13,787 research outputs found
On the Presence of Thermal SZ Induced Signal in the First Year WMAP Temperature Maps
Using available optical and X-ray catalogues of clusters and superclusters of
galaxies, we build templates of tSZ emission as they should be detected by the
WMAP experiment. We compute the cross-correlation of our templates with WMAP
temperature maps, and interpret our results separately for clusters and for
superclusters of galaxies. For clusters of galaxies, we claim 2-5
detections in our templates built from BCS Ebeling et al. (1998), NORAS
(Boehringer et al. 2000) and de Grandi et al. (1999) catalogues. In these
templates, the typical cluster temperature decrements in WMAP maps are around
15-35 K in the RJ range (no beam deconvolution applied). Several tests
probing the possible influence of foregrounds in our analyses demonstrate that
our results are robust against galactic contamination. On supercluster scales,
we detect a diffuse component in the V & W WMAP bands which cannot be generated
by superclusters in our catalogues (Einasto et al. 1994, 1997), and which is
not present in the clean map of Tegmark, de Oliveira-Costa & Hamilton (2003).
Using this clean map, our analyses yield, for Einasto's supercluster
catalogues, the following upper limit for the comptonization parameter
associated to supercluster scales: y_{SC} < 2.18 \time s 10^{-8} at the 95%
confidence limit.Comment: MNRAS accepted. New section and minor changes include
Limits on Hot Intracluster Gas Contributions to the Tenerife Temperature Anisotropy Map
We limit the contribution of the hot intracluster gas, by means of the
Sunyaev-Zel'dovich effect, to the temperature anisotropies measured by the
Tenerife experiment. The data is cross-correlated with maps generated from the
ACO cluster catalogue, the ROSAT PSPC catalogue of clusters of galaxies, a
catalogue of superclusters and the HEAO 1 A-1 map of X-ray sources. There is no
evidence of contamination by such sources at an rms level of K at
99% confidence level at angular resolution. We place an upper limit on
the mean Comptonization parameter of at the same
level of confidence. These limits are slightly more restrictive than those
previously found by a similar analysis on the COBE/DMR data and indicate that
most of the signal measured by Tenerife is cosmological.Comment: To be published in ApJ (main journal
Fourier Mukai Transforms for Gorenstein Schemes
We extend to singular schemes with Gorenstein singularities or fibered in
schemes of that kind Bondal and Orlov's criterion for an integral functor to be
fully faithful. We also contemplate a criterion for equivalence. We offer a
proof that is new even if we restrict to the smooth case. In addition, we prove
that for locally projective Gorenstein morphisms, a relative integral functor
is fully faithful if and only if its restriction to each fibre also is it.
These results imply the invertibility of the usual relative Fourier-Mukai
transform for an elliptic fibration as a direct corollary.Comment: Final version. To appear in Advances in Mathematic
Season of the year influences infection rates following total hip arthroplasty
To research the influence of season of the year on periprosthetic joint infections. METHODS We conducted a retrospective review of the entire Medicare files from 2005 to 2014. Seasons were classified as spring, summer, fall or winter. Regional variations were accounted for by dividing patients into four geographic regions as per the United States Census Bureau (Northeast, Midwest, West and South). Acute postoperative infection and deep periprosthetic infections within 90 d after surgery were tracked. RESULTS In all regions, winter had the highest incidence of periprosthetic infections (mean 0.98%, SD 0.1%) and was significantly higher than other seasons in the Midwest, South and West (P \u3c 0.05 for all) but not the Northeast (P = 0.358). Acute postoperative infection rates were more frequent in the summer and were significantly affected by season of the year in the West. CONCLUSION Season of the year is a risk factor for periprosthetic joint infection following total hip arthroplasty (THA). Understanding the influence of season on outcomes following THA is essential when risk-stratifying patients to optimize outcomes and reduce episode of care costs. © The Author(s) 2017
The Pristine survey II: a sample of bright stars observed with FEROS
Extremely metal-poor (EMP) stars are old objects formed in the first Gyr of
the Universe. They are rare and, to select them, the most successful strategy
has been to build on large and low-resolution spectroscopic surveys. The
combination of narrow- and broad band photometry provides a powerful and
cheaper alternative to select metal-poor stars. The on-going Pristine Survey is
adopting this strategy, conducting photometry with the CFHT MegaCam wide field
imager and a narrow-band filter centred at 395.2 nm on the CaII-H and -K lines.
