Constraints on dynamic stability during forward,backward and lateral locomotion in skilled football players     

Sina Mehdizadeh  Keith Davids 《European Journal of Sport Science》2016,16(2):190-198

The aim of this study was to investigate effects of speed and plane of motion on stability during locomotion in skilled football players. Ten male national-level football players participated in this study to run forward, backward and in lateral directions on a treadmill at 80%, 100% and 120% of their preferred running speeds. The coordinate data of passive reflective markers attached to body segments were recorded using motion capture systems. Time series data obtained from the ankle marker were used for further analyses. The largest finite-time Lyapunov exponent and maximum Floquet multiplier were adopted to quantify local and orbital dynamic stabilities, respectively. Results showed that speed did not significantly change local and orbital dynamic stabilities in any of running patterns. However, both local and orbital dynamic stability were significantly higher in the secondary plane of progression. Data revealed that in running, unlike walking, stability in the direction perpendicular to the direction of running is significantly higher, implying that less active control is required in the secondary plane of progression. The results of this study could be useful in sports training and rehabilitation programmes where development of fundamental exercise programmes that challenge both speed and the ability to maintain stability might produce a tangible enhancement of athletic skill level.  相似文献   

Research for policy: impact,uptake, or silence?     

Keith Morrison  Greetje van der Werf 《Educational Research and Evaluation》2016,22(7-8):351-353

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Getting published is not a walk in the woods     

Keith Morrison 《Educational Research and Evaluation》2017,23(7-8):269-271

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Framing Wind Energy: Strategic Communication Influences on Journalistic Coverage     

Keith Joseph Zukas 《Mass Communication and Society》2017,20(3):427-449

The dominance of political communication over an issue like wind energy has the power to overwhelm attempts to frame wind farming as a scientific or environmental issue in the mediated public sphere. Using regulation as the primary newsmaker, politicians instead of scientists or environmental organizations become journalists’ sources in framing the issue. Wind energy is a special issue that is framed in unique ways due to environmental, political, and industry ties. Contest framing ensues between institutional stakeholders to win favorable media coverage. Through a sociological lens, this analysis examines how contemporary political communications continue to influence the media through professional routines and relationships even in a scientifically grounded industry during a surge of public environmentalism. Comparisons of political, energy industry, and environmental advocacy communications show that political and energy industry frames dominate newspaper coverage of energy issues even when environmental and scientific issues are inherent to the story.  相似文献   

An Analysis of Degree Results in Geography by Gender     

Keith Chapman 《Assessment & Evaluation in Higher Education》1996,21(4):293-311

Chi‐square analysis is used to test for differences in the degree results of male and female geography graduates from 42 UK universities between 1973 and 1993. The combined results of these universities (i.e. departments at subject‐specific level) show a persistent and striking overrepresentation of males with thirds and pass degrees together with a less obvious, but statistically significant, overrepresentation of males achieving firsts. Corresponding analyses for individual departments emphasise the need for caution in deriving generalisations from aggregate data. A significant difference (at the 99% level) in the cumulative annual degree results of males and females is found in 10 of the 42 departments. The sources of these differences vary and it is suggested that a distinction is drawn between general factors responsible for the pervasive overrepresentation of males in the third/pass categories and department‐specific factors responsible for gender differences in other degree classes, especially firsts.  相似文献   

Theoretical perspectives on learning in an informal setting     

David Anderson  Keith B. Lucas  Ian S. Ginns 《科学教学研究杂志》2003,40(2):177-199

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Components of phonological awareness     

Torleiv Høien  Ingvar Lundberg  Keith E. Stanovich  Inger-Kristin Bjaalid 《Reading and writing》1995,7(2):171-188

The factorial structure underlying different types of tasks within the domain of phonological awareness was examined in two studies. Large sample sizes allowed for sensitive differentiation of constructs. In the first study, 128 preschool children without any experience of formal reading instruction were tested with a battery of tasks intended to tap various aspects of phonological awareness: rhyme recognition, syllable counting, initial-phoneme matching, initial-phoneme deletion, phoneme blending, and phoneme counting. Three basic components were extracted in a principal component analysis: a phoneme factor, a syllable factor and a rhyme factor. Cross-tabulations indicated considerable dissociation between performance on phoneme, syllable, and rhyme tasks. The structural relationships were replicated on a much larger sample (n=1509) in the second study. Subjects in this study were one year older and were attending grade 1 thus providing an opportunity to test their reading achievement. Multiple regression analyses demonstrated that the phonemic factor was by far the most potent predictor. However, the rhyming factor made an independent (although small) contribution to explaining the reading variance. Among the phonemic tasks, phoneme identification proved to be the most powerful predictor.  相似文献   

Minor Parenting Stresses with Young Children   总被引：15，自引：0，他引：15  

Keith A. Crnic  Mark T. Greenberg 《Child development》1990,61(5):1628-1637

The importance of major life stress and minor daily hassles associated with parenting was studied in 74 mothers and their 5-year-old children. Of interest were the relative and absolute contributions of the stress factors to indices of parental, child, and family functioning. Mothers completed questionnaires regarding stressors, aspects of parenting and individual psychological status, social support, family functioning, and child behavioral status. Mother-child pairs were also observed in interactions in a laboratory setting. Analyses indicated that life stress and parenting daily hassles significantly predicted aspects of child, parent, and family status. Hassles, however, proved to be a more powerful stress construct. Further analyses indicated that mothers' social support moderated the influence of hassles on indices of maternal behavior. The results are discussed in relation to the potential for minor parenting stresses to influence microsocial processes within parent-child relationships and contribute to dysfunction in children and families.  相似文献   

Portfolio versus syllabus methods in experiential education     

D. Keith Lupton 《Innovative Higher Education》1979,4(2):114-126

The portfolio method of assessing past experience for the award of academic credit is being nationally promoted by the Council for the Advancement of Experiential Learning (CAEL). The portfolio method has evolved since 1974 and is used in a number of colleges and universities. The project-syllabus method was developed by the author in 1969 to support experiential credit for students in sponsored experiences. Beginning about 1973, the project-syllabus method was also used to support credit for past experiences in some areas. These two methods are contrasted, comparisons made to traditional classroom methods, and strengths and weaknesses analyzed.D. Keith Lupton, the Guest Editor for this issue, is the Director of the Off-Campus Term Program, University of South Florida.  相似文献   

The Contribution of Educational Psychology to Intervention Research and Practice     

William E. Tunmer  James W. Chapman  Keith T. Greaney  Jane E. Prochnow 《International Journal of Disability, Development & Education》2002,49(1):11-29

Advances in psychological theory have made significant contributions to the considerable progress that has been achieved in intervention research and practice, especially in the past two decades. This article presents a discussion of the major conceptual and methodological issues that have arisen in intervention research, with a focus on interventions for children with learning problems, particularly reading problems. Examples from our own research are presented to illustrate how conceptual and methodological factors in intervention research can be taken into consideration in the design of intervention studies.  相似文献