List of Titles

Baculovirus synergism for improved management of false codling moth Thaumatotibia leucotreta Meyr. (Lepidoptera: Tortricidae)

- Taylor, David Graham

Authors: Taylor, David Graham
Date: 2021-04
Subjects: Baculoviruses , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Biological control , Biological pest control agents , Citrus -- Diseases and pests , Codling moth , Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV)
Language: English
Type: thesis , text , Masters , MSc
Identifier: http://hdl.handle.net/10962/176942 , vital:42774
Description: Baculoviruses are an environmentally friendly and effective agent for managing lepidopteran pests. This includes the management of Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), a serious pest of citrus in Southern Africa and a major threat to the South African citrus export industry. For more than 15 years, CrleGV-SA- based biopesticides have been used as part of an integrated pest management strategy for the control of T. leucotreta in citrus orchards in South Africa, under the names Cryptogran™ and Cryptex®. While these biopesticides have been effective during this period, there are some areas in which baculovirus use could potentially be improved. Baculoviruses are notoriously slow to kill in comparison to chemical-based pesticides, and lately, pest resistance to baculoviruses has become a major concern with the development of resistance by Cydia pomonella (Linnaeus) (Lepidoptera: Tortricidae) to its granulovirus occurring in the field in Europe. The consistent use of CrleGV-SA for more than 15 years in the field has raised concern that T. leucotreta could develop resistance to this virus, and has made it necessary to alter baculovirus-based management strategies to prevent this from occurring. A second baculovirus, Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV), has recently been isolated and was shown to be effective against T. leucotreta. However, the interactions between CrleGV-SA and CrpeNPV are not yet understood and so it is important to test these interactions before both viruses are applied on the same orchards. Not only is it important to know whether these viruses could negatively impact each other, but it is also important to test whether they could interact synergistically. A synergistic interaction could not only provide a potential tool for the management of resistance, but it could also be exploited to improve baculovirus-based management of T. leucotreta. In this study, a stock of CrleGV-SA was purified by glycerol gradient centrifugation from T. leucotreta cadavers, while a stock of CrpeNPV purified from Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae) cadavers was provided by River Bioscience (Pty) Ltd. These stocks were screened for purity by a multiplex polymerase chain reaction (mPCR) protocol designed to detect CrleGV-SA and CrpeNPV. The occlusion body (OB) density was then calculated using darkfield microscopy and a counting chamber. Both stocks were shown to be pure within the limits of the mPCR protocol, and the CrleGV-SA and CrpeNPV stocks were calculated to contain 3.08 × 1011 OBs/mL and 1.92 × 1011 OBs/mL respectively The first aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the dose mortality, in terms of lethal concentration. This was calculated using 7-day surface-dose biological assays for each virus and a 1:1 mixture of OBs of the two against T. leucotreta neonates. The lethal concentrations of each treatment required to kill 50 % of larvae (LC50) and 90 % of larvae (LC90) for each treatment were then calculated and compared using a probit regression. The mixed infection performed significantly better than either virus by itself, while each virus by itself did not differ significantly from the other. The LC50 for CrleGV-SA, CrpeNPV and the mixed infection were 1.53 × 104 OBs/mL, 1.15 × 104 OBs/mL and 4.38 × 103 OBs/mL respectively. The LC90 of CrleGV-SA, CrpeNPV and the mixed infection were calculated to be 4.10 × 105 OBs/mL, 1.05 × 105 OBs/mL, and 4.09 × 104 OBs/mL respectively. The second aspect of the interaction between CrleGV-SA and CrpeNPV that was investigated was the speed of kill. A time-response biological assay protocol was created that allowed for effective observation of the larvae. This was then used to generate time-mortality data that were analysed by a logit regression function to calculate and compare the treatments at the time of 50 % larval mortality (LT50) and the time of 90 % mortality (LT90). Each virus by itself did not differ significantly from the other, while the mixed infection took significantly longer to kill 50 % and 90 % of the larvae, suggesting that there is competition for resources between viruses during the secondary, systemic phase of infection. The LT50 for CrleGV-SA, CrpeNPV and the mixed infection were 117.5 hours, 113.5 hours and 139.0 hours respectively. The LT90 for CrleGV-SA, CrpeNPV and the mixed infection were 153.2 hours, 159.3, and 193.4 hours respectively. Finally, the composition of OBs recovered from the cadavers produced by the time-response biological assays were investigated by mPCR. A method for extracting gDNA from OBs in neonate-sized T. leucotreta larvae is described. The presence of CrpeNPV along with CrleGV-SA was noted in 4 out of 9 larvae inoculated with only CrleGV-SA. The presence of CrleGV-SA as well as CrpeNPV was noted in all but one larva inoculated with only CrpeNPV, and both CrleGV-SA and CrpeNPV were noted in all but one larva inoculated with a 1:1 mixture of the two, with one larva only being positive for CrleGV-SA. This suggests either stock contamination or the presence of covert infections of CrleGV-SA and CrpeNPV in the T. leucotreta population used in this study. This is the second study to report an improved lethal concentration of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates, and the first study to report the slower speed of kill of a mixed infection of CrleGV-SA and CrpeNPV against T. leucotreta neonates. While the improved lethal concentration of the mixed infection is a promising step in the future improvement of baculovirus-based biopesticides, it is at the cost of a slower speed of kill. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
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Date Issued: 2021-04

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Biology, ecology and management of the Keurboom moth, Leto venus Cramer and the leafhopper Molopopterus sp. Jacobi in cultivated Honeybush (Cyclopia spp.)

