The stellar population and the evolutionary state of HII regions and starburst galaxies

RHII and starbursts are both powered by massive stars. They are the main contributors to the heating of the ISM via radiative and mechanical energy. Techniques to derive the stellar content and the evolutionary state of RHIIs and starbursts from their ultraviolet and optical integrated light are reviewed. A prototypical RHII (NGC 604) and nuclear starburst (NGC 7714) are discussed in more detail. The results reveal the necessity of multiwavelength analyses of these objects to estimate their stellar content and their evolutionary state in a consistent way.Comment: Proceedings of the JENAM Conference (Toulouse, September 1999). To be published in New Astronomy Reviews, Editors Daniel Schaerer and Rosa Gonzalez Delgado. 12 pages, 7 figure

A VLT study of metal-rich extragalactic H II regions. I. Observations and empirical abundances

We have obtained spectroscopic observations from 3600 Angstrom to 9200 Angstrom with FORS at the Very Large Telescope for approximately 70 H II regions located in the spiral galaxies NGC 1232, NGC 1365, NGC 2903, NGC 2997 and NGC 5236. These data are part of a project aiming at measuring the chemical abundances and characterizing the massive stellar content of metal-rich extragalactic H II regions. In this paper we describe our dataset, and present emission line fluxes for the whole sample. In 32 H II regions we measure at least one of the following auroral lines: [S II]4072, [N II]5755, [S III]6312 and [O II]7325. From these we derive electron temperatures, as well as oxygen, nitrogen and sulphur abundances, using classical empirical methods (both so-called "Te-based methods" and "strong line methods"). Under the assumption that the temperature gradient does not introduce severe biases, we find that the most metal-rich nebulae with detected auroral lines are found at 12+log(O/H)~8.9, i.e. about 60% larger than the adopted solar value. However, classical abundance determinations in metal-rich H II regions may be severely biased and must be tested with realistic photoionization models. The spectroscopic observations presented in this paper will serve as a homogeneous and high-quality database for such purpose.Comment: Accepted for publication in Astronomy and Astrophysic

Facebook : herramienta didáctica para el aprendizaje de la geografía

El uso de Internet, más concretamente las redes sociales, se han introducido de forma dominante en la vida cotidiana de jóvenes y adultos hasta convertirse en un elemento casi indispensable, que ha provocado cambios relevantes en su esfera social y personal. Muchos han sido los intentos de utilizar esta herramienta en la docencia aunque en su mayor parte se han circunscrito al nivel universitario o a actividades académicas aisladas, siendo prácticamente inexistente su uso en la Educación Secundaria Obligatoria. Con objeto de explorar las posibilidades que ofrecen las redes sociales para la enseñanza y aprendizaje en las aulas, se analiza la capacidad de Facebook -por ser la más conocida y usada entre los adolescentes- como herramienta didáctica para la docencia de la Geografía en la Educación Secundaria. Para ello se ha realizado un estudio de campo con objeto de comprobar la intensidad de su utilización entre los estudiantes de secundaria en cuatro centros educativos de la isla de Tenerife y, a un total de 302 alumnos, con la finalidad de constatar la viabilidad de su uso. Posteriormente se plantea una propuesta práctica de uso y funcionamiento de esta red social utilizando como ejemplo una unidad didáctica de tercer curso de la Educación Secundaria Obligatoria (E.S.O.).The use of Internet and specifically, the social networks are very important in the daily life of the younger and adult people. Nowadays is a indispensable element that it has caused changes in the social and personal sphere. In the many universitys, this web tool is being used for teaching but, in the high school her use it is nonexistente. With the object to explore the posibility that the social networks offers to teach and to learn in the classtroom, it analyzed the Facebook -more known and used by teenagers- as a tool to teach Geography in the high school. For that, it has conducted a field study in four highs schools in Tenerife, Canary Islands, with a cuantitative methods (surveys) with the object to check the use of Facebook in the young people. Later, it arises a practical proposal explaining her use and operations with the social networks. We use the didactic unit for third course of the secondary education