Inter-participant variability in daily physical activity and sedentary time among male youth sport footballers: independent associations with indicators of adiposity and cardiorespiratory fitness

Participation in youth sport is assumed to promote and contribute towards more physically active lifestyles among children and adolescents. The aim of this study was to examine inter-participant variability in objectively measured habitual physical activity (PA) behaviours and sedentary time among youth sport participants and their implications for health. One-hundred-and-eighteen male youth sport footballers (Mean ± s = 11.72 ± 1.60) wore a GT3X accelerometer for 7 days. Average daily PA [min · day^?1, in light (LPA), moderate (MPA), vigorous (VPA) and combined moderate-to-vigorous (MVPA)] and sedentary time were calculated. Participants’ body mass index adjusted for age and sex (BMI–standard deviation score), per cent body fat (BF%), waist circumference and cardiorespiratory fitness were assessed. Results revealed that variability in daily PA behaviours and sedentary time (min · day^?1) was associated with BMI–standard deviation score [VPA (?), MVPA (?)], BF% [sedentary time (+), VPA (?), MVPA (?)], waist circumference [sedentary time (+), LPA (?)] and cardiorespiratory fitness [sedentary time (?), MPA (+), VPA (+), MVPA (+)]. Whilst sedentary time and MVPA were not related to health outcomes independent of one another, associations with markers of adiposity and cardiorespiratory fitness were stronger for sedentary time. Sedentary time was also significantly positively related to waist circumference independent of VPA. Results demonstrate inter-participant variability in habitual PA and sedentary time among youth sport participants which holds implications for their health. Thus, promoting PA and, in particular, reducing sedentary time may contribute towards the prevention of adverse health consequences associated with a physically inactive lifestyle for children and adolescents active in the youth sport context.     

Understanding Differences in Academic Effectiveness: Practitioners’ Views∗

As part of a large‐scale study of the ability of 94 secondary schools to promote academic achievement, case studies of six outlier schools were conducted and headteachers (principals) and their deputies were questioned about the processes of effectiveness. The analysis of their responses ‐ grouped by the performance of their school (measured by value added analyses of three years of public examination results) as effective, ineffective or mixed ‐ reveals considerable support for previously cited characteristics of effective schooling. Despite the limitations imposed by a reliance on the use of retrospective accounts, the study takes forward the field of school effectiveness in its search for generalisable findings and coherent theory.

     

城市社会空间形态的转变与农民市民化

农民市民化是城市化整体进程中最为深刻的层面。上世纪90年代中期以来,随着我国大中城市城乡一体化发展的加快,在一些发达地区出现了景观城市化与农民市民化相脱节的现象,使农民市民化问题的重要性更为凸显。实际上,城市社会空间形态的转变与农民市民化之间具有十分密切的相互依存的关系．正是城乡一体化的发展,不断地促进社会空间格局从分散布局到空间体系的构筑、社会空间流动从地域凝固到空间开放的催化、社会空间治理从政区分割到区域联动的形成;而这一系列重大变化正深刻地表明,农民市民化既是城乡一体化发展的社会进程,同时也是城市形态变迁的空间过程。     

史怀哲、敬畏生命与世界宗教

史怀哲“敬畏生命”的生态伦理学认为一切生命不仅有价值,而且是神圣的.他把这看成是逻辑和思想的必然结果.他强调人类与其他各种生命形式之间休戚与共的关系,他所遵循的“不伤害生命”或“善待其他生命”等基本原则,与世界上其他宗教和文化的根本信念是一致的,如基督教、印度教、佛教、儒家和道家等,尽管理论上稍有不同.史怀哲还以自己一生都在非洲热带丛林里进行医疗事业的传奇经历,亲自实践着他的这一生命伦理理念,全身心地、多方面地努力追求敬畏生命的道德生活.     

Accuracy of a Perspective Control Lens

Abstract

The contextual interference (CI) effect has been replicated many times since its first demonstration by Shea and Morgan (1979) in the motor learning domain (see Brady, 1998; Magill&;Hall, 1990). The CI effect is characterized by the observation that experiencing greater interference during acquisition is detrimental to immediate performance but enhances delayed performance as measured on retention or transfer tests. High CI is most often created by random practice in which the learning of multiple tasks occurs in a single training. In contrast, low CI is frequently created by using a blocked practice format in which all the practice trials of one task are completed before another task is introduced. One theoretical account that has been forwarded to account for the CI effect is labeled the action plan reconstruction hypothesis (Lee&;Magill, 1983, 1985). This position intimates that before a movement occurs an “action plan” must be prepared. In blocked practice, a previously prepared “action plan” is readily available from trial to trial, but it suffers from lack of attention on trials following initial retrieval from working memory. In random practice, however, each time a task must be executed a “reconstruction” of the action plan must be processed, because the interchange of information from trial to trial never allows the same information to remain in working memory for an extended amount of time. Presumably, the additional trial-to-trial preparation used by the random practice participant during practice results in a more resilient memory representation that better supports long-term recall efforts compared to their blocked practice counterparts.     

Unpacking Our Academic Suitcases: The Inner Workings of Our Feminist Research Group

In this paper we focus on the lived experiences of multidisciplinary scholars as we navigated and coalesced into a productive, interdisciplinary collaboration. We pull from our foundations in feminist methodology and provide excerpts from personal journals and reflexive group interviews to provide a behind-the-scenes account of the inner workings of a feminist research group. While sharing a common research goal, each member negotiated her personal, conceptual, and epistemological stances as we produced an effective, interdisciplinary pastiche. Throughout this process, we worked to create a non-hierarchical atmosphere, continuously and ethically questioned our methods, and incorporated reflexivity in the research processes. In addition to sharing our past experiences, we note challenges we encountered and offer practical suggestions based on the lessons we learned through this collaboration.     

企业簇群、竞争优势与企业竞争战略

竞争力是竞争优势和竞争战略的逻辑起点 ,动态地考察企业竞争力的来源有利于科学地把握企业簇群的竞争力和竞争优势的形成机制。企业簇群能够通过地理集中、产业组织优化和群体协同效应获得竞争力和竞争优势的提升 ,但只有确立企业竞争战略观 ,才能使企业持续地获得和保持竞争优势