Stroke in the young

CITATION: De Villiers, R. V. P., February, E. & De Villiers, M. L. 2003. Stroke in the young. South African Medical Journal, 93(11):836-837.The original publication is available at http://www.samj.org.za[No abstract available]Publisher’s versio

Scattering of a Long Cosmic String by a Rotating Black Hole

The scattering of a straight, infinitely long string by a rotating black hole is considered. We assume that a string is moving with velocity v and that initially the string is parallel to the axis of rotation of the black hole. We demonstrate that as a result of scattering, the string is displaced in the direction perpendicular to the velocity by an amount kappa(v,b), where b is the impact parameter. The late-time solution is represented by a kink and anti-kink, propagating in opposite directions at the speed of light, and leaving behind them the string in a new ``phase''. We present the results of the numerical study of the string scattering and their comparison with the weak-field approximation, valid where the impact parameter is large, b/M >> 1, and also with the scattering by a non-rotating black hole which was studied in earlier works.Comment: 27 pages, 14 figures, to be published in Classical and Quantum Gravit

A near-infrared study of the star forming region RCW 34

We report the results of a near-infrared imaging study of a $7.8 \times 7.8$ arcmin$^2$ region centered on the 6.7 GHz methanol maser associated with the RCW 34 star forming region using the 1.4m IRSF telescope at Sutherland. A total of 1283 objects were detected simultaneously in J, H, and K for an exposure time of 10800 seconds. The J-H, H-K two-colour diagram revealed a strong concentration of more than 700 objects with colours similar to what is expected of reddened classical T Tauri stars. The distribution of the objects on the K {\it vs} J-K colour-magnitude diagram is also suggestive that a significant fraction of the 1283 objects is lower mass pre-main sequence stars. We also present the luminosity function for the subset of about 700 pre-main sequence stars and show that it suggests ongoing star formation activity for about $10^7$ years. An examination of the spatial distribution of the pre-main sequence stars shows that the fainter (older) part of the population is more dispersed over the observed region and the brighter (younger) subset is more concentrated around the position of the O8.5V star. This suggests that the physical effects of the O8.5V star and the two early B-type stars on the remainder of the cloud out of which they formed, could have played a role in the onset of the more recent episode of star formation in RCW 34.Comment: Accepted for publication in The Astronomical Journa

Factors Influencing the Development of Practical Skills of Interns Working in Regional Hospitals of the Western Cape Province of South Africa.

Background: Clinical skills and the ability to perform procedures is a vital part of general medicine. Teaching these skills to aspiring doctors is a complex task. It starts with a good theoretical preparation and some practical experience at university. On graduating from university, each doctor is faced with the task of transforming theoretical knowledge into the practical, procedural skills of a competent professional. This study aims to assess the perceptions of intern doctors working in regional hospitals in the Western Cape of their skills training both at undergraduate level and during the intern year. Methods: Focus groups involving 25 interns with 11 months' experience from five regional hospitals were used. Six themes were identified. These were undergraduate training, the student's attitude, the intern's approach to learning skills, opportunities for interns in regional hospitals, backup and support, and personal growth in procedural skills. Results: The majority of the participants found that their training at medical school prepared them adequately for the intern year. An obstacle to skills training at university was the structure of the teaching tertiary hospital, with its emphasis on rare diseases and lack of opportunities for hands-on experience. The amount of skills that were learned at university was related to the enthusiasm of the student. Once the student had qualified and was employed in a regional hospital, opportunities to learn skills were available in excess. The benefit of doing an internship in a regional hospital was described as a fine balance between opportunities, responsibilities and backup. In all the focus groups, the interns remarked on the high level of responsibilities that they had to bear, but this spurred them on in the learning of skills. The relationship between intern and senior doctor was important when it came to learning procedures. In most hospitals, the junior doctors perceived the backup cover available to them as adequate. Consensus existed as to the value of such an intern year and its importance in gaining procedural skills. At the start of the year, most interns experienced a lack of confidence, together with a sense of fear that they might not be adequately prepared to do the work expected of them. Confidence seemed to grow as the year progressed, and this was linked to experience and the successful completion of procedures, as well as adequate backup. It was found that, by the end of the year, graduates from different universities with varying emphasis on practical skills all performed at a similar level. Conclusion: The findings of this study affirm the literature in suggesting that skills training at university needs to be standardised by the introduction of a core curriculum in procedural skills. Learning outcomes should be fashioned around the relevant competencies required in the pre-registration year. It is vital for the training of new doctors that the internship year be optimised in terms of opportunities and backup as part of a strategy to improve skills training. The value of regional hospitals in teaching junior doctors clinical skills is emphasised. South African Family Practice Vol. 50 (1) 2008: pp. 70-70

