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191.
192.
新时期中外高校体育教育思想发展趋势比较分析 总被引:3,自引:0,他引:3
本文介绍了德国和俄罗斯学校在体育发展的多方向、多功能的趋势,分析了我国高校体育教育的现状,从体育与健康课程整合的方面,提出高校体育应借鉴国外体育教育强国的思想观念,强调体育教改应重视学生身心的全面成长,贯穿“个体化、专项化、社会化”的思想。 相似文献
193.
Qin Shao Machelle D. Wilson Christopher S. Romanek Keith A. Hobson 《Environmental and Ecological Statistics》2004,11(3):323-337
A temporal record of environmental conditions is often contained within accretionary biological tissue. These records can provide knowledge of the environmental conditions that existed at the time the tissue was formed. In this study, we look at trace element concentrations and isotopic ratios of carbon and nitrogen as contained in baleen from bowhead whales in the eastern and western Arctic Ocean. Time series techniques, including maximum likelihood method and likelihood ratio tests, are applied to analysis of data and inference about their mean structures. 相似文献
194.
网络环境下信息检索语言的研究进展 总被引:1,自引:0,他引:1
本文通过对近年来国内外对网络环境下信息检索语言理论及应用性成果的研究,分析了检索语言的研究进展,并尝试性地对网络环境下这一领域的发展趋势进行了展望。 相似文献
195.
本文通过对近年来国内外对网络环境下信息检索语言理论及应用性成果的研究,分析了检索语言的研究进展,并尝试性地对网络环境下这一领域的发展趋势进行了展望。 相似文献
196.
197.
The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx^- -N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx^- -N concentration in the anoxic zone(SNo) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when SNO reached about 2 mg/L. Through keeping SNO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No. 1 (ASM No. 1), a simplified mathematical model of external carbon dosage was developed, Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances. 相似文献
198.
厦门西港表层沉积物中有机氯化合物的污染特征及变化趋势 总被引:13,自引:3,他引:13
利用GC-ECD对厦门西港1998年7月取得的8个站位表层沉积物中的18种有机氯农药(HCHs,DDTs)等和12种多氯联苯(PCBs)进行分析。其中有机氯农药的浓度范围ND(未检测出)-0.58ng/g(其中HCHs和DDTs的含量分别为ND-0.14ng/gND-0.06ng/g),多氯联苯的浓度为ND-0.32ng/g,与1986、1993年的厦门西港的分析结果相比较,污染程度明显降低;说明近年来的厦门的有机污染得到逐步控制,也与有机物随时间推移逐渐详解有关,分析表明多氯联苯和有机氯农药在厦门西港有着相似的分布特征。 相似文献
199.
B.G. Arends J.H. Baard H.M. Ten Brink 《Atmospheric environment (Oxford, England : 1994)》1997,31(24):4063-4072
A trend analysis of the sulphate concentration in Europe in the summer half-year was performed. Data from various measuring networks were analysed, but only stations with quality assured sampling methods and a record of more than 10 years were included in the study. 1978 served as the reference year for the trend, because in that year most stations started operation. The relatively dense network in Belgium provided the most valuable data, as evidenced by the fact that two sites at a distance of only 10 km apart correlated better than 95% over a month. The two sites also show a correlation of better than 90% over a season with two other stations at distances of 45 and 95 km. The relative decrease in summer-sulphate at the four stations in Belgium, as analysed by linear regression, was 3.3% per year which corresponds to an absolute decrease of 0.42 μgm−3 per year. In the Netherlands the average yearly decrease in summer-sulphate at two stations was 3.5% (−0.34 μgm−3). In other countries stations were further apart or only a single site wits in use, which limits the representativeness of the data. In northwestern Germany, a region with several monitoring stations, a yearly averaged decrease of 3.0% occurred. The lower absolute decrease (0.25 μgm−3) per year compared to that in the two neighbouring countries reflects the lower summer-time sulphate concentrations. In the remainder of Germany the average decrease was 1.6%. In South-Scandinavia the yearly relative decrease at two sites was 2.6% (0.13 μgm−3 absolute). There was no significant trend in the U.K. Al the Polish station the levels increased, it decreased at the Hungarian and Austrian station and remained constant at the Czechoslovakian site. Reasons for omission of the data from France from the trend analysis are discussed. 相似文献
200.
Christel Faes Marc Aerts Helena Geys Geert Molenberghs Lieven Declerck 《Environmental and Ecological Statistics》2004,11(3):305-322
Developmental toxicity studies are widely used to investigate the potential risk of environmental hazards. In dose–response experiments, subjects are randomly allocated to groups receiving various dose levels. Tests for trend are then often applied to assess possible dose effects. Recent techniques for risk assessment in this area are based on fitting dose–response models. The complexity of such studies implies a number of non-trivial challenges for model development and the construction of dose-related trend tests, including the hierarchical structure of the data, litter effects inducing extra variation, the functional form of the dose–response curve, the adverse event at dam or at fetus level, the inference paradigm, etc. The purpose of this paper is to propose a Bayesian trend test based on a non-linear power model for the dose effect and using an appropriate model for clustered binary data. Our work is motivated by the analysis of developmental toxicity studies, in which the offspring of exposed and control rodents are examined for defects. Simulations show the performance of the method over a number of samples generated under typical experimental conditions. 相似文献