The ages and metallicities of galaxies in the local universe

We derive stellar metallicities, light-weighted ages and stellar masses for a magnitude-limited sample of 175,128 galaxies drawn from the Sloan Digital Sky Survey Data Release Two (SDSS DR2). We compute median-likelihood estimates of these parameters using a large library of model spectra at medium-high resolution, covering a comprehensive range of star formation histories. The constraints we derive are set by the simultaneous fit of five spectral absorption features, which are well reproduced by our population synthesis models. By design, these constraints depend only weakly on the alpha/Fe element abundance ratio. Our sample includes galaxies of all types spanning the full range in star formation activity, from dormant early-type to actively star-forming galaxies. We show that, in the mean, galaxies follow a sequence of increasing stellar metallicity, age and stellar mass at increasing 4000AA-break strength (D4000). For galaxies of intermediate mass, stronger Balmer absorption at fixed D4000 is associated with higher metallicity and younger age. We investigate how stellar metallicity and age depend on total galaxy stellar mass. Low-mass galaxies are typically young and metal-poor, massive galaxies old and metal-rich, with a rapid transition between these regimes over the stellar mass range 3x10^9<M/Msun<3x10^10. Both high- and low-concentration galaxies follow these relations, but there is a large dispersion in stellar metallicity at fixed stellar mass, especially for low-concentration galaxies of intermediate mass. Despite the large scatter, the relation between stellar metallicity and stellar mass is similar to the correlation between gas-phase oxygen abundance and stellar mass for star-forming galaxies. [abriged]Comment: 22 pages, 14 figures, accepted for publication on MNRAS, data available at http://www.mpa-garching.mpg.de/SDSS

Gravitational lens candidates in the E-CDFS

We report ten lens candidates in the E-CDFS from the GEMS survey. Nine of the systems are new detections and only one of the candidates is a known lens system. For the most promising five systems including the known lens system, we present results from preliminary lens mass modelling, which tests if the candidates are plausible lens systems. Photometric redshifts of the candidate lens galaxies are obtained from the COMBO-17 galaxy catalog. Stellar masses of the candidate lens galaxies within the Einstein radius are obtained by using the $z$-band luminosity and the $V-z$ color-based stellar mass-to-light ratios. As expected, the lensing masses are found to be larger than the stellar masses of the candidate lens galaxies. These candidates have similar dark matter fractions as compared to lenses in SLACS and COSMOS. They also roughly follow the halo mass-stellar mass relation predicted by the subhalo abundance matching technique. One of the candidate lens galaxies qualifies as a LIRG and may not be a true lens because the arc-like feature in the system is likely to be an active region of star formation in the candidate lens galaxy. Amongst the five best candidates, one is a confirmed lens system, one is a likely lens system, two are less likely to be lenses and the status of one of the candidates is ambiguous. Spectroscopic follow-up of these systems is still required to confirm lensing and/or for more accurate determination of the lens masses and mass density profiles.Comment: 12 pages, 5 figures, 3 tables, ApJ accepte

Microbiological and serological monitoring in hooded crow (Corvus corone cornix) in the Region Lombardia, Italy

The health status of 276 hooded crows (Corvus corone cornix) from various provinces of Lombardy was monitored for three years. Bacteriological examination detected E. coli (76%), Campylobacter jejuni (17%), Salmonella typhimurium (11.6%), Yersinia spp. (6.5%), Clamydophila abortus and C. psittaci (2.6%); from six birds showing severe prostration Pasteurella multocida was isolated. Virological and serological tests were negative for Avian Influenza virus (AIV), West Nile virus (WNV) and only three samples were positive for Newcastle disease virus (NDV) but only at serology (titre 1:16)

Continuous central venous saturation monitoring in critically ill patients

Table 1 (abstract P39). Patients\u2019 variables according to ScvO2 range ScvO2 75 Patients 15/37 36/37 36/37 SpO2 (%) 95.8 \ub1 3.0 95.0 \ub1 3.3 96.4 \ub1 2.3 HR (bpm) 90.6 \ub1 16.1 90.5 \ub1 18.1 90.7 \ub1 16.5 MAP (mmHg) 82.5 \ub1 10.6 83.4 \ub1 12.7 82.2 \ub1 11.7 CVP (mmHg) 18.3 \ub1 4.6 20.2 \ub1 8.2 19.2 \ub1 5.

