Generation IV high temperature nuclear reactors use TRISO (tristructural isotropic) particles for containment of radioactive fission products. In these particles silicon carbide (SiC) is the main barrier for containing solid fission products. ZrC has been proposed either as an additional layer or replacement of SiC layer of the TRISO fuel particle. This is because ZrC would be a better barrier than SiC against the diffusion of Ag and will be more resistant against palladium attack. This suggestion is based on ZrC‘s excellent physical properties like: low neutron capture cross section, good thermal shock resistance, excellent thermal stability, etc. However these properties depend on a number of factors such as chemical composition, microstructure, morphology, the presence of impurities, etc. Many attempts have been made to grow ZrC layers. However, the growth of high quality polycrystalline ZrC layers with good stoichiometry has remained a challenge. This study focuses on designing a chemical vapour deposition (CVD) reactor for growing ZrC layers and studying the properties of ZrC layers grown under different conditions. CVD was chosen as the most effective process to grow ZrC layers. CVD enables the production of relatively pure uniform layers with good adhesion and reproducibility at fairly good deposition rates. A thermal CVD reactor system operating at atmospheric pressure was designed to grow ZrC layers. Radio frequency (RF) induction heating was used as the energy source, with a vertical-flow design, using thermally stable materials. The ZrC layers were grown while varying the substrate temperature, gas flow ratios, substrate-gas inlet gaps, deposition time and partial pressures. The precursors utilised to grow ZrC were zirconium tetrachloride (ZrCl4) and methane (CH4) in an excess of argon and hydrogen. The deposited ZrC layers were then characterised by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), Raman spectroscopy and field emission scanning electron microscopy (FE-SEM). To optimise the process parameters, response surface methodology was applied. A central composite design was used to investigate the effect of temperature (1200 °C–1600 °C) and molar ratio of CH4/ZrCl4 (6.04–24.44) on the growth rate, atomic ratio of C/Zr and crystallite size of ZrC layers. The temperature of 1353.3 °C and the CH4/ZrCl4 molar ratio of 10.41 were determined as the optimal conditions for growing near-stoichiometric ZrC layers. The optimum values for C/Zr atomic percentage ratio, growth rate and average crystallite size were 1.03, 6.05 ?m/h and 29.8 nm respectively. The influence of the gap between the gas inlet and the substrate (70–170 mm) on the growth rate, surface morphology, phase composition and microstructure of ZrC layers deposited at different temperatures was investigated. The growth rate of ZrC layers prepared at 1400 °C was higher than at 1200 °C, and decreased with increase in the gap at both temperatures. The boundary layer thickness increased with an increase in substrate-inlet gap. The diffusion coefficients of the reactants increased with temperature. A model was used to illustrate the diffusion of source materials through the boundary layer to the reacting surface. An increase in the gap from 70 mm to 170 mm at a temperature of 1400 °C, caused the layers to become more uniform. An increase in particle agglomeration was also observed. By contrast, at 1200 °C the surface crystallites had complex facets that decreased in size as the gap increased from 70 mm to 170 mm. / Thesis (PhD)--University of Pretoria, 2017. / Physics / PhD / Unrestricted

The Western Cape Province is currently faced with population growth, declining household sizes, increasing household numbers, high levels of migration, urbanization and escalating development pressures. These factors have consequently triggered changes in land use and land cover (LULC) and incited issues such as urban sprawl, marginalization of the poor, limited public access to resources, land degradation and climate change. Furthermore, the issues surrounding LULC in the Province emanate from past inequities in access to land coupled with unsustainable land use practices. This poses a challenge to the government which strives for a sustainable nation that safeguards democracy by providing basic access to services, managing limited resources and advancing effective and efficient integrated planning whilst maintaining ecosystem functions. Understanding drivers of LULC change and how various factors influence LULC is important in meeting this challenge. Models which integrate and evaluate diverse factors of LULC change can be used to guide planners in making more informed decisions and achieving a balance between urban growth and preservation of the natural environment. The implementation of these models at a regional scale is however very limited in South Africa. LULC change models are valuable if their structures are based on deep knowledge of the system under investigation and if they produce credible results. This study therefore investigates the suitability of LULC change models in simulating LULC