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The spatial extent, practices, and impacts of illegal solid waste dumping across an income gradient in Makhanda and Knysna, South Africa
Get PDFThe disposal of household solid waste (HSW) through illegal dumping has become a widespread issue globally, especially in developing countries. The problem has been exacerbated by several factors such as rapid population growth, urbanization, poor infrastructure, poor enforcement of bylaws, mismanagement, poor municipal service delivery, and lack of funding, resulting in most urban residents resorting to illegal solid waste dumping (ISWD). Illegal solid waste dumping by urban residents in most developing countries is becoming a standard occurrence particularly along roadsides, vacant plots, riverbanks, forests edges, and in commonages near and within human settlements. In most South African towns and cities, the practice of ISWD is an immense social, economic, and environmental problem. The practice has led to nationwide environmental pollution and has posed significant socio-economic and health risks to urban residents particularly the urban poor, who reside in areas where ISWD is more pronounced. Studies on ISWD in South Africa are mostly within metropolitans and cities neglecting medium-sized towns like Makhanda and Knysna where such information is needed to improve municipal household solid waste (HSW) management plans and policies. Using street surveys, illegal dumpsite mapping, waste categorization templates, and household survey interviews the study examined the spatial extent, composition, dumpsite sizes, as well as residents’ practices and perceived causes and impacts of ISWD across different income groups in two medium-sized towns of Makhanda and Knysna, South Africa. The results showed that more dumpsites were enumerated in Makhanda (155) than in Knysna (60), however, the occurrence, size and prevalence of illegal dumpsites were unevenly distributed, with most dumpsites being in low-income compared to high-income neighbourhoods. In both towns, most of the dumpsites were within open access areas such as roadsides, vacant plots, and commonages. The composition of waste within dumpsites consisted mostly of household waste (Makhanda = 42% and Knysna = 49%), garden waste (Makhanda = 37% and Knysna = 30%), and construction waste (Makhanda = 21% and Knysna = 21%). More residents in low-income than in high-income neighbourhoods reported dumping, attributing it primarily to poor municipal services (Makhanda= 59% and Knysna= 54%). Within both towns, environmental impacts of ISWD were experienced by residents from both income groups, with over 50% of the respondents citing visual pollution as the most serious impact. The health impacts of ISWD were exclusively reported by low-income residents with over 30% reporting TB and Rashes as the key health impacts. Overall, the research concluded that ISWD distribution, prevalence, dumpsite sizes and impacts were unevenly distributed across low-income and high-income neighbourhoods with the former disproportionately facing v an overall higher occurrence of illegal dumpsites and subsequent health risks. The occurrence of more dumpsites in low-income areas seem to suggest that factors like socio-economic inequalities, historical legacies, lack of education and awareness, and poor municipal services in these areas are at play and need to be addressed to mitigate ISWD. To tackle the problem of ISWD a collaborative approach is recommended, one that incorporates stakeholders, households and municipal efforts and improvements. Such solutions could include improved municipal funding to develop an efficient service delivery system, solid waste awareness campaigns in communities, and provisioning of bins along open access areas.Thesis (MSc) -- Faculty of Science, Environmental Science, 202
Cocrystals, salts and eutectics of anti-tuberculosis medicines
No full textTuberculosis remains as a prominent cause of death worldwide. This infectious disease is treated with first and second line drugs. However, challenges of multi drug resistant tuberculosis and adverse side effects such as depletion of essential B group vitamins in the body by first line drugs, as well as poor physicochemical properties of second line drugs persist. Cocrystallisation of anti-tubercular drugs with various coformers has therefore been used as an alternative method to improve the physicochemical properties of active pharmaceutical ingredients (API) while maintaining their efficacy. The main objective of this study was to carry out cocrystal screening of anti-tubercular API and vitamin B coformers to make drug-drug or drug-vitamin multicomponent complexes. Preparation of the multicomponent complexes was carried out by mechanochemical grinding (neat grinding (NG), liquid assisted grinding (LAG) and slow evaporation. All complexes were characterised using Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and crystal structures were elucidated using single-crystal X-ray diffraction (SCXRD). The cocrystal screening resulted in the formation of various solid forms, which included cocrystals, salts and eutectic products. Two cocrystals of 4-aminosalicylic acid (PAS) were isolated and characterised. The cocrystal of PAS with isoniazid (INH) demonstrated similar characteristics for both the bulk crystalline material and milled materials. The cocrystal of PAS and pyrazinamide (PYR) prepared using mechanochemical synthesis was met with challenges, while difficulties were also encountered in obtaining suitable crystals for SCXRD analysis. The ground and recrystallised samples of the PAS and pyrazinecarboxylic acid (PCBA) showed distinct differences in their thermal behaviour, with SCXRD revealing the decomposition product phenolammonium-pyrazinecarboxylate salt ‘sans’ the CO2 moiety. Salt formation involving pyridoxine (PN) yielded a salt hydrate with PAS (PN-PAS) and an anhydrous salt with PCBA (PN-PCBA). Both salts exhibited very complex packing arrangements with equally complex thermal behaviour depending on the solvent used during preparation, and the method of preparation. Three eutectic systems involving INH with PYR, PN and pyridoxine hydrochloride (PNꞏHCl) were identified, and their phase diagrams were constructed from DSC data. The eutectic compositions obtained were 1:1 for INH:PYR, 1:1 for INH:PN and 6:4 for INH:PNꞏHCl. Finally, a total of eight multicomponent complexes were prepared using selected API and vitamin B6 components. The results presented here provide motivation for further investigation and evaluation of the pharmacochemical properties of these API.Thesis (MSc) -- Faculty of Science, Chemistry, 202
