VIVA Comrade Moss
- Authors: NUMSA
- Date: 25 April
- Subjects: NUMSA
- Language: English
- Type: text
- Identifier: http://hdl.handle.net/10962/109640 , vital:33163 , SALHA 14b : NUMSA
- Description: The last 'Trial Update" reported on Comrade Moss’s case until mid-March. This report covers the period from that time up until 25th April.STADLER - "ANC EXPERT" Brigadier Stadler testified that the ANC had made certain calls to organisations within the country which, according to his "research", had been followed by organisations in the country. As examples he gave the ANC’s call for ungovernability, the formation of organs of people’s power and the destruction of town councils. During cross-examination Stadler conceded that he was not able to give examples of any direct link between the ANC and organisations inside the coutry but he said an inference could be drawn by looking at the ANC’s call and the behaviour of organisations inside the country.
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Honorary Citation for the Conferment of Doctor of Laws honoris causa - Tandabantu Tennyson August
- Authors: Rhodes University , Martin, Tom
- Date: 2024-14-05
- Subjects: Uncatalogued
- Language: English
- Type: Speeches , Transcripts, speech , text
- Identifier: http://hdl.handle.net/10962/432591 , vital:72885
- Description: Rhodes University Honorary Doctorate Citation (5 April 2024) Tandabantu Tennyson August: 1980s. South Africa. In the Bantustans of the time, like the Transkei, the youth have little reason for hope. They have much reason for despair. Their choices seem limited to the politics of struggle or to crime, an attempt to gain some kind of advantage from the meagre and unacceptable options on offer. In those bleak times, what was needed was visionaries. People who could see beyond the current circumstances to a different future and imagine how best to prepare for it. Not as idealists, but as pragmatists. What would happen once circumstances change, once the struggle had succeeded? Would we be ready for it? What qualities would the youth need to have in order to both benefit from and participate in a new dispensation? One such visionary was Tandabantu Tennyson August, and it is my distinct pleasure to have the opportunity to tell you more about him. Born in 1948, Mr. August matriculated from Healdtown High School, before pursuing higher education at the University of Transkei, where obtained a Bachelor of Arts degree majoring in English and Geography. This was followed by Comparative Curriculum Studies at the University of South Africa, alongside obtaining teaching certificates from Lovedale and Cicira teacher training colleges, with majors in Physical Science, Mathematics, Science, and Mathematics. This solid educational foundation laid the groundwork for his impactful career in education. He taught at Wongalethu High, St Johns College and was deputy principal at Norwood, before taking up his first principalship, at Thanga High School in 1980. From 1984 to 1990 he was principal of Ndamase High School. During his tenure there, the matric pass rate never fell below 90%. From 1991 to 1995 he was principal Isivivane High School during which time the school was promoted from a primary to a high school. Following his distinguished service at schools, he worked at the Eastern Cape Department of Basic Education, first as a deputy chief education specialist (1996 – 2006) and then as chief education specialist (2006-2010). During that time, he played a pivotal role in establishing (in conjunction with Rhodes University) and being the provincial coordinator the Advanced Certificate in Education in English, followed by ACEs in mathematical literacy and life orientation. In 2016 he received a provincial teaching award for excellence. In 2017 he was awarded the Kade Asmal award for excellence in teaching. To this day, he remains an Executive member of the eastern cape Education advisory council. Quite a career. But there’s something I haven’t mentioned. He was also an accomplished rugby player of international standing. While at Lovedale College, he was selected to represent Border and then the South African African Rugby Board, playing England in Gqeberha in 1972, in a team that would later be known as the black springboks. He eventually received his green and gold springbok blazer as just recognition of his achievement. He incorporated his love of sport into his vision for the youth under his care, as part of his overriding mission of educating the whole person. He got everyone involved in sport, if not as a player, then as a supporter. Especially during his time as principal of Ndamase High School, I am led to believe, it was extremely intimidating for opposing teams to play them. Not only at Ndamase home games, but especially at their away games. There would be one bus for the team players, and six buses for the supporters. From 1986 – 1990: he was president of the Transkei schools` sports union (TSSU). But there’s yet another thing I haven’t mentioned. In 1981, just as his career as an educational leader was really taking off, he was involved in a terrible motor vehicle accident. It left him permanently disabled and, for much of his life, a wheelchair user. Rather than stopping him, it simply added another string to his bow, now as an advocate for the disabled. From 2012 – 2022: Chairperson Eastern Cape South African National Association For Special Education (SANASE): this organization cater for the education and wellbeing of learners with disabilities and special needs. In 2023, he was the national deputy president of the same organisation. From 2013 – to date: he is a Board Member on the National Council of & for persons with disabilities (NCPD). I had the pleasure of an extensive conversation with one of Mr August’s former pupils at Ndamase High, Professor Deyi Mbelani, the current director of Rhodes University’s Institute for the Study of Englishes in Africa. He told me many stories about Mr August’s leadership, that I only wish I had time to share with you now. I put it to Professor Mbelani that, having read about Mr August, the word that stood out for me was “dedication.” He agreed that “dedication” was the word, but that I must not leave out another: “vision”. It is Mr August’s status as a visionary that best defines him, he said. Going back over the above, I think he is right. Mr Chancellor I have the honour to request you to confer the degree of Doctor of Laws honoris causa on the Mr Tandabantu Tennyson August. *The above citation draws heavily on documents submitted as part of the honorary doctorate nomination process and others compiled by the Division of Communications and Advancement. - Tom Martin.
