A 4.8- and 8.6-GHz Survey of the Large Magellanic Cloud: I The Images

Detailed 4.8- and 8.6-GHz radio images of the entire Large Magellanic Cloud with half-power beamwidths of 33" at 4.8 GHz and 20" at 8.6 GHz have been obtained using the Australia Telescope Compact Array. A total of 7085 mosaic positions were used to cover an area of 6 degrees on a side. Full polarimetric observations were made. These images have sufficient spatial resolution (~8 and 5 pc, respectively) and sensitivity (3-sigma of 1 mJy/beam) to identify most of the individual SNRs and H II regions and also, in combination with available data from the Parkes 64-m telescope, the structure of the smooth emission in that galaxy. In addition, limited data using the sixth antenna at 4.5 to 6-km baselines are available to distinguish bright point sources (<3 and 2 arcsec, respectively) and to help estimate sizes of individual sources smaller than the resolution of the full survey. The resultant database will be valuable for statistical studies and comparisons with x-ray, optical and infrared surveys of the LMC with similar resolution.Comment: 28 pages, 10 figures, 2 tables, accepted for publication in the Feb 2005 A

A search for molecules in damped Lyman-alpha absorbers occulting millimetre-loud quasars

We have used the SEST 15-metre and Onsala 20-metre telescopes to perform deep (r.m.s. >~ 30 mJy) integrations of various molecular rotational transitions towards damped Lyman-alpha absorption systems (DLAs) known to occult millimetre-loud quasars. We have observed 6 new systems and improved the existing limits for 11 transitions. These limits may be approaching the sensitivities required to detect new systems and we present a small number of candidate systems which we believe warrant further observation.Comment: 7 pages, 1 PS figure, 4 tables. Accepted by A&

Temporal variability in large grazer space use in an experimental landscape

Land use, climate change, and their interaction each have great potential to affect grazing systems. With anticipated more frequent and extensive future drought, a more complete understanding of the mechanisms that determine large grazer landscape-level distribution under varying climatic conditions is integral to ecosystem management. Using an experimental setting with contrasting fire treatments, we describe the inter-annual variability of the effect of landscape topography and disturbance from prescribed spring fire on large grazer space use in years of variable resource availability. Using GPS telemetry, we investigated space use of plains bison (Bison bison bison) as they moved among watersheds managed with variable experimental burn treatments (1-, 2-, 4-, and 20-year burn intervals) during a seven-year period spanning years of average-to-above average forage production and severe drought. At the landscape scale, bison more strongly favored high-elevation and recently burned watersheds with watersheds burned for the first time in 2 or 4 yr consistently showing higher use relative to annually burned watersheds. In particular, watersheds burned for the first time in 4 yr were avoided to lesser extent than other more frequently burned watersheds during the dormant season. This management type also maintained coupling between bison space use and post-fire regrowth across post-drought growing season months, whereas watersheds with more frequent fire-return intervals attracted bison in only the first month post-fire. Hence, fire frequency played a role in maintaining the coupling of grazer and post-fire regrowth, the fire–grazer interaction, in response to drought-induced reduction in fuel loads. Moreover, bison avoided upland habitat in poor forage production years, when forage regrowth is less likely to occur in upland than in lowland habitats. Such quantified responses of bison to landscape features can aid future conservation management efforts and planning to sustain fire–grazer interactions and resulting spatial heterogeneity in grassland ecosystems

Temporal variability in large grazer space use in an experimental landscape

Land use, climate change, and their interaction each have great potential to affect grazing systems. With anticipated more frequent and extensive future drought, a more complete understanding of the mechanisms that determine large grazer landscape-level distribution under varying climatic conditions is integral to ecosystem management. Using an experimental setting with contrasting fire treatments, we describe the inter-annual variability of the effect of landscape topography and disturbance from prescribed spring fire on large grazer space use in years of variable resource availability. Using GPS telemetry, we investigated space use of plains bison (Bison bison bison) as they moved among watersheds managed with variable experimental burn treatments (1-, 2-, 4-, and 20-year burn intervals) during a seven-year period spanning years of average-to-above average forage production and severe drought. At the landscape scale, bison more strongly favored high-elevation and recently burned watersheds with watersheds burned for the first time in 2 or 4 yr consistently showing higher use relative to annually burned watersheds. In particular, watersheds burned for the first time in 4 yr were avoided to lesser extent than other more frequently burned watersheds during the dormant season. This management type also maintained coupling between bison space use and post-fire regrowth across post-drought growing season months, whereas watersheds with more frequent fire-return intervals attracted bison in only the first month post-fire. Hence, fire frequency played a role in maintaining the coupling of grazer and post-fire regrowth, the fire–grazer interaction, in response to drought-induced reduction in fuel loads. Moreover, bison avoided upland habitat in poor forage production years, when forage regrowth is less likely to occur in upland than in lowland habitats. Such quantified responses of bison to landscape features can aid future conservation management efforts and planning to sustain fire–grazer interactions and resulting spatial heterogeneity in grassland ecosystems

