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This paper considers the relationship between stress and cognitive functioning and discusses some of the concepts and methods that may be adopted to examine the relationship between stress and sports performance. It considers only that literature that may be relevant to, or furthers, the understanding of sports performance under competitive stress. One of the most popular approaches has been to explain the relationship in terms of the unidimensional inverted-U hypothesis. The validity of this approach to explaining sports performances in specific situations is discussed and it is generally concluded that the inverted-U hypothesis is too vague and simplistic. The discussion considers multidimensional approaches and discusses the suitability and implications of some more recent and more complex models of stress and performance which are now available in the psychological literature. It is concluded that the relationship between stress and sports performance is an extremely complex one and involves the interaction between the nature of the stressor, the cognitive demands of the task being performed and the psychological characteristics of the individuals performing it. 相似文献
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We describe a microfluidic device for on-chip chemical processing, such as staining, and subsequent washing of cells. The paper introduces “separator walls” to increase the on-chip incubation time and to improve the quality of washing. Cells of interest are concentrated into a treatment stream of chemical reagents at the first separator wall for extended on-chip incubation without causing excess contamination at the output due to diffusion of the unreacted treatment chemicals, and then are directed to the washing stream before final collections. The second separator wall further reduces the output contamination from diffusion to the washing stream. With this approach, we demonstrate on-chip leukocyte staining with Rhodamine 6G and washing. The results suggest that other conventional biological and analytical processes could be replaced by the proposed device. 相似文献
136.
Emma Lisa Jane Eyre Michael Joseph Duncan Samantha Louise Birch Valerie Cox Matthew Blackett 《Journal of sports sciences》2015,33(3):232-242
Many children fail to meet physical activity (PA) guidelines for health benefits. PA behaviours are complex and depend on numerous interrelated factors. The study aims to develop current understanding of how children from low Socio-economic environments within the UK use their surrounding built environments for PA by using advanced technology. The environment was assessed in 96 school children (7–9 years) using global positioning system (GPS) monitoring (Garmin Forerunner, 305). In a subsample of 46 children, the environment and PA were assessed using an integrated GPS and heart rate monitor. The percentage of time spent indoor, outdoor, in green and non-green environments along with time spent in moderate-to-vigorous PA (MVPA) in indoor and outdoor environments were assessed. A 2-by-2 repeated measures analysis of covariance, controlling for body mass index, BF%, assessed the environmental differences. The findings show that 42% of children from deprived wards of Coventry fail to meet PA guidelines, of which 43% was accumulated during school. Children engaged in more MVPA outdoor than indoor environments (P < 0.01) and a greater amount of time was spent in non-green environments (P < 0.01). Increased time outdoors was negatively associated with BF%. In conclusion, outdoor environments are important for health-enhancing PA and reducing fatness in deprived and ethnic children. 相似文献
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Hyunjin Seo Joseph Erba Darcey Altschwager Mugur Geana 《Journal of Applied Communication Research》2019,47(2):130-152
Based on our community engagement project involving 47 older, low-income African-American adults from a senior community center, this study analyzes how an underserved population acquires knowledge and skills related to digital technologies. We discuss the conceptualization, implementation, and evaluation of a weekly, four-month long computer class for members of the senior community center. Our mixed-method research shows the importance of taking into account both the multidimensional nature of adult learning and the social and cultural contexts in which learning occurs when working with underserved adult populations. Findings from our formative and evaluative research offer insights into changes in the computer class participants’ attitudes toward and perspectives on key digital literacy issues including security and privacy online and online information verification. Scholarly and policy implications are discussed in the context of digital competency and adult learning for marginalized populations. 相似文献
139.
This paper presents a method of general geometrical definitions of screw machine rotors and their manufacturing tools. It
describes the details of lobe shape specification, and focuses on a new lobe profile, which yields a larger cross-sectional
area and shorter sealing lines resulting in higher delivery rates for the same tip speed. A well proven mathematical model
was used to determine the optimum profile, compressor housing size, and compressor ports to achieve the superior compressors. 相似文献
140.
This paper provides insights into teacher and school-based administrators’ responses to policy demands for improved outcomes on high-stakes, standardised literacy and numeracy tests in Australia. Specifically, the research reveals the effects of the National Assessment Program – Literacy and Numeracy (NAPLAN), and associated policies, in the state of Queensland. Drawing suggestively across Michel Foucault’s notions of disciplinary power and subjectivity, and Pierre Bourdieu’s concept of social fields, the research utilises interviews with teachers and school-based administrators to reveal how high-stakes, standardised testing practices served to discursively constitute performative teacher subjectivities around issues of funding, teacher and school reputation and target-setting within what is described as the ‘field of schooling practices’. The paper argues that the contestation evident within this field is also reflective and constitutive of more educative schooling discourses and practices, even as performative logics dominate. 相似文献