Biology and management of the fruit piercing moth Serrodes partita in citrus orchards
- Authors: Mushore, Tapiwa Gift
- Date: 2024-10-11
- Subjects: Baculoviruses , Moths Monitoring , Pests Control , Insect traps , Citrus Diseases and pests South Africa Kat River Valley , Catapult moth
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466792 , vital:76779 , DOI https://doi.org/10.21504/10962/466792
- Description: The fruit-piercing moth, Serrodes partita (Fabricius) (Lepidoptera: Erebidae), is a polyphagous, multivoltine pest of citrus. This insect has a distinct geographical separation between its larval and adult stages, each with different feeding patterns. During the larval stage, it primarily acts as a forest defoliator, feeding mostly on Jacket plum, Pappea capensis Eckl. & Zeyh. (Sapindaceae). In contrast, the adult stage of this moth feeds on both tropical and subtropical fruit, including citrus and can cause serious economic losses. The adult moth uses its sclerotised proboscis to pierce the skin of ripening or ripe fruit, from which it extracts the juice. This piercing action initiates a fermentation process within the fruit, attracting other secondary-feeding moths, commonly referred to as fruit-sucking moths. As a result of the feeding activity, the affected fruit eventually rot, drop to the ground, and become unsuitable for the market. Serrodes partita exhibits an outbreak life strategy, reoccurring every 5 to 10 years. In South Africa's Eastern Cape Province, specifically in the Upper Kat River Valley, citrus growers have expressed concerns about the impact of this moth on soft citrus (Satsumas and Clementines). This raises the possibility of a shift in the population dynamics of S. partita, where these occurrences become more frequent and less sporadic. Such a trend poses a significant threat to fruit arboriculture in the Eastern Cape region. Currently, there are limited management strategies available for managing fruit-piecing moths. The use of pesticides is not a feasible option for ripe or nearly ripe fruit, and is ineffective against the adult moth. Alternative control methods, such as orchard netting and light barriers, either come with high costs or are impractical for large-scale citrus production. Given the limited range of management options, combined with the moth's tendency for sudden outbreaks, citrus growers find themselves without effective means to manage this pest. The objective of this study was, therefore, to investigate the biology of S. partita and explore various control options to effectively manage this pest. Research focused on the biology and laboratory rearing of larval stages of S. partita. The flight behaviour, feeding patterns, and preferences of adult S. partita within citrus orchards were also explored. The aim was to elucidate key fundamental aspects, including whether the same population frequents a particular orchard, and if infestations within orchards exhibit a specific direction. Lure type and lure presentation method trials were conducted to determine the most effective lure and trap design. Seasonal monitoring of S. partita in soft citrus orchards was conducted over three years to determine its outbreak status in the Committee’s Drift area and the role of weather variables in the activity of the moth. Damage assessments were also conducted alongside monitoring to determine the level of damage inflicted by S. partita. Natural enemies associated with S. partita were explored to determine the prevalence and causes of mortality in late instars during laboratory rearing. Rearing S. partita on an artificial diet was unsuccessful despite several modifications. The moth, however, completed its entire life cycle on its natural host, P. capensis in the laboratory. The total life cycle from egg to adult took 80.7 ± 3.6 days, the larval stage lasted 52.3 ± 2.8 days, and the pupal stage lasted 25.8 ± 3.6 days at 21°C. The investigation into the biology of S. partita also brought attention to the most susceptible stages of its growth, with high mortality rates recorded among neonates and late instars. The findings of the study revealed directional patterns of moth infestations, with higher numbers observed at the orchard's periphery leading towards natural vegetation. This raises the prospect of using sacrificial rows on the edge of a citrus orchard to concentrate moth feeding damage during outbreak years. Using a mark and recapture technique, the study showed that a relatively small proportion (4.5 %) of moths tended to revisit the same orchard. The moths strongly preferred damaged fruit (85 %) over undamaged fruit. Visible damage (rotting symptoms) typically became apparent within 3 to 5 days. Satsumas had a higher number of feeding scars (2.1) than Clementines (1.08), highlighting their susceptibility. The study also established that, on average, pierced soft citrus fruit takes about four days to display symptoms of decay. Synthetic proprietary Australian lures were ineffective at attracting the moth, whereas fresh bananas proved to be a successful lure. Furthermore, the addition of both Agar and Super absorbent polymer showed promise as thickening agents to enhance the longevity of fresh bananas in traps. The effectiveness of various trap designs was compared, including the funnel trap, delta trap, bucket trap, and circular trap, in capturing fruit-feeding moths. The funnel trap performed best as it captured the most moths, followed by the delta trap, Lynfield trap and disc trap, respectively. Additionally, an electronic enhancement to the funnel trap, incorporating a zapper element, improved efficiency. However, efforts to exploit both visual and olfactory cues through the inclusion of an Ultraviolet (UV) light component did not improve its effectiveness. No extensive outbreaks were recorded during the study; however, population variations of S. partita populations were recorded. Annual trends showed two population peaks, with the first peak recorded from December to March, while the second peak was recorded from April to July. The activity of the moths also differed across different months, with the highest peaks recorded in May, while no moths were recorded from August to November. Both cultivar type and farm location did not influence the occurrence of the moth. Meanwhile cumulative weather parameters (rainfall, temperature and humidity) from the four months prior to occurrence influenced the activity of S. partita. Temperature determined the timing of the outbreak, while rainfall determined the magnitude of the outbreak. Damage assessment showed very low fruit damage by S. partita throughout the monitoring period. Varying levels of infestation by a tachinid fly, 4 % and 35 %, were recorded for 2021 and 2022, respectively. The tachinid parasitoid could not be identified at the species level. A novel baculovirus, tentatively classified as S. partita NPV (SepaNPV), was identified as the larval mortality causative agent. This study enhanced our understanding of S. partita's biology and population dynamics, providing valuable insights for developing effective management strategies against this economically impactful citrus pest. Future research should focus on refining control measures and addressing the challenges of the adult moth's elusive nature. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mushore, Tapiwa Gift
- Date: 2024-10-11
- Subjects: Baculoviruses , Moths Monitoring , Pests Control , Insect traps , Citrus Diseases and pests South Africa Kat River Valley , Catapult moth
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466792 , vital:76779 , DOI https://doi.org/10.21504/10962/466792
- Description: The fruit-piercing moth, Serrodes partita (Fabricius) (Lepidoptera: Erebidae), is a polyphagous, multivoltine pest of citrus. This insect has a distinct geographical separation between its larval and adult stages, each with different feeding patterns. During the larval stage, it primarily acts as a forest defoliator, feeding mostly on Jacket plum, Pappea capensis Eckl. & Zeyh. (Sapindaceae). In contrast, the adult stage of this moth feeds on both tropical and subtropical fruit, including citrus and can cause serious economic losses. The adult moth uses its sclerotised proboscis to pierce the skin of ripening or ripe fruit, from which it extracts the juice. This piercing action initiates a fermentation process within the fruit, attracting other secondary-feeding moths, commonly referred to as fruit-sucking moths. As a result of the feeding activity, the affected fruit eventually rot, drop to the ground, and become unsuitable for the market. Serrodes partita exhibits an outbreak life strategy, reoccurring every 5 to 10 years. In South Africa's Eastern Cape Province, specifically in the Upper Kat River Valley, citrus growers have expressed concerns about the impact of this moth on soft citrus (Satsumas and Clementines). This raises the possibility of a shift in the population dynamics of S. partita, where these occurrences become more frequent and less sporadic. Such a trend poses a significant threat to fruit arboriculture in the Eastern Cape region. Currently, there are limited management strategies available for managing fruit-piecing moths. The use of pesticides is not a feasible option for ripe or nearly ripe fruit, and is ineffective against the adult moth. Alternative control methods, such as orchard netting and light barriers, either come with high costs or are impractical for large-scale citrus production. Given the limited range of management options, combined with the moth's tendency for sudden outbreaks, citrus growers find themselves without effective means to manage this pest. The objective of this study was, therefore, to investigate the biology of S. partita and explore various control options to effectively manage this pest. Research focused on the biology and laboratory rearing of larval stages of S. partita. The flight behaviour, feeding patterns, and preferences of adult S. partita within citrus orchards were also explored. The aim was to elucidate key fundamental aspects, including whether the same population frequents a particular orchard, and if infestations within orchards exhibit a specific direction. Lure type and lure presentation method trials were conducted to determine the most effective lure and trap design. Seasonal monitoring of S. partita in soft citrus orchards was conducted over three years to determine its outbreak status in the Committee’s Drift area and the role of weather variables in the activity of the moth. Damage assessments were also conducted alongside monitoring to determine the level of damage inflicted by S. partita. Natural enemies associated with S. partita were explored to determine the prevalence and causes of mortality in late instars during laboratory rearing. Rearing S. partita on an artificial diet was unsuccessful despite several modifications. The moth, however, completed its entire life cycle on its natural host, P. capensis in the laboratory. The total life cycle from egg to adult took 80.7 ± 3.6 days, the larval stage lasted 52.3 ± 2.8 days, and the pupal stage lasted 25.8 ± 3.6 days at 21°C. The investigation into the biology of S. partita also brought attention to the most susceptible stages of its growth, with high mortality rates recorded among neonates and late instars. The findings of the study revealed directional patterns of moth infestations, with higher numbers observed at the orchard's periphery leading towards natural vegetation. This raises the prospect of using sacrificial rows on the edge of a citrus orchard to concentrate moth feeding damage during outbreak years. Using a mark and recapture technique, the study showed that a relatively small proportion (4.5 %) of moths tended to revisit the same orchard. The moths strongly preferred damaged fruit (85 %) over undamaged fruit. Visible damage (rotting symptoms) typically became apparent within 3 to 5 days. Satsumas had a higher number of feeding scars (2.1) than Clementines (1.08), highlighting their susceptibility. The study also established that, on average, pierced soft citrus fruit takes about four days to display symptoms of decay. Synthetic proprietary Australian lures were ineffective at attracting the moth, whereas fresh bananas proved to be a successful lure. Furthermore, the addition of both Agar and Super absorbent polymer showed promise as thickening agents to enhance the longevity of fresh bananas in traps. The effectiveness of various trap designs was compared, including the funnel trap, delta trap, bucket trap, and circular trap, in capturing fruit-feeding moths. The funnel trap performed best as it captured the most moths, followed by the delta trap, Lynfield trap and disc trap, respectively. Additionally, an electronic enhancement to the funnel trap, incorporating a zapper element, improved efficiency. However, efforts to exploit both visual and olfactory cues through the inclusion of an Ultraviolet (UV) light component did not improve its effectiveness. No extensive outbreaks were recorded during the study; however, population variations of S. partita populations were recorded. Annual trends showed two population peaks, with the first peak recorded from December to March, while the second peak was recorded from April to July. The activity of the moths also differed across different months, with the highest peaks recorded in May, while no moths were recorded from August to November. Both cultivar type and farm location did not influence the occurrence of the moth. Meanwhile cumulative weather parameters (rainfall, temperature and humidity) from the four months prior to occurrence influenced the activity of S. partita. Temperature determined the timing of the outbreak, while rainfall determined the magnitude of the outbreak. Damage assessment showed very low fruit damage by S. partita throughout the monitoring period. Varying levels of infestation by a tachinid fly, 4 % and 35 %, were recorded for 2021 and 2022, respectively. The tachinid parasitoid could not be identified at the species level. A novel baculovirus, tentatively classified as S. partita NPV (SepaNPV), was identified as the larval mortality causative agent. This study enhanced our understanding of S. partita's biology and population dynamics, providing valuable insights for developing effective management strategies against this economically impactful citrus pest. Future research should focus on refining control measures and addressing the challenges of the adult moth's elusive nature. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
- Full Text:
- Date Issued: 2024-10-11
Border crossing, collecting, gravitating: small narratives of three ordinary collectors in the Chinese diaspora in South Africa since the late 1980s
- Authors: Grobbelaar, Binjun
- Date: 2024-10-11