A new population of recently quenched elliptical galaxies in the SDSS

We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue optical colors. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r\geq2.6). These blue ellipticals comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between 10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra diagnostics, we identify a unique subset of 172 non-star-forming ellipticals with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar ages. These recently quenched ellipticals (RQEs) have a number density of 2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above 2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the expected quiescent growth at late cosmic time assuming this phase lasts 0.5 Gyr. RQEs have properties that are consistent with a recent merger origin (i.e., they are strong `first-generation' elliptical candidates), yet few involved a starburst strong enough to produce an E+A signature. The preferred environment of RQEs (90 per cent reside at the centers of < 3\times 10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale' predicted for maximally efficient spiral merging onto their halo center and rules out satellite-specific quenching processes. The high incidence of Seyfert and LINER activity in RQEs and their plausible descendents may heat the atmospheres of small host halos sufficiently to maintain quenching.Comment: 26 pages, 9 figures. Revised version; accepted for publication in MNRA

On the connection between galactic downsizing and the most fundamental galactic scaling relations

In their evolution, star-forming galaxies are known to follow scaling relations between some fundamental physical quantities, such as the mass-metallicity and the main sequence relations. We aim at studying the evolution of galaxies that, at a given redshift, lie simultaneously on the mass-metallicity and main sequence relations (MZR, MSR). To this aim, we use the analytical, 'leaky-box' chemical evolution model of Spitoni et al. (2017), in which galaxy evolution is described by an infall timescale $\tau$ and a wind efficiency $\lambda$. We provide a detailed analysis of the temporal evolution of galactic metallicity, stellar mass, mass-weighted age and gas fraction. The evolution of the galaxies lying on the MZR and MSR at $z\sim0.1$ suggests that the average infall time-scale in two different bins of stellar masses ($M_{\star}10^{10} M_{\odot}$) decreases with decreasing redshift. This means that at each redshift, only the youngest galaxies can be assembled on the shortest timescales and still belong to the star-forming MSR. In the lowest mass bin, a decrease of the median $\tau$ is accompanied by an increase of the median $\lambda$ value. This implies that systems which have formed at more recent times will need to eject a larger amount of mass to keep their metallicity at low values. Another important result is that galactic downsizing, as traced by the age-mass relation, is naturally recovered by imposing that local galaxies lie on both the MZR and MSR. Finally, we study the evolution of the hosts of C$_{\rm IV}$ -selected AGN, which at $z\sim 2$ follow a flat MZR, as found by Mignoli et al. (2019). If we impose that these systems lie on the MSR, at lower redshifts we find an 'inverted' MZR, meaning that some additional processes must be at play in their evolution.Comment: Accepted for publication in Astronomy and Astrophysics (A&A), 20 pages, 26 figure

The cosmic evolution of the spatially-resolved star formation rate and stellar mass of the CALIFA survey

We investigate the cosmic evolution of the absolute and specific star formation rate (SFR, sSFR) of galaxies as derived from a spatially-resolved study of the stellar populations in a set of 366 nearby galaxies from the CALIFA survey. The analysis combines GALEX and SDSS images with the 4000 break, H_beta, and [MgFe] indices measured from the datacubes, to constrain parametric models for the SFH, which are then used to study the cosmic evolution of the star formation rate density (SFRD), the sSFR, the main sequence of star formation (MSSF), and the stellar mass density (SMD). A delayed-tau model, provides the best results, in good agreement with those obtained from cosmological surveys. Our main results from this model are: a) The time since the onset of the star formation is larger in the inner regions than in the outer ones, while tau is similar or smaller in the inner than in the outer regions. b) The sSFR declines rapidly as the Universe evolves, and faster for early than for late type galaxies, and for the inner than for the outer regions of galaxies. c) SFRD and SMD agree well with results from cosmological surveys. At z< 0.5, most star formation takes place in the outer regions of late spiral galaxies, while at z>2 the inner regions of the progenitors of the current E and S0 are the major contributors to SFRD. d) The inner regions of galaxies are the major contributor to SMD at z> 0.5, growing their mass faster than the outer regions, with a lookback time at 50% SMD of 9 and 6 Gyr for the inner and outer regions. e) The MSSF follows a power-law at high redshift, with the slope evolving with time, but always being sub-linear. f) In agreement with galaxy surveys at different redshifts, the average SFH of CALIFA galaxies indicates that galaxies grow their mass mainly in a mode that is well represented by a delayed-tau model, with the peak at z~2 and an e-folding time of 3.9 Gyr.Comment: 23 pages, 16 figures, 6 tables, accepted for publication in Astronomy & Astrophysics. *Abridged abstract

