9,368 research outputs found
An analysis of the shapes of interstellar extinction curves. VII Milky Way spectrophotometric optical-through-ultraviolet extinction and its R-dependence
We produce a set of 72 NIR-through-UV extinction curves by combining new Hubble Space Telescope/STIS optical spectrophotometry with existing International Ultraviolet Explorer spectrophotometry (yielding gapless coverage from 1150 to 10000 ?) and NIR photometry. These curves are used to determine a new, internally consistent NIR-through-UV Milky Way mean curve and to characterize how the shapes of the extinction curves depend on R(V). We emphasize that while this dependence captures much of the curve variability, considerable variation remains that is independent of R(V). We use the optical spectrophotometry to verify the presence of structure at intermediate wavelength scales in the curves. The fact that the optical-through-UV portions of the curves are sampled at relatively high resolution makes them very useful for determining how extinction affects different broadband systems, and we provide several examples. Finally, we compare our results to previous investigations
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The effect of weld residual stresses and their re-distribution with crack growth during fatigue under constant amplitude loading
In this work the evolution of the residual stresses in a MIG-welded 2024-T3 aluminium alloy M(T) specimen during in situ fatigue crack growth at constant load amplitude has been measured with neutron diffraction. The plastic relaxation and plasticity-induced residual stresses associated with the fatigue loading were found to be small compared with the stresses arising due to elastic re-distribution of the initial residual stress field. The elastic re-distribution was modelled with a finite element simulation and a good correlation between the experimentally-determined and the modelled stresses was found. A significant mean stress effect on the fatigue crack growth rate was seen and this was also accurately predicted using the measured initial residual stresses
New Ultraviolet Extinction Curves for Interstellar Dust in M31
New low-resolution UV spectra of a sample of reddened OB stars in M31 were
obtained with HST/STIS to study the wavelength dependence of interstellar
extinction and the nature of the underlying dust grain populations. Extinction
curves were constructed for four reddened sightlines in M31 paired with closely
matching stellar atmosphere models. The new curves have a much higher S/N than
previous studies. Direct measurements of N(H I) were made using the Ly
absorption lines enabling gas-to-dust ratios to be calculated. The sightlines
have a range in galactocentric distance of 5 to 14 kpc and represent dust from
regions of different metallicities and gas-to-dust ratios. The metallicities
sampled range from Solar to 1.5 Solar. The measured curves show similarity to
those seen in the Milky Way and the Large Magellanic Cloud. The Maximum Entropy
Method was used to investigate the dust composition and size distribution for
the sightlines observed in this program finding that the extinction curves can
be produced with the available carbon and silicon abundances if the metallicity
is super-Solar.Comment: ApJ, in press, 9 pages, 5 figure
Relaxing to a three dimensional brane junction
We suggest a mechanism which leads to 3+1 space-time dimensions. The Universe
assumed to have nine spatial dimensions is regarded as a special nonlinear
oscillatory system -- a kind of Einstein solid. There are p-brane solutions
which manifest as phase oscillations separating different phase states. The
presence of interactions allows for bifurcations of higher dimensional spaces
to lower dimensional ones in the form of brane junctions. We argue this is a
natural way to select lower dimensions.Comment: RevTex, 5 pages; version to appear in Europhys. Let
A review of agriculture on the Esperance Downs
Esperance is approaching a period of rapid development based on the results of research at Esperance Downs Research Station and on farmers\u27 properties in the area.
This article reviews the soils, vegetation, climate, agricultural development and development costs of the area
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Evaluating New Interactions in Healthcare: Challenges and Approaches
New technologies for supporting the provision of healthcare are increasingly pervasive. While healthcare computing previously referred to a desktop computer within the consulting room, we are now seeing an ever broader range of software, hardware and settings. This workshop is concerned with how to conduct evaluations which allow assessment of the overall impact of technology. The workshop will explore challenges and approaches for evaluating new interactions in healthcare. In this paper we outline the goals for this workshop and summarize the issues and questions it intends to explore
After the Standard Model: New Resonances at the LHC
Experiments will soon start taking data at CERN's Large Hadron Collider (LHC)
with high expectations for discovery of new physics phenomena. Indeed, the
LHC's unprecedented center-of-mass energy will allow the experiments to probe
an energy regime where the standard model is known to break down. In this
article, the experiments' capability to observe new resonances in various
channels is reviewed.Comment: Preprint version of a Brief Review for Modern Physics Letters A.
Changes w.r.t. the fully corrected version are smal
Protocol for the United Kingdom Rotator Cuff Study (UKUFF) : a randomised controlled trial of open and arthroscopic rotator cuff repair
This project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02). J. L. Rees has received a grant from Oxford University which is related to this paper. J. Dawson reports that Oxford University has received a grant from HTA which is related to this paper, as well as a study grant.Peer reviewedPublisher PD
Sequestering CP Violation and GIM-Violation with Warped Extra Dimensions
We propose a model of spontaneous CP violation to address the strong CP
problem in warped extra dimensions that relies on sequestering flavor and CP
violation. We assume that brane-localized Higgs Yukawa interactions respect a
U(3) flavor symmetry that is broken only by bulk fermion mass and Yukawa terms.
All CP violation arises from the vev of a CP-odd scalar field localized in the
bulk. To suppress radiative corrections to theta-bar, the doublet quarks in
this model are localized on the IR brane. We calculate constraints from
flavor-changing neutral currents (FCNCs), precision electroweak measurements,
CKM unitarity, and the electric dipole moments in this model and predict
theta-bar to be at least about 10^-12.Comment: 38 page
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