Heart rate variability during high-intensity exercise

The aim of this paper is to describe and analyse the behaviour of heart rate variability (HRV) during constant-load, high-intensity exercise using a time frequency analysis (Wavelet Transform). Eleven elite cyclists took part in the study (age: 18.6±3.0 years; VO_2max: 4.88±0.61 litres·min^?1). Initially, all subjects performed an incremental cycloergometer test to determine load power in a constant load-test (379.55±36.02 W; 89.0%). HRV declined dramatically from the start of testing (p <0.05). The behaviour of power spectral density within the LF band mirrored that of total energy, recording a significant decrease from the outset LF peaks fell rapidly thereafter, remaining stable until the end of the test. HF-VHF fell sharply in the first 20 to 30 seconds. The relative weighting (%) of HF-VHF was inverted with the onset of fatigue, [1.6% at the start, 7.1 (p <0.05) at the end of the first phase, and 43.1% (p <0.05) at the end of the test]. HF-VHF_peak displayed three phases: a moderate initial increase, followed by a slight fall, thereafter increasing to the end of the test. The LF/HF-VHF ratio increased at the start, later falling progressively until the end of the first phase and remaining around minimal values until the end of the test.     

集装箱船体波浪载荷应力短期分布的统计分析

基于对波浪载荷所引起的交变应力范围数据统计分析的结论，建议用一类双峰正态混合分布拟合．利用EM算法对混合分布的参数进行估计,借助估计出的参数值，揭示了在一定条件下船体不同部位疲劳载荷的固有关系．船体波浪载荷应力在船首处尤为复杂，双峰对称正态逆高斯混合分布对该处波浪载荷所引起的交变应力范围数据拟合效果更好．实证分析表明，所提供的概率分布参数能够反映船体不同部位的疲劳载荷大小，所得到的关于船体不同部位疲劳载荷固有关系的结论可为船舶运行品质研究提供理论基础．     

电势降落对DNA分子器件电荷输运的影响

基于晶格格林函数和Landauer-Büttiker公式,研究了脱氧核糖核酸分子器件在不同电势降落下的电荷输运性质。界面处的电势降落可以导致负微分电导现象的出现,而且随着电势降落在脱氧核糖核酸分子上的比例的提高,这个效应更加明显。电势降落导致的分子轨道的局域化是产生负微分电导现象的关键因素。     

The novel Cer-like protein Caronte mediates the establishment of embryonic left-right asymmetry.

In the chick embryo, left-right asymmetric patterns of gene expression in the lateral plate mesoderm are initiated by signals located in and around Hensen's node. Here we show that Caronte (Car), a secreted protein encoded by a member of the Cerberus/Dan gene family, mediates the Sonic hedgehog (Shh)-dependent induction of left-specific genes in the lateral plate mesoderm. Car is induced by Shh and repressed by fibroblast growth factor-8 (FGF-8). Car activates the expression of Nodal by antagonizing a repressive activity of bone morphogenic proteins (BMPs). Our results define a complex network of antagonistic molecular interactions between Activin, FGF-8, Lefty-1, Nodal, BMPs and Car that cooperate to control left-right asymmetry in the chick embryo.     

经济可持续发展与平顶山市科技发展战略

本文论述了经济可持续发展与科技发展的关系，认为平顶山市科技发展战略的模式包括优势技术战略和适用技术战略两个部分。     

对大学生学习武术动机的研究

本文主要分析了大学生在武术课教学过程中学习动机的类型和学习动机对学习成绩及身体素质的影响．研究表明，具有问接远景性学习动机的学生比具有直接近景性学习动机的学生的学习成绩和身体素质有明显的提高．所以，学习动机对学生学习成绩和身体素质的提高起着重要的作用．     

氟离子选择电极法测啤酒中的氟

本文采用氟离子电极法测定啤酒中的氟 ,测量溶液的酸度为PH5— 6,用总离子强度调节缓冲液 ,消除干扰离子及酸度的影响 ,方法回收率 96.1 2 %～ 99.2 4 % ,线性范围为 1 0 - 1 mol/L～ 5× 1 0 - 7mol/L ,最低检出浓度 0 .0 1 μg/ml,本法操作简单、快速 ,适合作常规测定 .     

《河南植物志》虎耳草科补遗

报道了《河南植物志》中未记录的虎耳草科植物9种5变种(均采有标本)。