Miracle-dz/UniFAR-FTUs huggingface dataset:
Acoustic Emissions of Nearly Steady and Uniform Granular Flows: A Proxy for Flow Dynamics and Velocity Fluctuations

The seismic waves emitted during granular flows are generated by different sources: high frequencies by interparticle collisions and low frequencies by global motion and large scale deformation. To unravel these different mechanisms, an experimental study has been performed on the seismic waves emitted by dry, dense, quasi‐steady granular flows. The emitted seismic waves were recorded using shock accelerometers and the flow dynamics were captured with a fast camera. The mechanical characteristics of the particle collisions were analyzed, along with the intervals between collisions and the correlations in particles' motion. The high‐frequency seismic waves (1–50 kHz) were found to originate from particle collisions and waves trapped in the flowing layer. The low‐frequency waves (20–60 Hz) were generated by particles' oscillations along their trajectories, that is, from cycles of dilation/compression during coherent shear. The profiles of granular temperature (i.e., the mean squared value of particle velocity fluctuations) and average velocity were measured and related to each other, then used in a simple steady granular flow model, in which the seismic signal consists of the variously attenuated contributions of shear‐induced Hertzian collisions throughout the flow, to predict the rate at which seismic energy was emitted. Agreement with the measured seismic power was reasonable, and scaling laws relating the seismic power, the shear strain rate and the inertial number were derived. In particular, the emitted seismic power was observed to be approximately proportional to the root mean square velocity fluctuation to the power 3.1 ± 0.9, with the latter related to the mean flow velocity.
Exceptional times when the KPZ fixed point violates Johansson’s conjecture on maximizer uniqueness

In 2002, Johansson conjectured that the maximum of the Airy2 process minus the parabola x is almost surely achieved at a unique location [Joh03, Conjecture 1.5]. This result was proved a decade later by Corwin and Hammond [CH14, Theorem 4.3]; Moreno Flores, Quastel and Remenik [FQR13]; and Pimentel [Pim14]. Up to scaling, the Airy2 process minus the parabola x 2 arises as the fixed time spatial marginal of the KPZ fixed point when initialized from narrow wedge initial data. We extend this maximizer uniqueness result to the fixed time spatial marginal of the KPZ fixed point when initialized from any element of a very broad class of initial data. None of these results rules out the possibility that at random times, the KPZ fixed point spatial marginal violates maximizer uniqueness. We prove that, for a very broad class of initial data, it is with positive probability that the set of such times is non-empty, and that, conditionally on this event, this set almost surely has Hausdorff dimension two-thirds. In terms of directed polymers, these times of maximizer non-uniqueness are instants of instability in the zero temperature polymer measure—moments at which the endpoint jumps from one location to another. Our analysis relies on the exact formula for the distribution function of the KPZ fixed point obtained by Matetski, Quastel and Remenik in [MQR21b], the variational formula for the KPZ fixed point involving the Airy sheet constructed by Dauvergne, Ortmann and Virág in [DOV18], and the Brownian Gibbs property for the Airy2 process minus the parabola x 2 demonstrated by Corwin and Hammond in [CH14].
Superpixel-based Refinement for Object Proposal Generation

Precise segmentation of objects is an important problem in tasks like class-agnostic object proposal generation or instance segmentation. Deep learning-based systems usually generate segmentations of objects based on coarse feature maps, due to the inherent downsampling in CNNs. This leads to segmentation boundaries not adhering well to the object boundaries in the image. To tackle this problem, we introduce a new superpixel-based refinement approach11Code is available at: https://www.inf. uni-hamburg.de/spxrefinement on top of the state-of-the-art object proposal system AttentionMask. The refinement utilizes superpixel pooling for feature extraction and a novel superpixel classifier to determine if a high precision superpixel belongs to an object or not. Our experiments show an improvement of up to 26.0% in terms of average recall compared to original AttentionMask. Furthermore, qualitative and quantitative analyses of the segmentations reveal significant improvements in terms of boundary adherence for the proposed refinement compared to various deep learning-based state-of-the-art object proposal generation systems.
Conformal scattering and the Goursat problem for Dirac fields in the interior of charged spherically symmetric black holes

