Photometric observations of Southern Abell Cluster Redshifts Survey Clusters: Structure of galaxies in the inner region of clusters of galaxies

We analyze photometric properties of 1384 cluster galaxies as a function of the normalized distance to cluster center. These galaxies were selected in the central region ($r/r_{200} \leq$ 0.8) of 14 southern Abell clusters chosen from the Southern Abell Cluster Redshifts Survey (SARS). For 507 of these galaxies we also obtained their luminosity profiles. We have studied the morphology-clustercentric distance relation on the basis of the shape parameter $n$ of the S\'ersic's law. We also have analyzed the presence of a possible segregation in magnitude for both, the galaxy total luminosity and that of their components (i.e. the bulge and the disk). Results show a marginal ($2\sigma$ level) decrease of the total luminosity as a function of normalized radius. However, when bulges are analyzed separately, a significant luminosity segregation is found ($3\sigma$ and $2\sigma$ for galaxies in projection and member galaxies respectively). The fraction of bulges brighter than $M_B \leq -22$ is three times larger in the core of clusters than in the outer region. Our analysis of the disk component suggests that disks are, on average, less luminous in the cluster core than at $r/r_{200} \sim 0.8$. In addition, we found that the magnitude-size relation as a function of $r/r_{200}$ indicates (at $2\sigma$ level) that disks are smaller and centrally brighter in the core of clusters. However, the Kormendy relation (the bulge magnitude-size relation) appears to be independent of environment.Comment: To appear in the A

Utilización de videojuegos en la industria y en la educación

Video games are digital products used in different contexts, not necessarily in those of play, because they have characteristics that allow the improvement of many of the videogamers’ skills. This article reviews the trends in the use of video games in industrial and in educational contexts. It also presents some definitions of necessary concepts that will provide us with a better understanding of these digital products. It concludes that video games are important tools due to their ability to generate motiva­tion and engagement, so their application in contexts other than entertainment would be beneficial.Los videojuegos son productos digitales que se vienen aplicando en diversos contextos que no son necesariamente lúdicos dado que contienen características que permiten la mejora de diversas habilidades de parte de los videojugadores. En el presente artículo se realiza una revisión de las tendencias en la aplicación de videojuegos en la industria y en la educación, tomando como marco el modelo MDA (Mechanics, Dynamics y Aesthetics), así como se revisan algunas definiciones de conceptos necesarios para el entendimiento y análisis de estos productos digitales. Al final, se concluye en la impor­tancia de los videojuegos por su capacidad de generar motivación y enfoque, por lo que su aplicación en entornos distintos a los de entretenimiento generaría muchos beneficios

Structure and dynamics of the Shapley Supercluster

We present results of our wide-field redshift survey of galaxies in a 285 square degree region of the Shapley Supercluster (SSC), based on a set of 10529 velocity measurements (including 1201 new ones) on 8632 galaxies obtained from various telescopes and from the literature. Our data reveal that the main plane of the SSC (v~ 14500 km/s) extends further than previous estimates, filling the whole extent of our survey region of 12~degrees by 30~degrees on the sky (30 x 75~h-1 Mpc). There is also a connecting structure associated with the slightly nearer Abell~3571 cluster complex (v~ 12000km/s. These galaxies seem to link two previously identified sheets of galaxies and establish a connection with a third one at V= 15000 km/s near R.A.= 13h. They also tend to fill the gap of galaxies between the foreground Hydra-Centaurus region and the more distant SSC. In the velocity range of the Shapley Supercluster (9000 km/s < cz < 18000 km/s), we found redshift-space overdensities with b\_j < 17.5 of ~5.4 over the 225 square degree central region and ~3.8 in a 192 square degree region excluding rich clusters. Over the large region of our survey, we find that the intercluster galaxies make up 48 per cent of the observed galaxies in the SSC region and, accounting for the different completeness, may contribute nearly twice as much mass as the cluster galaxies. In this paper, we discuss the completeness of the velocity catalogue, the morphology of the supercluster, the global overdensity, and some properties of the individual galaxy clusters in the Supercluster.Comment: Accepted for publication in Astronomy and Astrophysic

Comparacion de metodos de siembra en el cultivo del arroz (Oriza sativa L.)

