Algunas ideas del profesorado sobre aspectos relacionados con la instrucción del concepto de límite funcional

Se muestran los resultados de una encuesta sobre las opiniones del profesorado de Matemáticas de secundaria en Galicia, relativa a la instrucción sobre el concepto de "Límite funcional" En esta comunicación se presentan sólo tres aspectos relacionados con el tema de una investigación más amplia: El profesorado opina sobre el nivel adecuado en que considera se debería impartir la noción de límite de funciones en los itinerarios del Bachillerato o en la ESO; se identifican algunos referentes que utiliza en su introducción, y finalmente, se recuentan instrumentos, técnicas y herramientas que el profesorado utiliza habitualmente en la instrucción de este objeto matemático. Transversalmente se trata de ver en qué grado el contexto general del aula condiciona las estrategias, herramientas y procedimientos

SPITZER observations of the λ Orionis cluster. II. Disks around solar-type and low-mass stars

We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young (~5Myr) λ Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M_⊙ to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars (diskless), stars with optically thick disks, stars with “evolved disks” (with smaller excesses than optically thick disk systems), and “transitional disk” candidates (in which the inner disk is partially or fully cleared). The disk fraction depends on the stellar mass, ranging from ~6% for K-type stars (R_C − J 4). We confirm the dependence of disk fraction on stellar mass in this age range found in other studies. Regarding clustering levels, the overall fraction of disks in the λ Orionis cluster is similar to those reported in other stellar groups with ages normally quoted as ~5Myr

Amorphous CNx layers from neon electron cyclotron resonance plasmas with N2 and CH4 as precursors

© The Electrochemical Society, Inc. 2000. All rights reserved. Except as provided under U.S. copyright law, this work may not be reproduced, resold, distributed, or modified without the express permission of The Electrochemical Society (ECS). The archival version of this work was published in Journal of The Electrochemical Society. Barbadillo, L., Hernández, M. J., Cervera, M. and J. Piqueras. Amorphous CNx layers from neon electron cyclotron resonance plasmas with N2 and CH4 as precursors. Journal of The Electrochemical Society 147.10 (2000): 3864-386

SEQUENTIAL HERBICIDE APPLICATION IN YAMS

SEQUENTIAL HERBICIDE APPLICATION IN YAM

Survival of wild adults of Ceratitis capitata (Wiedemann) under natural winter conditions in north east Spain

The overwintering of the Mediterranean fruit fly (medfly), Ceratitis capitata (Wiedemann) at the northern limits of its geographic distribution is not yet well known. With the aim of estimating the survival rate of medfly adults in northeast Spain under natural winter conditions, a two-winter-season trial was carried out. A control was carried out in a climatic chamber at 25°C. The results showed that medfly adults were unable to survive the entire winter season in the Girona area. Climatic conditions, including the daily minimum temperature, daily maximum temperature and the high rainfall, appeared to be involved in adult mortality in winter

Model-driven in reverse. The practical experience of the AQUA project

Model-Driven Web Engineering (MDWE) is a new paradigm which provides satisfactory results in software development. However, most experiments with MDWE towards the development of software from the requirements to the implementation stages. However, in practice, sometimes software development does not follow this classic path. In this paper, MDWE is presented as a suitable selection in software projects of technological evolution. The AQUA project is a very large and important project which is a fusion of three previous systems. Thus, this project starts with the original code of these three systems. The paper introduces the power of MDWE in this kind of systems.Ministerio de Educación y Ciencia TIN2007-67843-C06_03Ministerio de Educación y Ciencia IN2007-30391-

Steroidal Saponins and Cell Death in Cancer

Steroidal saponins are natural glycosidic compounds of amphiphilic character. Their diverse biological activities are directly related to the variability of their structural constitutive frameworks, aglycones, and sugars. Several studies have demonstrated the therapeutic potential of steroidal saponins by their capacity to induce programmed cell death in different tumor cell lines. The process of cell death is required to maintain cellular and tissular homeostasis; it has been established that disturbances in the balance between cellular proliferation and cell death lead to several pathologies, including cancer. The antitumor activity of steroidal saponins has been intensely studied allowing elucidation of their different molecular mechanisms of action; this knowledge is crucial to the establishment of new therapeutic strategies against cancer

Hypothalamic Integration of Metabolic, Endocrine, and Circadian Signals in Fish: Involvement in the Control of Food Intake

The regulation of food intake in fish is a complex process carried out through several different mechanisms in the central nervous system (CNS) with hypothalamus being the main regulatory center. As in mammals, a complex hypothalamic circuit including two populations of neurons: one co-expressing neuropeptide Y (NPY) and Agouti-related peptide (AgRP) and the second one population co-expressing pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) is involved in the integration of information relating to food intake control. The production and release of these peptides control food intake, and the production results from the integration of information of different nature such as levels of nutrients and hormones as well as circadian signals. The present review summarizes the knowledge and recent findings about the presence and functioning of these mechanisms in fish and their differences vs. the known mammalian model