A quantitative evaluation of the high elbow technique in front crawl     

Hiroshi Suito  Hiroyuki Nunome  Yasuo Ikegami 《Journal of sports sciences》2017,35(13):1264-1269

Many coaches often instruct swimmers to keep the elbow in a high position (high elbow position) during early phase of the underwater stroke motion (pull phase) in front crawl, however, the high elbow position has never been quantitatively evaluated. The aims of this study were (1) to quantitatively evaluate the “high elbow” position, (2) to clarify the relationship between the high elbow position and required upper limb configuration and (3) to examine the efficacy of high elbow position on the resultant swimming velocity. Sixteen highly skilled and 6 novice male swimmers performed 25 m front crawl with maximal effort and their 3-dimensional arm stroke motion was captured at 60 Hz. An attempt was made to develop a new index to evaluate the high elbow position (I_he: high elbow index) using 3-dimensional coordinates of the shoulder, elbow and wrist joints. I_he of skilled swimmers moderately correlated with the average shoulder internal rotation angle (r = ?0.652, P < 0.01) and swimming velocity (r = ?0.683, P < 0.01) during the pull phase. These results indicate that I_he is a useful index for evaluating high elbow arm stroke technique during the pull phase in front crawl.  相似文献   

Induction of alternative fate other than default neuronal fate of embryonic stem cells in a membrane-based two-chambered microbioreactor by cell-secreted BMP4     

Mahfuz Chowdhury M  Kimura H  Fujii T  Sakai Y 《Biomicrofluidics》2012,6(1):14117-1411713

Cell-secreted soluble factor signaling in a diffusion dominant microenvironment plays an important role on early stage differentiation of pluripotent stem cells invivo. In this study, we utilized a membrane-based two-chambered microbioreactor (MB) to differentiate mouse embryonic stem cells (mESCs) in a diffusion dominant microenvironment of the top chamber while providing enough nutrient through the bottom chamber. Speculating that accumulated FGF4 in the small top chamber will augment neuronal differentiation in the MB culture, we first differentiated mESCs for 8 days by using a chemically optimized culture medium for neuronal induction. However, comparison of cellular morphology and expression of neuronal markers in the MB with that in the 6-well plate (6WP) indicated relatively lower neuronal differentiation in the MB culture. Therefore, to investigate whether microenvironment in the MB facilitates non-neuronal differentiation, we differentiated mESCs for 8 days by using chemically defined basal medium. In this case, differentiated cell morphology differed markedly between the MB and 6WP cultures: epithelial sheet-like morphology in the MB, whereas rosette morphology in the 6WP. Expression of markers from the three germ layers indicated lower neuronal but higher meso- and endo-dermal differentiation of mESCs in the MB than the 6WP culture. Moreover, among various cell-secreted soluble factors, BMP4 expression was remarkably upregulated in the MB culture. Inhibition of BMP4 signaling demonstrated that enhanced effect of upregulated BMP4 was responsible for the prominent meso- and endo-dermal differentiation in the MB. However, in the 6WP, downregulated BMP4 had a minimal influence on the differentiation behavior. Our study demonstrated utilization of a microbioreactor to modulate the effect of cell-secreted soluble factors by autoregulation and thereby inducing alternative self-capability of mESCs. Understanding and implementation of autoregulation of soluble factors similar to this study will lead to the development of robust culture systems to control ESC behavior.  相似文献   

The Role of Educational Research in Educational Improvements     

Hiroshi Kida 《Asia Pacific Journal of Education》1984,6(2):54-59

Educational research is an undertaking to review and improve educational practice. In one case, educational practitioners conduct research by themselves in order to review their own practices, while in another, non-practitioners undertake the research. Educational practice here will refer to the individual instructional activities of school teachers on the one hand and the organized activities or programmes of educational institutions or educational systems on the other.  相似文献   

Effects of forced movements on learning: Findings from a choice reaction time task in rats     

Hidekazu Kaneko  Hiroto Sano  Yasuhisa Hasegawa  Hiroshi Tamura  Shinya S. Suzuki 《Learning & behavior》2017,45(2):191-204

To investigate how motor sensation facilitates learning, we used a sensory–motor association task to determine whether the sensation induced by forced movements contributes to performance improvements in rats. The rats were trained to respond to a tactile stimulus (an air puff) by releasing a lever pressed by the stimulated (compatible condition) or nonstimulated (incompatible condition) forepaw. When error rates fell below 15%, the compatibility condition was changed (reversal learning). An error trial was followed by a lever activation trial in which a lever on the correct or the incorrect response side was automatically elevated at a preset time of 120, 220, 320, or 420 ms after tactile stimulation. This lever activation induced forepaw movement similar to that in a voluntary lever release response, and also induced body movement that occasionally caused elevation of the other forepaw. The effects of lever activation may have produced a sensation similar to that of voluntary lever release by the forepaw on the nonactivated lever. We found that the performance improvement rate was increased by the lever activation procedure on the incorrect response side (i.e., with the nonactivated lever on the correct response side). Furthermore, the performance improvement rate changed depending on the timing of lever activation: Facilitative effects were largest with lever activation on the incorrect response side at 320 ms after tactile stimulation, whereas hindering effects were largest for lever activation on the correct response side at 220 ms after tactile stimulation. These findings suggest that forced movements, which provide tactile and proprioceptive stimulation, affect sensory–motor associative learning in a time-dependent manner.  相似文献   

