301 research outputs found
A Census of Star-Forming Galaxies in the z~9-10 Universe based on HST+Spitzer Observations Over 19 CLASH clusters: Three Candidate z~9-10 Galaxies and Improved Constraints on the Star Formation Rate Density at z~9
We utilise a two-color Lyman-Break selection criterion to search for z~9-10
galaxies over the first 19 clusters in the CLASH program. A systematic search
yields three z~9-10 candidates. While we have already reported the most robust
of these candidates, MACS1149-JD, two additional z~9 candidates are also found
and have H_{160}-band magnitudes of ~26.2-26.9. A careful assessment of various
sources of contamination suggests <~1 contaminants for our z~9-10 selection. To
determine the implications of these search results for the LF and SFR density
at z~9, we introduce a new differential approach to deriving these quantities
in lensing fields. Our procedure is to derive the evolution by comparing the
number of z~9-10 galaxy candidates found in CLASH with the number of galaxies
in a slightly lower redshift sample (after correcting for the differences in
selection volumes), here taken to be z~8. This procedure takes advantage of the
fact that the relative volumes available for the z~8 and z~9-10 selections
behind lensing clusters are not greatly dependent on the details of the lensing
models. We find that the normalization of the UV LF at z~9 is just
0.28_{-0.20}^{+0.39}\times that at z~8, ~1.4_{-0.8}^{+3.0}x lower than
extrapolating z~4-8 LF results. While consistent with the evolution in the UV
LF seen at z~4-8, these results marginally favor a more rapid evolution at z>8.
Compared to similar evolutionary findings from the HUDF, our result is less
insensitive to large-scale structure uncertainties, given our many independent
sightlines on the high-redshift universe.Comment: 22 pages, 11 figures, 5 tables, accepted for publication in the
Astrophysical Journal, updated to include the much deeper Spitzer/IRAC
observations over our three z~9-10 candidate
CLASH: Photometric redshifts with 16 HST bands in galaxy cluster fields
The Cluster Lensing And Supernovae survey with Hubble (CLASH) is an Hubble
Space Telescope (HST) Multi-Cycle Treasury program observing 25 massive galaxy
clusters. CLASH observations are carried out in 16 bands from UV to NIR to
derive accurate and reliable estimates of photometric redshifts. We present the
CLASH photometric redshifts and study the photometric redshift accuracy of the
arcs in more detail for the case of MACS1206.2-0847. We use the publicly
available Le Phare and BPZ photometric redshift codes on 17 CLASH galaxy
clusters. Using Le Phare code for objects with StoN>=10, we reach a precision
of 3%(1+z) for the strong lensing arcs, which is reduced to 2.4%(1+z) after
removing outliers. For galaxies in the cluster field the corresponding values
are 4%(1+z) and 3%(1+z). Using mock galaxy catalogues, we show that 3%(1+z)
precision is what one would expect from the CLASH photometry when taking into
account extinction from dust, emission lines and the finite range of SEDs
included in the photo-z template library. We study photo-z results for
different aperture photometry and find that the SExtractor isophotal photometry
works best. Le Phare and BPZ give similar photo-z results for the strong
lensing arcs as well as galaxies of the cluster field. Results are improved
when optimizing the photometric aperture shape showing an optimal aperture size
around 1" radius giving results which are equivalent to isophotal photometry.