In this paper we present the results of the spectroscopic follow-up conducted
on a sample of 26 stars at the bright end of the magnitude range of the Survey
(g<=15), using FEROS at the MPG/ESO 2.2 m telescope. From our chemical
investigation on the sample, we conclude that this magnitude range is too
bright to use the SDSS gri bands, which are typically saturated. Instead the
Pristine photometry can be usefully combined with the APASS gri photometry to
provide reliable metallicity estimates.Comment: AN accepte
A novel scanning lens instrument for evaluating Fresnel lens performance: equipment development and initial results
A system dedicated to the optical transmittance characterization of Fresnel lenses has been developed at
NREL, in collaboration with the UPM. The system quantifies the optical efficiency of the lens by generating a performance map. The shape of the focused spot may also be analyzed to understand change in the lens performance. The primary instrument components (lasers and CCD detector) have been characterized to confirm their capability for performing optical transmittance measurements. Measurements performed on SoG and PMMA lenses subject to a variety of indoor conditions (e.g., UV and damp heat) identified differences in the optical efficiency of the evaluated
lenses, demonstrating the ability of the Scanning Lens Instrument (SLI) to distinguish between the aged lenses
ISO spectroscopy of compact HII regions in the Galaxy. II Ionization and elemental abundances
Based on the ISO spectral catalogue of compact HII regions by Peeters et al.
(2001), we present a first analysis of the hydrogen recombination and atomic
fine-structure lines originated in the ionized gas. The sample consists of 34
HII regions located at galactocentric distances between Rgal = 0 and 15 kpc.
The SWS HI recombination lines between 2 and 8 mum are used to estimate the
extinction law at these wavelengths for 14 HII regions. An extinction in the K
band between 0 and 3 mag. has been derived. The fine-structure lines of
N, O, Ne, S and Ar are detected in most of the sources. Most of these elements
are observed in two different ionization stages probing a range in ionization
potential up to 41 eV. The ISO data, by itself or combined with radio data
taken from the literature, is used to derive the elemental abundances relative
to hydrogen. The present data thus allow us to describe for each source its
elemental abundance, its state of ionization and to constrain the properties of
the ionizing star(s).Comment: Accepted in Astronomy and Astrophysics, 22 pages, 20 figures, 9
table
Walls talk: Microbial biogeography of homes spanning urbanization.
Westernization has propelled changes in urbanization and architecture, altering our exposure to the outdoor environment from that experienced during most of human evolution. These changes might affect the developmental exposure of infants to bacteria, immune development, and human microbiome diversity. Contemporary urban humans spend most of their time indoors, and little is known about the microbes associated with different designs of the built environment and their interaction with the human immune system. This study addresses the associations between architectural design and the microbial biogeography of households across a gradient of urbanization in South America. Urbanization was associated with households' increased isolation from outdoor environments, with additional indoor space isolation by walls. Microbes from house walls and floors segregate by location, and urban indoor walls contain human bacterial markers of space use. Urbanized spaces uniquely increase the content of human-associated microbes-which could increase transmission of potential pathogens-and decrease exposure to the environmental microbes with which humans have coevolved
Dynamic earthquake triggering response tracks evolving unrest at Sierra Negra volcano, Galápagos Islands
The propensity for dynamic earthquake triggering is thought to depend on the local stress state and amplitude of
the stress perturbation. However, the nature of this dependency has not been confirmed within a single crustal
volume. Here, we show that at Sierra Negra volcano, Galápagos Islands, the intensity of dynamically triggered
earthquakes increased as inflation of a magma reservoir elevated the stress state. The perturbation of short-term
seismicity within teleseismic surface waves also increased with peak dynamic strain. Following rapid coeruptive
subsidence and reduction in stress and background seismicity rates, equivalent dynamic strains no longer triggered
detectable seismicity. These findings offer direct constraints on the primary controls on dynamic triggering
and suggest that the response to dynamic stresses may help constrain the evolution of volcanic unrest
- …