In this paper, we construct a conformal scattering theory for Dirac fields in the interior of a Reissner–Nordström-like black hole, between the black hole event horizon and the Cauchy horizon. The main result is a resolution of the characteristic Cauchy problem for the Dirac equation on the horizons by solving a system of wave equations and re-interpreting its solution as the components of the required Dirac solution.
An approximate analytic solution to the coupled problems of coronal heating and solar-wind acceleration

Between the base of the solar corona at $r=r_\textrm {b}$ and the Alfvén critical point at $r=r_\textrm {A}$, where $r$ is heliocentric distance, the solar-wind density decreases by a factor $ \mathop > \limits_\sim 10^5$, but the plasma temperature varies by a factor of only a few. In this paper, I show that such quasi-isothermal evolution out to $r=r_\textrm {A}$ is a generic property of outflows powered by reflection-driven Alfvén-wave (AW) turbulence, in which outward-propagating AWs partially reflect, and counter-propagating AWs interact to produce a cascade of fluctuation energy to small scales, which leads to turbulent heating. Approximating the sub-Alfvénic region as isothermal, I first present a brief, simplified calculation showing that in a solar or stellar wind powered by AW turbulence with minimal conductive losses, $\dot {M} \simeq P_\textrm {AW}(r_\textrm {b})/v_\textrm {esc}^2$, $U_{\infty } \simeq v_\textrm {esc}$, and $T\simeq m_\textrm {p} v_\textrm {esc}^2/[8 k_\textrm {B} \ln (v_\textrm {esc}/\delta v_\textrm {b})]$, where $\dot {M}$ is the mass outflow rate, $U_{\infty }$ is the asymptotic wind speed, $T$ is the coronal temperature, $v_\textrm {esc}$ is the escape velocity of the Sun, $\delta v_\textrm {b}$ is the fluctuating velocity at $r_\textrm {b}$, $P_\textrm {AW}$ is the power carried by outward-propagating AWs, $k_\textrm {B}$ is the Boltzmann constant, and $m_\textrm {p}$ is the proton mass. I then develop a more detailed model of the transition region, corona, and solar wind that accounts for the heat flux $q_\textrm {b}$ from the coronal base into the transition region and momentum deposition by AWs. I solve analytically for $q_\textrm {b}$ by balancing conductive heating against internal-energy losses from radiation, $p\,\textrm {d} V$ work, and advection within the transition region. The density at $r_\textrm {b}$ is determined by balancing turbulent heating and radiative cooling at $r_\textrm {b}$. I solve the equations of the model analytically in two different parameter regimes. In one of these regimes, the leading-order analytic solution reproduces the results of the aforementioned simplified calculation of $\dot {M}$, $U_\infty$, and $T$. Analytic and numerical solutions to the model equations match a number of observations.
An Optimal Energy-Saving Home Energy Management Supporting User Comfort and Electricity Selling With Different Prices

In this study, we investigate the operation of an optimal home energy management system (HEMS) with integrated renewable energy system (RES) and energy storage system (ESS) supporting electricity selling functions. A multi-objective mixed integer nonlinear programming model, including RES, ESS, home appliances and the main grid, is proposed to optimize different and conflicting objectives which are energy cost, user comfort and PAR. The effect of different selling prices on the objectives is also considered in detail. We further develop a formula for the lower bound of energy cost to help residents or engineers quickly choose best parameters of RES and ESS for their homes during the installation process. The performance of our system is verified through extensive simulations under three different scenarios of normal, economic, and smart with different selling prices using real data, and simulation results are compared in terms of daily energy cost, PAR, user’s convenience and consecutive waiting time to use appliances. Numerical results clearly show that the economic scenario achieves 51.6% reduction of daily energy cost compared to the normal scenario while sacrificing the user’s convenience, PAR, and consecutive waiting time by 49%, 132%, and 1 hour, respectively. On the other hand, the smart scenario shows only slight degradation of user’s convenience and PAR by 2% and 18%, respectively while achieving 46.4% reduction of daily energy cost and the same level of consecutive waiting time. Furthermore, our simulation results show that a decrease of selling prices has tiny impacts on PAR and user comfort even though the daily energy cost increases.
Educational Content Linking for Enhancing Learning Need Remediation in MOOCs

