Attitudes and achievement in statistics: a meta-analytic and functional near-infrared spectroscopy approach
- Authors: Wagenaar, Emma Kate
- Date: 2024-04-04
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/435490 , vital:73162
- Description: Statistics anxiety describes the extensive worry and apprehension that students may experience when faced with statistics content as part of their university curriculums. Student’s perfunctory disposition towards statistics has been indicated to negatively affect performance outcomes in statistics courses. Two meta-analyses were conducted to investigate the relationship between statistics anxiety and achievement in statistics. The first meta-analysis was inclusive of 22 studies investigating the relationship attitudes towards statistics and achievement, whilst the second meta-analysis focused on the relationship, primary amongst Psychology students. Student’s attitudes towards statistics were measured using the Survey of Attitudes Towards Statistics (SATS), whilst achievement in statistics courses was quantified using different outcome measures. Finding from the meta-analysis were supplemented by cortical mapping of the neural correlates of statistical reasoning using functional near-infrared spectroscopy (fNIRS). Results from the meta-analysis indicated a small significant relationship between university students’ Affect, r = 0.28, Value, r = 0.22 and Difficulty, r = 0.18, and subsequent achievement in statistics courses. A medium significant relationship between Cognitive Competence, r = 0.31, and achievement was also noted. Findings from the second meta-analysis, indicated a medium, significant relationship between Affect, r = 0.32, and Cognitive Competence, r = 0.35, and achievement. Moreover, a small significant relationship was found between Value, r = 0.24, and Difficulty, r = 0.23, in relation to achievement in statistics courses. Case study analysis of the neural correlates of statistics reasoning revealed varied signal quality findings of cortical mapping of the neural correlates of statistics in the dorsolateral prefrontal cortex (DLPFC). Moreover, seed-based correlation analysis indicated cortical activation of the dorsolateral prefrontal cortex paired with diverse prefrontal regions. Recommendations from the study include improvements to the fNIRS research design and the inclusion of larger samples to investigate the cortical mapping of the DLPFC in relation to statistics reasoning and statistics anxiety. , Thesis (MA) -- Faculty of Humanities, Psychology, 2024
- Full Text:
- Date Issued: 2024-04-04
Performance evaluation of baseline-dependent window functions with several weighing functions
- Authors: Vanqa, Kamvulethu
- Date: 2024-04-04
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/435850 , vital:73206
- Description: Radio interferometric data volume is exponentially increasing with the potential to cause slow processing and data storage issues for radio observations recorded at high time and frequency resolutions. This necessitates that a sort of data compression is imposed. The conventional method to compress the data is averaging across time and frequency. However, this results in amplitude loss and source distortion at the edges of the field of view. To reduce amplitude loss and source distortion, baseline-dependent window functions (BDWFs) are proposed in theliterature. BDWFs are visibility data compression methods using window functions to retainthe signals within a field of interest (FoI) and to suppress signals outside this FoI. However,BDWFs are used with window functions as discussed in the signal processing field without any optimisation. This thesis evaluates the performance of BDWFs and then proposes to use machine learning with gradient descent to optimize the window functions employed in BDWFs. Results show that the convergence of the objective function is limited due to the band-limited nature of the window functions in the Fourier space. BDWFs performance is also investigated and discussed using several weighting schemes. Results show that there exists an optimal parameter tuning (not necessarily unique) that suggests an optimal combination of BDWFs and density sampling. With this, ∼ 4 % smearing is observed within the FoI, and ∼ 80 % source suppression is achieved outside the FoI using the MeerKAT telescope at 1.4 GHz, sampled at 1 s and 184.3 kHz then averaged with BDWFs to achieve a compression factor of 4 in time and 3 in frequency. , Thesis (MA) -- Faculty of Science, Mathematics, 2024
- Full Text:
- Date Issued: 2024-04-04
Analysing equity and ethical dimensions of water governance challenges in the lower section of the upper Vaal River catchment, Gauteng, South Africa
- Authors: Tavengwa, Noleen Shamiso
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424199 , vital:72132
- Description: Poor water governance practices have been identified as one of the root causes of water problems confronting the South African water sector. This is evident in the lower section of the Upper Vaal River Catchment, where ineffective implementation of the regulatory measures has resulted in multiple incidents of illegal discharge of effluent from municipal wastewater treatment works, industrial and mining activities. Pollution and deterioration of water quality is a major challenge in the catchment; the Vaal River is severely polluted beyond acceptable standards and impacts negatively on other water users who have legitimate rights to the water resources. Pollution not only affects human activities and use, but also has negative impacts on ecological health and functionality. Poor water governance practices raise ethical implications for the rights to water for both social and ecological components. Although many water governance challenges in South Africa have implications that border on values and ethics, the relationship between these concepts has hardly been explored. In order to contribute towards filling this gap, this study explores water governance challenges and their ethical implications, and then analyse the equity dimensions of key water challenges among institutional actors in the lower section of the Upper Vaal WMA, Gauteng. The study uses a qualitative research approach which involves several methods of data collection: document analysis, workshops, focus group discussions, key informant interviews and participant observation. The data collected were analysed using thematic analysis, and then applied an ethical framework to distil ethical implications of the identified water governance challenges. There are five water governance challenges that were identified, which are i) failure in the implementation of water legislation and regulations, ii) ineffective leadership and