El presente experimento se realizó en la Granja Experimental de la Universidad Tecnológica del Magdalena: "Gabriel García Márquez", Municipio de Santa Marta, Departamento del Magdalena, Geográficamente la zona está localizada entre 110 111de latitud Norte y 740 071de longitud Oeste, con temperatura promedio de 28° C: precipitación anual de 630 mm y altura de 10 metros sobre el nivel del mar, Ecológicamente el clima correspondiente a esta zona es de "Clima Tropical Cálido", El trabajo consistió en una comparación de métodos de siembra en el cultivo del arroz, Para tal efecto se utilizaron los siguientes tratamientos : Voleo en seco en una densidad de 170 Kg/M, Voleo en seco en una densidad de 150 Kg/M, Trasplante en una densidad de 30 Kg/há en distancias de 20 cm entre plantas y 20 cm entre hileras, Trasplante en una densidad de 30 Kg/há en distancia de 15 cm entre plantas y 15 cm entre hileras, Trasplante en una densidad de 20 Kg/há en distancia de 20 cm entre plantas y 20 cm entre hileras, Trasplante en una densidad de 20 Kg/há en distancia de 15 cm entre plantas y 15 cm entre hileras, Pre germinado en una densidad de 100 Kg/M, Pre germinado en una densidad de 70 Kg/há. El método estadístico utilizado fue un Diseño en bloques al azar con 8 tratamientos y 7 repeticiones, lo que da -un total de 56 parcelas, El área de cada parcela fue de 1 m2 y un área total de 122m2 El tiempo de duración del ensayo fue de 160 días, Respecto a plagas y enfermedades no se presentaron ataques severos, solamente un ataque leve de chinches (pentatomide Ep), Los mejores rendimientos correspondieron a los tratamientos 5 y 3 con una producción de 9,0 y 8,3 toneladas por hectárea respectivamente, La producción más baja se obtuvo en el método de voleo en seco con densidades entre 170 y 150 Kg/há respectivamente

Discovery of a massive X-ray luminous galaxy cluster at z=1.579

We report on the discovery of a very distant galaxy cluster serendipitously detected in the archive of the XMM-Newton mission, within the scope of the XMM-Newton Distant Cluster Project (XDCP). XMMUJ0044.0-2033 was detected at a high significance level (5sigma) as a compact, but significantly extended source in the X-ray data, with a soft-band flux f(r<40")=(1.5+-0.3)x10^(-14) erg/s/cm2. Optical/NIR follow-up observations confirmed the presence of an overdensity of red galaxies matching the X-ray emission. The cluster was spectroscopically confirmed to be at z=1.579 using ground-based VLT/FORS2 spectroscopy. The analysis of the I-H colour-magnitude diagram shows a sequence of red galaxies with a colour range [3.7 < I-H < 4.6] within 1' from the cluster X-ray emission peak. However, the three spectroscopic members (all with complex morphology) have significantly bluer colours relative to the observed red-sequence. In addition, two of the three cluster members have [OII] emission, indicative of on-going star formation. Using the spectroscopic redshift we estimated the X-ray bolometric luminosity, Lbol = 5.8x10^44 erg/s, implying a massive galaxy cluster. This places XMMU J0044.0-2033 at the forefront of massive distant clusters, closing the gap between lower redshift systems and recently discovered proto- and low-mass clusters at z >1.6.Comment: letter to appear in A&

Gamit!: Plataforma para la gamificación basada en un sistema de recompensas para estudiantes universitarios

La gamificación es una técnica que permite utilizar las técnicas que se presentan en los juegos, en contextos distintos a estos. Es por este motivo, que en la actualidad existen varias iniciativas de su aplicación en contextos educativos, buscando impactar la experiencia de los estudiantes mediante la mejora en la motivación y atención de estos. Para una correcta aplicación de la gamificación, es necesario basarse en alguna metodología que ordene y facilite su adopción, así como por una herramienta que dinamice su utilización por parte de los docentes, así como de los estudiantes. Gamit! Es una plataforma tecnológica de gamificación, cuyo valor radica en facilitar la adopción de esta mediante una metodología basada en narrativas

Gastric Antral Vascular Ectasia in Systemic Sclerosis: Current Concepts

Introduction. Gastric antral vascular ectasia (GAVE) is a rare entity with unique endoscopic appearance described as “watermelon stomach.” It has been associated with systemic sclerosis but the pathophysiological changes leading to GAVE have not been explained and still remain uncertain. Methods. Databases Medline, Scopus, Embase, PubMed, and Cochrane were searched for relevant papers. The main search words were “Gastric antral vascular ectasia,” “Watermelon Stomach,” “GAVE,” “Scleroderma,” and “Systemic Sclerosis.” Fifty-four papers were considered for this review. Results. GAVE is a rare entity in the spectrum of manifestations of systemic sclerosis with unknown pathogenesis. Most patients with systemic sclerosis and GAVE present with asymptomatic anemia, iron deficiency anemia, or heavy acute gastrointestinal bleeding. Symptomatic therapy and endoscopic ablation are the first-line of treatment. Surgical approach may be recommended for patients who do not respond to medical or endoscopic therapies. Conclusion. GAVE can be properly diagnosed and treated. Early diagnosis is key in the management of GAVE because it makes symptomatic therapies and endoscopic approaches feasible. A high index of suspicion is critical. Future studies and a critical review of the current findings about GAVE are needed to understand the role of this condition in systemic sclerosis