- Mushore, Tapiwa Gift

Authors: Mushore, Tapiwa Gift
Date: 2021-04
Subjects: Legumes , Legumes -- Diseases and pests , Hepialidae , Leafhoppers , Pests -- Biological control , Entomopathogenic fungi , Leafhoppers -- Biological control , Hepialidae -- Biological control , Keurboom moth (Leto venus Cramer) , Molopopterus sp. Jacobi , Honeybush (Cyclopia spp.)
Language: English
Type: thesis , text , Masters , MSc
Identifier: http://hdl.handle.net/10962/177125 , vital:42792
Description: Honeybush, Cyclopia spp. Vent (Fabaceae), farmers have raised pest concerns following commercial cultivation. The Keurboom moth Leto venus Cramer (Lepidoptera: Hepialidae) and the leafhopper Molopopterus sp. Jacobi (Hemiptera: Cicadellidae), are two of the major pests identified in cultivated Honeybush. Laboratory and field studies were conducted to gain an understanding of the biology of these two pests to inform future pest management solutions. Additionally, entomopathogenic fungi were isolated from Honeybush farms and screened for virulence against Molopopterus sp. as a possible management strategy. This study showed that the L. venus infestation on Honeybush was a product of four fixed effects; stem diameter, species of Cyclopia, Farm location and age of the plants. Cyclopia subternata, had the highest likelihood of infestation. Increase in age of the plants resulted in an increase in the stem diameter and therefore a higher probability of infestation. Stem diameter was also shown to be a significant predictor of infestation likelihood. Infestation severity, determined by the number of larvae per plant, was shown to be influenced by three fixed effects; stem diameter, plant species and Farm location. The results also showed that L. venus prefers to initiate penetration at, or just aboveground level. Laboratory studies showed that the leafhopper Molopopterus sp. undergoes five nymphal instars with an average egg incubation time of 20 days, development time from 1st instar to adult of 26 days and average generation time of 47 days. Laboratory experiments revealed variations in host preference by the leafhopper over a period of 15 days. Cyclopia longifolia was identified to be the most preferred species for feeding compared to the two other commonly cultivated species, C. subternata and C. maculata. The results were consistent with those obtained from the field survey which showed that leafhopper density was influenced by four fixed effects; plant species, age of the plant, Farm location and harvesting practices. There were significant differences in leafhopper density in different species with C. longifolia having the highest number of leafhoppers per plant. There were differences in leafhopper density in different farms as 57% of the sampled farms had leafhopper infestations, of these farms, Lodestone and Kurland had the highest leafhopper densities. Harvested plants were shown to have significantly higher leafhopper density than non-harvested plants. Age was also shown to influence leafhopper density, which reduced with an increase in the age of the plants. A total of 20 fungal isolates were recovered from 98 soil samples of which 70% were from Honeybush fields and 30% were from surrounding refugia. Fusarium oxysporum isolates comprised 20% of the recovered isolates, with Metarhizium anisopliae isolates making up the remainder. Laboratory bioassays against adults and nymphs of the leafhopper, Molopopterus sp., showed that F. oxysporum isolates induced 10 – 45% mortality and M. anisopliae isolates induce 30 – 80% mortality. Metarhizium anisopliae isolates J S1, KF S3, KF S11, KF S13, LS1 and LS2 were the most virulent and induced over 60% mortality in both Molopopterus sp. nymphs and adults. The results of this study showed pest preference towards different Cyclopia species. As such, they should be managed differently. Furthermore, L. venus was observed to occur in low densities, hence, it cannot be considered a major pest. However, Molopopterus sp. recorded high population densities making it a major pest in Honeybush production. Positive results indicated that some of the isolated fungal isolates have potential for control, an avenue worth investigating further. , Thesis (MSc) -- Faculty of Science, Department of Zoology and Entomology, 2021
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Date Issued: 2021-04

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Constraining the role of carbonate assimilation on spinel stability in oxide ores of the Flatreef, Bushveld Complex, South Africa

