The earth as a radio source

The primary characteristics of radio emission from the earth's magnetosphere are summarized, the origins of these missions are considered and similarities to other astronomical radio sources discussed. The auroral kilometric radiation has features very similar to Io-related decametric radiation from Jupiter and from Saturn. The radiation at fp and 2 fp upstream of the bow shock appears to be generated by the same mechanism as type III solar radio bursts. The beaming of the auroral kilometric radiation into a cone shaped region over the polar cap has some similarity to the angular distribution of radiation from Io and to the beaming of radio emission from pulsars

High-redshift X-ray properties of the haloes of simulated disc galaxies

X-ray luminosities and surface brightness profiles of the hot gas haloes of simulated disc galaxies at redshifts z=0-2 are presented. The galaxies are extracted from fully cosmological simulations and correspond in mass to the Milky Way. We find that the bolometric X-ray luminosities of the haloes decrease by a factor 4-10 from z~1 to z~0, reflecting the decrease in the rate at which hot halo gas cools out on to the disc. At all redshifts, most of the emission is found to originate within 10-15 kpc of the disc. When combined with models in which the evolution of disc X-ray luminosity is dominated by X-ray binaries, the predicted halo luminosities at z~1 show good agreement with constraints from spiral galaxies in Chandra Deep Field data. There is an indication that haloes with a metal abundance of 0.3 solar overpredict observed X-ray luminosities at z~1, suggesting that halo metallicities are lower than this value. Prospects for direct detection of the haloes of Milky Way-sized galaxies with current and future X-ray instrumentation are discussed. It is found that XEUS should be able to single out the halo emission of highly inclined Milky Way-sized disc galaxies out to approximately z=0.3. For such galaxies in this redshift interval, we estimate a lower limit to the surface density of detectable haloes on the sky of ~10 deg^(-2). More generally, owing to their luminosity evolution, the optimum redshifts at which to observe such haloes could be 0.5<z<1, depending on their assembly history.Comment: 9 pages, 4 figures, minor corrections to conform to version accepted to MNRA

Risk of symptomatic venous thromboembolism following emergency appendicectomy in adults

BACKGROUND: Appendicectomy is the commonest intra-abdominal emergency surgical procedure, and little is known regarding the magnitude and timing of the risk of venous thromboembolism (VTE) after surgery. This study aimed to determine absolute and relative rates of symptomatic VTE following emergency appendicectomy. METHODS: A cohort study was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data of patients who had undergone emergency appendicectomy from 2001 to 2011. Crude rates and adjusted incidence rate ratios (IRRs) for VTE were calculated using Poisson regression, compared with baseline risk in the year before appendicectomy. RESULTS: A total of 13 441 patients were identified, of whom 56 (0.4 per cent) had a VTE in the first year after surgery. The absolute rate of VTE was highest during the in-hospital period, with a rate of 91.29 per 1000 person-years, which was greatest in those with a length of stay of 7 days or more (267.12 per 1000 person-years). This risk remained high after discharge, with a 19.1- and 6.6-fold increased risk of VTE in the first and second months respectively after discharge, compared with the year before appendicectomy (adjusted IRR: month 1, 19.09 (95 per cent c.i. 9.56 to 38.12); month 2, 6.56 (2.62 to 16.44)). CONCLUSION: The risk of symptomatic VTE following appendicectomy is relatively high during the in-hospital admission and remains increased after discharge. Trials of extended thromboprophylaxis are warranted in patients at particularly high risk

Mass and Hot Baryons in Massive Galaxy Clusters from Subaru Weak Lensing and AMiBA SZE Observations

We present a multiwavelength analysis of a sample of four hot (T_X>8keV) X-ray galaxy clusters (A1689, A2261, A2142, and A2390) using joint AMiBA Sunyaev-Zel'dovich effect (SZE) and Subaru weak lensing observations, combined with published X-ray temperatures, to examine the distribution of mass and the intracluster medium (ICM) in massive cluster environments. Our observations show that A2261 is very similar to A1689 in terms of lensing properties. Many tangential arcs are visible around A2261, with an effective Einstein radius \sim 40 arcsec (at z \sim 1.5), which when combined with our weak lensing measurements implies a mass profile well fitted by an NFW model with a high concentration c_{vir} \sim 10, similar to A1689 and to other massive clusters. The cluster A2142 shows complex mass substructure, and displays a shallower profile (c_{vir} \sim 5), consistent with detailed X-ray observations which imply recent interaction. The AMiBA map of A2142 exhibits an SZE feature associated with mass substructure lying ahead of the sharp north-west edge of the X-ray core suggesting a pressure increase in the ICM. For A2390 we obtain highly elliptical mass and ICM distributions at all radii, consistent with other X-ray and strong lensing work. Our cluster gas fraction measurements, free from the hydrostatic equilibrium assumption, are overall in good agreement with published X-ray and SZE observations, with the sample-averaged gas fraction of = 0.133 \pm 0.027, for our sample = (1.2 \pm 0.1) \times 10^{15} M_{sun} h^{-1}. When compared to the cosmic baryon fraction f_b = \Omega_b/\Omega_m constrained by the WMAP 5-year data, this indicates /f_b = 0.78 \pm 0.16, i.e., (22 \pm 16)% of the baryons are missing from the hot phase of clusters.Comment: accepted for publication in ApJ; high resolution figures available at http://www.asiaa.sinica.edu.tw/~keiichi/upfiles/AMiBA7/ms_highreso.pd