- Subjects: Chinese diaspora , Art Collectors and collecting South Africa , Autobiography in art , Art History , Knowledge, Sociology of , Proximity
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467039 , vital:76809 , DOI https://doi.org/10.21504/10962/467039
- Description: Shifting away from the conventional viewpoint that confines art collecting predominantly to established structures like art institutions, markets, and exclusive collector networks, a trajectory historically influenced by Western collecting traditions and museology, this thesis takes a radical turn by delving into the small narratives of three ordinary Chinese collectors, namely Shengkai Wu, Yiyuan Yang and Shudi Li, who immigrated to South Africa since the late 1980s. The focus on Chinese collectors and migration resonates with my positionality as a recent Chinese immigrant in South Africa and aligns with Boaventura de Sousa Santos’s approach to proximity in knowledge-making, which emphasises ‘knowing with’ and ‘walking alongside’ the subjects of study. The selected immigrant collectors were chosen based on their current low-to-middle economic status in South Africa. These three individuals have decades of living and artcollecting experience in the country, having held professional backgrounds in China prior to their immigration. The number of collectors was determined through an in-depth qualitative biographical research method, taking into account the niche field of art collecting and the relatively small Chinese population within the broader South African demographic. It approaches collecting as a method of pursuing clues and explores it as a socio-cultural practice by collaging the biographies of three ordinary collectors as micro-histories. Details of these ordinary lives are entangled with the lives of objects that traverse China and South Africa. The use of non-official data, at times fragmented and partially obscured, is employed to craft a narrative that weaves together diverse and complex perspectives. The aim of this thesis is to attempt to shift from elite collecting narratives to a more diverse understanding of the global circulation and appropriation of art and cultural objects in relation to grassroots migration. This shift is explored through the unique insights derived from recovering the personal narratives of ordinary immigrant collectors and their associated objects in overlooked geographical locations and states of transformation within the context of China– Africa relations. I engage China–Africa relations within the framework Global South, seeks to address the limitations of describing the multi-dimensional interweaving of low-profile individual and objecthood, unofficial and official, historical and ephemeral relationships in the burgeoning field of China-Africa relations. The investigation unfolds through two interconnected aspects embedded in the development of each collector’s biography. Firstly, it delves into how the collecting practices of these three Chinese collectors are interwoven with their experiences in both China and South Africa. Secondly, it examines the agencies of the collectors and the relationships they establish with the objects they collect. I approach these collectors as curators of their autobiographical exhibitions in the process of preliminary data collection and subsequent thematic and object-oriented interviews. Through the analysis of collectors’ oral, visual and written narratives, as well as the biographies of objects, this PhD thesis in Art History uncovers a multilayered influx of crossways of knowledge-making by the collectors on the ground. Inspired by practical material re-ordering and personal interests, these collectors engage in configuring the border-crossing process within the Chinese diaspora in South Africa. Recurring narratives of critical socialist experiences in Maoist China are linked to their suppressed agency and subsequent recovery through emigration to South Africa. They negotiate a complex diasporic terrain marked by engaging with socialist philately materials, persistently gravitating towards China. Concurrently, they transcend conventional nation-state framework, accentuating the convergent aesthetic qualities inherent in transnational artefacts and community-based art practices. The collectors’ engagement with exported Chinese “specialised arts and crafts”, and unconventional artefacts, such as philately materials, creates a bottom-up fresh interpretation of what constitutes collecting Chinese art in the context of South Africa. Fragments of British colonial history on the Rand, Chinese semi-colonial history, and contemporary printmaking in both China and South Africa, embedded in tangible material artefacts and in intangible visual connection, become visible through their logics of collecting and affective approach from the bottom up. Highlighting the often-overlooked Chinese agency in the creation of these objects, this research illustrates how individual mobility between China and Africa can contribute to the nuanced role of aesthetics through collecting, redefining what is visible and meaningful in the context of the Chinese diaspora and art collecting in South Africa. Specifically, discourses on the border poetics of Zheng He, colonial postcards and notices on the Rand, visual connection in printmaking, and Chinese semi-colonial artefacts of a converged “Chinese–British” aesthetic and a controversial Tang blue-and-white dish are instances where ordinary Chinese collectors in the Global South strategically mobilise collecting as a means to migrate towards an alternative politics of hope, as conceptualised by Chiara Brambilla. This hope presents a “strategic Southerness,” cultivates an “alter-geopolitics of knowledge” (Simbao 2017) that, pushing against the often-dominant representation of spectacle within the structured frameworks of art institutions, markets and networks of elite collectors. I argue that these emerging themes and objects in the collectors’ narratives represent a grounded, localised knowledge-making from below, unfolding practices underpinned by the material conditions of ordinary collectors of art and material culture in the Global South, aspects that have not been given adequate attention in history. In the process of encountering, reassembling, and appropriating these material objects and associating people in South Africa, I argue that collecting becomes not only an act of diasporic agency in constructing memories of the past, but also offers insight into the complex Chinese diaspora within the dynamics of a rising Chinese presence in Africa. On the one hand, these ordinary collectors employ collecting as an act of resistance against the aftermath of political turmoil and the epistemological inequality imposed on grassroots communities. Their emergence has contributed to transforming the residual colonial culture of the “othering” in the landscape of art collecting in South Africa. On the other hand, their agency intersects with Chinese diasporic nationalism, which lingers in the tension between internalised Eurocentric exploitation and romanticised appreciation and cultural preservation, a question that awaits for further investigation. , Thesis (PhD) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Grobbelaar, Binjun
- Date: 2024-10-11
- Subjects: Chinese diaspora , Art Collectors and collecting South Africa , Autobiography in art , Art History , Knowledge, Sociology of , Proximity
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/467039 , vital:76809 , DOI https://doi.org/10.21504/10962/467039
- Description: Shifting away from the conventional viewpoint that confines art collecting predominantly to established structures like art institutions, markets, and exclusive collector networks, a trajectory historically influenced by Western collecting traditions and museology, this thesis takes a radical turn by delving into the small narratives of three ordinary Chinese collectors, namely Shengkai Wu, Yiyuan Yang and Shudi Li, who immigrated to South Africa since the late 1980s. The focus on Chinese collectors and migration resonates with my positionality as a recent Chinese immigrant in South Africa and aligns with Boaventura de Sousa Santos’s approach to proximity in knowledge-making, which emphasises ‘knowing with’ and ‘walking alongside’ the subjects of study. The selected immigrant collectors were chosen based on their current low-to-middle economic status in South Africa. These three individuals have decades of living and artcollecting experience in the country, having held professional backgrounds in China prior to their immigration. The number of collectors was determined through an in-depth qualitative biographical research method, taking into account the niche field of art collecting and the relatively small Chinese population within the broader South African demographic. It approaches collecting as a method of pursuing clues and explores it as a socio-cultural practice by collaging the biographies of three ordinary collectors as micro-histories. Details of these ordinary lives are entangled with the lives of objects that traverse China and South Africa. The use of non-official data, at times fragmented and partially obscured, is employed to craft a narrative that weaves together diverse and complex perspectives. The aim of this thesis is to attempt to shift from elite collecting narratives to a more diverse understanding of the global circulation and appropriation of art and cultural objects in relation to grassroots migration. This shift is explored through the unique insights derived from recovering the personal narratives of ordinary immigrant collectors and their associated objects in overlooked geographical locations and states of transformation within the context of China– Africa relations. I engage China–Africa relations within the framework Global South, seeks to address the limitations of describing the multi-dimensional interweaving of low-profile individual and objecthood, unofficial and official, historical and ephemeral relationships in the burgeoning field of China-Africa relations. The investigation unfolds through two interconnected aspects embedded in the development of each collector’s biography. Firstly, it delves into how the collecting practices of these three Chinese collectors are interwoven with their experiences in both China and South Africa. Secondly, it examines the agencies of the collectors and the relationships they establish with the objects they collect. I approach these collectors as curators of their autobiographical exhibitions in the process of preliminary data collection and subsequent thematic and object-oriented interviews. Through the analysis of collectors’ oral, visual and written narratives, as well as the biographies of objects, this PhD thesis in Art History uncovers a multilayered influx of crossways of knowledge-making by the collectors on the ground. Inspired by practical material re-ordering and personal interests, these collectors engage in configuring the border-crossing process within the Chinese diaspora in South Africa. Recurring narratives of critical socialist experiences in Maoist China are linked to their suppressed agency and subsequent recovery through emigration to South Africa. They negotiate a complex diasporic terrain marked by engaging with socialist philately materials, persistently gravitating towards China. Concurrently, they transcend conventional nation-state framework, accentuating the convergent aesthetic qualities inherent in transnational artefacts and community-based art practices. The collectors’ engagement with exported Chinese “specialised arts and crafts”, and unconventional artefacts, such as philately materials, creates a bottom-up fresh interpretation of what constitutes collecting Chinese art in the context of South Africa. Fragments of British colonial history on the Rand, Chinese semi-colonial history, and contemporary printmaking in both China and South Africa, embedded in tangible material artefacts and in intangible visual connection, become visible through their logics of collecting and affective approach from the bottom up. Highlighting the often-overlooked Chinese agency in the creation of these objects, this research illustrates how individual mobility between China and Africa can contribute to the nuanced role of aesthetics through collecting, redefining what is visible and meaningful in the context of the Chinese diaspora and art collecting in South Africa. Specifically, discourses on the border poetics of Zheng He, colonial postcards and notices on the Rand, visual connection in printmaking, and Chinese semi-colonial artefacts of a converged “Chinese–British” aesthetic and a controversial Tang blue-and-white dish are instances where ordinary Chinese collectors in the Global South strategically mobilise collecting as a means to migrate towards an alternative politics of hope, as conceptualised by Chiara Brambilla. This hope presents a “strategic Southerness,” cultivates an “alter-geopolitics of knowledge” (Simbao 2017) that, pushing against the often-dominant representation of spectacle within the structured frameworks of art institutions, markets and networks of elite collectors. I argue that these emerging themes and objects in the collectors’ narratives represent a grounded, localised knowledge-making from below, unfolding practices underpinned by the material conditions of ordinary collectors of art and material culture in the Global South, aspects that have not been given adequate attention in history. In the process of encountering, reassembling, and appropriating these material objects and associating people in South Africa, I argue that collecting becomes not only an act of diasporic agency in constructing memories of the past, but also offers insight into the complex Chinese diaspora within the dynamics of a rising Chinese presence in Africa. On the one hand, these ordinary collectors employ collecting as an act of resistance against the aftermath of political turmoil and the epistemological inequality imposed on grassroots communities. Their emergence has contributed to transforming the residual colonial culture of the “othering” in the landscape of art collecting in South Africa. On the other hand, their agency intersects with Chinese diasporic nationalism, which lingers in the tension between internalised Eurocentric exploitation and romanticised appreciation and cultural preservation, a question that awaits for further investigation. , Thesis (PhD) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
Burgernomics: Raw BMI vs Adjusted BMI. A comparative analysis of appropriate exchange rate valuation measures
- Gumedze, Siyanda Nakiwe Nomfundo
- Authors: Gumedze, Siyanda Nakiwe Nomfundo
- Date: 2024-10-11
