Variable training: effects on velocity and accuracy in the tennis serve

Abstract

Variable practice has been shown to be an effective strategy to improve open motor skills. However, the usefulness of this procedure in closed motor skills remains controversial. The following study has the objective of analysing the effects of variability practice in the improvement of a closed skill. The skill studied has been the tennis serve. Thirty young tennis players (13 ± 1.52 years), divided in two groups, took part in this study. One group practiced in variable conditions and the other group in consistency conditions. Both groups performed 12 training sessions (60 serves/session). The variable practice group improved their accuracy significantly compared with the consistency group (F_3.25 = 3.078; P = 0.035). The velocity of serve increased after training in both groups (F_3.25 = 15.890; P = 0.001). The practice in variable conditions seems to be effective in improving the performance of the tennis serve.     

初中学生冰上运动安全知识、技能实验干预研究

运用知识讲座、宣传手册、知识竞赛等方式对初一被试学生进行冰上运动安全实验干预,使用自编问卷评估实验前后被试学生冰上运动安全知识技能掌握情况,使用SPSS17．0对获得数据进行自身对照T检验。结果表明：学生通过知识讲座、技能培训、安全手册学习和知识竞赛等干预形式掌握了冰上运动安全知识、安全防护技能和运动损伤急救知识,说明实验干预内容、方法有效可行。     

Exploring the Causal Effect of Interpretation Bias on Attachment Expectations

Attachment theory implies that children's inclination to interpret attachment figures behavior as supportive and available causally influences children's trust in their attachment figure's availability. An experiment was conducted to test whether training children (8–12 years old) to interpret ambiguous interactions with their mothers in a more secure way increases their trust in their mother's availability. Participants (N = 49) were randomly assigned to either a secure condition to train children to interpret their mother's behavior as supportive or a neutral placebo condition, where interpretations were unrelated to maternal support. Results supported the hypothesis: After the secure training, children interpreted maternal behavior more securely and trusted more in her availability. This suggests that attachment‐related processing biases causally affect attachment expectations.     

Exploring the potential impact of reciprocal peer tutoring on higher education students’ metacognitive knowledge and regulation

It is widely recognized that metacognition is an important mediator for successful and high-level learning, especially in higher education. Nevertheless, a majority of higher education students possess insufficient metacognitive knowledge and regulation skills to self-regulate their learning adequately. This study explores the potential of reciprocal peer tutoring to promote both university students’ metacognitive knowledge and their metacognitive regulation skills. The study was conducted in a naturalistic higher education setting, involving 67 students tutoring each other during a complete semester. A multi-method pretest–posttest design was used combining a self-report questionnaire, assessing students’ metacognitive knowledge and their perceived metacognitive skilfulness, with the analysis of think-aloud protocols, revealing students’ actual use of metacognitive strategies. Results indicate no significant pretest to posttest differences in students’ metacognitive knowledge, nor in their perception of metacognitive skill use. In contrast, significant changes are observed in students’ actual metacognitive regulation. At posttest, students demonstrate significantly more frequent and more varied use of metacognitive regulation, especially during the orientation, monitoring, and evaluation phases. Furthermore, our findings point to an increase in more profound and higher-quality strategy use at posttest.     

Exploring features for the automatic identification of user goals in web search

Queries submitted to search engines can be classified according to the user goals into three distinct categories: navigational, informational, and transactional. Such classification may be useful, for instance, as additional information for advertisement selection algorithms and for search engine ranking functions, among other possible applications. This paper presents a study about the impact of using several features extracted from the document collection and query logs on the task of automatically identifying the users’ goals behind their queries. We propose the use of new features not previously reported in literature and study their impact on the quality of the query classification task. Further, we study the impact of each feature on different web collections, showing that the choice of the best set of features may change according to the target collection.     

猪八戒形象简论

从猪八戒这个貌似滑稽的角色出发 ,探讨《西游记》塑造这个形象的命意 :只要皈依佛门 ,终能得正果 ,为凡夫俗子树一个榜样。并对此命意予以批判     

日本大学招生考试制度的多样化

日本的大学招生考试经过多次改革，形成了“大学入学考试中心考试”和各大学的个别考试并用的模式。在这一模式中，多样化是其主要特征之一，主要表现为考试机会的复数化、选拔方法的多样化、评价尺度的多元化。     

‘Trying to find the extra choices’: migrant parents and secondary school choice in Greater Manchester

This article, based on qualitative research in Greater Manchester, examines the experience of migrants in navigating the education system, and in particular in choosing secondary schools for their children. There has been extensive research on the process of choosing schools since the policy reforms of the 1980s, but none has examined how the process of choosing a secondary school is impacted by the material and affective impact of migration. The article argues that migrants’ experience is embedded in gendered, classed and racialised processes and that, despite the heterogeneity of the category, migrants often face particular barriers in negotiating the school system. Nonetheless it also explores the importance put on education by the migrants who were interviewed and the active labour they engage in to try and achieve the best results for their children.     

Role of working memory in explaining the performance of individuals with specific reading comprehension difficulties: A meta-analysis

It is well established that working memory is related to reading comprehension ability. However, its role in explaining specific reading comprehension difficulties is still under debate: the issue mainly concerns whether the contribution of working memory is dependent on task modality (verbal tasks being more predictive than visuo-spatial tasks) and/or on the attentional control implied in working memory tasks (tasks requiring storage/manipulation being more predictive than storage-only tasks, regardless of task modality). Meta-analysis is used here to examine the relevance of several working memory measures in distinguishing between the performance of poor and good comprehenders in relation to the modality of the working memory task, and the involvement of controlled attention required by such a task. Our results demonstrate that memory tasks that are demanding in terms of attentional control and that require verbal information processing are best at distinguishing between poor and good comprehenders, suggesting that both domain-specific factors as well as general factors of working memory contribute to reading comprehension performance. The implications for different models of working memory in relation to reading comprehension are discussed.     

The Impact of Institutional Context,Education and Labour Market Policies on Early School Leaving: a comparative analysis of EU countries

This article presents a comparative analysis of the determinants of early school leaving (ESL) at the country level. We decompose ESL rates into two components: a ‘primary’ rate reflecting unqualified school leaving from initial education, and a second component accounting for early school leavers who participate in training programmes. Both may be influenced by structural and policy determinants. We examine how the ESL rate is affected by macro-economic and social context variables such as GDP/capita, growth, poverty, and youth unemployment, as well as system characteristics of the education system (such as legal school leaving age, grade retention, early tracking, and size of vocational education) and the labour market and social protection systems (minimum wages, unemployment insurance).