management, iii) cooperative governance and poor accountability, iv) decentralisation and ineffective participation, and v) finance, infrastructure, and technical capacity. The deterioration of water quality and pollution due to ineffective implementation of the regulatory system has ethical implications towards protection of the ecological system and sustainable management of the water resources for the present and future generation. Ineffective implementation of the regulatory measure also raises the issue of distributive equity between different water users and between current and future users. These implications are critical particularly when viewed from the perspective of systemic-relational ethical approach which posit that in social-ecological systems, all components ought to be treated with equal regards, and their inherent worth respected in order to maintain the unity of the SES. The idea of equal regards to the inherent worth of the component implies due respect, in ways that do not undermine the integrity of the entire system. The challenges identified in the system suggest that i) the right of the ecological system to water is undermined due to anthropogenic activities, which may in the long term undermine the functionality of the entire SES; ii) the right of the margined to access to water of the right quality is also undermined, and pollution costs is externalised. These are matters of ethics that thus deserved attention in policy and management considerations. The study analysed equity dimensions (distributive and procedural), targeting the key institutional water users (i.e., mines, industries, agriculture, municipalities, and the wastewater treatment works) in the lower section of the Upper Vaal River Catchment as equity candidates due to their activities that significantly impact the environment and the water resources. The cost of pollution caused by mining activities, industrial activities and the wastewater treatment works is externalised to other users who are not responsible for the pollution. In this regard study identified key drivers that raise concerns linked to distributive equity, which are ) pollution and water quality deterioration, ii) the legacies of mining activities, and iii) poor infrastructure maintenance, vandalism, and theft. Identifying these key drivers of distributive equity concerns is critical in ensuring that the water governance processes are designed in a way that stakeholders and actors reliant on water resources within the catchment have equitable and fair access without the effects of externalised costs from other actors. The identified water governance challenges in the catchment all borders on ethics, thus an ethical framework is crucial in tackling water related problems. The principles of ethics can be used as guidelines to decision-making process for the management and governance of water resources in South Africa. Therefore, implementing and incorporating principles of the systemic-relational ethics into policy making and water resources management will yield sustainable, efficient, and equitable use and management of water resources. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2023
- Full Text:
- Date Issued: 2023-10-13
Application of in vitro release testing (IVRT) to assess “sameness”/differences of topical clotrimazole formulations
- Authors: Wellington, Hannah Margaret Mary
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419599 , vital:71658
- Description: Embargoed. Possible release date early 2025 pending publications. , Thesis (MSC Pharm) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-10-13
Comparison of the metabolic physiology of exploited and unexploited populations of red roman (Chrysoblephus laticeps) along the south coast of South Africa
- Authors: Nabani, Xolani Prince
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424358 , vital:72146
- Description: Anthropogenic-induced climate change and exploitation pose threat to many marine fishes on which a vast majority of people around the world depend. Rapid changes in sea surface temperature have a direct impact on the physiology of ectothermic organisms such as fish, potentially resulting in changes to population distribution, abundance, and demographics. In the face of climate change, the impacts of increasing temperature variability on fish populations may be exacerbated by exploitation. Understanding how the resilience of exploited populations is affected by climate change is critical to predict how fishes will respond in the future. This study aimed to augment our knowledge on the impact of exploitation and thermal variability on fishes by comparing the thermal physiology of an exploited and unexploited population of the resident, reef-dwelling, Chrysoblephus laticeps. Twenty live fish were collected from the exploited, Cape St Francis and 18 fish from the unexploited, Goukamma Marine Protected Area and transported to the laboratory. The metabolic performance, in terms of standard metabolic rate (SMR), maximum metabolic rate (MMR) and aerobic scope (AS) of individual C. laticeps were estimated repeatedly at 10 ℃, 16 °C and 21 °C. Linear mixed effects models were used to examine the relationship between temperature, population, and metabolic rate and a ‘cvequality’ test analysis was used to compare the variance structure of the metabolic rate regression model for each population. Overall, the findings of this study show that Chrysoblephus laticeps from the unexploited population maintains a significantly higher aerobic scope (AS) across all temperature treatments (10, 16 and 21 ℃) when compared with those from the exploited population. In addition, the maximum metabolic rate (MMR) of individuals from the unexploited population was significantly higher than that of individuals from the exploited population, but there was no evidence to suggest that variability was significantly different between the populations. On the other hand, the individuals from an exploited population had a significantly higher standard metabolic rate (SMR) at high temperatures of 21 ℃, while the unexploited population had a low SMR at these high temperatures, but a high SMR at 10 ℃. Despite these differences there was no significant variation in the SMR between the two populations. The findings of this study confirm previous work on different exploited and unexploited populations of C. laticeps and together these findings suggest that hook and line exploitation lead to reduced physiological phenotypic diversity and reduced physiological performance in exploited fish populations. These findings emphasise the importance of incorporating the iii physiological information to develop viable fisheries management tools in the context of climate change. This study also highlights the effectiveness of MPAs in conserving highperformance physiological phenotypes to maintain phenotypic diversity in fish populations. Future research should aim to evaluate the efficacy of existing MPAs in preserving the physiological diversity of important hook and line fisheries species, while fisheries managers should consider augmenting their approaches through the incorporation of well-designed MPA’s to promote physiological diversity. This will be critical to advance the development of sustainable management practices, not only in a South African context but globally, where oceanic and coastal environmental conditions are expected to rapidly change in the future. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13
