Caracterización de las concepciones de probabilidad: un estudio realizado con estudiantes de secundaria

Este es un documento realizado para todos aquellos interesados en el estudio del concepto de probabilidad, específicamente a los docentes que revelen algún interés por la enseñanza y el aprendizaje de este objeto matemático en el trabajo con estudiantes de secundaria. El objetivo es diseñar e implementar una secuencia de actividades para estudiantes del grado undécimo (énfasis en matemáticas y sociales) del Instituto Pedagógico Nacional, que les permita identificar, caracterizar y establecer relaciones entre las concepciones de la probabilidad que subyacen en un suceso aleatorio. Finalmente se plantea una propuesta para el trabajo de las concepciones de la probabilidad en un ámbito escolar de educación media. Lo cual se determinó con base en la interpretación de soluciones propuestas por estudiantes entre 15 y 17 que participaban en el estudio de la probabilidad en el grado undécimo del Instituto Pedagógico Nacional

Technical-Economic Evaluation of Residential Wind and Photovoltaic Systems with Self-Consumption and Storage Systems in Portugal

At present, a worldwide paradigm shift has become apparent, with more and more consumers consuming the energy generated by renewable energy sources (RES) systems, such as wind or photovoltaic (PV) energy, sometimes benefiting from appropriate incentives by individual governments. Consequently, it is necessary to carry out technical–economic assessments to understand the evolution of the viability of RES investments. Within the framework of an intelligent network control environment, the smart grid (SG) concept is associated with this model, and is an important tool in the management of energy distribution networks. This article aims to make a further contribution to this issue by analyzing the economic feasibility of investing in residential consumers, considering different RES configurations. Scenarios covered in this study include: “inject all on the low voltage network/consume all on the low voltage network”, self-consumption, net-metering, and storage systems. The economic study results in this article show that self-consumption with and without the injection of excess electricity into the grid is quite attractive. The bi-hourly tariff was found to be more profitable than other tariffs. Variable tariffs (bi or tri-hourly) are more profitable than fixed tariffs. It is also concluded that investment in storage systems is not yet an economically viable solution due to the high price of energy storage.info:eu-repo/semantics/publishedVersio

The Binary Nature of PSR J2032+4127

PSR J2032+4127 is a gamma-ray and radio-emitting pulsar which has been regarded as a young luminous isolated neutron star. However, its recent spin-down rate has extraordinarily increased by a factor of two. We present evidence that this is due to its motion as a member of a highly-eccentric binary system with a 15-solar-mass Be star, MT91~213. Timing observations show that, not only are the positions of the two stars coincident within 0.4 arcsec, but timing models of binary motion of the pulsar fit the data much better than a model of a young isolated pulsar. MT91~213, and hence the pulsar, lie in the Cyg~OB2 stellar association, which is at a distance of only 1.4-1.7 kpc. The pulsar is currently on the near side of, and accelerating towards, the Be star, with an orbital period of 20-30 years. The next periastron is well-constrained to occur in early 2018, providing an opportunity to observe enhanced high-energy emission as seen in other Be-star binary systems.Comment: 8 pages, 5 figures. Accepted for publication in MNRA

La superación del ¡atascado! desde la heurística: un estudio en una comunidad de estudiantes para profesor de matemáticas

Esta investigación hace parte de una serie de trabajos de grado en la implementación de la línea de investigación de la transición del pensamiento matemático elemental al pensamiento matemático avanzado del grupo de investigación de Matemáticas Escolares de la Universidad Distrital (MESCUD). Además, tiene como fin dar cuenta del proceso de resolución de problemas en una comunidad, conformada por un grupo de estudiantes para profesor de la Universidad Distrital Francisco José de Caldas, con el fin de determinar las herramientas heurísticas que permiten superar un ¡Atascado!