- Dyan, Siyasanga

Authors: Dyan, Siyasanga
Date: 2021-04
Subjects: Oxide minerals -- South Africa -- Bushveld Complex , Transvaal Supergroup (South Africa) , Magmas -- South Africa -- Bushveld Complex , Petrogenesis -- South Africa -- Bushveld Complex , Spinel group – South Africa -- South Africa -- Bushveld Complex , Dolomite -- South Africa -- Bushveld Complex
Language: English
Type: thesis , text , Masters , MSc
Identifier: http://hdl.handle.net/10962/174578 , vital:42490
Description: The northern limb of the Bushveld Complex shows significant evidence for footwall rock- magma interaction, as a result of the emplacement of magmas onto the Transvaal Supergroup sediments. The Platreef of the northern limb is known to have involved extensive contamination of the magma. The lateral extension of the Platreef, the Flatreef, is less contaminated and comprises PGE-mineralization and thick chromitite layers. This enables successful stratigraphic correlation to the Upper Critical Zone of the eastern and western limbs of the Bushveld Complex. This study aims at addressing the influence of dolomitic floor rock contamination on the formation of spinels of the Flatreef and how they may differ to their occurrences in the Bushveld Complex elsewhere. Three main drill cores (UMT-345, UMT-335, and UMT-094) from the deep drilling program by Ivanhoe Mine, north of Turfspruit, were logged and sampled. The drill cores contained rocks contaminated by dolomite in varying degrees, depending on the proportion of carbonate xenoliths present. A total of sixty-two samples were obtained from the UG-2- equivalent chromitite seam, down into the hybrid contaminated units (Footwall Assimilation Zone; FAZ). Petrographic examination of the drill cores revealed that the feldspathic pyroxenite and chromitite layers are the most pristine lithologies in the Flatreef. The chromitite layers occur as a semi-massive to massive ores. The FAZ rocks are mainly dominated by the abundance of Al-rich Cr-spinels (Mg#30-80), clinopyroxenes with a high Ca-Tschermak component (up to 35 mol.%), olivines (Fo72-84), and plagioclase (An31-78). Geochemical characteristics of the feldspathic pyroxenite and chromitite seams include low CaO/Al2O3 and Ca/SiO2 ratios, the low abundance of REE and HFSE. In contrast, the FAZ samples display high CaO/Al2O3 and CaO/SiO2 ratios, suggesting mobilization of CaO-rich fluids derived from the associated dolomite xenoliths. Observations from lithostratigraphic element profiles indicate spikes in CaO within FAZ units relative to the feldspathic pyroxene, indicating a secondary source of CaO linked to proximity to carbonate xenoliths intersected in the core. The assimilation-fractional crystallization model performed with the Upper Critical Zone parental melt and dolomite produced assemblages dominated by spinel, olivine, clinopyroxene, and plagioclase, relating to those of the most contaminated rocks of footwall assimilation zones. The model also showed that large quantities of CO2 were produced during assimilation. High amounts of CO2-fluids mobilized in the melt would have interacted with the melt and increased the overall oxidation conditions. Oxygen fugacity (ƒO2) values were constrained from the spinels in the FAZ and chromites in chromitite seams. Spinels within the most contaminated rocks of the FAZ recorded relatively high ƒO2 values ranging between NNO-0.2 and NNO+1.8 (relative to the Nickel-Nickel-Oxide buffer. High ƒO2 values in spinels from the FAZ suggest that the melt interacted with greater amounts of oxidative CO2-fluids during decarbonation reactions. Such high redox conditions could have triggered the saturation and crystallization of spinels. Comparison of mineral compositions and ƒO2 of UG-2 chromites from the Flatreef with UG-2 from the eastern limb, western limb, chromitites from the Platreef and Uitkomst Complex reveal that Flatreef chromites are of most similar to those of the Platreef Uitkosmt Complex. The northern limb and Uitkomst Complex chromites have high ƒO2 values (NNO+0.3 to NNO+1.2), indicating their apparent link to the Malmani dolomite. Interaction of magma with the Malmani dolomite would have produced high quantities of CO2, triggering an increase in oxidizing conditions. Such an effect is most prominent in the Flatreef chromitites that are in contact with the FAZ. The chromites are characterised by high ƒO2 (NNO+1.2) and distinct compositions (low Cr2O3, high Fe3+/Fetotal, and TiO2). Thus, it is proposed that carbonate assimilation in the Flatreef triggered the precipitation of these distinctive chromites proximal to FAZ, due to liberation of substantial amounts of CO2-rich fluids with a highly oxidative capacity. Carbonate assimilation in layered intrusions can be used as a monitor potential precipitation of chromites. , Thesis (MSc)--Rhodes University, Faculty of Science, Department of Geology, 2021
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Date Issued: 2021-04

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Creating shared value through innovating business models: a case study of the Mapela Water Project

