17,885 research outputs found
Bi-Directional Relativistic Jets of the Radio Galaxy 1946+708: Constraints on the Hubble Constant
We present measurements of bi-directional motions in the jets of the radio
galaxy 1946+708 at z=0.101. This is a Compact Symmetric Object with striking
S-symmetry. Sensitive 15 GHz observations reveal a compact component at the
center of symmetry with a strongly inverted spectrum, that we identify as the
core. From five 4.9 GHz observations spread over 4 years we have determined the
velocities of four compact jet components. If simple kinematic models can be
applied then the inclination of the source and the bulk jet velocity can be
directly determined for any assumed value of the Hubble constant. Conversely,
the measurements already place constraints on the Hubble constant, and we show
how further observations of 1946+708 can yield an increasingly accurate
determination of H_0.Comment: in press at ApJ Letters, 12 page LaTex document includes 5 postscript
figure
Effectiveness of anonymised information sharing and use in health service, police, and local government partnership for preventing violence related injury: experimental study and time series analysis
Objective: To evaluate the effectiveness of anonymised information sharing to prevent injury related to violence. Design: Experimental study and time series analysis of a prototype community partnership between the health service, police, and local government partners designed to prevent violence. Setting: Cardiff, Wales, and 14 comparison cities designated "most similar" by the Home Office in England and Wales. Intervention After a 33 month development period, anonymised data relevant to violence prevention (precise violence location, time, days, and weapons) from patients attending emergency departments in Cardiff and reporting injury from violence were shared over 51 months with police and local authority partners and used to target resources for violence prevention. Main outcome measures: Health service records of hospital admissions related to violence and police records of woundings and less serious assaults in Cardiff and other cities after adjustment for potential confounders. Results: Information sharing and use were associated with a substantial and significant reduction in hospital admissions related to violence. In the intervention city (Cardiff) rates fell from seven to five a month per 100 000 population compared with an increase from five to eight in comparison cities (adjusted incidence rate ratio 0.58, 95% confidence interval 0.49 to 0.69). Average rate of woundings recorded by the police changed from 54 to 82 a month per 100 000 population in Cardiff compared with an increase from 54 to 114 in comparison cities (adjusted incidence rate ratio 0.68, 0.61 to 0.75). There was a significant increase in less serious assaults recorded by the police, from 15 to 20 a month per 100 000 population in Cardiff compared with a decrease from 42 to 33 in comparison cities (adjusted incidence rate ratio 1.38, 1.13 to 1.70). Conclusion: An information sharing partnership between health services, police, and local government in Cardiff, Wales, altered policing and other strategies to prevent violence based on information collected from patients treated in emergency departments after injury sustained in violence. This intervention led to a significant reduction in violent injury and was associated with an increase in police recording of minor assaults in Cardiff compared with similar cities in England and Wales where this intervention was not implemented
Flash Point and Chemical Composition of Aviation Kerosene (Jet A)
The relationship between chemical composition, flash point, and ignition energy was examined for eight samples of aviation kerosene (Jet A) with flash points between 29°C (84°F) and 74°C (165°F). We report the results of liquid characterization by two different laboratories. We use the results of headspace gas chromatography carried out by Woodrow and Seiber to characterize the vapor composition at liquid mass loading fractions of 3 and 400 kg/m^3. The composition data were analyzed to obtain analytical representations of vapor pressure and average molar mass as a function of temperature for each flash point fuel. The relationship between composition and flash point is examined by using two prediction methods. The first method is based on the notion of a critical value of fuel-air mass ratio at the flammability limit. The second method is based on Le Chatelier's rule for flammability limits. Both methods show a reasonable correlation between measured and predicted flash point. The relationship between flash point and ignition temperature threshold at a fixed spark ignition energy was examined for four fuels. A linear correlation was obtained for an ignition energy of 0.3 J. The effect of fuel weathering was examined by determining the flashpoints of seven fuel samples obtained from flight tests. The flash point increased about 8°C for fuel that had been exposed to 5 take-off, cruise, and landing cycles
Water utilization, evapotranspiration and soil moisture monitoring in the south east region of south Australia
There are no author-identified significant results in this report
Detection of Optical Synchrotron Emission from the Radio Jet of 3C279
We report the detection of optical and ultraviolet emission from the
kiloparsec scale jet of the well-known quasar 3C~279. A bright knot, discovered
in archival V and U band {\it Hubble Space Telescope} Faint Object Camera
images, is coincident with a peak in the radio jet \sim0.6\arcsec from the
nucleus. The detection was also confirmed in Wide Field Planetary Camera-2
images. Archival Very Large Array and MERLIN radio data are also analyzed which
help to show that the high-energy optical/UV continuum, and spectrum, are
consistent with a synchrotron origin from the same population of relativistic
electrons responsible for the radio emission.Comment: 6 pages, 3 figs. accepted for publication in ApJL with minor
revision
HIV positive patient with GBS-like syndrome
Introduction. GuillainâBarrĂ© Syndrome (GBS) is an acute demyelinating polyneuropathy which can occur post-infection. Criteria of diagnosis of GBS include areflexia with progressive bilateral weakness in arms and legs. GBS can lead to severe respiratory and cardiac complications. The fatality rate can be up to 5â% in patients, depending on the severity of the symptoms. HIV can cause a range of neurological disorders including, on rare occasions, GBS. GBS can occur at any stage of HIV infection, highlighting the complexity of diagnosis of GBS within HIV patients.
