Critical cyclic stress ratio of undisturbed saturated soft clay in the yangtze estuary under complex stress conditions

There exists a critical cyclic stress ratio when sand or clay is subjected to cyclic loading. It is an index distinguishing stable state or failure state. The soil static and dynamic universal triaxial and torsional shear apparatus developed by Dalian University of Technology in China was employed to perform different types of tests on saturated soft marine clay in the Yangtze estuary. Undisturbed samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear after three-directional anisotropic consolidation with different initial consolidation parameters. The effects of initial orientation angle of major principal stress, initial ratio of deviatoric stress, initial coefficient of intermediate principal stress and stress mode of cyclic shear on the critical cyclic stress ratio were investigated. It is found that the critical cyclic stress ratio decreases significantly with increasing initial orientation angle of major principal stress and initial ratio of deviatoric stress. Compared with the effects of the initial orientation angle of major principal stress and initial ratio of deviatoric stress, the effect of initial coefficient of intermediate principal stress is less evident. Under the same consolidation condition, the critical cyclic stress ratio from the cyclic coupling shear test is lower than that from the cyclic torsional shear test, indicating that the stress mode of cyclic shear has an obvious effect on the critical cyclic stress ratio. The main reason is that the continuous rotation in principal stress directions during cyclic coupling shear damages the original structure of soil more than the cyclic torsional shear does.     

优秀女子摔跤运动员赛前压力情绪、应激应对水平与运动成绩的关系的研究

本文通过运用问卷调查与心理学实验的研究方法,分析不同级别女子摔跤运动员赛前情绪、应激应对方式、自主平衡调节能力的差异。结果表明:运动等级较高的运动员的个人失败焦虑和社会期待焦虑会明显低于其他水平运动员。健将级的女子摔跤训动员面对比赛时,应激应对方式,自我平衡能力均优于国家一级的女子摔跤运动员。     

Influence of aerobic versus anaerobic exercise on the relationship between reproductive hormones in men

This study examined the effects of equal anaerobic and aerobic total work outputs on the relationship between reproductive hormones in men. Nine subjects performed three randomized trials on separate days: (1) 1 h period of rest (control), (2) 1 h continuous aerobic exercise (65% VO₂ max), and (3) 1 h intermittent anaerobic exercise (which included 2 min exercise periods at 110% FO₂ max). The total work output of the aerobic and anaerobic trials were equated. For the 8 h after each experimental trial, blood samples were collected hourly and analysed for testosterone, luteinizing hormone (LH), follicle‐stimulating hormone (FSH), prolactin and cortisol. Diet, physical activity and circadian influences were all controlled. Compared with the control, the aerobic and anaerobic trials significantly (P < 0.05) elevated testosterone, prolactin and cortisol; however, these changes were transient and returned to control levels within 1–2 h of recovery. Neither exercise produced significant (P > 0.05) changes from control for LH and FSH. The area under the hormonal response curves (AUC) was calculated for the 8‐h recovery period. The testosterone and LH AUC results did not differ (P > 0.05) among the trials (the FSH AUC was not calculated). The prolactin AUC for the aerobic and anaerobic trials were greater (P < 0.01) than the control trial. The cortisol AUC for the anaerobic trial was greater than both the control and aerobic trials (P < 0.05), but the aerobic and control trials did not differ from one another. Correlation analysis among the AUC results within each trial showed testosterone and LH to be significantly related during the control (r = 0.723, P < 0.05) and aerobic (r = 0.801, P < 0.01) trials, but not so during the anaerobic trial (r = 0.430, P > 0.05). No other significant correlations were found. The present findings suggest the relationship between testosterone and LH is affected by anaerobic exercise but not aerobic exercise. However, the effect of anaerobic exercise upon the testosterone‐LH relationship did not seem related to the concurrently induced prolactin or cortisol changes. Anaerobic exercise may produce some degree of temporary alteration within the testosterone‐LH component of the hypothalamic‐pituitary‐gonadal axis; however, the mechanism for this phenomenon remains unclear.     

