117 research outputs found
Análise do panorama da modelagem bim entre os profissionais da construção civil na cidade de João Pessoa - PB
Alternatives to traditional models of project and building planning, management and execution are gaining more and more space in the construction sector in the world scenario. It seeks to optimize production, reduce waste, reduce expenses and increase profits. In the midst of this context, BIM appears as one of the most promising ways to achieve these goals, consolidating itself more and more in the construction industry. The present work has as goal to perform a survey about how this tool is being used in the city of João Pessoa, Paraíba. This, in turn, was carried out through a form that seeks to identify how professionals and companies in the region understand this technology and whether this discernment about BIM is in accordance with its characteristics and what this methodology can provide to its users. It was also sought to verify the expectations that the participants of the research envision for the adoption of this tool over the next years and, in the case of using BIM, to evaluate the complexity of this use within offices and constructors represented in the sampling, according to internationally used parameters.Alternativas aos modelos tradicionais de planejamento, gerenciamento e execução de projetos e obras vem ganhando cada vez mais espaço no setor da construção civil no cenário mundial. Busca-se otimizar a produção, diminuir desperdícios, reduzir gastos e aumentar lucros. Em meio a esse contexto, o BIM aparece como um dos mais promissores caminhos para alcançar esses objetivos, consolidando-se cada vez mais na indústria da construção. O presente trabalho tem como objetivo realizar um levantamento sobre como essa ferramenta tem sido utilizada na cidade de João Pessoa, Paraíba. Este, por sua vez, foi realizado por meio de um formulário que busca identificar como os profissionais e empresas da construção civil da região entendem essa tecnologia e se tal discernimento sobre o BIM está de acordo com suas características e com o que essa metodologia pode fornecer aos seus usuários. Também procurou-se verificar quais as expectativas que os participantes da pesquisa vislumbram para a adoção dessa ferramenta ao longo dos próximos anos e, no caso de uso do BIM, avaliar qual a complexidade dessa utilização dentro dos escritórios e construtoras representados na amostragem, caracterizando-as de acordo com parâmetros utilizados internacionalmente
Clustering of Intermediate Luminosity X-ray selected AGN at z~3
We present the first clustering results of X-ray selected AGN at z~3. Using
Chandra X-ray imaging and UVR optical colors from MUSYC photometry in the
ECDF-S field, we selected a sample of 58 z~3 AGN candidates. From the optical
data we also selected 1385 LBG at 2.8<z< 3.8 with R<25.5. We performed
auto-correlation and cross-correlation analyses, and here we present results
for the clustering amplitudes and dark matter halo masses of each sample. For
the LBG we find a correlation length of r_0,LBG = 6.7 +/- 0.5 Mpc, implying a
bias value of 3.5 +/- 0.3 and dark matter (DM) halo masses of log(Mmin/Msun) =
11.8 +/- 0.1. The AGN-LBG cross-correlation yields r_0,AGN-LBG = 8.7 +/- 1.9
Mpc, implying for AGN at 2.8<z<3.8 a bias value of 5.5 +/- 2.0 and DM halo
masses of log(Mmin/Msun) = 12.6 +0.5/-0.8. Evolution of dark matter halos in
the Lambda CDM cosmology implies that today these z~3 AGN are found in high
mass galaxies with a typical luminosity of 7+4/-2 L*.Comment: Accepted for publication in ApJ Letters. 4 pages, 4 figures (1 in
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Optical Spectroscopy Of X-Ray Sources In The Extended Chandra Deep Field South
We present the first results of our optical spectroscopy program aimed to provide redshifts and identifications for the X-ray sources in the Extended Chandra Deep Field South. A total of 339 sources were targeted using the IMACS spectrograph at the Magellan telescopes and the VIMOS spectrograph at the VLT. We measured redshifts for 186 X-ray sources, including archival data and a literature search. We find that the active galactic nucleus (AGN) host galaxies have on average redder rest-frame optical colors than nonactive galaxies, and that they live mostly in the "green valley." The dependence of the fraction of AGNs that are obscured on both luminosity and redshift is confirmed at high significance and the observed AGN spatial density is compared with the expectations from existing luminosity functions. These AGNs show a significant difference in the mid-IR to X-ray flux ratio for obscured and unobscured AGNs, which can be explained by the effects of dust self-absorption on the former. This difference is larger for lower luminosity sources, which is consistent with the dust opening angle depending on AGN luminosity.National Aeronautics and Space Administration PF8-90055, NAS8-03060NSF AST0407295Spitzer JPL RSA1288440Natural Science and Engineering Research Council of Canada (NSERC)National Academy of SciencesNASA/INTEGRAL NNG05GM79GAstronom
