The distribution of species range size: a stochastic process

The major role played by environmental factors in determining the geographical range sizes of species raises the possibility of describing their long-term dynamics in relatively simple terms, a goal which has hitherto proved elusive. Here we develop a stochastic differential equation to describe the dynamics of the range size of an individual species based on the relationship between abundance and range size, derive a limiting stationary probability model to quantify the stochastic nature of the range size for that species at steady state, and then generalize this model to the species-range size distribution for an assemblage. The model fits well to several empirical datasets of the geographical range sizes of species in taxonomic assemblages, and provides the simplest explanation of species-range size distributions to date

High Spectral and Spatial Resolution Observations of Shocked Molecular Hydrogen at the Galactic Center

The presence of OH (1720 MHz) masers, and the absence of counterparts at 1665/1667 MHz has proved to be a clear diagnostic of shocked molecular gas associated with Galactic supernova remnants. This suggests that shocked molecular gas should be associated with the OH (1720 MHz) masers that have been detected in the circumnuclear disk (CND) and Sgr A East at the Galactic center. In order to test this hypothesis, we observed the H$_2$ 1--0 S(1) and Br $\gamma$ lines using NICMOS on the HST and UNSWIRF on the AAT, near the regions where OH (1720 MHz) masers are detected in the CND and Sgr A East. We present the distribution of H$_2$ in the North and South lobes of the CND and in Sgr A East. H$_2$ emission accompanies almost all of the maser spots detected at the Galactic center. In particular, we find a striking filamentary structure near the Northwest of the CND and evidence that shocked molecular gas is associated with the 70 \kms molecular cloud at the Galactic center. We argue that the emission from the CND could arise in gas heated by the dissipation of the random motion of clumps by collisions or the dissipation of turbulence in a more homogeneous medium. In addition, highly red-shifted gas of up to 140 \kms\ close to the eastern edge of the Sgr A East shell is detected. These observations combined with OH (1720 MHz) results suggest that the H$_2$ gas is shocked and accelerated by the expansion of Sgr A East into the 50 and the 70 \kms cloud and into the lobes of the CND.Comment: 31 pages plus 14 figures, ApJ (in press

The impact of a ward pharmacist in a surgical ward of a private hospital in the Eastern Cape

Medication errors are becoming problematic in both hospital and outpatient settings worldwide. Inappropriate use of medication can cause harm to the patient and maintaining high levels of quality patient care is essential to protect all patients. Clinical pharmacy practice contributes to improved patient care by optimising medication therapy; and promoting health, wellness and disease prevention. The involvement of a pharmacist at a ward level has been shown to improve patient care; reduce mortality and morbidity rates; decrease healthcare costs; minimise medication errors; and improve outcomes of drug therapy. However, clinical pharmacy is a fairly new practice in South Africa and there are limited studies available. This study aimed to evaluate the perceived benefits of a ward-based pharmacist on the provision of pharmaceutical care to patients in a hospital setting and to consequently implement a ward-based pharmacy service. The objectives of the study were: (1) to assess, via a questionnaire, the perceptions and attitudes of medical practitioners and nurses to ward-based pharmacy prior to and after implementation of a ward-based pharmacy service, (2) to implement a ward-based pharmacy service in a selected hospital ward; (3) to document and analyse the nature of the work and activities that a ward pharmacist undertakes, and (4) to document and analyse the frequency and nature of ward pharmacist interventions. The study was conducted in a surgical ward of a private hospital in the Eastern Cape. The study design was an intervention study, using a mixed-methods design, with a convergent approach. A convenience sample of 106 patients was obtained over the eight week study period. Participation was voluntary and confidentiality was maintained at all times. Four data collection tools were used during the study and a pilot study was conducted to ensure their validity and reliability. The quantitative data was analysed statistically while the qualitative questions were analysed through coding the various responses. The results of the study showed that medical practitioners and nurses of a surgical ward had a positive attitude towards ward pharmacy both prior to and after the implementation of a ward pharmacy service. There were ward pharmacist interventions made in 50% (n=106) of the patients who participated in the study. A large percentage (57%; 50; n=87) of the ward pharmacist interventions were pharmacist-initiated interventions to optimise patient care while prescribing errors (51%; 19; n=37) were the most commonly occurring medication error. The majority of the medication items involved in the interventions (34%; 34; n=101) were related to the anti-microbial medication class. Overall, there was a 73% (36; n=49) acceptance rate of the ward pharmacist interventions that were made to both the medical practitioners and nurses. There were a number of factors that had a significant relationship with a ward pharmacist intervention being required which included: (1) number of medication items (p=0.001; Chi² test; p<0.0005 Student’s t-test), (2) length of hospital stay (p<0.0005; Chi² test), (3) presence of one or more chronic disease states (p=0.003; Chi² test) and (4) presence of one or more allergies (p=0.028; Chi² test). The ward pharmacist interventions were shown to be of clinical significance and to have a positive impact on the patients concerned. It can be concluded that the ward pharmacy service was beneficial to the patients, medical practitioners and nursing staff