The design of compassionate care

Aims and objectives To investigate the tension between individual and organisational responses to contemporary demands for compassionate interactions in health care. Background Health care is often said to need more compassion among its practitioners. However, this represents a rather simplistic view of the issue, situating the problem with individual practitioners rather than focusing on the overall design of care and healthcare organisations, which have often adopted a production-line approach. Design This is a position paper informed by a narrative literature review. Methods A search of the PubMed, Science Direct and CINAHL databases for the terms compassion, care and design was conducted in the research literature published from 2000 through to mid-2013. Results There is a relatively large literature on compassion in health care, where authors discuss the value of imbuing a variety of aspects of health services with compassion including nurses, other practitioners and, ultimately, among patients. This contrasts with the rather limited attention that compassionate practice has received in healthcare curricula and the lack of attention to how compassion is informed by organisational structures and processes. We discuss how making the clinic more welcoming for patients and promoting bidirectional compassion and compassion formation in nursing education can be part of an overall approach to the design of compassionate care. Conclusions We discuss a number of ways in which compassion can be enhanced through training, educational and organisational design, through exploiting the potential of brief opportunities for communication and through initiatives involving patients and service users, as well as practitioners and service leaders. Relevance to clinical practice The development of contemporary healthcare systems could usefully address the overall design of compassionate care rather than blame individual practitioners for a lack of compassion

Disturbance Alters the Phylogenetic Composition and Structure of Plant Communities in an Old Field System

The changes in phylogenetic composition and structure of communities during succession following disturbance can give us insights into the forces that are shaping communities over time. In abandoned agricultural fields, community composition changes rapidly when a field is plowed, and is thought to reflect a relaxation of competition due to the elimination of dominant species which take time to re-establish. Competition can drive phylogenetic overdispersion, due to phylogenetic conservation of ‘niche’ traits that allow species to partition resources. Therefore, undisturbed old field communities should exhibit higher phylogenetic dispersion than recently disturbed systems, which should be relatively ‘clustered’ with respect to phylogenetic relationships. Several measures of phylogenetic structure between plant communities were measured in recently plowed areas and nearby ‘undisturbed’ sites. There was no difference in the absolute values of these measures between disturbed and ‘undisturbed’ sites. However, there was a difference in the ‘expected’ phylogenetic structure between habitats, leading to significantly lower than expected phylogenetic diversity in disturbed plots, and no difference from random expectation in ‘undisturbed’ plots. This suggests that plant species characteristic of each habitat are fairly evenly distributed on the shared species pool phylogeny, but that once the initial sorting of species into the two habitat types has occurred, the processes operating on them affect each habitat differently. These results were consistent with an analysis of correlation between phylogenetic distance and co-occurrence indices of species pairs in the two habitat types. This study supports the notion that disturbed plots are more clustered than expected, rather than ‘undisturbed’ plots being more overdispersed, suggesting that disturbed plant communities are being more strongly influenced by environmental filtering of conserved niche traits

Mismatches in Scale Between Highly Mobile Marine Megafauna and Marine Protected Areas

Marine protected areas (MPAs), particularly large MPAs, are increasing in number and size around the globe in part to facilitate the conservation of marine megafauna under the assumption that large-scale MPAs better align with vagile life histories; however, this alignment is not well established. Using a global tracking dataset from 36 species across five taxa, chosen to reflect the span of home range size in highly mobile marine megafauna, we show most MPAs are too small to encompass complete home ranges of most species. Based on size alone, 40% of existing MPAs could encompass the home ranges of the smallest ranged species, while only \u3c 1% of existing MPAs could encompass those of the largest ranged species. Further, where home ranges and MPAs overlapped in real geographic space, MPAs encompassed \u3c 5% of core areas used by all species. Despite most home ranges of mobile marine megafauna being much larger than existing MPAs, we demonstrate how benefits from MPAs are still likely to accrue by targeting seasonal aggregations and critical life history stages and through other management techniques

Mismatches in Scale Between Highly Mobile Marine Megafauna and Marine Protected Areas

Marine protected areas (MPAs), particularly large MPAs, are increasing in number and size around the globe in part to facilitate the conservation of marine megafauna under the assumption that large-scale MPAs better align with vagile life histories; however, this alignment is not well established. Using a global tracking dataset from 36 species across five taxa, chosen to reflect the span of home range size in highly mobile marine megafauna, we show most MPAs are too small to encompass complete home ranges of most species. Based on size alone, 40% of existing MPAs could encompass the home ranges of the smallest ranged species, while only \u3c 1% of existing MPAs could encompass those of the largest ranged species. Further, where home ranges and MPAs overlapped in real geographic space, MPAs encompassed \u3c 5% of core areas used by all species. Despite most home ranges of mobile marine megafauna being much larger than existing MPAs, we demonstrate how benefits from MPAs are still likely to accrue by targeting seasonal aggregations and critical life history stages and through other management techniques