Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners?     

J. Santos-Concejero  N. Tam  D. R. Coetzee  J. Oliván  T. D. Noakes  R. Tucker 《Journal of sports sciences》2017,35(6):531-538

The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h^?1 and 20 km ·h^?1). VO₂ and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg^?1· km^?1 at 12 km· h^?1 and 184.8 ± 9.9 ml· kg^?1· km^?1 at 20 km· h^?1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg^?1·km^?1 and 0.93 ± 0.07 kcal· kg^?1· km^?1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h^?1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners.  相似文献   

The majority influence on interminority attitudes: The secondary transfer effect of positive and negative contact     

《Int J Intercult Relat》2016

Among minority members, positive contact with the majority was previously found to improve not only the attitudes toward the majority but also the attitudes toward minority outgroups (the secondary transfer effect; STE). However, the roles of negative intergroup contact and minority groups’ social status in the STE have not been yet examined. Therefore, in the present study, we investigated the association between both positive and negative contact with the national majority group (Finns) and mutual attitudes among high-status Estonian (n = 171) and low-status Russian (n = 180) immigrants in Finland. Two mediators of the STE were tested: attitudes toward the majority (attitude generalization) and public collective self-esteem (diagonal hostility). While positive and negative STEs emerging via attitude generalization were expected to occur among both immigrant groups, the mediating effect of public collective self-esteem was assumed only for members of the low-status group. In both immigrant groups, the relationship between positive contact with the majority group and attitudes toward the other immigrant group was positive and indirect through more favorable attitudes toward majority group members. The same mechanism characterized negative contact, where the indirect effect was mediated by less positive attitudes toward Finns. As predicted, public collective self-esteem mediated the effects of positive and negative contact with majority group members on attitudes toward the other minority only among low-status Russian immigrants. The results call for the acknowledgement of different mechanisms explaining the STE among minority groups enjoying different social statuses in host society.  相似文献   

The density of social networks moderates effects of intergroup contact     

《Int J Intercult Relat》2016

This study tests how the density of the social network in which intergroup contact takes place might affect the extent to which contact improves intergroup attitudes. Having contact with more outgroup members in dense social networks, in which everybody knows each other, may reinforce contact's positive effect. In this case, outgroup contact is shared with ingroup members, which suggests positive ingroup norms toward the outgroup. Alternatively, more contact in denser networks may improve intergroup attitudes less because density may increase subtyping or reduce the salience of ethnic group memberships. These competing hypotheses are tested among white American adults in a nonprobability online sample (N = 305) and in a representative national sample (N = 1270). In both studies, contact is associated with more positive attitudes toward racial outgroups but the positive contact effect is weakened if that contact takes place in a denser social network.  相似文献   

English Proficiency,Identity, Anxiety,and Intergroup Attitudes: US Americans’ Perceptions of Chinese     

Makiko Imamura  Racheal A. Ruble  Yan Bing Zhang 《Journal of Intercultural Communication Research》2016,45(6):526-539

Guided by the Common Ingroup Identity Model and Berry’s acculturation framework, this study examined the roles that perceptions of language proficiency, cultural identity, and communication anxiety had on intergroup attitudes and stereotypes in the American–Chinese contact context. Serial mediation analyses with 10,000 bootstrap samples revealed that perceived English proficiency of a Chinese contact had significant indirect effects on affective and behavioral attitudes toward Chinese through American participants’ perceptions of their contact’s host and home culture identification and communication anxiety. Perceived English proficiency had an indirect effect only on positive stereotypes through the Chinese contact’s perceived identification with home culture.  相似文献   

Initial Communication with and Attitudes toward International Students: Testing the Mediating Effects of Friendship Formation Variables     

Ning Liu  Yan Bing Zhang  Weston T. Wiebe 《Journal of Intercultural Communication Research》2017,46(4):330-345

From the theoretical perspectives of intergroup contact, predicted outcome value (POV), and similarity-attraction, this study examined U.S. host nationals’ (N = 342) communicative behaviours in a recent initial encounter with an international student and attitudes toward the student’s cultural group as a whole. Testing of two models indicated the significant sequential mediator effects of perceived similarity-social attraction and POV-social attraction between communication variables (e.g. amount of communication exchange in both models, self-disclosure in model 1, and information seeking in model 2), and intergroup attitudes (e.g. behavioural attitudes). Findings in general demonstrated that contact effects in the intercultural context varied according to specific measures of communication, the mediating mechanisms, and intergroup attitudes.  相似文献   

论强国富民离不开美育   总被引：2，自引：0，他引：2  

阎丽杰 《沈阳教育学院学报》2005,7(4):37-39

美育有助于提高生产力.从社会的发展趋势来看,美育和科学技术愈来愈紧密地融合.美育和科学技术融合有深厚的理论基础.培养人才离不开美育,美育和创造性人才有内在的心理联系.将美育真正融入学校、家庭、社会,全面提升学生素质是切实可行的.  相似文献   

严复与袁世凯关系释论   总被引：2，自引：0，他引：2  

李喜所  贾菁菁 《天津师范大学学报(社会科学版)》2006,(4):59-64

关于严复和袁世凯的关系,学界关注很少。事实上,严复和袁世凯交往的二十多年,经历了戊戌变法、辛亥革命和民初政坛风云的起伏,严袁之间的友谊和纷争,深刻反映了那时社会文化的变迁,也透视出严复的政治追求及其对袁世凯的整体认识。严复倾心袁世凯,既是个人好恶,更有着深刻的社会政治背景。  相似文献   

Simulation of Fragment Impact on Multi-Layer Targets Using Contact Method     

CRAWFORD John E 《天津大学学报(英文版)》2006,12(Z1)

Cased explosives generate highly energetic fragments as their casing breaks up. Due to the complexity of casing fragment related behavior such as embedment, perforation and ricochet, it may be insufficient to use equivalent triangular pressure loading in fragment impact simulations. This simplified method may over- or under-predict the target response. Recently, a procedure using contact techniques has been proposed to overcome such difficulties. It has been shown that the new method has the inherent capability in modeling the multi-piece and multi-hit fragment impact problems in a more realistic way. To investigate the applicability of the proposed method to simulations involving multi-layer penetration, the selected problems of fragment impact on multi-layer targets are described in this paper. It is demonstrated that this method is capable of predicting the complicated multi-layer structural response caused by fragment impact and penetration. Modeling procedures and some technical issues are also discussed.  相似文献   

好氧生物处理实验的研究     

赵海霞  包南  张成禄  常宏文 《实验室研究与探索》2004,23(4):26-27,30

介绍了具有代表性的好氧生物处理的两个典型实验的方法,讨论了作为研究生阶段开设这两个实验的具体的实验内容以及最佳运行方案。  相似文献   

保险合同中违反告知义务的构成要件分析     

庄朝蓉 《四川职业技术学院学报》2003,13(2):17-19

保险合同中违反如实告知义务的构成要件是：违反如实告知义务的主体是投保人或被保险人；违反告知义务的范围仅限于保险人询问的范围；过失违反告知义务的事实应当是重要事实；投保人、被保险人违反告知义务是出于主观上的故意或过失。  相似文献