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81.
82.
Wayne S. Walker Josef M. Kellndorfer Michael Hoppus 《Remote sensing of environment》2007,109(4):482-499
Exploiting synergies afforded by a host of recently available national-scale data sets derived from interferometric synthetic aperture radar (InSAR) and passive optical remote sensing, this paper describes the development of a novel empirical approach for the provision of regional- to continental-scale estimates of vegetation canopy height. Supported by data from the 2000 Shuttle Radar Topography Mission (SRTM), the National Elevation Dataset (NED), the LANDFIRE project, and the National Land Cover Database (NLCD) 2001, this paper describes a data fusion and modeling strategy for developing the first-ever high-resolution map of canopy height for the conterminous U.S. The approach was tested as part of a prototype study spanning some 62,000 km2 in central Utah (NLCD mapping zone 16). A mapping strategy based on object-oriented image analysis and tree-based regression techniques is employed. Empirical model development is driven by a database of height metrics obtained from an extensive field plot network administered by the USDA Forest Service-Forest Inventory and Analysis (FIA) program. Based on data from 508 FIA field plots, an average absolute height error of 2.1 m (r = 0.88) was achieved for the prototype mapping zone. 相似文献
83.
84.
A method which was developed to compare the stress–strain properties of three types of thin-walled, commercially pure titanium tubes is presented. The tubes were of types intended for use in large heat-exchanger applications and were to be subjected to significant plastic deformation during subsequent assembly processes. It had been anticipated that small differences in chemical composition and tube-drawing treatment would produce quite different characteristics. It is known that the properties of titanium can exhibit considerable degrees of anisotropy, especially for wrought products; although axial properties of the materials could be evaluated using standard test equipment and procedures, a novel testing system had to be designed to allow the circumferential properties to be assessed. Significant differences between tube types were observed and anisotropic material behaviour was apparent. 相似文献
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The Nordstrom-Robinson code is algebraic-geometric 总被引:1,自引:0,他引:1
Walker J.L. 《IEEE transactions on information theory / Professional Technical Group on Information Theory》1997,43(5):1588-1593
The techniques of algebraic geometry have been widely and successfully applied to the study of linear codes over finite fields since the early 1980s. There has also been an increased interest in the study of linear codes over finite rings. In a previous paper, we combined these two approaches to coding theory by introducing and studying algebraic-geometric codes over rings. We show that the Nordstrom-Robinson code is the image under the Gray mapping of an algebraic-geometric code over Z/4Z 相似文献
88.
DF Zatzick DS Weiss CR Marmar TJ Metzler K Wells JM Golding A Stewart WE Schlenger WS Browner 《Canadian Metallurgical Quarterly》1997,162(10):661-665
OBJECTIVE: This investigation assessed whether current post-traumatic stress disorder (PTSD) was associated with impaired functioning in a nationally representative sample of female Vietnam veterans. METHODS: Logistic models were used to determine the association between PTSD and outcome while adjusting for demographic characteristics and medical and psychiatric co-morbidities. RESULTS: PTSD was associated with significantly elevated odds of poorer functioning in five of the six outcome domains; only the association between perpetration of violence in the past year and PTSD did not achieve statistical significance. After adjusting for demographics and medical and psychiatric co-morbidities, PTSD remained associated with significantly elevated odds of bed days, poorer physical health, and currently not working. CONCLUSIONS: Among female Vietnam veterans PTSD is associated with a broad profile of functional impairment. The significantly increased odds of impaired functioning and diminished quality of life suggest that PTSD may be the core problem of the set of problems afflicting female Vietnam veterans. 相似文献
89.
Pharmacologic profile of survivors of acute myocardial infarction at United States academic hospitals 总被引:1,自引:0,他引:1
BG Phillips JM Yim EJ Brown N Bittar TJ Hoon C Celestin PH Vlasses JL Bauman 《Canadian Metallurgical Quarterly》1996,131(5):872-878
Optimal drug therapy for patients with acute myocardial infarction (AMI) is well described in the medical literature. However, data on the actual pharmacologic management of patients surviving AMI at academic hospitals is unavailable. The purpose of this study was to document treatment profiles in 500 patients surviving AMI at 12 academic hospitals in the United States. These profiles were compared with established guidelines and were evaluated for trends. Overall, thrombolytics (streptokinase > or = tissue-type plasminogen activator) were administered in 29% of the patients, with a greater proportion of patients receiving beta-blockers than calcium channel antagonists in the initial 72 hours (61% vs 40%; p < 0.005) and at discharge (51% vs 35%; p < 0.005). Further, women were less likely than men to receive thrombolytic therapy (odds ratio [OR] = 0.61; confidence interval [CI], 0.54 to 0.69) or beta-blocker therapy within the first 72 hours (OR = 0.61; CI, 0.55 to 0.67) or at hospital discharge (OR = 0.53; CI, 0.48 to 0.58). Overall, improvements could still be made in the number of patients who receive thrombolytic and acute and chronic beta-blocker therapies after AMI, particularly in women. Changes in treatment profiles may be a reflection of the publication of large clinical trials. 相似文献
90.
MG Beconi-Barker RE Hornish TJ Vidmar KJ Dame SA Brown 《Canadian Metallurgical Quarterly》1996,19(3):192-199
Coccidioides immitis, the primary pathogenic fungus that causes coccidioidomycosis, is most commonly found in the deserts of the southwestern United States and Central and South America. During the early 1990s, the incidence of coccidioidomycosis in California increased dramatically. Even though most infections are subclinical or self-limited, the outbreak is estimated to have cost more than $66 million in direct medical expenses and time lost from work in Kern County, California, alone. In addition to the financial loss, this pathogen causes serious and life-threatening disseminated infections, especially among the immunosuppressed, including AIDS patients. This article discusses factors that may be responsible for the increased incidence of coccidioidomycosis (e.g., climatic and demographic changes and the clinical problems of coccidioidomycosis in the immunocompromised) and new approaches to therapy and prevention. 相似文献