The covering factor of high redshift damped Lyman-α\alpha systems

We have used the Very Long Baseline Array to image 18 quasars with foreground damped Lyman-$\alpha$ systems (DLAs) at 327, 610 or 1420 MHz, to measure the covering factor $f$ of each DLA at or near its redshifted HI 21cm line frequency. Including six systems from the literature, we find that none of 24 DLAs at $0.09 < z < 3.45$ has an exceptionally low covering factor, with $f \sim 0.45 - 1$ for the 14 DLAs at $z > 1.5$, $f \sim 0.41 - 1$ for the 10 systems at $z < 1$, and consistent covering factor distributions in the two sub-samples. The observed paucity of detections of HI 21cm absorption in high-$z$ DLAs thus cannot be explained by low covering factors and is instead likely to arise due to a larger fraction of warm HI in these absorbers.Comment: 6 pages, 20 figures; MNRAS (Letters), in pres

Longitudinal evaluation of peritoneal macrophage function and activation during CAPD: Maturity, cytokine synthesis and arachidonic acid metabolism

Longitudinal evaluation of peritoneal macrophage function and activation during CAPD: Maturity, cytokine synthesis and arachidonic acid metabolism. The release of cytokines and prostaglandins (PG) by peritoneal macrophages (PMØ) may influence the cytokine network controlling peritoneal inflammation and in the long-term the function of the peritoneum as a dialysis membrane. In the present study, an evaluation of the long-term effects of peritoneal dialysis on the release of cytokines and prostaglandins, and the expression of surface markers of cellular maturation on blood and mononuclear cells has been performed in patients during their first year on CAPD. Spontaneous release of tumour necrosis factor α (TNFα) and interleukin 6 (IL-6) by PMØ, after 4 or 24 hours in culture, increased significantly with time on CAPD, while there was a small but significant decrease in release of prostaglandin E2 (PGE2). Production of TNFα and IL-6 was enhanced following incubation of the cells with lipopolysaccharide (LPS), but the effect of LPS was proportionally greater on blood monocytes than on PMØ. There was a significant increase in the concentrations of PGE2 and 6-keto-prostaglandin F1α in overnight dwell peritoneal dialysis effluent with time on CAPD. The levels of TNFα and IL-6 in uninfected PDE were below the detection limit of the immunoassay over the whole time period studied. Expression of CD15, which correlates with immaturity, by PMØ and blood monocytes increased with time on CAPD, while expression of CD11c, a marker of maturation, decreased on blood monocytes, but did not change significantly on PMØ. There was also a slight increase in expression of transferrin receptor in both PMØ and monocytes, but this did not reach statistical significance. These findings suggest that peritoneal macrophages and blood monocytes isolated from CAPD patients over a one year period become increasingly immature with time, and this is accompanied by a significant modulation of their ability to secrete inflammatory cytokines. Dysregulation of macrophage function may have important consequences with respect to inflammatory processes and the long-term function of the peritoneal membrane in CAPD patients

Understanding dental students’ use of feedback

Introduction Feedback can enhance learning and is thought to be highly valued by students; however, it is not clear from the literature how dental students actually use feedback. Aim This study aimed to explore how dental students use feedback in a variety of contexts. Methods Qualitative methods involving audio‐recorded focus groups were used to explore the use of feedback by undergraduate dental students studying at three UK dental schools. A purposive sampling strategy was used to ensure diverse representation across the undergraduate dental programmes in each of the schools. Results Six focus groups, involving a total of 72 students, were undertaken. Thematic analysis identified five main themes relating to the use of feedback: value, future applicability, accessibility, variability and understanding. The inter‐connectivity and interaction of the themes (along with their subthemes) were used to develop a model for optimising feedback with the aim of enhancing its potential use by students. Conclusion The use of feedback by students would appear to be strongly influenced by several factors. Understanding these factors and how they interlink may be helpful to education providers who are seeking to optimise their feedback processes

