A complete sample of 21-cm absorbers at z~1.3: Giant Metrewave Radio Telescope Survey Using MgII Systems

We present the results of a systematic Giant Metrewave Radio Telescope (GMRT) survey of 21-cm absorption in a representative and unbiased sample of 35 strong MgII systems in the redshift range: zabs~1.10-1.45, 33 of which have W_r>1 \AA. The survey using ~400hrs of telescope time has resulted in 9 new 21-cm detections and stringent 21-cm optical depth upper limits (median 3-sigma optical depth per 10 km/s of 0.017) for the remaining 26 systems. This is by far the largest number of 21-cm detections from any single survey of intervening absorbers. Prior to our survey no intervening 21-cm system was known in the above redshift range and only one system was known in the redshift range 0.7<z<1.5. We discuss the relation between the detectability of 21-cm absorption and various properties of UV absorption lines. We show that if MgII systems are selected with the following criteria, MgII doublet ratio <1.3 and W_r(MgI)/W_r(MgII)>0.3, then a detection rate of 21-cm absorption up to 90% can be achieved. We estimate n_{21}, the number per unit redshift of 21-cm absorbers with W_r(Mg(II)>W_o and integrated optical depth Tau_{21}>Tau_o and show that n_{21} decreases with increasing redshift. In particular, for W_o=1.0 \AA and Tau_o>0.3 km\s, n_{21} falls by a factor 4 from =0.5 to =1.3. The evolution seems to be stronger for stronger MgII systems. Using a subsample of systems for which high frequency VLBA images are available, we show that the effect is not related to the structure of the background radio sources and is most probably due to the evolution of the cold neutral medium filling factor in MgII systems. We find no correlation between the velocity spread of the 21-cm absorption feature and W_r(MgII) at z~1.3.Comment: 22 pages, 8 tables, 12 figures, accepted for publication in MNRA

Drug resistance and viral tropism in HIV-1 subtype C-infected patients in KwaZulu-Natal, South Africa: implications for future treatment options

Article approval pendingDrug resistance poses a significant challenge for the successful application of highly active antiretroviral therapy (HAART) globally. Furthermore, emergence of HIV-1 isolates that preferentially use CXCR4 as a coreceptor for cell entry, either as a consequence of natural viral evolution or HAART use, may compromise the efficacy of CCR5 antagonists as alternative antiviral therapy

Patterns and frequency of anxiety in women undergoing gynaecological surgery

Patterns and frequency of anxiety in women undergoing gynaecological surgery Aims. Within a gynaecological surgical setting to identify the patterns and frequency of anxiety pre- and postoperatively; to identify any correlation between raised anxiety levels and postoperative pain; to identify events, from the patients’ perspective, that may increase or decrease anxiety in the pre- and postoperative periods. Background. It is well documented that surgery is associated with increased anxiety, which has an adverse impact on patient outcomes. Few studies have been conducted to obtain the patient’s perspective on the experience of anxiety and the events and situations that aggravate and ameliorate it. Method. The study used a mixed method approach. The sample consisted of women undergoing planned gynaecological surgery. Anxiety was assessed using the State Trait Anxiety Inventory. Trait anxiety was measured at the time of recruitment. State anxiety was then assessed at six time points during the pre- and postoperative periods. Postoperative pain was also measured using a 10 cm visual analogue scale. Taped semi-structured telephone interviews were conducted approximately a week after discharge. Results. State anxiety rose steadily from the night before surgery to the point of leaving the ward to go to theatre. Anxiety then increased sharply prior to the anaesthetic decreasing sharply afterwards. Patients with higher levels of trait anxiety were more likely to experience higher levels of anxiety throughout their admission. Elevated levels of pre- and postoperative anxiety were associated with increased levels of postoperative pain. Telephone interviews revealed a range of events/situations that patients recalled distressing them and many were related to inadequate information. Conclusion. This study found higher rates of anxiety than previously reported and anxiety levels appeared raised before admission to hospital. This has important clinical and research implications.Relevance to clinical practice. Patients with high levels of anxiety may be identified preoperatively and interventions designed to reduce anxiety could be targeted to this vulnerable group. Patient experiences can inform the delivery of services to meet their health needs better

