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Microplastics as potential vectors for selected organic chemical pollutants in river ecosystems
No full textMicroplastics (MPs) as pollutants in river ecosystems have received considerable research attention in recent years. However, in Africa, research on MPs is sparse, and more needs to be done. Empirical evidence suggests that MP can act as vectors of organic chemical pollutants due to their diverse functional groups and other physical-chemical properties, such as their small sizes, crystal structure and porosity. MPs acting as vectors of chemical pollutants, adds to the complexity of understanding the risk posed to both the ecosystem and human health. Regarding the so-called vector effect, the role of seasonality, land use type, adsorption kinetics, and MP properties has yet to receive the necessary research in the literature, especially concerning pharmaceutical active compounds and other organic pollutants in river systems. This is particularly true for Africa, including South Africa. This study, therefore, aimed to fill these existing research gaps. Overall, the study aimed to investigate the potential of selected microplastic polymers of a particular size range as vectors of organic pollutants in urban rivers within the Eastern Cape of South Africa. To achieve this aim, the study explored the influence of spatial-temporal variability, MPs particle sizes, and various physicochemical variables on the adsorption of antibiotics: Sulfamethoxazole, ciprofloxacin, and endocrine disruptors: 17β-Estradiol, 4-(2, 6-dimethyl-2-heptyl) phenol. The adsorption kinetics mechanism was also investigated and established. Polyethylene Terephthalate (PET) and polypropylene (PP) MPs were seasonally deployed once in the summer and autumn seasons, i.e. 20th January 2022 in Bloukrans River and 21st January 2022 in Swartkops River for the summer season and 7th April 2022 in Bloukrans River and 8th April 2022 in Swartkops River for the autumn season. Deployed MPs were of two size ranges, type 1 (2 mm 0.99), indicating that chemisorption mechanisms may be the rate-limiting step. Data did not fit the intraparticle diffusion model. Both film diffusion and intraparticle diffusion possibly influenced the rate-limiting adsorption step simultaneously. Regarding the relationship between adsorption and water physico-chemical variables, of special interest a positive correlation between total alkalinity, electrical conductivity, total hardness, and total suspended salts (TDS) and the concentration of the adsorbed chemicals was observed. While the relationship between adsorption and dissolved oxygen was negative. The physicochemical variables with a positive relationship with adsorption are indicative of pollution. Therefore, the result suggests that increasing pollution tends to favour higher adsorption. The results in this study highlight the insights on i) the influence of land use on adsorption, ii) the role of exposure duration on adsorption, iii) the influence of seasonality and MP sizes on adsorption iv) relationship between water physicochemical parameters and adsorption as well as v) establishing adsorption kinetic mechanism. These findings are critical to better understanding the so-called vector effects of MPs and the management associated with MPs in river systems and form essential data sets needed in developing effective pollution mitigation strategies that are region-specific.Thesis (PhD) -- Faculty of Science, Institute for Water Research, 202
Navigating change: a critical analysis of social media’s role in shaping gender activists’ perspectives
Get PDFThis research explores the unique challenges and opportunities that social media offers gender activists fighting for equality and social justice. It examines the negative and positive elements of social media, highlighting the ways it can be adopted to build communities, amplify voices, and advance social change in unique ways, but also the ways in which it can adversely contribute to existing power imbalances and inequalities. This research does not concentrate on any specific gender-based movement, but rather aims to understand how gender activists in South Africa have embraced social media in their local activism. The study followed a qualitative approach and collected the data through in-depth semi-structured interviews. It also followed a thematic framework in its analysis of the data collected from the interviews. The study found that, while online gender activism in South Africa faces challenges such as harassment and the digital gender divide, there is still progress in terms of community building and political engagement on social media. The findings suggest that, in spite of the challenges, social media can still be an important tool for advancing gender-based social justice in South Africa. This research made use of Counter-publics and Cyberfeminism as guiding theoretical frameworks. The theory of Counter-publics provides a valuable way of understanding how virtual groups emerge and challenge dominant societal norms and values. Cyberfeminism provides insight into how women have challenged contemporary inequalities through the adoption of technologies such as social media. As sub-components to Cyber-feminism, Intersectionality and Standpoint perspectives were used to understand how activists’ diverse identities and social positions influence their individual forms of activism.Thesis (MSocSci) -- Faculty of Humanities, Sociology, 202
KalCal: a novel calibration framework for radio interferometry using the Kalman Filter and Smoother
