Abstract In this study, we wished to investigate the factors that determine the direction of the spin axis of a pitched baseball. Nineteen male baseball pitchers were recruited to pitch fastballs. The pitching motion was recorded with a three-dimensional motion analysis system (1000 Hz), and the orientations of the hand segment in a global coordinate system were calculated using Euler rotation angles. Reflective markers were attached to the ball, and the direction of the spin axis was calculated on the basis of their positional changes. The spin axis directions were significantly correlated with the orientations of the hand just before ball release. The ball is released from the fingertip and rotates on a plane that is formed by the palm and fingers; the spin axis of the ball is parallel to this plane. The lift force of the pitched baseball is largest when the angular and translational velocity vectors are mutually perpendicular. Furthermore, to increase the lift forces for the fastballs, the palm must face home plate. 相似文献
Abstract The aim of this study was to assess the capability of the 3dNX? accelerometer to predict energy expenditure in two separate, free-living cohorts. Twenty-three adolescents and 14 young adults took a single dose of doubly labelled water and wore a 3dNX? activity monitor during waking hours for a 10-day period while carrying out their normal routines. Multiple linear regression with backward elimination was used to establish the strength of the associations between various indices of energy expenditure, physical activity counts, and anthropometric variables. 3dNX? output accounted for 27% and 35% of the variance in the total energy expenditure of the adolescent and young adult cohort, respectively. The explained variance increased to 78%, with a standard error of estimate of 7%, when 3dNX? output was combined with body composition variables. The 3dNX? accelerometer can be used to predict free-living daily energy expenditure with a standard error of estimate of 1.65 MJ in adolescents and 1.52 MJ in young adults. The inclusion of anthropometric variables reduces the error to approximately 1 MJ. Although it remains to cross-validate these models in other populations, early indications suggest that the 3dNX? provides a useful method of predicting energy expenditure in free-living individuals. 相似文献
Recent research suggests that Muslim boys have become the ‘New Folk Devils’ of British education, who are characterised by resistance to formal education, especially at secondary level, and under-achievement. Since the 1990s, British Muslim boys would appear to have become increasingly alienated from compulsory schooling, especially in the humanities subjects which lack obvious instrumental value.
This mixed-methods study of the performance of 295 secondary school British Muslim boys in their compulsory school history provides evidence which interrupts this narrative of the academic under-achievement and educational dis-engagement of Muslim boys, especially in the humanities subjects. When viewed through the prism of a laminated, non-reductive model of educational success, this indicative sample of British Muslim boys could be considered to have had significant success at a traditional humanities subject such as history intellectually, spiritually, emotionally, instrumentally and civically.
This paper therefore proposes that history can provide a vital meaning-making tool to generate the success of Muslim boys in a variety of significant dimensions both in and out of school. It suggests how history can be more fully and effectively harnessed by teachers, parents and policy-planners to encourage internal integration and external social engagement in British Muslim pupils. 相似文献
AbstractIn South Africa the education system for black children is fraught with problems. These problems are the direct result of apartheid and have been compounded by poverty and illiteracy. In this article the problem of poorly qualified or unqualified teachers is discussed especially with regard to the teaching of map skills to children in their fifth school year. The project team needed to develop affordable materials which could be used in large classes by teachers after a very short period of training. Books and other materials which are available commercially were examined, but for various reasons were found to be unsuitable for local conditions. After determining the extent of the problem, the project team followed a grassroots process of developing a flip chart which teachers learnt to use with confidence and which enabled pupils to master the concepts and skills necessary for understanding a map. 相似文献
This paper describes the user-focused approach to information skills at MMU Library. It covers the following cycle: identifying training needs at three levels (organisation, group and individual); developing a training strategy and materials; marketing information skills within MMU. Specifically, it describes how we went about discovering what our users wanted, creating and delivering what they needed, and how we ‘sold’ it back to them. 相似文献
ABSTRACT The library implemented a new service model focusing on improved expertise, efficiency, and morale during a period of leadership change and workforce reduction. Implementation of a Disney-type service model helped identify skill sets for departmental reorganization. Hiring methods targeted candidates that best fit expectations for the changing needs of the library. New service goals led to improved skills, better personnel matches, and increased dedication. Results included several University Library monetary awards, as well as patron comments that directly related to the changes. The goal-oriented plan implemented by the library addressed a work-force reduction and created a new, highly appreciated service model. 相似文献
An academic medical library expanded its iPad loan service to multiple campus libraries and conducted an assessment of the service. iPads loaded with medical and educational apps were loaned for two-week checkouts from five library campus locations. Device circulation statistics were tracked and users were invited to complete an online survey about their experience. Data were gathered and analyzed for 11 months. The assessment informed the library on how best to adapt the service, including what resources to add to the iPads, and the decision to move devices to campuses with more frequent usage. 相似文献
Written in response to criticism of our work by Fouad Abd-El-Khalick, this position paper reaffirms and reinforces our position about the need to broaden and enrich the scope of nature of science (NOS) oriented curricula by exposing students to the voices of practising scientists. While Abd-El-Khalick's motivation for promoting the so-called consensus view of NOS is rooted in issues of assessment (or ‘benchmarking', as he calls it), we argue that the major reason for teaching about NOS is its contribution to what Shen calls civic and cultural scientific literacy. We are critical of the consensus view for its philosophical naivety, failure to reflect contemporary scientific practice and potential for confusing students, and we re-state our view that it is important to expose students to a diversity of practice among the sub-disciplines of science. We argue that richer NOS understanding and a more authentic view of scientific practice can be achieved through direct and indirect contact with scientists at the cutting edge of research and development, which we characterise as learning about scientists, learning from scientists and learning with scientists. 相似文献