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1.
Umeda T Nakaji S Shimoyama T Yamamoto Y Totsuka M Sugawara K 《Journal of sports sciences》2004,22(4):329-338
In this study, we examined the effects of weight reduction by restricting energy intake on muscle function and serum concentrations of myogenic enzymes in judoists. Twenty-seven male judoists aged 19.3 +/- 0.6 years (mean +/- s) were divided into three groups based on the extent of body weight reduction: high weight reduction (height 1.70 +/- 0.05 m, body mass 78.5 +/- 13.6 kg), low weight reduction (height 1.70 +/- 0.05 m, body mass 80.7 +/- 13.1 kg) and a group that maintained body weight while continuing to perform exercise training (height 1.78 +/- 0.07 m, body mass 78.7 +/- 8.8 kg). Body composition, blood biochemistry, energy intake and anaerobic power were assessed on four occasions: 20 days (baseline data), 4 days and 1 day before and 7 days after competition. Compared with baseline, body mass and fat-free mass were significantly lower 1 day before competition in the high and low weight reduction groups (both P < 0.01); these changes persisted for 7 days after competition in the high weight reduction group. Serum creatine kinase was significantly elevated 1 day before competition in all groups (all P < 0.05), and remained higher 7 days after competition in both the high and low weight reduction groups. Compared with baseline, maximal anaerobic power was significantly lower 1 day before competition only in the high weight reduction group (P < 0.01). Our results suggest that energy restriction in addition to intense exercise training before major competition has an adverse effect on anaerobic power and elevates serum creatine kinase concentration, leading to an impairment of muscular function and an increased susceptibility of muscle tissue to injury. 相似文献
2.
Three experiments were performed to address factors contributing to the Ponzo illusion. In Experiment 1, pigeons learned to peck at the longer of two bars in varying line contexts. When these lines converged, the birds had difficulty in learning several patterns in which a Ponzo illusion would reduce the perceived difference. In Experiment 2, the subjects chose one response if a stimulus bar was longer than a predetermined length and a second response for shorter bars. The subjects were more likely to choose “long” as the stimulus bar approached the apex of converging lines. These results suggested that pigeons experience the Ponzo illusion. In Experiment 3, the effects of contexts that did and did not form a texture gradient were compared. The magnitude of the illusion did not differ according to context lines. This result failed to support a perspective theory of the Ponzo illusion. 相似文献
3.
Complexation of π-conjugated ligands by metal or semimetal ions leads to the enhancement of the planarity and rigidity of π-conjugated systems. Boron, especially, has played a central role in the design of luminescent main-group complexes. However, these complexes still suffer the disadvantage of aggregation-caused quenching as well as typical organic fluorophores. It has recently been reported that some types of boron complexes exhibit the aggregation-induced emission (AIE) property. Moreover, AIE behavior from complexes and organometallic compounds composed of the other group 13 elements, such as aluminum and gallium, has emerged in this decade. These observations greatly encourage us to develop advanced functional materials based on the group 13 elements. Indeed, recent research has demonstrated that these classes of materials are potentially versatile scaffolds for constructing chromic luminophores, efficiently emissive π-conjugated polymers and so on. This review mainly describes AIE-active group 13 complexes with four-coordinate structures and their application as photo-functional materials. Proposed mechanisms of the origins of AIE behavior are briefly discussed. 相似文献
4.
This study investigated the variations of perspectives of junior high school students who had participated in Smartphone Summit for appropriate usage of the Internet and smartphones. Smartphone Summit is an educational project designed to empower junior high school students to advocate appropriate usage of the Internet and smartphones among older, same-age, and younger peers, within school communities and society as a whole. The participants were 26 students (7th and 8th grade) from 18 junior high schools in Okayama, a western Japanese city. In the project, the participants discussed pros and cons of the Internet and smartphones, and presented their ideas concerning possible activities to encourage their classmates to use the Internet and smartphones in appropriate ways with the help of various adult experts. A questionnaire was administered to measure the participants’ evaluation of their own and their classmates’ present smartphone usage as well as anticipated future smartphone usage. Results showed that the participants evaluated their own usage as more appropriate than that of their classmates and expected that future usage would be better for both themselves and their classmates than at present. Furthermore, the participants expected their classmates’ usage will change more significantly than their own because their classmates’ current usage seems relatively inappropriate and there would be larger room for improvement. From the analysis of patterns of participants’ impact expectation toward their peers, it was found that there were three types of perspectives: moderate, relatively lower, and relatively higher evaluation. Future research should focus on the factors influencing the participants’ perspectives. 相似文献
5.
