2,187 research outputs found
Self-shielding printed circuit boards for high frequency amplifiers and transmitters
Printed circuit boards retaining as much copper as possible provide electromagnetic shielding between stages of the high frequency amplifiers and transmitters. Oscillation is prevented, spurious output signals are reduced, and multiple stages are kept isolated from each other, both thermally and electrically
20 cm VLA Radio-Continuum Study of M31 - Images and Point Source Catalogues DR2: Extraction of a supernova remnant sample
We present Data Release 2 of the Point Source Catalogue created from a series
of previously constructed radio-continuum images of M31 at lambda=20 cm (nu=1.4
GHz) from archived VLA observations. In total, we identify a collection of 916
unique discrete radio sources across the field of M31. Comparing these detected
sources to those listed by Gelfand et al. (2004) at lambda=92 cm, the spectral
index of 98 sources has been derived. The majority (73%) of these sources
exhibit a spectral index of alpha <-0.6, indicating that their emission is
predominantly non-thermal in nature, which is typical for background objects
and Supernova Remnants (SNRs). Additionally, we investigate the presence of
radio counterparts for some 156 SNRs and SNR candidates, finding a total of
only 13 of these object in our images within a 5 arcsec search area. Auxiliary
optical, radio and X-ray catalogs were cross referenced highlighting a small
population of SNR and SNR candidates common to multi-frequency domains
Deprivation as an outcome determinant in emergency medical admissions
Background: Deprivation in the general population predicts mortality. We have investigated its relevance to an acute medical admission, using a database of all emergency admissions to St James’ Hospital, Dublin, over a ten year period (2002-2011).
<p/>Methods: All emergency admissions, based on geocoding of residence, were allocated to a Small Area Health Research Unit (SAHRU) division, with a corresponding deprivation index. We then examined this index as a univariate (unadjusted) and independent (adjusted) predictor of 30-day in-hospital mortality.
<p/>Results: The 30-day in-hospital mortality, over the 10 year period was higher, for those in the upper half of the deprivation distribution (9.6% vs 8.6%: p = 0.002). Indeed, there was a stepwise increase in 30-day mortality over the quintiles of deprivation from 7.3% (Quintile 1) to 8.8%, 10.0%, 10.0% and 9.3% respectively. Univariate logistic regression of the deprivation indices (quintiles) against outcome showed an increased risk (p = 0.002) of a 30-day death with OR’s respectively (compared with lowest deprivation quintile) of 1.23 (95% CI 1.07, 1.40), 1.41 (95% CI 1.24, 1.60), 1.41 (95% CI 1.24, 1.61) and 1.30 (95% CI 1.14, 1.48). The deprivation index was an independent predictor of outcome in a model when adjusted for illness severity and co-morbidity. The fully adjusted OR for a 30-day death was increased by 31% (p=0.001) for patients in the upper half of the deprivation index distribution (OR 1.31: 95% CI 1.20, 1.44).
<p/>Conclusion: Deprivation independently of co-morbidity or acute illness severity is a powerful outcome predictor in acute medical admissions
Iron charge states observed in the solar wind
Solar wind measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. Solar wind Fe charge state measurements from three time periods of high speed solar wind occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow solar wind indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream
Temporal variations of the anomalous oxygen component, 1977 - 1984
A survey is of the long term temporal variations of 6.6 to 12 MeV/nucleon anomalous oxygen at 1 AU covering the period 1977 to 1984. This time interval included the recent solar maximum, with the recovery at neutron monitor energies beginning in 1982. During this time interval, 6.6 to 12 MeV/nucleon 0 fluxes decreased by at least a factor of 50, and indeed remained below the instrumental detection threshold after 1979. By late 1984, neutron monitors had recovered to roughly 1979 levels from the 1982 solar maximum, and anomalous O still remained below the detection threshold
Impact of targeted chemistries on maraging steel precipitation evolution observed using SANS and APT
Building on a previous study of the novel aerospace maraging steel known as F1E, SANS and atom probe tomography (APT) have been used to study three variant chemistries designed to impact the growth and development of either laves or β-phase precipitates. One chemistry reduced the available laves forming elements, Mo and W, resulting in a reduction in both austenitization and aging laves populations. A second chemistry reduced the β-phase forming element, Al, causing a reduction in the nucleating laves but not β-phase precipitates. Mechanical properties such as tensile, creep and hardness are examined with respect to the precipitate populations
20 cm VLA Radio-Continuum Study of M31 - Images and Point Source Catalogues
We present a series of new high-sensitivity and high-resolution
radio-continuum images of M31 at \lambda=20 cm (\nu=1.4 GHz). These new images
were produced by merging archived 20 cm radio-continuum observations from the
Very Large Array (VLA) telescope. Images presented here are sensitive to rms=60
\mu Jy and feature high angular resolution (<10"). A complete sample of
discrete radio sources have been catalogued and analysed across 17 individual
VLA projects. We identified a total of 864 unique discrete radio sources across
the field of M31. One of the most prominent regions in M31 is the ring feature
for which we estimated total integrated flux of 706 mJy at \lambda=20 cm. We
compare here, detected sources to those listed in Gelfand et al. (2004) at
\lambda=92 cm and find 118 sources in common to both surveys. The majority
(61%) of these sources exhibit a spectral index of \alpha <-0.6 indicating that
their emission is predominantly non-thermal in nature. That is more typical for
background objects.Comment: 28 pages, 25 figures, accepted for publication in the Serbian
Astronomical Journa
Identifying volcanic signals in Irish temperature observations since AD 1800
Large volcanic eruptions have been shown to affect temperature patterns to varying degrees on continental, hemispheric or global scales. However, few studies have systematically explored the influence of volcanic eruptions on temperatures at a local, Irish level. The focus of this paper is to determine the impacts of five high-magnitude low-latitude volcanic eruptions and one such Icelandic event on Irish climate over the past 200 years. Daily temperature data from the Armagh Observatory, Co. Armagh, Northern Ireland was used to assess the influence of volcanic eruptions on seasonal and yearly values through time. The paper explores volcanically-induced temperature trends by filtering out the influence of the North Atlantic Oscillation (NAO) and solar variability, and goes on to employ a variation of Superposed Epoch Analysis to identify which seasons and years are most significantly affected by large volcanic eruptions. Armagh temperatures proved particularly responsive in the spring, with a significant decrease in values in the four years following an eruption. Winter temperatures also exhibited a volcanic influence, with a small initial increase in the year of and year following an eruption, and a significant decrease in residual temperature in years two and three after the event
The conceptual design of a small solar probe /Sunblazer/
Conceptual design of Sunblazer space probe for determining electron density of solar coron
"Caring for Insiderness": Phenomenologically informed insights that can guide practice.
Understanding the ‘‘insider’’ perspective has been a pivotal strength of qualitative research. Further than this, within the more applied fields in which the human activity of ‘‘caring’’ takes place, such understanding of ‘‘what it is like’’ for people from within their lifeworlds has also been acknowledged as the foundational starting point in order for ‘‘care’’ to be caring. But we believe that more attention needs to be paid to this foundational generic phenomenon: what it means to understand the ‘‘insiderness’’ of another, but more importantly, how to act on this in caring ways. We call this human phenomenon ‘‘caring for insiderness.’’ Drawing on existing phenomenological studies of marginal caring situations at the limits of caring capability, and through a process of phenomenologically oriented reflection, we interrogated some existential themes implicit in these publications that could lead to deeper insights for both theoretical and applied purposes. The paper provides direction for practices of caring by highlighting some dangers as well as some remedies along this path
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