2,381 research outputs found
Biomedical applications team tasks
The status of the biomedical applications team is discussed along with its activity in applications engineering. Various technology requests are summarized
Planck Observations of M33
We have performed a comprehensive investigation of the global integrated flux
density of M33 from radio to ultraviolet wavelengths, finding that the data
between 100 GHz and 3 THz are accurately described by a single modified
blackbody curve with a dust temperature of = 21.670.30 K
and an effective dust emissivity index of = 1.350.10,
with no indication of an excess of emission at millimeter/sub-millimeter
wavelengths. However, sub-dividing M33 into three radial annuli, we found that
the global emission curve is highly degenerate with the constituent curves
representing the sub-regions of M33. We also found gradients in
and across the disk of M33, with both
quantities decreasing with increasing radius. Comparing the M33 dust emissivity
with that of other Local Group members, we find that M33 resembles the
Magellanic Clouds rather than the larger galaxies, i.e., the Milky Way and M31.
In the Local Group sample, we find a clear correlation between global dust
emissivity and metallicity, with dust emissivity increasing with metallicity. A
major aspect of this analysis is the investigation into the impact of
fluctuations in the Cosmic Microwave Background (CMB) on the integrated flux
density spectrum of M33. We found that failing to account for these CMB
fluctuations would result in a significant over-estimate of
by 5 K and an under-estimate of by 0.4.Comment: Accepted for publication in MNRA
A multi-physics computational model of fuel sloshing effects on aeroelastic behaviour
AbstractA multi-physics computational method is presented to model the effect of internally and externally-carried fuel on aeroelastic behaviour of a pitch–plunge aerofoil model through the transonic regime. The model comprises three strongly coupled solvers: a compressible finite-volume Euler code for the external flow, a two-degree of freedom spring model and a smoothed particle hydrodynamics solver for the fuel. The smoothed particle hydrodynamics technique was selected as this brings the benefit that nonlinear behaviour such as wave breaking and tank wall impacts may be included. Coupling is accomplished using an iterative method with subcycling of the fuel solver to resolve the differing timestep requirements. Results from the fuel-structural system are validated experimentally, and internally and externally-carried fuel is considered using time marching analysis. Results show that the influence of the fuel, ignoring the added mass effect, is to raise the flutter boundary at transonic speeds, but that this effect is less pronounced at lower Mach numbers. The stability boundary crossing is also found to be less abrupt when the effect of fuel is included and limit cycles often appear. An external fuel tank is seen to exhibit a lower stability boundary, while the response shows a beating effect symptomatic of two similar frequency components, potentially due to interaction between vertical and horizontal fuel motion
An examination of the precipitation delivery mechanisms for Dolleman Island, eastern Antarctic Peninsula
Copyright @ 2004 Wiley-BlackwellThe variability of size and source of significant precipitation events were studied at an Antarctic ice core drilling site: Dolleman Island (DI), located on the eastern coast of the Antarctic Peninsula. Significant precipitation events that occur at DI were temporally located in the European Centre for Medium-Range Weather Forecasting (ECMWF) reanalysis data set, ERA-40. The annual and summer precipitation totals from ERA-40 at DI both show significant increases over the reanalysis period. Three-dimensional backwards air parcel trajectories were then run for 5 d using the ECMWF ERA-15 wind fields. Cluster analyses were performed on two sets of these backwards trajectories: all days in the range 1979–1992 (the climatological time-scale) and a subset of days when a significant precipitation event occurred. The principal air mass sources and delivery mechanisms were found to be the Weddell Sea via lee cyclogenesis, the South Atlantic when there was a weak circumpolar trough (CPT) and the South Pacific when the CPT was deep. The occurrence of precipitation bearing air masses arriving via a strong CPT was found to have a significant correlation with the southern annular mode (SAM); however, the arrival of air masses from the same region over the climatological time-scale showed no such correlation. Despite the dominance in both groups of back trajectories of the westerly circulation around Antarctica, some other key patterns were identified. Most notably there was a higher frequency of lee cyclogenesis events in the significant precipitation trajectories compared to the climatological time-scale. There was also a tendency for precipitation trajectories to come from more northerly latitudes, mostly from 50–70°S. The El Niño Southern Oscillation (ENSO) was found to have a strong influence on the mechanism by which the precipitation was delivered; the frequency of occurrence of precipitation from the east (west) of DI increased during El Niño (La Niña) events
Dark Energy Constraints from Galaxy Cluster Peculiar Velocities
Future multifrequency microwave background experiments with arcminute
