319 research outputs found
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
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
"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
Effects of Lactobacillus acidophilus D2/CSL on laying hen performance
In order to evaluate the effects of dietary addition of probiotic strain Lactobacillus acidophilus D2/CSL on hen performance and egg quality, 160 commercial Hy-Line Brown pullets, 17 weeks old, were divided in control group (C) (N=80) and treated group (T) (N=80), with 4 alternate replicates of 20 animals each per group. C was fed with a "standard diet", whereas the T group received the same diet with an inclusion of 1x109 CFU kg-1 of Lactobacillus acidophilus D2/CSL (freeze dried cells). The experimental trial lasted 39 weeks after one week of acclimatization. Hen performance and egg quality (egg production, FCR, egg specific gravity, shell thickness, Haugh Units) were recorded. The results show a higher overall egg production (P<0.01) and better FCR (Kg feed intake/Kg saleable eggs) (P<0.05) in the T birds, but no statistically significant differences were observed in egg weight. The eggs from the T birds were characterized by a higher specific gravity (ESG) (P<0.01) and albumen viscosity (Haugh Units) (P<0.05). No significant differences in egg shell thickness were recorded. In conclusion, Lactobacillus acidophilus D2/CSL improved some important parameters in laying hen performance and egg quality
The MAGNUM survey: Positive feedback in the nuclear region of NGC 5643 suggested by MUSE
We study the ionization and kinematics of the ionized gas in the nuclear
region of the barred Seyfert 2 galaxy NGC~5643 using MUSE integral field
observations in the framework of the MAGNUM (Measuring Active Galactic Nuclei
Under MUSE Microscope) survey. The data were used to identify regions with
different ionization conditions and to map the gas density and the dust
extinction. We find evidence for a double sided ionization cone, possibly
collimated by a dusty structure surrounding the nucleus. At the center of the
ionization cone, outflowing ionized gas is revealed as a blueshifted,
asymmetric wing of the [OIII] emission line, up to projected velocity
v(10)~-450 km/s. The outflow is also seen as a diffuse, low luminosity radio
and X-ray jet, with similar extension. The outflowing material points in the
direction of two clumps characterized by prominent line emission with spectra
typical of HII regions, located at the edge of the dust lane of the bar. We
propose that the star formation in the clumps is due to `positive feedback'
induced by gas compression by the nuclear outflow, providing the first
candidate for outflow induced star formation in a Seyfert-like radio quiet AGN.
This suggests that positive feedback may be a relevant mechanism in shaping the
black hole-host galaxy coevolution.Comment: 9 pages, 7 figures, accepted for publication in A&
Resolving the age bimodality of galaxy stellar populations on kpc scales
Galaxies in the local Universe are known to follow bimodal distributions in
the global stellar populations properties. We analyze the distribution of the
local average stellar-population ages of 654,053 sub-galactic regions resolved
on ~1-kpc scales in a volume-corrected sample of 394 galaxies, drawn from the
CALIFA-DR3 integral-field-spectroscopy survey and complemented by SDSS imaging.
We find a bimodal local-age distribution, with an old and a young peak
primarily due to regions in early-type galaxies and star-forming regions of
spirals, respectively. Within spiral galaxies, the older ages of bulges and
inter-arm regions relative to spiral arms support an internal age bimodality.
Although regions of higher stellar-mass surface-density, mu*, are typically
older, mu* alone does not determine the stellar population age and a bimodal
distribution is found at any fixed mu*. We identify an "old ridge" of regions
of age ~9 Gyr, independent of mu*, and a "young sequence" of regions with age
increasing with mu* from 1-1.5 Gyr to 4-5 Gyr. We interpret the former as
regions containing only old stars, and the latter as regions where the relative
contamination of old stellar populations by young stars decreases as mu*
increases. The reason why this bimodal age distribution is not inconsistent
with the unimodal shape of the cosmic-averaged star-formation history is that
i) the dominating contribution by young stars biases the age low with respect
to the average epoch of star formation, and ii) the use of a single average age
per region is unable to represent the full time-extent of the star-formation
history of "young-sequence" regions.Comment: 17 pages, 11 figures, MNRAS accepte
Self-similarity in the chemical evolution of galaxies and the delay-time distribution of SNe Ia
Recent improvements in the age dating of stellar populations and single stars allow us to study the ages and abundance of stars and galaxies with unprecedented accuracy. We here compare the relation between age and α-element abundances for stars in the solar neighborhood to that of local, early-type galaxies. We find these two relations to be very similar. Both fall into two regimes with a shallow slope for ages younger than ~9 Gyr and a steeper slope for ages older than that value. This quantitative similarity seems surprising because of the different types of galaxies and scales involved. For the sample of early-type galaxies we also show that the data are inconsistent with literature delay-time distributions of either single- or double-Gaussian shape. The data are consistent with a power-law delay-time distribution. We thus confirm that the delay-time distribution inferred for the Milky Way from chemical evolution arguments must also apply to massive early-type galaxies. We also offer a tentative explanation for the seeming universality of the age-[α/Fe] relation: it is the manifestation of averaging different stellar populations with varying chemical evolution histories
INSPIRE: INvestigating Stellar Population In RElics II. First Data Release (DR1)
The INvestigating Stellar Population In RElics is an on-going project
targeting 52 ultra-compact massive galaxies at 0.1<z<0.5 with the X-Shooter@VLT
spectrograph (XSH). These objects are the perfect candidates to be 'relics',
massive red-nuggets formed at high-z (z>2) through a short and intense star
formation burst, that evolved passively and undisturbed until the present-day.
