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11.
Ryuji Kawamoto Yusuke Ishige Koji Watarai Senshi Fukashiro 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):167-186
The purpose of this study was to determine primary factors that contribute to the magnitude of the maximum torsional moment on the tibia during running based on information from three‐dimensional shank kinematics and ground reaction forces. Eight male subjects were asked to run along a straight track at 5.0 m s‐1. Data were collected using two high‐speed cameras and a force platform. Each subject's left foot and tibia were modelled as a system of coupled rigid bodies. First, net axial moments acting at both ends of the tibia were calculated using inverse dynamics. Then the tibial torsional moment was determined from the quasi‐equilibrium balance of the net tibial axial moments. Our results showed considerable inter‐individual variations for the tibial torsional moment during the stance phase of running. The maximum torsional moment reflecting external rotational loading of the proximal tibia was significantly correlated with the outward tilt angle of the shank in the frontal plane (r = 0.78, p <0.05) and with the vertical force of ground reaction (r = 0.70, p <0.05). In conclusion, lowering tibial torsional loading by interventions based on the present findings may lead to the reduction of running injuries that occur in athletes’ tibiae. 相似文献
12.
The within-trial contrast hypothesis (WTC) provides a more parsimonious explanation for the phenomenon that humans and animals prefer outcomes that follow more effortful events to outcomes that follow less effortful events (Zentall, 2013). We conducted two WTC experiments with human adults. In Experiment 1, we manipulated the difficulty of a preceding event by varying the interresponse time and the limited-hold interval during differential reinforcement with a low response rate schedule, to examine the effect of effort on the preference for the subsequent stimuli. In Experiment 2, we attempted to identify the variables that had affected the results of Experiment 1, by manipulating time as the delay of reinforcement. The results showed preferences based on WTC only when participants made a high rate of incorrect responses in the preceding event, which was used as an index of the strength of individual effort. These results extend the findings of previous human WTC studies and suggest that the difficulty of a task could serve as an aversive event that affects the WTC effect. It is possible that an index based on performance in the preceding event would provide useful information for predicting the contrast effect. 相似文献
13.
西方各国之间早在文艺复兴时期就已经发展起来了自己的口语交流，而近代以前的日本与韩国还处于中华强大的中心文明的单向辐射之下。近代以来，西方尤其是美国文化取代了古代中国在东亚的位置。东亚各国没有真正走向平等的横向交流，口语沟通仍然十分匮乏。目前，这种以欧美为中心的局面正在改变。在东亚应当提倡重视周边国家的文化，提倡用口语自由交往。 相似文献
14.
锡金喜马拉雅地区是全球重要的生物多样性热点地区之一,该地区的农业生产系统最近已经被推荐作为联合国粮农组织（FAO）全球重要农业文化遗产（GIAHS）保护的候选地。在这一地区,集中体现了被称为Demazong（稻米之谷）或香格里拉（消失的地平线）的神圣景观。这个神圣的、多样性的文化景观中,当地少数民族社区利用传统的生态知识对极为丰富的农业生物多样性进行适应和管理。多样化的农业生态系统,包括位于高山地区农牧复合系统Dokpas,位于温带地区的传统的农林复合系统（如桤木-草本混交农业系统）,以及海拔较低的暖温带到亚热带农业气候区的梯田/谷地稻作系统。将富含文化多样性和生物多样性的土地利用系统与景观进行边缘化是一件十分荒谬的事情。但值得说明的是,尽管这里有着巨大的发展潜力,却长期存在着贫穷、进入市场困难、经济和生态较为脆弱等问题。
锡金喜马拉雅地区的农业是一种典型的适应性管理系统,具有重要的生态系统服务功能,提供了具有重要经济价值的多样化的农作物品种,以及适应明显垂直分异农业生态区的多用途的植物物种。在那里生活着的不同的土著社区,依然保持着传统的生态知识,以适应、监测和响应生态系统的恢复能力与生态系统的服务功能。在本文中,我们探讨了传统农业在生物多样性保护中的作用,评估了从亚热带到高原农业生态区的多样性的生态系统管理途径,分析了对于农业生态系统的社会适应性与知识基础以及传统体制在促进该地区农业生产系统通过GIAHS在地区、国家和全球水平上获得更加广泛的认可的作用。我们认为,为减轻气候变化的可能影响和应对可能的新挑战,应当采用参与式的方式对传统农业进行监测,并制定科学的政策。锡金喜马拉雅地区的传统农业被认定为全球重要农业文化遗产,将有助于促进这一传统农业系统的保护,促进边际社区的环境健康和生计的可持续性,确保该地区的可持续发展。 相似文献
15.