- Subjects: Big Mac Index , Purchasing power parity , Foreign exchange rates , Foreign exchange market , Economic theory
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462702 , vital:76327
- Description: The Big Mac Index was developed in 1986 by The Economist magazine as a playful take on the Purchasing Power Parity theory. Its purpose is to indicate whether a currency is overpriced or undervalued in relation to the real exchange rate and whether it can be used as a reliable indicator of exchange rate predictions. There are two versions of the Big Mac Index: the raw Big Mac Index and the adjusted Big Mac Index. If appropriate, this index might be developed into an economic theory that can be applied to corporate finance, international trade, and international finance. To determine which Big Mac Index measure is a better indicator of exchange rate valuation, a comparison analysis was conducted. This study set out to determine how well the adjusted Big Mac Index performed as a gauge for exchange rate valuation. The research then compares the two Big Mac Index measures' ability to anticipate future exchange rates in order to determine which is more accurate. Data from the South African Reserve Bank and The Economist databases covering 37 nations from 2000 to 2022 were used for the analysis. Exchange rate misalignment trends were assessed globally, and the results indicated that the adjusted BMI was a more accurate measure of purchasing power. Tests of correlation revealed that there was a positive association between the real exchange rate and the Big Mac Index. Findings from a panel ARDL Model indicated that taking into consideration country-specific GDP variations and group heterogeneity can enhance the real exchange rates' ability to predict the raw BMI. The research also focused on the South African Rand to ascertain whether the Big Mac Index validates the Purchasing Power Parity theoretical framework. Using cointegration tests and graphic analysis, it was possible to find evidence for a cointegrating relationship between the real exchange rate and the Big Mac Index measures during the last 20 years. Additionally, a positive correlation between the modified Big Mac Index and terms of trade was discovered in the results, confirming the hypothesis that the Big Mac Index satisfies current account assumptions. Finally, a VEC model demonstrated that the modified BMI outperforms the raw BMI in terms of forecasting estimates. Overall, the study found that the Big Mac Index is more than a bit of fun as per its origin. The results showed that the adjusted Big Mac Index has practical applications and the potential to be considered as an economic theory. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Gumedze, Siyanda Nakiwe Nomfundo
- Date: 2024-10-11
- Subjects: Big Mac Index , Purchasing power parity , Foreign exchange rates , Foreign exchange market , Economic theory
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462702 , vital:76327
- Description: The Big Mac Index was developed in 1986 by The Economist magazine as a playful take on the Purchasing Power Parity theory. Its purpose is to indicate whether a currency is overpriced or undervalued in relation to the real exchange rate and whether it can be used as a reliable indicator of exchange rate predictions. There are two versions of the Big Mac Index: the raw Big Mac Index and the adjusted Big Mac Index. If appropriate, this index might be developed into an economic theory that can be applied to corporate finance, international trade, and international finance. To determine which Big Mac Index measure is a better indicator of exchange rate valuation, a comparison analysis was conducted. This study set out to determine how well the adjusted Big Mac Index performed as a gauge for exchange rate valuation. The research then compares the two Big Mac Index measures' ability to anticipate future exchange rates in order to determine which is more accurate. Data from the South African Reserve Bank and The Economist databases covering 37 nations from 2000 to 2022 were used for the analysis. Exchange rate misalignment trends were assessed globally, and the results indicated that the adjusted BMI was a more accurate measure of purchasing power. Tests of correlation revealed that there was a positive association between the real exchange rate and the Big Mac Index. Findings from a panel ARDL Model indicated that taking into consideration country-specific GDP variations and group heterogeneity can enhance the real exchange rates' ability to predict the raw BMI. The research also focused on the South African Rand to ascertain whether the Big Mac Index validates the Purchasing Power Parity theoretical framework. Using cointegration tests and graphic analysis, it was possible to find evidence for a cointegrating relationship between the real exchange rate and the Big Mac Index measures during the last 20 years. Additionally, a positive correlation between the modified Big Mac Index and terms of trade was discovered in the results, confirming the hypothesis that the Big Mac Index satisfies current account assumptions. Finally, a VEC model demonstrated that the modified BMI outperforms the raw BMI in terms of forecasting estimates. Overall, the study found that the Big Mac Index is more than a bit of fun as per its origin. The results showed that the adjusted Big Mac Index has practical applications and the potential to be considered as an economic theory. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
- Full Text:
- Date Issued: 2024-10-11
Carbonylation of cyclohexene with carbon dioxide (CO2) using transition metals as heterogeneous and homogeneous catalysts
- Authors: Sekaleli, Bafokeng Thabelo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464565 , vital:76522
- Description: From a green chemistry perspective, carbon dioxide (CO2) emerges as an appealing C1 synthon, given its abundance in the atmosphere and cost-effectiveness. Many essential chemicals for daily life are derived from fossilized carbon sources like coal, petroleum, and natural gas. However, the by-product of these processes, CO2, poses environmental risks when excessively emitted as a greenhouse gas. Achieving a balance between carbon emissions and removal is crucial to address environmental concerns surrounding CO2. Utilizing CO2 as a C1 source in organic synthesis holds promise for mitigating this balance in the long term. Combining CO2 with other underutilized fine chemicals, such as alkanes, alkenes, and alkynes, to produce more valuable platform chemicals presents an economically viable strategy due to carbon dioxide’s abundance, low cost, and recyclability. Despite its simplicity, CO2's high thermodynamic stability and low kinetic reactivity, owing to its highly oxidized state, pose challenges to its use as a feedstock. Overcoming these hurdles requires catalysts to enhance CO2 reactivity. Our work focuses on developing and employing catalytic systems capable of activating CO2 as a C1 synthon in reactions with cyclohexene and a reducing agent to yield carboxylic acids or esters. In one approach, we have developed heterogeneous catalyst systems comprising transition metals (Au, Fe, Ni, Ru) supported on metal oxide (TiO2). Characterization techniques such as TEM, EDX, UV-Vis, BET, and XRD were used to study the properties of these materials. The catalysts were evaluated in a reaction involving cyclohexene, CO2, and H2O. In another approach, we explored the use of cyclo-tris(tetracarbonylruthenium) [Ru3(CO)12] as a homogeneous catalyst in a reaction involving cyclohexene, methanol, and CO2 in the presence of an ionic liquid, 1-Butyl-3-methylimidazolium chloride ([BMIM]+Cl-). 1H NMR and ATR-FT-IR were utilized to characterize [BMIM]+Cl-. The reaction product was characterised utilizing GC-MS. Upon seeing that Ru3(CO)12 changes color from orange to black when exposed to heat, an investigation was undertaken on the kind of transformations that the catalyst undergoes. This investigation was carried out with the hopes of finding the structures that could be resulting from Ru3(CO)12 during the reaction and their significance to it. The orange and black Ru complexes were characterized utilizing DSC, TGA, ATR-FT-IR and PXRD. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Sekaleli, Bafokeng Thabelo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464565 , vital:76522
- Description: From a green chemistry perspective, carbon dioxide (CO2) emerges as an appealing C1 synthon, given its abundance in the atmosphere and cost-effectiveness. Many essential chemicals for daily life are derived from fossilized carbon sources like coal, petroleum, and natural gas. However, the by-product of these processes, CO2, poses environmental risks when excessively emitted as a greenhouse gas. Achieving a balance between carbon emissions and removal is crucial to address environmental concerns surrounding CO2. Utilizing CO2 as a C1 source in organic synthesis holds promise for mitigating this balance in the long term. Combining CO2 with other underutilized fine chemicals, such as alkanes, alkenes, and alkynes, to produce more valuable platform chemicals presents an economically viable strategy due to carbon dioxide’s abundance, low cost, and recyclability. Despite its simplicity, CO2's high thermodynamic stability and low kinetic reactivity, owing to its highly oxidized state, pose challenges to its use as a feedstock. Overcoming these hurdles requires catalysts to enhance CO2 reactivity. Our work focuses on developing and employing catalytic systems capable of activating CO2 as a C1 synthon in reactions with cyclohexene and a reducing agent to yield carboxylic acids or esters. In one approach, we have developed heterogeneous catalyst systems comprising transition metals (Au, Fe, Ni, Ru) supported on metal oxide (TiO2). Characterization techniques such as TEM, EDX, UV-Vis, BET, and XRD were used to study the properties of these materials. The catalysts were evaluated in a reaction involving cyclohexene, CO2, and H2O. In another approach, we explored the use of cyclo-tris(tetracarbonylruthenium) [Ru3(CO)12] as a homogeneous catalyst in a reaction involving cyclohexene, methanol, and CO2 in the presence of an ionic liquid, 1-Butyl-3-methylimidazolium chloride ([BMIM]+Cl-). 1H NMR and ATR-FT-IR were utilized to characterize [BMIM]+Cl-. The reaction product was characterised utilizing GC-MS. Upon seeing that Ru3(CO)12 changes color from orange to black when exposed to heat, an investigation was undertaken on the kind of transformations that the catalyst undergoes. This investigation was carried out with the hopes of finding the structures that could be resulting from Ru3(CO)12 during the reaction and their significance to it. The orange and black Ru complexes were characterized utilizing DSC, TGA, ATR-FT-IR and PXRD. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Care as dissent in the art of Georgina Maxim, Gladys Kalichini, Kresiah Mukwazhi, Masimba Hwati and Léonard Pongo
- Authors: Muchemwa, Fadzai Veronica
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466049 , vital:76680
- Description: The concept of care is proposed as an ethical and practical framework for the reading of the artistic and writing practices of Georgina Maxim, Kresiah Mukwazhi, Gladys Kalichini, Léonard Pongo and Masimba Hwati. In their practices, dissent is both an existential crisis and a constitutive practice. Through small actions, they offer up new narratives. The notion of seeing care as a form of dissent is to simply reflect on the artistic practices that are integrated with or responsive to forms of political protest and dissent based on ethical care practices and what it means to align with those things that matter to us and distancing ourselves from those things that do not. The thesis explores the ethic of care, its possibilities as a dissenting approach, and provides a narrative description of five case studies that exhibit different expressions of care in contemporary art. By prioritising care, there is an educational interest in creating resources and themes for a politically engaged approach to artistic practice and the creation of art. This study also aims to shed light on the power of art as a tool for social and political commentary, and the role of artists as agents of change in society. The study focuses on how these artists use their art to challenge societal norms and political structures, embodying the concept of care as a form of resistance. It underscores the importance of understanding the context in which art is created and the messages it conveys, particularly in societies where freedom of expression may be constrained. The study further investigates how these elements are presented in different ways to show the different manifestations of care and dissent. Through semi-structured interviews, analysis of relevant texts, and a detailed visual analysis of selected works from the five artists, the situational approach was used to explore how meanings are negotiated. The outcome is an expanded proposal for care as dissent and a listening guide as a tool or approach in helping us to listen to marginalised voices, validate experiences, identify barriers and building empathy. , Thesis (MA) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Muchemwa, Fadzai Veronica
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466049 , vital:76680
- Description: The concept of care is proposed as an ethical and practical framework for the reading of the artistic and writing practices of Georgina Maxim, Kresiah Mukwazhi, Gladys Kalichini, Léonard Pongo and Masimba Hwati. In their practices, dissent is both an existential crisis and a constitutive practice. Through small actions, they offer up new narratives. The notion of seeing care as a form of dissent is to simply reflect on the artistic practices that are integrated with or responsive to forms of political protest and dissent based on ethical care practices and what it means to align with those things that matter to us and distancing ourselves from those things that do not. The thesis explores the ethic of care, its possibilities as a dissenting approach, and provides a narrative description of five case studies that exhibit different expressions of care in contemporary art. By prioritising care, there is an educational interest in creating resources and themes for a politically engaged approach to artistic practice and the creation of art. This study also aims to shed light on the power of art as a tool for social and political commentary, and the role of artists as agents of change in society. The study focuses on how these artists use their art to challenge societal norms and political structures, embodying the concept of care as a form of resistance. It underscores the importance of understanding the context in which art is created and the messages it conveys, particularly in societies where freedom of expression may be constrained. The study further investigates how these elements are presented in different ways to show the different manifestations of care and dissent. Through semi-structured interviews, analysis of relevant texts, and a detailed visual analysis of selected works from the five artists, the situational approach was used to explore how meanings are negotiated. The outcome is an expanded proposal for care as dissent and a listening guide as a tool or approach in helping us to listen to marginalised voices, validate experiences, identify barriers and building empathy. , Thesis (MA) -- Faculty of Humanities, Fine Art, 2024
