Mapping the star formation history of Mrk86: I. Data and models

We have obtained optical (BVR, [OIII]5007 and Halpha), near infrared (JHK) imaging and long-slit optical spectroscopy for the Blue Compact Dwarf galaxy Mrk86 (NGC2537). In this paper, the first of two, we present optical-near- infrared colors and emission-line fluxes for the currently star-forming regions, intemediate aged starburst and underlying stellar population. We also describe the evolutionary synthesis models used in Paper II. The R and Halpha luminosity distributions of the galaxy star-forming regions show maxima at M_R=-9.5 and L_Halpha=10^37.3 erg s^-1. The underlying stellar population shows an exponential surface brigthness profile with central value, mu_E,0=21.5 mag arcsec^-2, and scale, alpha=0.88 kpc, both measured in the R-band image. In the galaxy outer regions, dominated by this component, no significant color gradients are observed. Finally, a set of evolutionary synthesis models have been developed, covering a wide range in metallicity and burst strength.Comment: 21 pages, 14 figures, 2 landscape tables, accepted for publication in Astronomy & Astrophysics Supplement Series, for higher resolution images see ftp://cutrex.fis.ucm.es/pub/OUT/gil/PAPERS/aa00_I.ps.g

Ventilator-associated Pneumonia After Elective Cardiac Surgery Caused by Pneumocystis Jirovecii

Ventilator-associated pneumonia is a severe complication among patients undergoing cardiac surgery. Although hospital-acquired bacterial pathogens, often multidrug resistant, are the most frequent cause, non-bacterial atypical and opportunistic agents traditionally associated with immunocompromise are increasingly recognized. We describe ventilator-associated pneumonia due to Pneumocystis jirovecii in the absence of traditional risk factors for Pneumocystis pneumonia in a patient after cardiac surgery

A contribution to the selection of emission-line galaxies using narrow-band filters in the optical airglow windows

Emission line galaxies are an invaluable tool for our understanding of the evolution of galaxies in the Universe. Imaging of deep fields with narrow-band filters allows not only the selection of these objects, but also to infer the line flux and the equivalent width of the emission line with some assumptions. The narrow-band filter technique provides homogeneous samples of galaxies in small comoving volumes in the sky. We present an analysis of the selection of emission-line galaxies using narrow-band filters. Different methods of observation are considered: broad-band -- narrow-band filters and two broad-band and one narrow-band filters. We study also the effect of several lines entering simultaneously inside the filters (this is the case of Halpha). In each case the equations to obtain the equivalent width and line flux from the photometry are obtained. Candidates to emission-line objects are selected by their color excess in a magnitude-color diagram. For different narrow-band filters, we compute the mean colors of stars and galaxies, showing that, apart from galaxies, some types of stars could be selected with certain filter sets. We show how to compute the standard deviation of the colors of the objects even in the usual case when there are not enough objects to determine the standard deviation from the data. We present also helpful equations to compute the narrow-band and the broad-band exposure times in order to obtain minimum dispersion in the ratio of fluxes of both bands with minimum total exposure time.Comment: Accepted for publication in PASP 48 pages, 10 figures Corrected typos, fixed references. Updated reference to T

Glicerólisis de oleínas de cacao con lipasa Candida antarctica en un sistema libre de solventes

In this paper we present the valorization of cocoa olein obtained from the acid fat-splitting of soapstocks. The aim is to develop a solvent free process (enzymatically catalyzed) to maximize the production of a final product with high content of monoglycerides (MAG) and diglycerides (DAG). The effect of the enzyme dose, glycerol content, reaction times as well as the modification of the raw material and pressure were studied. The yield of the reaction increased up to 90-95% when using a vacuum of 2-3 mbar at 65 °C, enough to evaporate the water which is generated as a by-product, an enzyme dose of 1% and molar ratio oil:glycerol of 1:2. The highest yield in terms of MAG and DAG production was obtained by starting from a raw material which was rich in free acidity (FFA), rendering oil with 33.4 and 44.2% MAG and DAG, respectively. Short reaction times (6-8 h) were observed compared to previously reported results (24 h).En el presente trabajo se pretende valorizar la oleína vegetal de cacao procedente de la ruptura ácida de las pastas de refinación química. El objetivo es poner a punto un proceso de glicerólisis enzimática en un sistema libre de solventes maximizando la producción de monoglicéridos (MAG) y diglicéridos (DAG). Se ha estudiado el efecto de la dosis de enzima, el contenido de glicerol y el tiempo de reacción, la modificación de la presión de reacción y la composición de la materia prima. Se concluye que el rendimiento de la reacción aumenta hasta el 90-95% cuando se aplica un vacío de 2-3 mbar a 65 ºC suficiente para evaporar el agua que se va generando como producto, una dosis de enzima del 1% y una relación molar aceite:glicerol 1:2. El mayor rendimiento en cuanto a la producción de MAG y DAG se ha conseguido partiendo de una materia prima rica en acidez libre (FFA), obteniéndose un aceite con un 33.4 y 44.2% de MAG y DAG, respectivamente. Se observa que los tiempos de reacción son cortos (6-8h) comparados con los descritos en la bibliografía encontrada (24h)

Observation of Algebraic Time Order for Two-Dimensional Dipolar Excitons

Emergence of algebraic quasi-long-range order is a key feature of superfluid phase transitions at two dimensions. For this reduced dimensionality interactions prevent Bose-Einstein condensation with true long range order, at any finite temperature. Here, we report the occurence of algebraic order in a strongly interacting quantum liquid formed by dipolar excitons confined in a bilayer semiconductor heterostructure. We observe a transition from exponential to algebraic decay of the excitons temporal coherence, accompanied by a universal scaling behaviour of the equation of state. Our results provide strong evidence for a Berezinskii-Kosterlitz-Thouless (BKT) transition in a multi-component boson-like system governed by strong dipolar interactions

Survey for ‘Candidatus Liberibacter’ and ‘Candidatus Phytoplasma’ in Citrus in Chile

The considerable economic losses in citrus associated with ‘Candidatus Liberibacter’ and ‘Candidatus Phytoplasma’ presence have alerted all producing regions of the world. In Chile, none of these bacteria have been reported in citrus species. During the years 2017 and 2019, 258 samples presenting symptoms similar to those associated with the presence of these bacteria were examined. No detection of ‘Ca. Liberibacter’ associated with “huanglongbing” disease was obtained in the tested samples; therefore, this quarantine pest is maintained as absent in Chile. However, 14 plants resulted positive for phytoplasmas enclosed in subgroups 16SrV-A (12 plants) and 16SrXIII-F (2 plants). Although they have been found in other plant species, this is the first report of these phy-toplasmas in citrus worldwide

CO^(12) mapping of the low-metallicity blue compact dwarf galaxy Markarian 86

We have mapped the CO^12 J = 1-0 and J = 2-1 line emission in Markarian 86, one of the most metal-deficient blue compact dwarf galaxies so far detected in CO^12. The CO^12 emission is distributed in a horseshoe-like structure that follows the locus of the most recent star formation regions. The minimum in molecular line emission corresponds to the position of an older, massive nuclear starburst. The H_2 mass of the galaxy [in the range of (0.4-5) x 10^7 M_⨀] and its morphology have been compared with the predictions of hydrodynamic simulations of the evolution of the interstellar medium surrounding a nuclear starburst. These simulations suggest that the physical conditions in the gas swept out by the starburst could have led to the formation of the ring of molecular gas reported here. This result provides an attractive scenario for explaining the propagation (in a galactic scale) of the star formation in dwarf galaxies