- Moyo, Bonnie

Authors: Moyo, Bonnie
Date: 2021-04
Subjects: Business planning -- South Africa , Strategic planning -- South Africa , Sustainable development -- South Africa , Social responsibility of business -- South Africa , Mineral industries -- South Africa , Mapela Water Project , Hourglass Model
Language: English
Type: thesis , text , Masters , MBA
Identifier: http://hdl.handle.net/10962/177135 , vital:42793
Description: Shared value creation is a contemporary concept that aims to address the strained relationship between business and society through business models that expand the competitive advantage of business while addressing societal challenges in the business environment. Being a novel concept, studies on how value is created and shared are limited, especially where the unit of analysis is a specific project. This paper investigates how value is created and shared among stakeholders using a water project case study reported as a shared value initiative. The investigation is considered under the Hourglass Model (Ludeke-Freund, Massa, Bocken, Brent and Musango, 2016) as a guiding framework. This sustainable business model is suggested as a business model that creates shared value. The study uses a qualitative research approach to investigate the inputs into the Hourglass Model (Ludeke-Freund et al., 2016) in the form of capitals, briefly considers the business models of specific stakeholders and then analyses the value created, missed and destroyed for each stakeholder through their value creation mechanisms. In the findings, six different capitals are identified from the participating stakeholders, and the value created, destroyed, and missed is discussed in the context of shared value principles. The findings show that capitals are used as inputs into the Hourglass Model and are consumed, created, and regenerated. There is also the realisation from the findings that different stakeholders required different and varying amounts of the six capitals identified. The interconnectedness of the capitals is shown in the study, and the findings show that the context of the environment within which a project operates contributes to the creation of shared value. As with the six capitals, the findings show that multiple stakeholders create shared value confirming stakeholder theory's guiding principles regarding stakeholder salience, which are relevant for creating shared value. Some stakeholders are identified as being more important to creating shared value in the project than others. Trade-offs are then required for value creation from a finite pool of capitals and stakeholders to consider the capitals and stakeholders' long and short-term impacts. Identifying stakeholders and the capitals allowed the researcher to consider the value created, destroyed and missed in the project. This assessment of shared value generated forms part of the findings on business models' outcomes for shared value, summarised for the project. Based on these areas where the outcomes are missing or destroying value, recommendations are made to address these opportunities, and an area of further research is identified. Drawing on these outcomes, developing clusters as per the value creation avenues of shared value would be the most appropriate avenue for this project. The study adds to the shared value body of knowledge by operationalising the Hourglass Model (Ludeke-Freund et al., 2016) and illustrating how the Model can be used to consider shared value creation. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2021
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Date Issued: 2021-04

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Customer perceptions on Customer Relationship Management (CRM) and its possible influence on Revenue Management (RM) at a selected water board in South Africa

- Manyonganise, Joshua Anesu

Authors: Manyonganise, Joshua Anesu
Date: 2021-04
Subjects: Customer relations -- Management , Revenue management -- South Africa -- Eastern Cape , Municipal government -- South Africa -- Eastern Cape , Municipal services -- South Africa -- Eastern Cape , Water-supply -- South Africa -- Eastern Cape , Amatola Water (Utility) , South Africa. National Water Act, 1998
Language: English
Type: thesis , text , Masters , MCom
Identifier: http://hdl.handle.net/10962/177214 , vital:42800
Description: The primary activity of water boards is to provide water services (bulk portable, and bulk wastewater) to other water services institutions within its respective service areas. They may perform other activities under conditions set out in the Water Services Act of 1997. Water boards’ revenues come from the municipalities they deliver services to. Not all municipalities have been paying for the services delivered to them, which led to the aim of this study being to gauge the perceptions of Water Board X and Water Board X’s customers of selected Customer Relationship Management (CRM) factors (service quality, customer involvement, customer value, information technology, and management commitment) that may possibly influence Revenue Management (RM). This could possibly assist Water Board X in the future to improve its revenue and debt collection. This thesis employed an interpretivist qualitative research methodology to explore its research aims and objectives. Open-ended semi-structured interviews were conducted with thirteen participants from Water Board X and four municipalities which Water Board X provides services. The data collected from the interviews were analysed manually through thematic analysis. The outcome of the interviews noted that an organisation that delivered high levels of service quality to its customers, could possibly improve its RM as the customers are of the opinion that their needs and requirements have been met and would be willing to pay for the services rendered. It was furthermore found that an organisation that involves its customers could possibly improve its RM as the organisation constantly communicates with its customers during, for example, the different stages of a project to ensure that the organisation does not deliver a project that does not meet the customers’ requirements at the end of the project life cycle. In addition the use of information technology played a pivotal in an organisation as the use of information technology assisted to develop effective methods in customer relationship management such as, data management, improving communication within the organisation, and with the customers, and the decision making. Furthermore, this study suggested the importance for an organisation to add value to the services that they deliver and for an organisation’s management to be committed to ensure that their customers’ expectations and requirements are met. The findings of the study suggest that CRM factors (service quality, customer involvement, customer value, information technology, and management commitment) could influence RM, and it is suggested that Water Board X adopts CRM strategies accordingly to improve its RM. Some of these strategies include adopting a coherent and sustainable revenue strategy through the use of appropriate tariff structures that are simple, equitable, affordable, financially sustainable, and transparent for all; showing commitment by prioritising water loss management and by properly auditing water supplies and water treatment revenue while increasing efficiency in supply and revenue recovery as this allowed Water Board X to better serve its customers, improve its financial standing, and allocate funding for water infrastructure upgrades and to adopt technologies that are on the market as these technologies can detect leakages, manage payments, control water flow and transmit data. , Thesis (MCom) -- Faculty of Commerce, Department of Management, 2021
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Date Issued: 2021-04

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Does the Transkei population of Haliotis Midae at the eastern edge of its distributional range have a higher thermal tolerance than those in more temperate waters?