Since its introduction in 2011, there have been over 4000 MOOCs on various subjects on the Web, serving over 35 million learners. MOOCs have shown the ability to democratize knowledge dissemination and bring the best education in the world to every learner. However, the disparate distances between participants, the size of the learner population, and the heterogeneity of the learners’ backgrounds make it extremely difficult for instructors to interact with the learners in a timely manner, which adversely affects learning experience. To address the challenges, in this thesis, we propose a framework: educational content linking. By linking and organizing pieces of learning content scattered in various course materials into an easily accessible structure, we hypothesize that this framework can provide learners guidance and improve content navigation. Since most instruction and knowledge acquisition in MOOCs takes place when learners are surveying course materials, better content navigation may help learners find supporting information to resolve their confusion and thus improve learning outcome and experience. To support our conjecture, we present end-to-end studies to investigate our framework around two research questions: 1) can manually generated linking improve learning? 2) can learning content be generated with machine learning methods? For studying the first question, we built an interface that present learning materials and visualize the linking among them simultaneously. We found the interface enables users to search for desired course materials more efficiently, and retain more concepts more readily. For the second question, we propose an automatic content linking algorithm based on conditional random fields. We demonstrate that automatically generated linking can still lead to better learning, although the magnitude of the improvement over the unlinked interface is smaller. 1 ar X iv :2 01 2. 15 82 6v 2 [ cs . C Y ] 1 2 Ja n 20 21
Impact of Endometriosis on Life-Course Potential: A Narrative Review

Abstract Endometriosis may exert a profound negative influence on the lives of individuals with the disorder, adversely affecting quality of life, participation in daily and social activities, physical and sexual functioning, relationships, educational and work productivity, mental health, and well-being. Over the course of a lifetime, these daily challenges may translate into limitations in achieving life goals such as pursuing or completing educational opportunities; making career choices or advancing in a chosen career; forming stable, fulfilling relationships; or starting a family, all of which ultimately alter one’s life trajectory. The potential for endometriosis to impact the life course is considerable, as symptom onset generally occurs at a time of life (menarche through menopause, adolescence through middle age) when multiple life-changing and trajectory-defining decisions are made. Using a life-course approach, we examine how the known effects of endometriosis on life-domain satisfaction may impact health and well-being across the life course of affected individuals. We provide a quasi-systematic, narrative review of the literature as well as expert opinion on recommendations for clinical management and future research directions.
Outcomes of Corneal Topography among Progressive Keratoconus Patients 12 months following Corneal Collagen Cross-Linking

