The core musculature in male prepubescent tennis players and untrained counterparts: a volumetric MRI study

The effects of exercise on the core musculature have not been investigated in prepubescents. The main purpose of the present study was to determine the volume and degree of asymmetry of rectus abdominis, obliques and transversus abdominis, quadratus lumborum, iliopsoas, gluteus and paravertebralis muscles in prepubescent tennis players and in untrained boys. The muscle volume was determined using magnetic resonance imaging (MRI) in 7 male prepubescent tennis players and 10 untrained controls (mean age 11.0 ± 0.8 years, Tanner 1–2). After accounting for height and body weight as covariates, the tennis players had 14–34% greater volume than the controls in all the muscles analysed (P < 0.05) except in paravertebralis, dominant quadratus lumborum and non-dominant gluteus, which had similar volumes in both groups (P = NS). Compared to controls, the tennis players displayed a greater degree of asymmetry in quadratus lumborum and rectus abdominis (3% vs. 15%, P < 0.01 and 8% vs. 17%, P = 0.06, respectively). The level of asymmetry of obliques and transversus abdominis, iliopsoas, gluteus and paravertebralis muscles was similar in both groups (P = NS). In conclusion, tennis playing at prepubertal ages induces a selective hypertrophy of the core musculature and exaggerates the degree of asymmetry of quadratus lumborum and rectus abdominis compared to untrained boys.     

Combinations of Epoch Durations and Cut-Points to Estimate Sedentary Time and Physical Activity Among Adolescents

The purpose of the current study was to investigate how combinations of different epoch durations and cut-points affect the estimations of sedentary time and physical activity in adolescents. Accelerometer data from 101 adolescents were derived and 30 combinations were used to estimate sedentary time, light, moderate, vigorous, and combined moderate-to-vigorous physical activity. Data were analyzed with repeated measurement analyses of variance. Large differences of sedentary time and times of different physical activity intensities were observed between 1 s and longer epoch durations using virtually all cut-points. Generally, sedentary time, moderate physical activity, vigorous physical activity, and combined moderate-to-vigorous physical activity progressively decreased, whereas light physical activity increased with longer epoch durations. The extreme differences between cut-points were large and increased with longer epoch durations for sedentary time and for all physical activity intensities except for vigorous physical activity per epoch duration. Caution is required when cross-comparing studies using different epoch durations and cut-points. To accurately register adolescents’ spontaneous intermittent physical activity behavior, short epoch durations are recommended.     

Being hurt and hurting others: children's narrative accounts and moral judgments of their own interpersonal conflicts

Children's narrative accounts and moral evaluations of their own interpersonal conflicts with peers were examined. Girls and boys (N = 112) in preschool (M= 4.8 years), first grade (M = 6.9 years), fifth grade (M = 10.9 years), and tenth grade (M = 16.2 years) provided one narrative of a time when they had been hurt by a peer ("victim"), and one of a time when they had hurt a peer ("perpetrator"). Victim and perpetrator narratives were equally long and detailed and depicted similar types of harmful behaviors, but differed significantly in terms of various measures of content and coherence. Narratives given from the victim's perspective featured a self-referential focus and a fairly coherent structure. When the same children gave accounts of situations in which they had been the perpetrators, their construals were less coherent and included multiple shifts between references to their own experience and the experience of the other. Children's moral judgments also varied by perspective, with the majority of victims making negative judgments and nearly half the perpetrators making positive or mixed judgments. These differences in moral judgments were related to the distinct ways in which victims and perpetrators construed conflict situations. Age differences were also found in both narrative construals and moral evaluations, but regardless of their age children construed conflict situations differently from the victim's and the perpetrator's perspectives. By integrating, within the study of moral development, children's interpretations of the social interactions that are at the basis of moral thinking, this approach brings us a step closer to conceptualizing the study of children's moral behavior.     

Observational studies about novices interacting in a Prolog environment based on tools

This paper examines the general issues related to the interaction of novices in a Prolog environment based on tools to support both the operational and the declarative aspects of the language. The tools are based on graphical representations for the Prolog program and for Prolog execution of programs. This research aims to investigate how students come to understand and integrate these different views of Prolog and how the tools affect their understanding of the language.Observations conducted during this study show that the novices had an initial conceptual model of the virtual machine. Such models guided their interpretation of the Prolog program and of the behavior of the machine. Their misunderstandings may be interpreted as having resulted from their current models. These models evolved during their interaction within the environment. The type of feedback created by the tools provided changes in the students perspective related to the knowledge being represented (program) and the interlocutor in the process (virtual machine), which led them to the construction of the conceptual model of the language.     

Potential conflicts between ownership rights and environmental protection: Swedish undergraduate students’ views

Abstract

This study examines the perspectives of Swedish undergraduate students regarding potential conflicts between ownership rights and environmental protection. Conceptions of ‘ownership’ are relevant in relation to the environment and environmental protection as they can highlight a more transboundary relationship between the individual/society and nature. Students studying economics, law and political science were chosen because of their potential future transformative roles as decision makers and policy makers. Content analysis was employed to examine the written responses of 747 students from seven different universities to the open-ended survey question: Can ownership rights and environmental protection come into conflict? Students’ responses were measured twice: at the very beginning of the first semester and then again at the end of the semester. The results show that students expressed a dominant view of ownership in terms of individual ownership, and associations to collective ownership were largely absent. In regards to the potential conflict between ownership rights and environmental protection, most students perceived such a conflict, and it was more common for the environment to be conceptualised as the losing party rather than the landowner. More research is needed regarding how teaching and instruction can deal with the potential conflicts between ownership (private/corporate/governmental) and environmental protection.     

Moral development in a violent society: Colombian children's judgments in the context of survival and revenge

Ninety-six Colombian children (mean age = 7.7 years) and adolescents (mean age = 14.6 years) made judgments about stealing and physical harm in the abstract and in the context of survival and revenge. All participants judged it wrong to steal or hurt others because of considerations with justice and welfare, and most also judged it wrong to engage in such actions even when they can aid in survival. Their judgments in the context of revenge were more mixed, with a sizable proportion endorsing stealing and hurting in that condition. Furthermore, the majority expected that people would steal and hurt others in most situations. Significant age differences were also found. The consequences of political violence for moral development are discussed.     

Cultural‐competence considerations for contemporary school‐based threat assessment

Threat‐assessment procedures are advanced for their utility in reducing racial disparities in punitive and exclusionary school discipline outcomes. Generally unexamined, however, is bias in who gets referred for school‐based threat assessment and under what circumstances. Cultural‐competence considerations hold promise for addressing sources of bias in the evaluation of threats made in the school setting. Using a quantitative approach, this systematic literature review examines the degree to which contemporary cultural‐competence considerations are embedded in 24 school‐based threat‐assessment articles published between 2007 and 2017. Results indicate generally poor coverage of considerations for cultural competence both within and across threat‐assessment articles. An analysis of change in cultural‐competence considerations by year of publication suggests that more recently published threat‐assessment literature has generally not integrated concurrent advancements in concepts of cultural competence. Preliminary guidance for incorporating contemporary cultural‐competence considerations into school‐based threat‐assessment procedures are provided.