Get PDFCalibration in radio interferometry is essential for correcting measurement errors. Traditional methods employ maximum likelihood techniques and non-linear least squares solvers but face challenges due to the data volumes and increased noise sensitivity of contemporary instruments such as MeerKAT. A common approach for mitigating these issues is using “solution intervals”, which helps manage the data volume and reduces overfitting. However, inappropriate interval sizes can degrade calibration quality, and determining optimal sizes is challenging, often relying on brute-force methods. This study introduces Kalman Filtering and Smoothing in Calibration (KalCal), a new framework for calibration that combines the Kalman Filter, Kalman Smoother, and the energy function: the negative logarithm of the Bayesian evidence. KalCal offers Bayesian-optimal solutions as probability densities and models calibration effects with lower computational requirements than iterative approaches. Unlike traditional methods, which require all the data for a particular solution to be in memory simultaneously, KalCal’s recursive computations only need a single pass through the data with appropriate prior information. The energy function provides the means for KalCal to determine this prior information. Theoretical contributions include additions to complex optimisation literature and the “Kalman-Woodbury Identity” that reformulates the traditional Kalman Filter. A Python implementation of the KalCal framework was benchmarked against solution intervals as implemented in the QuartiCal package. Simulations show KalCal matching solution intervals in high Signal-to-Noise Ratio (SNR) scenarios and surpassing them in low SNR conditions. Moreover, the energy function produced minima that coincide with KalCal’s Mean Square Error (MSE) on the true gain signal. This result is significant as the MSE is unavailable in real applications. Further research is needed to assess the computational feasibility and intricacies of KalCal.Thesis (MSc) -- Faculty of Science, Physics and Electronics, 202
A social realist account of the way smallholder farmers exercised their agency in the adoption of climate-smart agriculture practices in degraded landscapes in Machubeni, Eastern Cape, South Africa
Get PDFOver the last two decades, climate-smart agriculture (CSA) has been promoted as a way to address the challenges of climate change for smallholder farmers' productivity, food security and livelihoods. Given concerns about climate change, many studies have contributed to developing an understanding of resilience building and crop and livestock systems adaptation. Despite evidence of the effectiveness of CSA practices, several studies report on their limited uptake by farmers involved in various projects. The reasons for low rates of adoption remain unclear. In this context, the study on which this thesis is based drew on Bhaskar’s critical realism and Archer’s social realism to explore the way smallholder farmers in five villages in a rural area in South Africa were enabled and constrained as they exercised their agency in a project intended to introduce them to CSA practices. The study was not about adaptation and resilience building per se but rather, following Bhaskar and Archer, sought to identify the generative mechanisms enabling and constraining the adoption of CSA practices. Bhaskar’s critical realism posits a view of reality as layered. The topmost layer of reality is the Empirical. This consists of observations and experiences of the world around us and is understood to be relative. The second layer, the Actual, is the layer of events from which observations and experiences located at the level of the Empirical emerge. Events at the level of the Actual and experiences and observations at the level of the Empirical emerge from an interplay of mechanisms at the deepest layer of reality identified by Bhaskar, as the Real. In positing a layered ontology, critical realism allows for the relativity of experiences and observations while, at the same time, acknowledging the reality of structures and mechanisms, which cannot be directly observed but nonetheless exist. Archer’s work on agency accords personal powers and properties (PEPs) to all individuals. Although all individuals have the power to act in relation to the world around them, they are nonetheless conditioned by their previous histories and experiences as they do so. As individuals set about exercising their agency, they are enabled or constrained by structures and mechanisms in two domains at the level of the Real which are understood to possess their own powers and properties: the structural domain and the cultural domain. In addition to drawing on Archer’s conceptualisation of the interaction between agency, structure and culture, the study also uses her “morphogenetic framework” which allows for the identification of ‘whose conceptual shifts are responsible for which structural changes, when, where and under what conditions’ (Archer, 1998: 361) and for understanding change as a series of never-ending cycles. The first phase of Archer’s morphogenetic framework, entitled T1, involves social and cultural conditioning. In the study, T1 was understood to be the time until 2017 when the project on which the study focused began. The second phase, T2 to T3, is the phase of social and cultural interaction as agents exercise their PEPs to pursue concerns they have identified for themselves and encounter structural emergent powers and properties (SEPs) and cultural emergent powers and properties (CEPs) of mechanisms located in the domains of structure and culture as they do so. The final phase of the framework, T4, allows for an evaluation of what has changed and what has not changed. My claim is that the uptake of CSA practices is impacted by different forms of consciousness or ways of experiencing the world, which is the result of the social and cultural conditioning of different groups involved in the project at T1, and clashes between them. The use of the framework drawing on critical realism and social realism allowed for the identification of these different forms of consciousness in different social groups (project facilitators, elderly farmers and the youth). These different forms of consciousness were understood to condition the agency of the three groups and thus enable or constrain the introduction of CSA practices and how they were taken up. Elderly women in the project had been