The Multiwavelength Survey By Yale-Chile (MUSYC) Wide K-Band Imaging, Photometric Catalogs, Clustering, And Physical Properties Of Galaxies At Z Similar To 2
We present K-band imaging of two similar to 30' x 30' fields covered by the Multiwavelength Survey by Yale-Chile (MUSYC) Wide NIR Survey. The SDSS 1030+05 and Cast 1255 fields were imaged with the Infrared Side Port Imager (ISPI) on the 4 m Blanco telescope at the Cerro Tololo Inter-American Observatory (CTIO) to a 5 sigma point-source limiting depth of K similar to 20 (Vega). Combining these data with the MUSYC optical UBVRIz imaging, we created multiband K-selected source catalogs for both fields. These catalogs, together with the MUSYC K-band catalog of the Extended Chandra Deep Field South (ECDF-S) field, were used to select K 20 BzK galaxies over an area of 0.71 deg(2). This is the largest area ever surveyed for BzK galaxies. We present number counts, redshift distributions, and stellar masses for our sample of 3261 BzK galaxies (2502 star-forming [sBzK] and 759 passively evolving [pBzK]), as well as reddening and star formation rate estimates for the star-forming BzK systems. We also present two-point angular correlation functions and spatial correlation lengths for both sBzK and pBzK galaxies and show that previous estimates of the correlation function of these galaxies were affected by cosmic variance due to the small areas surveyed. We have measured correlation lengths r(0) of 8.89 +/- 2.03 and 10.82 +/- 1.72 Mpc for sBzK and pBzK galaxies, respectively. This is the first reported measurement of the spatial correlation function of passive BzK galaxies. In the Lambda CDM scenario of galaxy formation, these correlation lengths at z similar to 2 translate into minimum masses of similar to 4 x 10(12) and similar to 9 x 10(12) M(circle dot) for the dark matter halos hosting sBzK and pBzK galaxies, respectively. The clustering properties of the galaxies in our sample are consistent with their being the descendants of bright Lyman break galaxies at z similar to 3, and the progenitors of present-day > 1L* galaxies.Astronom
Spectroscopic Identification of Massive Galaxies at z~2.3 with Strongly Suppressed Star Formation
We present first results of a spectroscopic survey targeting K-selected
galaxies at z=2.0-2.7 using the GNIRS instrument on Gemini-South. We obtained
near-infrared spectra with a wavelength coverage of 1.0-2.5 micron for 26
K-bright galaxies (K<19.7) selected from the MUSYC survey using photometric
redshifts. We successfully derived spectroscopic redshifts for all 26 galaxies
using rest-frame optical emission lines or the redshifted Balmer/4000 Angstrom
break. Twenty galaxies have spectroscopic redshifts in the range 2.0<z<2.7, for
which bright emission lines like Halpha and [OIII] fall in atmospheric windows.
Surprisingly, we detected no emission lines for nine of these 20 galaxies. The
median 2 sigma upper limit on the rest-frame equivalent width of Halpha for
these nine galaxies is ~10 Angstrom. The stellar continuum emission of these
same nine galaxies is best fitted by evolved stellar population models. The
best-fit star formation rate (SFR) is zero for five out of nine galaxies, and
consistent with zero within 1 sigma for the remaining four. Thus, both the
Halpha measurements and the independent stellar continuum modeling imply that
45% of our K-selected galaxies are not forming stars intensely. This high
fraction of galaxies without detected line emission and low SFRs may imply that
the suppression of star formation in massive galaxies occurs at higher redshift
than is predicted by current CDM galaxy formation models. However, obscured
star formation may have been missed, and deep mid-infrared imaging is needed to
clarify this situation.Comment: Accepted for publication in ApJ Letter
Differences between CO- and calcium triplet-derived velocity dispersions in spiral galaxies: evidence for central star formation?
We examine the stellar velocity dispersions (sigma) of a sample of 48
galaxies, 35 of which are spirals, from the Palomar nearby galaxy survey. It is
known that for ultra-luminous infrared galaxies (ULIRGs) and merger remnants
thesigma derived from the near-infrared CO band-heads is smaller than that
measured from optical lines, while no discrepancy between these measurements is
found for early-type galaxies. No such studies are available for spiral
galaxies - the subject of this paper. We used cross-dispersed spectroscopic
data obtained with the Gemini Near-Infrared Spectrograph (GNIRS), with spectral
coverage from 0.85 to 2.5um, to obtain sigma measurements from the 2.29 m
CO band-heads (sigma_{CO}), and the 0.85 um calcium triplet (sigma_{CaT}). For
the spiral galaxies in the sample, we found that sigma_{CO} is smaller than
sigma_{CaT}, with a mean fractional difference of 14.3%. The best fit to the
data is given by sigma_{opt} = (46.0+/-18.1) + (0.85+/-0.12)sigma_{CO}. This
"sigma discrepancy" may be related to the presence of warm dust, as suggested
by a slight correlation between the discrepancy and the infrared luminosity.
