An ordinary moonlighting activity? Determinants of the provision of private tutoring by Czech schoolteachers

Teacher moonlighting (teachers working other jobs in addition to teaching) may have positive as well as negative implications. In the context of post-socialist countries, the provision of private tutoring is one of the common forms of teacher moonlighting. The aim of the paper is to analyse the prevalence and factors that are associated with a) having a paid job in addition to one’s regular teaching obligations; b) provision of private tutoring among teachers. Results are drawn from a representative sample of 494 Czech teachers of academic school subjects in lower secondary schools who responded to an online questionnaire survey. Male teachers working part-time, with shorter professional experience, higher household financial burden and lower satisfaction with teacher salaries were more likely to moonlight. The provision of private tutoring was only associated with shorter professional experience and the teaching of core subjects, suggesting that Czech teachers’ motivation to provide private tutoring is currently not primarily financial.     

Incremental training intensities increases loads on the lower back of elite female rowers

Lumbar-pelvic kinematics change in response to increasing rowing stroke rates, but little is known about the effect of incremental stroke rates on changes in joint kinetics and their implications for injury. The purpose of this study was to quantify the effects of incremental rowing intensities on lower limb and lumbar-pelvic kinetics. Twelve female rowers performed an incremental test on a rowing ergometer. Kinematic data of rowers’ ankle, knee, hip and lumbar-pelvic joints, as well as external forces at the handle, seat and foot-stretchers of the rowing machine were recorded. Inter-segmental moments and forces were calculated using inverse dynamics and were compared across stroke rates using repeated measures ANOVA. Rowers exhibited increases in peak ankle and L5/S1 extensor moments, reductions in peak knee moments and no change in peak hip moments, with respect to stroke rate. Large shear and compressive forces were seen at L5/S1 and increased with stroke rate (P < 0.05). This coincided with increased levels of lumbar-pelvic flexion. High levels of lumbar-pelvic loading at higher stroke rates have implications with respect to injury and indicated that technique was declining, leading to increased lumbar-pelvic flexion. Such changes are not advantageous to performance and can potentially increase the risk of developing injuries.     

拉萨河下游河谷区三叶草引种品比试验研究

针对拉萨河谷的自然气候条件, 选择了9种三叶草品种进行集中品比试验, 观察各种牧草的越冬率、生育期、高生长速率和产草量等生产形状。结果表明, 拉萨河谷下游河谷区适合引种栽培三叶草，三叶草能够顺利越冬，能够取得与其它地区相似气候条件下的相当产量。在参试品种中，Zgrk8802 红三叶、Beskyd红三叶和Vesna 红三叶是适宜于拉萨河谷下游的优良牧草品种，在越冬率、产草量、生长期和生长速率方面表现都是优良的品种，值得在拉萨河谷下游区推广。     

关于一个平面1-集的不规则性

一个S-集必定是不规则集,除非S是整数.但S是整数的时候这个S-集可能是规则的,也可能是不规则的.为此,利用上密度和下密度来证明一个平面1-集的不规则性.     

ICESat—GLAS测高数据在长江中下游湖泊水位变化监测中的应用

在全球气候变暖的背景下湖泊变化已是国内外地学界关注的环境问题,并日益受到各国政府和研究机构的重视。本文以长江中下游的6个典型湖泊为研究对象,基于2003年-2009年ICESat—GLAS测高数据,采用高斯滤波法对ICESat—GLAS测高数据所对应的回波进行去噪后,用于识别水体与陆地;采用融合算法从LandsatTM影像数据提取湖泊边界;提取湖泊边界内的ICESat—GLAS水位观测值构建了湖泊的年际和年内水位变化,进一步分析了6个湖泊的水位变化时空特征与原因。结果表明：从LandsatTM中提取湖泊边界的精度达到10m,ICESat—GLAS测高数据推算出洪泽湖蒋坝站、洞庭湖城陵矾站、鄱阳湖星子站和都昌站、太湖西山观测站、巢湖闸站和高邮湖高邮站的ICESat测高数据验证的平均精度分别为-3．9cm、-8．3cm、-9．0cm、-2．5cm、-3．1cm和-4．1cm;在整个观测期间,长江中下游流域的湖泊水位呈周期性波动,但较历史观测资料,湖泊平均水位有所降低,且自2006年10月以后三峡工程对洞庭湖的水位调控明显。     

能量耗散对蜿蜒河流分形结构的影响

为了探讨蜿蜒河流平面形态分形结构形成的物理机制,对河流能量耗散进行了定性描述,引入了负熵概念。把河床几何形态划分为若干微观状态,根据这些微观状态的信息量和熵与分形维数的关系探讨河流能量耗散对河床几何形态的影响。结果表明,河床从水流中吸入的负熵越多,其分形维数值越大,河道也愈加蜿蜒曲折。因此,蜿蜒河流平面形态分形结构形成、发育及其演变的物理机制之一可归结为河流系统的耗散性,即河床从水流中吸取负熵的多寡及其变化过程。将上述理论应用于下荆江,计算结果与实际情况比较吻合。     

障碍跑

跨越水池的生物力学分析 在跨越障碍架时,起跨腿在障碍栏架前1．50～1．80米外蹬离地面,上体前倾,微弯曲的摆动腿抬起,用脚的中部踏在横木上。上体继续降低,膝关节接近90°,带动身体重心迅速超越栏架,膝关节保持90°弯曲直到跨离障碍架,一个太小的膝角会妨碍起跨。     

中职信息技术课的情感教学

现代信息技术给我国职业技术教育的腾飞插上了翅膀,但同时信息的大量充斥要求信息技术教师建立新的信息技术观念,加强对信息技术的认识,学会应用和发展信息技术提高教学质量,同时也要关注课堂上的情感教学,给学生学高为师的智慧启迪,身正为范的人格示范,以及学而不厌,诲人不倦的人师精神。     

拓扑空间中的KKM型定理的推广及其应用

在FC-空间的非紧子集上引入了R-SKKM映射,建立了关于紧闭值和转移紧闭值的R-SKKM映射的R-SKKM定理,得到了FC-空间中的极大极小不等式定理和鞍点定理.     

Lie环的Hall幂零性准则

首先仿照幂零群的处理方式，引进幂零Lie环的下中心列，并给出Le环的下中心列商群与Lab的张量积的关系，最后根据群上的Hall幂零性准则，给出了Lie环的Hall幂零性准则，并予以证明．