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A capabilities analysis: degree mobility and the impact of returning South African alumni on their home country’s sustainable development
- Authors: Mwatunga, Carine Brigitte
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/436570 , vital:73283 , DOI 10.21504/10962/436570
- Description: The significance of sustainable development (SD) has gained increasing attention, particularly since introducing the Sustainable Development Goals (SDGs) in 2015. SDG 4 focuses on ensuring inclusive and high-quality education for all individuals, as well as the provision of equitable access to lifelong learning opportunities. In addition, SDG 4 recognises education as a fundamental element of societal progress and SD. Given the role of education in fostering economic growth, social cohesion, and individual empowerment, SDG 4 is a crucial component of global efforts to foster a more prosperous and equitable world. The primary focus of the study explained in this thesis was to address a specific aspect of Higher Education (HE) within the framework of the SDGs. While SDG 4 covers a wide range of targets, such as expanding scholarship opportunities for individuals from the Global South to study abroad, there remains a lack of comprehensive understanding of how pursuing a degree in a foreign country can influence graduates' potential contributions to sustainable development (SD) upon returning to their home countries. Moreover, despite researchers highlighting the need for attention to this topic, it has not received adequate focus thus far. Therefore, drawing upon the framework of the capability approach (CA) to sustainable development, the study explored whether returning graduates could contribute to SD in South Africa. To integrate the concepts of SD and CA, the study developed a framework for a responsible agent (RA), which was facilitated through previous studies. This framework provides a set of capabilities that are essential for supporting SD in South Africa. Based on this framework, the study comprehensively explored the experiences of postgraduate students and their potential to contribute to SD in South Africa. The study drew on survey data, semi structured interview, and document analysis to gain insights into how the structures of six selected scholarships aligned with SD objectives. However, upon analysing the eligibility criteria of these scholarships, it became evident that they already take into account certain capabilities associated with the RA in candidates. Furthermore, the analysis revealed that these scholarships tend to favour candidates who exhibit the potential to succeed in their professional endeavours. Therefore, this selection bias may exacerbate the existing inequalities within the South African education system. By disproportionately supporting candidates with advantages or resources, the scholarships may inadvertently perpetuate the disparities in educational opportunities and hinder progress toward a more equitable system. After administering questionnaires to alumni who had received these six scholarships, they were asked to voluntary participate in semi-structured interviews. Thereafter, data obtained was combined with document analysis, questionnaires, and interviews were analysed drawing on the RA framework with a narrative inquiry approach. The analysis of the data gathered during interviews with alumni revealed that certain capabilities were demonstrated and developed because of their degree mobility (pursuing degrees in different locations). However, it was also observed that some capabilities were negatively impacted by this mobility. Thus, the findings suggested a nuanced relationship between degree mobility and the development of specific capabilities amongst alumni, warranting further investigation to understand the implications of degree mobility on various capabilities. The investigation of the study revealed that the structure of the selected scholarships is not fully aligned with SD and that some capabilities can be damaged through degree mobility. To ensure that the scholarships truly support SD, they would require restructuring and (1) lowering expectations and preparing alumni for an often rather difficult return to South Africa; (2) limiting the available scholarships to degree programmes that are less or not affordable at all in South Africa; (3) implementing a re-entry strategy for returning alumni to make the return more manageable; and (4) collecting more data to create a deeper understanding about the possible achievements of individual alumni. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning, 2024
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A case study of code-switching in English First Additional Language Foundation Phase classrooms
- Authors: Goliath, Eldrige Justine
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436453 , vital:73273
- Description: Access restricted. Expected release in 2026. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
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A multidisciplinary study to assess the ecology of the Cape sea urchin, Parechinus angulosus, and its emerging use as a bioindicator to monitor coastal resiliency
- Authors: Redelinghuys, Suzanne
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435691 , vital:73179 , DOI 10.21504/10962/435692
- Description: The resilience of marine species in the face of unpredictable climate change stands as a paramount concern for the maintenance of ecological stability. Under such fluctuating conditions, it is critical to understand how organisms mitigate these effects in physiological, genetic, and morphological terms. To that end, this thesis focused on the Cape sea urchin, Parechinus angulosus, employing a multidisciplinary approach encompassing morphology, genomics, and gut microbial diversity to assess its potential as a bioindicator species and elucidate its adaptive strategies in response to varying environmental conditions along the South African coastline. This was achieved through studying their anatomy in order to link observed variation to prevailing local environmental conditions, aided by the species’ wide distribution range which allows insight into adaptations across broad geographic regions and ecological settings. The first empirical chapter, Chapter 3, focusing on eight key morphometric traits of test, Aristotle’s lantern and spines, revealed distinct variation in the Cape sea urchin's morphology between the east and west coasts of South Africa, suggesting the presence of some level of local adaptation to the prevailing environmental factors found on the east and west coasts of South Africa. This points to potential bioindicator capabilities of the species, reflecting adaptive divergence amidst contrasting environmental conditions. Further analysis is however necessary in order to isolate specific physiological trends that may be associated with these morphometric differences, thereby enhancing and tightening their ecological implications. The second experimental chapter, Chapter 4, delved into the genetic structure of the Cape urchin by investigating genome-wide diversity, the presence of cryptic population structure, and spatial patterns of genomic diversity. Moderate genomic differentiation was detected among populations along the eastern and western coasts of South Africa by outlier loci that may undergo natural selection, which could indicate local adaptation to environmental conditions. This pattern hints at adaptive differentiation and cryptic genetic structures within the Cape sea urchin populations and emphasises the species' potential adaptive responses to localised (in this case regional) environmental pressures. Assigning functional significance to these genetic variations will require a comprehensive annotated reference genome, a limitation acknowledged in the current study. Chapter 5 explored the gut microbial diversity and revealed significant compositional variations between the east and west coast populations of South Africa, confirming regional and inter-regional variation. This chapter also highlighted the essential biochemical pathways critical to the survival of the host which is crucial for assessing the health of the urchin host. Together, the functional content of the gut bacteria and microbial diversity showcases its potential as a bioindicator for coastal ecosystem health. Logistical challenges and confounding factors like host physiology will need to be fully considered for its effective application. Overall, the findings of this doctoral research suggest that the Cape sea urchin displays promising characteristics as a bioindicator species due to its morphological, genetic, and gut microbial variations in response to environmental differences, providing a diverse array of means in which urchins could be used as bioindicators, from their uses to assess water quality and detect pollution, to ecosystem health monitoring and biodiversity studies in which sea urchin abundance, distribution, and presence are monitored. Further research, integrating these multidisciplinary approaches is recommended to validate and refine its bioindicator potential. Additionally, the development of a comprehensive annotated reference genome is imperative to harness the species' genetic information effectively. This study underscores the significance of integrating multiple disciplines in understanding how species respond to environmental change and their potentials contributions to monitor ecological resilience. The original multidisciplinary approach, combined with high computational outputs presents a promising framework for a comprehensive ecological monitoring in marine ecosystems. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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A revised checklist of extant freshwater fishes of the Zambezian Lowveld Ecoregion, with taxonomic revision of the lowveld largescale yellowfish, Labeobarbus marequensis