The Murchison Widefield Array Transients Survey (MWATS). A search for low frequency variability in a bright Southern hemisphere sample

We report on a search for low-frequency radio variability in 944 bright (> 4Jy at 154 MHz) unresolved, extragalactic radio sources monitored monthly for several years with the Murchison Widefield Array. In the majority of sources we find very low levels of variability with typical modulation indices < 5%. We detect 15 candidate low frequency variables that show significant long term variability (>2.8 years) with time-averaged modulation indices M = 3.1 - 7.1%. With 7/15 of these variable sources having peaked spectral energy distributions, and only 5.7% of the overall sample having peaked spectra, we find an increase in the prevalence of variability in this spectral class. We conclude that the variability seen in this survey is most probably a consequence of refractive interstellar scintillation and that these objects must have the majority of their flux density contained within angular diameters less than 50 milli-arcsec (which we support with multi-wavelength data). At 154 MHz we demonstrate that interstellar scintillation time-scales become long (~decades) and have low modulation indices, whilst synchrotron driven variability can only produce dynamic changes on time-scales of hundreds of years, with flux density changes less than one milli-jansky (without relativistic boosting). From this work we infer that the low frequency extra-galactic southern sky, as seen by SKA-Low, will be non-variable on time-scales shorter than one year.Comment: 19 pages, 11 figure

Florence Nightingale's legacy for clinical academics: A framework analysis of a clinical professorial network and a model for clinical academia.

BACKGROUND: Clinical academic nursing roles are rare, and clinical academic leadership positions even more scarce. Amongst the United Kingdom (UK) academia, only 3% of nurses who are employed within universities are clinically active. Furthermore, access to research fellowships and research grant funding for nurses in clinical or academic practice is also limited. The work of Florence Nightingale, the original role model for clinical academic nursing, is discussed in terms of how this has shaped and influenced that of clinical academic nurse leaders in modern UK healthcare settings. We analysed case studies with a view to providing exemplars and informing a new model by which to visualise a trajectory of clinical academic careers. METHODS: A Framework analysis of seven exemplar cases was conducted for a network of Clinical Academic Nursing Professors (n = 7), using a structured template. Independent analysis highlighted shared features of the roles: (a) model of clinical academic practice, (b) infrastructure for the post, (c) capacity-building initiatives, (d) strategic influence, (e) wider influence, (f) local and national implementation initiatives, (g) research area and focus and (h) impact and contribution. FINDINGS: All seven of the professors of nursing involved in this discourse were based in both universities and healthcare organisations in an equal split. All had national and international profiles in their specialist clinical areas and were implementing innovation in their clinical and teaching settings through boundary spanning. We outline a model for career trajectories in clinical academia, and how leadership is crucial. CONCLUSION: The model outlined emphasises the different stages of clinical academic roles in nursing. Nursing as a discipline needs to embrace the value of these roles, which have great potential to raise the standards of healthcare and the status of the profession

Automatic classification of flying bird species using computer vision techniques [forthcoming]

Bird populations are identified as important biodiversity indicators, so collecting reliable population data is important to ecologists and scientists. However, existing manual monitoring methods are labour-intensive, time-consuming, and potentially error prone. The aim of our work is to develop a reliable automated system, capable of classifying the species of individual birds, during flight, using video data. This is challenging, but appropriate for use in the field, since there is often a requirement to identify in flight, rather than while stationary. We present our work, which uses a new and rich set of appearance features for classification from video. We also introduce motion features including curvature and wing beat frequency. Combined with Normal Bayes classifier and a Support Vector Machine classifier, we present experimental evaluations of our appearance and motion features across a data set comprising 7 species. Using our appearance feature set alone we achieved a classification rate of 92% and 89% (using Normal Bayes and SVM classifiers respectively) which significantly outperforms a recent comparable state-of-the-art system. Using motion features alone we achieved a lower-classification rate, but motivate our on-going work which we seeks to combine these appearance and motion feature to achieve even more robust classification