- Mathebula, Surprise

Authors: Mathebula, Surprise
Date: 2021-04
Subjects: Haliotis midae -- South Africa -- Indian Coast , Abalones -- South Africa -- Indian Coast , Haliotis midae -- Effect of temperature on -- South Africa -- Indian Coast , Haliotis midae -- Physiology -- South Africa -- Indian Coast , Haliotis midae -- Adaptation -- South Africa -- Indian Coast , Haliotis midae -- Growth -- South Africa -- Indian Coast
Language: English
Type: thesis , text , Masters , MSc
Identifier: http://hdl.handle.net/10962/177360 , vital:42814
Description: The South African perlemoen abalone (Haliotis midae) may be vulnerable to rising temperatures on the East coast of South Africa due to climate change. H. midae is South Africa’s most valuable aquaculture species, and it is thus important to understand its physiological ability to adapt to the expected changes and to identify possible management measures to mitigate the impacts of rising temperatures. This project aimed to understand thermal tolerance and growth rates of offspring from two H. midae populations originating from the warm-temperate Central region (Port Elizabeth) and warmer Eastern edge of the species’ distribution in the Transkei region. To determine the effects of temperature on the physiological performance of the two abalone populations, growth rates, oxygen consumption rates and critical thermal maxima (CTM) were compared. A laboratory growth trial was conducted at three controlled temperatures, visibly, the ‘optimal’ temperature for H. midae growth (18 - 20℃), ‘pejus’ (stressful) temperature (21 - 22℃) and ‘critical’ temperature (23 - 24℃). Oxygen consumption rates were recorded at optimum (20℃), pejus (22℃) and critical (24℃) temperature using a respirometer. In addition, a farm growth trial with simultaneously spawned cohorts of abalone from the two populations was conducted at ambient temperature (19.5 and 20.0℃). The laboratory growth trial revealed no significant differences in growth rate between the two populations at the three temperature treatments (ANOVA, P > 0.05; df = 2). However, mortalities were high and growth rates low, indicating that the rearing conditions were sub-optimal, possibly masking genetic differences. No significant differences were observed in oxygen consumption rates (ANOVA, P = 0.18; df = 2), and CTM (t-Test, P = 0.31; df = 3) between the two populations. The CTM for both populations was between 29 - 30℃. The farm trial yielded no significant differences in growth rate during the Nursery phase (t-Test, P = 0.25; df = 2), however significant differences in growth rate were observed during the grow out phase with the Central region abalone offspring growing faster than the Eastern edge population (t-Test, P = 0.04; df = 4) indicating the possibility of a genetic difference between the two populations. Further experiments will be required to determine whether the differences observed in the growth trial were genetically or environmentally induced. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2021
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Date Issued: 2021-04

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Economic impact of climate change on maize production in the Free State Province, South Africa

- Johnson, Richard Cowper

Authors: Johnson, Richard Cowper
Date: 2021-04
Subjects: Corn -- Climatic factors -- South Africa -- Free State , Climatic changes -- Economic aspects -- South Africa -- Free State , Climate change mitigation -- South Africa -- Free State , Agriculture -- Economic aspects -- South Africa -- Free State
Language: English
Type: text , Thesis , Masters , MCom
Identifier: http://hdl.handle.net/10962/174365 , vital:42471
Description: Higher concentrations of CO2 in the atmosphere is a major influence on climate change globally. Climate change is caused by greenhouse gases trapping too much heat from the sun in the atmosphere and thus, altering the climate through a rise in global surface temperatures and changing precipitation patterns. CO2 is the most prominent greenhouse gas found in the atmosphere and it is reported that by the turn of the century the CO2 concentration levels will have doubled if the current rate of emissions continues. However, the increase in atmospheric levels of the gas has been found to increase the capacity of maize plants and their water use efficiency to achieve higher yields through CO2 fertilisation. Simulation experiments conducted by the Rhodes University Botany Department found that the effect of elevated levels of CO2 of double the current concentration offsets the negative effects of drought on maize. A case study was conducted on commercial maize farmers in two regions of the Free State province in South Africa to estimate the economic impact of climate change on maize production. Although production is increasing in the province, adaptation to the changing climate is key to the sustainability of production. There is a trade-off between the negative effects of higher CO2 levels changing the climate and the positive effect of CO2 fertilisation. As predicted, the economic impact of climate change is the disruption of farming practices and the increase in costs of production as a result of adapting to climate change. Using a gross margin analysis, the study found that the larger maize farmers who benefit from economies of scale are able to adapt and grow their production whilst the smaller farmers are being pushed out of the market.
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Date Issued: 2021-04

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Exploring how Grade 9 Physical Science teachers mediate learning of the topic of chemical changes

