Having students create short video clips to help transition from naïve conceptions about mechanics to true Newtonian physics

Most students enter their first university physics course with a system of beliefs and intuitions which are often inconsistent with the Newtonian frame of reference. This article presents an experiment of collaborative learning aiming at helping first-year students in an engineering programme to transition from their naïve intuition about dynamics to the Newtonian way of thinking. In a first activity, students were asked to critically analyse the contents of two video clips from the point of view of Newtonian mechanics. In a second activity, students had to design and realise their own video clip to illustrate a given aspect of Newtonian mechanics. The preparation of the scenario for the second activity required looking up and assimilating scientific knowledge. The efficiency of the activity was assessed on an enhanced version of the statistical analysis method proposed by Hestenes and Halloun, which relies on a pre-test and a post-test to measure individual learning.     

The Decline of Women Leaders (Coaches and Athletic Directors) in Girls' Interscholastic Sport Programs in Virginia from 1972 to 1987

Abstract

The purpose of this study was to determine if static and baltislic stretching would, induce significant amounts of delayed onset muscle soreness (DOMS) and increases in creatine kinase (CK). Twenty males were randomly assigned to a static (STATIC) or ballistic stretching (BALLISTIC) group. All performed three sets of 17 stretches during a 90-min period, the only group difference being that STATIC remained, stationary during each 60-s stretch while BALLISTIC performed, boundng movements. Subjective ratings of DOMS (scale: 1–10) and serum CK levels were assessed before and every 24 hours post stretching, for 5 days. A repeated measures ANOVA revealed a significant main effect due to time (p < .05), with peak soreness occurring at 24 hours after (M = 2.8 ? 1.6). Surprisingly, a group effect (p < .05) demonstrated. that DOMS was significantly greater for STATIC than for BALLISTIC. At 24 hours there was a 62% (p < .05) increase in CK for combined groups. These findings indicate that similar bouts of static and ballistic stretching induce significant increases in DOMS and CK in subjects unaccustomed to such exercise. Furthermore, static stretching induced significantly more DOMS than did ballistic.     

Avoiding and Correcting Bias in Score-Based Latent Variable Regression With Discrete Manifest Items

This article considers models involving a single structural equation with latent explanatory and/or latent dependent variables where discrete items are used to measure the latent variables. Our primary focus is the use of scores as proxies for the latent variables and carrying out ordinary least squares (OLS) regression on such scores to estimate parameters in the structural equation. We are concerned with the bias in these OLS estimates; we present two approaches to deal with this bias. Extending the work of Skrondal and Laake (2001) Skrondal, A. and Laake, P. 2001. Regression among factor scores. Psychometrika, 66: 563–576. [Crossref], [Web of Science ®] , [Google Scholar] on continuous items, we derive sufficient conditions under which the use of scores based on item response theory leads to unbiased OLS estimates at the population level; we deem this approach “bias avoiding.” We also consider Croon's (2002) Croon, M. 2002. “Using predicted latent scores in general latent structure models”. In Latent variable and latent structure models, Edited by: Marcoulides, G. A. and Moustaki, I. 195–223. Mahwah, NJ: Lawrence Erlbaum Associates, Inc.  [Google Scholar] bias correction methodology for continuous items and explore its efficacy on discrete items; we deem this approach “bias correcting.” We illustrate the performance of the 2 approaches through numerical examples of large simulated data sets.     

Teachers’ Autonomy in Today's Educational Climate: Current Perceptions From an Acceptable Instrument

This research evaluated the psychometric properties of Friedman's (1999) Teacher Work-Autonomy Scale (TWA) to determine whether it was an acceptable instrument to measure U.S. teacher autonomy in the present educational context. A second purpose was to ascertain the current status of teachers’ perceptions of their autonomy from a sample of U.S. teachers. Four hundred seventy-seven teachers from three public schools in Michigan participated in this study for a response rate of 30%. Factor analysis confirmed the multifaceted nature of teacher autonomy; however, somewhat different factor structures were found for the elementary and secondary teachers in this study, in comparison to that of Friedman. The TWA, without major modifications, appeared to be a valid and reliable instrument for use with a U.S. secondary sample but with limitation with an elementary sample. Elementary and secondary teachers perceived autonomy in the different factors in identical order, but with significant differences between their scores. Differences in school structure and conceptions of autonomy may have contributed to grade-level discrepancies. The findings suggest that administrators may be able to enhance teacher autonomy by releasing some of their power to include teachers in school leadership, specifically in the two areas teachers perceived with lowest autonomy: school finances and professional development.     