Estimation of absorption line indices of early-type galaxies using colours

Context. Absorption line indices are widely used to determine the stellar population parameters such as age and metallicity of galaxies, but it is not easy to obtain the line indices of some distant galaxies that have colours available. Aims. This paper investigates the correlations between absorption line indices and colours. Methods. A few statistical fitting methods are mainly used, via both the observational data of Sloan Digital Sky Survey and a widely used theoretical stellar population model. Results. Some correlations between widely used absorption line indices and ugriz colours are found from both observational data of early-type galaxies and a theoretical simple stellar population model. In particular, good correlations between colours and widely used absorption line indices such as Dn(4000), HgammaA, HgammaF, HdeltaA, Mg1, Mg2, and Mgb, are shown in this paper. Conclusions. Some important absorption line indices of early-type galaxies can be estimated from their colours using correlations between absorption line indices and colours. For example, age-sensitive absorption line indices can be estimated from (u-r) or (g-r) colours and metallicity-sensitive ones from (u - z) or (g - z). This is useful for studying the stellar populations of distant galaxies, especially for statistical investigations.Comment: 9 pages, 21 figures, will be shown in A&

A radiological visual scale to predict the potentially recruitable lung in ALI/ARDS patients

Introduction In ALI/ARDS patients the amount of potentially recruitable lung is extremely variable and it is poorly predictable by the changes of oxygenation, carbon dioxide or compliance during a PEEP trial [1]. At the present time the gold standard to compute the lung recruitability is the quantitative lung CT scan, in which each lung image, after being manually drawn, is analyzed by dedicated software. However, this is both a laborious and time-consuming technique. The aim of this study was to evaluate the ability of a visual radiological scale compared with lung CT scan analysis to predict the lung recruitability in ALI/ARDS patients. Methods A whole lung CT scan was performed at 5 and 45 cmH2O airway pressure. For CT scan analysis each lung image was manually outlined and analyzed by a dedicated software. The potentially recruitable lung was defi ned as the proportion of the nonaerated lung tissue in which aeration was restored [1]. For radiological visual scale analysis, two radiologists performed a blinded evaluation of the consolidation/collapsed areas in each lobe by visual inspection [2]. The overall lung change in consolidation/collapsed was obtained by the sum of each lobe and computed as the diff erence between the two conditions. Results Twenty-four ALI/ARDS patients (age 59 \ub1 15 years, BMI 26 \ub1 4 kg/m2, PaO2/FiO2 170 \ub1 60, PEEP 10 \ub1 2 cmH2O) were enrolled. The percentage of potentially recruitable lung was 16.2 \ub1 7.1% and 14.7 \ub1 7.0%, computed by CT scan and by the visual radiological scale, respectively. The mean diff erence between CT scan analysis and visual radiological analysis was 3.3 \ub1 4.6% (median: 2.91, interquartile range: 0.38 to 6.56). The error of the visual method was lower than 5% in 14 patients (58.3%), between 5% and 10% in eight patients (33.3%) and between 10% and 15% in two patients (8.3%). Conclusions The application of a radiological visual scale is able to predict the amount of potentially recruitable lung similarly to those obtained by a dedicated software avoiding the need of manually drawing each lung image. References 1. Gattinoni L, et al.: N Engl J Med 2006, 354:1775-1786. 2. Pierce RJ, et al.: Thorax 1980, 35:773-780

"Solid state charge trapping": Examples of polymer systems showing memory effect

The paper reports on a characteristic property of electroactive materials bearing an electron-rich and an electron-poor moiety, known as charge trapping. As examples of materials that exhibit this phenomenon, films of poly(4,4"-dipentoxy-4\u27-(2,2\u27-dicyano)ethenyl-2,2\u27:5\u27,2"-terthiophene), poly(2,3-dihexylthieno[3,4-b]pyrazine) and a blend between a fulleropyrrolidine derivative and poly(3-hexylthiophene) were investigated by cyclic voltammetry, spectroelectrochemistry and electrochemical quartz crystal microbalance. In the cyclic voltammetry, the reduction processes show the reverse oxidation potential about 1 V higher than the expected value, indicating a strong stabilization of the corresponding anion species. The mechanism leading to the stabilisation of the anions is discussed and the results indicate that the investigated materials exhibit a remarkable and quite stable memory effect