A review of African praying mantises (Dictyoptera: Mantodea) incorporating molecular and morphological data
Get PDFPraying mantises (Dictyoptera: Mantodea) are an iconic group of predatory insects, comprising around 2500 species globally, that occur in all zoogeographic regions except the poles. Their presence in the social psyche of many cultures has existed for millennia, but until the past decade, Mantodea has received little attention from the scientific community as the constituent species are of little economic or medical importance. Africa is rich in praying mantis diversity, accounting for approximately 45% of all described species, yet it remains largely under-sampled compared to the New World and Asian regions. Recent exploration of Gabon and Central African Republic have proved fruitful, with new species descriptions being major highlights. A recent re-cataloguing of southern African praying mantises has proved useful as specimen identifications were checked, new distributions were recorded, and most importantly, it was revealed that museum collections have significantly more diversity than previously recorded. A meta-analysis of African praying mantises was conducted; we present a species checklist to the countries of Africa, including Madagascar and surrounding islands. Currently, 17 families, 182 genera, and 1104 species occur in Africa.Historically, the classification of praying mantises was based solely on morphological features, and the novelty of the field at the time made it unclear which characteristics were of taxonomic importance. The onset of molecular systematics brought attention to incongruences between morphological and molecular phylogenies, believed to be attributed to convergent evolution masking the underlying evolutionary processes that occurred. Significant progress has been made in the past two decades regarding Mantodean classification and most described genera have their phylogenetic position. With the addition of more African taxa, we present mantodean phylogenies for molecular and morphological data. Molecular phylogenies were estimated through Bayesian Inference and Maximum Likelihood analyses using two nuclear (28S and H3) and two mitochondrial markers (16S and COI) for 210 individuals that represented 24 of the 29 families globally. Morphological phylogenies were estimated through Maximum Likelihood analyses of a morphological data matrix comprising 149 characters for 248 individuals that represent 24 families. The same data matrix was used to produce a key to all African mantodean families, accompanied by their descriptions.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202
An assessment of the status of psylloid species (Hemiptera: Psylloidea) as potential pests of commercial citrus in southern Africa: implications for pest management
Get PDFPsylloids (Hemiptera: Psylloidea), constitute a group of plant sap-sucking insects, some of which are economically significant pests in different ecosystems due to their potential to transmit Gram-negative bacteria, such as the Candidatus Liberibacter species. The African citrus triozid (ACT), Trioza erytreae (Del Guercio), which transmits African citrus greening and the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, which transmits Asian citrus greening are significant threats to citrus. Asian citrus psyllid poses a global economic threat due to its ability to vector “Candidatus Liberibacter asiaticus” (CLas), which can rapidly kill citrus trees. However, both ACP and CLas are currently not present in southern Africa but are present in East and West Africa. In the Afrotropical region, 71 triozid species are known to occur and approximately 41 described Diaphorina species in southern Africa. Currently, two indigenous Diaphorina species, Diaphorina punctulata and Diaphorina zebrana have been documented to feed on citrus. There is a significant knowledge gap regarding the ecological roles of other indigenous psylloid species occurring within the citrus environments. Therefore, this study aimed to: (i) determine the diversity and community structure of psylloid species in citrus environments, and (ii) their host ranges through DNA analysis of gut contents to determine if they fed on citrus. Field surveys were carried out across 12 distinct commercial citrus environments across Limpopo and Mpumalanga provinces between 2022 and 2023. Psylloids were collected using yellow sticky traps and an insect sweep-net. Collected psylloid specimens were preserved in 70% ethanol vials and identified to the lowest possible taxonomic level (i.e. genus or species) using both published and unpublished dichotomous identification keys. Furthermore, citrus leaf samples were collected from the same plants on which psylloids were found in the orchards. Genomic DNA (gDNA) was extracted from both leaf and psylloid samples using two different DNA extraction methods. To confirm if citrus DNA could be detected in the psylloid guts, all leaf gDNA samples were initially amplified using the rbcLaF/R primer pair, targeting a 530-bp region of the chloroplast rbcL gene through the polymerase chain reaction (PCR). Lastly, gut content analysis was performed on 11 psylloid species using the same primer pair through PCR to detect citrus DNA. A total of 4,900 psylloids belonging to five