COVID19 and accountability in South Africa: legislation, ethics and disaster risk management
- Authors: Chapman, Emma Deidre
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419565 , vital:71655
- Description: Embargoed. Possible release in 2026 pending publication. , Thesis (MSC Pharm) -- Faculty of Pharmacy, 2023
- Full Text:
- Date Issued: 2023-10-13
Enhancement of the electrocatalytic activity of phthalocyanines through the reduction in symmetry and conjugation to detonation nanodiamonds
- Authors: Ncwane, Lunathi
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424541 , vital:72162
- Description: This thesis reports on the synthesis of novel phthalocynines tetrakis[(benzo[d]thiazol-2ylthio)phthalocyaninato]cobalt(II)chloride (complex 1) and tris(2-(ethylthio)benzo[d]thiazole)2-(phthalocyanine-9-ylthio)propionate cobalt(II) chloride (complex 2). The complexes are combined with DNDs via different techniques such as π-π stacking, covalent linkage and sequential modification on glassy carbon electrode. The synthesized MPcs and conjugates were characterized using UV-visible, mass, Fourier transform infrared, and Raman spectroscopies as well as transmission electron microscopy and dynamic light scattering. Combining MPcs with DNDs sought to improve electrooxidation of hydrazine. The electrochemical studies were conducted using cyclic voltammetry, chronocoloumetry, electrochemical impedance spectroscopy and chronoamperometry. Hydrazine was utilized as an analyte of interest, due to its mutagenic and carcinogenic effects. Glassy carbon electrodes (GCE) were modified using drop and dry method. The conjugation via covalent linkage proved to be the best way of enhancing electrocatalytic properties. Since it performed better in terms of limit of detection (0.33 μM), even though catalytic rate and sensitivity are not the highest. , Thesis (MSc) -- Faculty of Science, Chemistry, 2023
- Full Text:
- Date Issued: 2023-10-13
Enteric microbial responses to host hyperthermia in southern African insectivorous bats: a test of thermal co-adaptation
- Authors: Hunter, Amy Alison
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424391 , vital:72149
- Description: Embargoed. Expected release date 2025. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13
Exploring grade 8 teachers’ code-switching in teaching orthographic drawing in the Khomas Educational Region, Namibia
- Authors: Iita, Gabriel
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424041 , vital:72118
- Description: Studies in learner English proficiency in Namibia have shown that a considerable number of learners in primary and high schools have low proficiency. Naturally, this will be problematic for both learners and teachers who operate under a policy that dictates that from Grade 4 upwards, English is the medium of instruction in government schools. Literature has shown a general bias towards English as a medium of instruction from both the Namibian government and Namibian parents, despite the broader level of low English proficiency among learners. Research reviewed within this study has outlined the multiple benefits of code-switching for both learners and teachers. In fact, a recent study on the perceptions of code-switching in classrooms among Namibian learners indicated a positive attitude towards code-switching as a learning tool. Grade 8 Technical Drawing classes tend to be challenging due to the complexity and novelty of some of the concepts and terminologies used when teaching the subject. This makes it particularly difficult for learners whose first language is not English. Learners struggle to understand and make meaning of the concepts and objects used in Orthographic Drawing. Code-switching has been seen as a beneficial pedagogical tool. The study was therefore conducted to explore the Grade 8 teachers’ code-switching when teaching Orthographic Drawing in the Khomas educational region, Namibia. The study used the Matrix Language Frame Model by Myers-Scotton as the theoretical framework which focuses on two crucial language aspects of participating in code-switching and the matrix and embedded language, which guided this study. The qualitative approach employed a case study design which was used to gain first-hand experience in the Technical Drawing classrooms. Semi-structured interviews and an observation checklist were the research instruments that were used to generate data on the use of code-switching in Orthographic Drawing. Two schools, two Technical Drawing classes with 40 learners and two teachers in the Khomas region, Namibia were conveniently and purposively sampled. The data were analysed using coding, descriptive statistics and thematic data analysis. The primary and secondary results indicate that code-switching occurrence has constructive effects. Consequently, recommendations have been made on the effective use of code-switching along with other pedagogical tools based on the research insights into code-switching when teaching and learning Orthographic Drawing. , Thesis (MEd) -- Faculty of Humanities, Study of Englishes of Africa, 2023
- Full Text:
- Date Issued: 2023-10-13
Exploring how Grade 11 Chemistry teachers mediate learning of the topic redox reactions in their classrooms in Namibia
- Authors: Iindombo, Junilla Inamudhimbwa
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424030 , vital:72117
