Reliability and validity of field-based fitness tests in youth soccer players

This study aimed to establish between-day reliability and validity of commonly used field-based fitness tests in youth soccer players of varied age and playing standards, and to discriminate between players without (“unidentified”) or with (“identified”) a direct route to professional football through their existing club pathway. Three-hundred-and-seventy-three Scottish youth soccer players (U11–U17) from three different playing standards (amateur, development, performance) completed a battery of commonly used generic field-based fitness tests (grip dynamometry, standing broad jump, countermovement vertical jump, 505 (505COD) and T-Drill (T-Test) change of direction and 10/20 m sprint tests) on two separate occasions within 7–14?days. The majority of field-based fitness tests selected within this study proved to be reliable measures of physical performance (ICC?=?0.83–0.97; p?p?2 (7)?=?101.646, p?相似文献   

干旱区绿洲土地利用景观空间格局动态变化研究——以渭干河—库车河三角洲绿洲为例

渭干河—库车河三角洲绿洲地处世界第二大沙漠塔克拉玛干沙漠的北缘，该绿洲现已成为新疆主要的农业区和棉花基地。但随着经济的快速发展，土地资源开发强度开始加大。本研究利用1989年和2001年的遥感影像数据，借助RS和GIS技术，运用景观生态学原理，通过计算多样性指数、优势度指数、分离度指数、均匀度指数、破碎度指数等指标，对渭干河—库车河三角洲绿洲的景观格局及土地利用变化进行动态分析，得出：多样性指数从1.304降低到1.190，优势度指数从0.305升高到0.419，均匀度指数从0.8104降低到0.7396，破碎度指数从0.0177升高到0.0225，并揭示出土地利用类型三增两减(盐碱地、水体、红柳增加，绿洲、荒地减少)的变化特征。同时，利用SPSS软件对土地利用变化的驱动机制进行了分析，结果表明：人口，经济，政策因子仍然是占主导地位的。     

基于GIS的干旱区土壤盐渍化敏感性评价——以渭干河-库车河三角洲绿洲为例

本文根据研究区域的自然环境特征,在GIS支持下,通过单因子分析和多因子综合评价相结合,对研究区域土壤盐渍化敏感性进行了评价,明确了土壤盐渍化敏感性分布规律及其地域差异。结果表明,研究区域土壤盐渍化危险性较严重—敏感性区域主要以中度敏感性、轻度敏感性为主,其中土壤盐渍化重度敏感区面积占绿洲总面积的15%,中度敏感区占31%,轻度敏感区占30%;不敏感区面积占35%;从整个研究区来看,盐渍化敏感性的分布呈现出以下特点：一是盐渍化危险性区域,尤其是中度、重度敏感区域呈大面积区域性分布,轻度敏感性区域呈片状或斑点状断续分布;二是盐渍化危险性东部高于西部,南部高于北部的趋势。     

纹理谱直方图与潜在语义标引在图像检索中的应用

提出一种新的描述局域像素灰度变化的纹理谱方法,并将该方法抽取出的纹理谱直方图特征用于图像检索。实验表明该特征计算简单,检索结果较好,是一种适于图像检索的底层特征。同时将应用于文本检索领域的潜在语义标引方法用于图像检索,并提出了一种计算近似矩阵秩的方法。实验结果显示使用该方法可以分析图像中存在的隐含语义结构,并提高检索效率。     

Technique and timing in women's inward two and one half somersault tuck (405C) and the men's inward two and one half somersault pike (405B) 3 m springboard dives

The purpose of this study was to compare the inward two and one half somersault dive in a tuck position (405C) performed by females (n = 22) and the inward two and one half somersault dive in a pike position (405B) performed by males (n = 24) to determine changes required by females to successfully perform 405B. Key performance variables in inward dives were also compared to those of backward dives. Video data of the dives performed at the 1999 FINA World Diving Cup were captured and digitized to obtain times and postures of the divers at specific events including takeoff and entry. Estimates of flight height and mass-normalised work done on the springboard were obtained from flight times. Some females worked the springboard strongly enough to generate sufficient height and rotation to perform 405B. Males performed 405B comfortably because they achieved better height and rotation than the females. A comparison of backward and inward dives revealed that divers are able to attain greater height in backward dives than inward dives.     

论双重乐感体系下《维吾尔民歌元素与风格训练》课程的构建

《维吾尔民歌元素与风格训练》课程是"双重乐感理论与实践"的重要组成部分。该课程分为民歌语言、元素与风格和演唱实践三个子课程,每个子课程又分别由元素、乐律、乐调、音列和节奏等具体内容构成。教师要想教授好这些课程,除了熟练教学内容外,还要掌握一些重要的教学策略,比如:了解维吾尔民歌形成的历史背景,帮助学生对维吾尔民歌风格形成全面认知;运用典型的维吾尔舞蹈,调动学生的内在律动;民族乐器伴奏贯穿于学习始终,培养学生的音乐感知力;注重培养学生理解民歌的曲调与歌谣的诗韵关系的能力;通过聆听训练学生对民歌整体风格把握的能力。这些策略有助于学生更快、更好地掌握民歌风格,最终成为真正拥有双重音乐能力的人。     

试探蒙古族民间传说中的哲学思想

史诗《江格尔》不仅反映出古代蒙古族朴素唯物主义和自然辩证法的思想,还包含着人生观,社会历史观等进代论的思想。     

The Western Primary School 'Quiet Room' Project

There has been a great deal of interest recently in the development of more 'nurturing' environments in mainstream primary schools. This interest has been reflected in a series of articles published in the pages of this journal. In this paper, Angus King, headteacher of Western Primary School, a performance management consultant, a threshold assessor and a teacher trainer, with Zara Chantler, Key Stage 1 leader and SENCo at Western, describe the Western 'Quiet Room' project, set up in 1999 as a response to the needs of pupils experiencing social, emotional and behavioural problems. The Quiet Room was designed to provide a nurturing environment in a dedicated space away from the classroom. In this way, argue King and Chantler, a child's emotional needs can be explored, on a one–to–one basis where appropriate, in a safe and supportive setting. The results to date are positive and there is real potential for the scheme to be extended.