families (i.e. Aphalaridae, Carsidaridae, Liviidae, Psyllidae and Triozidae), 19 genera and 47 species, were collected in citrus environments. More psylloids were recorded in Limpopo (3,754) than in Mpumalanga (1,146). The most abundant species were Pauropsylla trichaeta (1,680), followed by Diaphorina punctulata (466), Trioza erytreae (426), Diaphorina virgata (371), Euryconus sp. (358), Cacopsylla sp. (311), Retroacizzia mopanei (263), Acizzia russellae-group (240), Acizzia sp.3 (216) and Acizzia sp.2 (140). Yellow sticky traps captured 3,265 psylloids in citrus orchards, while an insect sweep-net collected 1,635 psylloids (477 from citrus orchards and 1,158 from adjacent natural vegetation). Data from the insect sweep-net revealed that 22 psylloid species were recorded on citrus. In comparison, nine psylloid species were found on Vachellia spp. and unidentified plant species separately, whereas six, three and two psylloid species were recorded on marula, Ficus sp. and mopane, respectively. The abundance, richness and community structure of psylloids differed significantly between the collection methods, provinces and among plant species. The rbcLaF/R primer pair amplified all citrus leaf gDNA samples, producing amplicons of the targeted 530-bp size. The PCR analysis of 11 psylloid species showed that the rbcLaF/R primer pair amplified plant DNA, with PCR-amplified plant DNA samples producing amplicons between 500-bp and 750-bp in the gut contents of five psyllid species: Diaphorina punctulata, Diaphorina virgata, Diaphorina zebrana, Euryconus sp. and Trioza erytreae. However, the targeted 530-bp plant DNA region was only amplified from the gut contents of Euryconus sp. and Diaphorina punctulata. This study documented psylloid diversity and community structure within commercial citrus environments. The findings indicate that the community of psylloids was diverse in citrus environments, with yellow sticky traps being more effective in monitoring different psyllid species within these environments. Furthermore, the PCR analysis detected citrus DNA in the gut contents of Euryconus sp. and Diaphorina punctulata, suggesting that they could be nibbling on citrus when their specific or main host-plants adjacent to citrus orchards are depleted. However, these insects do not lay their eggs or complete their life cycle on citrus, further confirming that citrus is not their host-plant. Thus, further studies, including Sanger sequencing of PCR-amplified plant DNA, are recommended to confirm the ingested plant species, and host-specific testing including infection trials needs to be conducted.Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 202
Bio-vectoring by honeybees and symbiosis: a combined approach to controlling Botrytis mould on strawberry
No full textAccess restricted. Exxpected release in 2026.Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 202
Using in silico approaches to ascertain selective novel orthosteric and allosteric inhibitors of plasmodium falciparum Prolyl-tRNA synthetase for the development of antimalarial drugs
Get PDFAccess restricted. Exxpected release in 2026.Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 202
Investigating deep-seated factors that can condition English First Additional Language literature teaching in Grade 7
No full textAccess restricted. Expected release in 2026.Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes of Africa, 202
An analysis of tax incentives offered for investments by individuals in South Africa and the United Kingdom
Get PDFThis research analysed the tax incentives available for investments by individuals in South Africa and compared them to investments in the United Kingdom. It answered the question whether, based on incentives provided in the United Kingdom, recommendations can be made for investment incentives to be implemented in South Africa. The type of investments described were venture capital schemes, tax-free investments, retirement savings, endowment policies, purchased annuities, workplace investment schemes, and fixed interest bonds. These classes of investments were discussed together with the tax incentives offered for them in South Africa and the United Kingdom. An interpretative paradigm was adopted for this research, together with a doctrinal methodology and a qualitative method. This research analysed the legislative provisions in South Africa and the United Kingdom. Information was also collected from secondary sources such as textbooks and articles written on investments and taxes. There were no ethical considerations in this research as the data that was used are publicly available. The tax incentive provisions in South Africa have not proven to be effective in increasing household savings, which remain low. The comparison of the taxes and incentives in South Africa and the United Kingdom indicated that there are some similarities on how certain investments are taxed, but for most types of investments, the United Kingdom provided more favourable tax incentives than South Africa. Recommendations were made for the venture capital company incentive previously applying to be reinstated, or to introduce some form of income tax and capital gains tax relief for direct investment into venture capital companies. The removal of the penalty for tax-free investments in excess of the maximum permitted was recommended, and to charge income tax according to the tax tables on contributions exceeding the limit. With regard to purchased annuities, it was recommended that no income tax should apply to annuities received in the case of disability, sickness, and similar circumstances. For the section 8B Broad-Based Share Incentive Scheme recommendations were made to not levy dividends tax on cash dividends retained for reinvestment into the scheme, and for employees not to be liable for income tax when shares are disposed of, where they are no longer in the relevant employment due to circumstances beyond their control. A recommendation was also made to consider introducing workplace savings schemes similar to the savings schemes applying in the United Kingdom. An education campaign by the South African Revenue Service was recommended, to inform the public of investment incentives.Thesis (MCom) -- Faculty of Commerce, Accounting, 202
