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31.
Athens sits in a basin approximately 450 km2 in area, surrounded by mountains and open sea. Anthropogenic emissions in conjunction with the topographical and meteorological conditions can result in high air pollution within the city. The pollutants of concern for athletes competing in Athens 2004 appear to be nitrogen dioxide (NO2), ozone and particulate (PM10) pollution. Exposure to elevated ozone concentrations has been reported to give rise to symptoms that include cough, chest pain, difficulty in breathing, headache, eye irritation and a decrease in forced expiratory volume in one second. All of these effects are likely to impact upon performance, and several studies of cyclists suggest this to be the case. In contrast, the impact of ambient concentrations of NO2 appears to be negligible on normal activities, but at high exercise intensities the impact remains unclear. The use of currently available information and models to predict the effect of ozone and other pollutants on elite athletes is problematical, since such models are based upon significantly lower ventilation rates than those achieved by some elite athletes. In addition, it is already known that the response to ozone can vary somewhat between individuals. Since the individuals who will be competing in Athens are physiologically very different to the participants in most published studies, it is difficult to predict individual responses. There is some evidence to indicate that adaptation to the adverse health and performance effects of ozone can occur, so that performance is partially recovered on re-exposure. The adaptation is not seen in all studies and appears to be dependent on several factors, including the initial sensitivity of the individual to ozone. Antioxidant supplementation has also been shown in some studies to partially ameliorate the adverse effects of ozone by counteracting the oxidative stress mechanism associated with this pollutant. Whether this transfers to performance enhancement per se remains unclear at present. Additional research is required to gain a sound understanding of the effects of a complex mixed air pollution exposure on the pulmonary function and performance of athletes exercising at high work intensities. 相似文献
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议程设置理论与后大众媒体时代的民意研究 总被引:4,自引:0,他引:4
关于媒体与民意的理论大部分提出于 1 93 0到 1 980年之间 ,这是一个仅仅拥有传统信息选择方式的时代。麦库姆斯和肖 (1 972 )最初提出议程设置理论时 ,用北卡罗莱纳州的教堂山 (ChapelHill)社区作为研究对象 ,而现在那里的媒介使用情况也已经发生了巨变。当我们迎来议程设置理论提出 3 0周年的时候 ,教堂山的受众现在面临的信息选择令人惊叹。在 2 0世纪 90年代 ,肖提出 ,美国的大众媒介已经经历了“兴和衰”(riseandfall)。肖认为 ,大众媒体时代结束于 2 0世纪 80年代。议程设置研究是否能像之前的 3 0年那样 ,继续开展下去 ?当受众使用着上百个信息来源时 ,议程设置和民意研究会产生何种变化 ?这是本文将要回答的问题 相似文献
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This paper describes a small‐scale study of what the authors describe as the ecosystemic approach to changing chronic problem behaviour. The study was undertaken with a group of twelve Leicestershire primary teachers. The technique is briefly described and then teachers' responses to it and its effectiveness are discussed. Four case study examples are presented and finally its potential is considered. Although in this case the work was undertaken with primary teachers, this is an approach which could also be useful at secondary level. 相似文献
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Keith Shaw 《British journal of educational technology : journal of the Council for Educational Technology》2008,39(2):319-323
This paper compares and contrasts the use of AI principles in industrial training with more normal computer‐based training (CBT) approaches. A number of applications of CBT are illustrated (for example simulations, tutorial presentations, fault diagnosis, management games, industrial relations exercises) and compared with an alternative approach using AI. An evaluation of the relative merits of the two approaches will be given. Existing CBT packages are used to illustrate the points raised and the emphasis of the arguments will be on the effectiveness of AI and CBT in terms of both cost and learning. The position of AI applications within CBT is discussed, as is the task of getting started in applying these techniques. 相似文献
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Based on quantitative data from the Norwegian Statistisk Sentralbyrå (Statistics Norway) study of Mosjon, Friluftsliv og Kulturaktiviteter, this paper explores trends in Norwegians' participation in sports, with a focus on young people. Norway boasts particularly high levels of sports participation as well as sports club membership and young Norwegians are the quintessential sporting omnivores. Among other things, the Statistics Norway study reveals substantial increases in participation (among young people and females especially) during the period 1997–2007, a shift in the peak of participation to the late teenage years, a relatively high level of lifelong participants, a re-bound effect in the post-child rearing years and a growth in lifestyle sports. Young Norwegians grow up in a socio-economic context of relative equality between the sexes and high standards of living. An abundance of natural and artificial outdoor and indoor sporting facilities alongside a well-established voluntary sports club sector and an elementary school system that emphasizes physical exercise and recreation, as well as high levels of parental involvement, add to the favourable socio-economic conditions to create seemingly optimal circumstances for sports participation. All these reinforce the sporting and physical recreation cultures deeply embedded in Norwegian society and embodied by the very many middle-class parents in a country which, for the time being at least, remains relatively young in demographic terms. In terms of lessons to be learned for policy towards sports and physical education beyond Norway, there may be grounds for some optimism around parental involvement in children's sport as well as the potential appeal of lifestyle sports. That said, it is likely to be the greater socio-economic equalities in Scandinavian countries such as Norway that make them unrealistic benchmarks for sports participation elsewhere. 相似文献