Anticipatory strategies of team-handball goalkeepers

This study seeks to discover whether handball goalkeepers employ a general anticipatory strategy when facing long distance throws and the effect of uncertainty on these strategies. Seven goalkeepers and four throwers took part. We used a force platform to analyse the goalkeeper's movements on the basis of reaction forces and two video cameras synchronised at 500 Hz to film the throw using 3D video techniques. The goalkeepers initiated their movement towards the side of the throw 193 ± 67 ms before the release of the ball and when the uncertainty was reduced the time increased to 349 ± 71 ms. The kinematics analysis of their centre of mass indicated that there was an anticipatory strategy of movement with certain modifications when there was greater uncertainty. All the average scores referring to velocity and lateral movement of the goalkeeper's centre of mass are significantly greater than those recorded for the experimental situation with bigger uncertainty. The methodology used has enabled us to tackle the study of anticipation from an analysis of the movement used by goalkeepers to save the ball.     

Estrategias de conteo implicadas en los procesos de adición y sustracción

Resumen

A lo largo del presente trabajo se analizan las diferencias existentes entre los diversos procesos puestos en juego por los sujetos a la hora de cuantificar lo real, destacando de entre ellos el subproceso de cuantificación extensiva métrica y uno de los esquemas básicos que lleva aparejados: el esquema de conteo. A continuación se pasa a analizar las diferentes estrategias utilizadas por nuetros escolares de 1°, 2°, 3° y 4° de E.G.B. cuando aplican este esquema para la resolución de algoritmos de adición y de sustracción, destacando la vinculación entre el desarrollo de las estrategias de conteo y la eficiencia en la solución de estos algoritmos.     

Children’s and adolescents’ thoughts on pollution: cognitive abilities required to understand environmental systems

Pollution phenomena are complex systems in which different parts are integrated by means of causal and temporal relationships. To understand pollution, children must develop some cognitive abilities related to system thinking and temporal and causal inferential reasoning. These cognitive abilities constrain and guide how children understand pollution processes. Hence, ascertaining whether changes among children’s ideas of pollution are related to system thinking and inferential reasoning abilities could be useful in improving environmental education. Eighty participants between 9 and 16 years old were interviewed to evaluate how children explain different aspects of pollution-related systems. From the explanations found in these interviews, three progressive epistemic structures were reconstructed. The three epistemic structures differ in the type of causal and temporal relationship established by the participants and in the mechanisms that the participants used to relate the pollutant to its effects.     

葡萄牙基础教育数学课程标准述评

近年来,诸多国家关注数学课程改革,数学课程标准一再修订.在这样的国际背景下,葡萄牙教育部于2007年颁布了新的<基础教育数学课程标准>.本文主要介绍葡萄牙20世纪80年代以来的教育体制和标准制定的背景,并在阐述新标准结构和具体内容的基础上,分析了葡萄牙当前基础教育数学课程标准的特点,以资借鉴.     

Wage determinants among medical doctors and nurses in Spain

This paper examines the determination of wage rates for health professionals using three well known, and commonly used, econometric techniques: ordinary least squares, instrumental variables, and Heckman’s method. The data come from a graduate survey and the analysis focuses on a regional labor market, due to nationwide information on salaries is absent in Spain. After estimating different wage equations, the results suggest that OLS estimates are preferable. The findings show an important wage premium for medical doctors relative to nurses, but also a wage advantage for workers who are civil servants and a gender wage-gap that favors men. Although the expansion of higher education in Spain has reduced social inequalities in access, the main policy implication from this paper is that social class differences can still persist at the degree level—in the choice of degree—if students of higher socioeconomic status get a place at university in a degree of higher earnings, a fact that is corroborated in this study.