- Full Text:
- Date Issued: 2024-10-11
Carnivory submerged: aspects of the ecology and ecophysiology of the aquatic Utricularia stellaris L. fil. (Lentibulariaceae) in South Africa
- Authors: Marais, Alice-Jane
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464473 , vital:76514
- Description: The trapping structures produced by aquatic species of Utricularia have traditionally been interpreted to function as adaptations to capture and break down zooplankton prey, as in other carnivorous plants, to overcome nutrient limitations. However, an increasing number of studies have found that these plants may also rely on benefits derived from living mutualistic microbial communities contained within traps. This study documents aspects of the environmental, growth and physiological characteristics of U. stellaris to inform and to form a basis for future investigation into the plant-microbe interaction. The environmental conditions in which U. stellaris grows were documented to identify potential adverse conditions plants are subject to in situ, from which nutrient limitation was identified as a primary limitation. Plant growth and trapping structures were then assessed to identify possible adaptations of plants to overcome these limitations. The production of trapping structures likely constitutes an adaptive trait, with 30% of total biomass per node allocated to the production of these structures. Based on their capture function, traps may aid plants based on their contents, possibly supplementing plants with nutrients. Although assessments of the habitats of U. stellaris indicate that dissolved CO₂ concentrations in the ambient water are high, CO₂ may still be limiting to the photosynthetic rates of these plants due to viscous water resisting the diffusion of CO₂. The primary site of photosynthesis in U. stellaris is leaves and trap tissue’s contribution to photosynthetic output is negligible. U. stellaris plants are subject to CO₂ limitations in natural pond conditions, making the substantial allocation of resources to non-photosynthetic trapping tissue even more costly. Therefore, benefits gained from trapping structures are likely to be derived from trap contents; having ruled out the possibility that the trap tissue itself is photosynthetic. Trap contents of U. stellaris were assessed. The proportion of traps containing living microbial communities greatly exceeded the proportion containing zooplankton prey. In addition, these communities were found to be diverse, stable, and self-sustaining. These results suggest that trapping structures may be beneficial for both the carnivorous capture of prey and the housing of living microbial communities. These results indicate the plantmicrobe interaction in U. stellaris warrants further study. , Thesis (MSc) -- Faculty of Science, Botany, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Marais, Alice-Jane
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464473 , vital:76514
- Description: The trapping structures produced by aquatic species of Utricularia have traditionally been interpreted to function as adaptations to capture and break down zooplankton prey, as in other carnivorous plants, to overcome nutrient limitations. However, an increasing number of studies have found that these plants may also rely on benefits derived from living mutualistic microbial communities contained within traps. This study documents aspects of the environmental, growth and physiological characteristics of U. stellaris to inform and to form a basis for future investigation into the plant-microbe interaction. The environmental conditions in which U. stellaris grows were documented to identify potential adverse conditions plants are subject to in situ, from which nutrient limitation was identified as a primary limitation. Plant growth and trapping structures were then assessed to identify possible adaptations of plants to overcome these limitations. The production of trapping structures likely constitutes an adaptive trait, with 30% of total biomass per node allocated to the production of these structures. Based on their capture function, traps may aid plants based on their contents, possibly supplementing plants with nutrients. Although assessments of the habitats of U. stellaris indicate that dissolved CO₂ concentrations in the ambient water are high, CO₂ may still be limiting to the photosynthetic rates of these plants due to viscous water resisting the diffusion of CO₂. The primary site of photosynthesis in U. stellaris is leaves and trap tissue’s contribution to photosynthetic output is negligible. U. stellaris plants are subject to CO₂ limitations in natural pond conditions, making the substantial allocation of resources to non-photosynthetic trapping tissue even more costly. Therefore, benefits gained from trapping structures are likely to be derived from trap contents; having ruled out the possibility that the trap tissue itself is photosynthetic. Trap contents of U. stellaris were assessed. The proportion of traps containing living microbial communities greatly exceeded the proportion containing zooplankton prey. In addition, these communities were found to be diverse, stable, and self-sustaining. These results suggest that trapping structures may be beneficial for both the carnivorous capture of prey and the housing of living microbial communities. These results indicate the plantmicrobe interaction in U. stellaris warrants further study. , Thesis (MSc) -- Faculty of Science, Botany, 2024
- Full Text:
- Date Issued: 2024-10-11
Characterisation, and remote sensing exploration potential, of a hydrothermally mineralised Diorite, Chris Hani district, Eastern Cape, South Africa
- Authors: Johnstone, Shawn Douglas
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464930 , vital:76558
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Johnstone, Shawn Douglas
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464930 , vital:76558
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Geology, 2024
- Full Text:
- Date Issued: 2024-10-11
Church music as pedagogy: An investigation through digital storytelling into the role that Southern African Christian Church music praxis played in the musical development of five professional musicians
- Authors: Mathebula, Praise Ntsako
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465975 , vital:76673
- Description: Using an ethnographic and autoethnographic approach, this study investigated how the church has influenced the development and practice of five professional musicians practicing in South Africa. This research resulted from discussions with numerous musicians who had their music genesis at church, some of them well-known professionals in the country. Reflecting on the history of church music education that can be traced back to the arrival of the missionaries on the African continent and the different types of music education settings that can be found in South Africa, this thesis analyses the approach and delivery of music pedagogy that exists in the South African church setting. Discussing the introduction of Western musical tools such as tonic-solfa, choral music and four-part singing, this research contextualises the historical effect of mission education of several South African composers, including Tiyo Soga, Enoch Sontonga and John Knox Bokwe. Thereafter, using Digital Storytelling (DS) as a methodology for data collection and Ethnographic Content Analysis (ECA) as an analytic tool, co-researchers were given the opportunity to create data or share their stories in a novel manner, which has proven to develop powerful, honest and self-reflexive results. Important pedagogic themes that emerged as being part of a shared church-led approach to music teaching and learning include practice and consistent performance; collaboration; imitation; embodied and experiential learning, rote learning, and memorisation. Central to using DS as a methodology, this study found that musical identity and early pedagogical approaches to learning music play an important factor in further musical development and education. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mathebula, Praise Ntsako
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465975 , vital:76673
- Description: Using an ethnographic and autoethnographic approach, this study investigated how the church has influenced the development and practice of five professional musicians practicing in South Africa. This research resulted from discussions with numerous musicians who had their music genesis at church, some of them well-known professionals in the country. Reflecting on the history of church music education that can be traced back to the arrival of the missionaries on the African continent and the different types of music education settings that can be found in South Africa, this thesis analyses the approach and delivery of music pedagogy that exists in the South African church setting. Discussing the introduction of Western musical tools such as tonic-solfa, choral music and four-part singing, this research contextualises the historical effect of mission education of several South African composers, including Tiyo Soga, Enoch Sontonga and John Knox Bokwe. Thereafter, using Digital Storytelling (DS) as a methodology for data collection and Ethnographic Content Analysis (ECA) as an analytic tool, co-researchers were given the opportunity to create data or share their stories in a novel manner, which has proven to develop powerful, honest and self-reflexive results. Important pedagogic themes that emerged as being part of a shared church-led approach to music teaching and learning include practice and consistent performance; collaboration; imitation; embodied and experiential learning, rote learning, and memorisation. Central to using DS as a methodology, this study found that musical identity and early pedagogical approaches to learning music play an important factor in further musical development and education. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
Co-creating a pedagogy of care for our hydrocommons in South Africa
- Authors: Martin, Aaniyah
- Date: 2024-10-11
- Subjects: Teaching Social aspects , Reparations for historical injustices South Africa , Posthumanism , Creation (Literary, artistic, etc.) , Feminism and higher education , Social justice , Environmental justice
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466418 , vital:76726 , DOI https://doi.org/10.21504/10962/466418
- Description: My research focuses on watery relations in a South African context. Our planet, predominantly covered by water, relies on healthy oceans to sustain life by producing oxygen. Oceans, rivers, and wetlands constitute our natural water resources, integral to the hydrological cycle, collectively forming what Neimanis (2009) terms as hydrocommons. Hydrocommons encompass the shared water bodies and resources vital for human and more-than-human inhabitants alike. Caring for our hydrocommons is imperative for the well-being of the planet and all its inhabitants. Yet, the notion of responsibility for their upkeep sparks debate, as it intertwines with concepts of justice, extensively explored in academic discourse (Bozalek & Zembylas 2023). In South Africa, historical patterns of privilege tied to skin colour significantly influence perceptions of responsibility and care. This doctoral research engages with the enduring impacts of the apartheid legacy, which continues to shape notions of belonging, especially for Black and Brown South Africans who were forcibly displaced and restricted from accessing various areas, including urban spaces and natural environments such as beaches and game reserves. My perspective stems from my background as a scientist in the conservation field for over two decades, and transitioning into an educational doctorate with an emphasis on feminist, posthumanist, and care frameworks to address environmental and social justice concerns. Furthermore, I am a Brown Creole woman who was raised as a Muslim in Camissa, South Africa. The overarching question this dissertation seeks to address is; How can reparative care pedagogies reshape the hydrocommons for Black and Brown communities in post-apartheid South Africa? In order to respond to this question, I think diffractively with theory from feminism(s), posthumanism, research-creation and Slow scholarship - all of these are predicated on relational ontologies which embrace diverse ways of knowledge production in caring and meaning-making ways (Springgay & Truman, 2018; Stengers, 2011; Taylor et al, 2020). The research question I have posed is addressed through two key methods of enquiry namely strandlooping (beach walking) and hydro-rugging (stitching and mending). While there has been some literature on walking and mending methodologies from Northern contexts, I have opted to contextualise them within a South African framework with indigenous origins. By developing such methodologies in the local context, I aim to understand their application and relevance within South Africa's diverse cultural and environmental landscape. I have deliberately incorporated indigenous perspectives and practices in order to contribute to a more holistic and nuanced exploration of watery relations through iterative and collaborative events with participants. Chapter One provides an overview of my positionality and research practice by giving voice to those who have been marginalised, silenced and erased for three decades. The 30th anniversary for our first democratic elections was celebrated on the 27th April 2024 whilst I have been finalising my manuscript. The silence and erasure persist today, even though apartheid laws and regulations are no longer in effect. This lingering silence continues to permeate our lives and linger as a haunting presence. Consequently, strandlooping and hydro-rugging emerge as methods of enquiry that foster and provide avenues for care and healing. Chapter Two shares the stories of four Brown bodies and a tidal pool each of whom have a relationship with False Bay. The chapter shows how watery stories are shared through the process of hydro-rugging at the tidal pools. Chapter Three unravels the practice of strandlooping and develops propositions or watermarks to assist other researchers with this practice in their own contexts. Chapter Four articulates hydro-rugging as a method of enquiry and elucidates how the individual hydro-rugs are stitched alongside each other to create the Mother Hydro-rug. Chapter Five introduces three experiential research-creation events with fourth year students to meander and learn from them with regards to care for our hydrocommons. Drawing on relational ways of understanding and engaging with the world, this research culminates in several key implications for reparative care pedagogies in reshaping the hydrocommons. It underscores the importance of not only acknowledging but including diverse modes of knowledge and existence, particularly within Black and Brown communities marginalised by apartheid's racial and ethnic divisions. Additionally, it highlights the significance of challenging traditional educational paradigms entrenched in colonial and apartheid legacies. By prioritising embodied, experiential, and inclusive methodologies, the doctoral thesis advocates for a pedagogical shift toward relationality and process-oriented learning. This thesis prompts a reevaluation of extractive and exploitative educational practices, advocating instead for conviviality and the exploration of relational and embodied meanings and approaches. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Martin, Aaniyah
