145 research outputs found
Interpretatie van de door ir. H.C. Botma gebruikte methode ter bepaling van de verdeling van de kinetische golfenergie over richting en frequentie
No full textDe door Botma bepaalde richtingen (de richtingen van de snelheidsvectoren) komen met de golfcomponentrichtingen overeen indien er per frequentie slechts één richting voorkomt. In dat geval is het onderscheidend vermogen gelijk aan het gekozen richtingsinterval, afgezien van de meetfouten en de fouten t.g.v. de lengte van de meetlijnen. De door hem berekende energiedichtheid is in het algemeen niet te interpreteren als de kinetische energiedichtheid. In het algemene geval is de door hem berekende energiedichtheid moeilijk te interpreteren omdat de tijdvakken bekend zouden moeten zijn waarbinnen de richtingsvectoren in het betreffende richtingsinterval liggen. Bij het gebruikte rekenmodel zijn deze onbekend. Mogelijk kan m.b.v. simulatie een schatting van deze tijdvakken worden verkregen. Slechts in het geval dat er per frequentie slechts één richting voorkomt is de verdeling van de kinetische energiedichtheid berekend volgens de methode van Botma te interpreteren als het richtingsspectrum van de oppervlaktebeweging vermenigvuldigd met een responsiefactor en de verhouding tussen het richtingsinterval van de golfcomponenten en het gekozen richtingsinterval voor de snelheidsvectoren. Door de invloed van de eindige middelingsafstand zijn de uit de metingen van Goeree berekende richtingen niet gelijk aan de richting van de snelheden, uitgezonderd voor het geval dat de golfrichting gelijk is aan Pi/4 + n.Pi (n = 0, 1, ...) t.o.v. één der meetlijnen. Voor perioden> 6 sec is deze afwijking max. 2.5 %. De fout in de grootte van de snelheid voor perioden 6 sec is max 16.5 procent. De door Botma gebruikte methode is, omdat per frequentie meerdere richtingen kunnen voorkomen, niet geschikt voor het bepalen van het richtingsspectrum. Wel kan uit de snelheidsmetingen richtingsinformatie worden verkregen met behulp van een geparameteriseerde richtingsspreidingsfunctie. Hierbij verdient de in hoofdstuk VI van deze nota gedefinieerde richtingsspreidingsfunctie de voorkeur t.o.v. de andere in dit hoofdstuk genoemde functies, omdat: 1. direct de hoofdrichting en een maat voor de spreiding bekend is 2. stabiliteit van de beide te berekenen parameters groter is 3. het spectrum ook bepaald kan worden uit metingen waarbij alleen de horizontale snelheidscomponenten gemeten zijn.Hydraulic EngineeringCivil Engineering and Geoscience
Eosinophilic cystitis associated with Glanzmann's thromboasthenia : a case report
No full textCITATION: Botma, J. P., Burger, E. G. & De Kock, M. L. S. 1987. Eosinophilic cystitis associated with Glanzmann's thromboasthenia : a case report. South African Medical Journal, 71:533-534.The original publication is available at http://www.samj.org.zaEosinophilic cystitis is a rare condition, only 41 cases having been recorded in the literature. Glanzmann's thrombasthenia has been documented more than 100 times. The presence of these two conditions in one patient has, to our knowledge, not yet been reported in the English-language literature.Publisher’s versio
Hemifacial microsomia: progress in understanding the genetic basis of a complex malformation syndrome
No full text© Springer-Verlag 2001Hemifacial microsomia (HFM) is a common birth defect involving first and second branchial arch derivatives. The phenotype is extremely variable. In addition to craniofacial anomalies there may be cardiac, vertebral and central nervous system defects. The majority of cases are sporadic, but there is substantial evidence for genetic involvement in this condition, including rare familial cases that exhibit autosomal dominant inheritance. As an approach towards identifying molecular pathways involved in ear and facial development, we have ascertained both familial and sporadic cases of HFM. A genome wide search for linkage in two families with features of HFM was performed to identify the disease loci. In one family data were highly suggestive of linkage to a region of approximately 10.7 cM on chromosome 14q32, with a maximum multipoint lod score of 3.00 between microsatellite markers D14S987 and D14S65. This locus harbours the Goosecoid gene, an excellent candidate for HFM based on mouse expression and phenotype data. Coding region mutations were sought in the familial cases and in 120 sporadic cases, and gross rearrangements of the gene were excluded by Southern blotting. Evidence for genetic heterogeneity is provided by the second family, in which linkage was excluded from this region.D. Kelberman, J. Tyson, D. C. Chandler, A. M. McInerney, J. Slee, D. Albert, A. Aymat, M. Botma, M. Calvert, J. Goldblatt, E. A. Haan, N. G. Laing, J. Lim, S. Malcolm, S. L. Singer, R. M. Winter, M. Bitner-Glindzic
Race talk in the South African media
No full textCITATION: Botma, G. 2019. Race talk in the South African media. Stellenbosch: SUN PReSS, doi:10.18820/9781928480297.The original publication is available at https://africansunmedia.store.it.si/za"This book makes a very significant, timely and relevant contribution to a very topical subject of immense local as well as global interest. Through tracing the evolution of media discourse about race and racism, which the author prefers to call ‘race talk’, the writer prised open a window to a panoramic, variegated and yet nuanced perspective of the perennial South African race question etched across the vistas of time and memory since Jan Van Riebeeck set up the first European settlement as a refreshment station for the Dutch East India Company, at the Cape of Good Hope in 1652 up to the time of writing this book. It lends a fresh lens through which to re-read South African society, not only to a studious scholar of media history but also to anybody interested in the general history of South Africa.