- Authors: Ntokoane, Tholoana
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435943 , vital:73214
- Description: Access restricted. Expected release in 2025. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
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A social realist account of the way academic managers exercise agency in monitoring students’ academic success in South African higher education
- Authors: Dwayi, Valindawo Valile Medicine
- Date: 2024-04-05
- Subjects: Social realism South Africa Eastern Cape , Critical realism , New public management , Academic development , Academic achievement South Africa Eastern Cape , College students Rating of South Africa Eastern Cape , College student development programs South Africa Eastern Cape , Student adjustment South Africa Eastern Cape
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435863 , vital:73207 , DOI 10.21504/10962/435863
- Description: The roots of this thesis lie in discourses which promote the use of academic monitoring strategies for student success in South African higher education. Although access to higher education widened for black South Africans following the first democratic election, this ‘formal’ access (Morrow, 1993) has not been matched by success with annual cohort studies showing that, regardless of the university at which they are registered, the subjects they are studying and the qualifications they hope to attain, black South Africans fare less well than their white peers. Monitoring performance and referring students on to academic support and development structures thus became a strategy identified as having the potential to address patterns in performance data. The study reports on an attempt to introduce a strategy for Academic Monitoring for Integrated Academic Development at a historically black university in South Africa’s Eastern Cape province. It draws on a metatheoretical framework developed from Bhaskar’s (1978, 1998) critical realism and Archer’s (1995, 1996) social realism to do this. More specifically, it focuses on the way managers at the institution exercised their agency in relation to the strategy and identifies the way social and structural conditions, developed from the time colonial settlers first arrived on the continent, worked to constrain the exercise of this agency. Although the focus of the study was on agency, the study revealed a system of necessary contradictions (Archer, 1995, 1996), a system of conflicting beliefs exacerbated by a lack of resources, that led to the implementation of the strategy not being as successful as intended. The study not only illuminates the conditions at one South African university but also adds to the body of work on management in higher education and to critiques of ‘managerialism’. , Eyona ngxam yale thisisi kukuphendla iindlela zokukhuthaza ukusetyenziswa kwamaqhinga ezemfundo okuqwalasela impumelelo yabafundi kumaziko emfundo ephakamileyo aseMzantsi Afrika. Nangona emva konyulo lokuqala lwedemokhrasi abemi abantsundu baseMzantsi Afrika bethe bavuleleka ukuba bafikelele kwimfundo ephakamileyo, olu fikelelo 'lusesikweni' (Morrow, 1993) khange luhambelane nempumelelo yaba bafundi, nanjengoko uphando olujolise kwimpumelelo yabafundi ngonyaka ngamnye lubonisa ukuba aba bafundi bathi nokuba bafunda kweyiphi iyunivesithi, befunda ziphi iikhosi bekwafundela waphi amakhono, abafundi abantsundu basoloko berhuqeka emva xa bethelekiswa nabo bamhlophe. Ukuqwalaselwa kwenkqubela nokudluliselwa kwabafundi kumacandelo enkxaso nophuhliso kwimiba yemfundo kube liqhinga elithe lachongwa njengelunokukwazi ukujongana neepateni zendlela abaqhuba ngayo abafundi. Olu phando lunika ingxelo malunga nenzame yokuza neqhinga lokuQwalaselwa kwemiba yeMfundo ukwenzela uPhuhliso kwiyunivesithi eyayisakuba yeyabantsundu kwiphondo leMpuma Koloni laseMzantsi Afrika. Luqamele ngesakhelo semethathiyori esakhelwe kwi-critical realism kaBhaskar (1978, 1979) kunye ne-social realism kaArcher (1995, 1996). Eyona nto lugxile kuyo yindlela abalawuli neenkokeli zeli zikomfundo eziwasebenzisa ngayo amagunya azo ngokunxulumene neli qhinga, lukwachonga indlela iimeko zentlalo nezeziko, ezamana ziphuhliswa ukususela oko kwathi kwafika abarhwaphilizi kweli lizwekazi, ezasebenza ngayo ekunqandeni ukusetyenziswa kwala magunya. Nangona ugxiliso lolu phando belusemagunyeni, luthe lwaveza uluhlu lwemiba echaseneyo eyimfuneko (Archer, 1995, 1996), uluhlu lweenkolelo ezingqubanayo ezihlutshezwa kukushokoxeka kwezixhobo, nolukhokelele ekubeni ukufezekiswa kweli qhinga kungabiyiyo le mpumelelo ibilindelekile. Olu phando aluphelelanga nje ekugqamiseni iimeko zale yunivesithi yaseMzantsi Afrika, koko lukongeza kumsebenzi osele wenziwe kwimfundo ephakamileyo lukwaphendla ‘ezolawulo’. , Thesis (PhD) -- Faculty of Education, Centre for Higher Education Research, Teaching and Learning, 2024
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An analysis of mathematical connections in the presentations of fraction concepts in Namibian grade 7 mathematics textbooks
- Authors: Sibeso, Pumulo Priscah
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436488 , vital:73276
- Description: This study investigated how selected grade 11 mathematics learners used smartphones with the MathCityMap application to learn trigonometry outdoors for conceptual understanding. The aim of this research project was to explore outdoor mathematics learning for conceptual understanding using smartphones. This case study of grade 11 mathematics learners in Lejweleputswa District in the Free State Province, was informed by the Realistic Mathematics Education theory. The study is grounded within an interpretive paradigm and used the explanatory sequential mixed-method design. Forty-two grade 11 mathematics learners participated in the survey and from these 12 were purposively selected to participate in walking the mathematics trails and interviews. The findings revealed that, while the grade 11 mathematics learners acknowledged the significance and value of using smartphones for learning mathematics, they were prohibited from carrying or using smartphones on the school premises, as part of the school code of conduct. The preferred use of smartphones for learning mathematics was understandable, as the survey was conducted at a time when the COVID-19 pandemic and associated restrictions were still in place. The survey unearthed that among applications for learning mathematics, the MathCityMap application was not known by the learners who participated in the survey. Mathematics trails observations indicated that outdoor tasks were a source of mathematical concepts or formal mathematical knowledge, and enabled learners to reinvent mathematical ideas and concepts with adult guidance. Learners were able to make use of appropriate mathematical models and connections. The mathematics trails ignited robust discussions among learners, and prompted learners to draw from prior knowledge, and recognise and identify suitable mathematical models and shapes from the real-world objects. Learners were able to use multiple representations, make necessary mathematical links, and use their prior knowledge to enhance their trigonometry conceptual understanding. This study concluded that using smartphones with the MathCityMap application could enhance conceptual understanding of trigonometry. The implications for teachers are that learners should be exposed to outdoor mathematics learning using smartphones with the MathCityMap application to improve their conceptual understanding. It is hoped that the results of this study can be used by various stakeholders, who include, inter alia, mathematics subject advisors and teacher training institutions, to enhance learners’ conceptual understanding of mathematics. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
