8,093 research outputs found
Deflection resistance indicator
Instrument for nondestructively measuring compression resistance of spray foam used as thermal insulation was developed. Cylindrical indicator has probe with coil spring to provide force and indicating dial. Probe is manually pressed against area to be tested until complete foot area contacts foam surfaces
PSF calibration requirements for dark energy from cosmic shear
The control of systematic effects when measuring galaxy shapes is one of the
main challenges for cosmic shear analyses. In this context, we study the
fundamental limitations on shear accuracy due to the measurement of the Point
Spread Function (PSF) from the finite number of stars. In order to do that, we
translate the accuracy required for cosmological parameter estimation to the
minimum number of stars over which the PSF must be calibrated. We first derive
our results analytically in the case of infinitely small pixels (i.e.
infinitely high resolution). Then image simulations are used to validate these
results and investigate the effect of finite pixel size in the case of an
elliptical gaussian PSF. Our results are expressed in terms of the minimum
number of stars required to calibrate the PSF in order to ensure that
systematic errors are smaller than statistical errors when estimating the
cosmological parameters. On scales smaller than the area containing this
minimum number of stars, there is not enough information to model the PSF. In
the case of an elliptical gaussian PSF and in the absence of dithering, 2
pixels per PSF Full Width at Half Maximum (FWHM) implies a 20% increase of the
minimum number of stars compared to the ideal case of infinitely small pixels;
0.9 pixels per PSF FWHM implies a factor 100 increase. In the case of a good
resolution and a typical Signal-to-Noise Ratio distribution of stars, we find
that current surveys need the PSF to be calibrated over a few stars, which may
explain residual systematics on scales smaller than a few arcmins. Future
all-sky cosmic shear surveys require the PSF to be calibrated over a region
containing about 50 stars.Comment: 13 pages, 4 figures, accepted by A&
Investigative decision making: missing people and sexual offences, crossroads to an uncertain future
In recent years detective competence and particularly investigative decision making has been subject to serious criticism and a number of high profile reviews. Concerns around investigative competence do not just focus around decisions made on the ground but police attitudes to certain crimes. This paper examines police decision making in the context of missing people and sexual violence and identifies challenges in the development of investigative competence in the context of police budget cuts and substantial reform
Sources of Streptococcus dysgalactiae in English and Welsh sheep flocks affected by infectious arthritis (joint ill)
Wolf-Rayets in IC10: Probing the Nearest Starburst
IC10 is the nearest starburst galaxy, as revealed both by its Halpha surface
brightness and the large number of Wolf-Rayet stars (WRs) per unit area. The
relative number of known WC- to WN-type WRs has been thought to be unusually
high (~2), unexpected for IC10's metallicity. In this Letter we report the
first results of a new and deeper survey for WRs in IC10. We sucessfully
detected all of the spectroscopically known WRs, and based upon comparisons
with a neighboring control field, estimate that the total number of WRs in IC10
is about 100. We present spectroscopic confirmation of two of our WR
candidates, both of which are of WN type. Our photometric survey predicts that
the actual WC/WN ratio is ~0.3. This makes the WC/WN ratio of IC 10 consistent
with that expected for its metallicity, but greatly increases the already
unusually high number of WRs, resulting in a surface density that is about 20
times higher than in the LMC. If the majority of these candidates are
spectroscopically confirmed, IC10 must have an exceptional population of high
mass stars.Comment: Accepted by ApJL; only minor correction in this versio
Searching for "monogenic diabetes" in dogs using a candidate gene approach
BACKGROUND: Canine diabetes is a common endocrine disorder with an estimated breed-related prevalence ranging from 0.005% to 1.5% in pet dogs. Increased prevalence in some breeds suggests that diabetes in dogs is influenced by genetic factors and similarities between canine and human diabetes phenotypes suggest that the same genes might be associated with disease susceptibility in both species. Between 1-5% of human diabetes cases result from mutations in a single gene, including maturity onset diabetes of the adult (MODY) and neonatal diabetes mellitus (NDM). It is not clear whether monogenic forms of diabetes exist within some dog breeds. Identification of forms of canine monogenic diabetes could help to resolve the heterogeneity of the condition and lead to development of breed-specific genetic tests for diabetes susceptibility. RESULTS: Seventeen dog breeds were screened for single nucleotide polymorphisms (SNPs) in eighteen genes that have been associated with human MODY/NDM. Six SNP associations were found from five genes, with one gene (ZFP57) being associated in two different breeds. CONCLUSIONS: Some of the genes that have been associated with susceptibility to MODY and NDM in humans appear to also be associated with canine diabetes, although the limited number of associations identified in this study indicates canine diabetes is a heterogeneous condition and is most likely to be a polygenic trait in most dog breeds. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2052-6687-1-8) contains supplementary material, which is available to authorized users
The Mass Function of Newly Formed Stars (Review)
The topic of the stellar "original mass function" has a nearly 50 year
history,dating to the publication in 1955 of Salpeter's seminal paper. In this
review I discuss the many more recent results that have emerged on the initial
mass function (IMF), as it is now called, from studies over the last decade of
resolved populations in star forming regions and young open clusters.Comment: 9 pages, 1 figure; to appear in "The Dense Instellar Medium in
Galaxies -- 4'th Cologne-Bonn-Zermatt-Symposium" editted by S. Pfalzner, C.
