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Bioturbation Effects of Branchiura sowerbyi (Tubificidae) on the Vertical Transport of Sedimentary Particles in Paddy Field 被引量:2
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作者 孙刚 房岩 +1 位作者 王平 丛大力 《Agricultural Science & Technology》 CAS 2010年第8期117-119,共3页
[Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and ... [Objective] The research aimed to investigate the bioturbation effects of Branchiura sowerbyi (Tubificidae) on the vertical transport of sedimentary particles in paddy field,and explore the bioturbation effects and mechanism of benthic Annelida in coupling process of benthic-pelagic interface.[Method]Using chemically stable glass beads as tracers,the vertical transport of sedimentary particles in paddy field was analyzed comparatively with and without B.sowerbyi.[Result]After 10 days' bioturbation of B.sowerbyi,41.3% of the glass beads on the surface of sedimentary particles were transferred downward to the maximum depth of 9.4 cm,and the vertical transportation rate of sedimentary particles was 1.370×10-3/(g·cm2·d). 25.8% and 17.3% of glass beads at a depth of 6 cm were transferred upwards and downwards respectively after bioturbation,to the maximum depth of 5.2 and 2.7 cm respectively,and the vertical transportation rates of sedimentary particles were 8.557×10-4 and 5.738×10-4/(g·cm2·d) respectively.[Conclusion]The sedimentary particles on the surface and deep layer of the paddy field were vertically shifted by the physical activities of B.sowerbyi,thus changed the sedimentary environment. 展开更多
关键词 Branchiura sowerbyi Paddy field BIOTURBATION SEDIMENT Vertical transport
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Anguilliform Fish Propulsion of Highest Hydrodynamic Efficiency
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作者 William S. Vorus Brandon M. Taravella 《Journal of Marine Science and Application》 2011年第2期163-174,共12页
It is hypothesized that steady anguilliform swimming motion of aquatic animals is purely reactive such that no net vortex wake is left downstream. This is versus carangiform and tunniform swimming of fish, where vorte... It is hypothesized that steady anguilliform swimming motion of aquatic animals is purely reactive such that no net vortex wake is left downstream. This is versus carangiform and tunniform swimming of fish, where vortex streams are shed from tail, fins, and body. But there the animal movements are such to produce partial vortex cancellation downstream in maximizing propulsive efficiency. In anguilliform swimming characteristic of the eel family, it is argued that the swimming motions are configured by the animal such that vortex shedding does not occur at all. However, the propulsive thrust in this case is higher order in the motion amplitude, so that relatively large coils are needed to produce relatively small thrust; the speeds of anguilliform swimmers are less than the carangiform and tunniforrn, which develop first order thrusts via lifting processes. Results of experimentation on live lamprey are compared to theoretical prediction which assumes the no-wake hypothesis. Two-dimensional analysis is first performed to set the concept. This is followed by three-dimensional analysis using slender-body theory. Slender-body theory has been applied by others in studying anguilliform swimming, as it is ideally suited to the geometry of the lamprey and other eel-like animals. The agreement between this new approach based on the hypothesis of wakeless swimming and the experiments is remarkably good in spite of the physical complexities. 展开更多
关键词 HYDRODYNAMICS fish propulsion propulsion efficiency
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Integrating biomechanical and motor control principles in elite high jumpers: A transdisciplinary approach to enhancing sport performance
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作者 James Becker Will EW. Wu 《Journal of Sport and Health Science》 SCIE 2015年第4期341-346,共6页
Background: In recent years, there has been a proliferation of technology and sport science utilized within an athlete's training, especially at the elite level. However, the sport science is a broad field, encompas... Background: In recent years, there has been a proliferation of technology and sport science utilized within an athlete's training, especially at the elite level. However, the sport science is a broad field, encompassing disciplines such as biomechanics, motor control and learning, exercise physiology, sports medicine, sport psychology to name a few. Rarely are these disciplines applied in an integrated manner. The purpose of this study was to document the effectiveness of an integrated biomechanics and motor control protocol for improving athlete's performance in the high jump. Methods: Four elite high jumpers performed baseline jumps under no^mal conditions and then jumps using a specific external focus of attention cue designed to improve their running posture. Three-dimensional biomeehanical analysis was used to quantify the upright posture throughout the approach as well as horizontal velocity at plant and vertical velocity at takeoff. Results: The results showed that when using the external focus of attention cue, the jumpers were significantly more upright during the approach, had significantly higher horizontal velocities at plant, and generated significantly greater vertical velocities during the takeoff. Conclusion: The results of this study lay the foundation for future work examining how integrating sport science disciplines can improve performance of elite level athletes. 展开更多
关键词 BIOMECHANICS High jump Motor control Sport performance
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东方田鼠的游泳行为和能力 被引量:2
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作者 张琛 王勇 张美文 《动物学杂志》 CAS CSCD 北大核心 2019年第3期311-320,共10页
东方田鼠(Microtus fortis)是一种栖息于湿地生境的小型哺乳动物,为了解其水生运动适应,作者在实验室内观察和测试了该鼠的游泳行为、皮毛防水性能和长时间游泳能力。结果发现,东方田鼠主要在水面游泳,亦能潜水,游泳姿势是狗刨式,并主... 东方田鼠(Microtus fortis)是一种栖息于湿地生境的小型哺乳动物,为了解其水生运动适应,作者在实验室内观察和测试了该鼠的游泳行为、皮毛防水性能和长时间游泳能力。结果发现,东方田鼠主要在水面游泳,亦能潜水,游泳姿势是狗刨式,并主要以后肢交替划水提供推进力,速度约为0.37 m/s。在20℃水温条件下,东方田鼠皮毛表现出良好的防水性能,且防水性能与其年龄及体重均存在极显著的负相关关系(P <0.01,R^2=0.805);东方田鼠具有平均约持续5 h以上的长时间游泳能力,且长时间游泳能力与其皮毛防水性能存在极显著的正相关关系(P <0.01,R^2=0.682);上述两项指标性别差异显著。这表明,东方田鼠有较强的水中运动能力和长时间游泳能力,具有水生运动方面的适应性进化,有利于其在沼泽等栖息地的生存。 展开更多
关键词 东方田鼠 水生运动 皮毛防水性 游泳行为 长时间游泳能力
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