Purpose This study aimed to assess the overall and specific topographic changes among patients who underwent corneal collagen cross-linking (CXL) due to progressive keratoconus. Methods This retrospective case series study was conducted at a single-arm hospital in King Abdulaziz Medical City, Riyadh. All progressive keratoconus patients who underwent CXL between January 2017 and December 2018 were included consecutively. The epi-off crosslinking technique (Dresden protocol) was applied in all patients. The topographic values were measured preoperatively and 12 months postoperatively. Patients with a history of a previous corneal procedure, corneal trauma, or any corneal scarring were excluded. Results Among our population (29 eyes of 24 patients), 58.6% of eyes were for male patients, and the mean age of the population was 27.76 ± 4.21 years. Based on the topography results, the mean values of corneal thickness at central 3 mm decreased from 473.45 ± 38 µm to 465.72 ± 41.78 µm following CXL (Z = −1.93, 95% confidence interval [CI] = 0.048–0.057, p= 0.053). Clinically significant astigmatism measurements were present in 28 (96.6%) eyes before CXL compared to 26 (89.7%) eyes after CXL. The mean values of astigmatism among the patients were 3.37 ± 2.25 diopters before and 3.67 ± 2.61 diopters after CXL (Z = −1696, 95% confidence interval [CI] = 0.085–0.096, p = 0.09). After CXL, the mean values of the front elevation at the apex changed from 33.90 ± 20.13 µm to 36.10 ± 21.09 µm (Z = −2.792, 95% [CI] = 0.003–0.006, p = 0.005). The mean values of the back elevation at the apex changed from 68.4 ± 35.66 µm to 69.90 ± 35.89 µm (Z = −0.934, 95% CI = 0.343–0.366, p = 0.35). Conclusion The topographic corneal parameters improved significantly in the patients with corneal ectasia after CXL. These results revealed the safety and efficacy of CXL in stabilizing keratoconus progression among Saudi patients at 1 year of follow-up.
Correlation of the formative time lags with the light emitted from spark discharges

Measurements of the formative time lags in homogeneous fields for different gases up to pd values of 3000 mmHg cm have been made. For overvolted gaps in dry air and oxygen a discontinuity is found in the logarithmic plot of overvoltage against formative time. This is considered to be evidence of a transition from a Townsend- to a streamer-type of discharge. No definite sign of this change has been found in hydrogen, nitrogen and pure argon. Additional evidence that the discontinuity is the transition from one initiating mechanism to another is obtained from still photographs of the sparks. These indicate that at low values of overvoltage the discharge consists of a diffuse glow and spark channel while the streamer initiated spark has a narrow constricted glow. The position of the bright constriction or knob in the gap varies with overvoltage and its position agrees with the value predicted by the Meek criterion αxcrit. = 20. The value of overvoltage at which the transition occurs decreases with pd and is about 5 % at pd = 1000 mm Hg cm and 1-5 % at pd = 3000 mmHg cm. By extrapolation it seems unlikely that the streamer mechanism will occur at minimum break-down for pd values less than 7000 mmHg cm. Oscillographic studies have shown that the disappearance of the glow to arc step is not always a satisfactory Townsend to streamer criterion. Spectra of the sparks in air show a continuum associated with the constriction in the streamer together with bright atomic lines and weakening of the band spectra.
Anxiety and Resilience of Healthcare Workers During COVID-19 Pandemic in Indonesia

Introduction The COVID-19 pandemic has an impact on the physical health and mental health of the community, including healthcare workers. Several studies have shown symptoms of depression, anxiety, and sleep disorders in healthcare workers during this pandemic. However, not many studies have examined the resilience of healthcare workers during this pandemic. Resilience is a person’s ability to rise and adapt when times are difficult and is considered to have a protective effect on mental problems. Purpose This study aims to determine the correlation between resilience and anxiety in healthcare workers during COVID-19 pandemic. Materials and Methods This research was a cross-sectional study with observational analytic methods. The respondents were healthcare workers at Dr. Soetomo Hospital as the COVID-19 referral hospital in Surabaya, East Java, Indonesia. Data were collected from 10 to 16 June 2020 by distributing online questionnaires through the Google form application. There were three questionnaires used: demographic data, the State-Trait Anxiety Inventory (STAI) questionnaire, and the Connor–Davidson Resilience Scale (CR-RISC) questionnaire. Results The 227 respondents had filled out the questionnaire online with 33% had high state anxiety and 26.9% had high trait anxiety. The mean score of the respondents’ resilience was 69 ± 15.823. The Spearman correlation test showed a significant relationship between anxiety and resilience (p <0.05), both S-Anxiety and T-Anxiety. Conclusion A significant correlation was found between the level of resilience and anxiety experienced by healthcare workers during the COVID-19 pandemic. The lower the resilience, the higher the anxiety experienced.
The Incidence, Characteristics, and Use of Suspected Nephrotoxic Drugs in Elderly Patients with Community-Acquired Acute Kidney Injury