- Description: The Namibian Chemistry ordinary level syllabus requires learners to study the topic of redox reactions. This topic has proven to be one of the most difficult for Namibian learners as reflected by their poor responses to questions in the Grade 11 and 12 Namibian Senior Secondary Certificate ‘O’ examinations. Teaching abstract concepts such as redox reactions requires higher cognitive thinking skills and thus presents a challenge. Against this background, this study sought to explore how teachers mediate learning of redox reactions in their classrooms. The focus was on conceptual understanding through linking content to the context of the learners. The study was underpinned by an interpretivist paradigm, within which a qualitative case study approach was adopted. Two Grade 11 Chemistry teachers from the Ohangwena and Oshana regions in Namibia were the research participants. I used semi-structured interviews, lesson observations and stimulated recall interviews to collect data. I used Shulman’s Pedagogical Content Knowledge as a theoretical framework in this study and the data sets were analysed using the Topic-Specific Pedagogical Content Knowledge components. Qualitative data were analysed inductively-deductively. The study’s findings revealed that teachers used various mediation tools such as analogies and prior knowledge. The results further illuminated that teachers should develop strong subject content knowledge and pedagogical content knowledge to have the best strategies in place to mediate learning of this topic. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2023
- Full Text:
- Date Issued: 2023-10-13
Identification of novel Arf1 GTPase inhibitors for cancer target validation
- Authors: Mqwathi, Nomxolisi Vuyokasi
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424666 , vital:72173
- Description: The key regulators of both anterograde and retrograde vesicular traffic, adenosine diphosphate-ribosylation factors (Arfs), also coordinate various signalling pathways and regulate cellular processes required for cell survival and function. In addition to its role in mediating secretory trafficking in the Golgi apparatus, the involvement of Arf1 in signalling pathways that contribute to the formation and progression of cancer has become apparent, and the overexpression and deregulation of Arf1 activity has been associated with cancer cell invasion, proliferation and metastasis. As with other small GTPases, Arf1 must cycle back and forth between an inactive (GDP-bound) and active (GTP-bound) conformation to carry out its function. However, the cycle of Arf1 inactivation and activation is controlled by Arf GTPase activating proteins (Arf-GAPs) that stimulate Arf1 to hydrolyse the bound GTP to GDP and Arf guanine nucleotide exchange factors (Arf-GEFs) that facilitate GDP for GTP exchange on Arf1, respectively. The identification of Arf1 inhibitors that indirectly disrupt Arf1 function by blocking its interaction with Arf-GAPs or Arf-GEFs has generated interest in their use as possible anti-cancer agents. The suppression of Arf1 activation (by targeting Arf-GEFs) has been investigated as a potential cancer therapeutic target and resulted in inhibitor compounds that have micromolar-range activity against cancer cells and targets and promising results in mouse models, but experience problems with bioavailability when used in vivo. This motivates the search for novel Arf1 inhibitors for validation purposes to question whether Arf1 is a viable target for cancer therapy. The purpose of the study was to employ a recently developed colourimetric screening assay to identify inhibitors of Arf1 activation (Arf-GEF inhibitors) and deactivation (Arf-GAP inhibitors), with a focus on evaluating the potential of Arf1 deactivation as an entirely novel anti-cancer target. The proteins required for the assay (Arf1, Arf-GEF and -GAP domains and a reporter protein, GST-GGA3) were expressed in E. coli. and purified using affinity chromatography. The assay could detect the activation of Arf1 by the catalytic Sec7 domain of the three Arf-GEFs chosen for this study, but reproducibility was compromised by the occasional spontaneous activation of Arf1 in the absence of the Arf-GEFs. By contrast, the assay could reproducibly detect Arf1 deactivation by an Arf-GAP domain (Arf-GAP1GAP) and was subsequently used to screen a library of α-helix mimetics. Thirteen hit compounds with IC50 values ranging from 0.53 to 20.95 μM were found to inhibit Arf-GAP1GAP-mediated stimulation of GTP hydrolysis by Arf1-GTP in this assay format, however, they did not effectively suppress the proliferation of three tested cell lines (HeLa, MCF-7 and MCF-12A). Interestingly, the results obtained from fluorescence microscopy studies suggested that the compounds disrupt Golgi structure and Arf1 localisation, presumably by keeping Arf1 in its active conformation by blocking Arf-GAP1 function. This suggests that the compounds affect Arf1 function in cells, and may be used to explore the feasibility of targeting Arf1 deactivation for anti-cancer purposes in a wider range of cell lines and experiments. It has been reported that Arf-GAP1 inhibition is associated with the suppression of cell migration, and the potential of the compounds as metastasis inhibitors may also be explored. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
- Full Text:
- Date Issued: 2023-10-13
In-silico investigation of the effects of genetic mutations on the structural dynamics of thiopurine s-methyltransferase and their implications on the metabolism of 6-mercaptopurine
- Authors: Mwaniki, Rehema Mukami
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/432553 , vital:72880
- Description: Thiopurine S-methyltransferase (TPMT) is a cytosolic enzyme that catalyzes the S-methylation of aromatic and heterocyclic sulfhydryl compounds such as 6-mercaptopurine (6MP), 6-thioguanine (6TG) and azathioprine (AZA) which is first converted to 6MP through reduction by glutathione S- transferases (GST). The compounds, generally referred to as thiopurines, are immunosuppressants used to treat childhood acute lymphoblastic leukemia (ALL), autoimmune disorders and transplant rejection. Thiopurines are prodrugs which require metabolic activation to give thioguanine nucleotides that exert their cytotoxic effects by incorporation into DNA or inhibiting purine synthesis. The methylation reaction by TPMT utilizing S-adenosylmethionine (SAM) as the methyl donor prevents their conversion to these toxic compounds. The catalytic activity of TPMT in metabolising these compounds has been associated with occurrence of genetic variations. The variations that result to missense mutations cause amino-acid changes and in turn alter the polypeptide sequence of the protein. This could alter functionality and structural dynamics of the enzyme. This study sought to understand the underlying mechanism by which 7 specially selected mutations impede metabolic activity of the enzyme on 6-MP using in silico techniques. VAPOR and PredictSNP were used to predict the effects of single nucleotide polymorphisms (SNPs) on the stability and function of the enzyme. Of the 7 mutations, only H227Q was predicted to be functionally benign while the rest (L49S, L69V, A80P, R163H, R163C and R163P) were predicted to be deleterious or associated with disease. All the SNPs were predicted to destabilize the