优秀射箭运动员竞赛压力认知评估影响因素

采用情景脚本的方法探索运动员认知评估的可能影响因素。依据压力—应对认知交互理论,总结以往的研究成果,提出3种可能的影响因素:压力事件类型、教练员的态度和运动员的心理控制源,并进一步探讨这3种因素如何影响运动员竞技压力认知评估。结果表明:(1)心理控制源不同的优秀射箭运动员竞技压力认知评估存在差异;(2)不同压力事件类型对优秀射箭运动员认知评估的影响差异不显著;(3)不同的教练员态度对优秀射箭运动员的竞赛压力认知评估影响差异并不显著,只有在失败控制点上差异显著。     

工作压力的应对与管理

工作压力是由于个体感知能力与工作要求的不匹配,或者是个体感知到工作前景的不确定性而产生的心理及生理上的不适应。现代信息社会的到来,这种压力愈发凸显。因此,如何科学地对待,正确分析工作压力,不仅可以提高工作绩效,同时也是应对瞬息万变社会,提高自身生存能力的最佳选择。     

摔跤运动员比赛前后血液微量元素和抗氧化能力的变化

血液微量元素和抗氧化能力与运动员的体能以及生理状态密切相关。研究旨在通过对比摔跤运动员在比赛前后的抗氧化能力和微量元素水平的变化,从而为青少年运动员的营养补充提供理论依据。方法:选取24名我国优秀青少年(12名女性和12名男性)运动员为受试对象,通过模拟高强度的摔跤比赛,并在比赛前后采集运动员的血液样本,检测血液中活性氧(ROS)含量,抗氧化剂酶的活性以及硒、锌、铁、铜、镁和锰的浓度,测评受试者的血液微量元素与抗氧化能力。结果:运动员在摔跤比赛后,无论男、女运动员,血液中镁元素含量显著增加,硒元素含量显著下降。结果显示:硒元素的变化与氧化应激指标以及抗氧化酶的变化呈现密切的相关性。其中活性氧指标与赛前静态相比表现出显著的统计学差异,呈现明显的氧化应激状态。研究提示:对摔跤运动员进行硒元素的补充极为必要。     

运动对心理应激神经免疫影响研究的分析与展望

综述了国内运动与应激分别对激素、细胞因子、神经肽的影响的研究,以及运动与应激交互作用对激素、细胞因子、神经肽影响的研究现状、存在的问题和未来的发展方向。借此为我国运动与心理神经免疫系统研究者提供一些参考。     

中草药对热应激蛋鹌鹑生产性能及部分血液生化指标的影响

选取100日龄健康北京蛋鹌鹑6000只,随机分成3组,A组为对照组,B、C组分别给予中草药粉剂、冲剂,按日粮的0．1％添加。试验表明：40天的试验期内,试验组与对照组相比料蛋比、产蛋总重、产蛋率、蛋破损率、死淘率、经济效益差异显著（P〈0．05）,平均蛋重、畸形蛋差异不显著（P〉0．05）;血清总蛋白、血清白蛋白、血清球蛋白、血钙、血磷、碱性磷酸酶、总甲状腺激素（T3、T4）升高（P〈0．05）,血糖、乳酸脱氢酶、皮质醇（Cor）下降（P〈O．05）,雌二醇（E2）变化不显著（P〉0．05）。     

对青少年运动员应力性骨折的分析

应力性骨折是运动性损伤的常见病,由于青少年特殊的解剖生理学特点使其较易发生应力性骨折,文章从应力性骨折发生的生物力学基础,应力性骨折易发部位的生物力学原理,应力性骨折的影像学诊断,应力性骨折的预防与治疗等几方面进行分析,以使运动员及教练员能充分认识应力性骨折产生的原因,做到对应力性骨折的早发现、早诊断和早治疗,减少运动员的损伤,提高训练的质量,延长运动员的运动寿命。