- Likando, Orrice Munukayumbwa

Authors: Likando, Orrice Munukayumbwa
Date: 2021-04
Subjects: Science -- Study and teaching (Secondary) -- Namibia , Chemistry -- Study and teaching (Secondary) -- Namibia , Culturally relevant pedagogy , Pedagogical content knowledge , Prior learning -- Namibia
Language: English
Type: thesis , text , Masters , MEd
Identifier: http://hdl.handle.net/10962/177918 , vital:42890
Description: The examiners’ reports for 2013-2018 indicated that learners consistently perform poorly in questions based on chemical changes. My assumption is that the reason why learners are challenged with understanding the topic of chemical changes could be due to the way this topic is taught. It is against this background that this study explored how grade 9 Physical Science teachers mediated learning of the topic of chemical changes. The study is underpinned by an interpretive paradigm. Within the interpretive paradigm, a qualitative case study research design was employed. It was conducted at two different schools in the Otjozondjupa region with two Physical Science teachers. Data were collected using semi-structured interviews, lesson observations, stimulated recall interviews, and teachers’ reflections. The study is informed by Vygotsky’s socio-cultural theory together with Shulman’s pedagogical content knowledge as the theoretical frameworks. A thematic approach to data analysis was adopted. That is, qualitative data were analysed inductively to come up with sub-themes to form themes. Moreover, validation and trustworthiness were completed through data triangulation, member checking, and watching videotaped lessons with the participants. The findings of this study revealed that the topic of chemical changes has many examples which can be used during mediation. Teachers seemed to be aware of integrating learners’ experiences into their lessons. Furthermore, they were aware that they should improvise resources during mediation of learning. In contrast, during lesson observations, the findings revealed an imbalance between this awareness and the actual knowledge of using easily accessible materials, and the elicitation and integration of prior knowledge throughout the science lessons. Moreover, hands-on practical activities were lacking in the mediation process and instead, traditional methods of teaching tended to dominate. Nonetheless, teachers’ reflections influenced them to analyse and strengthen their lessons. Thus, the study recommends that there is a need for teachers to have mentorships and platforms which can expose them to the knowledge of different types of easily accessible materials. This might strengthen their PCK. Teachers are also encouraged to do some reflections after very lesson as these have a potential to influence their pedagogical practices. , Thesis (MEd) -- Faculty of Education, Education, 2021
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Date Issued: 2021-04

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Exploring the influences of an intersemiotic complementarity teaching approach on Grade 9 Namibian learners’ sense-making of chemical bonding

- Aikanga, Frans Paulus Shintaleleni

Authors: Aikanga, Frans Paulus Shintaleleni
Date: 2021-04
Subjects: Physical sciences -- Study and teaching (Secondary) -- Namibia , Chemical bonds , Semiotics , Cognition in children , Communication in education , Language and education -- Namibia , Visual learning , Verbal learning
Language: English
Type: thesis , text , Masters , MEd
Identifier: http://hdl.handle.net/10962/178281 , vital:42927
Description: Anecdotal evidence from my 10 years’ experience teaching Grade 9 Physical Science in Namibian schools revealed learners’ difficulty with making sense of chemical bonding. The Junior Secondary examiners’ reports in recent consecutive years (2014, 2015, 2016 & 2017) also revealed this challenge among Grade 10 learners (Namibia. Ministry of Education, Arts and Culture [MoEAC], 2017). The language of learning and teaching (LoLT) for most school subjects (including Physical Science) in Namibia is English, which is taken as a second language by most learners (Kisting, 2011). The results of the English Language Proficiency test written by all principals and teachers in Namibia show that most are not proficient in this language (Kisting, 2011). This has raised concern as to how teaching of content subjects may be undertaken effectively with English as the LoLT. In Namibia, chemical bonding is part of the chemistry section of Physical Science, taught as a sub-topic under the Matter section, where the nature, characteristics, and behaviour of three states of matter are explained. The difficulty students have with chemical bonding is identified as being due to complex chemical concepts (Chittleborough & Mamiala, 2006), and the specialised language of the topic these concepts involve (Gilbert & Treagust, 2009). Additionally, this difficulty may be ascribed to lack of suitable pedagogic approaches, which is linked to science teachers not being fluent in the LoLT. Despite this link, Johnstone (1982) posits that addressing the challenge of teaching and learning chemical knowledge requires teachers’ understanding of three levels of representation: macroscopic, sub-microscopic, and symbolic. Addressing this challenge may be accomplished by using multimodality in teaching, which is achievable via intersemiosis of different semiotic modes, drawing from Systemic Functional Linguistics. This is due to non-linguistic modes also having the potential to make meaning as language does, and the fact that language alone cannot fully enable effective meaning-making in discourses that are inherently multimodal, such as science. Some studies have suggested that the intersemiosis of visual and verbal semiotic modes has the potential to enable more meaning-making of scientific discourse than either of these two alone. The study reported on in this thesis has built on such previous studies in order to explore the influences of a visual-verbal intersemiotic complementarity teaching approach on Grade 9 Namibian learners’ sense-making of chemical bonding. No studies from Namibia exploring these influences on Grade 9 learners could be found. This revealed the knowledge gap that this study aimed to contribute to filling. I accomplished this goal by embarking on a two-cycle action research study. The first cycle followed a traditional teaching approach and assessment, whereas the second cycle, the intervention, included a visual-verbal intersemiotic complementarity teaching approach and assessment. I achieved visual-verbal intersemiotic complementarity teaching and assessment by coordinating spoken and written language with visuals in the form of diagrams and physical models. The critical paradigm was adopted to explore the influences of this pedagogic approach, with the underlying aim of exploring the intervention approach for bringing about a change in learners’ sense-making of chemical bonding, compared to traditional approaches that do not consider intersemiosis. This study is informed by Vygotsky’s (1978) social constructivism to account for learning as a product of social construction, and Halliday’s (1978) Systemic Functional Linguistics to account for the role played by semiotic modes in making meanings. This study involved collecting qualitative data that were accessed via document analysis, structured lesson observation, the teacher’s and learners’ reflective journals, and the pre- and post-test. Collecting these data was facilitated by a critical friend. The results reveal a positive influence of the visual-verbal intersemiotic complementarity teaching approach on Grade 9 Namibian learners’ sense-making of chemical bonding. This influence was realised in the noticeable shift from the learners’ discourse (use of talk and visuals) being perceptual (which is less scientific) to being idea-based (which is more scientific). Learners were also found to be self-motivated and keen to learn complex chemical bonding concepts after the intervention – another sign of their making sense of the topic. The implications of this study include that visual-verbal intersemiotic complementarity should be considered a pedagogic approach to chemical bonding by curriculum developers and reviewers, teacher training institutions, and science textbook authors. , Thesis (MEd) -- Faculty of Education, Education, 2021
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Date Issued: 2021-04