resolution and micro-Kelvin temperature sensitivity will be able to detect the
kinetic Sunyaev-Zeldovich (kSZ) effect, providing a way to measure radial
peculiar velocities of massive galaxy clusters. We show that cluster peculiar
velocities have the potential to constrain several dark energy parameters. We
compare three velocity statistics (the distribution of radial velocities, the
mean pairwise streaming velocity, and the velocity correlation function) and
analyze the relative merits of these statistics in constraining dark energy
parameters. Of the three statistics, mean pairwise streaming velocity provides
constraints that are least sensitive to velocity errors: the constraints on
parameters degrades only by a factor of two when the random error is increased
from 100 to 500 km/s. We also compare cluster velocities with other dark energy
probes proposed in the Dark Energy Task Force report. For cluster velocity
measurements with realistic priors, the eventual constraints on the dark energy
density, the dark energy equation of state and its evolution are comparable to
constraints from supernovae measurements, and better than cluster counts and
baryon acoustic oscillations; adding velocity to other dark energy probes
improves constraints on the figure of merit by more than a factor of two. For
upcoming Sunyaev-Zeldovich galaxy cluster surveys, even velocity measurements
with errors as large as 1000 km/s will substantially improve the cosmological
constraints compared to using the cluster number density alone.Comment: 25 pages, 10 figures. Results and conclusions unchanged. Minor
changes to match the accepted version in Physical Review
C-Band All-Sky Survey: A First Look at the Galaxy
We present an analysis of the diffuse emission at 5 GHz in the first quadrant
of the Galactic plane using two months of preliminary intensity data taken with
the C-Band All Sky Survey (C-BASS) northern instrument at the Owens Valley
Radio Observatory, California. Combining C-BASS maps with ancillary data to
make temperature-temperature plots we find synchrotron spectral indices of
between 0.408 GHz and 5 GHz and between 1.420 GHz and 5 GHz for ,
. Through the subtraction of a radio recombination
line (RRL) free-free template we determine the synchrotron spectral index in
the Galactic plane () to be between
0.408 GHz and 5 GHz, with a contribution of per cent from free-free
emission at 5\,GHz. These results are consistent with previous low frequency
measurements in the Galactic plane. By including C-BASS data in spectral fits
we demonstrate the presence of anomalous microwave emission (AME) associated
with the HII complexes W43, W44 and W47 near 30 GHz, at 4.4 sigma, 3.1 sigma
and 2.5 sigma respectively. The CORNISH VLA 5 GHz source catalogue rules out
the possibility that the excess emission detected around 30\;GHz may be due to
ultra-compact HII regions. Diffuse AME was also identified at a 4 sigma level
within , between 5
GHz and 22.8 GHz.Comment: 16 pages, 9 figures, submitted to MNRAS, referee's corrections made,
awaiting for final approval for publicatio
The C-Band All-Sky Survey (C-BASS): Constraining diffuse Galactic radio emission in the North Celestial Pole region
The C-Band All-Sky Survey C-BASS is a high-sensitivity all-sky radio survey
at an angular resolution of 45 arcmin and a frequency of 4.7 GHz. We present a
total intensity 4.7 GHz map of the North Celestial Pole (NCP) region of sky,
above declination +80 deg, which is limited by source confusion at a level of
~0.6 mK rms. We apply the template-fitting (cross-correlation) technique to
WMAP and Planck data, using the C-BASS map as the synchrotron template, to
investigate the contribution of diffuse foreground emission at frequencies
~20-40 GHz. We quantify the anomalous microwave emission (AME) that is
correlated with far-infrared dust emission. The AME amplitude does not change
significantly (<10%) when using the higher frequency C-BASS 4.7 GHz template
instead of the traditional Haslam 408 MHz map as a tracer of synchrotron
radiation. We measure template coefficients of and
K per unit when using the Haslam and C-BASS synchrotron templates,
respectively. The AME contributes K rms at 22.8 GHz and accounts
for ~60% of the total foreground emission. Our results suggest that a harder
(flatter spectrum) component of synchrotron emission is not dominant at
frequencies >5 GHz; the best-fitting synchrotron temperature spectral index is
from 4.7 to 22.8 GHz and from 22.8 to
44.1 GHz. Free-free emission is weak, contributing ~K rms (~7%) at 22.8
GHz. The best explanation for the AME is still electric dipole emission from
small spinning dust grains.Comment: 18 pages, 6 figures, version matches version accepted by MNRA
Diagnostic Communication in the Memory Clinic: a Conversation Analytic Perspective
Objectives: Whether and how patients should be told their dementia diagnosis, has been an area of much debate. While there is now recognition that early diagnosis is important for dementia care little research has looked at how dementia-related diagnostic information is actually verbally communicated. The limited previous research suggests that the absence of explicit terminology (e.g., use of the term Alzheimer's) is problematic. This paper interrogates this assumption through a conversation analysis of British naturalistic memory clinic interaction.
