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31.
汗水皮肤上蒸发会降低体温,但是由于衣服吸附湿气,反而使体温升高,让人出更多汗为了解决这个问题,服装生产商向运动服市场推出具有“控制湿气”功能的面料,它可以通过毛细管作用将汗液带走,因此衣服很容易干,这是第一批即将推出的高科技面料。 相似文献
32.
Gavin Moir Ross Sanders Chris Button Mark Glaister 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(3):285-300
The purpose of this study was to assess the effect of periodized resistance training on accelerative sprint performance. Sixteen physically active men participated in a randomized controlled study. An experimental group (n = 10) completed an 8-week periodized resistance training intervention, while a control group (n = 6) did not train. Pre- and post-training measures of 20-m straight-line sprint time, including a 10-m split, maximum strength, and explosive strength, were recorded. Flight time, stance time, stride length, and stride frequency were quantified from digitized video recordings of the first three strides of the 20-m sprint. Resistance training resulted in significant increases in maximum strength (parallel back squat: 19%) and explosive strength (6–10%). However, both groups increased 0–10 m sprint times (experimental group = 6%; control group = 3%) while 10–20 m times were reduced (experimental group = 7%; control group = 4%), highlighting the mechanical differences between the distinct sprint phases. The change during the 0–10 m interval was accompanied by a reduction in stride frequency during the first three strides. Strength coaches should be aware that the potential benefits of increased muscular strength during short sprints are likely to be affected by mechanical specificity and that improvements in sprinting performance may not occur immediately after a period of resistance training. 相似文献
33.
We identified the perceptual–cognitive skills and player history variables that differentiate players selected or not selected into an elite youth football (i.e. soccer) programme in Australia. A sample of elite youth male football players (n?=?127) completed an adapted participation history questionnaire and video-based assessments of perceptual–cognitive skills. Following data collection, 22 of these players were offered a full-time scholarship for enrolment at an elite player residential programme. Participants selected for the scholarship programme recorded superior performance on the combined perceptual–cognitive skills tests compared to the non-selected group. There were no significant between group differences on the player history variables. Stepwise discriminant function analysis identified four predictor variables that resulted in the best categorization of selected and non-selected players (i.e. recent match-play performance, region, number of other sports participated, combined perceptual–cognitive performance). The effectiveness of the discriminant function is reflected by 93.7% of players being correctly classified, with the four variables accounting for 57.6% of the variance. Our discriminating model for selection may provide a greater understanding of the factors that influence elite youth talent selection and identification. 相似文献
34.
Mark Elizabeth Grabe 《Critical Studies in Media Communication》2013,30(3):311-328
The prevalence of verbal and physical aggression on daytime television talk shows has earned this genre the designation of “confrontainment.” In recent times academics, politicians, clergy, and media critics have frequently and publicly expressed their concern about the violation of moral values featured on the “The Jerry Springer Show.” On the other hand, sociologists in the functionalist tradition argue that commonly held moral values must be violated and the villains publicly punished for their transgressions to mark and reinforce moral boundaries. The goal of the study reported here was to assess the potential of “The Jerry Springer Show” for fulfilling these social maintenance functions. A content analysis of 100 episodes of the show over an eight-month period revealed that deviance from traditional family values is frequently featured on the show but that the studio audience and Jerry Springer played active roles in the public degradation of these transgressions, casting the show in a morally conservative light. 相似文献
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Ordinary and thermal diffusion of moisture in activated alumina are investigated using a new diffusion cell design and scheme of analysis reported earlier. The specific form of the mass flux equation has a pronounced effect on the magnitude of the associated thermal diffusion ratio. In the case of activated alumina-moist air, if a partial pressure gradient is used, then the thermal diffusion term is small if not zero.Free, Knudsen and surface diffusion all play a part in the diffusion through activated alumina. However, surface diffusion makes the major contribution and for this reason the model in this case can be simplified to a two parameter surface model.The activation energy for surface diffusion is constant and is approximately equal to the mean isosteric heat of absorption. In addition, mean pore radius, turtuosity, and other physical constants are computed from the least square fit of experimental data. Furthermore, the model is theoretically consistent over the entire concentration range (0≦ CA ≦ CAsat).A new fact about activated alumina (Grade F1) it that it does not transfer moisture in a nonisothermal condition so long as the partial pressures of moisture on the two sides of the pellet are the same. There appears to be no previous report of this fact in the periodical literature. 相似文献
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38.
Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h?1 wearing a backpack of either 0 (LC0), 10 (LC10), 15 (LC15) or 20?kg (LC20). Inspiratory (PImax) and expiratory (PEmax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean PImax and PEmax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?.05) with changes not different between trials (p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters. 相似文献
39.
ABSTRACT: After a brief discussion of the concept of love and contemporary attitudes towards it, the article examines previously unpublished findings about children's ways of thinking about love, using evidence drawn from a research project on the developing sexual values of 9 and 10 year-old children. Love features extensively in their discussions and appears central to their worldview. They are aware of some of the complexities of love, and would value opportunities to discuss it further. The article concludes with a discussion of current inadequacies and future possibilities in schools' provision. 相似文献
40.