Unsteady flow phenomena in human undulatory swimming: a numerical approach     

Steffen Pacholak  Stefan Hochstein  Alexander Rudert  Christoph Brücker 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):176-194

The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition.  相似文献   

Writing learning journals: Instructional support to overcome learning-strategy deficits     

Sandra Hübner  Matthias Nückles  Alexander Renkl 《Learning and Instruction》2010,20(1):18-29

Although writing learning journals is a powerful learning tool, instructional support is needed to overcome deficits in the use of self-regulated learning strategies. In a 2 × 2 experimental design with high-school students (N = 70), we analysed the effects of two modes of instruction (namely, informed prompting and learning-journal example) along with prompts. Informed prompting that provided background information on the prompted strategies enhanced learning in the training and transfer session. A learning-journal example that modelled the application of the strategies primarily fostered the strategy used in the training session and learning in the transfer session. Theoretically, the results provide support for the self-regulation view of writing-to-learn.  相似文献   

Paul the “Slave of Jesus Christ”     

J. Alexander Findlay M.A. 《British Journal of Religious Education》1935,2(1):13-23

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Israel and the Teaching of Jewish Identity     

Alexander M. Dushkin 《Journal of Jewish Education》2013,79(2-3):21-26

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Soviet Preschool Education: Program of Instruction,Volume I,edited by Henry Chauncey. New York: Holt,Rinehart & Winston,Inc., 1969. 182 pp. $2.95     

Alexander M. Chabe 《The Educational forum》2013,77(4)

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EDITORIALS     

Alexander M. Dushkin 《Journal of Jewish Education》2013,79(3):130-145

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Reviewer acknowledgements 2014     

Alison Campbell 《Teachers and Teaching》2013,19(4):490-491

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Reviews     

Alison Fuller  Rosalind Pritchard  Paul Trowler 《Higher Education Quarterly》2003,57(2):204-210

Books reviewed in this article:
L. Archer, M. Hutchings and A. Ross, with C. Leathwood, R. Gilchrist and D. Phillips, Higher Education and Social Class: Issues of Exclusion and Inclusion
John Brennan and Tarla Shah, Managing Quality in Higher Education: An International Perspective on Institutional Assessment and Change
R. Taylor, J. Barr and T. Steele, For a Radical Higher Education: After Postmodernism  相似文献   

Reading and talking with 7- to 9-year-olds     

L. Alison Burgess 《Journal of Research in Reading》1985,8(1):59-59

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Pushout: The Criminalization of Black Girls in Schools by Monique W. Morris.     

Alexander Pope IV 《The Educational forum》2017,81(2):231-232

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