Variation with density of the transport properties of YBaCuO superconductors

Abstract

The dependence of the normal-state resistivity, resistive superconducting transition (T _c, ΔT _c), and of the upper critical-field slope (dH _c2/dT|T=T_c) on density has been investigated for several YBa₂Cu₃O_9-x(x?2.1) samples. The resistivity decreases rapidly with increasing density, whereas T _c and ΔT _c are rather insensitive to a change in density. dH _c2/dT|T_c depends sensitively on the preparation conditions. The implications of these results both for the evaluation of the parameters relevant to the understanding of the nature of superconductivity and for the technological applications of granular superconductors are briefly discussed.     

How immigrant adolescents' self‐views in school and family context relate to academic success in Germany

Immigrants' sense of self can be derived both from being members of their ethnic in‐group and their country of residence. We examined how the ways in which immigrant adolescents integrate these self‐views in relation to academic success in German schools. Students describe themselves at school and when with family. Using a standardized literacy performance test, analyses revealed that immigrants whose school‐related self‐view did not include Germany were less successful: Students who described their self as including both aspects of their ethnic group and Germany, and students who saw themselves predominantly as German, outperformed students with purely ethnic school‐related selves. As expected, though, an ethnic family‐related self‐view did not have a negative impact on scholastic achievements.     

Psychometric Evidence of a Multidimensional Measure of Prosocial Behaviors for Spanish Adolescents

Prior theories and scholars rarely distinguished between distinct forms of prosocial behaviors (i.e., actions intended to benefit others) and most scholars operationalize prosocial behaviors as a global construct. Furthermore, stringent tests of psychometric properties of prosocial behavior measures are rare, especially in countries other than the United States. The present study was designed to examine the structure and functions of a multidimensional measure of prosocial behaviors in youth from Spain. Six hundred and 66 adolescents (46% girls; M age = 15.33 years, SD = 0.47 years) from Valencia, Spain, completed the Prosocial Tendencies Measure-Revised (PTM-R), measures of sympathy, perspective taking, and a global measure of prosocial behavior. Results showed that the hypothesized 6-factor structure of the PTM-R had good fit, the best fit model as compared to alternative models, and that there were several unique patterns of relations between specific forms of prosocial behaviors and sympathy, perspective taking, and the global measure of prosocial behavior. Furthermore, although there were significant gender differences in some forms of prosocial behaviors, the structure of the PTM-R was equivalent across gender. Discussion focuses on the implications for theories and measurement of prosocial behaviors.     

To Pass or Not to Pass: A Mathematical Model for Competitive Interactions in Rugby Union

ABSTRACT. Predicting behavior has been a main challenge in human movement science. An important step within the theory of coordination dynamics is to find out the rules that govern human behavior by defining order parameters and control parameters that support mathematical models to predict the behavior of a system. Models to describe human coordination have been focused on interlimb coordination and on interpersonal coordination in affiliative tasks but not on competitive tasks. This article aims to present a formal model with two attractors to describe the interactive behavior on a 2v1 system in rugby union. Interpersonal distance and relative velocity critical values were empirically identified and were included as task constraints that define the attractor landscape. It is shown that using relative velocity as a control parameter the model offers reasonable prediction concerning the decision-making process. The model has the plasticity to adapt to other settings where interpersonal distances and relative velocities amongst system components act as significant task constraints.     

The Effects of Eight-Month Physical Activity Intervention on Vigilance Performance in Adult Obese Population

We aim to analyze the effects of an 8-month physical activity intervention on cardiorespiratory fitness, body mass index (BMI), and vigilance performance in an adult obese population. We conducted an 8-month physical activity intervention based on dance and rhythmic activities. The weekly frequency was 2 sessions of 1 hr per day. Training sessions were divided into 3 phases: a 10-min warm-up, 40 min of dance and rhythmic activities, and 10 min to cool-down. To assess cardiorespiratory fitness, participants performed a modified version of the 6-min walk test from the Senior Fitness Test battery (Larsson & Mattsson, 2001; Rikli & Jones, 1999). Vigilance performance was measured by means of the psychomotor vigilance task (PVT). Two measurements were performed immediately before and after the intervention. The results revealed that participants improved their cardiorespiratory fitness, BMI, and vigilance performance after the intervention. All in all, findings contribute new empirical evidence to the field that investigates the benefits of physical activity intervention on cognitive processes in obese population.     

How Students Learn to Moderate Group Work: The Role of Enjoyment and Boredom

Fostering oral communication competences constitutes a primary goal of higher education. However, research on the acquisition process is sparse, especially when the role of learning-related emotions is considered. Based on control-value theory, this study therefore investigated the interplay between learning-related boredom and enjoyment and the build-up of moderation competence throughout an university course to foster oral competences. A longitudinal quasi-experimental study with two teaching conditions was conducted. About 160 students were assigned either to a control group (CG: autonomy supportive teaching enriched with basic levels of competence support and relatedness support) or an experimental group (EG: autonomy supportive teaching enriched with high levels of competence support and relatedness support). Perceived moderation competence and emotions were assessed three times (T) by self-report: after completion of the course introduction (T1), half way (T2), and at the end of the course (T3). The students’ behavioral performance during a practical moderation exam was graded at T3. Path analyses revealed differential effects of enjoyment and boredom on students’ perceived moderation competence and their grades over time: an activating, learning-enhancing effect of enjoyment on moderation competence was demonstrated, especially if teachers supported students’ experience of autonomy, competence, and relatedness. Boredom, in contrast, had a detrimental effect on the behavioral performance in the practical moderation exam.     

Learning to Live with OCD: Labeling,the Self,and Stigma

Researchers have long questioned relationships among self-conceptions, “mental illness,” and stigma. This article looks at these issues through the lens of Obsessive-Compulsive Disorder (OCD), as minimal research has focused on the lived experience of OCD. We examine the impact of OCD on constructions of identity and the management/resistance of stigma. We do this through in-depth interviews with an untraditional Internet-based sample. We find respondents experience a crisis of self that leads them to a variety of strategies to deal with self-stigma, experienced stigma, and anticipated stigma.     

Self-Induced Water Intoxication in a Psychiatric Asylum: A Case Study of Diagnostic Categorization and Regulation

In this article, we examine the regulation of psychiatric patients becoming intoxicated from drinking excessive amounts of liquids at a large psychiatric asylum in Canada. We analyze how medical staff created a formalized diagnostic category and a specialized ward for its treatment. We consider the institutional context in which “water intoxication” was developed as a diagnostic category and we examine the impact of this diagnosis on the regulation of asylum patients. Finally, we discuss the patients’ opposition to treatment as well as the impact of “water intoxication” on their self-identity and institutional status.