The stock market and the business cycle in South Africa
Get PDFThe relationship between the stock market and economic activity has long been a topic for research. Several studies done in both advanced and emerging economies including South Africa before COVID-19 found stock market prices predict the cycle of real economic activity and some found it to be the reversal. Therefore, this Study seeks to examine this topic and will extend beyond the post-covid period exploring the relationship between the stock market (proxied by the JSE All-Share Index) and the business cycle (represented by the Coincident Business Cycle Indicator of the SARB) in South Africa. The study also investigates if the relationship between the stock market and the business cycle is homogenous across the three selected sectors of the JSE using a combination of the “financial accelerator theory”, the “wealth effect theory”, the “traditional valuation model of stock prices”, the “stock prices as aggregators of expectations”, and the “cost of raising equity capital”. The Econometrics models employed include time-series and panel cointegration techniques, relying on the ARDL estimation model and a Granger-Causality Test. The findings of this study indicate that a long-run relationship exists between the stock market and the business cycle in South Africa. The findings support the notion that the stock market predicts economic activity, and this relationship is assumed to be homogenous across the selected Sectors of the JSE (namely, Resources, Financials, and Industrials). Again, the Granger-Causality Test confirms the relationship between the stock market and the business cycle in South Africa to be unidirectional. It is recommended that since the stock market affects South African economic activity positively in the long run which is consistent with findings of similar studies done on the JSE, the South African Reserve Bank (SARB) must strengthen existing policy to ensure financial system stability and sustainable economic growth in South Africa. Again, the stock market being a leading indicator of the business cycle is something different. As a recommendation, we need to look at ways to use the prediction ability in a business setting. Investors and Portfolio Managers can follow trends of the stock market to forecast the direction of the future economy to make educated decisions to hedge their investments and diversify their portfolios against huge losses in crises such as the Financial Crises and the Global Health Crisis (COVID-19), however, with the caveat that the stock market does not always accurately predict the business cycle.Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 202
The integration of sustainability in municipalities in South Africa: an evaluation of an Eastern Cape district municipality’s water supply distribution systems
Get PDFThe Constitution of the Republic of South Africa mandates municipalities to provide sustainable services to communities, particularly those responsible for water and sanitation. Despite this obligation, many communities in the Oliver Reginald Tambo District Municipality (ORTDM) face prolonged water interruptions due to challenges with infrastructure. This study has assessed the ORTDM’s efforts to integrate sustainability principles into its water supply distribution systems development programmes. Essentially, it aimed to evaluate whether and how ORTDM integrates social, environmental, economic, engineering, and project management sustainability principles into its developmental initiatives. Grounded in the backdrop of global sustainable development imperatives, particularly the Triple Bottom Line (TBL) concept, the research explored challenges and considerations within local government in pursuit of sustainability in water infrastructure development. Utilising a qualitative research approach within a post-positivism paradigm, the study employed semi-structured interviews and document analysis as primary data collection methods, emphasising triangulation for research validity and ethical considerations throughout the study. Although the initially planned sample size was 12 participants, the study successfully interviewed seven municipal officials from ORTDM’s water and sanitation services delivery department, achieving a participation rate of 58%, which aligns with qualitative research standards. Findings from document analysis and interviews were categorised based on identified sustainability principles, highlighting strategies adopted and challenges encountered by ORTDM, including opportunities available for ORTDM. The study reveals that while ORTDM has made efforts to integrate sustainability principles, numerous challenges, including financial and natural resource constraints, organisational capacity limitations, inadequate infrastructure planning and maintenance, and socio-economic challenges, have hindered desired outcomes. Additionally, issues like vandalism, theft, biodiversity loss, and fragmented water conservation strategies exacerbate sustainability integration challenges. To address these barriers, the study recommends prioritising management approaches to enhance sustainability integration in ORTDM’s water services. Drawing on resilience theory, the study further proposes integrating resilience principles into planning, design, and management processes to improve organisational and system resilience, thus ensuring reliable and sustainable water services. The study emphasises the importance of interdisciplinary collaboration and innovative solutions in achieving resilient, equitable, economical, and environmentally responsible water supply distribution systems.Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 202