One-way multigrid method in electronic structure calculations

We propose a simple and efficient one-way multigrid method for self-consistent electronic structure calculations based on iterative diagonalization. Total energy calculations are performed on several different levels of grids starting from the coarsest grid, with wave functions transferred to each finer level. The only changes compared to a single grid calculation are interpolation and orthonormalization steps outside the original total energy calculation and required only for transferring between grids. This feature results in a minimal amount of code change, and enables us to employ a sophisticated interpolation method and noninteger ratio of grid spacings. Calculations employing a preconditioned conjugate gradient method are presented for two examples, a quantum dot and a charged molecular system. Use of three grid levels with grid spacings 2h, 1.5h, and h decreases the computer time by about a factor of 5 compared to single level calculations.Comment: 10 pages, 2 figures, to appear in Phys. Rev. B, Rapid Communication

Mothers behaving badly: chaotic hedonism and the crisis of neoliberal social reproduction

This article focuses on the significance of the plethora of representations of mothers ‘behaving badly’ in contemporary anglophone media texts, including the films Bad Moms, Fun Mom Dinner and Bad Mom’s Christmas, the book and online cartoons Hurrah for Gin and the recent TV comedy dramas Motherland, The Let Down and Catastrophe. All these media texts include representations of, first, mothers in the midst of highly chaotic everyday spaces where any smooth routine of domesticity is conspicuous by its absence; and second, mothers behaving hedonistically, usually through drinking and partying, behaviour that is more conventionally associated with men or women without children. After identifying the social type of the mother behaving badly (MBB), the article locates and analyses it in relation to several different social and cultural contexts. These contexts are: a neoliberal crisis in social reproduction marked by inequality and overwork; the continual if contested role of women as ‘foundation parents’; and the negotiation of longer-term discourses of female hedonism. The title gestures towards a popular British sitcom of the 1990s, Men Behaving Badly, which popularized the idea of the ‘new lad’; and this article suggests that the new lad’s counterpart, the ladette, is mutating into the mother behaving badly, or the ‘lad mom’. Asking what work this figure does now, in a later neoliberal context, it argues that the mother behaving badly is simultaneously indicative of a widening and liberating range of maternal subject positions and symptomatic of a profound contemporary crisis in social reproduction. By focusing on the classed and racialised dynamics of the MBB – by examining who exactly is permitted to be hedonistic, and how – and by considering the MBB’s limited and partial imagining of progressive social change, the article concludes by emphasizing the urgency of creating more connections between such discourses and ‘parents behaving politically’

A population-based audit of ethnicity and breast cancer risk in one general practice catchment area in North London, UK: implications for practice

<p>Abstract</p> <p>Objectives</p> <p>To conduct a pilot population-based study within a general practice catchment area to determine whether the incidence of breast cancer was increased in the Ashkenazi population.</p> <p>Design</p> <p>Population-based cohort study.</p> <p>Setting</p> <p>A single general practice catchment area in North London.</p> <p>Participants</p> <p>1947 women over the age of 16 who responded to a questionnaire about ethnicity and breast cancer.</p> <p>Main outcome measures</p> <p>Incidence of breast cancer, ethnicity.</p> <p>Results</p> <p>This study showed a 1.5-fold (95% CI 0.93–2.39) increase in breast cancer risk in the Ashkenazim compared with the non-Ashkenazi white population. The increased incidence was for both premenopausal and postmenopausal breast cancer (expected incidence pre:post is 1:4 whereas in the Ashkenazim it was 1:1; 51 and 52% of cases respectively). This increase was not shown in the Sephardim. Asians had a reduction in incidence (OR = 0.44; 95% CI 0.10–1.89). Results were adjusted for other risk factors for breast cancer.</p> <p>Conclusion</p> <p>This study showed a 1.5-fold increase in breast cancer rates in Ashkenazim compared with the non-Jewish white population when adjusted for age (i.e. corrections were made to allow comparison of age groups) and this is not observed in the Sephardic population. The proportion of premenopausal breast cancer was just over double that of the general population. This is the first general practice population-based study in the UK to address this issue and has implications for general practitioners who care for patients from the Ashkenazi community.</p