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Keychains and preferential fuzzy sets with applications
No full textIn this thesis, we study the preferentiality behaviour of choices under uncertainties using keychains, where a keychain is defined as an (n+ 1)-tuple of non-increasing real numbers in the unit interval, I= [0, 1]. We look at the representations of uncertainties or sets defined by vague properties using the idea of keychains, pins and pinned flags. We then apply the ideas of preferential fuzzy sets to voting patterns, economics and decision making. For voting patterns, we simulate mock trials to investigate the behaviours of choices of different individuals, the outcomes of such voting and make specific conclusions about voting strategies. It can be argued that preferentiality in voting can enhance the democratic processes in national elections. This thesis contains various representations of keychains such as binary digits, weight order, lattice and simplex representations. Another useful aspect of keychains and preferential fuzzy sets is to study the outcomes of decision making linking it to the study of keychains and finite fuzzy sets. We envisage that this study will throw light on computational aspects of any countable situations.Thesis (PhD) -- Faculty of Science, Mathematics, 202
The impacts of bottom-up and top-down drivers in shaping the herbivore community in Pafuri, Kruger National Park, South Africa
Get PDFGlobally, terrestrial mammal populations are facing critical population declines and range contractions owing to habitat fragmentation and destruction, wildlife overexploitation, and climate change driven by expansion of the human population. Mammalian herbivores are integral for maintaining ecosystem structure and functionality. They do this this through herbivory, by acting as prey and cycling soil nutrients. The impacts of herbivores on ecosystems, however, vary with their spatial occupancy which is influenced by interacting bottom-up and top-down factors. Modelling the drivers of herbivore communities is no trivial task given the myriad of potential bottom-up and top-down factors, and the interactions between the two, as well as the species-specific variations in intrinsic functional traits (e.g., foraging strategy, body size, metabolic rate, etc.) influencing herbivore responses (e.g., social structure, space-use, activity patterns, etc.) to these drivers. Consequently, few studies have attempted to model both bottom-up and top-down drivers in structuring herbivore communities, particularly in an African context where predator-prey guilds include multiple species, exposed to high levels of human activity. Therefore, the overarching aim of my research was to quantify the relative effects of both bottom-up and top-down factors driving the herbivore community in the northern Pafuri region of Kruger National Park, South Africa. I utilized a combination of field (i.e., camera trap and vegetation surveys) and analytical (i.e., stable carbon isotopes from faeces and plants) techniques in conjunction with geospatial data to evaluate the impacts of bottom-up (i.e., forage quantity, quality, and water availability) and top-down (i.e., predation and anthropogenic risks) factors on herbivore spatial occupancy and activity patterns. Herbivore responses to bottom-up and top-down factors were species-specific, even among members of the same feeding guild. Specifically, I found that herbivores (varying in body size and foraging strategy) displayed temporal, spatial and in some instances, dietary shifts that reflect species-specific, ecological trade-offs between resource acquisition, and predator and human avoidance. For example, kudu (Tragelaphus strepsiceros) displayed temporal and spatial avoidance of predators and humans, and exhibited previously undocumented levels of seasonal dietary shifts which suggests that the species traded forage acquisition for reduced predation and anthropogenic risks. Further, high levels of human activity appeared to eclipse the risks associated with natural predators resulting in human induced landscapes of fear. For example, warthogs (Phacochoerus africanus) and zebra (Equus quagga) occupied habitats with higher predation risks, but displayed spatial avoidance of nature reserve boundaries which were synonymous with high levels of bushmeat poaching. Most studies focussing on the impacts of bottom-up and top-down drivers neglect to consider the roles that humans play in structuring ecological communities. The results of my thesis, however, emphasize the importance of including anthropogenic drivers when investigating the roles that various bottom-up and top-down factors play in shaping ecological communities.Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 202
Inhibitory effects of selected cannabinoids against dipeptidyl peptidase IV, an enzyme linked to type 2 diabetes
Get PDFEthnopharmacological relevance: In recent times the decriminalisation of cannabis globally has increased its use as an alternative medication. Where it has been used in modern medicinal practises since the 1800s, there is limited scientific investigation to understand the biological activities of this plant. Aim of the study: Dipeptidyl peptidase IV (DPP-IV) plays a key role in regulating glucose homeostasis, and inhibition of this enzyme has been used as a therapeutic approach to treat type 2 diabetes. However, some of the synthetic inhibitors for this enzyme available on the market may cause undesirable side effects. Therefore, it is important to identify new inhibitors of DPP-IV and to understand their interaction with this enzyme
Language Revitalisation and Community Broadcasting in South Africa: A Case of Vaaltar FM
