ResumenEl objetivo de este estudio fue analizar la eficacia de los lanzamientos a canasta en baloncesto. Se examinó la relación existente entre la eficacia del tiro a canasta y una serie de variables registradas durante la acción del lanzamiento. La muestra estuvo constituida por un total de 8.471 lanzamientos (217,2±25,4), de 39 partidos de la NBA. El 21,4% de los lanzamientos analizados fueron de 1 punto, el 62,8% de 2 puntos y el 15,7% de 3 puntos. Existe relación estadística significativa entre la eficacia y el rol del jugador ( = 154,34, p< 0,001). Estos resultados ponen de manifiesto la necesidad de realizar el entrenamiento de forma más real, adecuándolo a las características de la competición analizada. Conocer las acciones que permiten conseguir una mayor eficacia en el lanzamiento a canasta en cada competición facilitará a los entrenadores el diseño de las sesiones de entrenamiento.Palabras clave: Baloncesto, lanzamiento, eficacia, análisis notacional, NBA. AbstractThe aim of this research was to analyze shot efficacy in basketball. Examining the relationship that exists between shot efficacy and a series of variables registered during this action. The sample was constituted a total of 8471 shots (217.2±25.4) of 39 games of NBA league. 21.4% of the analyzed shot were free throws, 62.8% were 2-point field goal and 15.7% were 3-point field goal. A significant relationship existed only between shot efficacy and the player position that took the shot the free throw ( 2 (4, N= 1457) = 12.61, p<.01). Point guard and small forwards had higher efficacy than centers. Field goals, in 2-and 3-point shots, the following relationships were found: i) between efficacy and period ( = 154.34, p< .001). These results show the necessity to carry out the training in a realer way, adapting it to the characteristics of the analyzed competition. To know the actions that allow obtaining a bigger effectiveness in basketball shot will facilitate the coaches the design of the sessions of training.

In this paper we explore the ideas that second grade students articulate about functional relationships. We adopt a function-based approach to introduce elementary children to algebraic content. We present results from a design-based research study carried out with 21 second-grade students (approximately 7 years of age). We focus on a lesson from our classroom teaching experiment in which the students were working on solving a problem that involved a linear functional relationship (y=2x). From the analysis of students' written work and classroom video, we illustrate two different approaches that students adopt to express the relationships between © 2015. This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ 2 two quantities. Students show fluency recontextualizing the problem posed, moving between extra-mathematical and intra-mathematical contexts.

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Some errors in the learning of algebra suggest students have difficulties giving meaning to algebraic symbolism. In this paper, we use problem posing in order to analyze the students' capacity to assign meaning to algebraic symbolism and the difficulties that students encounter in this process depending on the characteristics of the algebraic statements given. We designed a written questionnaire composed of eight closed algebraic statements expressed symbolically, which was administered to 55 students who had finished their compulsory education and that had some previous experience in problem posing. In our analysis of the data, we examine both syntactic and semantic structures of the problem posed. We note that in most cases students posed problems with syntactic structures different to those given. They did not include computations within variables, and changed the kinds of relationships connecting variables. Students easily posed problems for statements with additive structures. Other differences in the type of problems posed depend on the characteristics of the given statements.

En este artículo presentamos parte de los resultados de una investigación más amplia cuyo principal objetivo es indagar sobre las estrategias y representaciones que utilizan alumnos de quinto de educación primaria cuando abordan una tarea de generalización basada en un ejemplo genérico. Recogimos información en el aula habitual de un grupo de 20 alumnos del citado curso, mediante una tarea escrita constituida por diez cuestiones que involucran relaciones funcionales entre dos variables. En este artículo mostramos el análisis y resultados de las respuestas a cuatro de esas cuestiones. Destacamos la diversidad de representaciones utilizadas, el uso de diferentes patrones como estrategia más frecuente, y las evidencias obtenidas de la capacidad de generalización de los escolares de quinto de educación primaria.

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This article discusses evidence of 24 fifth graders ' (10-11 year olds')

In this paper we analyze different types and stages of the conjecturing process. A classification of conjectures is discussed. A variety of problems that could lead to conjectures are considered from the didactical point of view. Results from a number of research studies are used to identify and investigate a number of questions related to the theoretical background of conjecturing as well as practical implications in the learning process.