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Augmentation of Aphytis melinus DeBach (Hymenoptera: Aphelinidae) for the control of California red scale Aonidiella aurantii Maskell (Hemiptera: Diaspididae) on citrus
- Authors: De Beer, Ernst Friedrich Ludwig
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435638 , vital:73175 , DOI 10.21504/10962/435638
- Description: Aphytis lingnanensis was reared and tested in South Africa in the early 2000s for augmentation against red scale on citrus and was found to be ineffective. Aphytis melinus is now commercially available and it is important that the efficacy of augmentation thereof on red scale is determined locally. Field trials, fitness assessments and molecular identification on A. melinus from two insectaries were done. Field trials was done in seven, five and six pairs of comparable release and control orchards across the Eastern and Western Cape during the seasons of 2019/2020, 2020/2021 and 2021/2022 respectively. Red scale infestation was monitored and a sample of 20 infested fruit from each orchard was randomly collected every four weeks. Aphytis spp. responsible for parasitism were identified and the percentage parasitism recorded. Results of this study of field trials suggest that the augmentation of A. melinus did not significantly increase the level of parasitism above that of the untreated control. Five repetitions with six replicates of flight and longevity tests were performed with wasps from each insectary. Wasps in the longevity test from two insectaries were kept at 23 °C and 65% RH with honey. Flight tests were performed in tubes of 16 by 30 cm, with a light above a clear, sticky ceiling at 23 °C and 65% RH. On average in five replicates, 65%, 33% and 17% A. melinus wasps were alive on day one, five and 10 respectively. The overall sex ratio was 1.58 for females to males, but 1.05, 2.19 and 2.66 for non-flyers, non-crawlers, crawlers, and flyers respectively. In flight tests for both insectaries combined, only 36.97% of wasps could initiate flight in 24 h while 56.96% remained on the tube floor, and 6.05% attempted to crawl upwards. No significant differences in flight performance were recorded between the two insectaries. Wasps from the local insectary lived significantly longer during the longevity tests but were shorter in transit than wasps from the overseas insectary. COI genes were sequenced and compared against Genbank sequences using BLAST. Molecular identifications did not confirm morphological identifications for all species, indicating unexpected genetic complexity. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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Co-occurrence of Sympatric Poroderma Species
- Authors: Watson, Ralph Gareth Andrew
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/436649 , vital:73289 , DOI 10.21504/10962/436649
- Description: Species exploiting similar ecological niches are expected to adapt their behaviour, which can either promote or hinder coexistence. This study examined the ecological (dis)similarity between the endemic Poroderma africanum (pyjama catshark) and Poroderma pantherinum (leopard catshark) in Mossel Bay, South Africa. The co-occurrence of these species was examined along the ecological axes of time, trophic position and space, between October 2015 and April 2018, through the use of Baited Remote Underwater Videos (BRUV), gastric lavage, and acoustic telemetry. Through the deployment of 197 BRUVs, P. africanum showed a seasonal, higher Relative Abundance (RA = 0.52), occurring more frequently during winter months, while showing an overall decline in RA over the course of the study period. Poroderma pantherinum on the other hand, showed a lower, unseasonal RA (0.20), remaining relatively stable throughout the study period. The BRUV deployments indicated that the two species showed a positive co-occurrence with one other, being sighted in BRUV deployments more frequently together as opposed to in isolation/at random. Acoustic telemetry indicated that the two species were active during different diel periods, influenced by a complex combination of tidal and diel rhythms, while P. pantherinum showed a higher residency compared to P. africanum (P. pantherinum: Continuous Residency Time (CRT)24 = 3.32 days (mean), 95% CI: 2.53–4.11 days; P. africanum: CRT24 = 2.01 days, 95% CI: 1.66–2.36 days). While the two species are sympatric in nature, and have an overlapping, endemic, distribution, acoustic telemetry indicated that 1 ABSTRACT P. africanum showed higher degrees of movement throughout the acoustic receiver array (P. africanum: edge density (ED) = 0.25; P. pantherinum: ED = 0.12); however, certain areas of the bay showed to be of high importance for both species. Both species revealed high levels of intra- and inter-specific variation in both residency and movement behaviour. Gastric lavage indicated partially overlapping trophic niches, between the two Poroderma spp. Poroderma africanum had a generalist diet, dominated by teleosts (Index of Relative Importance (IRI)% = 22.69), octopus (IRI% = 11.48) and discarded bait (IRI% = 64.54), while P. pantherinum showed indications of being a specialist predator, with a diet dominated by cephalopods (IRI% = 83.68). The two Poroderma spp. showed a partially overlapping, but separate trophic niches, while displaying spatial dissimilarity in diet. The study suggests that the two species are able to coexist within the same geographical area through niche differentiation across trophic and temporal ecological axes, with varying spatial use. The intra- and inter-specific differences between the two species may complicate elasmobranch management efforts for these co-occurring endemic catsharks, and as such, efforts should follow either an individual species approach, which is often not feasible, or an ecosystem-based approach, as opposed to considering the genus as a whole. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
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Dancing with(in) possibilities: emerging public and convivial pedagogies for ecological citizenship
- Authors: Skerrit, Hayley Frances
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436510 , vital:73278
- Description: This research project explores ways in which ecological citizenship can be stimulated through collaborative public pedagogy and transgressive learning (t-learning) processes. This research identifies ‘places’ of innovation to cover sections that would usually be described in terms of ‘problem statement’, ‘research focus’, ‘intended outcomes / main contribution’ and ‘theory and methodology’. The Place of Worry is identified through the triple C Crisis (Covid, Capitalism and Climate-Change) which reveal the disconnect to the diverse ecologies (both social and natural) that sustain us. The Place of Possibility demonstrates that through ecological citizenship we can begin to absent absences (De Sousa Santos, 2016) and transform into an embodied response to the triple C crisis. The Place of Emergence transforms these possibilities into practice by demonstrating the place between the worry and the possibility allows for an emergence of a new kind of solution, referred to as the third space within this thesis. The Place of Process delves into the t-learning stories that emerged through research creation and works with iterative feedback and cycles of creation. The unfolding of this t-learning project is guided by the use of metaphor and symbolism as a figuration of macro- and microscopic interactions within these learning fields/ecosystems. Symbolic figuration and speculative metaphor are valuable in this thesis and in my own collaborative meaning-making endeavour as they offer translation protocols for when language fails to embody, the rich embodied experience of this form of learning. The embodiment of this work will help to create restorative care practices through transgressive learning (Lotz-Sisitka et al., 2016) and research creation (Manning, 2016). The study has a particular focus on the emergence of identities and onto-epistemological orientation within the social learning journey towards ecological citizenship and the various ways in which they can be embodied to enable public pedagogy. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