enzyme. Molecular dynamics (MD) simulations were preformed to mimic the behaviour of the apo, holo and drug-bound WT and mutant enzymes in vivo. This was followed by post-MD analysis to identify changes in the local and global motions of the protein in the presence of mutations and changes in intra-protein communication networks through contact map and centrality metrics calculations. RMSD and Rg analyses were performed to assess changes in global motions and compactness of the enzyme in the apo, holo and drug-bound states and in the presence of mutations. These revealed that binding of the ligand had a stabilizing effect on the WT enzyme evident from more steady trends from the analyses across trajectories in the holo and drug-bound enzymes compared to the apoenzyme. The occurrence of mutations had an effect on the global motions and compactness of the enzyme across the trajectories. Most mutations resulted in destabilized systems and less compact structures shown by unsteady RMSD and Rg across trajectories respectively. The drugbound systems appeared to be more stable in most of the systems meaning that the binding of 6MP stabilized the enzyme regardless of the presence of a mutation. RMSF analysis recorded local changes in residue flexibility due to the presence of mutations in all the systems. All the drug-bound mutant systems lost flexibility on the αAhelix which caps the active site. This could have an effect on drug binding and result to defective drug metabolism. The A80P mutation resulted to a more rigid structure from both global and local motions compared to the WT enzyme which could be associated with its nearly loss of function in vivo and in vitro. Dynamic cross correlation calculations were performed to assess how the atoms moved together. Correlated, anti-correlated and areas of no correlations were recorded in all the systems and in similar places when compared to each other. This meant that occurrence of mutations had no effect on how the atoms moved together. Contact map analysis showed that occurrence of mutations caused changes in interactions around the positions where the mutations occurred, which could have an effect on protein structural dynamics. The A80P substitution which occurred on the surface away from the binding site was identified as an allosteric mutation that resulted to changes in the catalytic site. Contact maps for the drug-cofactor complex in the mutant systems in comparison with the WT protein revealed changes that could suggest reorientation of the drug at the catalytic site. This could be an implication to altered drug metabolism. Eigenvector centrality (EC) and betweenness centrality (BC) for the most equilibrated portions of the trajectories were calculated for all the studied systems to identify residues connected to the most important residues and those that were spanned the most in shortest paths connecting other residues. Areas that scored highest in these metrics where mostly found in regions surrounding the catalytic site. Top 5% centrality hubs calculations showed loss of major hubs due to mutations with gaining of new ones. This means that mutations affected communication networks within the protein. The gained hubs were in areas close-by the lost ones which could have been an attempt of the protein to accommodate the mutations. Persistent top 5% BC hubs were identified at positions 90 and 151 while one persistent top 5% EC hub was identified at position 70. This positions play important roles in shaping the catalytic site and are in direct contact with the ligands. It was concluded that in silico techniques and analysis applied in this study revealed possible mechanisms in which genetic variations affected the structural dynamics of TMPT enzyme an affecte 6MP metabolism. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2023
- Full Text:
- Date Issued: 2023-10-13
International students’ experiences of othering in tertiary education in South Africa: an exploratory study
- Authors: Lobakeng, Tsholofelo
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424986 , vital:72199
- Description: Despite rising cases of xenophobia in South Africa, international students remain committed to enrolling in its universities. Surprisingly, there is limited research looking into xenophobia in tertiary institutions. Therefore, the present study aimed to contribute to the scarcity of knowledge on the experiences of international students in South Africa. Thus, the study explored experiences of Othering among international students in tertiary education in South Africa and how they make sense of these experiences. Purposive and snowballing sampling techniques were employed to recruit international students (N=5) from Botswana, China, Zambia, and Zimbabwe. Data was collected through semi-structured, face-to-face online interviews. Participants reported experiencing a variety of non-violent forms of Othering, such as feeling excluded due to the intentional use of local languages in both classroom and social settings; being rejected by local students who refused to work with them; and being accused of stealing opportunities from local students. At an institutional level, participants reported systemic Othering rooted in unsupportive policies and practices that led to a negative and oppressive environment. The findings support previous research studies that purport the Othering of international students in higher education in South Africa mainly manifests through non-violent and covert forms. Moreover, participants attributed Othering of immigrants to racism, a perceived lack of exposure to diversity among locals, perceived lack of compassion for immigrants, and the tendency to scapegoat immigrants for the lack of employment opportunities in the country. The findings underscore the intricate nature of Othering and the need for further research to gain a greater understanding of this complex phenomenon. Furthermore, the findings highlight the importance of implementing effective strategies of inclusion and integration of international students at these institutions of higher learning. , Thesis (MA) -- Faculty of Humanities, Psychology, 2023
- Full Text:
- Date Issued: 2023-10-13
Investigation into methods of recovering campylobacter spp. from river water samples
- Authors: Ngoni, Nandipha
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424177 , vital:72130
