Transient Response of Shells of Revolution by Direct Integration and Modal Superposition Methods

The results of an analytical effort to obtain and evaluate transient response data for a cylindrical and a conical shell by use of two different approaches: direct integration and modal superposition are described. The inclusion of nonlinear terms is more important than the inclusion of secondary linear effects (transverse shear deformation and rotary inertia) although there are thin-shell structures where these secondary effects are important. The advantages of the direct integration approach are that geometric nonlinear and secondary effects are easy to include and high-frequency response may be calculated. In comparison to the modal superposition technique the computer storage requirements are smaller. The advantages of the modal superposition approach are that the solution is independent of the previous time history and that once the modal data are obtained, the response for repeated cases may be efficiently computed. Also, any admissible set of initial conditions can be applied

Xenon in Mercury-Manganese Stars

Previous studies of elemental abundances in Mercury-Manganese (HgMn) stars have occasionally reported the presence of lines of the ionized rare noble gas Xe II, especially in a few of the hottest stars with Teff ~ 13000--15000 K. A new study of this element has been undertaken using observations from Lick Observatory's Hamilton Echelle Spectrograph. In this work, the spectrum synthesis program UCLSYN has been used to undertake abundance analysis assuming LTE. We find that in the Smith & Dworetsky sample of HgMn stars, Xe is vastly over-abundant in 21 of 22 HgMn stars studied, by factors of 3.1--4.8 dex. There does not appear to be a significant correlation of Xe abundance with Teff. A comparison sample of normal late B stars shows no sign of Xe II lines that could be detected, consistent with the expected weakness of lines at normal abundance. The main reason for the previous lack of widespread detection in HgMn stars is probably due to the strongest lines being at longer wavelengths than the photographic blue. The lines used in this work were 4603.03A, 4844.33A and 5292.22A.Comment: 8 pages, 4 figures. Accepted by Monthly Notices of the Royal Astronomical Society, 8 January 200

Vibration characteristics of ring-stiffened orthotropic shells of revolution

Computer program solves vibration modes and frequencies of thin shells of revolution having general meridional curvature and orthotropic elastic properties in order to evaluate the dynamic behavior of structures with thin shelled components

Cost-Benefit Politics in U.S. Energy Policy

The political economy of energy policy in the United States is dominated by partisanship and industry lobbying. Both are reflected in the widespread belief that the Environmental Protection Agency (EPA) is engaged in a misguided “war on coal”—despite decades of regulatory delays, the coal industry’s status as the leading industrial source of air pollution, and compelling evidence that the benefits of EPA’s regulations vastly exceed their costs. The politics are compounded by tensions between electricity managers and environmental regulators. Much of this is driven by competing perspectives: EPA tends to have a national focus, whereas grid managers operate regionally. This Article resolves the apparent conflicts by downscaling the regulatory analyses of three high-profile EPA rules that cover conventional pollutants, air toxics, and greenhouse gases associated with climate change. We utilize complementary EPA databases and draw on several model estimates to examine the regional impacts, both costs and benefits, of regulations targeting coal-fired power plants. Overall we find little evidence of significant regional disparities, as the distribution of compliance costs and benefits is roughly commensurate with each regions’ reliance on coal-fired power, and particularly older facilities. This result follows naturally from the benefits of reducing emissions under these rules being predominantly local; as a consequence, regulatory benefits exceed costs at the regional level and typically by large margins. Further, with a few important caveats, we find that while the EPA rules will encourage many power-plant closures, most will occur in electricity markets that have sufficient excess capacity to mitigate potential threats to electricity supplies and reliability. We conclude that while interest group opposition and political partisanship are clearly both important in this context, the latter appears to hold greater sway based on varying levels of political opposition regionally and may—incrementally—be shifting in EPA’s favor.The Kay Bailey Hutchison Center for Energy, Law, and Busines

Flux calculations in an inhomogeneous Universe: weighting a flux-limited galaxy sample

Many astrophysical problems arising within the context of ultra-high energy cosmic rays, very-high energy gamma rays or neutrinos, require calculation of the flux produced by sources tracing the distribution of galaxies in the Universe. We discuss a simple weighting scheme, an application of the method introduced by Lynden-Bell in 1971, that allows the calculation of the flux sky map directly from a flux-limited galaxy catalog without cutting a volume-limited subsample. Using this scheme, the galaxy distribution can be modeled up to large scales while representing the distribution in the nearby Universe with maximum accuracy. We consider fluctuations in the flux map arising from the finiteness of the galaxy sample. We show how these fluctuations are reduced by the weighting scheme and discuss how the remaining fluctuations limit the applicability of the method.Comment: 8 pages, 10 figures, accepted for publication in MNRA

Stroke Quality Measures in Mexican Americans and Non-Hispanic Whites

Mexican Americans (MAs) have been shown to have worse outcomes after stroke than non-Hispanic Whites (NHWs), but it is unknown if ethnic differences in stroke quality of care may contribute to these worse outcomes. We investigated ethnic differences in the quality of inpatient stroke care between MAs and NHWs within the population-based prospective Brain Attack Surveillance in Corpus Christi (BASIC) Project (February 2009- June 2012). Quality measures for inpatient stroke care, based on the 2008 Joint Commission Primary Stroke Center definitions were assessed from the medical record by a trained abstractor. Two summary measure of overall quality were also created (binary measure of defect-free care and the proportion of measures achieved for which the patient was eligible). 757 individuals were included (480 MAs and 277 NHWs). MAs were younger, more likely to have hypertension and diabetes, and less likely to have atrial fibrillation than NHWs. MAs were less likely than NHWs to receive tPA (RR: 0.72, 95% confidence interval (CI) 0.52, 0.98), and MAs with atrial fibrillation were less likely to receive anticoagulant medications at discharge than NHWs (RR 0.73, 95% CI 0.58, 0.94). There were no ethnic differences in the other individual quality measures, or in the two summary measures assessing overall quality. In conclusion, there were no ethnic differences in the overall quality of stroke care between MAs and NHWs, though ethnic differences were seen in the proportion of patients who received tPA and anticoagulant at discharge for atrial fibrillation

p-16: immunohistochemical staining to differentiate an inflamed atypical nevus

In the monitoring of patients who have had metastatic melanoma, repeat skin exams at specific intervals is a crucial screening tool to prevent recurrence. At many of these visits, suspicious melanocytic lesions are biopsied to determine if they represent a return of the patient’s melanoma. Here, we present a case of a suspicious atypical melanocytic nevus discovered during a skin exam following diagnosis of metastatic melanoma to a lymph node from an unknown primary lesion. To determine whether this lesion was melanoma, p16 immunohistochemical staining was performed of both the lymph node biopsy and the nevus, and provided a reliable means for determining the nature of the nevus. This information would be helpful to readers who care for patients with a history of melanoma who require differentiation of atypical nevi from recurrence of melanoma.https://scholarlycommons.henryford.com/merf2020caserpt/1012/thumbnail.jp