changes at a regional scale by quantifying changes in LULC in the Western Cape Province, determining the driving factors of LULC changes and exploring and implementing a regional land use change model. An investigation of changes in LULC was conducted by integration of a desktop study of LULC maps using the 1990 and 2013-2014 South African National LULC datasets; document analysis; and expert opinion in the form of semi-structured interviews with municipality town planners. An adapted Driver-Pressure-State-Impact-Response (DPSIR) Framework was used to analyse and present LULC changes in the study area. A literature review was conducted in shortlisting of models and further evaluations involved analysis of the models using selection criteria which focused on the model’s relevance to the study area, linkage potential to other models or software, transferability, user friendliness, data requirements and cost. The results of this study show that LULC changes in the Western Cape Province are driven by political, economic, technological, demographic, environmental and cultural factors which must be considered in strategies and policies in future planning to avoid detrimental impacts on the environment whilst maintaining socio-economic benefits. These factors were integrated in a hybrid model that was successfully implemented in the study area by combining Dyna-CLUE and Markov concepts. The hybrid model produced probability maps and simulation maps for the years between 1990 and 2014. Validation of the simulated maps was conducted using both visual and statistical analysis and the results indicated that the simulated maps were in good agreement with the validation map. Data availability was observed as the main drawback which influenced both the implementation of other suitable models and the accuracy of simulated maps. This study however contributes to the understanding of driving factors of LULC change and implementation of LULC change models at a regional scale in the South African context. Knowledge derived from this study can be used by planners as a guide to effectively gauge the impacts that planning policies and other driving factors might have on future LULC patterns in the Western Cape Province. / Dissertation (MSc)--University of Pretoria, 2018. / Geography, Geoinformatics and Meteorology / MSc / Unrestricted

The most prevalent micronutrient deficiencies in sub-Saharan Africa are iron, zinc and vitamin A. This is partly due to staple diets composed of mainly cereals, containing high levels of iron and zinc bioavailability inhibitors. In this study, pearl millet porridge was food-to-food fortified with dried micronutrient-rich plant foodstuffs (moringa leaves, hibiscus calyces, baobab fruit pulp), and a mango-carrot premix (plus sunflower oil) as a provitamin A source, and the effect on iron and zinc bioaccessibilities evaluated. The foodstuffs were analysed for mineral and antinutrient contents. The effects of adding 5 and 15 g/100 g, dry basis (db) pearl millet plus provitamin A source of dried moringa leaves, hibiscus calyces or baobab fruit pulp on iron and zinc bioaccessibilities (in vitro dialysability assay) were determined. Baobab fruit pulp, despite containing high levels of tannins (2286 mg CE/100 g, db), increased the iron and zinc bioaccessibilities the most, when added as food-to-food fortificants to pearl millet. This could contribute >200% and >180%, respectively, more to the iron and zinc absolute requirements (defined as the sum of the daily basal losses of the mineral plus the amounts of the mineral needed for growth) than the pearl millet plus provitamin A source porridge, for 2–5-year-old children. Fortification with hibiscus calyces also resulted in substantial increases in iron and zinc bioaccessibilities. This is because baobab fruit pulp and hibiscus calyces contain substantial levels of iron and zinc bioavailability enhancing organic acids. The addition of moringa leaves generally resulted in the lowest increases and, in some cases, even reduced the iron and zinc bioaccessibilities, even though it had the highest level of iron (58.4 mg/100 g, db) of all the plant foodstuffs. Dried moringa leaves had the highest levels of calcium and total phenolics, and substantial levels of phytate, as well as possible low levels of organic acids, all which contributed to the low iron and zinc bioaccessibilities. Including baobab fruit pulp and possibly hibiscus calyces in a cereal based meal, show potential to increase both the iron and zinc bioaccessibilities. The iron and zinc status of people consuming a cereal-based diet may be improved by the inclusion of baobab fruit pulp or possibly hibiscus calyces, as food-to-food fortificants, to cereal-based porridges. / Dissertation (MSc)--University of Pretoria, 2017. / Food Science / MSc / Unrestricted