Sexual harassment among adolescents of different sexual orientations and gender identities

This article examines (a) variation in rates of sexual harassment across mode (e.g., in-person, online) and type of harassment, (b) the impact of sexual harassment (i.e., distressing vs. non-distressing), and (c) how sexual harassment is similarly and differently experienced across sexual orientation and gender identity groups. Data were collected as part of the Teen Health and Technology online survey of 5,907 13 to 18 year-old Internet users in the United States. Past year sexual harassment was reported by 23–72% of youth, depending upon sexual orientation, with the highest rates reported by lesbian/queer girls (72%), bisexual girls (66%), and gay/queer boys (66%). When examined by gender identity, transgender youth reported the highest rates of sexual harassment – 81%. Overall, the most common modes for sexual harassment were in-person followed by online. Distress in the form of interference with school, family, and/or friends; creating a hostile environment; or being very/extremely upset was reported by about half of the sexually harassed bisexual girls and lesbian/queer girls, 65% of the gender non-conforming/other gender youth, and 63% of the transgender youth. Youth with high social support and self-esteem were less likely to report sexual harassment. Findings point to the great importance of sexual harassment prevention for all adolescents, with particular emphasis on the unique needs and experiences of youth of different sexual orientations and gender identities. Socio-emotional programs that emphasize self-esteem building could be particularly beneficial for reducing the likelihood of victimization and lessen the impact when it occurs.     

Physical activity, nutrition, screen time and sleep associated with body weight and physical condition in young children

The aim of this cross-sectional study was to explore the possible relationship between (un)healthy behaviour and (over)weight and physical condition in families with young children (4–7 years), in a village (30,000 inhabitants) in the eastern part of the Netherlands, close to Germany. It is one of two pilot studies as a precursor of a cross-border project including six Dutch and six German villages, to counteract physical inactivity and possible future metabolic problems. In total, 459 children of five elementary schools and their parents were included. Parents were requested to fill in a questionnaire on the nutritional, physical, sedentary, and sleeping behaviour of their child. Relevant background characteristics were obtained and lifestyle classifications were made. At school, the children's height and weight (body mass index (BMI)) were measured, as well as their physical condition (two tests) and basic motor abilities (four physical exercise tests). The relationship between the standardized BMI z-scores and physical condition test scores, and nutritional, physical, sedentary and sleeping habits was analysed using independent sample t-test, bivariate correlation analysis and multiple regression analysis. Latent class analysis was used to identify clusters of people based on their nutritional, physical and sleep habits. Of the parents, 376 (82?%) were willing to fill out the questionnaire. High birth weight and a high BMI of the mother and/or father correlated with a higher BMI of the child (ρ?=?0.28, p?<?0.001; ρ?=?0.13, p?=?0.016; and ρ?=?0.23, p?<?0.001, respectively). Daily playing outside, eating small cookies (compared with large cookies) and no sleeping problems (no waking up during the night) were related to low BMI levels (no overweight) [ρ?=???0.14, p?=?0.005; ρ?=???0.12, p?=?.020; t(364)?=?1.81, p?=?0.072 (trend), respectively]. Daily playing outside (frequency and duration) and being a member of a sports club were related to positive scores on the physical condition tests [ρ?=?0.20, p?<?0.001; t(365)?=???2.99, p?=?0.003, respectively]. High levels of television (TV) watching and general sleeping problems were related to a less optimal physical condition [ρ?=???0.09, p?=?0.076 (trend); and ρ?=???0.10, p?=?0.059 (trend), respectively]. A latent class analysis revealed three clusters: 46?% of the sample belonged to the ‘healthy group’ concerning nutrition, sedentary lifestyle and TV/personal computer (PC) use; 17?% to the ‘less healthy’ group and 37?% to a group with nutrition and physical activity habits close to the healthy group, but with low conditional probabilities for the sleeping items. Conducting a pilot study before the start of a binational intervention study gives a blueprint for the final questionnaire, and clues for tailored interventions in the schools, as proposed in the approach of ‘Gesunde Kinder in gesunden Kommunen’ (GKGK). The results of a latent class analysis underscore that interventions should exist of a multi-component strategy, focusing on promoting physical activity, healthy nutrition habits and appropriate sleep.