Criminology and Security Science / D. Litt. et Phil. (Criminology)

The Russian wheat aphid (RWA) (Diuraphis noxia Kurdjumov) is one of the important insect pests of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.) and other grasses. To date, there are four RWA biotypes identified in South Africa. The virulent biotypes emerged, partly due to climate change and new genetic variations within populations of RWA; hence there is a need to improve host-plant resistance, as an effective control measure. Bread wheat (Triticum aestivum L.) accession Cereal Introduction (CItr) 2401 is known to be resistant to all RWA biotypes worldwide. The goal of this study was to use a backcrossed near-isogenic line (NIL) BC5F5 mapping population, developed from a cross between CItr 2401 and susceptible Kavkaz, to identify and validate single nucleotide polymorphism (SNP) markers linked to the resistance phenotype in CItr 2401. This was achieved by (i) conducting a preliminary study that evaluated the suitability of simple sequence repeat (SSR) markers previously reported in literature for discriminating stacked RWA resistance genes and, (ii) employing SNP markers for the first time in a RWA resistance study as a future alternative to the widely used SSR markers. None of the tested SSR markers showed potential use in marker-assisted selection (MAS). The mapping population was phenotypically evaluated for RWA resistance using the four South African biotypes, viz. RWASA1, RWASA2, RWASA3 and RWASA4. Analysis of variance (ANOVA) showed significant (P<0.001) differences of genotypes after confirming the normality of residuals and homogeneity of variance. The Illumina iSelect 9,000 wheat SNP platform was used to genotype the two crossing parents and a selection of 24 NIL genotypes from the mapping population. Eight SNP markers found to be linked to the phenotype were converted to breeder-friendly and high-throughput Kompetitive allele-specific polymerase chain reaction (KASP) markers. The designed KASP markers were validated on the two crossing parents, the 24 NIL sent for SNP genotyping, on the mapping population and on the preliminary study genotypes for their effectiveness. The KASP assays developed in this study will be useful for stacking the RWA resistance from CItr 2401 with other Dn genes effective against the RWA. / Life and Consumer Sciences / M. Sc. (Life Sciences)

This study is concerned with what is happening within a mentorship interaction between engineers aimed at knowledge transfer. The practice of knowledge transfer is contextualised within the knowledge economy that ideologically positions Western economies as knowledge holders and advanced, while positioning developing countries as knowledge deficient and backwards. The prevailing literature regards knowledge transfer as difficult to achieve and is primarily focused on factors that hinder its success, looking to causal relational factors between and within the participants, in particular the qualities of knowledge receivers. Constructing the relationship and the individuals engaged in knowledge transfer as problematic brings about certain types of relations between individuals and between groups. These bring into play the positioning of role players within knowledge transfer that is not neutral, creating asymmetrical power relations and impacting identity construction. Studies in knowledge transfer have examined the factors that inhibit successful knowledge transfer extensively and do not consider its discursive context or considerations of power relations. Based on the assumption that discourse produces social practices and individual identities within social, historical and cultural contexts, this study adopted a social constructionist perspective and suggests that the ways in which identities are constructed in a mentorship interaction affect how participants experience and make sense of their worlds, which has implications for the practice of knowledge transfer. Viewing power as embedded in relations, a Foucauldian Discourse Analysis was conducted of discursive constructions generated from 17 interviews of participants engaged in a multinational knowledge transfer project between South African and Saudi Arabian engineers. The analysis showed that the construction of self and other does have an impact on knowledge transfer between Saudi Arabian and South African engineers. The multiple identity constructions of the participants within the knowledge transfer relationship were resourced from dominant discourses that reveal different meanings attributed to the participants’ mentorship experience and showed the systematic setting up of self and other within unequal power relations that favour the self. The study suggests that deeper consideration should be given to the effects of othering and power within social interactions between individuals located in divergent contexts such as those that characterise knowledge transfer. / Psychology / Ph. D. (Consulting Psychology)