Case presentation. A 57âyear old female with lumbar back pain radiating to the legs, poor mobility and tiredness, with reports of a viral-like illness four days previously, was initially diagnosed with a lower respiratory tract infection and discharged. Seventeen days later the patient was readmitted to hospital with progressive lower and upper limb weakness, areflexia and sensory loss. She was diagnosed with GBS and was unexpectedly discovered to be HIV-positive. HIV avidity was low indicating a recently acquired HIV infection. The patient was treated with intravenous immunoglobulin for fiveâdays for the GBS and commenced antriretrovirals for HIV. The patient was discharge from hospital 53âdays after admission with walking aids and regular physiotherapy follow-up.
Conclusion. This case highlighted the need for all clinicians to be aware that patients with symptoms of GBS, regardless of clinical history should be offered an HIV test. GBS can be the first sign a patient is HIV-positive
The socioeconomic pattern of health and developmental outcomes among Aboriginal and Torres Strait Islander children
The pervasive health and social disadvantage faced by Aboriginal and Torres Strait Islander peoples is an acknowledged part of Australian society. The contemporary data reveal striking inequalities between Indigenous and non-Indigenous Australians in most measurable aspects of wellbeing across the life cycle. This reflects a postcolonial history of marginalisation and exclusion from mainstream society, dispossession of traditional lands, forced separation from family and kinship networks, and racism. Despite an increased awareness and disapproval of these inequalities in health, the inequalities persist.The lack of progress in the face of public disapproval and progressive government support underscores the fact that we still do not adequately understand the fundamental causes of Indigenous ill health and disease. A small body of research in Australia has highlighted that socioeconomic status (SES) accounts for a portion of the gap in health but this does not imply that they account for health differences within Indigenous population groups. A robust international literature has consistently shown that socioeconomic factors influence population health. These factors reflect the way in which society is ordered according to wealth, prestige, power, social standing or oneâs control over economic resources, and their pattern of association with health has almost always depicted better health for those who are better offâ that is, the health of population groups normally follows a gradient pattern. Despite the ubiquity of this observation in the empirical literature, there is uncertainty as to whether it applies to Aboriginal and Torres Strait Islander populations in Australia.Accordingly, this thesis has aimed to assess the pattern of socioeconomic disparities in the health and development of Indigenous populations in Australia, with a specific focus on children. The three key objectives were to: âą Describe the developmental status of Indigenous children and the mechanisms that influence this status; âą Determine the pattern of association between socioeconomic factors and physical and mental health outcomes; and âą Reveal the significant differences (and similarities) in the socioeconomic pattern of child health between Indigenous and non-Indigenous populations, and articulate these in terms of their direction, shape and magnitude.The objectives of the study were primarily assessed using a quantitative analytic framework applied to four existing population-representative datasets: the 2008 National Aboriginal and Torres Strait Islander Social Survey, the 2000â2002 Western Australian Aboriginal Child Health Survey, the 2004â05 National Aboriginal and Torres Strait Islander Health Survey and 2004â05 National Health Survey. Simple univariate and cross-tabulation data were used to describe population characteristics, while the relationships between socioeconomic indicators and health outcomes were assessed using a range of regression techniques. Multilevel models are an important feature of this study, and have enabled a more accurate estimation of the effects of individual and area-level measures of SES on health. Generalised Additive Models were used to account for the possible non-linear nature of associations between continuous SES variables and physical health outcomes, with results presented as non-parametric spline curves. The mechanisms linking SES and mental health were explored using a stepwise approach to the regression analysis. All data in all chapters were weighted to reflect population benchmarks.The findings highlighted that