PhD / Doctoral

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    Open Access
    Insect succession and changes in the soil pH and electrical conductivity associated with decomposing pig carcasses on the Table Mountain National Park of the Western Cape Province of South Africa
    (2023) Adetimehin, Adeyemi; Mole, Calvin
    The establishment of region-specific baseline data on carrion-associated entomofauna and changes in the chemistry of carrion-impacted soil is crucial in the application of forensic entomology and soil chemistry in post-mortem interval estimations. However, within the Western Cape Province of South Africa, and specifically, the Table Mountain region, no studies on carrion-associated entomofauna have been published. Also, no studies in South Africa have investigated how the changes in carrion-impacted soil chemistry can be used in post-mortem interval estimations. Therefore, to establish baseline carrion entomofauna data, this study investigated the insect assemblages associated with decomposing neonate pig carcasses, alongside the impact of carcass decomposition on soil, carcass skin, and larval mass(es) chemistry, on a monthly temporal scale across the spring, summer, autumn and winter seasons. Secondly, in line with the quest for forensic relevance as evidenced by the observations from local forensic cases within the Province, this study examined the similarity in the collected carrion entomofauna, soil, carcass skin and larval mass(es) chemistry data generated from the neonate pig studies, with those generated from singly deployed adult pig carcasses across the winter and summer seasons. Thirdly, to further establish the forensic relevance of the entomofauna data generated from experimental studies, this study examined the insect species documented in forensic entomological reports of actual forensic cases within the Western Cape Province and compared the data therein with those generated from field studies using neonate and adult pig carcasses. A total of twenty-four neonate pig carcasses (two for each monthly trial) were used to generate baseline data on carrion-associated entomofauna and changes in soil pH and electrical conductivity, carcass skin and larval mass(es) in each month across the spring, summer, autumn, and winter seasons, between August 2020 to September 2021. Similar data were collected over the winter and summer seasons respectively using two adult pig carcasses (one for each seasonal trial) between June 2022 to January 2023. The neonate pig carcasses decomposed twice as fast in the summer season when compared to the spring and autumn seasons, and four times faster than those deployed in the winter season. The adult pig carcass deployed in the summer season decomposed approximately eight times faster than that deployed in the winter season.
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    Open Access
    Is sustainable intensification possible in smallholder crop production systems in semi-arid West Africa? The case of the Red Volta and Black Volta basins in Northern Ghana
    (2023) Ansah, Prince; New, Mark; Norton, Marieke
    Food systems experts consider Sustainable Intensification (SI) a key concept to tackle the increasing global and regional food demand, particularly in semi-arid West Africa, which is prone to socioeconomic and biophysical challenges. In Ghana, crop production varies across semi-arid systems, particularly between the Red Volta and Black Volta basins. Given this context, the study assessed and compared the factors contributing to crop productivity differences between and within the RVB and the BVB and explored how these factors contribute to achieving SI goals of productivity, resilience, efficiency, and equity. This study applies an integrated SI framework and case study approach in these basins, using mixed methods: 200 household surveys, six in-depth interviews, three focus group discussions, five key informant interviews, and two workshops, with both random and purposive sampling. The results identified several important determinants of crop productivity that are relevant to SI. These included water/soil-related risks and strategies, access to agricultural resources, demographic characteristics, institutional collaboration, and household production needs. These determinants, which differ in importance within each basin, impact the achievement of SI goals. Farmers' perceptions of water/soil-related risks have a direct bearing on crop productivity across basins. Access to consistent resources was found to enhance yields, though an over-reliance on sporadic government support posed challenges especially in RVB. Demographic factors, notably age, gender, and education, emerged as significant determinants of farming practices and outcomes. Furthermore, the research emphasized the importance of robust inter-institutional collaboration in bolstering agricultural innovation and productivity. Notably, the choice of crops cultivated was influenced by a delicate balance between household consumption needs and market demands. The study underscores the need for local institutions to mitigate weak policies, limited resources, and poor knowledge transfer that could inhibit SI strategies implementation. The thesis concludes by recommending that national and local agriculture stakeholder should promote the SI concept as a guiding principle for improving existing farming systems through strengthening agriculture policies and facilitating innovations within smallholder crop production systems to enhance sustainable productivity in semi-arid Northern Ghana.
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    Open Access
    Navigating compliance challenges in African regional integration
    (2023) Nyirongo, Raisa; Kalula, E.R; Ordor Ada
    Regional integration has been pursued on the African continent for decades, with the goal of developing and uniting the continent. The determination of African leaders to implement a system of integration is evidenced by the establishment of multiple regional economic communities across the continent. One notable issue, however, is that the results attained thus far do not correspond with the efforts made. African states have seen minimal returns in comparison to the predicted benefits regional integration promised to offer. The slow progress has been attributed to, among other reasons, a lack of compliance by member states. This thesis seeks to investigate the relationship, if any, between compliance systems of RECs and the effectiveness of the community. It is recognised, on one hand, that member states have an obligation to comply with and implement community obligations. Conversely RECs have a role to play in developing systems that promote compliance within the community. The research consists of a desk review of the founding treaties of the African Union, the Sothern African Development Community, the Common Market for Eastern and Southern Africa, and the East African Community. The study analyses the systems RECs have established to promote compliance, specifically the rules systems, compliance information systems and non-compliance response systems. The research found that rules are vague and empower executive organs with great authority; RECs do not have established monitoring mechanisms, except for the AU; and there is a gap in reporting of compliance by member states. Following the analysis of compliance reporting and monitoring, the study investigates the role of community courts in enforcing community obligations. It was found that many community courts have been limited in their powers, rendering them incapacitated in enforcing community obligations. The research concludes that there is a link between compliance systems and the effectiveness of a community. To improve effectiveness, the research recommends the development of suitable compliance systems including implementing a compliance report that can be submitted by member states both regionally and at the continental level. This research contributes to the literature on regional integration, law and development in Africa. It aims to provide insight to policy makers responsible for decisions related to the design of compliance systems within regional economic communities.