Purpose Acute kidney injury (AKI) is a major health problem with poor prognosis. However, little is known about elderly community-acquired-AKI (CA-AKI). This study aimed to investigate the incidence, clinical characteristics, outcomes and use of suspected nephrotoxic medications after CA-AKI in the elderly. Materials and Methods A total of 36,445 patients aged over 60 years were recruited from 2013 to 2016. Through an electronic database, we collected the demographic and medical history data, and admission lab results from all patients. Results A total of 2371 patients with CA-AKI were identified. The incidence of CA-AKI was 26.03% in the elderly. The proportion of CA-AKI patients with chronic comorbidities and Charlson comorbidity index score were higher than that of non-AKI patients. After CA-AKI, the proportions of exposure to non-steroidal anti-inflammatory drugs (NSAIDs), iodine contrast agent, angiotensin converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) were significantly decreased (p < 0.001). However, the proportion of other possible nephrotoxic drugs (including aminoglycosides, glycopeptide antibiotics, antifungal agents, beta lactam antibiotics, diuretic, ferralia, adrenergic receptor agonists and drugs for cardiac insufficiency therapy) still increased after CA-AKI (p < 0.001). Compared with non-AKI patients, CA-AKI patients had higher percentage of cardiogenic shock, multiple organ failure, transferring to intensive care unit, cardio-pulmonary resuscitation, hemodialysis, and mortality (p < 0.001). Moreover, CA-AKI patients had worse prognosis when more kinds of suspected nephrotoxic drugs were used (p < 0.001). Conclusion The incidence of CA-AKI in the elderly was high, with more complex chronic complications and poor clinical outcomes. The use of most suspected nephrotoxic drugs still increased and was associated with worse prognosis after CA-AKI.
Magnitude of Self-Reported Syndromes of Sexually Transmitted Infections and Its Associated Factors Among Young Incarcerated Persons (18–29 Years) in Correctional Facilities of Gamo Gofa Zone, Southern Ethiopia

Background Sexually transmitted infection is an infection that is typically transmitted by sexual contact and may either end or develop into a sexually transmitted disease. Today, young people are recognized as groups with special health-related vulnerabilities like drug use, unprotected sex and sexually transmitted infections. Despitea number of strategies which focused on young people’s health, there was limited evidence of sexually transmitted infection among young incarcerated persons. Thus, the aim of this study was to assess the self-reported syndromes of sexually transmitted infections and associated factors among young incarcerated persons (18–29 years) in correctional facilities of the Gamo Gofa Zone, Southern Ethiopia. Methods A facility-based cross-sectional study was conducted from March 1 to 15, 2019. Simple random sampling was used to select a total of 414 prisoners. The data were entered into Epi.info version 7 and exported and analyzed using SPSS version 20. Bivariate and multivariate logistic regression analysis were carried out. Statistical significance was declared by using the p value of <0.05 at 95% confidence interval. The Results In this study, 403 respondents participated with the response rate of 97.3%. The overall prevalence of self-reported STIs was 35 (8.7%). STI syndromes before incarceration (AOR: 5.267 (95% CI: 1.863, 14.893)), not having family support (AOR; 6.645 (95% CI: 2.327, 18.975)), history of imprisonment (AOR; 2.871 (95% CI: 1.065, 7.42)), not always using condom (AOR; 7.417, (95% CI 2.526, 21.781)), alcohol use (AOR; 5.926, (95% CI 2.282, 15.392)), chat use (AOR; 4.736, (95% CI (1.387, 16.172)) and having sex with commercial sex workers (AOR; 2.764, (95% CI 1.034, 7.388)) were significantly and independently associated with self-reported STIs. Conclusion Prevalence of self-reported syndromes of STI was high. Attention is needed about sexually transmitted infections for incarcerated young people by concerned bodies, including governmental and non-governmental organizations.