核酸四碱基体及四螺旋模型的理论构建

核酸的结构具有多态性 ,核酸的功能取决于其结构 .了解核酸不同结构的特征有利于对其功能的充分认识 .本文对核酸四碱基体及其形成的四链结构模型进行了理论研究 .这些工作有助于从理论上进一步研究核酸四螺旋结构 ,对相关的实验研究也将起到有益参考作用 .     

企业战略成本管理与核心竞争力培育

企业要在激烈的市场竞争中立于不败之地,必须进行成本管理改革。把成本管理贯穿于生产经营的整个过程。因此,我国企业应导入战略成本管理,以此作为提升核心竞争力的利器。     

部分优秀网球运动员反手切削球技战术研究

采用文献法、观察与分析法、访谈法等多种研究方法,对网球反手切削球技术、战术进行比较全面系统的探讨,总结分析国内、外优秀网球运动员运用反手切削技术、战术的特点及规律,为进一步提高我国网球运动水平提供参考依据。     

Optimized versus corrected peak power during friction-braked cycle ergometry in males and females

The aim of this study was to compare optimization and correction procedures for the determination of peak power output during friction-loaded cycle ergometry. Ten male and 10 female sports students each performed five 10-s sprints from a stationary start on a Monark 864 basket-loaded ergometer. Resistive loads of 5.0, 6.5, 8.0, 9.5, and 11.0% body weight were administered in a counterbalanced order, with a recovery period of 10 min between sprints. Peak power was greater and occurred earlier, with less work having been done before the attainment of peak power, when the data were corrected to account for the inertial and frictional characteristics of the ergometer. Corrected peak power was independent of resistive load (P > 0.05), whereas uncorrected peak power varied as a quadratic function of load (P < 0.001). For males and females, optimized peak power (971 +/- 122 and 668 +/- 37 W) was lower (P < 0.01) than either the highest (1074 +/- 111 and 754 +/- 56 W respectively) or the mean (1007 +/- 125 and 701 +/- 45 W respectively) of the five values for corrected peak power. Optimized and mean corrected peak power were highly correlated both in males (r = 0.97, P < 0.001) and females (r = 0.96, P < 0.001). The difference between optimized and mean corrected peak power was 37 +/- 30 W in males and 33 +/- 14 W in females, of which approximately 15 W was due to the correction for frictional losses. We conclude that corrected peak power is independent of resistive load in males and females.     

Relationship between maximal oxygen uptake and oxygen uptake attained during treadmill middle-distance running

Traditionally, it has been assumed that during middle-distance running oxygen uptake (VO2) reaches its maximal value (VO2max) providing the event is of a sufficient duration; however, this assumption is largely based on observations in individuals with a relatively low VO2max. The aim of this study was to determine whether VO2max is related to the VO2 attained (i.e. VO2peak) during middle-distance running on a treadmill. Fifteen well-trained male runners (age 23.3 +/- 3.8 years, height 1.80 +/- 0.10 m, body mass 76.9 +/- 10.6 kg) volunteered to participate in the study. The participants undertook two 800-m trials to examine the reproducibility of the VO2 response. These two trials, together with a progressive test to determine VO2max, were completed in a randomized order. Oxygen uptake was determined throughout each test using 15-s Douglas bag collections. Following the application of a 30-s rolling average, the highest VO2 during the progressive test (i.e. VO2max) was compared with the highest VO2 during the 800-m trials (i.e. VO2peak) to examine the relationship between VO2max and the VO2 attained in the 800-m trials. For the 15 runners, VO2max was 58.9 +/- 7.1 ml x kg(-1) x min(-1). Two groups were formed using a median split based on VO2max. For the high and low VO2max groups, VO2max was 65.7 +/- 3.0 and 52.4 +/- 1.8 ml x kg(-1) x min(-1) respectively. The limits of agreement (95%) for test-retest reproducibility for the VO2 attained during the 800-m trials were +/- 3.5 ml x kg(-1) x min(-1) for a VO2peak of 50.6 ml x kg(-1) x min(-1) (the mean VO2peak for the low VO2max group) and +/- 2.3 ml x kg(-1) x min(-1) for a VO2peak of 59.0 ml x kg(-1) x min(-1) (the mean VO2peak for the high VO2max group), with a bias in VO2peak between the 800-m runs (i.e. the mean difference) of 1.2 ml x kg(-1) x min(-1). The VO2peak for the 800-m runs was 54.8 +/- 4.9 ml x kg(-1) x min(-1) for all 15 runners. For the high and low VO2max groups, VO2peak was 59.0 +/- 3.3 ml x kg(-1) x min(-1) (i.e. 90% VO2max) and 50.6 +/- 2.0 ml x kg(-1) x min(-1) (i.e. 97% VO2max) respectively. The negative relationship (-0.77) between VO2max and % VO2max attained for all 15 runners was significant (P = 0.001). These results demonstrate that (i) reproducibility is good and (ii) that VO2max is related to the %VO2max achieved, with participants with a higher VO2max achieving a lower %VO2max in an 800-m trial on a treadmill.     

从"十运会"中存在的问题引发的对"举国体制"的理性思考

南京十运会赛场上上演了一幕幕丑闻,对全运会还要不要继续办下去,人们对此产生了质疑,并引发对举国体制的思考。根据我国的国情和经济发展水平等各个方面因素来阐述了对举国体制的看法,对我国体育事业发展的趋势提出了建议。     

我国高水平健美操运动员踝关节损伤的致因分析

对造成我国高水平健美操运动员踝关节损伤的原因进行调查与分析,目的是为了保证健美操运动训练能顺利的进行,在比赛中取得优异成绩,同时也为健美操训练与比赛在防止踝关节损伤的发生提供参考依据。     

陕西省高校体育场馆对外开放立法保障现状分析

高校体育场馆对外开放立法对促进陕西省全民健身活动具有重要的保障意义。现行立法规定为配套立法明确了主要方向和基本原则,但也存在立法体系不健全、立法内容相对单薄、缺乏强制保障性和实践操作性不强等方面的立法不足。造成目前立法不足的主要障碍包括政府立法重视不够、职能部门推诿责任以及高校自身困难限制等因素。     

健身干预对辽宁地区青少年不同年龄组体质影响的研究

依据不同年龄组青少年生长发育规律,分别有针对性地设计了健身干预方案,在大课间体育活动中具体实施,每天有组织地进行30～50min的锻炼,每周3次,平均心率为110～140次/min。共实验10周。结果表明:针对不同年龄学生设计的健身方案对这些被测学生的身体形态、生理机能以及运动素质均产生了一定的影响。其中,初高中组学生的身体机能指标均有相对明显的变化,各组学生的握力体重指数和平衡能力等部分身体素质指标变化也较为明显,但各组学生的身体形态指标基本没有明显变化。