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    Open Access
    Structure-activity and structure-property relationships of antimalarial pyrimido[1,2-a]benzimidazoles, imidazo[1,2-a]pyridines, and imidazo[1,2-a]pyrimidines
    (2023) Alnajjar, Radwan A Sulayman; Chibale, Kelly
    Malaria is an infectious disease that continues to cause significant morbidity and mortality in countries with poor infrastructure, with the African region being the most heavily affected. An estimated 241 million malaria cases were recorded in 2020, with 627,000 deaths. Of these, 77% occurred in children under the age of 5 years. Due to the widespread rise of parasite resistance, current treatments may no longer be effective. Furthermore, artemisinin-based combination treatments (ACTs), which are the first-line antimalarial medications currently recommended by the World Health Organization (WHO), are restricted in availability, prohibitively expensive, and have undesirable side effect profiles. Resistance to ACTs (albeit partial) has been reported in some Asian regions and in East Africa. Hence, there is an urgent need for new antimalarial agents with novel mechanisms of action and structural diversity. In 2011, pyrido[1,2-a]benzimidazoles (PBI) were reported as a promising novel antimalarial chemical series. However, one of the shortcomings of these compounds, which present a barrier to achieving optimal in vivo efficacy, is their poor aqueous solubility and suboptimal in vivo pharmacokinetics. In this study, the aim was to improve the physicochemical properties of previously identified PBI derivatives towards identifying new analogs able to address the aforementioned shortcomings. 1, 2 Three scaffolds were proposed based on their envisaged improved physicochemical properties, namely pyrimidino[1,2-a]benzimidazoles, imidazo[1,2-a]pyrimidines, and imidazo[1,2-a]pyrimidines. Compounds based on these scaffolds showed high in vitro antiplasmodium activity, with pyrimidino[1,2- a]benzimidazoles showing superior antiplasmodium activity and cytotoxicity profiles.
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    Open Access
    Economic analysis of urban water resources under drought: understanding water management and planning in South Africa
    (2023) Aina, Ifedotun; Thiam, DjibyThiam
    Water scarcity is of the utmost importance for sustaining life and human development. This growing challenge is expected to worsen because of the changing dynamics observed in many countries worldwide. The increasing demand for water, driven primarily by population growth, is one of the main factors contributing to water scarcity. As the world's population continues to grow, so does demand for water for domestic purposes. Climate change is another significant factor exacerbating water scarcity. Changing weather patterns, such as reduced rainfall and the increased frequency and severity of droughts, affect water availability, making it more challenging to meet the growing demand for water. Economic progress is also a significant factor that contributes to water scarcity. Economic development often translates to increased water usage for economic production purposes, leading to overexploitation of water resources. Consequently, many countries face water shortages, which have adverse consequences for the environment and economy. Given these changing dynamics, it is crucial to reconsider the management and allocation of water resources. Therefore, it is important to develop sustainable water management policies that balance the competing demands for water and protect the environment and economic growth. This thesis contributes to the field of water resource management by leveraging insights from economic and environmental modelling methods. This thesis presents three papers with the common goal of understanding specific themes in the water sector, namely, households' preferences for water conservation technologies, the impact of tariffs on the choice of water supply source, and policy measures to optimize water allocation decisions in large water systems. It focuses on the case of South Africa and examines the challenges of water scarcity and management, providing a comprehensive understanding of the factors driving it and possible solutions to mitigate its impacts. The focus on South Africa is important because of its economic position in sub-Saharan Africa and its complex and diverse sets of water management challenges. Moreover, similar to many arid and semi-arid regions, the country faces extreme water scarcity and a high water demand for domestic and economic purposes. Hence, this study is likely to provide insights into enhancing water management initiatives in many other water-stressed countries. The first paper on household preferences for water saving technologies contributes to the discussion on climate change adaptation strategies in urban areas. This study aimed to investigate heterogeneity among households based on their preferences for the characteristics of four different water-saving technologies. This is achieved by analyzing the attributes that would drive the installation and adoption of water-saving technologies by urban dwellers in Cape Town. Using a choice modeling framework, primary survey data were gathered from 512 urban households located in five major suburbs of the city. Four preference classes were identified to account for taste heterogeneity. The results showed that members of Classes 1 and 2 expressed a high interest in technologies that could save a significant amount of water, whereas respondents in Classes 3 and 4 preferred inexpensive conservation and behavioral habits as climate adaptation measures. These findings have significant policy implications for water-stressed and arid cities, both within and outside South Africa, as many large cities require long-term measures to alleviate the pressure on their water systems, similar to Cape Town. The second study contributes to the literature on public utility regulation. This study estimates a household water demand system and investigates the substitution threshold of piped water and self-supplied groundwater sources for the better planning of water supply systems. Using a pooled cross-sectional dataset from the South African General Household Survey (GHS), the analysis showed a high substitution threshold for piped water and self-supplied groundwater. The results also provide insights into the potential welfare impact of a stylized piped water tariff change that leads to increased piped water choices in the study area. Finally, the third study presents the development of an integrated hydroeconomic model for a large water system in which the urban and agricultural sectors are the dominant water users, and climate change presents a major environmental challenge. This study uses data from the Western Cape Water Supply System (WCWSS) and analyzes the effects of two water allocation policies: water markets and proportional sharing. The results show the enhancement of the economic benefits that can be achieved when high-value water users are prioritized. This study proposes strategies for water resource management, given the imminent impacts of climate change on water availability in the coming decades.