Kinematics of the field hockey penalty corner push-in

The aims of the study were to determine those variables that significantly affect push-in execution and thereby formulate coaching recommendations specific to the push-in. Two 50 Hz video cameras recorded transverse and longitudinal views of push-in trials performed by eight experienced and nine inexperienced male push-in performers. Video footage was digitized for data analysis of ball speed, stance width, drag distance, drag time, drag speed, centre of massy displacement and segment and stick displacements and velocities. Experienced push-in performers demonstrated a significantly greater (p < 0.05) stance width, a significantly greater distance between the ball and the front foot at the start of the push-in and a significantly faster ball speed than inexperienced performers. In addition, the experienced performers showed a significant positive correlation between ball speed and playing experience and tended to adopt a combination of simultaneous and sequential segment rotation to achieve accuracy and fast ball speed. The study yielded the following coaching recommendations for enhanced push-in performance: maximize drag distance by maximizing front foot-ball distance at the start of the push-in; use a combination of simultaneous and sequential segment rotations to optimise both accuracy and ball speed and maximize drag speed.     

我所犯的错误之本質与其原因

對於我的『敎育學原理』一書的討論已經繼續了三天。討論是在對我作原則性批評的環境中,首先是在自我批評和分析我們敎育科學原理的環境下進行的。我認爲對於我的『敎育學原理』一書的批評是正確的、是布爾什維克的。同志們的批評對我有很大的幫助。我在我的作品出版以前和出版以後會經將它讀過好幾遍。我自己也見到了和知道了我作品中一系列的錯誤與遺漏,但是根據我在這個會上所聽到的,我應該爽直並誠懇地說一說甚至自己没有懷疑過的許多東西.這是顯而易見的。所有髮言的同志們不單是個别地、各自分別地,並且在有敎師們參加的教育學院和師範學院的敎育系中都仔細地分析了我的著作。     

北京、上海、广州、深圳体育产业比较研究

体育产业已成为城市经济社会发展的重要推动力;本文主要采用文献资料研究法、调查法、数理统计法、比较分析法等研究方法,对北京、上海、广州和深圳四大国内前沿城市的体育产业及其影响因素进行了剖析。结果表明,四个城市的体育产业与城市经济社会发展水平密切相关,在政府的支持与投入下,通过举办大型体育赛事,发展健身娱乐业,培育体育市场等,体育产业发展各有特色,对其它城市具有借鉴作用。     

Factors associated with concussion-symptom knowledge and attitudes toward concussion care seeking in a national survey of parents of middle-school children in the US

Background:Developing appropriate concussion prevention and management paradigms in middle school(MS)settings requires understanding parents’general levels of concussion-related knowledge and attitudes.This study examined factors associated with concussion-symptom knowledge and care-seeking attitudes among parents of MS children(aged 10-15 years).Methods:A panel of 1224 randomly selected U.S.residents,aged ≥18 years and identifying as parents of MS children,completed an online questionnaire capturing parental and child characteristics.The parents’concussion-symptom knowledge was measured using 25 questions,with possible answers being“yes”,“maybe”,and“no”.Correct answers earned 2 points,“maybe”answers earned 1 point,and incorrect answers earned 0 point(range:0-50;higher scores=better knowledge).Concussion care-seeking attitudes were also collected using five 7-point scale items(range:5-35;higher scores=more positive attitudes).Multivariable ordinal logistic regression models identified predictors of higher scores.Models met proportional odds assumptions.Adjusted odds ratios(aORs)with 95%confidence intervals(95%CIs)(excluding 1.00)were deemed statistically significant.Results:Median scores were 39(interquartile range:32-44)for symptom knowledge and 32(interquartile range:28-35)for care-seeking attitude.In multivariable models,odds of better symptom knowledge were higher in women vs.men(aOR=2.28;95%CI:1.71-3.05),white/non-Hispanics vs.other racial or ethnic groups(aOR=1.88;95%CI:1.42-2.49),higher parental age(10-year-increase aOR=1.47;95%CI:1.26-1.71),and greater competitiveness(10%-scale-increase aOR=1.24;95%CI:1.13-1.36).Odds of more positive care-seeking attitudes were higher in white/non-Hispanics vs.other racial or ethnic groups(aOR=1.45;95%CI:1.06-1.99)and in older parental age(10-year-increase aOR=1.24;95%CI:1.05-1.47).Conclusion:Characteristics of middle school children’s parents(e.g.,sex,race or ethnicity,age)are associated with their concussion-symptom knowledge and care-seeking attitudes.Parents’variations in concussion knowledge and attitudes warrant tailored concussion education and prevention.     

语义计算的本体和约束

语义计算的目的是在用户和计算机共享的涵义和词汇的基础上设计和操作信息系统.它旨在缩小语义差距,使用户和信息系统能更好地协同工作,从而在语义学意义上使我们的生活更加丰富.文章将探讨以本体和约束为主要技术来实现用户和信息系统之间的涵义共享.     

Decrease in Ammonia Excretion by Boleophthalmus Boddaerti(Mudskipper) Exposed to Cyanide

ThetoleranceofthemudskipperBoleophthalmusboddaertitocyanideishigherthanthoseofotherfishes[1].Suchahightolerancetocyanidedoesnotinvoveareductionofmetabolicrateoranenhancedanaerobicmetabolism,oracyanide-insensitiverespiratorypathway.Instead,itisaresultofthepresenceofasurplusofcytochromeoxidaseandinduciblecyanide-detoxifyingmechanisms,tumingcyanideinthiocyanate,inthismudskipper[1].ThoughCN-isdetoxifiedtoSCN-,realizingbiomembranesaremorepermeabletoHCNthanCN-,wedecidedtoinvestigateiftheprotondi…     

关于加强节目主持人和播音员队伍管理的建议

一、对节目主持人和播音员队伍现状的分析1991年6月江苏县以上电台、电视台的播音员共约500人,节目主持人很少。这三年来,一部分播音员转为专职节目主持人;一部分播音员既播音又主持节目;还有一部分仍然只搞播音工作。与此同时,节目主持人则急剧增多。据不完全统计,目前全省在编的