702 research outputs found
BOTHA, Anna Elizabeth Inventory of documents
No full textCOVERAGE 1935-1976; 52 Files; 37,80 Metres.Private papers of A.E. Botha, wife of State President P.W. Botha
Fast developing Russian wheat aphid biotypes remains an unsolved enigma
No full textCITATION: Botha, Anna-Maria. 2021. Fast developing Russian wheat aphid biotypes remains an unsolved enigma. Current Opinion in Insect Science 45(2021):11 pages. doi.10.1016/j.cois.2020.12.001The original publication is available at: sciencedirect.comDiuraphis noxia, commonly known as the Russian wheat aphid, is an economically important cereal pest species, highly invasive and reproduces mostly asexually. Remarkably, many new virulent populations continue to develop, despite the lack of genetic diversity in the aphid. Russian wheat aphid is a phloem feeder and is therefore engaged in a continuous arms battle with its cereal host, with the acquisition of virulence central to the breakdown of host resistance. In the review, most attention is given to recent topics about mechanisms and strategies whereby the aphid acquires virulence against its host, with special reference given to the role of noncoding RNA elements, bacteria, and the epigenetic pathway in possibly directing virulence.Publisher’s versio
Appel Botha Cornelitz : the abc of a three hundred year old divorce case
No full textIn 1683 Maria Kickers and Jan Cornelitz got married in Cape Town. Today, 330 years later, the living
patrilineal descendants of Maria’s four sons, number in excess of 76,000 people. Curiously, none of them
carry the surname Cornelitz – in fact, they are all called Botha and include former President P.W. Botha,
general Louis Botha and Minister Pik Botha. The reason for this anomaly is also the reason why Jan got
divorced from Maria in 1700. According to Maria’s testimonies she did indeed have a long term
relationship with Frederik Botha, but in her defence she claimed that her husband was impotent and that
he actually encouraged her. Other witnesses, presumably prompted by Jan, gave testimonies that
implied that Maria was in fact licentious. We combined haplotyping with the AmpF‘STR1 YfilerTM kit
with deep-rooting genealogies to show that Maria’s first son was actually fathered by Ferdinandus Appel
and that roughly half the living Bothas (38,000 people) actually descend from Ferdinandus Appel while
the remaining three sons all stem from the same father, presumably Frederik Botha, and this implies that
Maria’s husband did not father any of her sons.This work was supported by Grant 77256 from the National Research Foundation to JMG.http://www .elsevier.com /locate/fsighb201
CONSIDERATIONS REGARDING AN INTEGRATED UNIVERSITY MANAGEMENT SYSTEM
No full textToday we witness an increase in the role of universities in civil society. The international trends show the universities’ openness towards the alternative offered by new technologies. The article shows the actual perspectives in our country, presents the main characteristics and the structure of a computerized university management system, and also indicates the possibility of informatic integration for the system modules. The development of such a project must be controlled and validated by a standardized methodology for project management, which is shown in the article.Project Management, informatic system, management of an educational institution, portal application integration, methodology, Prince2
Assessing the cyto-genotoxic impacts of un-neutralised and pH-neutralised acid mine drainage on the human breast cancer cell line, MCF-7
No full textThesis (MSc)--Stellenbosch University, 2015.ENGLISH ABSTRACT: The use of toxicity tests to evaluate the quality of streams affected by mixtures such as acid mine drainage (AMD), adds value to assessments whereby site-specific toxicological data may identify toxicants that pose a threat to humans. To successfully evaluate the risk of combined mixtures, an improved understanding of the individual components, their uptake, metabolism, excretion and mode of action is required. This study aimed to identify the extent of AMD toxicity in a dose dependant manner on the MCF-7 cell line. The first study site associated with gold mining was chosen as the Tweelopies Stream situated in the Gauteng province of South Africa. The AMD effluent (un-neutralised) contaminating the Tweelopies Stream had undergone pH-neutralisation using a reactor-bed limestone technology incorporating the use of both calcium carbonate (CaCO3) powder and limestone beds. The second study site, the Kromdraai River, is situated in the eMalahleni region of South Africa where a predominance of coal mining exists. The pH -neutralisation of the AMD (un-neutralised) contaminated Kromdraai River was performed using a caustic soda (NaOH) precipitation technique. This study demonstrated the rapid and effective application of the comet assay as a screening tool for AMD-associated DNA breakages in the human cell line, MCF-7. Moreover, the study analysed parameters of cellular survival, DNA fragmentation and variations in morphologies indicative of cellular death. Collectively, the cyto-genetic aberrations observed in the MCF-7 cells as a result of exposure to gold and coal mining associated AMD, confirms the urgency of incorporating high-throughput screening in ecological toxicity assessment to evaluate cellular damage at genetic levels in low dose exposures where detection might be missed.AFRIKAANSE OPSOMMING: Die gebruik van toksisiteitstoetse om die gehalte van strome te evalueer wat geraak word deur mengsels soos suur mynwater (SM), gee waarde aan spesifieke toksikologiese data van gifstowwe wat 'n bedreiging vir die mens kan identifiseer. Om die risiko van gekombineerde mengsels en hul individuele komponente beter te begrip en suksesvol evalueer, is hul opname, metabolisme, uitskeiding en modus van aksie nodig. Hierdie studie het gepoog om die omvang van SM-toksisiteit in 'n dosis afhanklike wyse op die MCF-7-sellyn te identifiseer. Die eerste studie-area wat gekies is, hou verband met goudmyn-ontginning, en is die Tweelopiesspruit, geleë in die Gauteng-provinsie van Suid-Afrika. Die SM-uitvloeisel (on-geneutraliseerde) wat die Tweelopiesspruit besoedel, het