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Developing biological control agents for the management of the invasive tree Robinia pseudoacacia
- Authors: Wolmarans, Abigail
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435717 , vital:73181 , DOI 10.21504/10962/435717
- Description: Robinia pseudoacacia (Fabaceae) is a deciduous tree native to the Appalachian Mountains of North America but has become naturalised and invasive in other countries such as temperate North America, Europe, Australia, and Southern Africa. In South Africa the tree is classified as a category 1B invasive alien under the National Environmental Management Act (NEMBA), which stipulates the species requires some form of control as it has already caused extensive negative ecological and economic impacts. In the invaded range the tree creates monocultures that displace native species and spreads rapidly from suckering roots, making it a proficient invader. The South Africa plant prioritisation system suggests R. pseudoacacia is in the top three species which should be considered for classical weed biological control in South Africa. This thesis investigates which insects known to be associated with tree should be prioritised as candidate agents, as well as offering interesting insights into prioritising insects for weed biological control and using plant phylogenies and available literature to predict insect specificity. To ensure that no candidate biological control agents were already present in South Africa as well as to prioritise which guilds of the tree to prioritise for potential biological control, pre-release surveys were conducted across nine sites where the tree has invaded South Africa. It was found that no insects from the native range of R. pseudoacacia were present in South Africa. Seed surveys revealed that generalist insects attack a sizable proportion (68 %) of the seeds on the trees. In combination with a low seed soil bank (15.8 %) this suggests that seed- feeding agents may be helpful, however, candidate agents which damage leaves should be prioritised due to R. pseudoacacia relying heavily upon vegetative reproduction and much less on sexual reproduction. Leaves may therefor reduce the spread of these invasive trees. The insect assemblages in the native range of R. pseudoacacia are well understood. In addition, several associated insects have unintentionally followed the tree on its global spread, where they are often regarded as pests. The third chapter is therefore aimed at prioritising the known insects associated with the tree in both the native and invaded range. Literature surveys and Harris (1973) prioritisation systems were used to prioritise close to 64 candidate biological control agents down to three foliage- feeding agents, namely Odontota dorsalis (Coleoptera, Chrysomelidae), Macrosaccus robiniella (Lepidoptera, Gracillariidae) and Obolodiplosis robiniae (Diptera, Cecidomyiidae). To further prioritise the six selected agents in Chapter 4, species distribution were modelled with known climatic variables. This was done by using the species known occurrence localities, from both the native and where applicable invaded ranges, to identify which species that would best match with South Africa’s climate. The study showed that O. dorsalis is best suited to survive in South Africa, followed by O. robiniae and then M. robiniella. Collected data aided in the introduction of the prioritised O. robiniae into South African quarantine facilities. Unfortunately, despite several attempts, cultures could not be established, making conventional host specificity testing impossible. Thus, in Chapter 5 we aimed to determine the potential host range of the midge using information from experts in the field of galling insects, literature surveys, agricultural pest lists, and social science platforms coupled with native and invaded range surveys. The list of non-target species to consider as potential hosts was refined by developing phylogenetic trees of closely related Fabaceae that share the same distribution (native and invaded) as R. pseudoacacia. Through the available information gathered, and field surveys of these species, O. robiniae has not been shown to utilise any species, other than those from the Robinoid clade. In addition, the midge has also never been recorded on a number of closely related leguminous fodder and horticultural species growing in close proximity at high densities to R. pseudoacacia - suggesting negligible risk to South African growers of the same species. Host-specificity assessments through field surveys can be regarded as one of the best indicators of the ecological host range, however, this information is difficult to quantify and infrequently available, thus seldom used when determining the safety of a candidate biocontrol agent. In this unique study, using the extensive data collected we are able to show that O. robiniae would be potentially safe for release in South Africa. However, open field tests exposing closely related non-target plant species under natural and semi-natural conditions are planned in Switzerland over the next two years aiming to confirm these conclusions. By identifying and prioritizing potential biological control agents, this research contributes to the development of a targeted and sustainable solution for managing R. pseudoacacia in South Africa. The economic implications of successful biological control include reduced costs associated with invasive species management and ecosystem restoration. Additionally, by mitigating the negative ecological impacts, the agricultural systems in affected regions stand to benefit from enhanced resilience and productivity. Furthermore, the study's approach of using plant phylogenies and available literature to predict insect specificity offers a valuable methodological contribution to the broader field of weed biological control. This methodology can be adapted and applied to other invasive species, providing a framework for efficient and informed decision-making in weed management strategies. In essence, this research not only addresses the specific challenges posed by R. pseudoacacia in South Africa but also provides a template for tackling similar issues in different geographical contexts, thereby contributing to global efforts in sustainable agriculture and environmental conservation. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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Ecological impacts of photoautotrophic Euendoliths on South African mussel beds
- Authors: Dievart, Alexia Madeleine Angèle
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435650 , vital:73176 , DOI 10.21504/10962/435650
- Description: Aphytis lingnanensis was reared and tested in South Africa in the early 2000s for augmentation against red scale on citrus and was found to be ineffective. Aphytis melinus is now commercially available and it is important that the efficacy of augmentation thereof on red scale is determined locally. Field trials, fitness assessments and molecular identification on A. melinus from two insectaries were done. Field trials was done in seven, five and six pairs of comparable release and control orchards across the Eastern and Western Cape during the seasons of 2019/2020, 2020/2021 and 2021/2022 respectively. Red scale infestation was monitored and a sample of 20 infested fruit from each orchard was randomly collected every four weeks. Aphytis spp. responsible for parasitism were identified and the percentage parasitism recorded. Results of this study of field trials suggest that the augmentation of A. melinus did not significantly increase the level of parasitism above that of the untreated control. Five repetitions with six replicates of flight and longevity tests were performed with wasps from each insectary. Wasps in the longevity test from two insectaries were kept at 23 °C and 65% RH with honey. Flight tests were performed in tubes of 16 by 30 cm, with a light above a clear, sticky ceiling at 23 °C and 65% RH. On average in five replicates, 65%, 33% and 17% A. melinus wasps were alive on day one, five and 10 respectively. The overall sex ratio was 1.58 for females to males, but 1.05, 2.19 and 2.66 for non-flyers, non-crawlers, crawlers, and flyers respectively. In flight tests for both insectaries combined, only 36.97% of wasps could initiate flight in 24 h while 56.96% remained on the tube floor, and 6.05% attempted to crawl upwards. No significant differences in flight performance were recorded between the two insectaries. Wasps from the local insectary lived significantly longer during the longevity tests but were shorter in transit than wasps from the overseas insectary. COI genes were sequenced and compared against Genbank sequences using BLAST. Molecular identifications did not confirm morphological identifications for all species, indicating unexpected genetic complexity. , Thesis (PhD) -- Faculty of Science, Zoology and Entomology, 2024
