Landing techniques in volleyball     

Lobietti R  Coleman S  Pizzichillo E  Merni F 《Journal of sports sciences》2010,28(13):1469-1476

Knee injuries such as anterior cruciate ligament lesions and patellar tendonitis are very frequent in volleyball, and are often attributed to micro traumas that occur during the landing phase of airborne actions. The aim of the present study was to compare different jumping activities during official men's and women's volleyball games. Twelve top-level matches from the Italian men's and women's professional leagues were analysed. The jumps performed during the games were classified according to the landing technique used by the player (left or right foot or both feet together), court position, and ball trajectory. Chi-square analyses were performed to detect differences in landing techniques between the sexes, court positions, and trajectories when serving, attacking, blocking, and setting. Significant differences (P?相似文献   

Education in small states: policies and priorities     

Simon McGrath 《比较教育学》2014,50(4):509-510

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Effect of verbal instructions and image size on visual search strategies in basketball free throw shooting     

Al-Abood SA  Bennett SJ  Hernandez FM  Ashford D  Davids K 《Journal of sports sciences》2002,20(3):271-278

We assessed the effects on basketball free throw performance of two types of verbal directions with an external attentional focus. Novices (n = 16) were pre-tested on free throw performance and assigned to two groups of similar ability (n = 8 in each). Both groups received verbal instructions with an external focus on either movement dynamics (movement form) or movement effects (e.g. ball trajectory relative to basket). The participants also observed a skilled model performing the task on either a small or large screen monitor, to ascertain the effects of visual presentation mode on task performance. After observation of six videotaped trials, all participants were given a post-test. Visual search patterns were monitored during observation and cross-referenced with performance on the pre- and post-test. Group effects were noted for verbal instructions and image size on visual search strategies and free throw performance. The 'movement effects' group saw a significant improvement in outcome scores between the pre-test and post-test. These results supported evidence that this group spent more viewing time on information outside the body than the 'movement dynamics' group. Image size affected both groups equally with more fixations of shorter duration when viewing the small screen. The results support the benefits of instructions when observing a model with an external focus on movement effects, not dynamics.  相似文献   

Visual search and biological motion perception in tennis   总被引：1，自引：0，他引：1  

Ward P  Williams AM  Bennett SJ 《Research quarterly for exercise and sport》2002,73(1):107-112

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Coming in from the Cold? Further education and training in South Africa     

Simon McGrath 《Compare》2000,30(1):67-84

As South Africa enters the Mbeki Presidency so the fortunes of the country are thrown into sharp relief. One of the central elements determining South Africa's short- to medium-term future will be the success of educational transformation, particularly when it is directed to addressing issues of equity and economic development. This paper explores the 1998 reforms of the further education and training system in the context of broader questions of educational and economic transformation in South Africa.  相似文献   

Social and interactional practices for disseminating current awareness information in an organisational setting     

Simon Attfield  Ann Blandford  Stephann Makri 《Information processing & management》2010

Current awareness services are designed to keep users informed about recent developments based around user need profiles. In organisational settings, they may operate through both electronic and social interactions aimed at delivering information that is relevant, pertinent and current. Understanding these interactions can reveal the tensions in current awareness dissemination and help inform ways of making services more effective and efficient. We report an in-depth, observational study of electronic current awareness use within a large London law firm. The study found that selection, re-aggregation and forwarding of information by multiple actors gives rise to a complex sociotechnical distribution network. Knowledge management staff act as a layer of “intelligent filters” sensitive to complex, local information needs; their distribution decisions address multiple situational relevance factors in a situation fraught with information overload and restrictive time-pressures. Their decisions aim to optimise conflicting constraints of recall, precision and information quantity. Critical to this is the use of dynamic profile updates which propagate back through the network through formal and informal social interactions. This supports changes to situational relevance judgements and so allows the network to ‘self-tune’. These findings lead to design requirements, including that systems should support rapid assessment of information items against an individual’s interests; that it should be possible to organise information for different subsequent uses; and that there should be back-propagation from information consumers to providers, to tune the understanding of their information needs.  相似文献   

Initiating private-collective innovation: The fragility of knowledge sharing     

Simon Gächter 《Research Policy》2010,39(7):893-906

Incentives to innovate are a central element of innovation theory. In the private-investment model, innovators privately fund innovation and then use intellectual property protection mechanisms to appropriate returns from these investments. In the collective-action model, public subsidy funds public goods innovations, characterized by non-rivalry and non-exclusivity in using these innovations. Recently, these models have been compounded in the private-collective innovation model where innovators privately fund public goods innovations. Private-collective innovation is illustrated in the case of open source software development. This paper contributes to the work on this model by investigating incentives that motivate innovators to share their knowledge in an initial situation, before there is a community to support the innovation process. We use game theory to predict knowledge sharing behavior in private-collective innovation, and test these predictions in a laboratory setting. The results show that knowledge sharing is a coordination game with multiple equilibria, reflecting the fragility of knowledge sharing between innovators with conflicting interests. The experimental results demonstrate important asymmetries in the fragility of knowledge sharing and, in some situations, more knowledge sharing than theoretically predicted. A behavioral analysis suggests that knowledge sharing in private-collective innovation is not only affected by material incentives, but also by social preferences such as fairness. The results offer general insights into the relationship between incentives and knowledge sharing and contribute to a better understanding of the initiation of private-collective innovation.  相似文献   

Can cities shape socio-technical transitions and how would we know if they were?   总被引：2，自引：0，他引：2  

Mike Hodson  Simon Marvin 《Research Policy》2010,39(4):477-485

This paper asks two - relatively simple - questions: can cities shape socio-technical transitions? And how would we know if they were? There are three key objectives. The first of these is to set out emerging, and in our view, convincing evidence, that large world cities have political aspirations to develop purposive and managed change in the socio-technical organisation of infrastructure networks that can be characterised as ‘systemic’ transitions. The second objective is conceptual in orientation and seeks to address how we understand transitions at the scale of the city, the role of ‘the city’ in undertaking transitions, and review both the strengths and shortcomings of the multi-level perspective (MLP) on socio-technical transitions in addressing this. The third objective is to identify what an urban transition would look like, and then constructs a new framework to conceptualise and research urban transitions. The paper then summarises the key aspects and implications of our argument.  相似文献   

A material perspective on 18th-century chemistry     

Jonathan Simon 《Metascience》2010,19(1):71-73

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Building Future Directions for Teacher Learning in Science Education     

Kathy Smith  Simon Lindsay 《Research in Science Education》2016,46(2):243-261

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