Informació i control en educació matemàtica

En este artículo se analizan dos aspectos clave de la educación matemática: los procesos de información y de control en el marco de la teoria de la instrucción. El artículo se estructura en los siguientes puntos: 1. Introducción: la educación matemática, las variables instructivas y el constructivismo como modelo epistemológico y psicológico. 2. Implementación: acciones, gestión y decisiones. 3. Eficiencia: observación, autorreflexión y evaluación-recursión.In this article we analyse two key aspects of the mathematical education: the processes of information and control within the framework of the theory of instruction. The article is structured as follows: 1. Introduction: mathematical education, instructive variables and constructivism as an epistemological and psycological model. 2. Implementation: actions, management and decisions. 3. Efficiency: observation, selfreflection and evaluation

Qué escuela, para qué inmigrantes. Zonas de procedencia y tipos de escolarización: el caso de Canarias

La distribución de los inmigrantes en el sistema educativo muestra una realidad muy distinta en la geografía española. Las grandes características diferenciadoras serán las que dirijan el desarrollo de este trabajo, haciendo especial referencia en el análisis comparativo al archipiélago canario. No sólo la comunidad autónoma de acogida, sino también la zona de procedencia de los inmigrantes se convierten en elementos esenciales para entender la distribución según niveles educativos y titularidad de los centros. El análisis de esta cuestión y su comparación con el alumnado autóctono nos permitirá distinguir hasta dónde llega la búsqueda de igualdad o de diferencia de los inmigrantes y destacar cuáles son las comunidades autónomas más igualitarias. Asimismo, se cuestionará el sentido de algunas de las políticas y de las prácticas educativas.The data on immigrants in the educational system show us a very different reality in the Spanish geography. The great differentiating characteristics will guide the development of this article, doing special reference to Canary Archipelago in the comparative analysis. Autonomous Community of reception and zone of origin of immigrants are essential elements to understand the distribution according to the educational levels and according to ownership, public or private, of the educative centres. This analysis and its comparison with native students will allow us to distinguish if immigrants search equality or difference in schools. Besides, will stand out which autonomous communities are more egalitarians. Some educative political and practices will be questioned

The Best-or-Worst and the Postdoc problems

We consider two variants of the secretary problem, the\emph{ Best-or-Worst} and the \emph{Postdoc} problems, which are closely related. First, we prove that both variants, in their standard form with binary payoff 1 or 0, share the same optimal stopping rule. We also consider additional cost/perquisites depending on the number of interviewed candidates. In these situations the optimal strategies are very different. Finally, we also focus on the Best-or-Worst variant with different payments depending on whether the selected candidate is the best or the worst

On the classification theorems of almost-Hermitian or homogeneous Kähler structures

A proof by Young tableaux and symmetrizers is given of the classification theorems by Gray and Hervella of almost-Hermitian structures and by Abbena and Garbiero of homogeneous Kähler structures.Partially supported by DGICYT, Spain, under Grant no. BFM2002–00141.Peer reviewe

La Influencia conjunta del uso de geogebra y lápiz y papel en la adquisición de competencias del alumnado

Este estudio forma parte de una investigación en curso sobre la interpretación del comportamiento de los estudiantes de Bachillerato Tecnológico en la resolución de problemas de geometría plana, mediante el análisis de la relación entre el uso de GeoGebra2, la resolución en lápiz y papel y el pensamiento geométrico. El marco teórico se basa principalmente en la teoría de la instrumentación de Rabardel (2001). Proponemos un análisis de los grados de adquisición de los procesos de instrumentación e instrumentalización de los alumnos, las estrategias de resolución en ambos medios y las interacciones entre los distintos agentes involucrados. Pretendemos buscar una relación entre las concepciones de los alumnos y las técnicas que utilizan en las estrategias de resolución de problemas.This study is part of ongoing research on the interpretation of students' behaviors when solving plane geometry problems by analyzing relationships among DGS (GeoGebra) use, paper-and-pencil work and geometrical thinking. Our theoretical framework is based on Rabardel's (2001) instrumental approach to tool use. We propose an analysis of the acquisition degrees of the instrumentation and instrumentalization processes, the resolution strategies in both environments and the interactions between the different agents We seek relationships between students' thinking and their use of techniques by exploring the influence of certain techniques on the students' resolution strategies

Evidence of coupling between the thermal and nonthermal emission in the gamma-ray binary LS I +61 303

The gamma-ray binary LS I +61 303 is composed of a Be star and a compact companion orbiting in an eccentric orbit. Variable flux modulated with the orbital period of ~26.5 d has been detected from radio to very high-energy gamma rays. In addition, the system presents a superorbital variability of the phase and amplitude of the radio outburst with a period of ~4.6 yr. We present optical photometric observations of LS I +61 303 spanning ~1.5 yr and contemporaneous Halpha equivalent width (EW Halpha) data. The optical photometry shows, for the first time, that the known orbital modulation suffers a positive orbital phase shift and an increase in flux for data obtained 1-yr apart. This behavior is similar to that already known at radio wavelengths, indicating that the optical flux follows the superorbital variability as well. The orbital modulation of the EW Halpha presents the already known superorbital flux variability but shows, also for the first time, a positive orbital phase shift. In addition, the optical photometry exhibits a lag of ~0.1-0.2 in orbital phase with respect to the EW Halpha measurements at similar superorbital phases, and presents a lag of ~0.1 and ~0.3 orbital phases with respect noncontemperaneous radio and X-ray outbursts, respectively. The phase shifts detected in the orbital modulation of thermal indicators, such as the optical flux and the EW Halpha, are in line with the observed behavior for nonthermal indicators, such as X-ray or radio emission. This shows that there is a strong coupling between the thermal and nonthermal emission processes in the gamma-ray binary LS I +61 303. The orbital phase lag between the optical flux and the EW Halpha is naturally explained considering different emitting regions in the circumstellar disk, whereas the secular evolution might be caused by the presence of a moving one-armed spiral density wave in the disk.Comment: 4 pages, 3 figures, accepted for publication in A&A (this version matches the published version