The gaseous extent of galaxies and the origin of Lyman alpha absorption systems. IV: Lyman alpha absorbers arising in a galaxy group

We present new GHRS observations of Lyman alpha absorption lines associated with a group of galaxies towards the QSO 1545+2101. We have identified eight distinct Lyman alpha absorption features in the spectrum of QSO 1545+2101 at a mean redshift of z=0.2648 with a velocity dispersion of 163 km/s. A group of galaxies is detected in the vicinity of this QSO at a mean redshift of z=0.2645 and velocity dispersion 239 km/s. The identification of discrete absorption systems indicates that they arise in clouds of neutral hydrogen rather than in a diffuse intragroup medium. Our analysis suggests that the Lyman alpha absorption lines are associated with individual galaxies in the group, although a one-to-one relationship between absorbers and galaxies is difficult to establish in such a dense environment.Comment: 16 pages, 3 figures. Accepted for publication in Ap

Water-ice driven activity on Main-Belt Comet P/2010 A2 (LINEAR) ?

The dust ejecta of Main-Belt Comet P/2010 A2 (LINEAR) have been observed with several telescopes at the at the Observatorio del Roque de los Muchachos on La Palma, Spain. Application of an inverse dust tail Monte Carlo method to the images of the dust ejecta from the object indicates that a sustained, likely water-ice driven, activity over some eight months is the mechanism responsible for the formation of the observed tail. The total amount of dust released is estimated to be 5E7 kg, which represents about 0.3% of the nucleus mass. While the event could have been triggered by a collision, this cannot be decided from the currently available data.Comment: Accepted for ApJ Letter

On the genesis of the Haumea system

The scenarios proposed in the literature for the genesis of the system formed by the dwarf planet 136108 Haumea, its two satellites and a group of some 10 bodies (the family) with semimajor axes, eccentricities and inclinations close to Haumea's values, are analysed against collisional, physical, dynamical and statistical arguments in order to assess their likelihood. All scenarios based on collisional events are reviewed under physical arguments and the corresponding formation probabilities in a collisional environment are evaluated according to the collisional evolution model alicandep. An alternative mechanism is proposed based on the potential possibility of (quasi-) independent origin of the family with respect to Haumea and its satellites. As a general conclusion the formation of the Haumea system is a low-probability event in the currently assumed frame for the evolution of the outer Solar system. However, it is possible that current knowledge is missing some key element in the whole story that may contribute to increase the odds for the formation of such a system.Facultad de Ciencias Astronómicas y Geofísica

NGC1600 - Cluster or Field Elliptical?

A study of the galaxy distribution in the field of the elliptical galaxy NGC1600 has been undertaken. Although this galaxy is often classified as a member of a loose group, all the neighbouring galaxies are much fainter and could be taken as satellites of NGC1600. The number density profile of galaxies in the field of this galaxy shows a decline with radius, with evidence of a background at approximately 1.3 Mpc. The density and number density profile are consistent with that found for other isolated early-type galaxies. NGC1600 appears as an extended source in X-rays, and the center of the X-ray emission seems not to coincide with the center of the galaxy. The velocity distribution of neighbouring galaxies has been measured from optical spectroscopic observations and shows that the mean radial velocity is approximately 85 km/s less than that of NGC1600, indicating that the centre of mass could lie outside the galaxy. The velocity dispersion of the `group' is estimated at 429 km/s. The inferred mass of the system is therefore of the order of 10^14 solar masses, a value that corresponds to a large group. NGC1600 therefore shares some similarities, but is not identical to, the `fossil clusters' detected in X-ray surveys. Implications of this result for studies of isolated early-type galaxies are briefly discussed.Comment: 8 pages, 5 figures and 2 table, accepted for publication in the Ap