Tailored photometry of the arcs improve the photo-z results.Comment: Accepted in A&A on nov 201
Tropospheric O 3 moderates responses of temperate hardwood forests to elevated CO 2 : a synthesis of molecular to ecosystem results from the Aspen FACE project
1. The impacts of elevated atmospheric CO 2 and/or O 3 have been examined over 4 years using an open-air exposure system in an aggrading northern temperate forest containing two different functional groups (the indeterminate, pioneer, O 3 -sensitive species Trembling Aspen, Populus tremuloides and Paper Birch, Betula papyrifera , and the determinate, late successional, O 3 -tolerant species Sugar Maple, Acer saccharum ). 2. The responses to these interacting greenhouse gases have been remarkably consistent in pure Aspen stands and in mixed Aspen/Birch and Aspen/Maple stands, from leaf to ecosystem level, for O 3 -tolerant as well as O 3 -sensitive genotypes and across various trophic levels. These two gases act in opposing ways, and even at low concentrations (1·5 × ambient, with ambient averaging 34–36 nL L −1 during the summer daylight hours), O 3 offsets or moderates the responses induced by elevated CO 2 . 3. After 3 years of exposure to 560 µmol mol −1 CO 2 , the above-ground volume of Aspen stands was 40% above those grown at ambient CO 2 , and there was no indication of a diminishing growth trend. In contrast, O 3 at 1·5 × ambient completely offset the growth enhancement by CO 2 , both for O 3 -sensitive and O 3 -tolerant clones. Implications of this finding for carbon sequestration, plantations to reduce excess CO 2 , and global models of forest productivity and climate change are presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72125/1/j.1365-2435.2003.00733.x.pd
CLASH: New Multiple-Images Constraining the Inner Mass Profile of MACS J1206.2-0847
We present a strong-lensing analysis of the galaxy cluster MACS J1206.2-0847
(=0.44) using UV, Optical, and IR, HST/ACS/WFC3 data taken as part of the
CLASH multi-cycle treasury program, with VLT/VIMOS spectroscopy for some of the
multiply-lensed arcs. The CLASH observations, combined with our mass-model,
allow us to identify 47 new multiply-lensed images of 12 distant sources. These
images, along with the previously known arc, span the redshift range 1\la
z\la5.5, and thus enable us to derive a detailed mass distribution and to
accurately constrain, for the first time, the inner mass-profile of this
cluster. We find an inner profile slope of (in the range [1\arcsec, 53\arcsec], or 5\la r \la300 kpc), as
commonly found for relaxed and well-concentrated clusters. Using the many
systems uncovered here we derive credible critical curves and Einstein radii
for different source redshifts. For a source at , the critical
curve encloses a large area with an effective Einstein radius of
\theta_{E}=28\pm3\arcsec, and a projected mass of . From the current understanding of structure formation in
concordance cosmology, these values are relatively high for clusters at
, so that detailed studies of the inner mass distribution of clusters
such as MACS J1206.2-0847 can provide stringent tests of the CDM
paradigm.Comment: 7 pages, 1 table, 4 figures; submitted to ApJ Letters; V3: minor
correction
Pediatricians and nutritionists knowledge about treatment of cow milk allergy in infants
OBJECTIVE: Evaluate the knowledge of pediatricians and nutritionists regarding the exclusion diet of cow milk and derivates, with emphasis on questions related to the nutrition of children submitted to such diet. METHODS: Cross-sectional study that enrolled pediatricians (n=53) and nutritionists (n=29) from public hospitals in São Paulo, Brazil, during 2005. Data was collected through self-administered questionnaires. RESULTS: The age of the professionals varied from 21 to 50 years old. Regarding professional experience, 41.2% were graduated for less than five years and 91.6% had a specialization course, masters and/or PhD degree. The vast majority of professionals (97.5%) confirmed that they regularly evaluated the diet of children that needed exclusion of cow milk. However, only 48% of the professionals conducted a more detailed evaluation of the diet, including calculations of food ingestion. Only 38.7% of the professionals compared child s food ingestion with some recommended pattern. Recommendations for daily ingestion of calcium by children up to the age of 36 months were properly mentioned by 22% of the pediatricians and 60.7% of the nutritionists (p=0.001). Inadequate cow milk substitute products were recommended by 66% of the pediatricians and by 48.3% of the nutritionists. Regarding labels of industrialized products, 81.6% of the pediatricians and 96.4% of the nutritionists advised the parents to look for all terms that could indicate the presence of cow milk protein. CONCLUSIONS: Pediatricians and nutritionists made conceptual errors in their main recommendations regarding the treatment of cow milk protein allergy.OBJETIVO: Avaliar o conhecimento de pediatras e nutricionistas sobre a dieta de exclusão do leite de vaca e seus derivados, com ênfase em questões relacionadas à nutrição da criança. MÉTODOS: Estudo transversal descritivo, do qual participaram pediatras (n=53) e nutricionistas (n=29), vinculados a hospitais públicos do Município de São Paulo, no ano de 2005. Os dados foram coletados por questionário auto-administrado. RESULTADOS: A idade dos profissionais variou de 21 a 50 anos. Quanto ao tempo de graduação, 41,2% eram formados a menos de cinco anos e 91,6% possuíam especialização, mestrado e/ou doutorado. A maioria (97,5%) afirmou avaliar a dieta de crianças submetidas à exclusão do leite de vaca, entretanto, somente 48% o faziam de forma mais detalhadas, incluindo o cálculo da ingestão alimentar. Apenas 38,7% comparam a ingestão alimentar da criança com algum padrão de recomendação. A recomendação diária da ingestão de cálcio para crianças com até 36 meses foi corretamente assinalada por 22% dos pediatras e 60,7% dos nutricionistas (p=0,001). Produtos não adequados como substitutos do leite de vaca seriam recomendados por 66% dos pediatras e 48,3% dos nutricionistas. Com relação à leitura de rótulos de produtos industrializados, 81,6% dos pediatras e 96,4% dos nutricionistas orientam os pais a ler todos os termos que indicam a presença das proteínas do leite de vaca. CONCLUSÕES: Os pediatras e nutricionista demonstraram erro conceitual no que se refere às principais recomendações terapêuticas na alergia às proteínas do leite de vaca.Universidade Federal de São Paulo (UNIFESP)UNIFESPUNIFESPSciEL