there were significant socioeconomic disparities in the health of Indigenous children in Australia, although the direction, shape and magnitude varied, by both socioeconomic measure and health outcome. While the socioeconomic patterns of Indigenous child health are not universal, they are more consistent for mental than physical health. In addition, the thesis has shown that both conventional and alternative notions of SES can influence health patterns. The largest disparities in child physical health were observed for area-level SES indicators, while housing characteristics and area-level SES both had a strong direct effect on child mental health.The thesis has demonstrated that the patterns of socioeconomic disparities in child health differ markedly in Indigenous and non-Indigenous populationsâat least in non-remote settings. It was not uncommon for the magnitude of disparity to be larger in the Indigenous population. These findings lend support to the notion that socioeconomic factors have a differential impact on the health of Indigenous and non-Indigenous populations. The implication of this for policy is that a single approach to stimulating socioeconomic conditions will not have equal benefits to child health outcomes in Indigenous and non-Indigenous populations. While the evidence here underscores the validity of the well-worn edict that âone size does not fit allâ in Indigenous health policy, it also reinforces the need to examine health disparities within and across Indigenous and other population groups in order to better inform policy and practiceCollectively, the results have provided clear evidence that socioeconomic factors matter to both the physical and mental health of Aboriginal and Torres Strait Islander children. The diversity of findings implies that SES factors are one facet of the unique and complex set of factors that influence Aboriginal child health and wellbeing.This thesis has made several original contributions to the literature on social inequalities in Indigenous health in Australia and the broader field of social determinants of health. It is one of the few studies internationally to explicitly look at the socioeconomic patterning of health in an Indigenous population, and the first to examine these patterns among Indigenous children using population-representative data. In doing so, the study has begun to bridge the knowledge gap on social inequalities in Aboriginal health in Australia, and will facilitate a better grasp of the complex underlying mechanisms that determine Aboriginal health.For policy, this knowledge can lead to more effective government decision-making in terms of targeting social determinants of health that are of particular significance for Aboriginal populations. It is hoped that the findings of the thesis can provide directions for future research and insights to policy that will, ultimately, increase the pace of change toward health equity in Australia
Resolved CO(1-0) Nuclei in IRAS 14348-1447: Evidence for Massive Bulge Progenitors to Ultraluminous Infrared Galaxies
High-resolution, CO(1-0) interferometry of the ultraluminous infrared galaxy
IRAS 14348-1447 is presented. The merger system has a molecular gas mass of
\~3x10^10 solar masses and a projected nuclear separation of 4.8 kpc (3.5"),
making it one of the most molecular gas-rich galaxies known and an ideal
candidate for studying the intermediate stages of an ultraluminous merger
event. The CO morphology shows two molecular gas components associated with the
stellar nuclei of the progenitors, consistent with the idea that the molecular
disks are gravitationally bound by the dense bulges of the progenitor galaxies
as the interaction proceeds. In contrast, less luminous infrared galaxies
observed to date with projected nuclear separations of ~<5 kpc show a dominant
CO component between the stellar nuclei. This discrepancy may be an indication
that the progenitors of mergers with lower infrared luminosity do not possess
massive bulges, and that the gas is stripped during the initial encounter of
their progenitors. A comparison of the CO and radio luminosities of the NE and
SW component show them to have comparable radio and CO flux ratios of
f(NE)/f(SW) ~0.6, possibly indicating that the amount of star-forming molecular
gas in the progenitors is correlated with the supernovae rate. The estimate of
molecular gas masses of the nuclei and the extent of the radio emission are
used to infer that the nuclei of IR 14348-1447 have gas densities comparable to
the cores of elliptical galaxies.Comment: LaTex, 5 pages with 1 postscript and 1 jpg figure, ApJ Letters, in
pres
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