Hideki Takagi Motomu Nakashima Yohei Sato Kazuo Matsuuchi 《Journal of sports sciences》2016,34(16):1564-1580
This paper reviews unsteady flow conditions in human swimming and identifies the limitations and future potential of the current methods of analysing unsteady flow. The capability of computational fluid dynamics (CFD) has been extended from approaches assuming steady-state conditions to consideration of unsteady/transient conditions associated with the body motion of a swimmer. However, to predict hydrodynamic forces and the swimmer’s potential speeds accurately, more robust and efficient numerical methods are necessary, coupled with validation procedures, requiring detailed experimental data reflecting local flow. Experimental data obtained by particle image velocimetry (PIV) in this area are limited, because at present observations are restricted to a two-dimensional 1.0 m2 area, though this could be improved if the output range of the associated laser sheet increased. Simulations of human swimming are expected to improve competitive swimming, and our review has identified two important advances relating to understanding the flow conditions affecting performance in front crawl swimming: one is a mechanism for generating unsteady fluid forces, and the other is a theory relating to increased speed and efficiency. 相似文献
6.
This study investigated whether 2-, 3-, and 4-year-olds use their video feedback as a reflection of their current state, even when their feedback was presented with a short temporal delay. In Experiment 1, the effects of 1- and 2-s delayed feedback were examined on an analog of the mark test. In the case of live and 1-s delayed feedback, 3-year-olds passed the test; however, they failed in the case of 2-s delayed feedback. Experiment 2 examined the effect of prior experience of delayed contingency and explorative behavior. The results showed a significant effect of prior experience. These results suggest that detection of visual-proprioceptive contingency contributes to recognition of visual feedback as one's current self. 相似文献
7.
Akitoshi Uchida Kazuo Mori 《International Journal of Science and Mathematics Education》2018,16(6):1115-1126
International surveys repeatedly showed that Japanese children were good at mathematics but disliking it. We hypothesized there were a considerable number of “fake math-dislikes” among Japanese students who claimed they disliked mathematics explicitly but accepted it implicitly. To examine this hypothesis, we administered questionnaires and paper-based implicit association tests (IAT) to 204 Japanese junior high school students (13–14 years old) and found 38 fake math-dislikes (Study 1). We hypothesized further that those fake math-dislikes would become real math-dislikes eventually and that informing of their implicit attitude toward mathematics might work preventing this undesirable transition. Then, in Study 2, we randomly assigned them into experimental and control groups and informed only the experimental students of their positive implicit attitude toward mathematics we revealed with the IAT. One year later, we found 15 of the 16 experimental students improved their math achievement scores while only 9 of the 17 control students did. The simple practice of informing of their implicit attitude worked effectively for improving their math achievement. As hypothesized, it prevented the fake math-dislike students from turning into real math-dislikes. 相似文献
8.
We trained two budgerigars (Melopsittacus undulatus) with operant techniques in a delayed matching-to-sample task using pairs of acoustic stimuli. These stimuli included simple pure tones, complex, species-specific vocalizations, and tone-vocalization combinations. The birds were then tested with different retention intervals. The budgerigars’ short-term memory was similar for complex, species-specific vocalizations and for simple pure tones. By contrast, they showed significantly better short-term memory when tested with two sounds drawn from different acoustic categories. 相似文献
9.
Kazuo Yano 《Mind, Brain, and Education》2013,7(1):19-29
There is a missing link between our understanding of teaching as high‐level social phenomenon and teaching as a physiological phenomenon of brain activity. We suggest that the science of human interaction is the missing link. Using over one‐million days of human‐behavior data, we have discovered that collective activeness (CA), which indicates the simple high‐frequency‐motion ratio of a group to total time, plays a fundamental role. Even solo‐work performance, such as telephone‐sales success rate, is more influenced by CA than by one's individual skill level, which has been the conventional target of employee efficiency education. CA is experimentally found to drive people collectively to challenge for greater performance and happiness through a synchronized proactive mind. This is, in fact, deeply related to understanding the question “What is teaching?” 相似文献
10.
Takashi Umeda Shigeyuki Nakaji Tadashi Shimoyama Youske Yamamoto Manabu Totsuka Kazuo Sugawara 《Journal of sports sciences》2013,31(4):329-338
In this study, we examined the effects of weight reduction by restricting energy intake on muscle function and serum concentrations of myogenic enzymes in judoists. Twenty-seven male judoists aged 19.3±0.6 years (mean±s) were divided into three groups based on the extent of body weight reduction: high weight reduction (height 1.70±0.05?m, body mass 78.5 ±13.6?kg), low weight reduction (height 1.70±0.05?m, body mass 80.7±13.1?kg) and a group that maintained body weight while continuing to perform exercise training (height 1.78± 0.07?m, body mass 78.7±8.8?kg). Body composition, blood biochemistry, energy intake and anaerobic power were assessed on four occasions: 20 days (baseline data), 4 days and 1 day before and 7 days after competition. Compared with baseline, body mass and fat-free mass were significantly lower 1 day before competition in the high and low weight reduction groups (both P?<0.01); these changes persisted for 7 days after competition in the high weight reduction group. Serum creatine kinase was significantly elevated 1 day before competition in all groups (all P?<0.05), and remained higher 7 days after competition in both the high and low weight reduction groups. Compared with baseline, maximal anaerobic power was significantly lower 1 day before competition only in the high weight reduction group (P?<0.01). Our results suggest that energy restriction in addition to intense exercise training before major competition has an adverse effect on anaerobic power and elevates serum creatine kinase concentration, leading to an impairment of muscular function and an increased susceptibility of muscle tissue to injury. 相似文献