The hybrid combination between Eucalyptus grandis and Eucalyptus urophylla plays a significant role in the production of pulp in the South African Forestry Industry. Superior clones of this hybrid combination have been bred using a conventional hybrid breeding strategy and planted successfully in the subtropical coastal region of South Africa, namely Zululand. Although the conventional hybrid breeding strategy of these species has delivered superior clones for commercial production, it is a time consuming strategy to follow. One of the constraints with the conventional hybrid breeding strategy is the time required to first test the hybrid material as seedlings before clonal testing commence. In order to address this, an accelerated version of the conventional hybrid breeding strategy is being investigated with the main focus on reducing the testing time of E. grandis × E. urophylla hybrid material as seedlings. With this in mind, this study was set out with two main aims, firstly to review the conventional hybrid breeding strategy, and secondly to do a comparative study between the conventional hybrid breeding strategy and the accelerated hybrid breeding strategy. In order to review the conventional hybrid breeding strategy, as well as to identify the impact of accelerating this strategy has, information on the genetic control of the traits of interest is needed for the E. grandis and E. urophylla pure species populations, as well as hybrid seedling and clonal populations. Additional information such as the correlation between parents’ performance in pure species and hybrid combination, as well as the ortet-ramet correlation of the hybrids is also essential for developing an effective hybrid breeding strategy. The main objectives of this study were, therefore, to first estimate the genetic parameters and indentify selections of E. grandis and E. urophylla pure species populations in Zululand; secondly to estimate genetic parameters of E. grandis × E. urophylla hybrid seedling and clonal populations; thirdly to investigate the correlation between E. grandis and E. urophylla parental General Combining Ability (GCA) and their General Hybridising Ability (GHA); fourthly to determine the correlation between E. grandis × E. urophylla hybrid seedling ortets and their ramets and lastly to do a comparative study between the conventional hybrid breeding strategy and the accelerated version of this strategy. Results of the E. grandis and E. urophylla pure species populations indicated that genotype by environment interaction (G×E) effects were present, but would be practically negligible for growth in Zululand and a single breeding population will therefore be appropriate. In general, volume was under low to moderate genetic control, with narrow-sense heritabilities ranging between 0.14 and 0.48 for E. urophylla, and between 0.16 and 0.23 for E. grandis. Best linear unbiased predictor (BLUP) estimates indicated that elite selections could produce genetic gains of approximately 60% and 30% over the E. urophylla and E. grandis population means respectively. With regards to the E. grandis × E. urophylla hybrid populations, results indicated that non-additive genetic variation explained the majority of the total genetic variation and ranged between 68% (seedling population) and 88% (clonal population from accelerated strategy). For the E. grandis × E. urophylla seedling population, most of the additive genetic variance was contributed by the E. urophylla parents (h2male = 0.23) and a correlation of 0.58 (p<0.007) was detected between the GCA and GHA values of the E. urophylla parents. However, for the E. grandis × E. urophylla clonal populations, narrow-sense heritabilties were low and ranged between zero (female) and 0.08 (male). Majority of the non-additive genetic variation was explained by the proportion of dominance variance ( =0.16), and less by the clone within family effect ( =0.12). Accelerating the conventional hybrid breeding strategy by shortening the testing time of E. grandis × E. urophylla seedlings resulted in an increase in percentage realised volume gains per year (from 1.9% to 3.7%) when compared to the E. grandis × E. urophylla commercial clone. / Thesis (PhD)--University of Pretoria, 2017. / Plant Production and Soil Science / PhD / Unrestricted

Globally, over the last 30 years, there has been an increase in the number of reports of tree mortality related to anthropogenically driven climate change. Changes in climate not only directly affect plant and tree growth but also influence insects and microbes (pests and pathogens) that interact with plants. Increased temperatures have, for example, led to an explosion in mountain pine beetle (Dendroctonus ponderosae) populations resulting in the death of more than 10 million hectares of Pinus contorta in Canada and the United States of America. This review considers the known and predicted impact of anthropogenic climate change on insects and pathogens in forest environments where large scale tree die-offs have been experienced. Most of these reports are from the Northern Hemisphere, but there are also instances in the Southern Hemisphere, including South Africa where tree die-offs are occurring and where climate is believed to play a role. For example, Euphorbia ingens trees in South Africa have been reported to be dying-off in unprecedented numbers. In this case, it has been suggested that opportunistic pests and pathogens, driven by changes in climate, may be contributing to the death of these trees. Climate change associated tree die-offs are not only of concern in the natural forest environment but are also important in planted forests where commercial impacts are relevant. Overall, climate change has become an important issue relating to tree diseases and it must be taken into consideration when investigating the factors involved in unexpected tree die-offs. / Thesis (PhD)--University of Pretoria, 2018. / Microbiology and Plant Pathology / PhD / Unrestricted