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Exploring and expanding teachers’ gender and culturally responsive practices when mediating learning of chemistry in rural schools in Namibia
- Authors: Haimene, Johanna Shetulimba
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/436535 , vital:73280 , DOI 10.21504/10962/436536
- Description: Gender and cultural dimensions are critical aspects of the education system. Schools are full of gender and cultural stereotypes when it comes to the teaching and learning of science. This calls for the teachers to be gender and culturally responsive in their science classrooms. This is also to ensure that the educational needs of both boys and girls are addressed. The Namibian National Curriculum for Basic Education advocates the application of gender equity at all levels and in every aspect of the curriculum and teachers are central to the implementation of this curriculum. However, while the policy has been formulated at the macro level of the education system, little if any research has been done in Namibia on exploring how teachers are coping with and implementing the curriculum based on gender and cultural aspects. This includes how teachers are responding to gender issues and how they eradicate bias and discrimination to ensure equality and equity for both boys and girls in their science teaching. Against this backdrop, this study aimed to explore and expand Grade 9 Physical Science teachers’ gender and culturally responsive practices in science classrooms when mediating learning of chemistry topics using acids and bases and combustion reactions as examples. The study focused on working with teachers with the purpose of improving their practices through collaborative partnerships and enriching all the participants (teachers and researcher) as they were seen as co-learners and co-researchers. Hence, this study was underpinned by interpretivist and critical paradigms. It adopted a case study research design. Six Grade 9 Physical Science teachers from the Oshikoto Region were the participants in this study. Qualitative data were generated using questionnaires, interviews (semi-structured and stimulated recall), classroom observations and Change Laboratory Workshops (CLWs) in which we co-developed a tool to address gender and cultural responsiveness. Vygotsky’s socio-cultural theory and Engeström’s cultural-historical activity theory (CHAT) were used as theoretical frameworks to surface contradictions or tensions that exist in the teaching and learning process. A thematic approach to data analysis was employed to come up with sub-themes and themes. The findings of the study revealed that the teachers seemed to have an understanding of being gender and culturally responsive when they are mediating their lessons. However, some contradictions constrained them from being gender and culturally responsive. The surfaced contradictions included the lack of examples that are not gender and culturally biased, poor participation of the learners during lesson presentation and low confidence among the learners and language barriers. In addition, the findings revealed that teachers need professional development in interpreting policies and the curriculum and techniques for analysing gender and cultural issues pertaining to the teaching and learning process. Through CLWs, we co-developed a mediational tool that could guide teachers on how to be gender and culturally responsive. The findings also revealed that participation of teachers in the CLWs equipped them with resources on how to be gender and culturally responsive in their classrooms. The study recommends that teachers need to be involved in continuing professional development to support them with the correct interpretation and enactment of the curriculum and other policies. The policy developers need to be in contact with the policy implementers to evaluate the implementation of these policies and provide guidance where necessary. Moreover, teachers need to form professional learning communities in order to share their best practices and transform them. This might assist them in addressing gender and cultural issues that are encountered in the teaching and learning process. , Thesis (PhD) -- Faculty of Education, Secondary and Post School Education, 2024
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Exploring expansive learning and co-management in the uMzimvumbu catchment
- Authors: Kuze, Mzukisi
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/436547 , vital:73281 , DOI 10.21504/10962/436547
- Description: South Africa is a water-stressed country which is currently confronting numerous water challenges which include security of supply, degradation of ecological infrastructure, poor landscape governance and resource pollution. These are compounded by built infrastructure, which is ageing, an increasing population and the impact of climate change. South Africa’s water issues are influenced by a myriad of factors such as weather patterns, governance issues, historical apartheid policies, structural integrity of ecological and built infrastructure, and general provision of services. The most vulnerable members of society usually positioned in low-income communities are the ones who mostly bear the brunt of these harsh conditions. To address water insecurities and challenges, South Africa has defined several Strategic Water Source Areas (SWSAs), which are important for water security in South Africa. The Living Catchments Project (LCP) is a collaborative project, situated in four catchments in South Africa, with the aim to strengthen the enabling environment for the governance of water in South Africa’s strategic water resource areas. The central focus of the LCP is on co-learning and co-creation through communities of practice in order to enable, collaborate, and amplify the practice of transformative social learning and improve the policy advice practice and engagement with the water sector to contribute to the Water Research, Development and Innovation (RDI) Roadmap. This study is positioned in the LCP, which is also a case study for transformative innovation policy and Just Transitioning in South Africa. The aim of this study was to address the need for more substantive understanding of learning in co-management, and the evaluation of such learning, which was identified as a gap in the scientific literature, and which was confirmed through policy review. The study set out to explore expansive learning and co-management in the uMzimvubu catchment, which is one of the SWSAs in South Africa and forms part of the LCP, which in turn is part of the Transformation Innovation Policy Consortium’s cases of Just Transitioning. Cultural History Activity Theory (CHAT) was the foundational theory of this research, with a particular focus on 3rd generation activity analysis (Engeström, 1987), and formative intervention methodology, in which I was positioned as a formative interventionist researcher. I used individual interviews, focus group interviews, field observations, and Change Laboratory methods to identify activity systems, the shared object of activity, and to engage multi-voiced participants in resolution of contradictions to expand their learning. The study also identified indicators of learning relevant to co-management in a LCPs context. Monitoring of learning occurred in two different phases; before the expansive learning process (A-view), and after the expansive learning process (B-view). The Value Creation Framework tool adapted from Wenger et al. (2011) was used to identify indicators of learning. This study shows that the object of co-management of water resources in a catchment can be enhanced through learning platforms and processes that are collaborative and expansive. One of the study’s contributions to new knowledge lies in relation to the expansive learning process and how it expanded the learning around co-management in a Living Catchments Project context. A second contribution of the study shows that the expansive learning process embarked on qualitatively changed the nature of the indicators of learning in the catchment. A better set of indicators was attained following the expansive learning process, which are more aligned with the nature of transformative social learning. The study’s contributions can be summarised as offering insights into learning processes for co-management, as well as evaluation of these learning processes. Although the contributions emerging from this study may be at niche level innovation in the framing of Just Transitions, they have a potential to inform other catchments, where multi-actors are working together on co-management of water resources to secure water provision, as was the case for the uMzimvubu catchment communities who participated in this study. , Thesis (PhD) -- Faculty of Education, Secondary and Post School Education, 2024