Method: This paper is based on video-recordings of communication within a UK memory clinic. Appointments with 29 patients and accompanying persons were recorded, and the corpus was repeatedly listened to, in conjunction with the transcripts in order to identify the segments of talk where there was an action hearable as diagnostic delivery, that is where the clinician is evaluating the patient's condition.
Results: Using a conversation analytic approach this analysis suggests that diagnostic communication, which is sensitive and responsive to the patient and their carers, is not predicated on the presence or absence of particular lexical choices. There is inherent complexity regarding dementia diagnosis, especially in the ‘early stages’, which is produced through and reflected in diagnostic talk in clinical encounters.
Conclusion: In the context of continuity of dementia care, diagnostic information is communicated in a way that conforms to intersubjective norms of minimizing catastrophic reactions in medical communication, and is sensitive to problems associated with ‘insight’ in terms of delivery and receipt or non-receipt of diagnosis
Stor variation i græspollen er en udfordring i vejledningen til allergikere - resultater fra ny dansk pollenforskning "Large variations in grass pollen concentrations are a challenge in the guidance of hayfever patients – new results from Danish research”
Pollenallergi rammer op mod en femtedel af Danmarks befolkning og forringer deres hverdag og livskvalitet. Et af de vigtigste værktøjer,en pollenallergiker har, er information om, hvornår der er pollen i luften. Denne information anvender allergikere til at planlægge indtag af medicin og tilrettelæggelse af hverdagen. Således kan de begrænse deres symptomer så meget som muligt. En primær kilde tilinformation er pollenmålinger fra Viborg og København. Ny forskning fra Aarhus Universitet (AU) og Astma Allergi Danmark afdækker, at der er væsentlige lokale forskelle I mængden af græspollen. Denne variation gælder især for dage med høje pollental. Resultaterne indikerer, at særligt på dage med høje pollental for græs er nærheden til locale kilder meget vigtig. På samme tid er de lokale
koncentrationer ikke nødvendigvis korreleret med pollenmålinger fra de nationale målestationer i Viborg og København.Information om døgnvariationen i pollen er vigtig for pollenallergikerne. De nye studier indikerer store forskelle fra dag til dag, I forhold til hvornår de højeste koncentrationer forekommer, og at dette billede ændrer sig
over pollensæsonen. Viden om døgnvariation, og hvad der styrer den, er endnu langt fra fyldestgørende i forhold til at kunne formidle denne information til pollenallergikere. Vores studier peger i retning af, at de højeste koncentrationer af græspollen hyppigst forekommer
tidligt på aftenen, men at de kan forekomme på alle tider af døgnet
Μελέτη επιπτώσεων συνδρομολόγησηςεφαρμογών σε πολυπύρηνες αρχιτεκτονικές
Understanding viral transmission dynamics within populations of reservoir hosts can facilitate greater knowledge of the spillover of emerging infectious diseases. While bat-borne viruses are of concern to public health, investigations into their dynamics have been limited by a lack of longitudinal data from individual bats. Here, we examine capture-mark-recapture (CMR) data from a species of Australian bat (Myotis macropus) infected with a putative novel Alphacoronavirus within a Bayesian framework. Then, we developed epidemic models to estimate the effect of persistently infectious individuals (which shed viruses for extensive periods) on the probability of viral maintenance within the study population. We found that the CMR data analysis supported grouping of infectious bats into persistently and transiently infectious bats. Maintenance of coronavirus within the study population was more likely in an epidemic model that included both persistently and transiently infectious bats, compared with the epidemic model with non-grouping of bats. These findings, using rare CMR data from longitudinal samples of individual bats, increase our understanding of transmission dynamics of bat viral infectious diseases
- …