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ELDORA/ASTRAIA机载多普勒气象雷达最近已由美国和法国大气科学研究实验室交付使用。按其设计,ELDORA/ASTRAIA雷达能对大气风暴的气流运动和降雨特性提供高分辨率测量,而地面雷达则因这些气象目标太宽,太远或快速运动不能对其进行充分的观测,本文讨论了这种雷达的测量要求和设计目标,给出了按最新气象研究外场计划测量采样的结果。  相似文献   
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Scientists and educators at Baylor College of Medicine are using space life sciences research areas as themes for middle school science and health instructional materials. This paper discusses study findings of the most recent unit, Food and Fitness, which teaches concepts related to energy and nutrition through guided inquiry. Results of a field test involving more than 750 students are reported. Use of the teaching materials resulted in significant knowledge gains by students as measured on a pre/post assessment administered by teachers. In addition, an analysis of the time spent by each teacher on each activity suggested that it is preferable to conduct all of the activities in the unit with students rather than allocating the same total amount of time on just a subset of the activities.  相似文献   
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To assess the effects of prolonged space flight on the electrophysiological properties of the heart, vectorcardiograms (VCG) were obtained on the Skylab crews at regular intervals during flight and the pre- and postflight periods. The VCG signals were telemetered from Skylab and analyzed by digital computer. Conventional 12-lead electrocardiograms were derived from the VCG signals by a lead transformation program. Standardized exercise loads were incorporated into the experiment protocol to increase the sensitivity of the VCG for effects of deconditioning and to detect susceptibility for arrhythmias. In Skylab II, 24 preflight, 21 inflight, and 19 postflight experiments were analyzed. Statistically significant inflight changes observed in two or more crew members included: decreased resting heart rate, increased QRS duration, anterior shift QRS vector, increased QRS vector magnitude, anterior shift T vector, and increased T vector magnitude. One astronaut had occasional premature ventricular contractions (PVC) during the pre- and postflight phases. He had a single episode of multiple PVC's during heavy-load exercise testing in flight. A second astronaut had no arrhythmia during pre- or inflight testing. On postflight day 21 he had multiple PVC's and salvos of ectopic ventricular beats. He has had no recurrence of the arrhythmia. With the exception of the cardiac arrhythmias, no deleterious electrophysiological changes were observed during Skylab II.  相似文献   
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We evaluated the astrobiological potential of the major classes of geologic units on Europa with respect to possible biosignatures preservation on the basis of surface geology observations. These observations are independent of any formational model and therefore provide an objective, though preliminary, evaluation. The assessment criteria include high mobility of material, surface concentration of non-ice components, relative youth, textural roughness, and environmental stability. Our review determined that, as feature classes, low-albedo smooth plains, smooth bands, and chaos hold the highest potential, primarily because of their relative young age, the emplacement of low-viscosity material, and indications of material exchange with the subsurface. Some lineaments and impact craters may be promising sites for closer study despite the comparatively lower astrobiological potential of their classes. This assessment will be expanded by multidisciplinary examination of the potential for habitability of specific features.  相似文献   
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The top priority in America's manned space flight program is the assurance of crew and vehicle safety. This priority gained greater focus during and after the Space Shuttle return-to-flight mission (STS-26). One of the interesting challenges has been to assure crew safety and adequate protection of the Space Shuttle, as a national resource, from increasingly diverse cargoes and operations. The control of hazards associated with the deployment of complex payloads and cargoes has involved many international participants. These challenges are examined in some detail along with examples of how crew safety has evolved in the manned space program and how the international partners have addressed various scenarios involving control and mitigation of potential hazards to crew and vehicle safety.  相似文献   
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PH Rampelotto 《Astrobiology》2012,12(6):529-534
The Europa Jupiter System Mission (EJSM) is the major Outer Planet Flagship Mission in preparation by NASA. Although well designed, the current EJSM concept may present problematic issues as a Flagship Mission for a long-term exploration program that will occur over the course of decades. For this reason, the present work reviews the current EJSM concept and presents a new strategy for the exploration of Europa. In this concept, the EJSM is reorganized to comprise three independent missions focused on Europa. The missions are split according to scientific goals, which together will give a complete understanding of the potential habitability of Europa, including in situ life's signal measurements. With this alternative strategy, a complete exploration of Europa would be possible in the next decades, even within a politically and economically constrained environment.  相似文献   
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