No full textThis chapter deals with indigenous radio broadcasting by considering a Setswana language community radio station as a case study. The aim is to examine the role these stations have played in South Africa over the decades and their contribution to revitalising indigenous languages. The study draws influence from indigenous radio stations as a catalyst for protecting and preserving languages from total extinction. The station considered is Vaaltar FM. Using the theories of language revitalisation and translanguaging, the chapter will discuss strategies endorsed by indigenous radio stations in South Africa to revitalise indigenous languages. While some radio stations, especially public service broadcasting radio stations, revitalise standard indigenous languages, some community and commercial radio stations, such as Vaaltar FM, do the same by employing complex situated, processual and interactional communicative practices such as translanguaging. These differing approaches expose the long-standing tension faced by radio stations aimed at indigenous-speaking South Africans regarding whether they remain traditional in their approach or adapt with the times and incorporate modernised elements that, to some, are a dilution of their cultural heritage
A systematic revision of Aprionyx Barnard, an endemic South African genus of Leptophlebiidae (Ephemeroptera)
Get PDFAprionyx Barnard, 1940 is the most speciose genus of Leptophlebiidae in South Africa and endemic to the southern region. Like the other African Leptophlebiidae, Aprionyx has received limited research. The earliest described Aprionyx species were based only on adults that were then placed in Atalophlebia Eaton, 1881. The first descriptions of nymphs were contributed by Barnard (1932), with the smooth claws of the nymphs being the distinctive feature that allowed him to create Aprionyx for all of the South African species placed in Atalophlebia at that time. This research aimed to improve knowledge of Aprionyx species by revising its molecular and morphological systematics. Molecular phylogenetic analysis of the COI, 16S and 28S genes generated a species tree illustrating the species’ relationships within Aprionyx. Species delimitation analyses (bPTP and GMYC methods) were generally congruent with the molecular phylogenetic species composition. The phylogeny identified up to ten potentially new species, a substantial increase in the species diversity of Aprionyx. Review of the descriptions of the eight named Aprionyx species resulted in major nomenclatural changes concerning A. tabularis (Eaton, 1884), A. phoeocera (Lestage, 1924) stat. rev. and A. intermedius Barnard, 1932 n. syn. With the redescriptions of all currently known species, the nymph of A. rubicundus Barnard, 1932 was described for the first time. An identification key to the species of Aprionyx was compiled from newly recognized descriptive characteristics and, for the first time, includes both imagos and nymphs. Molecular and morphological phylogenetic analyses recovered Aprionyx as monophyletic, although this was poorly supported morphologically. The phylogenies were topologically congruent and identified two clear geographically separated clades, a western and eastern Aprionyx group. Molecularly, morphologically and geographically, these two clades were recovered as two clearly distinct groups within the genus. The analyses further identified three lineages in Aprionyx: rubicundus, pellucidulus and eastern Aprionyx. The estimated age of Aprionyx indicated that initial diversification occurred during the Cretaceous (approximately 100 ma). Aprionyx peterseni (Lestage, 1924) was shown as the oldest of the analysed species, and the main drivers to species diversification were possibly the glacial cycles of the Quaternary period, through the mechanism of river anastomosis during fluctuating sea levels. Further research is needed to strengthen the support for the hypothesis identified in this study, but a substantial foundation has been laid by this work for future research, conservation and environmental decision-making.Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 202
Family language policy in a xenophobic context: The case of Kalanga transnational families in South Africa
No full textDue to globalisation and people’s mobility, transnational families have become a common feature worldwide. As they settle in host countries, a diminished need and opportunities to use their heritage languages usually follow. This tendency places pressure on immigrant languages, particularly in countries that do not support their teaching in education. In highly ethnicised and racialised contexts like South Africa, parents’ transnational experiences impact decisions regarding language use in identity construction in the host country. This study examines the family language policies of three transnational Zimbabwean Kalanga families in South Africa. It reveals how their language transactions, negotiations and contestations are enmeshed with considerations of the everpresent xenophobic sentiment in South African society. Data were collected through semi-structured interviews with parents from three focal Zimbabwean families of Kalanga heritage. The findings show that parents’ experiences of xenophobia in South Africa shape their language acquisition decisions for their children in considerable ways. The preference for acquiring and using Zulu and English at the expense of Kalanga is motivated by parents’ desire and aspiration for their children’s assimilation into a South African identity to minimise exposure to xenophobic attacks, for children’s schooling and general upward social mobility
Restless imagination: material, urban space and contemporary art practices in postcolonial Harare