Predictions for ASKAP Neutral Hydrogen Surveys

The Australian Square Kilometer Array Pathfinder (ASKAP) will revolutionise our knowledge of gas-rich galaxies in the Universe. Here we present predictions for two proposed extragalactic ASKAP neutral hydrogen (HI) emission-line surveys, based on semi-analytic models applied to cosmological N-body simulations. The ASKAP HI All-Sky Survey, known as WALLABY, is a shallow 3 Pi survey (z = 0 - 0.26) which will probe the mass and dynamics of over 600,000 galaxies. A much deeper small-area HI survey, called DINGO, aims to trace the evolution of HI from z = 0 - 0.43, a cosmological volume of 40 million Mpc^3, detecting potentially 100,000 galaxies. The high-sensitivity 30 antenna ASKAP core (diameter ~2 km) will provide an angular resolution of 30 arcsec (at z=0). Our simulations show that the majority of galaxies detected in WALLABY (87.5%) will be resolved. About 5000 galaxies will be well resolved, i.e. more than five beams (2.5 arcmin) across the major axis, enabling kinematic studies of their gaseous disks. This number would rise to 160,000 galaxies if all 36 ASKAP antennas could be used; the additional six antennas provide baselines up to 6 km, resulting in an angular resolution of 10 arcsec. For DINGO this increased resolution is highly desirable to minimise source confusion; reducing confusion rates from a maximum of 10% of sources at the survey edge to 3%. We estimate that the sources detected by WALLABY and DINGO will span four orders of magnitude in total halo mass (from 10^{11} to 10^{15} Msol) and nearly seven orders of magnitude in stellar mass (from 10^{5} to 10^{12} Msol), allowing us to investigate the process of galaxy formation across the last four billion years.Comment: 21 pages, accepted for publication in MNRAS, minor updates to published version and fixed links. Movies and images available at http://ict.icrar.org/store/Movies/Duffy12c

Security: Collective good or commodity?

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2008 Sage.The state monopoly on the legitimate use of violence in Europe and North America has been central to the development of security as a collective good. Not only has it institutionalized the state as the prime national and international security provider, it has helped to reduce the threat from other actors by either prohibiting or limiting their use of violence. The recent growth of the private security industry appears to undermine this view. Not only are private security firms proliferating at the national level; private military companies are also taking over an increasing range of military functions in both national defence and international interventions. This article seeks to provide an examination of the theoretical and practical implications of the shift from states to markets in the provision of security. Specifically, it discusses how the conceptualization of security as a commodity rather than a collective good affects the meaning and implementation of security in Western democracies.ESR

The FirstMurchisonWidefield Array low-frequency radio observations of cluster scale non-thermal emission: the case of Abell 3667

We present the first Murchison Widefield Array observations of the well-known cluster of galaxies Abell 3667 (A3667) between 105 and 241 MHz. A3667 is one of the best known examples of a galaxy cluster hosting a double radio relic and has been reported to contain a faint radio halo and bridge. The origin of radio haloes, relics and bridges is still unclear, however galaxy cluster merger seems to be an important factor. We clearly detect the north-west (NW) and south-east radio relics in A3667 and find an integrated flux density at 149MHz of 28.1 ± 1.7 and 2.4 ± 0.1 Jy, respectively, with an average spectral index, between 120 and 1400 MHz, of -0.9 ± 0.1 for both relics. We find evidence of a spatial variation in the spectral index across the NW relic steepening towards the centre of the cluster, which indicates an ageing electron population. These properties are consistent with higher frequency observations. We detect emission that could be associated with a radio halo and bridge. However, due to the presence of poorly sampled large-scale Galactic emission and blended point sources we are unable to verify the exact nature of these features