Plasticity of human handedness: Decreased one-hand bias and inter-manual performance asymmetry in expert basketball players

Abstract

Athletes frequently have to adapt their skills to fast changes of play, often requiring the flexible execution of a particular movement skill with either hand. To assess the influence of sport-specific expertise and extensive sport training on human laterality, a video analysis of regular basketball games was performed for professional, semi-professional, and amateur players to investigate how non-dominant hand use and proficiency change with increasing expertise. Our results showed that the right-hand (i.e. dominant hand) bias in basketball players is reduced with increasing expertise (i.e. competitive level). Accordingly, we found that professional players use their non-dominant hand more often and with greater success than semi-professional and amateur players. This was true for most of the basketball-specific skills. Based on these results, we assume that increasing amounts of bilateral practice can lead to a shift in task-specific manual preference towards a higher use of both hands in competition, as well as to a higher proficiency for non-dominant hand actions in particular. From an applied perspective, the more frequent use and higher proficiency of the non-dominant hand in professional basketball players, compared with amateurs, suggests that the context-specific and skilled use of the non-dominant hand is crucial for successful play at higher competitive levels in the sport of basketball.     

A computational fluid dynamics model for wind simulation: model implementation and experimental validation

To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed in C language based on the Navier-Stokes equations, and it is freely available as open source. Integrated with the spatial analysis and modelling tool (SAMT), the wind model has convenient input preparation and powerful output visualization. To validate the wind model, a series of experiments was conducted in a wind tunnel. A blocking inflow experiment was designed to test the performance of the model on simulation of basic fluid processes. A round obstacle experiment was designed to check if the model could simulate the influences of the obstacle on wind field. Results show that measured and simulated wind fields have high correlations, and the wind model can simulate both the basic processes of the wind and the influences of the obstacle on the wind field. These results show the high reliability of the wind model. A digital elevation model (DEM) of an area (3800 m long and 1700 m wide) in the Xilingele grassland in Inner Mongolia (autonomous region, China) was applied to the model, and a 3D wind field has been successfully generated. The clear implementation of the model and the adequate validation by wind tunnel experiments laid a solid foundation for the prediction and assessment of wind erosion at regional scale.     

Zwischen Wollen, aber nicht k?nnen und K?nnen, aber nicht wollen: übergangsprobleme von Jugendlichen in Japan am Beispiel der ?Freeter“ und ?NEETs“

Die Untersuchung von übergangsprozessen vom Bildungs- in das Besch?ftigungssystem ist vor dem Hintergrund der Jugendarbeitslosigkeit von besonderer Bedeutung. In Japan wird der übergang vielfach als gelungen tituliert. In den letzten Jahren mehren sich allerdings Zeichen, die auf eine ver?nderte Sachlage hindeuten. Der vorliegende Aufsatz analysiert diese Problematik am Beispiel der beiden japanischen Personengruppen „Freeter“ und „NEET“. Dabei handelt es sich um Jugendliche und junge Erwachsene, die nicht (direkt) in ein regul?res Besch?ftigungsverh?ltnis eintreten. Zun?chst werden hier die Ursachen analysiert, dann werden bildungspolitische Ma?nahmen zur Beseitigung der Probleme kommentiert. Durch die Heranziehung von wissenschaftlich fundierten Erkl?rungsans?tzen wird gezeigt, dass sich die beiden genannten Personengruppen durch eine geringe formale Schulqualifikation auszeichnen. Die soziale Herkunft ist hingegen nicht von entscheidender Relevanz, allerdings deutet sich an, dass die finanziellen M?glichkeiten der Eltern hinsichtlich des Besuchs von hochrangigen Bildungsinstitutionen zunehmend an Bedeutung gewinnen. Die in der japanischen ?ffentlichkeit vielfach konstatierten abweichenden Werte und Einstellungen dieser jüngeren Personengruppen lassen sich auf Basis der existenten empirischen Befunde gleichfalls nicht eindeutig fundieren. In der Konsequenz sind Gründe für die übergangsprobleme eher in Zusammenhang mit einer durch die lang anhaltende Wirtschaftskrise angespannten Arbeitsmarktlage auszumachen. Neben einigen Initiativen der Bildungspolitik wird es für Japan daher in Zukunft darauf ankommen, die Integration der schrumpfenden Schul- und Hochschulabg?ngerkohorten effizient zu regulieren.     

Is underestimation less detrimental than overestimation? The impact of experts’ beliefs about a layperson’s knowledge on learning and question asking

Although prior research has shown that experts tend to overestimate or underestimate what laypersons actually know, little is known about the specific consequences of biased estimations for communication. To investigate the impact of biased estimations of a layperson’s knowledge on the effectiveness of experts’ explanations, we conducted a web-based dialog experiment with 45 pairs of experts and laypersons. We manipulated the experts’ mental model of the layperson by presenting them either valid information about the layperson’s knowledge or information that was biased towards overestimation or underestimation. Results showed that the experts adopted the biased estimations and adapted their explanations accordingly. Consequently, the laypersons’ learning from the experts’ explanations was impaired when the experts overestimated or underestimated the layperson’s knowledge. In addition, laypersons whose knowledge was overestimated more often generated questions that reflected comprehension problems. Laypersons whose knowledge was underestimated asked mainly for additional information previously not addressed in the explanations. The results suggest that underestimating a learner during the instructional dialog is as detrimental to learning as is the overestimation of a learner’s knowledge. Thus, the provision of effective explanations presupposes an accurate mental model of the learner’s knowledge prerequisites.     

Kein Heimvorteil in der 1. Tischtennisbundesliga der Herren

A home field advantage is given when the home team wins more than half of the games under home conditions. For team sports, this advantage has been well-established in many studies. The present study examines the home field advantage for individual sports on the example of table tennis. Therefore, all games of the men’s first German National League of table tennis (n?=?406) were analyzed for the seasons 2008/2009 to 2012/2013. There was a home field advantage of 51.48?%. A more specific measure for the home field advantage is to look at single games (“best-of-five” modus), where the home teams won more games (2.01 per competition) than the away teams (1.95 per competition). Both results were statistically not significant. A statistically significant correlation between the size of the home field advantage and the number of spectators was found, as well as an advantage by competition rules of the home team in the opening game, whereas the travel distances of the away teams did not affect the results. Accordingly, the home field advantage is less pronounced in individual sports than in team sports. The player’s performance, however, is positively influenced by the social support of home spectators and the specific competition rules.     

Belief in a just world,teacher justice,and student achievement: A multilevel study

The meaning of belief in a just world and students' subjective experience of the justice of their teachers' behavior toward them personally for academic achievement was examined. Sample 1 involved 947 secondary school students from 67 classes (grade levels 9 to 11), and Sample 2 718 students from 48 classes (grade level 9). Multilevel analyses revealed that the more the students believed in a personal just world, the more they felt their teachers' behavior toward them personally to be just and the better grades they received; the association between BJW and student achievement was fully mediated by teacher justice experience. It was concluded that personally experienced teacher justice is a key feature of a school environment that is conducive to student achievement.