Constraining New Physics with a Positive or Negative Signal of Neutrino-less Double Beta Decay
We investigate numerically how accurately one could constrain the strengths
of different short-range contributions to neutrino-less double beta decay in
effective field theory. Depending on the outcome of near-future experiments
yielding information on the neutrino masses, the corresponding bounds or
estimates can be stronger or weaker. A particularly interesting case, resulting
in strong bounds, would be a positive signal of neutrino-less double beta decay
that is consistent with complementary information from neutrino oscillation
experiments, kinematical determinations of the neutrino mass, and measurements
of the sum of light neutrino masses from cosmological observations. The keys to
more robust bounds are improvements of the knowledge of the nuclear physics
involved and a better experimental accuracy.Comment: 23 pages, 3 figures. Minor changes. Matches version published in JHE
The Cluster Lensing and Supernova Survey with Hubble (CLASH): Strong Lensing Analysis of Abell 383 from 16-Band HST WFC3/ACS Imaging
We examine the inner mass distribution of the relaxed galaxy cluster Abell
383 in deep 16-band HST/ACS+WFC3 imaging taken as part of the CLASH multi-cycle
treasury program. Our program is designed to study the dark matter distribution
in 25 massive clusters, and balances depth with a wide wavelength coverage to
better identify lensed systems and generate precise photometric redshifts. This
information together with the predictive strength of our strong-lensing
analysis method identifies 13 new multiply-lensed images and candidates, so
that a total of 27 multiple-images of 9 systems are used to tightly constrain
the inner mass profile, (r<160 kpc).
We find consistency with the standard distance-redshift relation for the full
range spanned by the lensed images, 1.01<z<6.03, with the higher redshift
sources deflected through larger angles as expected. The inner mass profile
derived here is consistent with the results of our independent weak-lensing
analysis of wide-field Subaru images, with good agreement in the region of
overlap. The overall mass profile is well fitted by an NFW profile with
M_{vir}=(5.37^{+0.70}_{-0.63}\pm 0.26) x 10^{14}M_{\odot}/h and a relatively
high concentration, c_{vir}=8.77^{+0.44}_{-0.42}\pm 0.23, which lies above the
standard c-M relation similar to other well-studied clusters. The critical
radius of Abell 383 is modest by the standards of other lensing clusters,
r_{E}\simeq16\pm2\arcsec (for z_s=2.55), so the relatively large number of
lensed images uncovered here with precise photometric redshifts validates our
imaging strategy for the CLASH survey. In total we aim to provide similarly
high-quality lensing data for 25 clusters, 20 of which are X-ray selected
relaxed clusters, enabling a precise determination of the representative mass
profile free from lensing bias. (ABRIDGED)Comment: 15 pages, 14 figures, 2 tabels; V3 matches the submitted version
later published in Ap
First trimester placental endothelial cells from pregnancies with abnormal uterine artery Doppler are more sensitive to apoptotic stimuli.
Failure of the placental capillary network to develop normally is associated with early onset fetal growth restriction (FGR) and pre-eclampsia (PE). Although the symptoms are observed at term, the problem begins in the first trimester. However, investigations at this clinically relevant time are hindered by difficulties in identifying earlystage pregnancies that are at risk of developing FGR/PE. Using uterine artery Doppler ultrasound in the first trimester as a proxy measure of poor placentation, we have identified pregnancies at increased risk of developing early onset FGR/PE. Placental endothelial cells (PEC) isolated from pregnancies at increased risk of developing FGR/PE grew more slowly and their basal rate of apoptosis was significantly higher than that seen in the normal group. The pro-apoptotic stimulus, TNFα, induced apoptosis in cells from both groups but this was significantly greater in the high risk group. TNF receptor expression was unaffected. Inhibition of nitric oxide (NO) production significantly increased the sensitivity of cells from the normal pregnancies to TNFα but not in the high risk group establishing a functional role for NO in this system. In conclusion, first trimester PEC from pregnancies at increased risk of developing early onset FGR/PE were inherently more sensitive to apoptotic stimuli and this was functionally linked to the synthesis of NO. This may contribute to the poor placental vascular development seen in on going pregnancies
Some Aspects of Multifractal analysis
The aim of this survey is to present some aspects of multifractal analysis
around the recently developed subject of multiple ergodic averages. Related
topics include dimensions of measures, oriented walks, Riesz products etc
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