Recognition of static and dynamic images of depth-rotated human faces by pigeons     

Jitsumori M  Makino H 《Learning & behavior》2004,32(2):145-156

In three experiments, we examined pigeons’ recognition of video images of human faces. In Experiment 1, pigeons were trained to discriminate between frontal views of human faces in a go/no-go discrimination procedure. They then showed substantial generalization to novel views, even though human faces change radically as viewpoint changes. In Experiment 2, the pigeons tested in Experiment 1 failed to transfer to the faces dynamically rotating in depth. In Experiment 3, the pigeons trained to discriminate the dynamic stimuli showed excellent transfer to the corresponding static views, but responses to the positive faces decreased at novel viewpoints outside the range spanned by the dynamic stimuli. These results suggest that pigeons are insensitive to the three-dimensional properties of video images. Consideration is given to the nature of the task, relating to the identification of three-dimensional objects and to perceptual classifications based on similarity judgments.  相似文献   

Discriminated and nondiscriminated avoidance conditioning of the rearing response in rats     

Akira Shishimi  Hiroshi Imada 《Learning & behavior》1977,5(3):259-264

Experiment 1 employed a shock box in which light beams ran at 10, 15, 20, or 25 cm above the floor level of the box. Four groups of nine rats each were trained to avoid shock by cutting the light beams or letting them pass by, which the animal accomplished by upward or downward change of its posture. Training employed a discriminated avoidance paradigm, 60 trials per day for 5 days, with a 5-sec CS-US interval. Acquisition of the rearing avoidance response was observed only in the 15-cm condition. Using the same apparatus as in Experiment 1 and with a beam height of 15 cm, the rearing avoidance response was successfully conditioned in five rats using a nondiscriminated avoidance conditioning paradigm. There was good evidence of temporal discrimination in these animals.  相似文献   

从《七发》到《天子游猎赋》——脱离上古文学传统，确立汉赋表现世界     

谷口洋 《四川师范大学学报(社会科学版)》2005,32(5):80-88

枚乘《七发》开创了汉大赋这一体式，是司马相如《天子游猎赋》的直接祖先。但枚乘的《七发》背后还存在着古老的师承，司马相如的作品却脱离了上古文学传统，确立了汉赋的表现世界，标志着汉赋新的发展方向。  相似文献   

CHEⅢ型脉冲电泳仪获得清晰电泳效果的实验探索     

尹良芬  罗朝喜  八重樫博志 《实验技术与管理》2011,28(1)

CHEF Ⅲ型脉冲电泳仪是微生物种类鉴定、DNA大分子分离等基础科学研究中一个不可或缺的重要工具。该仪器可以快速、高效、准确地分离200 kb到6 Mb的DNA分子。因此,在染色体数目及染色体大小的确定、核型分析、遗传图谱分析、同源性检测分析等方面有关键性的作用。然而在实验过程中要使DNA分子完全、有效地分离,得到清晰、高效的条带却并非易事。本实验基于这些问题,经过一系列的探索研究,找到了稻瘟病菌及分子量标准酵母菌染色体分离所需要的最适条件,该条件能为分离其他真菌染色体提供借鉴与参考。  相似文献   

稻瘟病菌原生质体制备条件优化实验研究   总被引：1，自引：0，他引：1  

尹良芬  八重樫博志 《实验技术与管理》2011,28(4):33-35

原生质体的制备一直是现代分子生物学研究的重要内容。以稻瘟病菌作为供试菌株,优化了其原生质体的制备条件。优化的原生质体制备条件包括:使用新鲜的菌丝进行接种;加入玻璃珠一起培养,通过振荡使菌丝体破碎分离以获得更多的生长点;菌悬液继续加入新鲜培养液进行培养;原生质体沉淀时选择3 000r/min离心10min,保证最大限度地收集原生质体。实验证明,通过这4个条件优化后,原生质体的产量有了极大的提高,每毫升酶液可制备10 8～109个原生质体。  相似文献   

城市发展与环境:高等教育的任务     

小宫山宏  吕春辉 《复旦教育论坛》2005,3(6):18-19

早上好。我是东京大学校长小宫山宏。很荣幸参加复旦大学的百年庆典。在这样的场合,提出城市和高等教育相互关系这样的话题再合适不过了。虽然城市的可持续性发展的话题已经成为世界范围内的兴趣热点,但高等教育在社会中的作用还是受到诸多质疑。在此专题讨论会中,我想就高等教育如何促进城市和环境的发展进行论述。  相似文献