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Exploring grade 11 learners’ mathematical problem-solving skills using Polka’s model during the learning of Euclidean geometry
- Authors: Hlupeni, Ratham
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436465 , vital:73274
- Description: The skill of Problem-solving in Mathematics is very imperative. Poor performance by most South African learners in schools and international tests such as the Trends in International Mathematics and Science, calls for emphasis to be placed on problem-solving in the teaching and learning of Mathematics. Euclidean Geometry is perceived, especially by learners, to be one of the difficult components of Mathematics. Thus, the aim of this study was to explore and develop the mathematical problem-solving and geometric skills of Grade 11 learners in Euclidean Geometry. Polya’s model of problem-solving was employed in geometric skills development as a tool for intervention. The concepts Geometry and problem-solving formed the conceptual framework of the study, while the social cognitive theory constituted the theoretical framework. A case study was used as the main research method following a mixed method approach within an interpretivist paradigm. Purposive and convenience sampling methods were used in the selection of both the Mathematics class and the six learners whose work was further observed and analysed. Data about the geometric skills displayed by the learners was gathered using a moderated pre-intervention test; observations; document analysis; a moderated post-intervention test; and focus group interviews. Data was analysed quantitatively using descriptive statistics and qualitatively using thematic analysis. In the pre-intervention test, learners did not bring with them expected geometric skills to the classroom before they were introduced to grade11 Geometry content and when doing problem-solving during intervention, the four stages of model used were not necessarily following each other in a linear sequence with most of the learners not applying the fourth stage “look back”. In the post intervention test, the frequency of use and application of most geometric skills improved in comparison to the pre-intervention test; the frequency of correct and inappropriate application of the skills increased at the expense of incorrect application. Learners appreciated the four stages model and gave their views related to the challenged faced during the use of the four stages model and the challenges revealed include: practice related challenges, challenges specific to certain learners, concept related challenges, curriculum-related challenges, model application challenge, and context related challenges. The study concludes that the effective use of Polyas’ four stages model can yield great results in developing learners’ geometric and problem-solving skills. The study recommends that teachers give more attention to prior geometric knowledge, teaching of geometric theorems, teaching of geometric problem-solving, and the learning environment. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
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Exploring how language teachers’ employment of Reading to Learn (RtL) pedagogy enhances Grade 10 learners’ reading skills
- Authors: Gazide, Sydney
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436442 , vital:73272
- Description: The study aimed to explore how language teachers’ employment of the Reading to Learn (RtL) pedagogy enhances Grade 10 learners’ reading skills. The RtL was designed to address challenges regarding learners’ literacy development which other methods could not successfully address. Unfortunately, poor reading skills in English First Additional (FAL) and home languages (HLs) continue to be a challenge among learners from schools situated within poor socio-economic communities in South Africa. The study employed the six-stage curriculum cycle advocated by RtL pedagogy as a scaffolding interaction cycle in the teaching practice reading development sequence to bridge the gap in acquiring reading skills. The main research question for the study was: How can the language teachers’ employment of the RtL pedagogy enhance the teaching of reading? The study was located within the critical education paradigm which encourages critical thinking, creativity, freedom to appreciate and critical awareness in students. This study generated data through focus group discussions, interviews, and document analysis. The research was a case study involving four teachers selected from a secondary school in an informal settlement with low socio-economic standards. A sample of four grade 10 classes with 45 learners in each class for English First Additional Language (FAL), Sesotho Home Language (HL) and Isizulu Home Language (HL) were used in the study. Purposive sampling allowed the researcher to choose participants who were willing to be part of the project. The Reading to Learn pedagogy developed by Rose was drawn from Vygotsky’s, Bernstein’s, and Halliday’s theories. The findings revealed that RtL was used for the professional development of teachers and a methodology that supported learners to improve their reading skills. Even though the study was conducted when South Africa was hit by the COVID-19 pandemic with concomitant learning losses, evidence shows that the Reading to Learn pedagogy improved the sampled Grade 10 learners’ reading skills. It was also highlighted that the department of education (DoE) should create conducive teaching and learning conditions through infrastructural development and provision of resources. , Thesis (MEd) -- Faculty of Education, Institute for the Study of Englishes in Africa, 2023
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Exploring outdoor mathematics learning for conceptual understanding through smartphones
- Authors: Pop, Vuyani Samuel
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/436477 , vital:73275
- Description: This study investigated how selected grade 11 mathematics learners used smartphones with the MathCityMap application to learn trigonometry outdoors for conceptual understanding. The aim of this research project was to explore outdoor mathematics learning for conceptual understanding using smartphones. This case study of grade 11 mathematics learners in Lejweleputswa District in the Free State Province, was informed by the Realistic Mathematics Education theory. The study is grounded within an interpretive paradigm and used the explanatory sequential mixed-method design. Forty-two grade 11 mathematics learners participated in the survey and from these 12 were purposively selected to participate in walking the mathematics trails and interviews. The findings revealed that, while the grade 11 mathematics learners acknowledged the significance and value of using smartphones for learning mathematics, they were prohibited from carrying or using smartphones on the school premises, as part of the school code of conduct. The preferred use of smartphones for learning mathematics was understandable, as the survey was conducted at a time when the COVID-19 pandemic and associated restrictions were still in place. The survey unearthed that among applications for learning mathematics, the MathCityMap application was not known by the learners who participated in the survey. Mathematics trails observations indicated that outdoor tasks were a source of mathematical concepts or formal mathematical knowledge, and enabled learners to reinvent mathematical ideas and concepts with adult guidance. Learners were able to make use of appropriate mathematical models and connections. The mathematics trails ignited robust discussions among learners, and prompted learners to draw from prior knowledge, and recognise and identify suitable mathematical models and shapes from the real-world objects. Learners were able to use multiple representations, make necessary mathematical links, and use their prior knowledge to enhance their trigonometry conceptual understanding. This study concluded that using smartphones with the MathCityMap application could enhance conceptual understanding of trigonometry. The implications for teachers are that learners should be exposed to outdoor mathematics learning using smartphones with the MathCityMap application to improve their conceptual understanding. It is hoped that the results of this study can be used by various stakeholders, who include, inter alia, mathematics subject advisors and teacher training institutions, to enhance learners’ conceptual understanding of mathematics. , Thesis (MEd) -- Faculty of Education, Secondary and Post School Education, 2024
