Kinematic analysis of the shot-put: A method of assessing the mechanical work of the hand action force

The aims of this study were to (1) propose a method for evaluating shot-putters mechanical power, (2) investigate the relationship between mechanical work of hand action force (W_HAF), peak power output (PPO) of different limbs and shot-put performance and (3) show which of these two parameters (W_HAF, PPO) were the most appropriate to characterize the explosive abilities of the shot-putter. Twelve junior right-handed shot-putters, practised glide technique shot-put throwers (personal best?=?13.57 ± 1.72 m), participated in this study. Arm and leg force-velocity tests were performed to measure PPO. Kinematic analysis was conducted during a shot-putting event in regular conditions to quantify the W_HAF at the release moment and shot-put performance. Significant correlations were found between absolute arm and leg PPO with upper and lower muscle volumes (r?=?.67; p?=?.03; r?=?.76; p?=?.01; r?=?.74, p?=?.01; r?=?.65, p?=?.04). Positive relationships were recorded between absolute arm and leg PPO and shot-put performance (r?=?.67, p?=?.02; r?=?.81, p?=?.004, respectively). Shot-put performance was also closely related to the W_HAF (r?=?.93, p?=?.0001) and release velocity parameter (r?=?.86, p?=?.001). The present results confirm that force-velocity test and W_HAF constitute useful tools for assessing mechanical power in throwing. The W_HAF could be considered as more suitable than force-velocity test.     

人体器官芯片

人体器官芯片是一门新兴的前沿科学技术,也是一门典型的多学科交叉汇聚技术,对人类健康和生物产业发展具有重要战略意义,吸引了来自政府、科学界和产业界的关注,被2016年达沃斯世界经济论坛列为"十大新兴技术"之一。人体器官芯片指的是一种在载玻片大小芯片上构建的器官生理微系统,包含有活体细胞、组织界面、生物流体和机械力等器官微环境关键要素。它可在体外模拟人体不同组织器官的主要结构功能特征和复杂的器官间联系,用以预测人体对药物或外界不同刺激产生的反应,在生命科学和医学研究、新药研发、个性化医疗、毒性预测和生物防御等领域具有广泛应用前景。文章概述性介绍了人体器官芯片的起源、国际发展态势和研究进展,并对其面临的挑战和未来发展趋势予以展望。     

中药靶向制剂研究进展

靶向制剂可以选择性地作用于靶器官、靶组织、靶细胞或细胞内。但中药靶向制剂还处在基础研究阶段,回顾近年来中药靶向制剂的研究,指出中药靶向制剂能够成为中药制剂的一个重要发展方向。     

关于中强震前的应变加速释放现象

针对中强地震前是否会出现地震活动性增强现象的问题,研究了1990～2003年中国MS70以上地震.对于同一个地震事件,考虑了多个不同的时间和空间尺度,结果表明,中强震前的地震活动性远比用简单的应变加速释放模型来描述复杂得多.因此,将应变加速释放模型应用于地震危险性估计,仍需做更多的研究.     

A synthesis of research on effectiveness of school-based drug prevention programmes / Claves de eficacia de los programas de prevención de consumo de sustancias en el contexto escolar: una meta-revisión

Abstract

Relevant information on effectiveness of school-based drug prevention programmes is available. Despite this, there is still contradictory evidence that makes it necessary to continue to shed light on this issue. Based on a synthesis research method, the aim of this study was to determine the relevant variables that enhance the efficacy of these programmes and to determine the weight of their empirical evidence. Furthermore, several features of the evaluation designs whose variables had been proven effective were examined. A systematic review of periodical literature was conducted, which led us to extract 1,622 papers, of which 17 studies were analysed. An in-depth analysis of these publications led us to identify 29 key variables associated with the efficacy of the programme, which were ranked according to the weight of their empirical evidence. Moreover, the characteristics of the studies included in the review highlighted the need to improve the rigorousness and quality of the evaluation designs in this field.     

高职“药物检测技术”项目课程的开发与实践

基于工作过程系统化的职教理论,坚持学科本位向学生能力本位转化的教改思路,应用文献查阅、企业访谈、实践总结的研究方法。就项目课程开发的步骤、项目课程在教学实践中实施的过程、项目课程的教学评价体系、项目课程教学资源开发等问题,对高职“药物检测技术”课程进行项目课程开发。实践证明,项目教学课程模式的应用可以改变学生学习“药物检测技术”兴趣不足的现状,可以加强培养学生分析问题和解决问题能力的培养,是目前课改思路中较为有效的一种途径。     

Efficient interlayer charge release for high-performance layered thermoelectrics

Many layered superlattice materials intrinsically possess large Seebeck coefficient and low lattice thermal conductivity, but poor electrical conductivity because of the interlayer transport barrier for charges, which has become a stumbling block for achieving high thermoelectric performance. Herein, taking BiCuSeO superlattice as an example, it is demonstrated that efficient interlayer charge release can increase carrier concentration, thereby activating multiple Fermi pockets through Bi/Cu dual vacancies and Pb codoping. Experimental results reveal that the extrinsic charges, which are introduced by Pb and initially trapped in the charge-reservoir [Bi₂O₂]²⁺ sublayers, are effectively released into [Cu₂Se₂]²⁻ sublayers via the channels bridged by Bi/Cu dual vacancies. This efficient interlayer charge release endows dual-vacancy- and Pb-codoped BiCuSeO with increased carrier concentration and electrical conductivity. Moreover, with increasing carrier concentration, the Fermi level is pushed down, activating multiple converged valence bands, which helps to maintain a relatively high Seebeck coefficient and yield an enhanced power factor. As a result, a high ZT value of ∼1.4 is achieved at 823 K in codoped Bi_0.90Pb_0.06Cu_0.96SeO, which is superior to that of pristine BiCuSeO and solely doped samples. The present findings provide prospective insights into the exploration of high-performance thermoelectric materials and the underlying transport physics.     

Identifying some factors that might predispose drug abuse among learners in a South African township school

Abstract

This study inquires into some of the factors that might predispose the use and abuse of drugs among secondary school learners in a township school. The objective of this research is to identify these factors and to offer a few suggestions on how the abuse may be prevented. A quantitative research strategy is used and a document analysis technique has been incorporated to collect the data. Various hypotheses are stated. The independent variables used are: gender; age group; educational category; distance from school; and caregiver. The dependent variables used are: alcohol abuse; marijuana abuse; cigarette smoking; other drug abuse; total number of abuses; and outcomes at school. Statistically significant relationships are found between the following variables: distance from school and cigarette smoking; distance from school and other drug abuse; caregiver and marijuana abuse; and caregiver and total number of abuses.     

毒品及艾滋病致孤儿童集中教育救助实践探索——以边疆少数民族地区某小学为例

云南省某边疆少数民族地区,项目县将部分义务教育阶段的毒品及艾滋病致孤学生全免费集中于县直属某小学的各班级,通过社会各界捐助和学校经费倾斜,解决他们的学习、生活及医疗等问题。实施在校期间由学校集中救助教养、寒暑假期由乡镇政府接回交给原代理监护人看管的方式,历经四年多的实践探索,初步形成学校集中救助毒品及艾滋病致孤儿童的特色教育救助模式。     

化学实验室危险、剧毒、易制毒化学品的管理异同

通过对高等学校化学实验室危险化学品、剧毒化学品、易制毒化学品的采购、运输、库房保管、领取、使用等方面的管理异同进行比较,保证剧毒化学品和易制毒化学品的合法使用,消除安全隐患,提高高等学校化学实验室危险化学品、剧毒化学品、易制毒化学品的安全管理水平.