Relics provide a unique opportunity to study the mechanisms of star formation
at high-z. In this paper, we present the first INSPIRE Data Release, comprising
19 systems with observations completed in 2020. We use the methods already
presented in the INSPIRE Pilot, but revisiting the 1D spectral extraction. For
these 19 systems, we obtain an estimate of the stellar velocity dispersion,
fitting separately the two UVB and VIS XSH arms at their original resolution.
We estimate [Mg/Fe] abundances via line-index strength and mass-weighted
integrated stellar ages and metallicities with full spectral fitting on the
combined spectrum. Ages are generally old, in agreement with the photometric
ones, and metallicities are almost always super-solar, confirming the
mass-metallicity relation. The [Mg/Fe] ratio is also larger than solar for the
great majority of the galaxies, as expected. We find that 10 objects have
formed more than 75% of their stellar mass (M*) within 3 Gyr from the Big Bang
and classify them as relics. Among these, we identify 4 galaxies which had
already fully assembled their M* by that time. They are therefore `extreme
relics' of the ancient Universe. The INSPIRE DR1 catalogue of 10 known relics
to-date augment by a factor of 3.3 the total number of confirmed relics, also
enlarging the redshift window. It is therefore the largest publicly available
collection. Thanks to the larger number of systems, we can also better quantify
the existence of a 'degree of relicness', already hinted at the Pilot Paper.Comment: (Abstract abridged) 21 pages, 12 figures and 5 tables in the main
body, plus 3 figure and 1 table in the appendix, accepted for publication on
A&A. The associated data are available via the ESO Phase 3 Science Porta
SN 2006oz: rise of a super-luminous supernova observed by the SDSS-II SN Survey
We study SN 2006oz, a newly-recognized member of the class of H-poor,
super-luminous supernovae. We present multi-color light curves from the SDSS-II
SN Survey, that cover the rise time, as well as an optical spectrum that shows
that the explosion occurred at z~0.376. We fitted black body functions to
estimate the temperature and radius evolution of the photosphere and used the
parametrized code SYNOW to model the spectrum. We constructed a bolometric
light curve and compared it with explosion models. The very early light curves
show a dip in the g- and r-bands and a possible initial cooling phase in the
u-band before rising to maximum light. The bolometric light curve shows a
precursor plateau with a duration of 6-10 days in the rest-frame. A lower limit
of M_u < -21.5 can be placed on the absolute peak luminosity of the SN, while
the rise time is constrained to be at least 29 days. During our observations,
the emitting sphere doubled its radius to 2x10^15 cm, while the temperature
remained hot at 15000 K. As for other similar SNe, the spectrum is best modeled
with elements including O II and Mg II, while we tentatively suggest that Fe
III might be present. We suggest that the precursor plateau might be related to
a recombination wave in a circumstellar medium (CSM) and discuss whether this
is a common property of all similar explosions. The subsequent rise can be
equally well described by input from a magnetar or by ejecta-CSM interaction,
but the models are not well constrained owing to the lack of post-maximum
observations, and CSM interaction has difficulties accounting for the precursor
plateau self-consistently. Radioactive decay is less likely to be the mechanism
that powers the luminosity. The host galaxy, detected in deep imaging with the
10 m GTC, is a moderately young and star-forming, but not a starburst, galaxy.
It has an absolute magnitude of M_g = -16.9.Comment: Contains minor changes (of editorial nature) with respect to v1 in
order to match the published version. The abstract has been modified to fit
the arXiv space requirements. 11 pages, 8 figures, 3 table
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