- Date: 2024-10-11
- Subjects: Teaching Social aspects , Reparations for historical injustices South Africa , Posthumanism , Creation (Literary, artistic, etc.) , Feminism and higher education , Social justice , Environmental justice
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466418 , vital:76726 , DOI https://doi.org/10.21504/10962/466418
- Description: My research focuses on watery relations in a South African context. Our planet, predominantly covered by water, relies on healthy oceans to sustain life by producing oxygen. Oceans, rivers, and wetlands constitute our natural water resources, integral to the hydrological cycle, collectively forming what Neimanis (2009) terms as hydrocommons. Hydrocommons encompass the shared water bodies and resources vital for human and more-than-human inhabitants alike. Caring for our hydrocommons is imperative for the well-being of the planet and all its inhabitants. Yet, the notion of responsibility for their upkeep sparks debate, as it intertwines with concepts of justice, extensively explored in academic discourse (Bozalek & Zembylas 2023). In South Africa, historical patterns of privilege tied to skin colour significantly influence perceptions of responsibility and care. This doctoral research engages with the enduring impacts of the apartheid legacy, which continues to shape notions of belonging, especially for Black and Brown South Africans who were forcibly displaced and restricted from accessing various areas, including urban spaces and natural environments such as beaches and game reserves. My perspective stems from my background as a scientist in the conservation field for over two decades, and transitioning into an educational doctorate with an emphasis on feminist, posthumanist, and care frameworks to address environmental and social justice concerns. Furthermore, I am a Brown Creole woman who was raised as a Muslim in Camissa, South Africa. The overarching question this dissertation seeks to address is; How can reparative care pedagogies reshape the hydrocommons for Black and Brown communities in post-apartheid South Africa? In order to respond to this question, I think diffractively with theory from feminism(s), posthumanism, research-creation and Slow scholarship - all of these are predicated on relational ontologies which embrace diverse ways of knowledge production in caring and meaning-making ways (Springgay & Truman, 2018; Stengers, 2011; Taylor et al, 2020). The research question I have posed is addressed through two key methods of enquiry namely strandlooping (beach walking) and hydro-rugging (stitching and mending). While there has been some literature on walking and mending methodologies from Northern contexts, I have opted to contextualise them within a South African framework with indigenous origins. By developing such methodologies in the local context, I aim to understand their application and relevance within South Africa's diverse cultural and environmental landscape. I have deliberately incorporated indigenous perspectives and practices in order to contribute to a more holistic and nuanced exploration of watery relations through iterative and collaborative events with participants. Chapter One provides an overview of my positionality and research practice by giving voice to those who have been marginalised, silenced and erased for three decades. The 30th anniversary for our first democratic elections was celebrated on the 27th April 2024 whilst I have been finalising my manuscript. The silence and erasure persist today, even though apartheid laws and regulations are no longer in effect. This lingering silence continues to permeate our lives and linger as a haunting presence. Consequently, strandlooping and hydro-rugging emerge as methods of enquiry that foster and provide avenues for care and healing. Chapter Two shares the stories of four Brown bodies and a tidal pool each of whom have a relationship with False Bay. The chapter shows how watery stories are shared through the process of hydro-rugging at the tidal pools. Chapter Three unravels the practice of strandlooping and develops propositions or watermarks to assist other researchers with this practice in their own contexts. Chapter Four articulates hydro-rugging as a method of enquiry and elucidates how the individual hydro-rugs are stitched alongside each other to create the Mother Hydro-rug. Chapter Five introduces three experiential research-creation events with fourth year students to meander and learn from them with regards to care for our hydrocommons. Drawing on relational ways of understanding and engaging with the world, this research culminates in several key implications for reparative care pedagogies in reshaping the hydrocommons. It underscores the importance of not only acknowledging but including diverse modes of knowledge and existence, particularly within Black and Brown communities marginalised by apartheid's racial and ethnic divisions. Additionally, it highlights the significance of challenging traditional educational paradigms entrenched in colonial and apartheid legacies. By prioritising embodied, experiential, and inclusive methodologies, the doctoral thesis advocates for a pedagogical shift toward relationality and process-oriented learning. This thesis prompts a reevaluation of extractive and exploitative educational practices, advocating instead for conviviality and the exploration of relational and embodied meanings and approaches. , Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Co-crystal formation of pharmaceutical and veterinary tranquilizer molecules
- Mngwengwe, Bongeka Naledi Precious
- Authors: Mngwengwe, Bongeka Naledi Precious
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464532 , vital:76519
- Description: Midazolam, a 1,4-benzodiazepine derivative is commonly used to treat anxiety, insomnia and may be used as a sedative in anaesthesia as it has calming, anti-convulsant and muscle relaxant properties. Midazolam has a rapid onset but a short duration of action resulting in fewer adverse effects. Midazolam also has the potential to form insoluble crystalline precipitates in pharmaceutical dosage forms such as syrups and solutions, which is a challenge in formulation and process development activities. The primary goal of this research was to prepare multicomponent crystals of midazolam free base, specifically targeting interactions with coformers structurally similar to methyl paraben. Key preparation techniques included neat grinding, liquid-assisted grinding, and slow evaporation. The resulting solid forms were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and powder X-Ray Diffraction (PXRD). In addition, Single-Crystal X-Ray Diffraction (SCXRD) was used to elucidate detailed structural information on the novel multicomponent crystals formed. Successful preparation of midazolam free base from the hydrochloride salt was confirmed through FTIR, DSC, and PXRD analysis. Different co-crystals and salts of midazolam with coformers such as salicylic acid (SA), benzoic acid (BA), 3-hydroxybenzoic acid (3-HBA) and p-aminobenzoic acid (PABA) were synthesized and characterized. The structure of the single crystal obtained from a veterinary tranquilizer solution was solved and found to be a salt that had formed between midazolam free base, midazolam HCl, and methyl paraben. This finding inspired further investigation of similar multicomponent crystals of midazolam and methyl paraben analogues. This study demonstrated the effectiveness of both mechanochemical and slow evaporation methods for the preparation of multicomponent crystals. PXRD and DSC provided insights into the stability and purity of the crystals that had formed and the differences in melting points and PXRD patterns were particularly important in this regard. Differences in FTIR spectra were used to distinguish between different solid forms and to confirm the successful formation of new solid forms. Extensive searches in the Cambridge Structural Database (CSD) confirmed that the multicomponent crystals of midazolam, such as MDZ‧SA, MDZ‧BA, MDZ‧3-HBA, and MDZ‧PABA, had not previously been reported, highlighting the novelty of these findings. The research successfully isolated and characterized several novel multicomponent crystals of midazolam, demonstrating the potential of mechanochemistry and solvent evaporation techniques in the development of pharmaceutical and veterinary medicinal applications. These findings contribute to the understanding of cocrystal formation and provide a foundation for future studies in which the stability and efficacy of midazolam-based formulations can be evaluated. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mngwengwe, Bongeka Naledi Precious
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464532 , vital:76519
- Description: Midazolam, a 1,4-benzodiazepine derivative is commonly used to treat anxiety, insomnia and may be used as a sedative in anaesthesia as it has calming, anti-convulsant and muscle relaxant properties. Midazolam has a rapid onset but a short duration of action resulting in fewer adverse effects. Midazolam also has the potential to form insoluble crystalline precipitates in pharmaceutical dosage forms such as syrups and solutions, which is a challenge in formulation and process development activities. The primary goal of this research was to prepare multicomponent crystals of midazolam free base, specifically targeting interactions with coformers structurally similar to methyl paraben. Key preparation techniques included neat grinding, liquid-assisted grinding, and slow evaporation. The resulting solid forms were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and powder X-Ray Diffraction (PXRD). In addition, Single-Crystal X-Ray Diffraction (SCXRD) was used to elucidate detailed structural information on the novel multicomponent crystals formed. Successful preparation of midazolam free base from the hydrochloride salt was confirmed through FTIR, DSC, and PXRD analysis. Different co-crystals and salts of midazolam with coformers such as salicylic acid (SA), benzoic acid (BA), 3-hydroxybenzoic acid (3-HBA) and p-aminobenzoic acid (PABA) were synthesized and characterized. The structure of the single crystal obtained from a veterinary tranquilizer solution was solved and found to be a salt that had formed between midazolam free base, midazolam HCl, and methyl paraben. This finding inspired further investigation of similar multicomponent crystals of midazolam and methyl paraben analogues. This study demonstrated the effectiveness of both mechanochemical and slow evaporation methods for the preparation of multicomponent crystals. PXRD and DSC provided insights into the stability and purity of the crystals that had formed and the differences in melting points and PXRD patterns were particularly important in this regard. Differences in FTIR spectra were used to distinguish between different solid forms and to confirm the successful formation of new solid forms. Extensive searches in the Cambridge Structural Database (CSD) confirmed that the multicomponent crystals of midazolam, such as MDZ‧SA, MDZ‧BA, MDZ‧3-HBA, and MDZ‧PABA, had not previously been reported, highlighting the novelty of these findings. The research successfully isolated and characterized several novel multicomponent crystals of midazolam, demonstrating the potential of mechanochemistry and solvent evaporation techniques in the development of pharmaceutical and veterinary medicinal applications. These findings contribute to the understanding of cocrystal formation and provide a foundation for future studies in which the stability and efficacy of midazolam-based formulations can be evaluated. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
- Full Text:
- Date Issued: 2024-10-11
Co-management and social equity at Silaka and Hluleka Nature Reserves, South Africa
- Authors: Mtshintsho, Anda
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464834 , vital:76549
