857,669 research outputs found

    The relationship between game rules and team cohesion: an empirical study

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    Multiplayer games (both face-to-face and online) frequently feature teams. This study investigates whether it is possible to use the rules of a game to alter the team cohesion. Game rules from two face-to-face games were analyzed using Social Identity Theory to predict which will lead to more cohesive teams. Significant differences in team cohesion ratings given by the players after the games suggest that the game rules may indeed affect the team cohesion as predicted

    The Case for Dynamic Models of Learners' Ontologies in Physics

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    In a series of well-known papers, Chi and Slotta (Chi, 1992; Chi & Slotta, 1993; Chi, Slotta & de Leeuw, 1994; Slotta, Chi & Joram, 1995; Chi, 2005; Slotta & Chi, 2006) have contended that a reason for students' difficulties in learning physics is that they think about concepts as things rather than as processes, and that there is a significant barrier between these two ontological categories. We contest this view, arguing that expert and novice reasoning often and productively traverses ontological categories. We cite examples from everyday, classroom, and professional contexts to illustrate this. We agree with Chi and Slotta that instruction should attend to learners' ontologies; but we find these ontologies are better understood as dynamic and context-dependent, rather than as static constraints. To promote one ontological description in physics instruction, as suggested by Slotta and Chi, could undermine novices' access to productive cognitive resources they bring to their studies and inhibit their transition to the dynamic ontological flexibility required of experts.Comment: The Journal of the Learning Sciences (In Press

    Approaching quantum anomalous Hall effect in proximity-coupled YIG/graphene/h-BN sandwich structure

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    Quantum anomalous Hall state is expected to emerge in Dirac electron systems such as graphene under both sufficiently strong exchange and spin-orbit interactions. In pristine graphene, neither interaction exists; however, both interactions can be acquired by coupling graphene to a magnetic insulator (MI) as revealed by the anomalous Hall effect. Here, we show enhanced magnetic proximity coupling by sandwiching graphene between a ferrimagnetic insulator yttrium iron garnet (YIG) and hexagonal-boron nitride (h-BN) which also serves as a top gate dielectric. By sweeping the top-gate voltage, we observe Fermi level-dependent anomalous Hall conductance. As the Dirac point is approached from both electron and hole sides, the anomalous Hall conductance reaches 1/4 of the quantum anomalous Hall conductance 2e2/h. The exchange coupling strength is determined to be as high as 27 meV from the transition temperature of the induced magnetic phase. YIG/graphene/h-BN is an excellent heterostructure for demonstrating proximity-induced interactions in two-dimensional electron systems

    Chi

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    Chi gong--An exercise for internal health

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    Is BMI alone a sufficient outcome to evaluate interventions for child obesity?

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    BACKGROUND: BMI is often used to evaluate the effectiveness of childhood obesity interventions, but such interventions may have additional benefits independent of effects on adiposity. We investigated whether benefits to health outcomes following the Mind, Exercise, Nutrition…Do It! (MEND) childhood obesity intervention were independent of or associated with changes in zBMI. METHODS: A total of 79 obese children were measured at baseline; 71 and 42 participants were followed-up at 6 and 12 months respectively, and split into four groups depending on magnitude of change in zBMI. Differences between groups for waist circumference, cardiovascular fitness, physical and sedentary activities, and self-esteem were investigated. RESULTS: Apart from waist circumference and its z-score, there were no differences or trends across zBMI subgroups for any outcome. Independent of the degree of zBMI change, benefits in several parameters were observed in children participating in this obesity intervention. CONCLUSION: We concluded that isolating a single parameter like zBMI change and neglecting other important outcomes is restrictive and may undermine the evaluation of childhood obesity intervention effectiveness

    Doing research with children and young people who do not use speech for communication

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    Despite emphasis in policy on participation of disabled children, we still know relatively little about how to obtain the views of disabled children with significant communication impairment and their views are often overlooked in planning and service provision. This article describes how the views of children who do not use speech were accessed in research aiming to identify disabled children and young people's priorities regarding outcomes of social care and support services. The main challenge was to develop a method that was reliable, non-threatening, enjoyable and relevant to individual children, as well as enabling children to think beyond their everyday life and express what they aspire to

    It\u27s all in the lens: Differences in views on obesity prevention between advocates and policy makers

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    Background: Intervention strategies to reduce obesity include policy and environmental changes that are designed to provide opportunities, support, and cues to help people develop healthier behaviors. Policy changes at the state level are one way to influence access, social norms, and opportunities for better nutrition and increased physical activity among the population. Methods: Ten states were selected for a broad variance in obesity rates and number of enacted obesity prevention policies during the years of 2006–2009. Within the selected states, a purely qualitative study of attitudes of childhood obesity policy using semistructured telephone interviews was conducted. Interviews were conducted with state policy makers who serve on public health committees. A set of six states that had more than eight childhood obesity policies enacted were selected for subsequent qualitative interviews with a convenience sample of well-established advocates. Results: Policy makers in states where there was more childhood obesity policy action believed in the evidence behind obesity policy proposals. Policy makers also varied in the perception of obesity as a constituent priority. The major differences between advocates and policy makers included a disconnect in information dissemination, opposition, and effectiveness of these policies. Conclusions: The findings from this study show differences in perceptions among policy makers in states with a greater number of obesity prevention bills enacted. There are differences among policy makers and advocates regarding the role and effectiveness of state policy on obesity prevention. This presents an opportunity for researchers and practitioners to improve communication and translation of evidence to policy makers, particularly in states with low legislation
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