Forward-Invariance and Wong-Zakai Approximation for Stochastic Moving Boundary Problems

We discuss a class of stochastic second-order PDEs in one space-dimension with an inner boundary moving according to a possibly non-linear, Stefan-type condition. We show that proper separation of phases is attained, i.e., the solution remains negative on one side and positive on the other side of the moving interface, when started with the appropriate initial conditions. To extend results from deterministic settings to the stochastic case, we establish a Wong-Zakai type approximation. After a coordinate transformation the problems are reformulated and analysed in terms of stochastic evolution equations on domains of fractional powers of linear operators.Comment: 46 page

The Charm Content of W+1 Jet Events as a Probe of the Strange Quark Distribution Function

We investigate the prospects for measuring the strange quark distribution function of the proton in associated $W$ plus charm quark production at the Tevatron. The $W+c$ quark signal produced by strange quark -- gluon fusion, $sg\rightarrow W^-c$ and $\bar sg\rightarrow W^+\bar c$, is approximately 5\% of the inclusive $W+1$ jet cross section for jets with a transverse momentum $p_T(j)>10$~GeV. We study the sensitivity of the $W$ plus charm quark cross section to the parametrization of the strange quark distribution function, and evaluate the various background processes. Strategies to identify charm quarks in CDF and D\O \ are discussed. For a charm tagging efficiency of about 10\% and an integrated luminosity of 30~pb$^{-1}$ or more, it should be possible to constrain the strange quark distribution function from $W+c$ production at the Tevatron.Comment: submitted to Phys. Lett. B, Latex, 12 pages + 4 postscript figures encoded with uufile, FSU-HEP-930812, MAD/TH/93-6, MAD/PH/788. A postscript file with text and embedded figures is available via anonymous ftp at hepsg1.physics.fsu.edu, file is /pub/keller/fsu-hep-930812.p

Relationship between the COVID-19 pandemic and structural inequalities within the pediatric trauma population

BACKGROUND: The COVID-19 pandemic disrupted social, political, and economic life across the world, shining a light on the vulnerability of many communities. The objective of this study was to assess injury patterns before and after implementation of stay-at-home orders (SHOs) between White children and children of color and across varying levels of vulnerability based upon children\u27s home residence. METHODS: A multi-institutional retrospective study was conducted evaluating patients \u3c 18 years with traumatic injuries. A Control cohort from an averaged March-September 2016-2019 time period was compared to patients injured after SHO initiation-September 2020 ( COVID cohort). Interactions between race/ethnicity or social vulnerability index (SVI), a marker of neighborhood vulnerability and socioeconomic status, and the COVID-19 timeframe with regard to the outcomes of interest were assessed using likelihood ratio Chi-square tests. Differences in injury intent, type, and mechanism were then stratified and explored by race/ethnicity and SVI separately. RESULTS: A total of 47,385 patients met study inclusion. Significant interactions existed between race/ethnicity and the COVID-19 SHO period for intent (p \u3c 0.001) and mechanism of injury (p \u3c 0.001). There was also significant interaction between SVI and the COVID-19 SHO period for mechanism of injury (p = 0.01). Children of color experienced a significant increase in intentional (COVID 16.4% vs. Control 13.7%, p = 0.03) and firearm (COVID 9.0% vs. Control 5.2%, p \u3c 0.001) injuries, but no change was seen among White children. Children from the most vulnerable neighborhoods suffered an increase in firearm injuries (COVID 11.1% vs. Control 6.1%, p = 0.001) with children from the least vulnerable neighborhoods having no change. All-terrain vehicle (ATV) and bicycle crashes increased for children of color (COVID 2.0% vs. Control 1.1%, p = 0.04 for ATV; COVID 6.7% vs. Control 4.8%, p = 0.02 for bicycle) and White children (COVID 9.6% vs. Control 6.2%, p \u3c 0.001 for ATV; COVID 8.8% vs. Control 5.8%, p \u3c 0.001 for bicycle). CONCLUSIONS: In contrast to White children and children from neighborhoods of lower vulnerability, children of color and children living in higher vulnerability neighborhoods experienced an increase in intentional and firearm-related injuries during the COVID-19 pandemic. Understanding inequities in trauma burden during times of stress is critical to directing resources and targeting intervention strategies