HST Paschen alpha and 1.9 micron imaging of Sgr A West

We present HST/NICMOS images at 0.2" resolution of the HI Paschen Alpha (PaA) emission line in a 70" x 90" region of the Galactic center centered on the non-thermal radio source Sgr A*. The majority of the emission arises from ionized gas in the mini-spiral in the central parsec. PaA emission is also seen from 26 stellar sources, presumably early-type stars with mass-loss winds. The new data reveal significant small-scale structure (<1"~0.04pc) in the ionized gas of the mini-spiral; low surface brightness emission features are also seen for the first time. Extinction, estimated from the ratio of observed PaA emission to 6-cm continuum emission, varies from 20 to 50 mag with a median Av=31.1 mag, in excellent agreement with earlier estimates for the stellar sources and indepedent measurements derived using H92alpha recombination line data. Large increases in extinction are seen along the periphery of the ionized gas, suggesting that the ionized gas is partially extincted by dust in the molecular clouds at the outside of the ionized regions. The small-scale, filamentary structures in the ionized gas have a free thermal expansion time of only ~ 3000 yrs; either magnetic fields or mass-loss winds from the hot emission line stars may contain the ionized filaments. For both the ionized gas and the stellar continuum, the centroids of the emission remain within ~+/- 1" from a radius of 2" out to 40", providing further evidence that Sgr A* is indeed at or extremely close to the dynamical center of the Galactic nucleus stellar distribution. The 1.9 micron surface brightness increases inwards to 0.9" and then decreases or levels off closer to Sgr A*, possibly indicating the core radius of the central stellar distribution or depletion of the late-type stars by stellar collisions near the central black hole.Comment: 43 pages, 15 figures, 2 tables; Accepted to ApJ (9/1/03 issue

Chronic acceleration studies - Physiological responses to artificial alterations in weight Progress report

Influence of chronic acceleration on energy metabolism of chickens and animals, as indicated by maintenance feed requiremen

Shocked molecular hydrogen towards the Tornado nebula

We present near-infrared and millimetre-line observations of the Tornado nebula (G357.7-0.1). We detected 2.12 micron_m H2 1-0 S(1) line emission towards the suspected site of interaction with a molecular cloud revealed by the presence of an OH(1720 MHz) maser. The distribution of the H2 emission is well correlated with the nonthermal radio continuum emission from the Tornado, and the velocity of the H2 emission spans over 100 km/s, which both imply that the H2 emission is shock excited. We also detected millimetre-lines from 12CO and 13CO transitions at the velocity of the maser, and mapped the distribution of the molecular cloud in a 2 x 2 arcmin^2 region around the maser. The peak of the molecular cloud aligns well with an indentation in the nebula's radio continuum distribution, suggesting that the nebula's shock is being decelerated at this location, which is consistent with the presence of the OH(1720 MHz) maser and shocked H2 emission at that location.Comment: 10 pages, 8 figures, minor changes, accepted to MNRA

Design data collection with Skylab/EREP microwave instrument S-193

There are no author-identified significant results in this report

Achieving doctorateness: Is South African higher education succeeding with graduate attributes?

This article applies findings from the recent national review of South African doctoral qualifications to examine ways in which universities interpret the formulation of, and apply in the context of a differentiated higher education system, the graduate attributes established in the qualification standard, in order to achieve the characteristics of “doctorateness”. The article explores the concept “graduate attributes” itself, the extent to which it is manifested in institutional, supervisory and examination practices, and how the concept is conveyed to and understood by students. National review findings indicate inconsistencies in conceptualisation and application both between and within institutions. In this article, emphasis is placed on the primary need of developing in the doctoral graduate the capacity to enter, as a deep-thinking researcher, into a community of practising peers, whether in the academy or in a profession

The role of syn-eruptive vesiculation on explosive basaltic activity at Mt. Etna, Italy

We investigated the dynamics of explosive activity at Mt. Etna between 31 August and 15 December 2006 by combining vesicle studies in the erupted products with measurements of the gas composition at the active, summit crater. The analysed scoria clasts present large, connected vesicles with complex shapes and smaller, isolated, spherical vesicles, the content of which increases in scoriae from the most explosive events. Gas geochemistry reports CO2/SO2 and SO2/HCl ratios supporting a deep-derived gas phase for fire-fountain activity. By integrating results from scoria vesiculation and gas analysis we find that the highest energy episodes of Mt. Etna activity in 2006 were driven by a previously accumulated CO2-rich gas phase but we highlight the lesser role of syn-eruptive vesicle nucleation driven by water exsolution during ascent. We conclude that syn-eruptive vesiculation is a common process in Etnean magmas that may promote a deeper conduit magma fragmentation and increase ash formation