- Description: Campylobacter species are slender, gram-negative, rod-shaped, spiral- or curved-shaped with single or pairs of flagella. They are the leading cause of diarrheal disease globally, consumption of and contact with water contaminated by faeces is a major risk factor for transmission of these organisms to humans. Rivers used for recreation and domestic and agricultural activities represent all the risk factors for Campylobacter spp. pollution and human exposure. Campylobacter spp. However, effective methods to recover Campylobacter spp. from river water samples are lacking, indicating the need for the development of more efficient methods of detection and isolation of these organisms from environmental water samples. Campylobacter detection in a water sample is critical to ascertain potential risks to humans. The aim of this study was to determine a suitable method for the detection of Campylobacter spp. from river water samples and the objectives were to (i) to evaluate the performance of different methods used for the recovery of Campylobacter spp. from environmental water samples based on Campylobacter colony count and PCR identification results, (ii) isolate and enumerate Campylobacter cells from river water samples, and (iii) identify Campylobacter spp. in river water samples. The Bloukrans River was chosen for this study because it is suspected to be contaminated by faecal inputs from nearby informal settlements without adequate sanitation, as well as untreated/insufficiently treated effluents from nearby wastewater treatment plants. First, the physicochemical quality of the river water and the presence of faecal contamination were assessed to confirm suitability for Campylobacter spp. survival and presence. Then different approaches to sample, concentrate and recover Campylobacter spp. from river water samples were assessed. The different methods assessed were (i) direct enrichment of water samples without prior concentration, (ii) prior concentration of water samples by centrifugation followed by membrane filtration of supernatant, and after that, pooling the residue and pellet together for enrichment, (iii) sampling by the Moore Swab technique. For all three methods, enrichment in Bolton broth supplemented with Bolton antibiotics was conducted. This was followed by plating on modified cefoperazone charcoal deoxycholate agar (mCCDA) and incubation under a microaerophilic atmosphere at 42°C for 48 h. Colony morphology, Gram staining and polymerase chain reaction (PCR) were used to identify and characterize the microorganisms. The growth of blue colonies on the mFc agar surface confirmed presence and faecal pollution of the Bloukrans River. The physicochemical properties, based on the range of pH measured at different sites of the river (between acidic 3.45 to 6.42 and alkaline 7.2 to 8.74) indicate that Campylobacter spp. can thrive in the river. Based on the results from enumeration and sequencing of colonies recovered by each method, it was discovered that the most suitable method to recover Campylobacter spp. from river water samples is by prior centrifugation (14,000 × g for 30 minutes) followed by membrane filtration of the supernatant, and subsequent pooling of the residue and pellet. The pooled residue and pellet might have increased Campylobacter spp. concentrations aiding more growth during the enrichment of Campylobacter spp. from the river water samples. Results from enumerating Campylobacter spp. cells from river water samples indicate that Campylobacter spp. are present in Bloukrans River. The sequence obtained from the PCR product indicates that the species found were Campylobacter jejuni (96% homology as evaluated by BLAST). This study provided a procedure effective for obtaining a satisfactory quantitative recovery of Campylobacter spp. from environmental waters, a critical need for quantitative microbial risk assessment studies. , Thesis (MSc) -- Faculty of Science, Institute for Water Research, 2023
- Full Text:
- Date Issued: 2023-10-13
Investigation of brewery waste grains and microbial fuel cells as value-additive technologies improving solvent production yields in Clostridium acetobutylicum (ATCC 824) fermentation
- Authors: Du Toit, Ryan Guillaume
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424643 , vital:72171
- Description: The production of the solvent compounds acetone, ethanol and butanol through fermentation of organic feedstocks using Clostridia species could be a promising route for biofuel production. However, the cost of raw materials, low yields and the complexity of anaerobic fermentation continue to hinder this means of generating these compounds. The research presented in this Thesis investigated low-cost interventions that could decrease the costs of production and to direct the synthesis of fuel compounds using microbial fuel cells. Low-cost anaerobic chambers were designed and constructed for the propagation and manipulation of Clostridium acetobutylicum, selected as a low-risk microbial catalyst. Fermentation was monitored using in situ pH measurements and a combination of turbidity measurements, nutrient assays (especially total carbohydrates) and HPLC-RI detection as a means of monitoring the consumption of nutrients (glucose), production of precursor compounds (butyric acid) and the formation of solvent molecules (acetone/ethanol and butanol) during fermentation by this organism. Brewer’s spent grains were tested as a sustainable and low-cost feedstock for solvent production, comparing the effects of sterilising before fermentation, or allowing resident microflora to remain during Clostridium-catalysed solvent production. Sterilised spent grains significantly improved the production of solvent molecules (e.g. 12.97 ± 0.38 g/L of butanol yielded, compared to 0.40 ± 0.33 g/L for defined media sampled during the solventogenic phase); compared to these, the use of non-sterilised brewer’s grain decreased both the reproducibility and yields of fermentation (8.66 ± 1.6 g/L of butanol). Microbial fuel cells were studied as a possible means of altering electron transfer to/from electrode-attached Clostridia to control the metabolic shift in bacteria from acidogenesis to solventogenesis. The base line MFC (11.00 ± 4.69 g/L) fermentation experiment did produce higher acetone/ethanol than the baseline batch experiment MB (5.47 ± 4.48 g/L), indicating an improvement to solvent production in C. acetobutylicum (ATCC 824) in a MFC fermentation. In this study, MFC-1 demonstrated remarkable superiority over MB in terms of butyric acid production, yielding significantly higher concentrations while also improving acetone and ethanol production. However, the enhanced butyric acid production did not correspond to significantly increased butanol yields when compared to batch fermentation of chemically defined media. These findings highlight the potential of MFC-1 as an efficient approach for enhancing the fermentative production of valuable compounds, with a particular focus on butyric acid and acetone/ethanol. , Thesis (MSc) -- Faculty of Science, Biotechnology Innovation Centre, 2023
- Full Text:
