Een en ander oor my ervaring in die Universiteit van Suid Afrika

Toe die Raad van die Universiteit van Suid-Afrika my teen die einde van 1944 uitgenooi het om ’n ondersoek in verband met die stelsel van eksterne studente aan die Universiteit in te stel, het ek reeds ’n redelike agtergronds kennis daarvan besit

Die pan-afrikanistiese vete teen Suid-Afrika

Die Pan-Afrikanisme het sy oorsprong onder die nako- melinge van die Negerslawe in die Wes-Indiese Eilande en die V.S.A. aan die begin van die huidige eeu. Aanvanklik was die hoofoogmerk die bestryding van diskrim inasie teen die Negers in Amerika en die sam esnoering van alle Negers in die wêreld in een beweging. Tydens en na die twee wêreldoorloë verskuif die sw aartepunt van die beweging na Afrika self en w ord dit die m ondstuk van die nuwe opkomende sw art nasio- nalisme wat veral gedra en gepropageer is deur ’n nuwe intellektuele elite opgelei in Europa en Amerika. Die hoof- doelstellings word van toe af die emansipasie en die eenheid van Afrika

Endovascular treatment of intractable epistaxis - results of a 4-year local audit

Objective. Transcatheter embolisation is an accepted and effective treatment for intractable epistaxis. We analysed our success and complication rates and compared these with results from other published series.Design. Retrospective review.Setting. Unitas Interventional Unit, Centurion.Methods. Case record review (57 procedures) and telephonic interviews (36 traceable respondents).Outcome measures. A numerical audit of the success and complication rates for embolisation procedures performed during the 4-year period between July 1999 and June 2003.Results. A total of 57 endovascular embolisation procedures were performed for intractable epistaxis in 51 patients during this period. Eight patients (15.7%) developed a re-bleed between 1 and 33 days after embolisation of whom 5 were re- embolised, giving a primary short-term success rate of 86.3% and secondary assisted success rate of 94.1%. Thirty-five of 36 respondents {97.2%) reported no further epistaxis during the long-term follow-up period of 1-47months. The mortality rate was 0%, the major morbidity rate was 2% (l stroke) and the minor morbidity rate was 25%.Conclusion. Our Success and complication rates are acceptable and compare favourably with those reported in other large series

European consensus on grading bone marrow fibrosis and assessment of cellularity

Quantification of characteristic bone marrow biopsy features includes basic parameters such as cellularity and fiber content. These are important to assess the dynamics of disease processes with a significant impact on risk stratification, survival patterns and, especially, therapy-related changes. A panel of experienced European pathologists and a foreign expert evaluated, at a multi-headed microscope, a large number of representative slides of trephine biopsies from patients with myelofibrosis in an attempt to reach a consensus on how to grade cellularity and fibrosis. This included a critical evaluation of previously described scoring systems. During the microscopic analysis and subsequent discussion and voting, the importance of age-dependent decrease in cellularity was recognized. Grading of myelofibrosis was simplified by using four easily reproducible categories including differentiation between reticulin and collagen. A consensus was reached that the density of fibers must be assessed in relation to the hematopoietic tissue. This feature is especially important in order to avoid a false impression of a reduced fiber content in fatty and/or edematous bone marrow samples after treatment. The consensus for measuring myelofibrosis by clear and reproducible guidelines achieved by our group should allow for precise grading during the disease process and after therapy

Progressive familial heart block type I : clinical and pathological observations

CITATION: 1991: .Van der Merwe, P.-L. et al. 1991. Progressive familial heart block type I : clinical and pathological observations. South African Medical Journal, 80:34-38.The original publication is available at http://www.samj.org.zaProgressive familial heart block type I (PFHB-I) is an autosomal inherited disease. It was previously postulated that the disease is limited to the cardiac conduction tissue. The presentation of a patient with dilated cardiomyopathy focused on the possibility that this might be part of PFHB-I. This observation led to routine echocardiographic examination of patients with complete heart block, who belonged to PFHB-I families, and another 5 cases with signs of dilated cardiomyopathy were identified. This is the first time, to our knowledge, that the histological picture of PFHB-I has been described. From these case reports it is clear that in the presence of a dilated cardiomyopathy the prognosis in PFHB-I tends to be poor.Publisher’s versio