Get PDFThe use of everyday objects as art materials has evolved into a contemporary phenomenon in Africa, deeply rooted in specific contexts and possessing global relevance. Despite limited scholarly attention, existing discussions tend to revolve around individual artists or particular mediums. Many discourses are associated with either the prevailing universalist perspective that views the trend as Western avant-garde derivation or the reductionist narrative that attributes it merely to local material scarcity. There exists a critical need to investigate historical genealogies and explore the theoretical frameworks essential for comprehending this phenomenon. Through a combination of visual analysis, fieldwork and interviews, this thesis conducts an in-depth examination of the use of found materials in Zimbabwe, exploring its historiography, mechanism, impact, and visual achievements. This thesis situates the investigation in postcolonial Harare, the city that profoundly shaped the evolution of the phenomenon of using found materials. Regarding timeframe, this thesis examines contemporary Zimbabwean artists’ practices, with a special emphasis on the period following the Redefinitions movement in the early 2000s. However, it also explores the pioneering material innovations of Tapfuma Gutsa and Keston Beaton, as well as analyses the importance of the Pachipamwe workshop between the 1980s and 1990s. Among the artists, it highlights those who consistently engage with found materials and delve into their interactions with urban spaces in their practices. With the city as the analytical framework, this thesis draws on debates centring on contemporary African art and theories about materiality and urban studies. Approaching found materials as the materiality of both art and the city, it reveals a convergence of various interrelated artistic practices in Harare. The multidimensional relationships are manifested in the artistic processes, where the collection of materials, the creation of artworks, and collaboration with diverse urban groups, are intricately linked to urban spaces in Harare. By unfolding this process and emphasising the labour of artists, this thesis transcends conventional perceptions of artworks as mere visual objects, revealing the societal and spatial interactions inherent in artistic practices involving found materials. This thesis also explores the visual and semantical interactions between art and the city, centring on a curated array of artworks which is not merely a visual representation or reflection of the city but also provides critical thoughts on and dialogues with the city, as well as (re)imaginations and aspirations of the urban landscape. The relationship between art and the city is further deepened through iii artistic practices, extending beyond the creation of artworks and involving art infrastructure building in Harare. This thesis conceptualises artists’ practices of working with found material as restless imagination, a term drawn from the name of the city, which refers to “no one sleeps” in the Shona language. The restlessness embedded in its naming has characterised the city in various dimensions and across time, with the haunting colonial legacy, ongoing urban crises, ubiquitous movements and the ordinary people’s unwavering efforts for liberation and survival. Artists residing in postcolonial Harare also adopt and cultivate restlessness as a working strategy not only to cope with but also to transgress such conditions. The evolution of found materials has been unfolded through a continuous process of restless imagination and innovative manoeuvres, which are embodied in the continual re-imagination of the convention of art materials, the expressive capacities of specific materials, and a commitment to labour throughout the transformative process. This open-ended though productive process of exploration perpetuates and extends to the re-imagination and reclaiming of urban spaces, transforming them into artistic spaces that foster artistic creation and the reproduction of artists and imaginations. This thesis argues the potential framing and comprehension of Harare city as the site of restless imagination pursued, embodied and materialised by artists through their artwork and engagement with urban spaces. Contemporary Zimbabwean artists have redefined their artistic practices, interacting with the materiality of everyday urban life, urban matters, urban spaces, and urban communities, and, concurrently, the relationship between art and city, art and society. By doing so, they open up space for possibilities to refashion the restless city, negotiate urban citizenship, and recreate themselves as agentive subjects in postcolonial Harare. It could be argued that artists, as urban citizens, akin to other residents grappling with everyday life in the city, also exercise their arts of citizenship through their creative innovations in artistic expression and practices. Therefore, this thesis not only delves into the contextualisation of artistic practices in Harare but also contributes to broader discussions on everyday practices in African cities through the lens of art.Thesis (PhD) -- Faculty of Humanities, Fine Art, 202
Teachers’ use of authentic tasks through mathematics trails in a mobile learning environment to facilitate conceptual teaching