Iida H Kato S Sekino Y Sakai E Uchiyama T Endo H Hosono K Sakamoto Y Fujita K Yoneda M Koide T Takahashi H Tokoro C Goto A Abe Y Kobayashi N Kubota K Gotoh E Maeda S Nakajima A Inamori M 《Journal of Zhejiang University. Science. B》2012,13(1):29-34
Objective
The ideal medication for the treatment of acid-related diseases, e.g., peptic ulcers, stress-related gastric bleeding, functional dyspepsia, and gastroesophageal reflux disease, should have a rapid onset of action to promote hemostasis and relieve the symptoms. The aim of our study was to investigate the inhibitory effects on gastric acid secretion of a single oral administration of a proton pump inhibitor, omeprazole 20 mg, and an H2-receptor antagonist, roxatidine 75 mg.Methods
Ten Helicobacter pylori-negative male subjects participated in this randomized, two-way crossover study. Intragastric pH was monitored continuously for 6 h after single oral administration of omeprazole 20 mg and roxatidine 75 mg. Each administration was separated by a 7-d washout period.Results
During the 6-h study period, the average pH after administration of roxatidine was higher than that after administration of omeprazole (median: 4.45 vs. 2.65; P=0.0367). Also during the 6-h study period, a longer duration of maintenance at pH above 2, 5, and 6 was observed after administration of roxatidine 75 mg than after administration of omeprazole 20 mg (median: 90.6% vs. 55.2%, P=0.0284; 43.7% vs. 10.6%, P=0.0125; 40.3% vs. 3.3%, P=0.0125; respectively).Conclusions
In Helicobacter pylori-negative healthy male subjects, oral administration of roxatidine 75 mg increased the intragastric pH more rapidly than that of omeprazole 20 mg. 相似文献16.
Kadota K Matsuo T Hashizume K Tezuka K 《Research quarterly for exercise and sport》2006,77(3):285-295
We investigated the differences in mechanical power flow in early and late practice stages during a cyclic movement consisting of upper arm circumduction to clarify the change in mechanical energy use with skill acquisition. Seven participants practiced the task every other day until their joint angular movements conformed to those of an expert. During the practice sessions, participants' motions were digitally recorded once a week using four high-speed infrared cameras, and the joint kinematics and joint powers of the right arm were calculated. With practice, the inflow power derived from the net joint force increased at the hand, forearm, and upper arm segments by 143.1 +/- 17.2%, 57.1 +/- 7.3%, and 198.1 +/- 35.4%, respectively. In contrast, the power caused by the muscle joint moments was not significantly increased. These results suggested that participants acquired a motor pattern promoting transfer of the joint reaction forces. Results may provide some support for Bernstein's (1967) ideas that skill acquisition involves improving movement efficiency by greater use of nonmuscular forces. 相似文献
17.
Hoga K Ae M Enomoto Y Yokozawa T Fujii N 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):167-182
This study analyzed the joint torque and the mechanical energy flow in the support legs of skilled male race walkers. Twelve race walkers were videotaped using a high-speed camera at a frame rate of 250 Hz set perpendicular to the sagittal plane of motion; their ground reaction forces were measured with two force platforms. A two-dimensional, 14-segment, linked model was used to calculate the kinetics of the support leg joints. In the initial part of the support phase, the mechanical energy flowed into the thigh and shank by the torque of the large hip extensors and knee flexors. In the middle part, the mechanical energy generated by the torque of the large plantar flexors flowed to the foot and from the foot to the shank by the ankle joint force. The mechanical energy flow by the forward joint force of the support hip was significantly related to the walking speed in the final part of the support phase. Our findings suggest that race walkers in the final part of the support phase should exert the torque of the knee extensors and hip flexors to transfer the mechanical energy more effectively to the support thigh and shank. 相似文献
18.
Toru Ishihara Toshihiro Nakajima Koichi Okita Koji Yamatsu Masato Sagawa 《European Journal of Sport Science》2018,18(2):286-294
The purpose of this study was to determine, using structural equation modelling (SEM), the direct and indirect influence of daily behaviours (i.e. exercise/learning durations), weight status, and physical fitness on academic performance among seventh-grade schoolchildren, after controlling for socioeconomic status. We analysed cross-sectional data from 274 schoolchildren (159 males and 115 females; 12–13 years old). Academic performance was assessed using the total grade points in eight academic subjects. Physical fitness was evaluated using the total score of eight physical fitness tests and weight status using body mass index. The daily behaviours and socioeconomic status were assessed by the questionnaire. The SEM showed an adequate fit to the data (χ2?=?0.684, p?=?.710, RMSEA?=?.000). Physical fitness and learning durations had direct effects on academic performance (β?=?.301, p?β?=?.132, p?=?.037, respectively) after controlling for confounders. Healthy weight status and exercise habits positively indirectly influenced academic performance via physical fitness. These findings suggest that, independent of socioeconomic status and learning durations, exercise habits and maintaining healthy weight status may indirectly contribute to academic success via better physical fitness in children. 相似文献
19.
Kadota K Matsuo T Hashizume K Tezuka K 《Research quarterly for exercise and sport》2004,75(2):138-147
We examined changes in the usage of muscular and motion-dependent moments during the long-term practice of a complex, multijoint movement. Seven participants practiced a cyclic movement of the upper limbs until their joint angular movements conformed to those of an expert. The motions of the participants were digitally recorded using four high-speed infrared cameras, and the joint kinematics and kinetics of the right arm were calculated. Practice brought about changes in the patterns of the net joint moment and in the contributions of the muscular and motion-dependent moments to the net moments. Practice also brought about a growing opposition between the directions of the two moments. These changes seemed to be important for improving the dynamic equilibrium of the movements. 相似文献
20.