Kramer, C. Straubmeier and A. Heithausen, Springer-Verlag (2004
Experiencing space–time: the stretched lifeworlds of migrant workers in India
In the relatively rare instances when the spatialities of temporary migrant work, workers’ journeys, and labour-market negotiations have been the subject of scholarly attention, there has been little work that integrates time into the analysis. Building on a case study of low-paid and insecure migrant manual workers in the context of rapid economic growth in India, we examine both material and subjective dimensions of these workers’ spatiotemporal experiences. What does it mean to live life stretched out, multiplyattached to places across national space? What kinds of place attachments emerge for people temporarily sojourning in, rather than moving to, new places to reside and work? Our analysis of the spatiotemporalities of migrant workers’ experiences in India suggests that, over time, this group of workers use their own agency to seek to avoid the experience of humiliation and indignity in employment relations. Like David Harvey, we argue that money needs to be integrated into such analysis, along with space and time. The paper sheds light on processes of exclusion, inequality and diff erentiation, unequal power geometries, and social topographies that contrast with neoliberalist narratives of ‘Indian shining
Intrinsic and extrinsic geometries of a tidally deformed black hole
A description of the event horizon of a perturbed Schwarzschild black hole is
provided in terms of the intrinsic and extrinsic geometries of the null
hypersurface. This description relies on a Gauss-Codazzi theory of null
hypersurfaces embedded in spacetime, which extends the standard theory of
spacelike and timelike hypersurfaces involving the first and second fundamental
forms. We show that the intrinsic geometry of the event horizon is invariant
under a reparameterization of the null generators, and that the extrinsic
geometry depends on the parameterization. Stated differently, we show that
while the extrinsic geometry depends on the choice of gauge, the intrinsic
geometry is gauge invariant. We apply the formalism to solutions to the vacuum
field equations that describe a tidally deformed black hole. In a first
instance we consider a slowly-varying, quadrupolar tidal field imposed on the
black hole, and in a second instance we examine the tide raised during a close
parabolic encounter between the black hole and a small orbiting body.Comment: 27 pages, 4 figure
A Subaru Weak Lensing Survey I: Cluster Candidates and Spectroscopic Verification
We present the results of an ongoing weak lensing survey conducted with the
Subaru telescope whose initial goal is to locate and study the distribution of
shear-selected structures or halos. Using a Suprime-cam imaging survey spanning
21.82 square degree, we present a catalog of 100 candidate halos located from
lensing convergence maps. Our sample is reliably drawn from that subset of our
survey area, (totaling 16.72 square degree) uncontaminated by bright stars and
edge effects and limited at a convergence signal to noise ratio of 3.69. To
validate the sample detailed spectroscopic measures have been made for 26
candidates using the Subaru multi-object spectrograph, FOCAS. All are confirmed
as clusters of galaxies but two arise as the superposition of multiple clusters
viewed along the line of sight. Including data available in the literature and
an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable
redshifts. For one of our survey fields, the XMM LSS (Pierre et al. 2004)
field, we compare our lensing-selected halo catalog with its X-ray equivalent.
Of 15 halos detected in the XMM-LSS field, 10 match with published X-ray
selected clusters and a further 2 are newly-detected and spectroscopically
confirmed in this work. Although three halos have not yet been confirmed, the
high success rate within the XMM-LSS field (12/15) confirms that weak lensing
provides a reliable method for constructing cluster catalogs, irrespective of
the nature of the constituent galaxies or the intracluster medium.Comment: To appear in ApJ, High resolution preprint available at
http://anela.mtk.nao.ac.jp/suprime33/papers/p1.ps.g
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