- Date Issued: 2023-10-13
Phylogeography of two small owl species in South Africa: population genetics and phenotypic variation in the African Barred Owlet (Glaucidium capense) and the African Scops Owl (Otus senegalensis)
- Authors: Balmer, Jonathan Peter
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424369 , vital:72147
- Description: Embargoed. Expected release date in 2025. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13
Relating vegetation distribution to cycles of erosion and deposition in the Kromme River wetlands
- Authors: Jarvis, Samuel Cameron
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424582 , vital:72166
- Description: The role of geomorphic disturbance has been increasingly recognized as fundamental in the creation and functioning of wetlands. This is true of the Kromme River wetland which has been formed through repeated cycles of erosion and deposition. However, the response – and influence – of wetland plants to these sorts of disturbance has not been investigated. This study sought to fill this knowledge gap by classifying vegetation communities over a range of hydrological and geomorphic disturbance regimes that have happened over the last few decades, and relating those vegetation communities to environmental factors. The study identified seven vegetation communities based on their species composition and abundance, which were related to geomorphic disturbance events. A conceptual model that accounts for vegetation distribution in the Kromme wetland was developed. Soil saturation was the most important factor explaining vegetation community distribution, which, in turn, is influenced by cycles of erosion and deposition. Following an erosional event on the valley floor, Prionium serratum dominated wetland is converted to a number of other vegetation communities. On the floodplain surface adjacent to the eroded gully, the Prionium serratum dominated wetland is transformed over time to Cynodon dactylon and Sporobolus fimbriatus communities. Prionium serratum clumps immediately adjacent to the recently incised gullies are able to persist, having sufficient access to water. Within the newly formed gullies, Juncus lomatophyllus colonizes the gully beds flooded to a shallow depth, Miscanthus capensis colonizes the gully bars and Setaria incrassata colonizes the exposed gully banks. Localised depositional features close to the thalweg in the gully are colonized by Prionium serratum seedlings and vegetative propagules. These plants represent the regenerating phase of Prionium serratum wetland, which also colonizes depositional floodouts downstream of the newly-formed gully. The Stenotaphrum secundatum community dominates drier, more elevated areas of the floodout. Over time, as the gully fills, Prionium serratum expands beyond the gully onto the valley floor, to replace the floodplain communities Cynodon dactylon and Sporobolus fimbriatus. Over time, Prionium serratum is thought to colonize the valley floor as the gully fills, stabilising it and promoting diffuse flow. Many restoration efforts in damaged palmiet wetlands have been focused on the preservation of intact palmiet communities upstream of erosional headcuts, with limited understanding of vegetation dynamics associated with the cut-and-fill cycles that naturally occur in these wetlands. Understanding the regeneration of Prionium serratum following erosional events is thus important for wetland restoration, as it should focus more attention on promoting palmiet restoration on depositional floodouts downstream of eroded gullies. A secondary aim of this study was to explore the possibility of mapping palmiet communities in Kromme River wetland using remote sensing techniques. Using a combination of ground-truthed data from this and previous studies in the Kromme River wetland, together with raster layers derived from a LiDAR survey, an overlay analysis was developed to effectively map the distribution of the Prionium serratum dominated community. The overlay was created using a machine learning library in RStudios known as Rpart. The results found that the model were 91% effective in classifying the distribution of the Prionium serratum community. A secondary finding was that the inclusion of a Relative Elevation Model in the overlay analysis allowed for the identification of Prionium serratum communities vulnerable to degradation following previous geomorphic disturbance events and those Prionium serratum communities that are likely to persist following a geomorphic disturbance event. , Thesis (MSc) -- Faculty of Science, Geography, 2023
- Full Text:
- Date Issued: 2023-10-13
Spatial analysis of littoral and demersal fish assemblages within the Knysna Estuary system
- Authors: Meiklejohn, Andrew Keith
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424334 , vital:72144
- Description: The Knysna Estuary is a unique system as it is the only “estuarine bay” system in the warm-temperate region of South Africa and is the largest estuary system on the southern coastline of South Africa. The Knysna Estuary has been identified as the estuary with the highest conversation priority in South Africa. The volume of research undertaken on the Knysna Estuary has led to it being rated “excellent” in terms of research productivity. However, despite this, surprisingly little work has been undertaken and published around the dynamics of fish assemblages occurring in the system, with little to no research assessing the demersal fish assemblage. The last widespread fish sampling effort that has been published was conducted in 1994, highlighting the need for an updated fish assessment with a focused sampling effort targeting both the littoral and demersal fish populations. The identification of key habitats for estuarine fish assemblages is essential for addressing estuarine conservation needs. Despite the importance of spatial data in addressing conservation planning, few estuarine studies have used spatial analyses in Geographic Information Systems (GIS) to identify conservation priority areas. Such information is critical for effective estuarine management plans. The aim of this project was to identify juvenile fish density hotspots to inform future systematic conservation planning. This study made use of two methods of sampling, seine netting to target the littoral fish assemblage and beam trawling to target demersal fish species. Two dedicated sampling trips for each sampling method were undertaken in June 2021 and March 2022 for Seine net sampling and November 2021 and March 2022 for Beam trawl sampling. Fish were identified to species level, measured (mm TL) and categorised into life history stages (i.e. settlement stage, juvenile and adult) and thereafter assigned into their