A comparison of clinical communication skills between two groups of final-year medical students with different levels of communication skills training

Training in communication skills is prominent in many undergraduate medical programmes. In South Africa, training in this highly complex skill is developing rapidly, especially against the backdrop of a multilingual and multicultural society. Little work has been done locally to evaluate which training works best in our context. In 1999, the Stellenbosch University Faculty of Health Sciences introduced a new curriculum that included considerably more communication skills training. The aim of this study was to assess and compare the communication skills used in the consultations of two groups of final-year medical students who had different levels of communication skills training in order to make recommendations on appropriate changes in this training. Methods Standardised doctor-patient interviews performed by students during the final-year examinations in 2003 and 2004 were videotaped. These were assessed by two independent, blinded evaluators using an abbreviated version of the Calgary- Cambridge communication guide for skills not done (0) and done (1). The data was analysed using STATISTICA 7. Results A total of 161 interviews were analysed. Both groups performed well (mean = 1) in listening to the opening question, encouraging the patients to tell their story, and demonstrating appropriate non-verbal behaviour. However, ending the session by summarising and clarifying the plan was poorly performed (mean = 0.4). The 2004 group was statistically significantly better in structuring the consultation by using signposting (p value = 0.02). Conclusion There are a number of influences on the effectiveness of communication skills training, including issues around language, culture and gender, student attitudes, the significance of communication skills training in the programme and, most importantly, the integration of this training into the curriculum as a whole. Merely adding more time to communication skills training does not seem to be the answer. Incorporating a wider range of training methods is also important. The results of this impact study acted as an impetus for innovative curriculum development in our faculty, leading to the development of a comprehensive clinical model and a “golden thread” for communication skills in the curriculum to ensure the longitudinal integration of communication skills. South African Family Practice Vol. 49 (7) 2007: pp. 1

Highly syntenic and yet divergent: a tale of two Theilerias

The published genomic sequences of the two major host-transforming Theileria species of cattle represent a rich resource of information that has allowed novel bioinformatic and experimental studies into these important apicomplexan parasites. Since their publication in 2005, the genomes of T. annulata and T. parva have been utilised for a diverse range of applications, ranging from candidate antigen discovery to the identification of genetic markers for population analysis. This has led to advancements in the quest for a sub-unit vaccine, while providing a greater understanding of variation among parasite populations in the field. The unique ability of these Theileria species to induce host cell transformation is the subject of considerable scientific interest and the availability of full genomic sequences has provided new insights into this area of research. This article reviews the data underlying published comparative analyses, focussing on the general features of gene expression, the major Tpr/Tar multi-copy gene family and a re-examination of the predicted macroschizont secretome. Codon usage between the Theileria species is reviewed in detail, as this underpins ongoing comparative studies investigating selection at the intra- and inter-species level. The TashAT/TpshAT family of genes, conserved between T. annulata and T. parva, encodes products targeted to the host nucleus and has been implicated in contributing to the transformed bovine phenotype. Species-specific expansion and diversification at this critical locus is discussed with reference to the availability, in the near future, of genomic datasets which are based on non-transforming Theileria species

Thick domain walls around a black hole

We discuss the gravitationally interacting system of a thick domain wall and a black hole. We numerically solve the scalar field equation in the Schwarzschild spacetime and obtain a sequence of static axi-symmetric solutions representing thick domain walls. We find that, for the walls near the horizon, the Nambu--Goto approximation is no longer valid.Comment: 18 pages, 11 figures, one reference adde