A method of open cluster membership determination

A new method for the determination of open cluster membership based on a cumulative effect is proposed. In the field of a plate the relative x and y coordinate positions of each star with respect to all the other stars are added. The procedure is carried out for two epochs t_1 and t_2 separately, then one sum is subtracted from another. For a field star the differences in its relative coordinate positions of two epochs will be accumulated. For a cluster star, on the contrary, the changes in relative positions of cluster members at t_1 and t_2 will be very small. On the histogram of sums the cluster stars will gather to the left of the diagram, while the field stars will form a tail to the right. The procedure allows us to efficiently discriminate one group from another. The greater the distance between t_1 and t_2 and the more cluster stars present, the greater is the effect. The accumulation method does not require reference stars, determination of centroids and modelling the distribution of field stars, necessary in traditional methods. By the proposed method 240 open clusters have been processed, including stars up to m<13. The membership probabilities have been calculated and compared to those obtained by the most commonly used Vasilevskis-Sanders method. The similarity of the results acquired the two different approaches is satisfactory for the majority of clusters.Comment: 10 pages, 5 figure

Cuáles son las emociones que surgen y/o se incrementan mediante el trabajo colaborativo con el recurso de la pizarra digital en Educación Secundaria

Se parte de la experiencia de las ponentes en la implementación del trabajo colaborativo que utiliza el recurso de la pizarra digital en el aula. A través de entrevistas a psicólogas que trabajan en diferentes EAPs de la periferia de Barcelona y a profesores/as de Secundaria se definen unos indicadores que nos permitirán definir los elementos emocionales que se dan en la ZDP (Zona de Desarrollo Próximo) de Vigotsky mediante el uso de la pizarra digital en el trabajo colaborativo en el aula. Basamos este trabajo en las teorías de Vigotsky para ir un poco más allá y situar la ZDP en el terreno emocional, describiendo en trabajo colaborativo como una interacción entre iguales. Las teorías del aprendizaje de Paulo Freire permiten fundamentar el trabajo de investigación que se plantea a los grupos de alumnos/as y las teorías Michael Cole & Silvia Scribner nos permiten situar el trabajo colaborativo en el ámbito de las capacidades a desarrollar, las llamadas habilidades comunicativas.The present research is based on the experience of the lecturers in the implementation of collaborative work that uses the resource of the digital whiteboard in the classroom. Through interviews with psychologists working in different EAPs on the outskirts of Barcelona and high school teachers, some indicators have been determined that will allow us to define the emotional elements that occur in the ZPD (Zone of Proximal Development) by Vygotsky through the collaborative work with the digital whiteboard in the classroom. We base this work on the theories of Vygotsky to go a little further and put the ZPD in the emotional field, describing in collaborative work as a peer interaction. According to the learning theories of Paulo Freire we propose this research. Moreover, Michael Cole & Sylvia Scribner theories enable us to situate the collaborative work in the area of skills to develop: the communicative skills

¿Cuáles son las emociones que expresan los alumnos y alumnas de Bachillerato, derivadas de la Literatura?

Esta es una investigación que tiene como objetivo poner de manifiesto las emociones que los chicos y chicas de Bachillerato expresan mediante la lectura de obras literarias que han leído a lo largo de los dos cursos de Bachillerato. La investigación que sepresenta fue realizada a lo largo del curso 2014/15 en el Instituto Las Viñas de Santa Coloma de Gramenet. Las técnicas de recogida de datos y análisis pertenecen al estudio cualitativo de la realidad. Los datos recogidos se basan en la participación de los y lasadolescentes, estudiantes Bachillerato. En esta investigación nos hemos acercado a las opiniones de los alumnos y alumnas de Bachillerato y les hemos preguntado sobre las emociones que han experimentado en las lecturas realizadas a lo largo de primer ysegundo curso de Bachillerato. Este fue un trabajo para el Master Arte y Humanidades de la UOC en la asignatura de Metodología de la Ciencias Humanas del curso 2014/2015.This is a research that aims to highlight the emotions expressed by high school students by Reading literary Works made in the last two academic years. Theresearch presented was carried out during the 2014/15 academic year at "Institute Les Vinyes" in the city of Santa Coloma de Gramenet (Barcelona). We used qualitative research techniques to collect data. The participation of high school students has allowed us to collect data through its opinions. In this research, we approach the emotions that high-school students have expressed and experienced by the readings were performed during the first and second year of highschool. This was a work of the Master of Arts and Humanities at the UOC course Methodology of Humanities 2014/2015