pH-neutralisasie ondergaan met behulp van die integrasie van 'n reaktor-bed kalksorpsietegnologie wat gebruik maak van beide kalsiumkarbonaat (CaCO3) poeier en kalksteenbeddens. Die tweede studie-area, is die Kromdraairivier geleë in die eMalahleni-streek van Suid-Afrika, waar steenkoolontginning die oorheersende aktiwiteit is. Die pH-neutralisasie van die SM (on-geneutraliseerde) in die geval van die Kromdraairivier word met behulp van 'n bytsoda (NaOH) neerslag tegniek, uitgevoer. Hierdie studie het die komeet-toets getoon as 'n vinnige en doeltreffende toepassing vir SM-geassosieerde DNA-breekskade in die menslike sel lyn, MCF-7. Verder het die studie parameters van sellulêre oorlewing, DNA-fragmentasie en variasies in sel morfologieë wat ‘n aanduiding van sellulêre dood is, ontleed. Gesamentlik dui die resultate daarop dat die sitogenetiese afwykings wat in die MCF-7-selle waargeneem is, as 'n gevolg van blootstelling aan goud- en steenkool-geassosieerde SM is. Die studie het verder die dringendheid van die integrasie van hoë-deurset tegnologieë in ekologiese toksisiteitstoetse in selle wat genetiese skade mag ondergaan, na 'n lae dosis blootstelling waar opsporing dalk gemis word, ondersteun.Master
Extreme ultraviolet emission lines of Ni xii in laboratory and solar spectra
No full textA linear force-free field solution is presented in cylindrical coordinates, formulated in terms of trigonometric and Bessel functions. A numerical exploration has revealed that this solution describes magnetic field lines that meander in Cartesian space, as well as field lines that lie on toroidal flux surfaces. These tori are in (or close to) the plane perpendicular to the cylindrical axis. Nested tori, as well as tori with shells that have finite thickness, were found. The parameter space of the solution shows that the tori exist within a bounded range of values
Failed states, fading dreams and a failing democracy : the critical role of public law academics
No full textText of inaugural address by Prof. Christoffel Botha, Department of Public Law on 17 October 2007.With reference to incidents where rule of law has been disregarded by the South African government and pointing to the danger of paraliament becoming a mere rubber stamp for the executive, the author urges legal academics - and particularly public law academics - to become involved through criticism
The Representation of Gays and Lesbians in South African Cinema 1985–2013
No full textTHE REPRESENTATION OF GAYS AND LESBIANS IN SOUTH AFRICAN CINEMA 1895-2013 Despite South Africa\u27s progressive constitution which prohibits discrimination against gays and lesbians, as well as a strong gay movement, South African cinematic images of gay men and women are limited and still at the margin of the South African film industry. One ends up with less than 20 short films, a few documentaries and less than 10 features with openly gay and lesbian characters in the past 114 years of South African cinema. Under apartheid, gay and lesbian voices in film and television were silenced. In a 20-year study of the representation of gays and lesbians in African, Asian and Latin American cinema (Botha 2003; 2012; Botha & Swinnen 2010), the author has noted that homosexual experience is unique in South Africa, precisely because of South Africa\u27s history of racial division and subsequent resistance. South African gay identities..
Numerical simulations of rotating axisymmetric sunspots
No full textA numerical model of axisymmetric convection in the presence of a vertical magnetic flux bundle and rotation about the axis is presented. The model contains a compressible plasma described by the non-linear MHD equations, with density and temperature gradients simulating the upper layer of the Sun's convection zone. The solutions exhibit a central magnetic flux tube in a cylindrical numerical domain, with convection cells forming collar flows around the tube. When the numerical domain is rotated with a constant angular velocity, the plasma forms a Rankine vortex, with the plasma rotating as a rigid body where the magnetic field is strong, as in the flux tube, while experiencing sheared azimuthal flow in the surrounding convection cells, forming a free vortex. As a result, the azimuthal velocity component has its maximum value close to the outer edge of the flux tube. The azimuthal flow inside the magnetic flux tube and the vortex flow is prograde relative to the rotating cylindrical reference frame. A retrograde flow appears at the outer wall. The most significant convection cell outside the flux tube is the location for the maximum value of the azimuthal magnetic field component. The azimuthal flow and magnetic structure are not generated spontaneously, but decay exponentially in the absence of any imposed rotation of the cylindrical domain
The Constitutionality of the Prohibition of Hate Speech in terms of Section 10(1) of the Equality Act: A Reply to Botha and Govindjee
No full textThis is a reply to a critique by Botha and Govindjee (2017 PELJ 1-32) of our interpretation of the hate speech provisions of the Equality Act (Promotion of Equality and Prevention of Unfair Discrimination Act 4 of 2000) in Marais and Pretorius (2015 PELJ 901-942), in which we considered the constitutionality of section 10(1) of the Act, amongst other things. We address Botha and Govindjees' rejection of our view that hate speech is a form of unfair discrimination and that the most appropriate constitutional framework within which section 10(1) should be interpreted and assessed is sections 9 and 10 of the Constitution. We consider Botha and Govindjees' rejection of this point of departure, their opposing different interpretation of the role of the proviso in section 12 of the Act and, generally, their reasons for concluding that section 10(1) is unconstitutional. We maintain that Botha and Govindjee's proposals for reform unduly restrict the hate speech prohibition to cover exclusively expression that warrants criminalisation. In doing so, they fail to fully acknowledge the transformative obligation in terms of international law, the Constitution and the Equality Act, to prohibit and prevent unfair discrimination
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