简介:在本期的“课例大家评”中,我们刊登了同一课题下的6篇课例供大家点评.2001年第4期,我刊登出了“直线方程的一般形式(第一课时)”课例的征稿启事.截止4月30日,我们收到课例来稿百余篇.这6篇课例就是从这些应征稿件中遴选出来的.为了便于大家点评,我们将6篇课例按学生学习状况的优、中、差分为三组,每组有2篇课例.在撰写点评稿时,您可以对6篇课例进行总评,也可以就学生学习状况相当的两篇课例进行评析,还可以对某一课例做单独的评议.总之,点评的内容应相对集中,以便于编者对稿件进行选择和组构.文稿字数以1000字左右为宜,截稿日期为9月10日.投稿时请在信封左下方注明“课例大家评”字样.欢迎广大数学教师和教研工作者积极参与本次“课例大家评”活动,我们将以较大篇幅集中发表观点新颖、论述深刻、对教学具有较强启发性的优秀来稿.在此,我们还特别对提供“直线方程的一般形式”课例的所有老师表示衷心的感谢.
简介:Background:Overweightandobesityhasbecomeaseriouspublichealthprobleminmanypartsoftheworld.Studiessuggestthatmakingsmallchangesindailyactivitylevelssuchas"breaking-up"sedentarytime(i.e.,standing)mayhelpmitigatethehealthrisksofsedentarybehavior.Theaimofthepresentstudywastoexaminetimespentinstanding(determinedbycountthreshold),lying,andsittingpostures(determinedbyinclinometerfunction)viatheActiGraphGT3Xamongsedentaryadultswithdifferingweightstatusbasedonbodymassindex(BMI)categories.Methods:Participantsincluded22sedentaryadults(14men,8women;meanage26.5±4.1years).Allsubjectscompletedtheself-reportInternationalPhysicalActivityQuestionnairetodeterminetimespentsittingovertheprevious7days.Participantswereincludediftheyspentsevenormorehourssittingperday.PosturesweredeterminedwiththeActiGraphGT3Xinclinometerfunction.Participantswereinstructedtoweartheaccelerometerfor7consecutivedays(24haday).BMIwascategorizedas:18.5to<25kg/m2asnormal,25to<30kg/m2asoverweight,and≥30kg/m2asobese.Results:Participantsinthenormalweight(n=10)andoverweight(n=6)groupsspentsignificantlymoretimestanding(afteradjustmentformoderate-to-vigorousintensityphysicalactivityandwear-time)(6.7hand7.3hrespectively)andlesstimesitting(7.1hand6.9hrespectively)thanthoseinobese(n=6)categories(5.5hand8.0hrespectively)afteradjustmentforwear-time(p<0.001).Therewerenosignificantdifferencesinstandingandsittingtimebetweennormalweightandoverweightgroups(p=0.051andp=0.670respectively).Differenceswerenotsignificantamonggroupsforlyingtime(p=0.55).Conclusion:Thisstudydescribedposturalallocationsstanding,lying,andsittingamongnormalweight,overweight,andobesesedentaryadults.Theresultsprovideadditionalevidencefortheuseofincreasingstandingtimeinobesitypreventionstrategies.