Top-performing math students in 82 countries : An integrative data analysis of gender differences in achievement, achievement profiles, and achievement motivation

The present integrative data analysis examined gender differences in achievement, achievement profiles, and achievement motivation in mathematics, reading, and science among 113,864 top-performing adolescent math students (top 5% in their respective countries). To do this, we applied the same analysis protocol to representative individual participant data from six cycles of the Programme for International Student Assessment (PISA 2000–2015; 82 countries) and integrated the results by using meta-analytical random coefficient models. We found that in the group of top-performing math students, male students were overrepresented (mean female-to-male ratio 1:1.50, 95% CI [1:1.58, 1:1:43]). Furthermore, female students possessed better reading skills (mean d = –0.23, 95% CI [–0.25, –0.21]) and more positive reading attitudes (–0.64, 95% CI [–0.69, –0.60] ≤ mean d ≤ –0.38, 95% CI [–0.46, –0.30]). Male students had stronger math self-efficacy (mean d = 0.32, 95% CI [0.28, 0.35]) and demonstrated mathematics-oriented achievement profiles, whereas female students’ profiles were more balanced across domains. Moreover, female students were more interested in organic and medical fields (–0.44, 95% CI [–0.48, –0.40] ≤ mean d ≤ –0.30, 95% CI [–0.34, –0.25]), whereas male students showed greater interest in physics-related topics (0.39, 95% CI [0.36, 0.43] ≤ mean d ≤ 0.54, 95% CI [0.50, 0.58]). Gender equality indicators moderated the proportion of female students in the top 5% in mathematics and explained variability in achievement profiles across countries. Results are explained by social role theory and situated expectancy–value theory, and implications for women’s underrepresentation in (specific) STEM fields are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved

Quantifying Near-Threshold CMOS Circuit Robustness

In order to build energy efficient digital CMOS circuits, the supply voltage must be reduced to near-threshold. Problematically, due to random parameter variation, supply scaling reduces circuit robustness to noise. Moreover, the effects of parameter variation worsen as device dimensions diminish, further reducing robustness, and making parameter variation one of the most significant hurdles to continued CMOS scaling. This paper presents a new metric to quantify circuit robustness with respect to variation and noise along with an efficient method of calculation. The method relies on the statistical analysis of standard cells and memories resulting an an extremely compact representation of robustness data. With this metric and method of calculation, circuit robustness can be included alongside energy, delay, and area during circuit design and optimization

Management and outcomes of traumatic hemothorax in children

Background: Adult guidelines for the management of traumatic hemothorax are well established; however, there have been no similar studies conducted in the pediatric population. The purpose of our study was to assess the management and outcomes of children with traumatic hemothorax. Materials and Methods: Following Institutional Review Board approval, we conducted a retrospective cross-sectional study of all trauma patients diagnosed with a hemothorax at a Level-1 pediatric trauma center from 2007 to 2012. Results: Forty-six children with hemothorax were identified, 23 from blunt mechanism and 23 from penetrating mechanism. The majority of children injured by penetrating mechanisms were treated with tube thoracostomy while the majority of blunt injury patients were observed (91.3% vs. 30.4% tube thoracostomy, penetrating vs. blunt, P = 0.00002). Among patients suffering from blunt mechanism, children who were managed with chest tubes had a greater volume of hemothorax than those who were observed. All children who were observed underwent serial chest radiographs demonstrating no progression and required no delayed procedures. Children with a hemothorax identified only by computed tomography, after negative plain radiograph, did not require intervention. No child developed a delayed empyema or fibrothorax. Conclusion: The data suggest that a small-volume hemothorax resulting from blunt mechanism may be safely observed without mandatory tube thoracostomy and with overall low complication rates

Heavy Quark Production and PDF's Subgroup Report

We present a status report of a variety of projects related to heavy quark production and parton distributions for the Tevatron Run II.Comment: Latex. 8 pages, 7 eps figures. Contribution to the Physics at Run II Workshops: QCD and Weak Boson Physic