Inferences from the kinematic properties of 6.7 GHz methanol masers

Context. It is now well established that the strong and widespread 6.7 GHz methanol masers are associated with young high mass stars. A still unsolved question is where in the circumstellar environment the masers arise. Aims.We address this question by considering an ensemble of rest frame maser velocities of 337 maser features. Methods. The CS(2-1) spectra of 63 methanol maser sources were used to derive systemic velocities and velocity dispersion of the thermal gas. Using the systemic velocities and the velocities of the 337 maser features in the 63 sources, a single distribution of rest frame maser velocities was constructed. This distribution as well as other kinematic information about the masers are used to evaluate four proposed scenarios for where the masers might arise in the circumstellar environment. Results.It is shown that kinematically the masers are not associated with hot cores. We also argue that the scenario in which the masers are associated with an external generated planar shock that propagates into a rotating core cannot explain the observed kinematic properties of the masers. It was found that a simple Keplerian-like disk model is consistent with the observed distribution of rest frame maser velocities. Although outflows have the potential to explain the data, it was not possible to fully test this possibility due to the diverse nature of outflows

VLA observations of water masers towards 6.7 GHz methanol maser sources

22 GHz water and 6.7 GHz methanol masers are usually thought as signposts of early stages of high-mass star formation but little is known about their associations and the physical environments they occur in. The aim was to obtain accurate positions and morphologies of the water maser emission and relate them to the methanol maser emission recently mapped with Very Long Baseline Interferometry. A sample of 31 methanol maser sources was searched for 22 GHz water masers using the VLA and observed in the 6.7 GHz methanol maser line with the 32 m Torun dish simultaneously. Water maser clusters were detected towards 27 sites finding 15 new sources. The detection rate of water maser emission associated with methanol sources was as high as 71%. In a large number of objects (18/21) the structure of water maser is well aligned with that of the extended emission at 4.5 $\mu$m confirming the origin of water emission from outflows. The sources with methanol emission with ring-like morphologies, which likely trace a circumstellar disk/torus, either do not show associated water masers or the distribution of water maser spots is orthogonal to the major axis of the ring. The two maser species are generally powered by the same high-mass young stellar object but probe different parts of its environment. The morphology of water and methanol maser emission in a minority of sources is consistent with a scenario that 6.7 GHz methanol masers trace a disc/torus around a protostar while the associated 22 GHz water masers arise in outflows. The majority of sources in which methanol maser emission is associated with the water maser appears to trace outflows. The two types of associations might be related to different evolutionary phases.Comment: accepted by Astronomy & Astrophysic

On the Identification of High Mass Star Forming Regions using IRAS: Contamination by Low-Mass Protostars

We present the results of a survey of a small sample (14) of low-mass protostars (L_IR < 10^3 Lsun) for 6.7 GHz methanol maser emission performed using the ATNF Parkes radio telescope. No new masers were discovered. We find that the lower luminosity limit for maser emission is near 10^3 Lsun, by comparison of the sources in our sample with previously detected methanol maser sources. We examine the IRAS properties of our sample and compare them with sources previously observed for methanol maser emission, almost all of which satisfy the Wood & Churchwell criterion for selecting candidate UCHII regions. We find that about half of our sample satisfy this criterion, and in addition almost all of this subgroup have integrated fluxes between 25 and 60 microns that are similar to sources with detectable methanol maser emission. By identifying a number of low-mass protostars in this work and from the literature that satisfy the Wood & Churchwell criterion for candidate UCHII regions, we show conclusively for the first time that the fainter flux end of their sample is contaminated by lower-mass non-ionizing sources, confirming the suggestion by van der Walt and Ramesh & Sridharan.Comment: 8 pages with 2 figures. Accepted by Ap