This study formed part of a greater departmental research project on methane mitigation strategies in livestock, fed poor quality feeds or kept under extensive grazing conditions. Globally, livestock represents a large source of methane (CH4) from anthropogenic activities, mostly from enteric fermentation by ruminants. The aim of this project was to study the effects of dietary methane mitigation interventions on growth and carcass characteristics, due to changes in the composition of adipose tissues in livestock. Feasible methane mitigation technologies can only be adopted once the effect on the entire production cycle has been evaluated, including the potential adverse effects of such technologies on product composition and quality. Although previous research has focused on the manipulation of carcass composition by dietary oil and fat supplementation, the novelty of the present study is to investigate the possible consequences of supplementing fibrolytic enzymes and palm oil on the fatty acid composition and the related effects on carcass and meat quality of livestock. In this study 40 South African Mutton Merino (SAMM) ram lambs were stratified according to their initial body weight and randomly assigned to one of the following four treatment groups with ten lambs as a sampling unit for each treatment. The lambs were fed high-forage based total mixed rations (TMR) that consisted of a TMR diet supplemented with Megalac as bypass oil (C); TMR supplemented with 3% palm oil (PO); TMR with cellulase and xylanase enzymes (1:1) (ET) and TMR supplemented with 3% palm oil and cellulase and xylanase enzyme (O*E), for approximately 120 days. After approximately 100 days and target weight of ca. 42kg, all lambs were slaughtered at a commercial abattoir, carcasses were electrically stimulated (21V, 60Hz, 120s) and chilled at 4?C for 24 hours. Hot carcass weight (HCW), cold carcass weight (CCW) and pH of carcasses were recorded, followed by collection of three rib-cut samples to determine carcass composition and fatty acid profiles of subcutaneous and intramuscular adipose tissue. Lambs fed treatment ET and C gained 20g more per day than those in the PO and O*E treatments. Lambs in treatment PO took 8 days longer to reach target slaughter weight. HCW and CCW were higher in treatments C and ET than in treatments PO and O*E. The average HCW 19.24±1.5kg was within the industry norm. Dressing percentages in this study were in line with industry averages of 45%, even though treatments PO and O*E had a ± 3% lower dressing percentage compared to other treatment groups. Supplementation of palm oil increased meat % of carcass composition by more than 4%. A lower percentage carcass fat was observed in treatment PO and O*E. The proportion of fatty acids from this study was similar across all four treatments groups; numerically these values were so small, even negligible in some cases. Interaction effects were detected between oil and enzyme treatments for SFA’s, MUFA’s and the UFA’s in subcutaneous adipose tissue. Oil treatment groups in the present study differed from the other treatment groups and generally reduced the PUFA concentration. Palm oil supplementation affected the subcutaneous fatty acid profiles of lambs, which include C14:0, C16:0, C17:0, C18:0, C18:2n6c, C20:3n6 and C20:4n6. A general decrease in SFA concentration was observed for oil treatments in all of the SFA where oil supplementation had a significant effect, except for stearic acid (C18:0) where PO treatment increased the fatty acid concentration by almost 3%. Palm oil supplementation decreased linoleic acid (C18:2n6c) concentration, but tended to increase the EPA (C20:3n6) in subcutaneous tissue. Similar effects were observed in fatty acids of intramuscular adipose tissue. Fatty acid concentration for treatments PO and O*E were lower in concentration of myristic acid (C14:0) and palmitic (C:16) fatty acid. Palm oil supplementation had a negative effect in stearic acid (C18:0) and arachidic acid (C20:0) and increased the fatty acid concentrations compared to treatment C and ET. Interestingly ET treatment had an increasing effect on margaric (C17:0) fatty acid concentration compared to treatment PO and O*E. Overall where oil treatment groups were of significance a reduction in fatty acid concentrations was observed in PO treatment. A decrease in fatty acid concentration was observed in PO treatment that were highly significant in linoleic acid (C18:2n6) and ?-linolenic acid (C18:3n3). If methane mitigation strategies through dietary interventions are successful in lowering the carbon footprint it can be concluded that although palm oil and/or enzyme treatment groups showed significant effects in some of the evaluated parameters, mentioned above, numerically these values were minor, and probably negligible. Although lambs in treatment groups supplemented with oil took a few days longer to reach target weight, differences between treatment groups for all other parameters, ADG, HCW, CCW, pH at 24 hours and D% (dressing percentage) were small. With no negative effects on carcass characteristics or fatty acids consumer resistance should not be at risk. / Dissertation (MSc (Agric))--University of Pretoria, 2017. / Animal and Wildlife Sciences / MSc (Agric) / Unrestricted