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Framing realities : a critical analysis of perspectival distortion in the film Alice by Czech Surrealist Jan Švankmajer

- Soutter, Simone

Authors: Soutter, Simone
Date: 2021-04
Subjects: Švankmajer, Jan, 1934- -- Criticism and interpretation , Depression, Mental -- Exhibitions , Perception , Frames (Sociology) , Surrealism -- Influence , Cubism -- Influence , Surrealism in motion pictures , Depression, Mental in art
Language: English
Type: thesis , text , Masters , MFA
Identifier: http://hdl.handle.net/10962/178365 , vital:42933
Description: My MFA exhibition Through the looking glass; altered states of perception, explores my experience of mental distress: Major Depressive Disorder (MDD), through the medium of painting and multimedia collage. Situated in the Main Fine Art building on Rhodes University campus, this practical submission takes the form of a collection of oil paintings accompanied by an immersive wall of collaged experimentations, depicting the perspectival shifts I have experienced in coping with mental distress. The paintings explore concepts of framing and perspective, both literally and metaphorically in unpacking how our perceptions are manipulated by the way in which situations and concepts are framed. I use strategies and techniques drawn from the Surrealist and Cubist movements in order to depict my distorted experience of time and space, but also to tap into my own unconscious. In this mini-thesis: Framing realities; A critical analysis of perspectival distortion in the film Alice by Czech Surrealist Jan Švankmajer, I explore the strategies and concepts developed during the Surrealist and Cubist movements in relation to strategies used by Švankmajer in his disturbing interpretation of Alice’s Adventures into Wonderland. Here, he visually explores the psyche of an imaginative child. His unique interpretation is expressed through the combination of live-action film and stop-motion animation. I position my work in relation to themes proposed by Maurice Merleau-Ponty, Ernst Jentch, Sigmund Freud and Julia Kristeva. In the first Chapter: Framing and Perspectival shifts, I unpack framing and perspectival shifts exhibited in the Cubist (a physical shift), Dadaist (a social shift), and Surrealist (an unconscious shift) movements. In Chapter Two: A critical analysis of Alice by Jan Švankmajer, I engage in an analysis of themes (examined in the above art movements) relative to the film Alice. These are found objects and assemblages, ambiguity, distortion of scale, the Unconscious, the uncanny and multi-sensory modalities. Chapter Three: Through the Looking Glass; Altered states of perception, I discuss how the themes discussed in Chapter Two apply to my own body of work and how these themes are addressed with regards to my lived experience of mental disorder and distress. , Thesis (MFA) -- Faculty of Humanities, Fine Arts, 2021
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Date Issued: 2021-04

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Hierdie keer gaan nie maklik wees nie

- Visser, Deon Claudius

Authors: Visser, Deon Claudius
Date: 2021-04
Subjects: Creative writing (Higher education) -- South Africa , Diaries -- Authorship , Short stories, Afrikaans -- 21st century , Afrikaans fiction -- 21st century , Afrikaans fiction -- History and criticism
Language: Afrikaans
Type: thesis , text , Masters , MA
Identifier: http://hdl.handle.net/10962/178317 , vital:42929
Description: My tesis bestaan uit twee versamelings van prosa wat verwant en in noue verband met mekaar tree. Die prosa is fragmentaries en kort maar verbind met ‟n oorkoepelende storie wat in beide Afrikaans en Engels voorgelê word. Die Afrikaanse deel van my tesis ondersoek die verlede, en die Engels die toekoms. My algemene bron van inspirasie vir die struktuur en voorlegging van die tesis word verkry vanaf die klassieke raamverteller konvensie soos gebruik in One Thousand and One Nights, hierdie konvensie maak gebruik van raamfragmente wat binne ‟n groter geheel gevind kan word. Dit is juis hierdie komplekse struktuur wat dit moontlik maak om tyd, hede en verlede asook die toekoms, te kan ondersoek en uit te beeld. Verder maak dit dit ook moontlik om gekoppelde herinneringe, gedagteneigings, en fantasieverhale te kan gebruik as die dryfkrag van die oorkoepelende storie. Met betrekking tot kontemporêre fiksie vind ek die meeste aanklank en invloed by Sandra Cisneros se boek House on Mango Street. Ek het by hierdie verhaal geleer hoe om vignette en kortverhale onafhanklik maar met ‟n motief-verbinding aan mekaar te koppel. Tematies gesproke handel my tesis oor herinneringe, nostalgie, familieverhoudings, die dood asook afsluiting en aanbeweging. In terme van hierdie temas vind ek dat Nathan Trantraal se Chokers en Survivors, en Noudat Slapende Honde deur Ronelda S. Kamfer my die meeste insae gee oor die verhouding tussen Afrikaans en Engels in die literatuur. Verder is Loftus Marais se taalgebruik en die vermenging van taal in Staan in die Algemeen Nader aan Vensters ook insiggewend. , Thesis (MA) -- Faculty of Humanities, School of Languages and Literatures, 2021
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Date Issued: 2021-04

