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探讨高温环境下运动中，口服咖啡因对男大学生运动员运动中唾液分泌型免疫球蛋白A（sIgA）和溶菌酶（lysozyme，LZM）的影响。采用实验研究方法，以13名男性耐力性项目大学生运动员为研究对象。每名研究对象在温度为33℃、相对湿度为65%的实验室完成两次实验（咖啡因运动实验和对照运动实验）。每次实验中，采集运动前60 min、运动前即刻、运动20 min、运动结束即刻的唾液样本，测定唾液sIgA、LZM的浓度。实验结果显示，口服咖啡因对高温环境下耐力大学生运动员运动中唾液sIgA无影响，但会降低唾液LZM水平，高温环境、中等强度运动使男耐力大学生运动员唾液sIgA和LZM的水平升高。 相似文献
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Anne Focke Sina Spancken Christian Stockinger Benjamin Thürer Thorsten Stein 《European Journal of Sport Science》2016,16(7):787-793
Benefits of bilateral practice both for the non-dominant and for the dominant body side have been shown in several studies. Thereby, most of the studies included movement tasks of the upper extremity or investigated sports games in which the ability of acting bilaterally is an essential basis for success and, thus, a bilateral practice is reasonable anyway. Individual unilaterally performed sports including movement tasks of the lower extremity are rarely investigated. Therefore, the aim of our study was to test if contralateral transfer due to bilateral practice can be found in an unilaterally performed sport including the lower extremity. We trained and tested 61 adolescent athletes in long jump to compare the jumping performance of the dominant leg after a 12-week practice period between two groups: a bilateral practice group that practiced specific long jump exercises with both the dominant and non-dominant leg and an unilateral practice group that practiced specific long jump exercises only with the dominant leg. Results showed a superior effect of bilateral practice compared to unilateral practice regarding the jumping performance of the dominant leg. The performance increase at post-test and retention-test for the dominant limb was significantly higher for the bilateral practice group (pre-to-post: 5.2%, pre-to-retention: 7.4%) compared to the unilateral practice group (pre-to-post: 3.4%, pre-to-retention: 4.5%). Thus, bilateral practice should be established in the early practice programmes of track and field athletes to improve the performance of the dominant take-off leg. 相似文献
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Eric Sanchez Réjane Monod-Ansaldi Caroline Vincent Sina Safadi-Katouzian 《Education and Information Technologies》2017,22(6):2805-2824
This paper draws on an empirical work dedicated to discussing a theoretical model for design-based research. The context of our study is a research project for the design, the implementation and the analysis of Insectophagia, a digital role-play game implemented in secondary schools. The model presented in this paper aims at conceptualizing researchers’ and practitioners’ relationships with the notion that knowledge development takes place at a meta-didactical level when the participants develop a shared practice and a shared discourse on practice (a common praxeology). This is done through collaboration and teacher-centered design of innovative learning settings. This model emerges from a double approach: (1) a literature review on collaborative research in education and, (2) an analysis of the verbal interactions of practitioners and researchers involved in the project. The study emphasizes the development of knowledge among participants. It also emphasizes the importance of knowledge brokering for filling the gap between research and practice and thus, for the adoption of digital technology by practitioners. 相似文献
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发展性阅读障碍亚类型的研究 总被引：2，自引：0，他引：2
发展性阅读障碍是关系人类健康和发展的重要课题。多年来研究者试图寻找这个群体中发生困难的真正原因,希望从根本上解决阅读落后问题和消除阅读障碍。但是研究者发现阅读障碍群体内部具有很大的变异性。文章在简介了当今具有代表性的两种流派对阅读障碍原因的解释和相应的研究证据后,着重阐述了阅读障碍的亚类型的发展历史、研究者对亚类型的划分以及不同亚类型在语言技能上、一般感知能力和生理机制方面的差异,并且阐述了亚类型研究对阅读障碍早期预测的作用,为根本消除阅读障碍提供了新的视角。 相似文献
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Monotonic triaxial experiments to evaluate steady-state and liquefaction susceptibility of Babolsar sand 总被引：1，自引：0，他引：1
In this study, drained and undrained triaxial tests under isotropic and anisotropic consolidations were conducted on reconstituted samples of Babolsar sand, which underlies a densely populated, seismic region of the southern coast of the Caspian Sea, Mazandaran, Iran. It was demonstrated that the sand experienced all possible states of liquefiable soil： flow failure, limited flow, and dilation. The steady-state and flow liquefaction lines of this sand were presented and compared with previously tested sands. It is shown that the initial stress anisotropy can affect the potential of volume change and pore pressure generation. The steady-state line （SSL）, however, remains identical for the isotropically and anisotropically consolidated specimens under drained and undrained conditions. The tests data were then analyzed in order to investigate the liquefaction susceptibility of this sand in terms of parameters such as the state parameter, relative state parameter index, and lateral earth pressure ratio at failure. 相似文献
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Retirement is viewed as a passage that can result in psychological, physiological, and economic problems among some retirees. Adequate preparation for retirement through preretirement education, as practiced in the Western-European societies, has been found to ease transition into retirement and adjustment in retirement. Preretirement education is a relatively new practice in some organizations in Nigeria; hence, little investigation has been conducted to examine the attitudes of Nigerians toward it. Therefore, this study attempted to investigate the attitudes of Nigerian bankers toward retirement in general and preretirement education in particular. Respondents included senior members (n = 48) and middle-level workers (n = 60). There were more males (79.6%) than females (20.4%). More than half were over 40 years of age. A summary of data based on questionnaire administration reveal that retirement on its own is not as traumatic as generally thought. Respondents looked favorably toward retirement, and identified potential advantages of preretirement education. Therefore, it is recommended that employers consider preretirement education as the rule rather than the exception as currently being practiced in Nigeria. 相似文献
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Seyed Sahand SEBTI Mohammad MASTIANI Hooshyar MIRZAEI Abdolrahman DADVAND Sina KASHANI Seyed Amir HOSSEINI 《浙江大学学报(A卷英文版)》2013,14(5):307-316
A comprehensive numerical study was conducted to investigate heat transfer enhancement during the melting process in a 2D square cavity through dispersion of nanoparticles. A paraffin-based nanofluid containing various volume fractions of Cu was applied. The governing equations were solved on a non-uniform mesh using a pressure-based finite volume method with an enthalpy porosity technique to trace the solid-liquid interface. The effects of nanoparticle dispersion in a pure fluid and of some significant parameters, namely nanoparticle volume fraction, cavity size and hot wall temperature, on the fluid flow, heat transfer features and melting time were studied. The results are presented in terms of temperature and velocity profiles, streamlines, isotherms, moving interface position, solid fraction and dimensionless heat flux. The suspended nanoparticles caused an increase in thermal conductivity of nano-enhanced phase change material (NEPCM) compared to conventional PCM, resulting in heat transfer enhancement and a higher melting rate. In addition, the nanofluid heat transfer rate increased and the melting time decreased as the volume fraction of nanoparticles increased. The higher temperature difference between the melting temperature and the hot wall temperature expedited the melting process of NEPCM. 相似文献