- Description: Co-management of protected areas (PAs) is a desired conservation approach aimed at balancing ecological goals and livelihood needs. Central to co-management are issues related to power sharing, responsibilities and benefit sharing. However, there still remains a dominance of an ecological emphasis in PA management, with studies focusing more on ‘objective’ biodiversity indicators for measuring the effectiveness of protected areas. However, focusing only on ecological indicators addresses a narrow perspective of achieving ecological integrity and misses social dimensions that, in some cases, might be considered more important than technical considerations. Particularly, in contexts with a history of socio-physical displacement of Indigenous people and local communities (IPLC), the social dimensions of wellbeing are complexly embedded into the economic and ecological dimensions, such that ignoring these linkages might jeopardise the success of protected areas. Thus, the aim of this study was to examine the state of research and conceptual advances on social indicators of conservation success in co-managed PAs and stakeholder views and perceptions on socially just conservation in co-managed protected areas in Silaka and Hluleka Nature Reserves, South Africa. To achieve this, a scoping review, semi-structured interviews and futures workshops (using the three horizons framework) were conducted. Findings from the scoping review (chapter 2) revealed that much of the reported social monitoring indicators still rely on quantifiable metrics (i.e., economic benefits) and less on subjective and relational metrics (i.e., qualitative strength of social networks and perceptions). Unsurprisingly, many of the reviewed case studies revealed the use of participation as an indicator of evaluating co-management success. Further, the interviews and futures workshop results in chapter 3 showed that the non-accrual of key co-management expectations such as the employment of local people, benefit-sharing (material or otherwise), participation in decision-making and community development has led to heightened conflicts between the reserve management agency and local people. Consequently, the respondents did not value the co-management arrangements, citing unfulfilled promises. Broadly, the findings of this study emphasise the need for collective and collaborative efforts in developing indicators that are not only socially just but those that are context dependent and sensitive. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mtshintsho, Anda
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464834 , vital:76549
- Description: Co-management of protected areas (PAs) is a desired conservation approach aimed at balancing ecological goals and livelihood needs. Central to co-management are issues related to power sharing, responsibilities and benefit sharing. However, there still remains a dominance of an ecological emphasis in PA management, with studies focusing more on ‘objective’ biodiversity indicators for measuring the effectiveness of protected areas. However, focusing only on ecological indicators addresses a narrow perspective of achieving ecological integrity and misses social dimensions that, in some cases, might be considered more important than technical considerations. Particularly, in contexts with a history of socio-physical displacement of Indigenous people and local communities (IPLC), the social dimensions of wellbeing are complexly embedded into the economic and ecological dimensions, such that ignoring these linkages might jeopardise the success of protected areas. Thus, the aim of this study was to examine the state of research and conceptual advances on social indicators of conservation success in co-managed PAs and stakeholder views and perceptions on socially just conservation in co-managed protected areas in Silaka and Hluleka Nature Reserves, South Africa. To achieve this, a scoping review, semi-structured interviews and futures workshops (using the three horizons framework) were conducted. Findings from the scoping review (chapter 2) revealed that much of the reported social monitoring indicators still rely on quantifiable metrics (i.e., economic benefits) and less on subjective and relational metrics (i.e., qualitative strength of social networks and perceptions). Unsurprisingly, many of the reviewed case studies revealed the use of participation as an indicator of evaluating co-management success. Further, the interviews and futures workshop results in chapter 3 showed that the non-accrual of key co-management expectations such as the employment of local people, benefit-sharing (material or otherwise), participation in decision-making and community development has led to heightened conflicts between the reserve management agency and local people. Consequently, the respondents did not value the co-management arrangements, citing unfulfilled promises. Broadly, the findings of this study emphasise the need for collective and collaborative efforts in developing indicators that are not only socially just but those that are context dependent and sensitive. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Cocrystals, salts and eutectics of anti-tuberculosis medicines
- Authors: Matlapeng, Tsebang Alice
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464521 , vital:76518
- Description: Tuberculosis 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, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Matlapeng, Tsebang Alice
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464521 , vital:76518
- Description: Tuberculosis 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, 2024
- Full Text:
- Date Issued: 2024-10-11
Combined biological and chemical control of Fusarium associated with Eldana Saccharina walker in South African sugarcane production
- Authors: Cele, Tholakele Gladness
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466502 , vital:76736
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Cele, Tholakele Gladness
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466502 , vital:76736
- Description: Restricted access. Expected release in 2026. , Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Comparative analysis of YOLOV5 and YOLOV8 for automated fish detection and classification in underwater environments
- Authors: Kuhlane, Luxolo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464333 , vital:76502
- Description: The application of traditional manual techniques for fish detection and classification faces significant challenges, primarily stemming from their labour-intensive nature and limited scalability. Automating these kinds of processes through computer vision practices and machine learning techniques has emerged as a potential solution in recent years. With the development of and increase in ease of access to new technology in recent years, the use of a deep learning object detector known as YOLO (You Only Look Once) in the detection and classification of fish has steadily become notably popular. This thesis thus explores suitable YOLO architectures for detecting and classifying fish. The YOLOv5 and YOLOv8 models were evaluated explicitly for detecting and classifying fish in underwater environments. The selection of these models was based on a literature review highlighting their success in similar applications but remains largely understudied in underwater environments. Therefore, the effectiveness of these models was evaluated through comprehensive experimentation on collected and publicly available underwater fish datasets. In collaboration with the South African Institute of Biodiversity (SAIAB), five datasets were collected and manually annotated for labels for supervised machine learning. Moreover, two publicly available datasets were sourced for comparison to the literature. Furthermore, after determining that the smallest YOLO architectures are better suited to these imbalanced datasets, hyperparameter tuning tailored the models to the characteristics of the various underwater environments used in the research. The popular DeepFish dataset was evaluated to establish a baseline and feasibility of these models in the understudied domain. The results demonstrated high detection accuracy for both YOLOv5 and YOLOv8. However, YOLOv8 outperformed YOLOv5, achieving 97.43% accuracy compared to 94.53%. After experiments on seven datasets, trends revealed YOLOv8’s enhanced generalisation accuracy due to architectural improvements, particularly in detecting smaller fish. Overall, YOLOv8 demonstrated that it is the better fish detection and classification model on diverse data. , Thesis (MSc) -- Faculty of Science, Computer Science, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Kuhlane, Luxolo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464333 , vital:76502
- Description: The application of traditional manual techniques for fish detection and classification faces significant challenges, primarily stemming from their labour-intensive nature and limited scalability. Automating these kinds of processes through computer vision practices and machine learning techniques has emerged as a potential solution in recent years. With the development of and increase in ease of access to new technology in recent years, the use of a deep learning object detector known as YOLO (You Only Look Once) in the detection and classification of fish has steadily become notably popular. This thesis thus explores suitable YOLO architectures for detecting and classifying fish. The YOLOv5 and YOLOv8 models were evaluated explicitly for detecting and classifying fish in underwater environments. The selection of these models was based on a literature review highlighting their success in similar applications but remains largely understudied in underwater environments. Therefore, the effectiveness of these models was evaluated through comprehensive experimentation on collected and publicly available underwater fish datasets. In collaboration with the South African Institute of Biodiversity (SAIAB), five datasets were collected and manually annotated for labels for supervised machine learning. Moreover, two publicly available datasets were sourced for comparison to the literature. Furthermore, after determining that the smallest YOLO architectures are better suited to these imbalanced datasets, hyperparameter tuning tailored the models to the characteristics of the various underwater environments used in the research. The popular DeepFish dataset was evaluated to establish a baseline and feasibility of these models in the understudied domain. The results demonstrated high detection accuracy for both YOLOv5 and YOLOv8. However, YOLOv8 outperformed YOLOv5, achieving 97.43% accuracy compared to 94.53%. After experiments on seven datasets, trends revealed YOLOv8’s enhanced generalisation accuracy due to architectural improvements, particularly in detecting smaller fish. Overall, YOLOv8 demonstrated that it is the better fish detection and classification model on diverse data. , Thesis (MSc) -- Faculty of Science, Computer Science, 2024
- Full Text:
- Date Issued: 2024-10-11
Composition portfolio
- Authors: Musambasi, Richie Andile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466094 , vital:76684
- Description: Indigenous Zimbabwean music is complex in its make up and reveals spiritual beliefs, modes of expression, communication patterns, and forms of entertainment. The goal of this composition portfolio is to create pieces that are imbued with the spirit of indigenous Zimbabwean music making as passed on from father to son. The pieces composed include thorough-composed (pre-determined) solo and ensemble frameworks using mostly marimbas based largely on Shona scales and tuning, but also adding mbira, hosho and djembe. All of this is presented within complex structural manipulations that include African and some Western elements of formal music structure. The compositions feature two interlocking parts, known as kushaura and kutsinhira (call and respond), which are traditionally played in a simultaneous manner by two or more musicians. In this portfolio, these voices are spread across a range of players where the interplay between the parts produces complex polyphonic and polyrhythmic musical relationships. The compositions explore modal changes which add excitement, variety and an extra layer of complexity to the pieces. The final artefact is presented as a multimedia submission recorded as a documentary in real time, which is a representation of the embodied making of the music, central to this project. As music was passed down through folk tales, religious gatherings, rock paintings and sources of art, the narration is the key element in expressing that knowledge dissemination is not only text bound, but also embodied and orally shared. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Musambasi, Richie Andile
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466094 , vital:76684
- Description: Indigenous Zimbabwean music is complex in its make up and reveals spiritual beliefs, modes of expression, communication patterns, and forms of entertainment. The goal of this composition portfolio is to create pieces that are imbued with the spirit of indigenous Zimbabwean music making as passed on from father to son. The pieces composed include thorough-composed (pre-determined) solo and ensemble frameworks using mostly marimbas based largely on Shona scales and tuning, but also adding mbira, hosho and djembe. All of this is presented within complex structural manipulations that include African and some Western elements of formal music structure. The compositions feature two interlocking parts, known as kushaura and kutsinhira (call and respond), which are traditionally played in a simultaneous manner by two or more musicians. In this portfolio, these voices are spread across a range of players where the interplay between the parts produces complex polyphonic and polyrhythmic musical relationships. The compositions explore modal changes which add excitement, variety and an extra layer of complexity to the pieces. The final artefact is presented as a multimedia submission recorded as a documentary in real time, which is a representation of the embodied making of the music, central to this project. As music was passed down through folk tales, religious gatherings, rock paintings and sources of art, the narration is the key element in expressing that knowledge dissemination is not only text bound, but also embodied and orally shared. , Thesis (MA) -- Faculty of Humanities, Music and Musicology, 2024
- Full Text:
- Date Issued: 2024-10-11
Computational search for nature-derived dual-action inhibitors of HIV-1 reverse transcriptase and integrase: a potential strategy to mitigate drug resistance progression
- Authors: Mwiinga, Luyando
- Date: 2024-10-11
- Subjects: HIV (Viruses) , Reverse transcriptase , Antiretroviral agents , RDKit , Drug resistance , Docking
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463930 , vital:76458
