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991.
992.
体育运动对提高大学生社会适应能力的作用 总被引:1,自引:0,他引:1
体育运动的社会特性毋庸置疑是提高人的社会健康水平,同时,人在体育运动时,既要定位与合作,又存在相互竞争的现象。这对提高大学生的社会适应能力具有一定的积极意义。 相似文献
993.
浅析篮球训练和比赛中合理补水的重要性 总被引:1,自引:0,他引:1
在篮球训练和比赛中,运动员丢失大量的汗液,使机体内水、电解质平衡紊乱.因此,运动前、中、后的合理补水对保持体内水和电解质的平衡,提高耐力,延迟疲劳的出现,从而提高运动能力非常重要. 相似文献
994.
995.
A. Guala E. Biroli P. Bassini G. Botta D. Licata G. Di Cara D. Franceschini P. Franceschini 《黑龙江环境通报》2001,21(13):1146-1149
Kyphomelic dysplasia (KD) is a rare autosomal recessive entity characterized by disproportionate dwarfism with shortening and bowing of the limbs, narrow chest, 11 ribs and metaphyseal flaring. Mental development is generally normal. We report the in utero ultrasound appearances and post-mortem radiographic findings of a 22-week-old male fetus suggestive of KD. A review of 19 previously reported patients with KD is also presented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
996.
综掘工作面卸压槽防突措施试验研究 总被引:2,自引:0,他引:2
蔡成功 《中国安全科学学报》2004,14(4):83-85
通过对卸压槽防突机理的系统分析 ,研制了直接利用掘进机自身动力驱动和控制开挖连续卸压槽装置 ,进行了水平槽、两帮竖槽开挖工艺试验 ,成功地开挖出连续卸压槽 ,对卸压槽的瓦斯排放效果、有效排放半径进行了考察。试验结果表明 ,卸压槽有效地消除了激发突出的应力 ,排放了煤体中的瓦斯 ,增大了煤体抑制突出的阻力 ,很好地起到了综合防突的作用。 相似文献
997.
A model of fishing vessel accident probability 总被引:5,自引:0,他引:5
Problem: Commercial fishing is one of the least safe occupations. Method: The researchers develop a fishing vessel accident probability model for fishing areas off the northeastern United States using logit regression and daily data from 1981 to 1993. Results: The results indicate that fishing vessel accident probability declined over the study period. Higher wind speed is associated with greater accident probability. Medium-size vessels have the highest accident probability, while small vessels have the lowest. Within the study region, accident probability is lower in the southwestern section than in the northeastern section. Accidents are likely to occur closer to shore than offshore. Accident probability is lowest in spring. Impact on Industry: The probability model is an important building block in development and quantitative assessment of management mechanisms related to safety in the commercial fishing industry. 相似文献
998.
Sinaj S Stamm C Toor GS Condron LM Hendry T Di HJ Cameron KC Frossard E 《Journal of environmental quality》2002,31(1):319-330
Although phosphate phosphorus (P) is strongly sorbed in many soils, it may be quickly transported through the soil by preferential flow. Under flood irrigation, preferential flow is especially pronounced and associated solute losses may be important. Phosphorus losses induced by flood irrigation were investigated in a lysimeter study. Detailed soil chemical analyses revealed that P was very mobile in the topsoil, but the higher P-fixing capacity of the subsoil appeared to restrict P mobility. Application of a dye tracer enabled preferential flow pathways to be identified. Soil sampling according to dye staining patterns revealed that exchangeable P was significantly greater in preferential flow areas as compared with the unstained soil matrix. This could be partly attributed to the accumulation of organic carbon and P, together with enhanced leaching of Al- and Fe-oxides in the preferential flow areas, which resulted in reduced P sorption. The irrigation water caused a rapid hydrologic response by displacement of resident water from the subsoil. Despite the occurrence of preferential flow, most of the outflowing water was resident soil water and very low in P. In these soils the occurrence of preferential flow per se is not sufficient to cause large P losses even if the topsoil is rich in P. It appears that the P was retained in lower parts of the soil profile characterized by a very high P-fixing capacity. This study demonstrates the risks associated with assessing potential P losses on the basis of P mobility in the topsoil alone. 相似文献
999.
Metabolic transformation plays a major role in the mechanism of toxicity of organophosphorous (OP) pesticides. The modulation of their toxicity by oxonases and monooxygenases, alone or in combination, has been shown in mammals and fish. Very limited information exists for the identification of the metabolic factors relevant in the human toxicology of such chemicals. In this paper, we develop a simple algorithm, based on in vitro data, for the identification of fish species more susceptible to diazinon (D). Similar algorithms are likely to be applicable to other organophosphothionate (OPT) pesticides. We also report on preliminary studies on the OPT substrate specificity of human liver cytochromes P450 (CYPs): such information may be useful to understand the role of sulphoxidation in OPT toxicity to humans and to identify individuals with increased susceptibility to OPT toxicity. Studies of the mechanism of OPT toxicity may provide useful tools for a more detailed characterisation of these chemicals, with reference to the risk for the human population and to the impact on the fish species present in specific environments. 相似文献
1000.
大气中羰基化合物的研究进展 总被引:2,自引:0,他引:2
羰基化合物是大气中重要的毒性挥发性有机物.近lO年来国内外学者对大气羰基化合物进行了较多的调查和研究.文章对相关调查研究的主要发现进行了系统的综述.文献资料显示.国内的研究主要集中在北京、广州、青岛、杭州和香港.尤其是广州.在最常检测到的羰基化合物中,甲醛、乙醛和丙酮的浓度相对较高.绝大部分研究发现,羰基化合物浓度呈现市区和工业区的高于郊区或乡村的,室内的高于室外的,夏季的高于冬季的,并且有明显的日变化规律.很多研究者根据甲醛/乙醛(C1/C2)和乙醛/丙醛(C2/C3)浓度比以及不同羰基化合物间的相关性来推断羰基化合物的可能来源,这些可能来源包括汽车尾气、大气光化学反应等.但上述方法不能判断羰基化合物的准确来源及不同释放源的贡献率.作者认为,应该借助碳同位素分析方法或其他新技术来加强大气羰基化合物的释放源及其贡献率的研究.此外,大气羰基化合物在不同气候条件下的形成、反应、迁移和转化机理也值得进一步研究. 相似文献