MESMEG / Department of Mining and Environmental Geology / This study entails geochemical and mineralogical characterization of gold tailings of Nestor Mine and Glynn’s Lydenberg Mine of the Sabie-Pilgrim’s Rest goldfields. A total of 35 samples were collected and were analysed for chemical composition (XRF and ICP-MS), mineralogical composition (XRD). In addition, acid-base accounting (ABA) techniques had been conducted to predict the potential for acid mine drainage. Seepage from Nestor tailings dump and water samples from the adjacent Sabie River were also collected and analysed by means of inductively coupled plasma mass spectrometry (ICP-MS) and immediate constituent (IC) -analytical techniques. The study revealed that Sabie-pilgrim’s rest goldfield is characterized by both acid generating and non-acid producing tailings, and this is attributed to variations in the mineralogy of source rocks. Gold occurred within the Black Reef Quartzite Formation in the Nestor Mine and within the Malmani Dolomite in the case of Glynn’s Lydenburg Mine. Mineralogy and bulk geochemical analyses performed in this study showed a clear variation in the chemistry of Nestor Mine and Glynn’s Lydenburg Mine tailings. Predominant oxides in Nestor mine tailings samples are SiO2 (ranging from 66.7-91.25 wt. %; followed by Fe2O3 and Al2O3 (in range of 0.82-15.63 wt. %; 3.21-12.50 wt. % respectively); TiO2 (0.18-10.18 wt. %) and CaO (0.005-3.2 wt. %). Also occurring in small amounts is CaO (0.005-3.2 wt. %), K2O (0.51-2.27 wt. %), MgO (0.005-1.46 wt. %), P2O5 (0.029-0.248), Cr2O3 (0.013-0.042 wt. %) and Na2O (0.005-0.05 wt. %). The samples also contain significant concentrations of As (137-1599 ppm), Cu (34-571 ppm), Cr (43-273 ppm), Pb (12-276 ppm), Ni (16-157 ppm), V (29-255 ppm), and Zn 7-485 ppm). In the Glynn’s Lydenburg Mine tailings SiO2 is also the most dominant oxide ranging between 47.95 and 65.89 w%; followed by Al2O3 (4.31 to 16.19 wt. %), Fe2O3 (8.48 to 11.70 wt %), CaO (2.18 to 7.10 wt. %), MgO (2.74 to 4.7 wt. %). Occurring in small amounts is K2O (1.12-1.70 wt. %), MnO (0.089-0.175 wt. %), P2O5 (0.058-0.144 wt. %) and Cr2O3 (0.015-0.027 wt. %). Arsenic (As), is also occurring in significant amounts (807-2502 ppm), followed by Cr (117-238 ppm), Cu (10-104 ppm), V (56-235 ppm), Ni (45-132 ppm), Pb (13-63 ppm) and Zn (90-240 ppm). Nestor Mine tailings associated with Black Reef Formation mineralization have net neutralizing potential (NPR) <2, hence more likely to generate acid; and their acid potential (AP) ranges 1.56 to 140.31 CaCO3/ton and neutralizing potential (NP) range from -57.75 to -0.3 CaCO3/ton. Glynn’s Lydenburg Mine tailings dump which is vi associated with dolomite mineralization, however, was not leaching acid. Based on acid-base accounting results, these tailings have more neutralizing potential (ranging between 57.6 and 207.88 CaCO3/ton) than acid potential (ranging between 7.5 and 72.1 CaCO3/ton); and their NPR>2, hence unlikely to produce acid. This is confirmed by paste pH which was in the ranges between 7.35 and 8.17. Tailings eroded from Nestor Mine tailings dump were also found to be characterized by high content of metals and oxides, namely, As, Cu, Ni, Pb, V, and Zn with SiO2, Fe2O3 and TiO2. The tailings were observed eroded into the Sabie River where AMD related precipitate (yellow boy) was also observed, indicating further oxidation downstream. Field observations, onsite analyses of water samples and laboratory results revealed that Nestor Mine tailings storage facility discharges acid mine drainage with considerable amounts of Al, As, Cu, Fe, Mn, Zn and SO4 and very low pH exceeding the limit as per South African water quality standards. High concentrations of these metals have toxicity potential on plants, animals and humans. Upon exposure to oxygen and water, tailings from Nestor Mine are more likely to generate acid mine drainage that can cause detrimental effect to the environment and the surrounding communities. Potential pollutants are Fe, Mn, Al, As, Cr, Cu, Ni and Pb. Tailings from Glynn’s Lydenberg showed no potential for acid mine drainage formation. / NRF

In early 2003, a persistent drought threatened about 15 million people in the Southern African region (SADC) with starvation as farmers in this region were not able to produce enough food. A similar threat was experienced in the United States of America (USA). The Americans responded by introducing GM technology, which thankfully stabilised corn production and food security. It was against this backdrop that the South African government legalised and supported GM technology in the farming industry. However, the technology became a contentious issue amongst scholars, politicians and policy makers as well as farmers. Therefore, this study analysed the perceptions of small-scale and large-scale farmers, located in Paarl, Western Cape, South Africa, on the adoption of GM technology. This qualitative study, using a case study design, collected primary data from thirty (30) farmers: fifteen (15) small-scale and fifteen (15) large-scale farmers. The findings revealed complex factors influencing farmers’ adoption decisions and that Adopter perception (AP) and Consumer perception (CP) play a key role in their adoption of GM technology. These commercially and profit-driven farmers avoid using GM technology because public opinion and the markets weigh heavily against it. It was concluded that the farmers regarded GM technology as just one of many agricultural technologies and not as an exception. It was also considered unaffordable and detrimental to the environment, the economy and their livelihoods.The study recommends that the government should fully investigate public perceptions with regard to the adoption of any new agricultural innovation prior to making policy decisions. / Development Studies / M.A. (Development Studies)