Globally, it is estimated that one-third of the food produced for human consumption is lost or wasted, which amounts to a concerning 1.3 billion tons per year (FAO, 2011). More concerning is the fact that much of the wastage is unnecessary because consumers often misinterpret product attributes such as date labels (i.e. sell-by; use-by and expiry-date), which they often rely on as a primary indication of product quality and/or safety. This tendency often leads to premature discarding/wastage of food products such as fresh produce. The problem is further exacerbated as current retail procedures and policies determining the date labelling on food products such as fresh produce are seldom regulated and also contribute towards food losses and wastage in the pre-and post-consumption stages. In order to reduce the current levels of food waste, it is imperative that improvements are made not only at household level, but in all stages of the supply chain, thus from farm to fork. This study first and foremost aimed to explore consumers’ current fresh produce waste practices in order to investigate date labelling as a pertinent reason for unnecessary fresh produce wastage. The study secondly aimed to explore consumers’ knowledge of fresh produce date labelling (in terms of subjective and objective knowledge dimensions), i.e. their understanding and interpretation of date labelling, not only in order to describe consumers’ current fresh produce wastage practices, but also to propose mitigating strategies. The Systems Theory was found appropriate and therefore used to guide discussions as it enabled the researcher to understand the sequence, relationship and interdependency of fundamental elements that influence fresh produce wastage. Data collection was executed in two phases. An electronic questionnaire was implemented to gather data pertaining to Phase 1. Data collection for Phase 2 relied on focus group discussions. The respondents were recruited across Gauteng using a convenience sampling technique. The overall findings regarding consumers’ food wastage revealed that fresh produce is indeed the product category wasted the most, particularly vegetables, with respondents indicating that of all fresh produce purchased per month, an estimate of 41.24% is wasted. In terms of consumers’ knowledge of date labelling, the results revealed that consumers might be somewhat overly confident (subjective knowledge). Many consumers eagerly noted that they knew enough about date labelling in order to make wise consumer decisions, but failed to present that knowledge when tested objectively. The results from the focus group discussions supported these findings and emphasised the fact that confusion in terms of Date Labelling Theory, i.e. the difference between the dimensions of date labelling (i.e. sell-by, use-by and best-before dates) is mostly the reason for misinterpretation and subsequent produce wastage. In terms of the main barriers that hinder more sustainable consumption, the results indicated that although poor planning and purchasing ranked as the most worrisome, date labelling still featured amongst the top five reasons for wastage. Possible avenues to mitigate consumers’ misinterpretation of date labelling and fresh produce wastage included: 1. Making use of an app that alerts users, 2. Removing sell by dates, and 3. Getting more support from the South African government through education and awareness campaigns. Whilst several studies have been done on household food waste practices, few have studied consumers’ subjective and objective knowledge dimensions on date labelling. To the researchers’ knowledge, this is the first paper exploring consumer date labelling knowledge and the impact it has on household fresh produce wastage practices in Gauteng. By assessing the reasons for wastage, greater insight is gained with regard to presenting possible avenues that could mitigate fresh produce wastage. / Dissertation (MConsumer Science)--University of Pretoria, 2017. / Consumer Science / MConsumer Science / Unrestricted

