The Star Cluster System of the NGC 7673 Starburst

We investigate the star cluster system in the starburst galaxy NGC 7673 using archival Hubble Space Telescope WFPC2 broad-band images. For the first time we are able to examine the internal structures of the prominent optical clumps in this galaxy. The clumps are composed of young stars, 16-33 % of which are in bright star clusters. We identify 268 star cluster candidates in both the F555W and F814W images, and 50 clusters with the F255W filter. These data allow us to estimate ages and masses using color-magnitude and two-color diagrams for our sample. We find a population of young, < 6 Myr clusters located throughout the galaxy with concentrations in the clumps. Star cluster mass estimates are 5-50 x 10^4 M_solar for the brightest objects. The starburst remains active in physically well-separated regions, indicating a widespread starburst trigger. We discuss clump lifetimes, their implications for the future evolution of NGC 7673, and possible relationships to high redshift starbursts.Comment: 18 pages, 15 figures. Accepted for publication in Astronomy & Astrophysic

Searching for massive pre--stellar cores through observations of N2H+ and N2D+

We have measured the deuterium fractionation (through the column density ratio N(N2D+)/N(N2H+)) and the CO depletion factor (ratio between expected and observed CO abundance) in a sample of 10 high-mass protostellar candidates, in order to understand whether the earliest evolutionary stages of high-mass stars have chemical characteristics similar to those of low-mass ones. The observations were carried out with the IRAM-30m telescope and the JCMT. We have detected N2D+ emission in 7 of the 10 sources of our sample, and found an average value N(N2D+)/N(N2H+)~0.015. This value is 3 orders of magnitude larger than the interstellar D/H ratio, indicating the presence of cold and dense gas, in which the physical-chemical conditions are similar to those observed in low-mass pre-stellar cores. Also, the integrated CO depletion factors show that in the majority of the sources the expected CO abundances are larger than the observed values, with a median ratio of 3.2. In principle, the cold gas that gives origin to the N2D+ emission can be the remnant of the massive molecular core in which the high-mass (proto-)star was born, not yet heated up by the central object. If so, our results indicate that the chemical properties of the clouds in which high-mass stars are born are similar to their low-mass counterparts. Alternatively, this cold gas can be located into one (or more) starless core (cores) near the protostellar object. Due to the poor angular resolution of our data, we cannot decide which is the correct scenario.Comment: 27 pages, 15 figures, accepted by Astronomy and Astrophysic

Are Females More Responsive to Emotional Stimuli? A Neurophysiological Study Across Arousal and Valence Dimensions

Men and women seem to process emotions and react to them differently. Yet, few neurophysiological studies have systematically investigated gender differences in emotional processing. Here, we studied gender differences using Event Related Potentials (ERPs) and Skin Conductance Responses (SCR) recorded from participants who passively viewed emotional pictures selected from the International Affective Picture System (IAPS). The arousal and valence dimension of the stimuli were manipulated orthogonally. The peak amplitude and peak latency of ERP components and SCR were analyzed separately, and the scalp topographies of significant ERP differences were documented. Females responded with enhanced negative components (N100 and N200), in comparison to males, especially to the unpleasant visual stimuli, whereas both genders responded faster to high arousing or unpleasant stimuli. Scalp topographies revealed more pronounced gender differences on central and left hemisphere areas. Our results suggest a difference in the way emotional stimuli are processed by genders: unpleasant and high arousing stimuli evoke greater ERP amplitudes in women relatively to men. It also seems that unpleasant or high arousing stimuli are temporally prioritized during visual processing by both genders

Modes, mechanisms and evidence of bet hedging in rotifer diapause traits

In this contribution, we review our knowledge on bet-hedging strategies associated with rotifer diapause. First, we describe the ecological scenario under which bet hedging is likely to have evolved in three diapause-related traits in monogonont rotifer populations: (1) the timing of sex (because diapausing eggs are produced via sexual reproduction), (2) the sexual reproduction ratio (i.e. the fraction of sexually reproducing females) and (3) the timing of diapausing egg hatching. Then, we describe how to discriminate among bet-hedging modes and discuss which modes and mechanisms better fit the variability observed in these traits in rotifers. Finally, we evaluate the strength of the empirical evidence for bet hedging in the scarce studies available, and we call for the need of research at different levels of biological complexity to fully understand bet hedging in rotifer diapause

CHEOPS (CHaracterizing ExOPlanets Satellite) mission

The Characterizing ExOPlanet Satellite (CHEOPS) mission was selected in October 2012 by ESA as the first small mission. It will be a ultra-high precision photometer dedicated to the observation of transits of known exoplanets on bright stars, for which the mass has already been measured via ground-based spectroscopic surveys. Its precision will allow the accurate determination of the planetary radii and, by consequence, the planetary bulk density. CHEOPS will also unveil transiting exoplanets of interest for in-depth characterization, a legacy for future instruments suited to the spectroscopic characterization of exoplanetary atmospheres.Publisher PD

Pontas evocadas por estímulos somatossensitivos e atividade epileptiforme no eletrencefalograma em crianças "normais" Somatosensory evoked spikes and epileptiform activity in "normal" children

Estudamos a ocorrência de potenciais de alta voltagem evocados por estímulos somatossensitivos - pontas evocadas (PE) - e de atividade epileptiforme espontânea (AE) no EEG de 173 crianças normais de 7 a 11 anos de idade. Durante o EEG, dez percussões foram realizadas nas mãos e pés. Foi avaliada a ocorrência de PE acompanhando cada um dos estímulos e a presença de AE. AE foi observada em quatro crianças (2,3%): pontas centroparietais em duas, complexos de ponta-onda lenta generalizados em uma e pontas parietais e temporais médias em uma. Uma menina de 10 anos de idade (0,58%) teve ao EEG pontas parietais medianas evocadas pela percussão do pé esquerdo. Este EEG era normal quanto a outros aspectos. Nossos achados de AE em crianças normais são similares aos encontrados em estudos de outros países. Constatamos que espículas somatossensitivas podem ser observadas em crianças normais o que sugere uma natureza funcional ligada à idade.<br>Little is known about somatosensory evoked spikes (SES) in the EEG of normal children. We studied the occurrence of SES and spontaneous epileptiform activity (SEA) in 173 normal children ageg 7 to 11 years. During the EEG ten taps were applied to both hands and feet. The occurrence of high voltage potentials evoked by each stimulation of one or both heels or hands (SES) and the occurrence of SEA were evaluated. SEA was observed in four children (2.3 %): central/parietal spikes in two cases, generalized spike-and-wave in one, and parietal/midtemporal spikes in one case. A ten years old girl (0,58%) had SES on median parietal region by tapping the left foot. This EEG was otherwise normal. Our findings of SEA are similar to those obtained in other normal populations. SES can be observed in normal children. These SES suggest that we are dealing with an age-related functional phenomenon

CHEOPS (Characterising Exoplanets Satellite) Mission

peer reviewedThe Characterizing ExOPlanet Satellite (CHEOPS) mission was selected in October 2012 by ESA as the first small mission. It will be a ultra-high precision photometer dedicated to the observation of transits of known exoplanets on bright stars, for which the mass has already been measured via ground-based spectroscopic surveys. Its precision will allow the accurate determination of the planetary radii and, by consequence, the planetary bulk density. CHEOPS will also unveil transit- ing exoplanets of interest for in-depth characterization, a legacy for future instruments suited to the spectroscopic characterization of exoplanetary atmospheres