The effect of 14 weeks of vitamin D3 supplementation on antimicrobial peptides and proteins in athletes     

Cheng-Shiun He  William D. Fraser  Jonathan Tang  Kirsty Brown  Stephen Renwick  Jay Rudland-Thomas 《Journal of sports sciences》2016,34(1):67-74

Heavy training is associated with increased respiratory infection risk and antimicrobial proteins are important in defence against oral and respiratory tract infections. We examined the effect of 14 weeks of vitamin D₃ supplementation (5000 IU/day) on the resting plasma cathelicidin concentration and the salivary secretion rates of secretory immunoglobulin A (SIgA), cathelicidin, lactoferrin and lysozyme in athletes during a winter training period. Blood and saliva were obtained at the start of the study from 39 healthy men who were randomly allocated to vitamin D₃ supplement or placebo. Blood samples were also collected at the end of the study; saliva samples were collected after 7 and 14 weeks. Plasma total 25(OH)D concentration increased by 130% in the vitamin D₃ group and decreased by 43% in the placebo group (both P = 0.001). The percentage change of plasma cathelicidin concentration in the vitamin D₃ group was higher than in the placebo group (P = 0.025). Only in the vitamin D₃ group, the saliva SIgA and cathelicidin secretion rates increased over time (both P = 0.03). A daily 5000 IU vitamin D₃ supplement has a beneficial effect in up-regulating the expression of SIgA and cathelicidin in athletes during a winter training period, which could improve resistance to respiratory infections.  相似文献   

The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol     

Jonathan P. Norris  Jamie Highton  Stephen F. Hughes  Craig Twist 《Journal of sports sciences》2016,34(19):1859-1866

The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HR_peak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance.  相似文献   

Reassessing the People's Choice: Revisiting a Classic and Excavating Lessons for Research About Media and Voting     

Stephen Lacy  Michael Stamm 《Mass Communication and Society》2016,19(2):105-126

This article reassesses The People's Choice by Paul Lazarsfeld, Bernard Berelson, and Hazel Gaudet, one of the foundations of communication and voting behavior research. As with most classics, which are often cited but seldom read, we believe this book has much to teach contemporary social scientists. We return to the original context of the research and use voting data from the period with three broad goals: (a) to find ideas and lessons from this work that generally have been overlooked, (b) to suggest new ways of applying these ideas, and (c) to encourage scholars to engage more with this seminal work to understand ideas that are often overlooked when a complex piece of research is reduced to a brief discussion or passing citation.  相似文献   

Building a Foundation for the Use of Historical Narratives     

Don Metz  Stephen Klassen  Barbara McMillan  Michael Clough  Joanne Olson 《Science & Education》2007,16(3-5):313-334

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Designing programs for community groups : S.V. Martorana and W.E. Piland. San Francisco, CA: Jossey-Bass 1984. $8.95 (paper)     

Stephen D. Millman 《Economics of Education Review》1985,4(4):357-358

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Teaching common errors in applying a procedure     

Marcone  Stephen  Reigeluth  Charles M. 《Educational technology research and development : ETR & D》1988,36(1):23-32

This study investigated whether or not the teaching of matched examples and nonexamples in the form of common errors would improve student performance in applying a procedure to previously unencountered instances, and whether the common errors would be most beneficial in generality form, in example form, or in both forms. Participants were 141 first-year music students, who were randomly assigned to four groups and given the task to learn a procedure that was presented in a self-contained booklet. A pretest-posttest experimental design was used, with a prerequisite test given as a screening device. The two independent variables were the absence and presence of the common errors in the generality form and in the example form (2 x 2 factorial design). Results indicated that the teaching of common errors in the generality form significantly improved learning a procedure at the application level of behavior.  相似文献   

Postmodernist prose and George Orwell     

Stephen K. Roney 《Academic Questions》2002,15(2):13-23

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On the nature of the primacy effect in memory processing: A reply to Gaffan     

Anthony A. Wright  Hector C. Santiago  Stephen F. Sands 《Learning & behavior》1983,11(1):148-150

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La Parte Chusca of a Pedagogical Here and Now: Oaxacan Teachers’ Heteroglossic Joking About State Repression and Educational Reform     

Stephen T. Sadlier 《Journal of Latinos & Education》2016,15(4):320-332

Faced with repression and reform, humor has become tactical for public school teachers in Oaxaca, Mexico, engaged in a decades-old movement that after 2006 involved intensified street- and school-based pedagogies. This piece explores how humor adds to a political project via mocking names, images, and dictates of elite leaders to bring a here and now to what is taken as inaccessible in the teachers’ political lives. Humor forms part of an (e)sc(h)atology in which critical practices are part eschatological, a call for definite transformation, and part scatological, embodied vulgarity. La parte chusca (the funny part), its (e)sc(h)atological contribution, angles toward critical literacies in Oaxaca and beyond.  相似文献   

Getting a Purchase on "The School of Tomorrow" and its Constituent Commodities: Histories and Historiographies of Technologies     

Stephen Petrina 《History of education quarterly》2002,42(1):75-111

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