165 research outputs found
Gender Patterns in Vietnam's Child Mortality
We analyze child mortality in Vietnam focusing on gender aspects. Contrary to several other countries in the region, mortality rates for boys are substantially larger than for girls. A large rural-urban mortality difference exists, but much more so for boys than for girls. A higher education level of the mother reduces mortality risk, but the effect is stronger for girls than for boys.child mortality, gender differences, hazard rate, frailty model
Emission of photon echoes in a strongly scattering medium
We observe the two- and three-pulse photon echo emission from a scattering
powder, obtained by grinding a Pr:YSiO rare earth doped single
crystal. We show that the collective emission is coherently constructed over
several grains. A well defined atomic coherence can therefore be created
between randomly placed particles. Observation of photon echo on powders as
opposed to bulk materials opens the way to faster material development. More
generally, time-domain resonant four-wave mixing offers an attractive approach
to investigate coherent propagation in scattering media
The Far-Infrared--Radio Correlation at High Redshifts: Physical Considerations and Prospects for the Square Kilometer Array
(Abridged) I present a predictive analysis for the behavior of the FIR--radio
correlation as a function of redshift in light of the deep radio continuum
surveys which may become possible using the SKA. To keep a fixed ratio between
the FIR and predominantly non-thermal radio continuum emission of a normal
star-forming galaxy requires a nearly constant ratio between galaxy magnetic
field and radiation field energy densities. While the additional term of IC
losses off of the cosmic microwave background (CMB) is negligible in the local
Universe, the rapid increase in the strength of the CMB energy density (i.e.
suggests that evolution in the FIR-radio correlation should
occur with infrared (IR; 8-1000 \micron)/radio ratios increasing with
redshift. At present, observations do not show such a trend with redshift;
radio-quiet QSOs appear to lie on the local FIR-radio correlation
while a sample of and SMGs exhibit ratios that are a
factor of 2.5 {\it below} the canonical value. I also derive a 5
point-source sensitivity goal of 20 nJy (i.e. nJy) requiring that the SKA specified be m K; achieving this sensitivity should enable the detection
of galaxies forming stars at a rate of \ga25 M_{\sun} {\rm yr}^{-1}, at all
redshifts if present. By taking advantage of the fact that the non-thermal
component of a galaxy's radio continuum emission will be quickly suppressed by
IC losses off of the CMB, leaving only the thermal (free-free) component, I
argue that deep radio continuum surveys at frequencies \ga10 GHz may prove to
be the best probe for characterizing the high- star formation history of the
Universe unbiased by dust.Comment: 16 pages, 8 figures, accepted for publication in Ap
Innate immunity, assessed by plasma NO measurements, is not suppressed during the incubation fast in eiders
Immunity is hypothesized to share limited resources with other physiological
functions and may mediate life history trade-offs, for example between
reproduction and survival. However, vertebrate immune defense is a complex
system that consists of three components. To date, no study has assessed all of
these components for the same animal model and within a given situation.
Previous studies have determined that the acquired immunity of common eiders
(Somateria mollissima) is suppressed during incubation. The present paper aims
to assess the innate immune response in fasting eiders in relation to their
initial body condition. Innate immunity was assessed by measuring plasma nitric
oxide (NO) levels, prior to and after injection of lipopolysaccharides (LPS), a
method which is easily applicable to many wild animals. Body condition index
and corticosterone levels were subsequently determined as indicators of body
condition and stress level prior to LPS injection. The innate immune response
in eiders did not vary significantly throughout the incubation period. The
innate immune response of eiders did not vary significantly in relation to
their initial body condition but decreased significantly when corticosterone
levels increased. However, NO levels after LPS injection were significantly and
positively related to initial body condition, while there was a significant
negative relationship with plasma corticosterone levels. Our study suggests
that female eiders preserve an effective innate immune response during
incubation and this response might be partially determined by the initial body
condition
Cross-correlating Planck tSZ with RCSLenS weak lensing: implications for cosmology and AGN feedback
We present measurements of the spatial mapping between (hot) baryons and the total matter in the Universe, via the cross-correlation between the thermal Sunyaev–Zeldovich (tSZ)map from Planck and the weak gravitational lensing maps from theRed Cluster Sequence Lensing Survey (RCSLenS). The cross-correlations are performed on the map level where all the sources (including diffuse intergalactic gas) contribute to the signal. We consider two configurationspace correlation function estimators, ξ y–κ and ξ y–γt , and a Fourier-space estimator, Cy–κ , in our analysis. We detect a significant correlation out to 3◦ of angular separation on the sky. Based on statistical noise only, we can report 13σ and 17σ detections of the cross-correlation using the configuration-space y–κ and y–γ t estimators, respectively. Including a heuristic estimate of the sampling variance yields a detection significance of 7σ and 8σ, respectively. A similar level of detection is obtained from the Fourier-space estimator, Cy–κ . As each estimator probes different dynamical ranges, their combination improves the significance of the detection. We compare our measurements with predictions from the cosmo-OverWhelmingly Large Simulations suite of cosmological hydrodynamical simulations, where different galactic feedback models are implemented. We find that a model with considerable active galactic nuclei (AGN) feedback that removes large quantities of hot gas from galaxy groups and Wilkinson Microwave Anisotropy Probe 7-yr best-fitting cosmological parameters provides the bestmatch to the measurements. All baryonic models in the context of a Planck cosmology overpredict the observed signal. Similar cosmological conclusions are drawn when we employ a halo model with the observed ‘universal’ pressure profile
