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

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

The poor children of the poor: Coping with diabetes control in a resource-poor setting

Background. Coping with diabetes control is difficult for newly diagnosed and experienced patients alike. Children with diabetes face severe challenges, as they may not yet have attained the necessary cognitive, fine motor or psychosocial skills required for performance of the tasks required from the diabetic patient. Most therefore require some adult assistance.Objectives. To establish whether paediatric diabetic patients are adequately supported by their families in terms of giving insulin injections and doing home blood glucose monitoring (HBGM), and whether insulin and the necessary equipment are appropriately stored in their homes.Methods. Patients attending a paediatric diabetes clinic were interviewed. The data collected included demographic variables, type of insulin, measurement of insulin doses, administration of insulin, and blood glucose monitoring tests.Results. Twenty-five subjects were interviewed: 18 measured the insulin themselves, five mothers and one aunt did so, and in one case the mother and patient did so together. The four children aged ≤10 years had their insulin measured by their mothers, but one had to administer the injection himself. Eight of the nine children aged 11 - 15 years measured and administered the insulin themselves; in four cases the doses were checked by an adult. The mothers of four children did the fingerpricks, and eight children were helped with measuring the results. Only two children aged 11 - 15 years had their doses checked by an adult.Conclusion. Adult assistance with regard to both insulin injections and HBGM is rarely forthcoming. The children seem not to besufficiently supported by their families

Sports imaging for the general practitioner

No Abstract

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

Predicting the Date of Bud Burst in Grapevines

It was possible to forecast the date of bud burst under South African winter temperatures (Region III) using the Pouget-formulae and principles, and to establish a scale of bud burst for cultivars grown in South Africa. The sum of daily temperature effects was higher under the warmer South African conditions which resulted in changes in the formulae for determining the daily effect of temperature and the cultivar coefficient on the bud burst date. Highly significant linear relationships were, however, obtained and it was possible to predict the date of bud burst fairly accurately

First-year Accounting students’ confidence levels during Covid-19: Evidence over a period of two years at a South African university

The Coronavirus Disease (Covid-19) outbreak has caused serious and continuous concerns globally within the higher education sector. One of these is the confidence levels of students to perform specific academic-related tasks. This study explored first-year accounting students’ confidence levels during Covid-19 over a two-year period at a South African university to determine if any associations exist between students’ gender, age, choice of study, language, and method of study funding, compared to confidence level, whilst applying a quantitative research design. Mixed results were obtained. Areas for further research identified include collaboration with other universities, and to expand the scope of the population, to determine the status of students’ confidence levels for different accountancy-related modules during and post-Covid-19. The study will inform and sensitise lecturers, students and academic institutions regarding the confidence levels of students to perform specific academic-related tasks within accounting education and training under Covid-19 conditions

Determining The Impact Of Capitalising Long-Term Operating Leases On The Financial Ratios Of The Top 40 JSE-Listed Companies

Operating leases forma great part of companies’ financing structures in today’s economicenvironment. Some accounting standard-setters and other users of financialstatements are of the opinion that the current standard on accounting foroperating leases, IAS 17, does not provide sufficient guidelines on the disclosureof a company’s leasing activities. The current accounting standard on leasesprovides companies with the opportunity to classify lease contracts intodifferent classes which leads to off-balance-sheet financing. This problem iscurrently being addressed by the IASB as they are in the process of developingan improved standard on leases. The main focus ofthis paper is to determine the impact of the improved accounting standard onthe financial statements and the resulting financial ratios of theJSE Top 40 companies when operating leases are accounted for ason-balance-sheet debt. The differences between the current IAS 17 and theExposure draft (ED/2010/9) are identified and the comparison indicatessignificant differences between these two approaches on accounting foroperating lease activities. The focus of the IASBin developing this exposure draft was to provide the users of financialstatements with a universal picture of the leasing activities that the companyis engaged in. The findings include that this objective is achieved as usersare not left uninformed about any of the financing activities that stakeholdersare exposed to if indeed a company is engaged in operating lease activities.The study also revealed that the capitalising of long-term operating leaseswill have a significant effect on the key financial ratios that stakeholdersuse to interpret a company’s financial performance