Functional genomic tools can be used to interrogate unique features of parasite biology that could be marked for future intervention strategies. One such unique biological feature is the atypical cell cycle of the Plasmodium falciparum parasite, with a particular interest in the key regulators that modulate the parasite’s cell cycle progression. The orderly progression of the cell cycle of the parasite allows it to undergo a vast expansion of parasite numbers during a malaria infection and cause pathologies in infected individuals. However, the precise control mechanisms and functional cascades involved in the P. falciparum parasite’s unusual cell cycle have not yet been fully elucidated. A recent study showed that gene expression profiles of the parasite switch between states of cell cycle arrest (quiescence) to cell cycle re-entry (proliferation). Global transcriptome expression data from this study was used to identify potential cell cycle regulators. The study identified a number of putative cell cycle regulators and their predicted functional interacting partners, particularly transcription factors and several members of the origin of replication complex. The study subsequently aimed to functionally validate these putative regulators in a reverse genetics approach by creating targeted disruption of the putative regulatory genes using the CRISPR-Cas9 system. Preliminary knockout studies indicated possible essential phenotypes of these putative cell cycle regulators in P. falciparum parasites. Given that cell cycle elements of the P. falciparum parasites are unique and divergent from those of the human host, the information provided in this study dissects the role of regulators in cell cycle modulation in the parasite. Not only is this important to understand parasite biology, but these cell cycle regulators are attractive potential sites for chemical interference of parasite proliferation and thereby provide as novel drug targets for antimalarial discoveries. / Dissertation (MSc)--University of Pretoria, 2017. / Biochemistry / MSc / Unrestricted

Introduction: Bone health development and maintenance is important in children to reduce the risk for osteoporosis later in life. Knowledge on the vitamin D and bone health status of preadolescent children in South Africa is limited. Vitamin D and body composition both play important roles in bone health, but the relationship between adiposity and bone mass in children has been debated. The objective of this study was firstly, to describe the bone health status, body composition and vitamin D status of preadolescent children in Pretoria, South Africa. Secondly, the study examined bone health in relation to body composition and vitamin D status. Methods: A cross-sectional study, using conveniently sampled preadolescent black children aged 5-10, was conducted. Body weight was measured with the Seca medical body composition analyser and height using the Seca 274 stadiometer. Dual x-ray absorptiometry (DXA) was used for bone health (bone mineral content (BMC), areal bone mineral density (BMD) and bone area at the total body less the head (TBLH) and lumbar spine (LS) sites) and body composition (body fat percentage, fat mass and lean mass) assessments (n = 84). Vitamin D status (25(OH)D2 and 25(OH)D3) was determined from blood spot analysis (n = 59). To compare bone health means between vitamin D status groups, children were grouped as sufficient (25(OH)D ? 30 ng/ml), insufficient (25(OH)D = 21-29 ng/ml) or deficient (25(OH)D ? 20 ng/ml) accordingly. To compare bone health means between body composition groups, children were grouped as normal (BMIfor- age Z-score ? 1) or over-nourished (BMI-for-age Z-score > 1). Simple linear regression models were used in defining the relationship between bone health parameters and body composition components. Adjustments of bone health parameters for height-for-age, gender, age and body composition components was done using multiple linear regression. Comparison between adjusted bone health parameters of normal and over-nourished were made using the student’s two sample t-test. Results: The 59 children in the vitamin D study groups had a 24% prevalence of low BMD for chronological age and 7% presented with a low BMC for chronological age. A peculiar finding was that LS-BMAD differed significantly between the vitamin D insufficient and deficient groups. There was no relationship between any bone health parameters at all sites measured and serum levels of 25(OH)D (p > 0.05). Fat mass (FM) and body fat percentage least explained the observed variation in bone health parameters, whereas lean mass (LM) was the most important body composition component in explaining the variations observed in bone health parameters. The relationship between LS bone health parameters and body composition components was weaker than the relationship between TBLH bone health parameters and body composition components. Summary and / or Conclusion: In this population, 66% of preadolescents were vitamin D insufficient or deficient, but with a healthy bone health status and 40% of the preadolescents were over-nourished with greater crude BMD than those with healthy BMI Z-scores. Vitamin D status does not appear to be associated with parameters of bone health. Lean mass was the greatest body compositional determinant for variations observed in bone health parameters. Bone health parameters of healthy and over-nourished children did not differ after adjusting for body composition. / Dissertation (MSc)--University of Pretoria, 2017. / Food Science / MSc / Unrestricted