Transneptunian objects and Centaurs from light curves

We analyze a vast light curve database by obtaining mean rotational properties of the entire sample, determining the spin frequency distribution and comparing those data with a simple model based on hydrostatic equilibrium. For the rotation periods, the mean value obtained is 6.95 h for the whole sample, 6.88 h for the Trans-neptunian objects (TNOs) alone and 6.75 h for the Centaurs. From Maxwellian fits to the rotational frequencies distribution the mean rotation rates are 7.35 h for the entire sample, 7.71 h for the TNOs alone and 8.95 h for the Centaurs. These results are obtained by taking into account the criteria of considering a single-peak light curve for objects with amplitudes lower than 0.15 mag and a double-peak light curve for objects with variability >0.15mag. The best Maxwellian fits were obtained with the threshold between 0.10 and 0.15mag. The mean light-curve amplitude for the entire sample is 0.26 mag, 0.25mag for TNOs only, and 0.26mag for the Centaurs. The amplitude versus Hv correlation clearly indicates that the smaller (and collisionally evolved) objects are more elongated than the bigger ones. From the model results, it appears that hydrostatic equilibrium can explain the statistical results of almost the entire sample, which means hydrostatic equilibrium is probably reached by almost all TNOs in the H range [-1,7]. This implies that for plausible albedos of 0.04 to 0.20, objects with diameters from 300km to even 100km would likely be in equilibrium. Thus, the great majority of objects would qualify as being dwarf planets because they would meet the hydrostatic equilibrium condition. The best model density corresponds to 1100 kg/m3.Comment: 21 pages, 8 figures. Astronomy & Astrophysics, in pres

Effects of discontinued endurance methods on VO2max in judokas

Este estudio tuvo como objetivo investigar el efecto de dos diferentes planes de entrenamiento de resistencia basados en la metodología discontinua (intermitente e interválica), sobre el VO2Máx de atletas Antioqueños de Judo de rendimiento. Para ello, 21 Judokas de la Selección Antioqueña pertenecientes a la categoría Senior (20,43±4,18 años), fueron distribuidos aleatoriamente en tres grupos, dos grupos experimentales y un grupo control. Ambos grupos experimentales entrenaron la resistencia durante 4 semanas con 4 estímulos por semana, uno de los grupos experimentales basó su entrenamiento en el método interválico y el otro en el intermitente. Por su parte, el grupo control no realizó ningún tipo de entrenamiento de la resistencia. No se hallaron diferencias significativas entre pretest y postest de ninguno de los grupos ni experimentales ni el de grupo control (p>0,05). Se concluyó que el entrenamiento de la resistencia basado en métodos discontinuos no produjo diferencias significativas en el VO2Máx

Geographical variation in relative risks associated with cold waves in Spain: The need for a cold wave prevention plan

In general, there are few studies that analyse the impact of low temperatures on mortality and fewer still that use cold-wave-definition thresholds based on epidemiological and non-climatological criteria. Such a threshold definition, which took into account population features such as socio-economic and demographic characteristics, made it possible for a specific threshold temperature to be obtained for each of Spain's 52 provincial capitals in this study. Using generalised linear models with the Poisson regression link, and controlling for trend, autocorrelations and seasonalities of the series, and influenza epidemics, we obtained the impact of low temperatures on mortality in each provincial capital by calculating the relative risks (RRs) and attributable risks (ARs) for natural as well as circulatory and respiratory causes. The study showed higher minimum temperature thresholds in coastal areas, and an overall impact of cold on mortality in Spain due to natural causes RR=1.13 (95% CI: 1.11-1.16), circulatory causes RR=1.18 (95% CI: 1.15-1.22) and respiratory causes RR=1.24 (95% CI: 1.20-1.29) slightly greater than that obtained to date for heat. From a public health standpoint, there is a need for specific cold wave prevention plans at a regional level which would enable mortality attributable to low temperatures to be reduced. These plans have shown themselves to be effective in decreasing heat-related mortality, and we feel that they are essential for reducing cold-related effects on morbidity and mortality.This study was supported by grants: FIS ENPY 1001/13 & SEPY 1037/14 from Spain's Health Research FundS

