin show a negative effect on the CAFTA utilization. In order to assess the specific impact of two effects, we also calculate the relative contribution of these two effects to the CAFTA utilization by ASEAN countries, and the results show that the rules of origin play a more important role on the CAFTA utilization by each ASEAN country. Moreover, based on heterogeneity analysis, we also find that ROOs play an important role in the use of FTA by lower middle-income countries and the tariff margin play an important role in the use of FTA by upper middle-income and high-income countries. Based on the above findings, the study proposes some policy recommendations on how to increase the CAFTA utilization by reducing the ROO costs and accelerating tariff reductions.
Imaging of the electronic bonding of diamond at pressures up to 2 million atmospheres

Diamond shows unprecedented hardness. Because hardness is a measure of resistance of chemical bonds in a material to external indentation, the electronic bonding nature of diamond beyond several million atmospheres is key to understanding the origin of hardness. However, probing the electronic structures of diamond at such extreme pressure has not been experimentally possible. The measurements on the inelastic x-ray scattering spectra for diamond up to 2 million atmospheres provide data on the evolution of its electronic structures under compression. The mapping of the observed electronic density of states allows us to obtain a two-dimensional image of the bonding transitions of diamond undergoing deformation. The spectral change near edge onset is minor beyond a million atmospheres, while its electronic structure displays marked pressure-induced electron delocalization. Such electronic responses indicate that diamond’s external rigidity is supported by its ability to reconcile internal stress, providing insights into the origins of hardness in materials.
Phase stability and magnetic behavior of FeCrCoNiGe high-entropy alloy

We report an alternative FeCrCoNiGe magnetic material based on FeCrCoNi high-entropy alloy with Curie point far below the room temperature. Investigations are done using first-principles calculations and key experimental measurements. Results show that the equimolar FeCrCoNiGe system is decomposed into a mixture of face-centered cubic and body-centered cubic solid solution phases. The increased stability of the ferromagnetic order in the as-cast FeCrCoNiGe composite, with measured Curie temperature of 640 K, is explained using the exchange interactions.
Cuffless Blood Pressure Measurement Using Smartwatches: A Large-Scale Validation Study

This study aimed to evaluate the performance of cuffless blood pressure (BP) measurement techniques in a large and diverse cohort of participants. We enrolled 3077 participants (aged 18–75, 65.16% women, 35.91% hypertensive participants) and conducted followed-up for approximately 1 month. Electrocardiogram, pulse pressure wave, and multiwavelength photoplethysmogram signals were simultaneously recorded using smartwatches; dual-observer auscultation systolic BP (SBP) and diastolic BP (DBP) reference measurements were also obtained. Pulse transit time, traditional machine learning (TML), and deep learning (DL) models were evaluated with calibration and calibration-free strategy. TML models were developed using ridge regression, support vector machine, adaptive boosting, and random forest; while DL models using convolutional and recurrent neural networks. The best-performing calibration-based model yielded estimation errors of 1.33 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 6.43 mmHg for DBP and 2.31 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 9.57 mmHg for SBP in the overall population, with reduced SBP estimation errors in normotensive (1.97 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 7.85 mmHg) and young (0.24 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 6.61 mmHg) subpopulations. The best-performing calibration-free model had estimation errors of <inline-formula><tex-math notation="LaTeX">$-$</tex-math></inline-formula>0.29 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 8.78 mmHg for DBP and <inline-formula><tex-math notation="LaTeX">$-$</tex-math></inline-formula>0.71 <inline-formula><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 13.04 mmHg for SBP. We conclude that smartwatches are effective for measuring DBP for all participants and SBP for normotensive and younger participants with calibration; performance degrades significantly for heterogeneous populations including older and hypertensive participants. The availability of cuffless BP measurement without calibration is limited in routine settings. Our study provides a large-scale benchmark for emerging investigations on cuffless BP measurement, highlighting the need to explore additional signals or principles to enhance the accuracy in large-scale heterogeneous populations.