- Description: Human immunodeficiency virus Type 1 (HIV-1) is a devastating viral infection affecting millions worldwide and presents significant challenges in treatment and management. In 2022, approximately 39 million people were living with HIV with Sub-Saharan Africa having two thirds of these infections. Devastatingly, there were approximately 300 000 HIV/AIDS related deaths in Sub-Saharan Africa alone in 2022 alone. Antiretroviral therapy (ART) which is fundamental for HIV treatment, comprises of a combination of drugs such as nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs). However, although 28.7 million people out of the estimated 38.4 million people living with HIV in 2021 were receiving ART, the emergence of drug-resistant strains further complicates treatment efforts, highlighting the need for novel therapeutic approaches. This study aimed to address the challenges raised by drug resistance and significant side effects by identifying potential dual inhibitors against HIV-1 Reverse Transcriptase (RT) and Integrase (IN) using in silico techniques. RT RNase H and IN were chosen as targets for their shared dependency on Mg2+ ions within their active sites, which are crucial for catalytic activity. The selection of dual inhibitors was motivated by the fact that the virus would need to replicate at two points simultaneously to develop resistance, making it less likely. The objectives of this study included the creation of a natural derivative compound library using RDKit with the aid of SciFinder, utilizing (-)-epigallocatechin-3-O-gallate (EGCG), because of its dual inhibitory effects against RT and IN, as indicated by a study conducted by Sanna et al. 2019. The natural derivatives were chosen to take advantage of their chemical diversity and to explore potential novel therapeutic options for combating HIV drug resistance. The compound library created comprised of 125 203 compounds. Then docking studies were conducted to assess proteinligand binding. After the correlation of the RT and IN docking studies, 288 compounds were filtered to have potential dual inhibitory activity. Then quantitative estimation of druggability (QED) analysis identified three compounds with superior properties compared to EGCG and FDAapproved drug raltegravir (RAL). Molecular docking simulations revealed interactions between the inhibitors and the key active site residues of RT and IN, along with the chelation of at least one 3 Mg2+, suggesting the potential for enzymatic disruption. Furthermore, molecular dynamic (MD) simulations were then conducted to assess protein-ligand system behavior, through RMSD and RMSF analysis. The RMSD analysis uncovered instability in the IN-Sci30703 complex, leading to its exclusion as a potential dual action inhibitor. RMSF analysis for IN showed that all the inhibitors had the ability to limit the flexibility of the catalytic loop which is essential for catalytic activity. Therefore, further in vitro studies are required to evaluate the effectiveness of the remaining two EGCG derivatives (Sci33211 and Sci48919) in inhibiting RT and IN through the chelation of at least one Mg2+ ion to determine if they have superior dual inhibitory effects compared to EGCG. This study adds to the ongoing efforts to develop effective strategies against HIV-1 drug resistance and emphasizes the importance of continued research in this field. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Mwiinga, Luyando
- Date: 2024-10-11
- Subjects: HIV (Viruses) , Reverse transcriptase , Antiretroviral agents , RDKit , Drug resistance , Docking
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463930 , vital:76458
- Description: Human immunodeficiency virus Type 1 (HIV-1) is a devastating viral infection affecting millions worldwide and presents significant challenges in treatment and management. In 2022, approximately 39 million people were living with HIV with Sub-Saharan Africa having two thirds of these infections. Devastatingly, there were approximately 300 000 HIV/AIDS related deaths in Sub-Saharan Africa alone in 2022 alone. Antiretroviral therapy (ART) which is fundamental for HIV treatment, comprises of a combination of drugs such as nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTs), protease inhibitors (PIs) and integrase strand transfer inhibitors (INSTIs). However, although 28.7 million people out of the estimated 38.4 million people living with HIV in 2021 were receiving ART, the emergence of drug-resistant strains further complicates treatment efforts, highlighting the need for novel therapeutic approaches. This study aimed to address the challenges raised by drug resistance and significant side effects by identifying potential dual inhibitors against HIV-1 Reverse Transcriptase (RT) and Integrase (IN) using in silico techniques. RT RNase H and IN were chosen as targets for their shared dependency on Mg2+ ions within their active sites, which are crucial for catalytic activity. The selection of dual inhibitors was motivated by the fact that the virus would need to replicate at two points simultaneously to develop resistance, making it less likely. The objectives of this study included the creation of a natural derivative compound library using RDKit with the aid of SciFinder, utilizing (-)-epigallocatechin-3-O-gallate (EGCG), because of its dual inhibitory effects against RT and IN, as indicated by a study conducted by Sanna et al. 2019. The natural derivatives were chosen to take advantage of their chemical diversity and to explore potential novel therapeutic options for combating HIV drug resistance. The compound library created comprised of 125 203 compounds. Then docking studies were conducted to assess proteinligand binding. After the correlation of the RT and IN docking studies, 288 compounds were filtered to have potential dual inhibitory activity. Then quantitative estimation of druggability (QED) analysis identified three compounds with superior properties compared to EGCG and FDAapproved drug raltegravir (RAL). Molecular docking simulations revealed interactions between the inhibitors and the key active site residues of RT and IN, along with the chelation of at least one 3 Mg2+, suggesting the potential for enzymatic disruption. Furthermore, molecular dynamic (MD) simulations were then conducted to assess protein-ligand system behavior, through RMSD and RMSF analysis. The RMSD analysis uncovered instability in the IN-Sci30703 complex, leading to its exclusion as a potential dual action inhibitor. RMSF analysis for IN showed that all the inhibitors had the ability to limit the flexibility of the catalytic loop which is essential for catalytic activity. Therefore, further in vitro studies are required to evaluate the effectiveness of the remaining two EGCG derivatives (Sci33211 and Sci48919) in inhibiting RT and IN through the chelation of at least one Mg2+ ion to determine if they have superior dual inhibitory effects compared to EGCG. This study adds to the ongoing efforts to develop effective strategies against HIV-1 drug resistance and emphasizes the importance of continued research in this field. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
- Full Text:
- Date Issued: 2024-10-11
Connecting culture and science: Utilising Oshikundu and Ombidi in biology lessons on diffusion and osmosis
- Shilomboleni, Helena Ilena Ndilimeke
- Authors: Shilomboleni, Helena Ilena Ndilimeke
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463636 , vital:76427
- Description: Various science curricula including that of Namibia recommend that teaching and learning should start with the knowledge and experiences of learners from their homes and communities. These experiences are the learners’ Indigenous Knowledge (IK) which should be integrated to make science accessible and relevant to learners from diverse sociocultural backgrounds. This suggests that science teachers are encouraged to integrate IK into their teaching to help learners grasp abstract concepts and construct their own understanding of phenomena. However, much literature has revealed that many teachers find it difficult to integrate IK into their science teaching. Some scholars further argue that teachers lack the pedagogical content knowledge to effectively integrate IK. I assume this could be because the science curriculum is not explicit on how IK should be integrated into science teaching. It is against this backdrop that in this study I mobilised the Indigenous technologies of making oshikundu and preserving ombidi to support Grade 10 Biology learners in talking and making sense of diffusion and osmosis. This study was underpinned by the interpretivist and Indigenous research paradigms. Within the Indigenous research paradigm, I focused on Ubuntu as a perspective. A qualitative case study was employed and conducted at a certain school in the northern part of Namibia, in the Ohangwena region. I worked with a group of 35 Grade 10 learners, two Indigenous Knowledge Custodians (KCs) who are the custodians of cultural heritage and one Biology teacher (critical friend) as participants in this study. Qualitative data were collected using a focus group interview (sharing circle), group activity, participatory observation, and learners’ journal reflections. Vygotsky’s sociocultural theory together with Ogunniyi’s Contiguity Argumentative Theory were used as lenses to analyse data. The findings of the study revealed that during the IKCs’ practical demonstrations learners were able to identify science concepts embedded in the cultural practices of making oshikundu and preserving ombidi. The findings further revealed that the practical demonstrations enhanced active participation and interactions among learners. I thus recommend that teachers should tap into IKCs’ cultural heritage by inviting them into their classrooms to make science relevant, accessible and meaningful to learners. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Shilomboleni, Helena Ilena Ndilimeke
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463636 , vital:76427
- Description: Various science curricula including that of Namibia recommend that teaching and learning should start with the knowledge and experiences of learners from their homes and communities. These experiences are the learners’ Indigenous Knowledge (IK) which should be integrated to make science accessible and relevant to learners from diverse sociocultural backgrounds. This suggests that science teachers are encouraged to integrate IK into their teaching to help learners grasp abstract concepts and construct their own understanding of phenomena. However, much literature has revealed that many teachers find it difficult to integrate IK into their science teaching. Some scholars further argue that teachers lack the pedagogical content knowledge to effectively integrate IK. I assume this could be because the science curriculum is not explicit on how IK should be integrated into science teaching. It is against this backdrop that in this study I mobilised the Indigenous technologies of making oshikundu and preserving ombidi to support Grade 10 Biology learners in talking and making sense of diffusion and osmosis. This study was underpinned by the interpretivist and Indigenous research paradigms. Within the Indigenous research paradigm, I focused on Ubuntu as a perspective. A qualitative case study was employed and conducted at a certain school in the northern part of Namibia, in the Ohangwena region. I worked with a group of 35 Grade 10 learners, two Indigenous Knowledge Custodians (KCs) who are the custodians of cultural heritage and one Biology teacher (critical friend) as participants in this study. Qualitative data were collected using a focus group interview (sharing circle), group activity, participatory observation, and learners’ journal reflections. Vygotsky’s sociocultural theory together with Ogunniyi’s Contiguity Argumentative Theory were used as lenses to analyse data. The findings of the study revealed that during the IKCs’ practical demonstrations learners were able to identify science concepts embedded in the cultural practices of making oshikundu and preserving ombidi. The findings further revealed that the practical demonstrations enhanced active participation and interactions among learners. I thus recommend that teachers should tap into IKCs’ cultural heritage by inviting them into their classrooms to make science relevant, accessible and meaningful to learners. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
- Full Text:
- Date Issued: 2024-10-11
Context-related drivers, occurrence and human exposure to antibiotic resistant Campylobacter in selected river systems in the Eastern Cape, South Africa
- Authors: Chibwe, Mary
- Date: 2024-10-11
- Subjects: Antibiotic resistance , Campylobacter , Health risk assessment , Drug resistance , Public health South Africa Eastern Cape , Polymerase chain reaction
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466644 , vital:76763 , DOI https://doi.org/10.21504/10962/466644
- Description: The increasing prevalence of antibiotic-resistant Campylobacter species in river systems is a growing public health concern globally. This challenge presents the need to understand the drivers influencing the occurrence of these antibiotic-resistant strains to inform effective mitigation strategies. Identifying local anthropogenic pressures/activities will enable tailored intervention and ensure that management efforts are targeted and effective in mitigating actual risks faced by local water resources. In particular, the occurrence of antibiotic-resistant Campylobacter in river systems causes concerns regarding potential human exposure. Campylobacter species are regularly implicated in both animal and human diarrhoea, and have gained recognition as one of the main causes of waterborne diseases. This study investigated context-related drivers to the presence of antibiotic-resistant Campylobacter, its occurrence, and the risk of human exposure in the Bloukrans and Swartkops rivers in the Eastern Cape, South Africa. The study utilised a questionnaire survey and focus group discussions to identify context-related sources and drivers of antibiotic-resistant bacteria and genes in the Bloukrans and Swartkops rivers. Additionally, physico-chemical analysis of water samples was done, and polymerase chain reaction (PCR) was employed to investigate occurrences of Campylobacter in both rivers, as well as the presence of virulent and antibiotic-resistant genes. Two control sites, one for each river, and a total of nine other sampling sites were selected for this study, four along the Bloukrans River and five along the Swartkops River. Water samples were collected from all eleven sites over a period of one year, covering all the seasons (winter, spring, summer and autumn). Exposure assessment was investigated by conducting propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) to quantify the concentration of viable Campylobacter and its antibiotic-resistance genes (ARGs) in the river water. The calculated concentration of viable Campylobacter and ARGs was then used to estimate human exposure dose of antibiotic-resistant Campylobacter via unintentional ingestion during swimming in the Bloukrans or Swartkops rivers. The questionnaire surveys and focus group discussions identified the factors of socio-demographic characteristics of the study catchments, lack of knowledge regarding antibiotic resistance, inappropriate antibiotic and disposal practices as well as anthropogenic activities (improper solid waste management, discharge of poorly treated wastewater, poor animal husbandry practices, urban run-off and storm water, industrial effluent and agricultural run-off) as context-related sources and drivers contributing to the emergence