Analysis of Moon impact flashes detected during the 2012 and 2013 Perseids

We present the results of our Moon impact flashes detection campaigns performed around the maximum activity period of the Perseid meteor shower in 2012 and 2013. Just one flash produced by a Perseid meteoroid was detected in 2012 because of very unfavourable geometric conditions, but 12 of these were confirmed in 2013. The visual magnitude of the flashes ranged between 6.6 and 9.3. A luminous efficiency of 1.8 $\times$ 10$^{-3}$ has been estimated for meteoroids from this stream. According to this value, impactor masses would range between 1.9 and 190 g. In addition, we propose a criterion to establish, from a statistical point of view, the likely origin of impact flashes recorded on the lunar surface.Comment: Accepted for publication in Astronomy and Astrophysics on March 11, 201

The 2011 October Draconids Outburst. II. Meteoroid Chemical Abundances from Fireball Spectroscopy

On October 8, 2011 the Earth crossed dust trails ejected from comet 21P/Giacobini-Zinner in the late 19th and early 20th Century. This gave rise to an outburst in the activity of the October Draconid meteor shower, and an international team was organized to analyze this event. The SPanish Meteor Network (SPMN) joined this initiative and recorded the October Draconids by means of low light level CCD cameras. In addition, spectroscopic observations were carried out. Tens of multi-station meteor trails were recorded, including an extraordinarily bright October Draconid fireball (absolute mag. -10.5) that was simultaneously imaged from three SPMN meteor ob-serving stations located in Andalusia. Its spectrum was obtained, showing a clear evolution in the relative intensity of emission lines as the fireball penetrated deeper into the atmosphere. Here we focus on the analysis of this remarkable spectrum, but also discuss the atmospheric trajectory, atmospheric penetration, and orbital data computed for this bolide which was probably released during 21P/Giacobini-Zinner return to perihelion in 1907. The spectrum is discussed together with the tensile strength for the October Draconid meteoroids. The chemical profile evolution of the main rocky elements for this extremely bright bolide is compared with the elemental abundances obtained for 5 October Draconid fireballs also recorded during our spectroscopic campaign but observed only at a single station. Significant chemical heterogeneity between the small meteoroids is found as we should expect for cometary aggregates being formed by diverse dust components.Comment: Manuscript in press in Monthly Notices of the Royal Astronomical Society. Accepted for publication in MNRAS on April 28th, 2013 Manuscript Pages: 28 Tables: 5 Figures: 12. Manuscript associated: "The 2011 October Draconids outburst. I. Orbital elements, meteoroid fluxes and 21P/Giacobini-Zinner delivered mass to Earth" by Trigo-Rodriguez et al. is also in press in the same journa

Microestructura y propiedades mecánicas del material masivo superconductor YBCO a 300 Y 77 K.

En este trabajo se realiza una caracterización mecánica y microestructural del material masivo superconductor YBCO. El material ha sido procesado mediante dos técnicas distintas, Top-Seeding Melt Growth (TSMG) y Bridgman, y este estudio profundiza en el efecto de la microestructura, el método de procesado y la temperatura de ensayo en el comportamiento mecánico de material. Con el fin de conseguir un amplio conocimiento de sus propiedades mecánicas se han realizado ensayos de resistencia a flexión, tenacidad de fractura y dureza Vickers a 300 y 77 K. Asimismo, se llevaron a cabo ensayos de nanoindentación y el tamaño crítico del defecto semielíptico. Los resultados obtenidos muestran que el comportamiento mecánico de los dos materiales está controlado por defectos y grietas, introducidas durante el procesado. También se ha encontrado un buen acuerdo entre el tamaño del defecto critico detectado experimentalmente con los valores obtenidos mediante de análisis de mecánica de fractura

Comportamiento mecánico de materiales masivos superconductores de segunda generación en función de la temperatura

En este trabajo se han analizado dos materiales masivos superconductores de base YBaCuO, con el objetivo de analizar la influencia del método de procesado (método de Bridgman y método Top-Seeding melt growth) y de la temperatura de ensayo en su comportamiento mecánico. Ambos materiales se ensayaron a temperatura ambiente (300 K) y a baja temperatura (77 K), realizándose ensayos rotura y de tenacidad de fractura en flexión en tres puntos. Además, en uno de los materiales, que presentaba anisotropía microestructural, se realizaron ensayos en las dos direcciones microestructuralmente más relevantes. Los resultados obtenidos muestran que el comportamiento mecánico del material está controlado por los defectos y grietas introducidas durante el procesado y, por lo tanto, si se quiere mejorar las propiedades, debería reducirse la cantidad y el tamaño de estas imperfeccione