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Koenen Karestan C.; Stellman Jeanne Mager; Stellman Steven D.; Sommer John F. Jr. 《Canadian Metallurgical Quarterly》2003,71(6):980
Risk factors affecting the course of posttraumatic stress disorder (PTSD) are poorly understood. As part of a larger study on characterizing exposure to herbicides in Vietnam, the authors investigated this issue in a random sample of 1,377 American Legionnaires who had served in Southeast Asia during the Vietnam War and were followed over a 14-year period. High combat exposure, perceived negative community attitudes at homecoming, minority race, depression symptoms at Time 1, and more anger at Time 1 predicted a more chronic course. Community involvement at Time 1 was protective and associated with decreased risk at Time 2. Discomfort in disclosing Vietnam experiences was associated with an increased risk for developing PTSD but did not predict its course. Combat exposure predicted PTSD course more strongly than any other risk factor. Findings suggest recovery from PTSD is significantly influenced by perceived social support. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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This research focuses on the spatial economics of geothermal district energy (DE) systems that distribute hot fluids through a pipeline network to multiple thermal customers. We argue here that DE is held back by uncertainty about its economic feasibility when implemented in real places. DE works best with high urban densities, but in the US the best geothermal resources are in the less-populated west. Economic geography theory suggests that the optimal size of a DE firm's service area should depend on the trade-off between the economies of scale inherent in a large service area and the greater network development costs and heat loss involved in serving a large area. The HEATMAP© software program developed by Washington State University was used to study the feasibility of numerous scenarios for a proposed DE system in Mammoth Lakes, California. Results indicate that the core area of the town is large enough, dense enough, and in close enough proximity to the resource for profitable DE development. Proposed ski village developments would increase the thermal load density and significantly enhance its ability to remain competitive with other fuels, even in pessimistic sensitivity analyses regarding geothermal heat input costs, public participation, and retro-fitting costs. 相似文献
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Sandra Aparecida de Assis Pedro Fernandes Bruno Sommer Ferreira Joaquim MS Cabral Olga Maria Mascarenhas Faria Oliveira 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(3):277-280
A partially purified extract of pectinmethylesterase (PME) from acerola fruit was immobilized on various supports: glass, celite, chrysotile, agarose, concanavalin A Sepharose 4B, egg shell, polyacrylamide and gelatin. In addition, reticulation with glutaraldehyde was assessed, as well as the use of gelatin in the presence of celite, glass and silica. The highest immobilization yields were obtained when the pectinmethylesterase was immobilized in concanavalin A Sepharose 4B (81.7%) and in gelatin‐water (78.0%). Copyright © 2004 Society of Chemical Industry 相似文献
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The effect of rapid solidification on the corrosion behaviour in aerated 0.001 M NaCl solution of Mg-Al alloys containing 9.6 to 23.4wt% AI has been investigated in comparison with chill-cast material. Polarization studies show that rapid solidification decreases corrosion current by up to two orders of magnitude corresponding to a corrosion rate of 6 to 11 mil y–1. Increasing the aluminium content in solid solution by rapid solidification gave rise to a steep increase in pitting potential between 10 and 23 wt% Al and resulted in development of an anodic plateau at 30Acm–2 attributable to magnesium depletion for the alloy surface and formation of a protective film. Chemical analysis of the electrolyte as a function of dissolution time for the rapidly solidified material indicated that initially only magnesium dissolved and that this dissolution of magnesium ceased within 2 to 5 min. The results indicate the formation of an aluminium-enriched interdiffusion zone at the surface underlying a more stable surface oxide than for ingot-processed Mg-Al-based alloys. 相似文献
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F. Sommer 《Journal of Alloys and Compounds》1995,220(1-2):174-178
Trends in the dependences on temperature and concentration of experimentally determined heat capacities of liquid and undercooled liquid metals and alloys are discussed. A new adiabatic calorimeter for determining the heat capacity of liquid alloys up to 1500 K is described. The ability of several approximations and models to describe the different characteristics of the heat capacity of liquid and supercooled liquid metals and alloys is demonstrated. 相似文献