168 research outputs found
A Multiculturalidade na Urgência Pediátrica, sabia que…
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Bathyal demersal fishes of the Charlie-Gibbs Fracture Zone region (49°–54°N) of the Mid-Atlantic Ridge : III. Results from remotely operated vehicle (ROV) video transects
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Gut and faecal bacterial community of the terrestrial isopod porcellionides pruinosus: potential use for monitoring exposure scenarios
This work aimed to characterize the gut and faeces bacterial communities (BC) of Porcellionides pruinosus using high-throughput
sequencing. Isopods were collected from the field and kept in laboratory conditions similar to those normally applied in
ecotoxicology tests. Faeces and purged guts of isopods (n=3 × 30) were analysed by pyrosequencing the V3-V4 region of 16 S
rRNA encoding gene. Results showed that gut and faecal BCs were dominated by Proteobacteria, particularly by an OTU
(Operational Taxonomic Unit) affiliated to genus Coxiella. Diversity and richness values were statistically higher for faecal BC,
mainly due to the occurrence of several low-abundance phylotypes. These results may reflect faecal carriage of bacterial groups that
cannot settle in the gut. BCs of P. pruinosus comprised: (1) common members of the soil microbiota, (2) bacterial symbionts, (3)
bacteria related to host metabolic/ecological features, and (4) bacterial etiological agents. Comparison of BC of this isopod species
with the BC from other invertebrates revealed common bacterial groups across taxa. The baseline information provided by this
work will assist the design and data interpretation of future ecotoxicological or biomonitoring assays where the analysis of P.
pruinosus BC should be included as an additional indicator.publishe
Eutrophication-threatened aquatic ecosystems : sediment biogeochemical processes towards nutrients control
Strengthening of three-leaf stone masonry walls: an experimental research
The paper summarizes the results of an experimental research carried out on three-leaf masonry walls
of typical granite stone constructions from the North of Portugal. The research aimed at studying the behaviour
under compression of this wall typology, as well as the improvements introduced by common strengthening
techniques applied for the structural rehabilitation of masonry heritage buildings. Ten masonry specimens were
tested, plain or strengthened by transversal tying of the external leaves, with GFRP bars, or/and by injection of
the inner leaf, with a lime-based grout. The results obtained showed that these strengthening techniques were
successful in increasing the compressive strength of the walls and in improving their behaviour under
compressive loads.The authors would like to thank the technical staff of the Structural Laboratory of University of Minho for the help provided. Acknowledgements are also due to the companies Fradical, Mapei and Augusto de Oliveira Ferreira for providing raw materials and workmanship. Finally, the funding provided by the Portuguese Science and Technology Foundation, through the POCI/ECM/58987/2004 project, is gratefully acknowledged
The star formation history of mass-selected galaxies from the VIDEO survey
© 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical SocietyWe measure star formation rates (SFRs) and specific SFRs (SSFRs) of Ks-selected galaxies from the VISTA Deep Extragalactic Observations survey by stacking 1.4 GHz Very Large Array data.We split the sample, which spans 0 < z<3 and stellar masses 108.0 < M*/M⊙ < 1011.5, into elliptical, irregular or starburst galaxies based on their spectral energy distributions. We find that SSFR falls with stellar mass, in agreement with the 'downsizing' paradigm. We consider the dependence of the SSFR-mass slope on redshift: for our full and elliptical samples the slope flattens, but for the irregular and starburst samples the slope is independent of redshift. The rate of SSFR evolution reduces slightly with stellar mass for ellipticals, but irregulars and starbursts co-evolve across stellar masses. Our results for SSFR as a function of stellar mass and redshift are in agreement with those derived from other radio-stacking measurements of mass-selected passive and star-forming galaxies, but inconsistent with those generated from semi-analytic models, which tend to underestimate SFRs and SSFRs. There is a need for deeper high-resolution radio surveys such as those from telescopes like the next-generation MeerKAT in order to probe lower masses at earlier times and to permit direct detections, i.e. to study individual galaxies in detail.Peer reviewe
Stellar masses of SDSS-III/BOSS galaxies at z ~ 0.5 and constraints to galaxy formation models
We calculate stellar masses for ∼400 000 massive luminous galaxies at redshift ∼0.2–0.7 using the first two years of data from the Baryon Oscillation Spectroscopic Survey (BOSS). Stellar masses are obtained by fitting model spectral energy distributions to u, g, r, i, z magnitudes, and simulations with mock galaxies are used to understand how well the templates recover the stellar mass. Accurate BOSS spectroscopic redshifts are used to constrain the fits. We find that the distribution of stellar masses in BOSS is narrow (Δlog M ∼ 0.5 dex) and peaks at about log M/M⊙ ∼ 11.3 (for a Kroupa initial stellar mass function), and that the mass sampling is uniform over the redshift range 0.2–0.6, in agreement with the intended BOSS target selection. The galaxy masses probed by BOSS extend over ∼1012 M⊙, providing unprecedented measurements of the high-mass end of the galaxy mass function. We find that the galaxy number density above ∼2.5 × 1011 M⊙ agrees with previous determinations. We perform a comparison with semi-analytic galaxy formation models tailored to the BOSS target selection and volume, in order to contain incompleteness. The abundance of massive galaxies in the models compare fairly well with the BOSS data, but the models lack galaxies at the massive end. Moreover, no evolution with redshift is detected from ∼0.6 to 0.4 in the data, whereas the abundance of massive galaxies in the models increases to redshift zero. Additionally, BOSS data display colour–magnitude (mass) relations similar to those found in the local Universe, where the most massive galaxies are the reddest. On the other hand, the model colours do not display a dependence on stellar mass, span a narrower range and are typically bluer than the observations. We argue that the lack of a colour–mass relation for massive galaxies in the models is mostly due to metallicity, which is too low in the models
Expression of divIB of Bacillus subtilis during vegetative growth
Expression of the division initiation gene, divIB, of Bacillus subtilis vegetative growth was examined. lacZ fusion studies and transcription start point mapping have established that a sigma A promoter proximal to divIB is utilized in vivo. The -10 region of this promoter, which is located 93 bp upstream of the start codon, has been defined precisely by site-directed mutagenesis that destroys the promoter. Examination of transcripts by Northern (RNA) blotting has shown that there are at least two transcripts for divIB. The established proximal promoter was found to give rise to a very minor transcript which could not be convincingly demonstrated in wild-type cells but which became apparent upon insertion of a plasmid into the chromosome just upstream of this promoter. The major transcript for divIB originated from a site several kb upstream of the gene and is probably the same as the long polycistronic message also traversing the murD-spoVE-murG genes that was identified previously by others (A.D. Henriques, H. de Lencastre, and P.J. Piggot, Biochimie 74:735-748, 1992). Transcription from the proximal promoter alone, in an upstream-deletion mutant strain, provided sufficient DivIB for normal growth and division as well as sporulation
Coulomb dissociation of N 20,21
Neutron-rich light nuclei and their reactions play an important role in the creation of chemical elements. Here, data from a Coulomb dissociation experiment on N20,21 are reported. Relativistic N20,21 ions impinged on a lead target and the Coulomb dissociation cross section was determined in a kinematically complete experiment. Using the detailed balance theorem, the N19(n,γ)N20 and N20(n,γ)N21 excitation functions and thermonuclear reaction rates have been determined. The N19(n,γ)N20 rate is up to a factor of 5 higher at
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