and of continuing occurrence antibiotic-resistant bacteria and genes in the Bloukrans and Swartkops rivers. The results obtained in this study suggest that the physiochemical properties of the water in the Bloukrans and Swartkops rivers are conducive for Campylobacter survival. The prevalence of Campylobacter was high at sites that recorded high turbidity, low dissolved oxygen and high conductivity. This study also highlighted the widespread and continual presence of Campylobacter spp. in the Bloukrans and Swartkops rivers, which are potentially antibiotic-resistant. The prevalence of Campylobacter was 60% virulence genes were detected at 15% (cadF), 10% (htrB), 10% (clpP), 5% (ciaB) and 5% (ctdC) for water samples from the Bloukrans River. Campylobacter was detected in 58% of water samples from the Swartkops River, while cadF, htrB, ciaB, clpP and ctdB were detected at 24%, 0%, 9.5%, 14.8% and 4.8%, respectively. Of the Campylobacter-positive water samples, the virulence genes cmeA, cmeB and cmeC were detected in 20%, 65% and 10% of the water samples from Bloukrans River, respectively. Similarly, the genes cmeA, cmeB and cmeC were detected at 14.3%, 52% and 9.5%, respectively, for the Swartkops River. Tetracycline resistance genes (tetO) were detected in 70% and 76% of the water samples collected from the Bloukrans and Swartkops rivers, respectively. It was also observed that the sampling site had a significant effect on the detection of Campylobacter for both rivers (p < 0.05). The prevalence of Campylobacter was higher for sites impacted by anthropogenic activities. The results show that sampling season had no significant effect on the occurrence of Campylobacter for both rivers. The analysis through PMA-qPCR revealed that the mean concentrations of the Campylobacter 16S rRNA gene from viable cells ranged from 2.1 × 104 to 1.75 × 105 copies/ml for the Bloukrans River, and from 0 (no detection) to 1.11 × 104 copies/ml (viable concentration) for the Swartkops River. The concentration of tetO from viable cells ranged from 4.75 × 101 to 2.71 × 103 copies/ml and 115.96 to 325.12 copies/ml, for the Bloukrans and Swartkops Rivers, respectively. Similarly, the concentration of cmeB genes from viable cells ranged from 7.8 × 101 to 2.76 × 104 copies/ml for the Bloukrans River and from 1.71 × 101 to 7.39 × 103 copies/ml for the Swartkops River. We utilized the calculated concentrations of viable Campylobacter 16S rRNA genes and ARGs to estimate the human intake burden of viable Campylobacter 16S rRNA copies per one-hour of swimming to range from 9.9 × 101 – 3.7 × 106 copies/h across the two rivers. The human intake burden of Campylobacter ARGs ranged from 3.6 × 102 – 5.8 × 105 copies/h for cmeB, and 9.98 × 102 – 5.7 × 104 copies/h for tetO. This study highlighted the intricate interplay of socio-demographic characteristics in the study catchments, such as insufficient awareness of antibiotic resistance, inappropriate antibiotic disposal practices and anthropogenic activities, which all contribute to the prevalence of antibiotic-resistant Campylobacter in the Bloukrans and Swartkops rivers, emphasizing the need for targeted interventions to address these specific influences. There is a potential risk of Campylobacter infections associated with human exposure to the rivers. This work contributes towards the body of knowledge in closing the current research gap on possible human exposure to antibiotic-resistant Campylobacter, and in general, exposure to ARBs through freshwater sources. The findings have practical implications for designing targeted interventions to mitigate these risks, to enhance the overall environmental and public health management in the region. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Chibwe, Mary
- Date: 2024-10-11
- Subjects: Antibiotic resistance , Campylobacter , Health risk assessment , Drug resistance , Public health South Africa Eastern Cape , Polymerase chain reaction
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/466644 , vital:76763 , DOI https://doi.org/10.21504/10962/466644
- Description: The increasing prevalence of antibiotic-resistant Campylobacter species in river systems is a growing public health concern globally. This challenge presents the need to understand the drivers influencing the occurrence of these antibiotic-resistant strains to inform effective mitigation strategies. Identifying local anthropogenic pressures/activities will enable tailored intervention and ensure that management efforts are targeted and effective in mitigating actual risks faced by local water resources. In particular, the occurrence of antibiotic-resistant Campylobacter in river systems causes concerns regarding potential human exposure. Campylobacter species are regularly implicated in both animal and human diarrhoea, and have gained recognition as one of the main causes of waterborne diseases. This study investigated context-related drivers to the presence of antibiotic-resistant Campylobacter, its occurrence, and the risk of human exposure in the Bloukrans and Swartkops rivers in the Eastern Cape, South Africa. The study utilised a questionnaire survey and focus group discussions to identify context-related sources and drivers of antibiotic-resistant bacteria and genes in the Bloukrans and Swartkops rivers. Additionally, physico-chemical analysis of water samples was done, and polymerase chain reaction (PCR) was employed to investigate occurrences of Campylobacter in both rivers, as well as the presence of virulent and antibiotic-resistant genes. Two control sites, one for each river, and a total of nine other sampling sites were selected for this study, four along the Bloukrans River and five along the Swartkops River. Water samples were collected from all eleven sites over a period of one year, covering all the seasons (winter, spring, summer and autumn). Exposure assessment was investigated by conducting propidium monoazide-quantitative polymerase chain reaction (PMA-qPCR) to quantify the concentration of viable Campylobacter and its antibiotic-resistance genes (ARGs) in the river water. The calculated concentration of viable Campylobacter and ARGs was then used to estimate human exposure dose of antibiotic-resistant Campylobacter via unintentional ingestion during swimming in the Bloukrans or Swartkops rivers. The questionnaire surveys and focus group discussions identified the factors of socio-demographic characteristics of the study catchments, lack of knowledge regarding antibiotic resistance, inappropriate antibiotic and disposal practices as well as anthropogenic activities (improper solid waste management, discharge of poorly treated wastewater, poor animal husbandry practices, urban run-off and storm water, industrial effluent and agricultural run-off) as context-related sources and drivers contributing to the emergence and of continuing occurrence antibiotic-resistant bacteria and genes in the Bloukrans and Swartkops rivers. The results obtained in this study suggest that the physiochemical properties of the water in the Bloukrans and Swartkops rivers are conducive for Campylobacter survival. The prevalence of Campylobacter was high at sites that recorded high turbidity, low dissolved oxygen and high conductivity. This study also highlighted the widespread and continual presence of Campylobacter spp. in the Bloukrans and Swartkops rivers, which are potentially antibiotic-resistant. The prevalence of Campylobacter was 60% virulence genes were detected at 15% (cadF), 10% (htrB), 10% (clpP), 5% (ciaB) and 5% (ctdC) for water samples from the Bloukrans River. Campylobacter was detected in 58% of water samples from the Swartkops River, while cadF, htrB, ciaB, clpP and ctdB were detected at 24%, 0%, 9.5%, 14.8% and 4.8%, respectively. Of the Campylobacter-positive water samples, the virulence genes cmeA, cmeB and cmeC were detected in 20%, 65% and 10% of the water samples from Bloukrans River, respectively. Similarly, the genes cmeA, cmeB and cmeC were detected at 14.3%, 52% and 9.5%, respectively, for the Swartkops River. Tetracycline resistance genes (tetO) were detected in 70% and 76% of the water samples collected from the Bloukrans and Swartkops rivers, respectively. It was also observed that the sampling site had a significant effect on the detection of Campylobacter for both rivers (p < 0.05). The prevalence of Campylobacter was higher for sites impacted by anthropogenic activities. The results show that sampling season had no significant effect on the occurrence of Campylobacter for both rivers. The analysis through PMA-qPCR revealed that the mean concentrations of the Campylobacter 16S rRNA gene from viable cells ranged from 2.1 × 104 to 1.75 × 105 copies/ml for the Bloukrans River, and from 0 (no detection) to 1.11 × 104 copies/ml (viable concentration) for the Swartkops River. The concentration of tetO from viable cells ranged from 4.75 × 101 to 2.71 × 103 copies/ml and 115.96 to 325.12 copies/ml, for the Bloukrans and Swartkops Rivers, respectively. Similarly, the concentration of cmeB genes from viable cells ranged from 7.8 × 101 to 2.76 × 104 copies/ml for the Bloukrans River and from 1.71 × 101 to 7.39 × 103 copies/ml for the Swartkops River. We utilized the calculated concentrations of viable Campylobacter 16S rRNA genes and ARGs to estimate the human intake burden of viable Campylobacter 16S rRNA copies per one-hour of swimming to range from 9.9 × 101 – 3.7 × 106 copies/h across the two rivers. The human intake burden of Campylobacter ARGs ranged from 3.6 × 102 – 5.8 × 105 copies/h for cmeB, and 9.98 × 102 – 5.7 × 104 copies/h for tetO. This study highlighted the intricate interplay of socio-demographic characteristics in the study catchments, such as insufficient awareness of antibiotic resistance, inappropriate antibiotic disposal practices and anthropogenic activities, which all contribute to the prevalence of antibiotic-resistant Campylobacter in the Bloukrans and Swartkops rivers, emphasizing the need for targeted interventions to address these specific influences. There is a potential risk of Campylobacter infections associated with human exposure to the rivers. This work contributes towards the body of knowledge in closing the current research gap on possible human exposure to antibiotic-resistant Campylobacter, and in general, exposure to ARBs through freshwater sources. The findings have practical implications for designing targeted interventions to mitigate these risks, to enhance the overall environmental and public health management in the region. , Thesis (PhD) -- Faculty of Science, Institute for Water Research, 2024
- Full Text:
- Date Issued: 2024-10-11
Decolonizing the curriculum: a case study of the Humanities Faculty at Rhodes University
- Authors: Machiha, Nigel
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466005 , vital:76676
- Description: This thesis explores students’ experiences in the Faculty of Humanities at Rhodes University, specifically focusing on their perspectives on decolonization. The thesis has two central aims: first, to investigate the students’ general understanding of decolonizing the curriculum and second, to examine their experiences within the Humanities Faculty and their perception of how decolonized the faculty is. Through in-depth interviews with students in the faculty, the study aimed to answer questions regarding students’ thoughts on the decolonization of university curricula and their experiences within the Faculty of Humanities at Rhodes University. The findings reveal diverse student views on decolonization, with definitions of decolonization provided by students touching on topics such as the Africanization or Indigenization of the curriculum, systemic transformation, the importance of unlearning colonial ideologies and the relationship between language and decolonization. The students’ perceptions of the level of decolonization they witness in the faculty are categorized along three lines: the views of those who believe the departments they interact with are decolonized, the views of those who think efforts are being made but more progress is needed, and those who see no evidence of decolonization. The thesis highlights that while some students believe that positive steps towards decolonization are being taken, others express scepticism and call for a more diverse representation of scholars and scholarship and a departure from traditional Eurocentric approaches. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Machiha, Nigel
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/466005 , vital:76676
- Description: This thesis explores students’ experiences in the Faculty of Humanities at Rhodes University, specifically focusing on their perspectives on decolonization. The thesis has two central aims: first, to investigate the students’ general understanding of decolonizing the curriculum and second, to examine their experiences within the Humanities Faculty and their perception of how decolonized the faculty is. Through in-depth interviews with students in the faculty, the study aimed to answer questions regarding students’ thoughts on the decolonization of university curricula and their experiences within the Faculty of Humanities at Rhodes University. The findings reveal diverse student views on decolonization, with definitions of decolonization provided by students touching on topics such as the Africanization or Indigenization of the curriculum, systemic transformation, the importance of unlearning colonial ideologies and the relationship between language and decolonization. The students’ perceptions of the level of decolonization they witness in the faculty are categorized along three lines: the views of those who believe the departments they interact with are decolonized, the views of those who think efforts are being made but more progress is needed, and those who see no evidence of decolonization. The thesis highlights that while some students believe that positive steps towards decolonization are being taken, others express scepticism and call for a more diverse representation of scholars and scholarship and a departure from traditional Eurocentric approaches. , Thesis (MA) -- Faculty of Humanities, Political and International Studies, 2024
- Full Text:
- Date Issued: 2024-10-11
Design and fabrication of millifluidic devices for maintenance of tissue cultures under perfusion
- Buthelezi, Khanyisile Thando Fatima
- Authors: Buthelezi, Khanyisile Thando Fatima
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464358 , vital:76504
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11
- Authors: Buthelezi, Khanyisile Thando Fatima
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464358 , vital:76504
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2024
- Full Text:
- Date Issued: 2024-10-11