31,974 research outputs found
Improved Time-Domain Accuracy Standards for Model Gravitational Waveforms
Model gravitational waveforms must be accurate enough to be useful for
detection of signals and measurement of their parameters, so appropriate
accuracy standards are needed. Yet these standards should not be unnecessarily
restrictive, making them impractical for the numerical and analytical modelers
to meet. The work of Lindblom, Owen, and Brown [Phys. Rev. D 78, 124020 (2008)]
is extended by deriving new waveform accuracy standards which are significantly
less restrictive while still ensuring the quality needed for gravitational-wave
data analysis. These new standards are formulated as bounds on certain norms of
the time-domain waveform errors, which makes it possible to enforce them in
situations where frequency-domain errors may be difficult or impossible to
estimate reliably. These standards are less restrictive by about a factor of 20
than the previously published time-domain standards for detection, and up to a
factor of 60 for measurement. These new standards should therefore be much
easier to use effectively.Comment: 10 pages, 5 figure
Including the urban heat island in spatial heat health risk assessment strategies: a case study for Birmingham, UK
Background
Heatwaves present a significant health risk and the hazard is likely to escalate with the increased future temperatures presently predicted by climate change models. The impact of heatwaves is often felt strongest in towns and cities where populations are concentrated and where the climate is often unintentionally modified to produce an urban heat island effect; where urban areas can be significantly warmer than surrounding rural areas. The purpose of this interdisciplinary study is to integrate remotely sensed urban heat island data alongside commercial social segmentation data via a spatial risk assessment methodology in order to highlight potential heat health risk areas and build the foundations for a climate change risk assessment. This paper uses the city of Birmingham, UK as a case study area.
Results
When looking at vulnerable sections of the population, the analysis identifies a concentration of "very high" risk areas within the city centre, and a number of pockets of "high risk" areas scattered throughout the conurbation. Further analysis looks at household level data which yields a complicated picture with a considerable range of vulnerabilities at a neighbourhood scale.
Conclusions
The results illustrate that a concentration of "very high" risk people live within the urban heat island, and this should be taken into account by urban planners and city centre environmental managers when considering climate change adaptation strategies or heatwave alert schemes. The methodology has been designed to be transparent and to make use of powerful and readily available datasets so that it can be easily replicated in other urban areas
Proton and neutron electromagnetic form factors and uncertainties
We determine the nucleon electromagnetic form factors and their uncertainties
from world electron scattering data. The analysis incorporates two-photon
exchange corrections, constraints on the low-Q2 and high-Q2 behavior, and
additional uncertainties to account for tensions between different data sets
and uncertainties in radiative corrections.Comment: 9 pages, 7 figures. Published on Phys. Lett.
Constraining the Envelope Structure of L1527 IRS: Infrared Scattered Light Modeling
We model Spitzer Space Telescope observations of the Taurus Class 0 protostar
L1527 IRS (IRAS 04368+2557) to provide constraints on its protostellar envelope
structure. The nearly edge-on inclination of L1527 IRS, coupled with the highly
spatially-resolved near to mid-infrared images of this object and the detailed
IRS spectrum, enable us to constrain the outflow cavity geometry quite well,
reducing uncertainties in the other derived parameters. The mid-infrared
scattered light image shows a bright central source within a dark lane; the
aspect ratio of this dark lane is such that it appears highly unlikely to be a
disk shadow. In modeling this dark lane, we conclude that L1527 IRS is probably
not described by a standard TSC envelope with simple bipolar cavities. We find
it necessary to model the dark lane and central source as a modified inner
envelope structure. This structure may be due either to a complex wind-envelope
interaction or induced by the central binary. To fit the overall SED, we
require the central source to have a large near to mid-infrared excess,
suggesting substantial disk accretion. Our model reproduces the overall
morphology and surface brightness distribution of L1527 IRS fairly well, given
the limitations of using axisymmetric models to fit the non-axisymmetric real
object, and the derived envelope infall rates are in reasonable agreement with
some other investigations. IRAC observations of L1527 IRS taken 12 months apart
show variability in total flux and variability in the opposing bipolar
cavities, suggesting asymmetric variations in accretion. We also provide model
images at high resolution for comparison to future observations with current
ground-based instrumentation and future space-based telescopes.Comment: 50 pages, 14 figures 2 tables, accepted by the Astrophysical Journal.
The manuscript with full resolution figures can be downloaded from
http://astro.lsa.umich.edu/~jjtobin/L1527.pd
GLOBALIZATION, TECHNOLOGICAL ADVANCES, AND OTHER THREATS TO AMERICAN AGRICULTURE: DISCUSSION
International Relations/Trade,
What is Past is Prologue: The International Conference on Harmonization and Lessons Learned from European Drug Regulations Harmonization
Long term outcomes in men screened for abdominal aortic aneurysm : prospective cohort study
PMID: 22563092 [PubMed - indexed for MEDLINE] PMCID: PMC3344734 Free PMC ArticlePeer reviewedPublisher PD
- …