Mortality attributable to extreme temperatures in Spain: A comparative analysis by city

BACKGROUND: The Low Temperature Days (LTD) have attracted far less attention than that of High Temperature Days (HTD), though its impact on mortality is at least comparable. This lower degree of attention may perhaps be due to the fact that its influence on mortality is less pronounced and longer-term, and that there are other concomitant infectious winters factors. In a climate-change scenario, the studies undertaken to date report differing results. The aim of this study was to analyse mortality attributable to both thermal extremes in Spain's 52 provinces across the period 2000-2009, and estimate the related economic cost to show the benefit or "profitability" of implementing prevention plans against LTD. METHODS: Previous studies enabled us: to obtain the maximum daily temperature above which HTD occurred and the minimum daily temperature below which LTD occurred in the 52 provincial capitals analysed across the same study period; and to calculate the relative and attributable risks (%) associated with daily mortality in each capital. These measures of association were then used to make different calculations to obtain the daily mean mortality attributable to both thermal extremes. To this end, we obtained a summary of the number of degrees whereby the temperature exceeded (excess °C) or fell short (deficit °C) of the threshold temperature for each capital, and calculated the respective number of extreme temperatures days. The economic estimates rated the prevention plans as being 68% effective. RESULTS: Over the period considered, the number of HTD (4373) was higher than the number of LTD (3006) for Spain as a whole. Notwithstanding this, in every provincial capital the mean daily mortality attributable to heat was lower (3deaths/day) than that attributable to cold (3.48deaths/day). In terms of the economic impact of the activation of prevention plans against LTD, these could be assumed to avoid 2.37 deaths on each LTD, which translated as a saving of €0.29M. Similarly, in the case of heat, 2.04 deaths could be assumed to be avoided each day on which the prevention plan against HTD was activated, amounting to a saving of €0.25M. While the economic cost of cold-related mortality across the ten-year period 2000-2009 was €871.7M, that attributable to heat could be put at €1093.2M. CONCLUSION: The effect of extreme temperatures on daily mortality was similar across the study period for Spain overall. The lower number of days with LTD meant, however, that daily cold-related mortality was higher than daily heat-related mortality, thereby making prevention plans against LTD more "profitable" prevention plans against HTD in terms of avoidable mortality.This study was supported by grants FIS ENPY 1001/13 & SEPY 1037/14 from Spain's Health Research Fund.S

Implementación del levantamiento eficiente de fachadas mediante fotogrametría digital automatizada y el uso de software gratuito

The survey of facades is a defendant process in several areas like architectural design and planning. The photogrammetry provides high geometric accuracy and but allows us to see the texture of the object. With the emergence of free software in this area, it turns into one of the most accessible techniques. To demonstrate the potential of this technique, we present here three examples of facade surveys of different types, made with this technique and using free software, using for that an uncalibrated conventional camera. It also includes a study that shows an analysis of the accuracy achievable with this process, and a direct comparison with two conventional surveying instruments. The work shows, therefore, as close-range photogrammetry allows a cheaper and quick, accurate and efficient survey of facades.El levantamiento de fachadas es un proceso demandado en multitud de ámbitos como la planificación arquitectónica y el planeamiento. La fotogrametría ofrece gran precisión geométrica y nos permite visualizar la textura del objeto en cuestión. Con la aparición de software gratuito en este ámbito, ésta se convierte en una de las técnicas más asequibles. Para demostrar las posibilidades de esta metodología, se presentan aquí tres ejemplos de levantamientos de fachadas de distinta tipología, realizados con fotogrametría y mediante la utilización del software gratuito, utilizando para ello una cámara convencional sin calibrar. Además se incluye un estudio en el que se muestra un análisis de la precisión alcanzable con este proceso, y una comparación directa con dos instrumentos topográficos convencionales. El trabajo realizado muestra, por tanto, como la fotogrametría de objeto cercano posibilita el levantamiento de fachadas a un bajo coste y de una forma ágil, precisa y eficiente