基于覆盖的模糊粗糙集模型

在基于覆盖的粗糙集的基础上,定义了基于覆盖的模糊粗糙集模型,并且讨论了该模型的一些相关性质.同时,证明了论域上的任意子集相对于覆盖近似空间及其约简后的覆盖近似空间的上下近似是分别相等的,从而简化了运算.     

一类一致混合超图的上、下色数

本文研究了在l、m固定的情况下,删除完全一致混合超图κ（n,l,m）的若干C-超边和D-超边后其上、下色数的变化.     

一个Steckin加强不等式的两个简易证明

给出了一个加强Steckin不等式的两个简易证明.     

Student Engagement and School Burnout in Finnish Lower-Secondary Schools: Latent Profile Analysis

Self-ratings of behavioural engagement, cognitive engagement and school burnout were used in person-centred analyses to identify latent profiles among 2,485 Finnish lower-secondary school students. Three profiles were identified: high-engagement/low-burnout (40.6% of the sample), average-engagement/average-burnout (53.9%), and low-engagement/high-burnout (5.5%). Another sample of lower-secondary school students was used to validate the 3 profiles. The factors most strongly associated with the high-engagement/low-burnout profile of lower-secondary school students’ were high levels of support from teachers and family, good academic performance, and lack of truancy. The study indicated that teacher and family support and students’ academic achievement are pivotal in understanding student engagement and school burnout.     

复合式训练影响青少年下肢爆发力的meta分析

目的:运用元分析的方法检验复合式训练对青少年下肢爆发力影响的干预效果,检验并提出最优的运动干预方案。方法:运用STATA 15.1和Review Manager 5.3对纳入的10篇文献和301名被试者通过设置抗阻类型、抗阻强度、间歇时间、训练频率和训练周期等5个调节变量进行亚组分析,采用固定效应模型进行整体效应、异质性、发表偏倚性检验。结果:(1)复合式训练对跳跃类运动表现的影响效应量d0.36,对短跑类运动表现的影响效应量d-0.51,两者达到中等效应且具有统计学意义;(2)本研究纳入的10篇文献异质性较低,间歇时间、训练频率和训练周期的对跳跃类和短跑类运动表现影响的效应量有一定差别。结论:(1)复合式训练能够显著提升青少年跳跃类和短跑类运动表现;(2)抗阻训练选择等张收缩、强度70%1RM以下、小于3分钟的间歇时间、在4～8周内选择每周1-2次的复合式训练能够对青少年运动表现有较好的提升;(3)围绕青少年人群开展的复合式训练较为缺乏,后续研究应加强理论与实践研究。     

过早大强度专业化力量训练对足球运动员下肢形态影响的研究

探讨过早大强度专业化力量训练是否对足球运动员下肢形态存在影响,从而科学地进行足球训练。方法:对原陕西省足球队二级以上的运动员25名与体育院系足球学生25名以及普通高校学生25名的下肢形态的相关指标进行对比。实验结果显示:体育院系学生与普通高校学生的下肢形态没有明显差异(P>0.05);原陕西省足球队与普通高校学生有明显差异(p<0.001),足球队运动员的腿部接近于“O”型以及脚尖略微内扣。结论:过早大强度专业化力量足球训练会对运动员下肢形态存在消极的影响。     

正则化方法在非光滑分析中的应用

用正则化方法,借助于数学分析中的凸性判定定理及微分中值定理,证明了非光滑分析中的凸性判定定理及广义微分中值定理     

海南文学的三个关键词

上世纪90年代后,海南和广东合成的诗歌岭南版块在崛起,岭南诗人对诗歌经验贡献了新的价值。这种被称为底层写作的诗歌,表面看来是社会问题,但实质是诗歌从农业题材范畴转化为城市题材写作。韩少功是中国为数不多的令这个时代骄傲的文学大家。韩少功的创作一直深深扎根于乡土,寻找中国人的根,中国文化的根,实际上他一直在不断发展与丰富＂寻根文学＂,也一直在寻找乡土重建之路。作为一个怀疑主义者,他一直怀疑书本的知识,并以个人的实践验证求真,他的努力是为了独自对历史与文明的死结,对文体的边界与语词的丰富性进行最大可能性和最为有效探索与实验。《天涯》是中国稀少的在文坛、学界与思想界最具前沿性和影响力的重要期刊之一。     

Effects of leg dominance on performance of ballet turns (pirouettes) by experienced and novice dancers

Turns (pirouettes) are an important movement in ballet and may be affected by “lateral bias”. This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers.     

田径、举重运动员下肢反应力量能力探析

采用国际上通用的反应力量测试手段和方法，对191名田径、举重运动员和普通人进行了实验测试，通过对测试结果的统计分析，发现：（1）田径、举重运动员下肢反应力量测试结果未能表现出运动项目和竞技水平间的显著性差异；（2）跳深实验中，适宜的下落高度随着性别、运动项目、竞技水平等条件的不同，差异较大，因此，判定适宜的下落高度时，最好具体分析，因人而异；（3）起跳时间对于判定适宜的下落高度也有一定影响，准确的适宜下落高度的判定，对于反应力量的训练具有重要意义。