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Genetic connectivity of the slinger Chrysoblephus puniceus among Marine Protected Areas and unprotected areas along the east coast of South Africa
- Authors: Ockhuis, Samantha Angelique Natasha
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435954 , vital:73215 , DOI 10.21504/10962/435954
- Description: Marine Protected Areas (MPAs) are advocated worldwide for the conservation of biodiversity and fisheries management, as well as for adaptation and resilience in the face of climate change. Their effectiveness has been noted through increases in abundances, biomass, sizes and diversity of species, as well as the recovery of overexploited fisheries. For MPAs to realise their full potential, these benefits need to expand beyond their boundaries through larval dispersal and/or adult spillover. Connectivity between MPAs is critical for planning and placement of MPAs, as this promotes the persistence of metapopulations, their recovery from disturbance, as well as productivity in marine ecosystems. The effectiveness of MPAs in conserving biodiversity along the east coast of South Africa has been established; however, limited evidence is available on whether they offer benefits beyond their boundaries, enhancing biodiversity and fisheries in adjacent areas. The slinger Chrysoblephus puniceus, an endemic southern African sparid, is a major component of the commercial linefishery in KwaZulu-Natal (KZN), South Africa and southern Mozambique, and is also caught in the recreational ski-boat fishery in these regions. The spawning of slinger occurs in shoals on offshore reefs from southern Mozambique to the north of KZN, and larvae are likely transported southwards, assisted by the southward-flowing Agulhas Current and promoted by a relatively long larval duration. Slinger are relatively resident, but occasional northward migrations have been observed. These life history characteristics suggested that slinger would be a suitable biological model to test connectivity along the east coast, and particularly connectivity between MPAs. The aim of this study was therefore to investigate connectivity of slinger between MPAs and the surrounding areas along the east coast of South Africa, using restriction-site-associated DNA (RAD) sequencing. This formed part of the larger CAPTOR project investigating east coast MPA connectivity across a range of taxa and habitat types. A temporal comparison of genetic diversity in slinger spanning two sampling events (2012 and 2018) revealed no substantial changes in genetic diversity, as well as a lack of genetic structure along the KZN coast. Similarly, no substantial changes in effective population size (Ne) were found between 2012 and 2018 for microsatellites and Single Nucleotide Polymorphisms (SNPs). However, subtle, albeit non-significant, differences were observed both spatially and over time in the microsatellite data, indicating some instability along the KZN coast. A lack of genetic structure based on RAD sequencing was observed between east coast MPAs and the surrounding areas. This implies high connectivity along the coast - not only are east coast MPAs connected, the surrounding areas are also connected, and there is replenishment between all areas via larval dispersal and/or adult spillover. Analyses of multidirectional gene flow between MPAs, together with known spatial spawning patterns and prior particle dispersal modelling, identified the Richards Bay area as a key source of recruits. However, parentage analysis – a direct method to estimate connectivity – failed to match any parent-offspring pairs in this study; successful parentage assignments are highly dependent on intensive sampling of potential parents and are seldom feasible in marine systems, as most populations have large effective population sizes. Estimates of intergenerational effective population size for slinger in this study are considered large - >2 000 and infinite based on adults and juveniles, respectively. Population genetics revealed close genetic similarities between slinger adult and juvenile slinger sites, emphasizing genetic connectivity and the lack of structure between sites observed before. This was the first study on South African sparids to use RAD sequencing to assess genetic connectivity between MPAs along the east coast of South Africa. Overall, results provide evidence that MPAs along the east coast of South Africa are connected, and can readily replenish or be replenished by other sites along the east coast of South Africa, whether they are within MPAs or not. So too are the areas surrounding MPAs interconnected, and slinger forms a homogenous single population on the east coast of South Africa. This notwithstanding, it is important that east coast MPAs, particularly those that host spawning shoals of slinger, are well managed in order that they continue to provide recruits to sustain the population and support sustainable fisheries. , Thesis (PhD) -- Faculty of Science, Ichthyology and Fisheries Science, 2024
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Graphene derivatives and electrocatalysts as composite electrodes for selective detection of catecholamine neurotransmitters
- Authors: Luhana, Charles Benjamin
- Date: 2024-04-05
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/435907 , vital:73211 , DOI 10.21504/10962/435907
- Description: In this thesis, we investigated the development of electrochemical sensing electrodes based on graphene derivatives and the electrocatalyst composites of metallophthalocyanines and metal oxides towards the selective and sensitive detection of catecholamine neurotransmitters (NTs). The graphene and its derivatives offer excellent electron conductivity and hence their use as base electrode materials. Metallophthalocyanines are N4-macrocyclic metal organic complexes that have structural modification flexible and 18-π electrons with excellent electrocatalytic properties. They can incorporate transition metal ions at the centre of the macrocycle ring, and this further enhances their electrocatalytic activity. Transition metal oxides are of interest as these also offer excellent redox properties and pH sensitivity. A pH sensitive electrochemical sensor based on aminated graphene quantum dots (AmGQDs) and cobalt tetra carboxyphenoxy phthalocyanine (CoTCPhOPc) covalent conjugates onto the pre-grafted isophthalic acid (IPA) gold electrode was fabricated. It displayed excellent analytical performance towards the detection of dopamine (DA), norepinephrine (NOR) and epinephrine (EP). The electrochemical sensor exhibited good ability to suppress the background current due to ascorbic acid (AA), a major interference in the detection catecholamine NTs. The carboxylic acid functional group of cobalt phthalocyanine induced the pH sensitivity of the thin film and electrostatic repulsion of the negatively charged ascorbate (AA-) anion at physiological pH. In addition, the electrode could screen-off biological molecules in the newborn calf serum as a representative of a real sample. An electrochemically reduced graphene oxide–based cobalt phthalocyanine polymer (polyCoTAPc) composite electrochemical sensor was fabricated on glassy carbon electrode, GCE-ERGO/polyCoTAPc. The GCE-ERGO/polyCoTAPc could detect dopamine and paracetamol simultaneously as co-existing analytes in buffer and synthetic urine samples. We observed, (i) very strong absorption of the materials, (ii) increase in the electrode surface area, (iii) excellent conductivity, and (iv) electrocatalytic activity of the ERGO/polyCoTAPc composite surface. Furthermore, a simple ultrasensitive electrochemical sensor based on nickel hydroxide thin film electrodeposited onto reduced graphene oxide-molybdenum disulfide (RGO/MoS2) composite resulted in the electrochemical sensor that can selectively and simultaneously detect ascorbic acid, dopamine, and uric acid. A distinct peak potential separation was observed with excellent electrocatalytic oxidation currents. The electrochemical sensors developed in this work exhibited high sensitivity, selectivity, stability, and low detection limits suitable for the detection and determination of catecholamine NTs. , Thesis (PhD) -- Faculty of Science, Chemistry, 2024
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