This is consistent with studies that have found no sigma-discrepancy in
dust-poor early-type galaxies, and a much larger discrepancy in dusty merger
remnants and ULIRGs. That sigma_{CO}$ is lower than sigma_{opt} may also
indicate the presence of a dynamically cold stellar population component. This
would agree with the spatial correspondence between low sigma_{CO} and
young/intermediate-age stellar populations that has been observed in
spatially-resolved spectroscopy of a handful of galaxies.Comment: Published in MNRAS, 446, 282
Mid-infrared Properties and Color Selection for X-ray Detected AGN in the MUSYC ECDF-S field
We present the mid-infrared colors of X-ray-detected AGN and explore
mid-infrared selection criteria. Using a statistical matching technique, the
likelihood ratio, over 900 IRAC counterparts were identified with a new MUSYC
X-ray source catalog that includes ~1000 published X-ray sources in the Chandra
Deep Field-South and Extended Chandra Deep Field-South. Most X-ray-selected AGN
have IRAC spectral shapes consistent with power-law slopes, f_{nu} ~
nu^{alpha}, and display a wide range of colors, -2 < alpha < 2. Although X-ray
sources typically fit to redder (more negative alpha) power-laws than non-X-ray
detected galaxies, more than 50% do have flat or blue (galaxy-like) spectral
shapes in the observed 3-8 micron band. Only a quarter of the X-ray selected
AGN detected at 24 micron are well fit by featureless red power laws in the
observed 3.6-24 micron, likely the subset of our sample whose infrared spectra
are dominated by emission from the central AGN region. Most IRAC
color-selection criteria fail to identify the majority of X-ray-selected AGN,
finding only the more luminous AGN, the majority of which have broad emission
lines. In deep surveys, these color-selection criteria select 10-20% of the
entire galaxy population and miss many moderate luminosity AGN.Comment: 29 pages, including 7 figures. Accepted for publication in the
Astrophysical Journa
The Origin of Line Emission in Massive z~2.3 Galaxies: Evidence for Cosmic Downsizing of AGN Host Galaxies
Using the Gemini Near-InfraRed Spectrograph (GNIRS), we have assembled a
complete sample of 20 K-selected galaxies at 2.0<z<2.7 with high quality
near-infrared spectra. As described in a previous paper, 9 of these 20 galaxies
have strongly suppressed star formation and no detected emission lines. The
present paper concerns the 11 galaxies with detected Halpha emission, and
studies the origin of the line emission using the GNIRS spectra and follow-up
observations with SINFONI on the VLT. Based on their [NII]/Halpha ratios, the
spatial extent of the line emission and several other diagnostics, we infer
that four of the eleven emission-line galaxies host narrow line active galactic
nuclei (AGNs). The AGN host galaxies have stellar populations ranging from
evolved to star-forming. Combining our sample with a UV-selected galaxy sample
at the same redshift that spans a broader range in stellar mass, we find that
black-hole accretion is more effective at the high-mass end of the galaxy
distribution (~2.9x10^11 Msun) at z~2.3. Furthermore, by comparing our results
with SDSS data, we show that the AGN activity in massive galaxies has decreased
significantly between z~2.3 and z~0. AGNs with similar normalized accretion
rates as those detected in our K-selected galaxies reside in less massive
galaxies (~4.0x10^10 Msun) at low redshift. This is direct evidence for
downsizing of AGN host galaxies. Finally, we speculate that the typical stellar
mass-scale of the actively accreting AGN host galaxies, both at low and at high
redshift, might be similar to the mass-scale at which star-forming galaxies
seem to transform into red, passive systems.Comment: Accepted for publication in the Astrophysical Journa
Subcutaneous phaeohyphomycosis due to Phialemoniopsis ocularis successfully treated by voriconazole
International audienceWe report a case of subcutaneous infection in a 67 year-old Cambodian man who presented with a 5-month history of swelling of the right foot. Histopathology was compatible with phaeohyphomycosis and the hyphomycete Phialemoniopsis ocularis was identified by the means of morphological and molecular techniques. The patient responded well to a 6-month oral treatment with voriconazole alone
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