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How selected Grade 7 participants develop conceptual understanding in solving algebraic problems as a result of participating in a screencast intervention

- Wienekus, George Renier

Authors: Wienekus, George Renier
Date: 2021-04
Subjects: Algebra -- Study and teaching -- South Africa , Mathematics -- Study and teaching (Elementary) -- South Africa , Problem solving in children , Algebra -- Ability testing , Algebra -- Computer-assisted instruction
Language: English
Type: thesis , text , Masters , MEd
Identifier: http://hdl.handle.net/10962/176833 , vital:42763
Description: This research project is an interventionist case study, oriented in the interpretive paradigm, which aims to investigate how selected Grade 7 participants develop conceptual understanding in solving algebraic problems as a result of participating in screencast interventions. The aim of my screencast intervention programme, which lies at the heart of this study, is to develop practices, inter alia, of how such devices and software may be “used to develop conceptual rather than procedural or decorative knowledge” (Larkin & Calder, 2015:1) in solving linear equations. The planned intervention was delivered in the form of a series of screencasts: these take the form of audio-video lessons with an emphasis on the visual impact, and were recorded using an application called Explain Everything. The screencast interventions were delivered via Google Classroom and included animations supported by such conceptual explanations of early algebra as are relevant to Grade 7 students, and in line with the South African Curriculum and Assessment Policy Statements - Department of Education, 2011. The fundamental components of an early algebraic equation that would be relevant to a Grade 7 student were considered and used to develop an analytic framework. This was based on a taxonomy designed according to four identified “clusters” in order to analyse the workings of the purposefully selected Grade 7 participants who were video recorded and questioned in a talk-aloud interview while they completed a post-intervention pencil-and-paper test. What emerges from this research project is that there is a significant need for specific and concentrated technology-based techniques, such as the interventions undertaken here, and that exploration and development in the field could benefit the delivery of a pedagogy for algebra. The pedagogical methods implemented and studied in the form of screencasts proved to be successful and were well received by the learners particularly in relation to the conceptualisation of “symbol sense” and transformation in early algebra. The structure and design of the screencast interventions were important in supporting the acquisition of these concepts and were demonstrated to be worthwhile tools for an epistemological application in a classroom or teaching context. , Thesis (MEd) -- Rhodes University, Faculty of Education, Education, 2021
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Date Issued: 2021-04

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Impact of sovereign credit ratings on emerging bond and stock market returns

- Mkhonto, Zoyisile

Authors: Mkhonto, Zoyisile
Date: 2021-04
Subjects: Rating agencies (Finance) , Credit ratings , Bond market
Language: English
Type: thesis , text , Masters , MCom
Identifier: http://hdl.handle.net/10962/177170 , vital:42796
Description: The primary role of credit rating agencies is to reduce asymmetric information between the parties in a lending relationship. The three major rating agencies have received extensive criticism over the years. These rating agencies have been accused of providing inaccurate ratings which ultimately led to various financial calamities. Late rating action has also been blamed for exacerbating financial and economic cycles. Moreover, there is an argument that emerging markets are unfairly rated in comparison to developed economies. Hence, the reliability and informational value of the assessments provided by credit rating agencies is met with scepticism. Despite these criticisms, rating agencies are characterised as gatekeepers to capital and credit ratings remain essential financial market indicators. Albeit, the literature regarding the impact of sovereign credit ratings on bond and stock markets is inconclusive. This study aims to add to the body of literature and provide insights into the informational value of sovereign credit ratings in emerging markets. More specifically to estimate the relationship between various sovereign credit rating announcements, and bond and stock market returns. Also, to examine whether sovereign credit ratings have a differential impact between bond and stock markets. As well as address the question does it matter who provides the rating? Using an event study, abnormal returns surrounding rating announcements from 2009 to 2019 for 24 emerging markets were analyzed. Firstly, this study concluded that sovereign credit ratings are informative. Secondly, the degree of informativeness differs between the bond and stock markets. Thirdly, an asymmetrical impact was observed between the types of rating announcements. Lastly, that it does matter which rating agency provides the rating because each agency has a unique reputation. The findings of this research have implications on how investors and portfolio managers decide on asset allocation. Furthermore, policymakers may find our investment grade analysis of value when evaluating regulatory reform. It’s recommended that future research refines the event methodology and examines country specific characteristics within each of the emerging markets. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2021
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Date Issued: 2021-04

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