- Dr Zvenyika Mugari, WITS
This book is based on meticulous archival searching, presented in a new, fresh and highly engaging way. This is a book based on evidentiary-led scholarly principles that has lucidity as a goal. Unlike so many scholarly works which are turgid and very difficult to read because they are written in restricted codes meant only for other academics, this manuscript is wonderfully lucid, accessible and a pleasure to read. The prime readership will be academics but its lucidity makes it appealing beyond a purely academic readership, hopefully reaching media professionals and students also and influencing debates on race policy. This is how academic books, in fact, should be written.
- Prof Keyan Tomaselli, University of Johannesburg
The author has embarked on a very difficult and complex task of understanding the race construct in the South African media context. This is a highly contested and contentious space in South Africa and it is particularly arduous for a “white, middle-class, middle-aged, Afrikaans male” to navigate this space. The author has however eloquently managed to pilot this fine line of controversy. He offers a balanced view of the belligerent debate without treading insensitively on the toes of protagonists and at the same time challenges prevailing views.
- André Rose, National Cancer Institute"Publisher's versio
Extra-adrenal phaeochromocytoma. A case report
No full textCITATION: Botma, J.P. & De Kock, M.L.S. 1986. Extra-adrenal phaeochromocytoma. A case report. South African Medical Journal, 69(1), 143-144.The original publication is available at http://www.samj.org.zaENGLISH ABSTRACT: A case of hypertension in a young woman caused by an extra-adrenal phaeochromocytoma (EAP) situated in the hilum of the left kidney is reported. Surgical removal of the EAP resulted in control of the patient's hypertension without further drug treatment. The clinical features, diagnostic work-up and management of EAP are briefly discussed.AFRIKAANSE OPSOMMING: Geen opsomming beskikbaarPublisher’s versio
Malignant fibrous histiocytoma of the spermatic cord: A case report
No full textCITATION: Botma, J.P., De Kock, M.L.S. & Laubscher, W.M. 1987. Malignant fibrous histiocytoma of the spermatic cord. A case report. S Afr Med J, 71(5):326.The original publication is available at http://www.samj.org.zaA case of malignant fibrous histiocytoma of the spermatic cord treated by primary local excision, followed 5 days later by radical inguinal orchidectomy and hemi-scrotectomy is reported. At 30 months' follow-up the patient is free from local recurrence.Publisher’s versio
Contributions to Workshop Eurobike in Helsinki
No full textIn this report three subjects relevant for the study of bicycle traffic are presented, giving the state of the art in The Netherlands. They were presented at a workshop of Eurobike, a consortium preparing to carry out practically oriented research about bicycle traffic in European urban areas. The general set-up of the National Travel Survey is described. This survey also includes trips made by bicycle. Some details are given about the size of the survey, the change in method to collect the data in 1985 and the response rate. The modal split as a function of trip distance and the distribution function for bicycle traffic are given as examples of results that can be derived from the survey. In the safety part statistics are given about the general fatality rate of cyclists and other modes of traffic. Two studies to determine criteria for the need for separate cycle paths are described. A study proposal for analysing safety and behaviour in tenns of risk for a mix of fast and slow traffic on an arterial is presented. The third subject is the cycle planning model Quo-Vadis that can be used to determine the best possible cycling network and the best allocation of the budget for bicycle facilities. A short description of the model and its required input is presented. The traffic model part can determine cycle intensities over the period 7 AM to 7 PM on every link of the network and the origins and destinations of the flow. The evaluation part can be used to evaluate an existing network and to assess the effect of measures improving the network. The combination of the model with accident data and the determination of yard-sticks for safety can give indications of how to improve safety.Transport and PlanningCivil Engineering and Geoscience
Implications of accreditation criteria when transforming a traditional nursing curriculum to a competency-based curriculum
No full textAbstractNurse educators in a resource-poor country have identified the need to change from content-driven curriculum to a competency-based curriculum. A rapid assessment was done to determine the standing of nursing education in the country. Structured interviews were conducted with educational and administrative staff as well as students at all six nursing schools in Lesotho. Programme design, human resources, teaching and learning, physical resources, and programme accreditation were addressed during the rapid assessment. The results were uniform due to the country being small and four nursing schools forming a consortium. A traditional content-driven three-year diploma programme that renders a single-qualified nurse is being offered. A five-year degree programme in nursing is being offered by the only university in the country. Nursing schools are resource-poor with limited or no external funding sources. Changing to and sustaining a competency-based curriculum will require extensive empowerment of nurse educators. Professional governing bodies should produce supporting rules and regulations
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