MESMEG / Department of Mining and Environmental Geology / Although clay brick manufacturing has been going on for many years in South Africa, informal small-scale clay brick manufacturing enterprises are not officially regulated. Consequently, informal brick makers in the study area do not adhere to the demanding requirements of the South African National Standards for burnt clay masonry. Therefore, their clay bricks lack uniformity in terms of quality. Preliminary work revealed that over time, buildings constructed with these bricks develop cracks, thereby compromising safety. The importance of product quality management is not well understood in the informal brick manufacturing enterprises. As a result, they do not have any product quality management guidelines. The main purpose of this research was to develop the product quality management guidelines for ensuring quality in small-scale brick making enterprises in Dididi area. The specific objectives were to characterize the raw materials for clay brick manufacturing, identify and assess the technical problems of clay brick production, analyse the process of clay brick production and determine areas where product quality improvement is warranted. The research involved fieldwork which included soil sampling, analysis of clay brick production through the use of questionnaires and onsite observation of the production process, collection of samples of burnt bricks which were examined for compressive strength, water absorption as well as dimension measurements. These were then compared with the prescribed quality standards. Laboratory analyses of samples of raw materials were conducted and these included sieve analysis which was conducted in order to establish the particle size distribution of the raw materials; Atterberg limit tests were conducted in order to establish the physical characteristics of the soil. Chemical and mineralogical analyses were carried out to determine the chemical and mineralogical composition of the soil using XRF and XRD respectively. The textural characterisation of the material revealed abundance of sand sized particles and significantly low amounts of clay and silt. The plasticity of the soil used for bricks manufacturing in the study area was found to be ranging from slight to medium plasticity. Chemical analysis showed elevated silica contents with minor amounts of alumina and iron oxide. XRD analysis revealed the dominance of non-clay minerals with the highest concentration of quartz. The average compressive strengths of the tested brick samples for site A was 3.8, and 2.9 and 3.8 MPa for sites B and C respectively. The water absorption of the bricks was 13.5, 15.0 and 16.1% for samples from Site A, B and C respectively. The bricks dimensions met the recommended standards although their sizes were not uniform. v The survey conducted on brick manufacturing process revealed that the technical inefficiencies were mostly influenced by human and mechanical factors as well as the material inappropriateness. The production process was found to be too manual and labour intensive. Selection of the raw materials for brick manufacturing was based on indigenous knowledge and experience and most of the brick manufacturers lacked the prerequisite experience for making quality bricks. On the basis of the results of this research, it can be concluded that the materials used for manufacturing of clay bricks in Dididi are not well suited for making good quality bricks due to the reduced plasticity of the soil and the high concentration of quartz. These render the bricks brittle. It was also concluded that the production process also contributes to the poor quality of the bricks as the nature of the process was too manual. Selection of materials based merely on knowledge and experience and no scientific tests resulted in selection of inadequate materials which in turn affect the quality of the final bricks. It is therefore recommended that plastic clays be added to the raw clay materials to enhance its moulding property. In addition, materials such as internal fuels and anti-shrinkage materials should be incorporated into the process cycle to prevent cracking during drying and firing. Based on the findings of the analysis of the production process, it is recommended that mechanized techniques be employed in the operation and awareness training conducted to improve the understanding and skills of the brick manufacturers and to ensure production of good quality bricks. / NRF

Text in English / South Africa is one of the biggest producers of genetically modified crops in the world. However, recent studies in South Africa show a low public willingness to consume genetically modified crops and accept modern agricultural biotechnology. The study analysed public perception towards consuming genetically modified crops and the acceptance of modern agricultural biotechnology in South Africa. 220 participants (N = 220) were sampled from the city of Kempton Park and the Chi-square formula was used to determine how well the sample represented the population under study. Data was collected using a 7-point Likert scale questionnaire designed following the guidelines for developing a theory of planned behaviour questionnaire in Ajzen (1991, 2001). Data analyses were carried out using the Statistical Package for Social Sciences (SPSS). The Cronbach’s alpha and Exploratory Factor Analysis were both used to determine the internal consistency and validity of the questionnaire. Correlations, independent sample t-tests, ANOVA, linear regression, and path analysis were also conducted. Findings of the study confirmed that there is low public willingness to consume genetically modified crops and to accept modern agricultural biotechnology in South Africa. / Development Studies / M.A. (Development Studies)