Does modality matter? A latent profile and transition analysis of sedentary behaviours among school-aged youth: The UP&DOWN study

ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.     

Quality flaw prediction in Spanish Wikipedia: A case of study with verifiability flaws

In this work, we present the first quality flaw prediction study for articles containing the two most frequent verifiability flaws in Spanish Wikipedia: articles which do not cite any references or sources at all (denominated Unreferenced) and articles that need additional citations for verification (so-called Refimprove). Based on the underlying characteristics of each flaw, different state-of-the-art approaches were evaluated. For articles not citing any references, a well-established rule-based approach was evaluated and interesting findings show that some of them suffer from Refimprove flaw instead. Likewise, for articles that need additional citations for verification, the well-known PU learning and one-class classification approaches were evaluated. Besides, new methods were compared and a new feature was also proposed to model this latter flaw. The results showed that new methods such as under-bagged decision trees with sum or majority voting rules, biased-SVM, and centroid-based balanced SVM, perform best in comparison with the ones previously published.     

不同年龄性别学生健身运动参与动机的探讨

健身运动是促进人类健康的有效途径。通过采用文献资料、问卷调查等方法,以青少年学生为研究对象,调查学生对健身运动的认知、爱好以及参与程度,分析社会因素和心理中介与学生健身运动参与动机之间的关系,对青少年学生健身运动参与动机进行深一层次的探讨,旨在为学校体育教学提供理论参考依据。     

三角形重心性质拾趣——兼谈类比方法在初等数学研究中的运用

运用类比推理的方法,将经过三角形重心的直线的性质推广到三维空间,导出经过三角形重心的平面的若干性质.     

运动员心脏功能典型指标的选择与评价

本研究运用相关检验和聚类分析法等对三十多个心脏形态、功能指标进行了筛选分析，选择出适合评定运动员心脏功能的典型指标，并对所选指标的应用进行了评价。     

普通逻辑基本规律教学摭谈

在同一律教学中 ,要注意讲清什么是“同一思维过程”、什么是“A是A”以及“合理违反同一律”的特殊情况。在不矛盾律教学中 ,要注意讲清“看似矛盾 ,实质上并不矛盾”的概念或判断 ,注意分析具有隐蔽性的逻辑矛盾。在排中律教学中 ,对人们的某些思维或表述 ,要结合语言环境加以分析 ,不能生搬硬套     

试谈在大学体育课程中发挥学生的主体性作用

在高校体育教学中应发挥学生的主体性作用 :学生自主选择课程内容、自主选择任课教师、自主选择上课时间 ;上课突出提高学生参与的积极性 ,最大限度地发挥学生的创造性。加强对学生学习方法和练习方法的指导 ,提高学生自学、自练的能力 ;考核要通过学生自评、互评和教师评定 ,实现三转变 :从终结评价向终结与过程评价结合转变 ;从内容单一评价向多元评价转变 ;从教师评价向师生评价转变 ;同时要发挥教师的主导作用     

复连域上的势函数及其在曲线积分计算中的应用

本文在复连域上引进势函数的概念,并给出其计算方法,以此来解决一些复杂的曲线积分计算问题。