Building galaxies by accretion and in-situ star formation
We examine galaxy formation in a cosmological AMR simulation, which includes
two high resolution boxes, one centered on a 3 \times 10^14 M\odot cluster, and
one centered on a void. We examine the evolution of 611 massive (M\ast >
10^10M\odot) galaxies. We find that the fraction of the final stellar mass
which is accreted from other galaxies is between 15 and 40% and increases with
stellar mass. The accreted fraction does not depend strongly on environment at
a given stellar mass, but the galaxies in groups and cluster environments are
older and underwent mergers earlier than galaxies in lower density
environments. On average, the accreted stars are ~2.5 Gyrs older, and ~0.15 dex
more metal poor than the stars formed in-situ. Accreted stellar material
typically lies on the outskirts of galaxies; the average half-light radius of
the accreted stars is 2.6 times larger than that of the in-situ stars. This
leads to radial gradients in age and metallicity for massive galaxies, in
qualitative agreement with observations. Massive galaxies grow by mergers at a
rate of approximately 2.6% per Gyr. These mergers have a median (mass-weighted)
mass ratio less than 0.26 \pm 0.21, with an absolute lower limit of 0.20, for
galaxies with M\ast ~ 10^12 M\odot. This suggests that major mergers do not
dominate in the accretion history of massive galaxies. All of these results
agree qualitatively with results from SPH simulations by Oser et al. (2010,
2012).Comment: 18 pages, 12 figures, submitted to MNRA
A Genetic Deconstruction of Neurocognitive Traits in Schizophrenia and Bipolar Disorder
Background: Impairments in cognitive functions are common in patients suffering from psychiatric disorders, such as schizophrenia and bipolar disorder. Cognitive traits have been proposed as useful for understanding the biological and genetic mechanisms implicated in cognitive function in healthy individuals and in the dysfunction observed in psychiatric disorders. Methods: Sets of genes associated with a range of cognitive functions often impaired in schizophrenia and bipolar disorder were generated from a genome-wide association study (GWAS) on a sample comprising 670 healthy Norwegian adults who were phenotyped for a broad battery of cognitive tests. These gene sets were then tested for enrichment of association in GWASs of schizophrenia and bipolar disorder. The GWAS data was derived from three independent single-centre schizophrenia samples, three independent single-centre bipolar disorder samples, and the multi-centre schizophrenia and bipolar disorder samples from the Psychiatric Genomics Consortium. Results: The strongest enrichments were observed for visuospatial attention and verbal abilities sets in bipolar disorder. Delayed verbal memory was also enriched in one sample of bipolar disorder. For schizophrenia, the strongest evidence of enrichment was observed for the sets of genes associated with performance in a colour-word interference test and for sets associated with memory learning slope. Conclusions: Our results are consistent with the increasing evidence that cognitive functions share genetic factors with schizophrenia and bipolar disorder. Our data provides evidence that genetic studies using polygenic and pleiotropic models can be used to link specific cognitive functions with psychiatric disorders
Galaxies at a redshift of similar to 0.5 around three closely spaced quasar sightlines
We examine the relationship between galaxies and the intergalactic medium at z < 1 using a group of three closely spaced background quasi-stellar objects (QSOs) with zem ≈ 1 observed with the Hubble Space Telescope. Using a new grouping algorithm, we identify groups of galaxies and absorbers across the three QSO sightlines that may be physically linked. There is an excess number of such groups compared to the number we expect from a random distribution of absorbers at a confidence level of 99.9 per cent. The same search is performed with mock spectra generated using a hydrodynamical simulation, and we find that the vast majority of such groups arise in dense regions of the simulation.We find that atz<0.5, groups in the simulation generally trace the large-scale filamentary structure as seen in the projected 2D distribution of the HI column density in an ∼30 h
−1 Mpc region. We discover a probable sub-damped Lyman α system at z = 0.557 showing strong, low-ionization metal absorption lines. Previous analyses of absorption across the three sightlines attributed these metal lines to HI. We show that even when the new line identifications are taken into account, evidence remains for planar structures with scales of ∼1 Mpc absorbing across the three sightlines. We identify a galaxy at z = 0.2272 with associated metal absorption in two sightlines, each 200 kpc away. By constraining the star formation history of the galaxy, we show that the gas causing this metal absorption may have been enriched and ejected by the galaxy during a burst of star formation 2 Gyr ago
Seasonality of MRSA Infections
Using MRSA isolates submitted to our hospital microbiology laboratory January 2001–March 2010 and the number of our emergency department (ED) visits, quarterly community-associated (CA) and hospital-associated (HA) MRSA infections were modeled using Poisson regressions. For pediatric patients, approximately 1.85x (95% CI 1.45x–2.36x, adj. p<0.0001) as many CA-MRSA infections per ED visit occurred in the second two quarters as occurred in the first two quarters. For adult patients, 1.14x (95% CI 1.01x–1.29x, adj.p = 0.03) as many infections per ED visit occurred in the second two quarters as in the first two quarters. Approximately 2.94x (95% CI 1.39x–6.21x, adj.p = 0.015) as many HA-MRSA infections per hospital admission occurred in the second two quarters as occurred in the first two quarters for pediatric patients. No seasonal variation was observed among adult HA-MRSA infections per hospital admission. We demonstrated seasonality of MRSA infections and provide a summary table of similar observations in other studies
- …