Background: School based nutrition education programmes play a critical role in promoting positive dietary change in children. Psychosocial mediators of behaviour change such as behaviour intentions, nutrition knowledge and self-efficacy motivate children to change nutrition behaviour. Aim: To develop, implement and evaluate a school based nutrition education programme (NEP) tailored to the needs of seven to nine year olds living in resource limited settings in Pretoria, Gauteng Province, South Africa. Study design: Quasi experimental without a control group. Study setting: Two resource limited primary schools in Pretoria. Study participants: Learners, aged seven to nine years, in Grades 1-3 from the two selected schools that met the inclusion criteria. Informed consent and assent were obtained. Method: The NEP was developed based on analysis of the learners’ dietary practices data as reported by the parents and learners. These data were collected as part of the situational analysis for a larger study and was availed to the researcher on completion of the data collection. The qualitative domain was employed to determine the nutrition education (NE) needs of the learners. The study then proceeded in two phases; Phase 1, which resulted in the development of the NEP and NE materials as informed by the literature review and the outcome of the situational analysis and guided by the Social Cognitive Theory, the South African Food Based Dietary Guidelines and the six steps for designing a NEP by Contento. In Phase 2, the NEP was implemented with a conveniently selected sample of Grade 1, 2 and 3 learners from the two schools (School 1 and 2). All participants received nine nutrition lessons over six weeks. The quantitative domain was employed to evaluate the effects of the NEP on the food choice intentions of Grade 1 learners, and self-efficacy and nutrition knowledge of Grade 2 and 3 learners. Outcomes were measured at baseline, at six weeks and at 12 months respectively. A modified validated Pathways knowledge, attitudes and behaviour questionnaire was used. Paired t-test evaluated the effect of the NEP on the three outcomes and the independent samples test compared the differences between the schools and gender. The ANCOVA assessed the effect of school and gender on the measured outcomes, with the pre-assessment score as the covariate. The McNemar test was used to compare differences between related percentages. The repeated measures ANOVA was used to assess the effect of time on the measured outcomes. The statistical package SPSS version 22 was used to analyse the data and a significance level of 0.05 was employed. Ethical approval was sought from the Faculties of Education and Health Sciences of the University of Pretoria (Number: D2015/ 375A). Approval was also sought from the Gauteng Department of Basic Education (DoBE), as well as the primary schools that were involved in the study. Results: Situational analysis: The situational analysis revealed that the learners had unhealthy eating habits characterised by skipping breakfast, monotonous diets and high consumption of unhealthy energy dense foods in both the school and home environments. Some food groups such as legumes were completely missing from the learners’ diets. Evaluation of the NEP: Grade 1 (n=49) and Grade 2 and 3 learners (n=108), aged seven to nine years completed the study at six weeks and at 12 months. At post-assessment (six weeks), a significant improvement in the overall food choice intentions of Grade 1 learners was observed (M=0.41974 vs. M=0.5671; P<0.0001) (M=mean). Significant improvements were also observed in School 1 (P=0.001) and in School 2 (P=0.014) with a greater improvement in School 1. The girls in School 1 had significantly higher improvement in mean scores as compared to girls in School 2 (P=0.0001), while the boys in School 1 also had higher improvement in mean scores as compared to the boys in School 2, though not significant (P=0.275). However, at 12 months a significant decrease in the overall food choice intentions was observed from baseline to 12 months (M=0.436 vs. M=0.561 vs. M=0.446; P=0.0002) for Grade 1 learners. At six weeks, a decrease for overall self-efficacy mean scores (P=0.483) of Grade 2 and 3 learners were observed in School 1 (P=0.634) and School 2 (P=0.082), although not significant. School 1 had non significant higher mean self-efficacy scores as compared to School 2 (P=0.903). The improvement in the mean self-efficacy score was significantly higher for girls in School 1 as compared to the girls in School 2 (P=0.036). The boys in School 2 had higher non significant mean improvement of scores as compared to the boys in School 1 (P=0.351). At 12 months a significant decrease in overall self-efficacy mean scores was observed from baseline to 12 months (M=0.801 vs. M=0.791 vs. M=0.735; P=0.000) for the Grade 2 and 3 group as a whole. / Dissertation (MSc)--University of Pretoria, 2017. / Food Science / MSc / Unrestricted