conditioned to be caregivers and to see their roles tending kitchen gardens as part of their identity. This consciousness led to the uptake of CSA practices in their home gardens. By contrast, young people engaged with the project shared a very different way of experiencing the world. They were better educated and had been socialised into using social media and watching films on electronic devices from a young age. As a result, they valued the role of money in accessing consumer goods and the good life and thus valued paid employment rather than working on the land to provide subsistence. This led to a limited uptake of CSA practices. It is envisaged that insights from the study will offer new ways of understanding what might otherwise be seen as resistance to adopting CSA practices as well as new ways of engaging with different groups of agents involved in projects in the future. The study demonstrates the explanatory power of critical realism and social realism to analyse a climate change adaptation project.Thesis (PhD) -- Faculty of Science, Environmental Science, 202
The development of dual-action antimalarial compounds
No full textAccess restricted. Expected release in 2025.Thesis (PhD) -- Faculty of Science, Chemistry, 202
Screening for inhibitors of the Mycobacterium tuberculosis DnaK-DnaJ-GrpE complex
No full textRestricted access. Expected release in 2026.Thesis (PhD) -- Faculty of Science, Biochemistry, Microbiology and Bioinformatics, 202
Technological pedagogical content knowledge: an examination of rural secondary school life sciences teachers’ integration of technology in Eastern Cape province
Get PDFRural education, particularly in the Global South, faces distinct challenges flowing from low socio-economic conditions, limited resources, and inadequate funding. These issues notably affect rural teachers’ abilities to deliver quality education. Although technology integration offers potential benefits and rural teachers have increased access to various technologies, they frequently adopt these tools spontaneously without guidelines. While many teachers in rural schools choose specific technologies to address teaching challenges, technology has to be integrated with a clear pedagogical intent. The rural teachers’ frequent adoption of technologies hints at technological pedagogical content knowledge (TPACK) development, consciously or unconsciously. However, the process of developing this expertise remains largely unknown. Furthermore, the development of TPACK among teachers in rural Global South schools, particularly those who did not receive formal or informal technology training during their initial teacher education or professional development, remains unclear. Therefore, this research delved into the practices, factors, and experiences influencing the development of TPACK, all from the perspective of Life Sciences teachers in rural schools. The voices of teachers in rural regions have been notably absent in the broader discourse of TPACK research, making the current study’s insights particularly significant. This qualitative and investigative study, located within the interpretivist paradigm, is grounded in Vygotsky’s (1978) socio-cultural theory and Koehler and Mishra’s (2006) Technological Pedagogical Content Knowledge framework. Seven Life Sciences teachers participated in the study. The teacher participants were purposively sampled from schools in the Joe Gqabi district in the Eastern Cape province of South Africa. Multiple data-generation instruments were employed. These included a questionnaire, semi-structured interviews, lesson observations, and sharing circle discussions. A thematic analysis approach, guided by the study’s dual theoretical perspective, was applied to dissect and analyse the data. The study’s findings challenged the prevailing assumption that rural schools lack access to technological resources, unveiling that rural Life Sciences teachers in this research had access to diverse educational technologies. Nevertheless, despite improved technology accessibility, these teachers predominantly employed ‘simple skill-based’ technologies for content delivery, resulting in limited learner engagement. Notwithstanding the challenges posed by inadequate school infrastructure, limited electricity access, and poor Internet connectivity, this investigation found that Life Sciences teachers in rural settings who lack formal technology integration training demonstrated enthusiasm for incorporating technology into their teaching methods. Furthermore, these teachers exhibited strength in non-technological TPACK domains, such as content knowledge (CK), pedagogical knowledge (PK), and pedagogical content knowledge (PCK), while demonstrating limited expertise in technology-related domains, such as technological knowledge (TK), technological pedagogical knowledge (TPK), and technological pedagogical content knowledge (TPACK). The study uncovered nuanced factors, practices, and experiences contributing to TPACK development among rural Life Sciences teachers. These include learning from their learners, collaborating with peers, and engaging in self-directed learning. The study also proposed a new theoretical perspective to the existing TPACK framework to cater for technology integration in rural school contexts. Overall, this research provided a unique perspective on TPACK development in rural schools, particularly in the Global South. The study recommended targeted investments in professional development, promoting peer collaboration, and fostering a culture of self-directed learning. Furthermore, the current research emphasised the importance of recognising the evolving educational landscape as a two-way knowledge exchange between teachers and learners to foster TPACK development in rural schools.Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 202
Double jeopardy: reflections of accessing and navigating public spaces during COVID-19 by blind and visually impaired (BVI) people in Gqeberha
