Network structure, self-organization, and the growth of international collaboration in science

Different approaches have been used to analyse international collaboration in science but none can fully explain its rapid growth. Using international co-authorships, we test the hypothesis that international collaboration is a self-organising network. Applying tools from network analysis, the paper shows that the growth of international co-authorships can be explained based on the organising principle of preferential attachment, although the attachment mechanism deviates from an ideal power-law. Several explanations for the deviation are explored, including that of the influence of institutional constraints on the mechanism of self-organisation.     

Analyzing the OECD Indicators Model

The Organization for Economic Co-operation and Development (OECD) has identified an elaborate set of indicators by which to judge aspects of education systems. This paper provides a comparative analysis of the education-related features of 28 high-income countries in terms of three blocks of indicators relating respectively to the contexts, processes and results of each system. Factor analyses showed that several aspects of the OECD model are more complicated than previously thought. For this reason, the OECD faces a choice of enriching the range of indicators or pruning some components to gain parsimony and greater country participation in data collection. The article demonstrates that to the extent that the OECD model holds, education context variables appear to influence costs, resources and school processes. In turn, processes appear to influence results including achievement though in some cases weakly and in other cases surprisingly. Although further changes in the OECD model deserve consideration the article also shows how it has grown substantially in scope, methodological rigor and country participation during the past decade.     

The effects of professional development on science teaching practices and classroom culture

The current science education reform movement emphasizes the importance of professional development as a means of improving student science achievement. Reformers have developed a vision for professional development based upon intensive and sustained training around concrete tasks that is focused on subject‐matter knowledge, connected to specific standards for student performance, and embedded in a systemic context. Using data from a National Science Foundation Teacher Enhancement program called the Local Systemic Change initiative, this study employs hierarchical linear modeling to examine the relationship between professional development and the reformers' vision of teaching practice. The findings indicate that the quantity of professional development in which teachers participate is strongly linked with both inquiry‐based teaching practice and investigative classroom culture. At the individual level, teachers' content preparation also has a powerful influence on teaching practice and classroom culture. At the school level, school socioeconomic status was found to influence practice more substantially than either principal supportiveness or available resources. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 963–980, 2000     

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.