various estuarine association guilds. A total of 47 species were recorded, with 42 species were caught in the seine net sampling and 24 species in the beam trawl sampling. The results from this study showed the vast extent of marine dominance in the Knysna Estuary, with marine estuarine-opportunist (MEO) species dominating catches (richness) from both sampling methods. The spatial analysis highlighted the importance of the lower “marine bay” region of the system, with the majority of estuarine guilds showing a high abundance in this region. Key fishery species and dominant fish species were identified during this study, the dominant species during the sampling effort were identified as ecologically important fish species and were dominated by adult specimens. The key fishery species sampled during this study were dominated by juvenile specimens. This highlights the role of the Knysna Estuary as a nursery area for juvenile fishery species and the contribution of the estuary to the estuarine and adjacent coastal fisheries. Key hotspots were identified for fishery species, these being the “Ashmead Channel” in the marine bay region and the “Belvidere” section of the lagoon region. Ashmead channel is sheltered backwater area while the Belvidere section is some distance from the main river channel, reducing the anthropogenic impact on these areas. The low anthropogenic utilization of these areas along with weaker water current in these regions was linked to the usage of these region by key fishery species. These areas were highlighted as important conservation hotspots with both currently not adequately protected under the current habitat sensitivity management model. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2023
- Full Text:
- Date Issued: 2023-10-13
Stimulating continuous professional development and teacher leadership in a rural Namibian school: a participatory action research
- Authors: Mario, Kangende Mebin
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424075 , vital:72121
- Description: Namibia values democratic and quality education. One way to improve quality education is by allowing teachers autonomy and offering continuous professional development (CPD) to teachers. Historically, the CPD programmes on offer in Namibia were centralised and generic, using a ‘one-size-fits-all’ approach offered as mini workshops to train teachers. In 2012, a decentralised method of school-based CPD program was initiated in schools, to give opportunities to schools to identify, plan, implement and evaluate their own professional needs. However, a recent study indicated that these initiatives have failed due to poor leadership, a lack of training and support as well as limited knowledge of principals in running CPD initiatives. Against this backdrop, my study aimed at engaging in a participatory action research process with teachers and SMT members in a rural combined school in the Kavango West region to stimulate the failed school-based CPD program and develop teacher leadership. My study therefore aligned with the international recommendations that school-based CPD be built around the notions of distributed leadership and teacher leadership (Smulyan, 2016; Hunzicker, 2018). The three-step model of change and action research developed by Kurt Lewin served as the underpinning theory for this study. The study was situated within a critical paradigm and driven by the question: “Does the involvement in participatory action research process stimulate a school-based CPD programme and develop teacher leadership?” The study involved two phases. The contextual profiling stage generated data through the analysis of documents, focus group interviews, and observation. Phase 2 engaged the participant in participatory action research to stimulate school-based CPD and develop teacher leadership. Thematic analysis supported by both inductive and deductive methods was used to analyse the data. The findings from phase one indicated that CPD was interpreted differently by the participants and confirmed that there was no CPD program in the school. Using Grant's (2017) model of teacher leadership, the findings further revealed that although teacher leadership was practised in all four zones, it was strongest in the classroom and initiated through delegated practices. Using Angelle and Dehart (2010), constraining forces included negative teachers’ attitudes, limited knowledge, skills, and confidence as well as a school culture of distrust. Phase 2 revealed that participatory action research can be a useful stimulus for school-based CPD. A tangible output from the PAR sessions was a template for the internal policy for school-based continuous teacher development. In addition, the findings from the sessions indicated the significance of supportive leadership to ensure the efficacy of school-based CPD and teacher leadership. , Thesis (MEd) -- Faculty of Education, Primary and Early Childhood Education, 2023
- Full Text:
- Date Issued: 2023-10-13
The activity and foraging patterns of the western rock elephant shrew (Elephantulus rupestris)
- Authors: Jackson, Emily Anne
- Date: 2023-10-13
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/424402 , vital:72150
- Description: The increase, and prolonged periods, of high ambient temperatures are cause for concern for small mammals living in arid areas of Southern Africa. In this study, I aimed to determine the effect of high environmental temperatures on the activity, body temperature maintenance and foraging behaviour in a population of Western rock elephant shrew, Elephantulus rupestris, in the Eastern Cape, South Africa. I found that E. rupestris maintained stable body temperatures (Tb = 37.31 °C ± 0.64) over a range of environmental temperatures (Tair = 5° to 33.9 °C), indicating their ability to remain normothermic during the heat of the day. Under cool, mild and hot air temperatures, E. rupestris were predominantly active in the morning and night, being the least active during midday. This shift in activity time, known as polyphasic activity, is common amongst Macroscelidea species and is a mechanism for escaping thermal extremes. To determine the effect of temperature on foraging behaviour, I ran giving-up density (GUD) experiments on E. rupestris under a range of environmental conditions. GUD experiments yielded no conclusive results as animals did not show a significant preference for foraging under certain thermal conditions, and rather foraged under a variety of air temperatures. Overall, E. rupestris showed risk adverse behaviour, trading-off thermoregulation with foraging and activity for self-preservation during hot periods of the day. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2023
- Full Text:
- Date Issued: 2023-10-13