Get PDFDisability only exists in reference to ability, denoting that people are only disabled if considered and treated as disabled. The inherent social conditions and features of society significantly shape disability. The impact of the COVID-19 pandemic was significant in the lives of blind and visually impaired individuals (BVI) since these individuals “access the world” through tactile contact, a behaviour strongly opposed during the pandemic. Therefore, this study explored how BVI individuals struggled to access and navigate public spaces in Gqeberha and how their risk of contracting COVID-19 increased when accessing these spaces. The study was qualitative ethnographic research. It was conducted in Gqeberha and embedded within a non-governmental organisation (NGO). A heterogeneous purposive sampling method was used to recruit ten BVI individuals and four trainers. Data was generated through semi-structured interviews and participant observation and analysed thematically. The study's key findings demonstrate that the COVID-19 countermeasures implicated the lives of BVI individuals, as some felt the need to avoid public spaces not by choice but by obligation to protect themselves from the possible risk of infection. The research findings reveal the barriers encountered through social encounters, physical navigation of the built environment, and information access, thus making the social, digital, and physical spheres inaccessible. COVID-19 exacerbated these barriers while simultaneously revealing the perpetual debilitating barriers in the lives of BVI people before the pandemic, during the pandemic, and presently. The recommendations explored the implementation of awareness-based programmes, integration and inclusion in physical spheres, and inclusionary disaster communication during disasters. Ultimately, as a society, we have a lot to do to achieve accessibility and, fundamentally, social integration. It is recommended that when developing health safety policies in times of crisis, it is crucial to consider populations with unique challenges rather than having a blasé approach.Thesis (MSocSci) -- Faculty of Humanities, Anthropology, 202
Figuring the black femme fatale: analysing black womanhood in U-Carmen eKhayelitsha
Get PDFIn this thesis, I investigate black womanhood in U-Carmen eKhayelitsha, a post-apartheid film opera. The aim of this research is to examine the representation of black women in this film opera, focusing largely on the lead character, U-Carmen. This thesis is driven by a form of intersectional feminism which is characterised by overlapping categories such as race, gender, class and sexual orientation (Crenshaw 1989). A growing number of scholars have written about the rise of South African operas (Roos 2012; André 2016; Gerber 2021) but have seldom focused on the multi-layered representation of black women, which is what this thesis aims to do. In reading this work, I argue that U-Carmen eKhayelitsa foregrounds U-Carmen as a black woman with a storyline that rejects essentialists portrayals of black women on opera stages. The film opera, I argue, figures a complex womanhood represented in voice, labour, motherhood, and death. It not only recognizes the marginalised, but it also offers a change to the perception of the gendering of the black female body. In this thesis, I employ textual analysis to consider the historical contexts of U-Carmen alongside its contemporary resonances and analyse the main female character in the opera and how she can enforce or change the narrative of the role of women in opera.Thesis (MA) -- Faculty of Humanities, Music and Musicology, 202
“What’s good fam?”: African digital sociality and notions of community and family in the UCKAR Facebook group
Get PDFThis study explores the digital sociality of the UCKAR Facebook group. This student Facebook group was formed during the 2015 #RhodesMustFall period. The acronym UCKAR stands for the “University Currently Known As Rhodes” and signifies hope for the transformation of the university. Qualitative interviews were conducted to investigate how UCKAR Facebook group understood and interpreted their sociality, i.e. what do they mean when they say “we” or “us”; how such understandings emerged from group membership descriptions and interpersonal obligations as well as the actual social interactions and participation in the group through digital practices, that is, posting and commenting. A qualitative thematic analysis was undertaken through grouping together representations of various notions of the nature and purpose of their Facebook group as a social space, or its sociality. The findings revealed how various digital socialities co-exist in the same digital space. They reflect different ways in which group members can relate to each other meaningfully: either as fellow students, activists, student entrepreneurs and customers, caring community members or fellow revellers. I refer to these socialities as “Rhodent sociality”, “comrade sociality”, “hustle sociality”, “ubuntu sociality” and “groovist sociality”. These socialities are evidentially not mutually exclusive, and members can and do engage in multiple socialities within the group or shift amongst them depending on the situation. In this analysis, these socialities are linked to the existing scholarship on digital socialities. The findings suggest that the resilience to survive in an alien cultural space does not only demand a digital space that supports rational political resistance and practical tips to navigate the space as seen in the “comrade sociality” and “Rhodent sociality”. It also requires a digital space which can incorporate elements of communal care, economic survival and at times a Bakhtinian carnivalesque outlet to momentarily invert an unjust society . I call this kind of digital sociality a survivalist digital community, which is a form of digital sociality created by persons who need to survive a space that was not designed for people like them, and is underpinned by survivalist knowledge.Thesis (MA) -- Faculty of Humanities, Journalism and Media Studies, 202