Get PDFThe teaching and learning of mathematics in Namibia is confronted by various forms of challenges that require continuous search for effective pedagogical strategies and approaches to enhance mathematical understanding. Some of the ways include using real and authentic outdoor activities and technological tools, such as smartphones, for teaching and learning purposes. The need to use authentic and realistic tasks in outdoor settings in the teaching of mathematics has strong support from the literature. Moreover, many recent reforms in education challenge teachers across all subjects to use modern and up-to-date technologies to complement and support existing approaches to teaching. Smartphones, in particular, offer new opportunities in the evolution of technology-enhanced learning by allowing teaching and learning to occur in authentic and realistic contexts that extend to real-life environments. This qualitative case study proposes a practical framework that can facilitate mathematical understanding in teaching through the implementation of authentic and realistic outdoor tasks by using the Math City Map (MCM) project on a smartphone. The study aims to analyse and understand how mathematics teachers can create and implement authentic and realistic tasks in an outdoor mathematics trail to facilitate the conceptual teaching of area, volume, ratio and proportion topics, within the context of the Realistic Mathematics Education theory (RME). The study is framed within the RME theory and the iPAC (personalisation, authenticity, collaboration) mobile pedagogical framework. The research process is underpinned by an interpretivist paradigm. Data was collected from eight selected teachers through observations and interviews and analysed using frameworks derived from the RME and iPAC mobile pedagogical theories and the emergence of common themes. The findings suggest that the integration of smartphones and mathematics trails have pedagogical benefits in mathematics teaching and can facilitate the use of outdoor tasks that are connected to learners’ realities. The study argues that while MCM mathematics trail tasks can be difficult to create, it was worthwhile for teachers using them to conceptually teach the selected topics. It is therefore hoped that the findings of this study contribute towards the use of outdoor mathematics trails and smartphones in the teaching of mathematics.Thesis (PhD) -- Faculty of Education, Secondary and Post-School Education, 202
An analysis of the precarious livelihoods of Zimbabwean migrants in the informal economy in Makhanda, South Africa
Get PDFThe movement of people across borders is a complex phenomenon that has far-reaching social, political, and economic implications. In recent years, Zimbabwean migrants have become increasingly visible in the informal economy across South Africa. Through qualitative data collection methods, this study sought to broaden our understanding of the precarious livelihoods of Zimbabwean migrants working in the informal economy in South Africa. This study examined Zimbabwean migrants in the informal economy in Makhanda, Eastern Cape in South Africa. Underpinned by the Sustainable Livelihoods Approach (SLA) as the theoretical anchor, this thesis offers a comprehensive examination of not only the challenges but also the opportunities faced and presented to Zimbabwean migrants in the informal economy in Makhanda. The Sustainable Livelihoods Approach was used as a framework to guide the analysis aimed at understanding the precarious livelihoods of Zimbabwean migrants working in the informal economy in terms of the vulnerability context they find themselves in, the assets they use, the organizations or institutions that affect their activities and the results they get out of their efforts in the informal economy. Data was collected from a sample of 10 participants, consisting of 4 self-employed participants and 6 “employed” in the informal economy. Through in-depth interviews and thematic analysis, this thesis examined the strategies that the migrants adopt to cope with the challenges they face and the impact that these strategies have on their livelihoods. The findings suggest that working in the informal economy evolves as a sustainable livelihood strategy, which depends on external support for it to flourish.Thesis (MSocSci) -- Faculty of Humanities, Sociology, 202
The development of mobile money services and financial inclusion in Zimbabwe
Get PDFPurpose- The use of mobile phones in Zimbabwe fostered the development of various financial innovations, such as mobile money services. It is important to note that the use of mobile money services in Zimbabwe has gradually increased. This study was carried out to determine the relationship between the development of mobile money services and financial inclusion in Zimbabwe. The main goal was to determine if there is a correlation between financial inclusion and the development of mobile money services. Design and Methodological approach: This study used a quantitative research design in which time series data was used to generate the analysis. The data used in the study covered a period of 20 years, starting from 2000 to 2020 on a yearly basis. Auto Regressive Distributed Lag (ARDL) Model was used to analyze the relationship. Findings: The ARDL study results showed that in the long run, there is no statistically significant correlation between the development of mobile money services and financial inclusion, and this is suggested by the long-term relationship between the two variables over a period of 20 years. In the short run, the study findings showed that the development of mobile money services have a positive significant influence on financial inclusion with. Therefore, increase in mobile money usage was associated with increase in financial inclusion. Between the period 2000 and 2020, the major determinants of mobile moneys services are age, number of ATMs, financial literacy, income level and mobile phone penetration. The tests also showed that these variables significantly and positively influenced use of mobile money as a financial inclusion tool in Zimbabwe (p<.05). Research Limitations: The study did not find a lot of current relevant literature that would explain the relationship between mobile money services and financial inclusion. Majority of the work was carried out in other countries, and little was covered in Zimbabwe. Practical Implications: The study results implies that government should put in place measure to ensure the expansion of mobile money services in the rural areas. The mobile telecommunication firms should ensure increased mobile phone penetration.Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 202