The depositional history and evaluation of two late quaternary, diamondiferous pocket beaches, south-western Namibia
- Authors: Milad, Micael George
- Date: 2004-03
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/420934 , vital:71795
- Description: The two Late Quaternary, diamondiferous pocket beach deposits studied here are situated along a 10 km stretch of the storm-dominated, Atlantic coastline of the Sperrgebiet, south-western Namibia. The pocket beaches are approximately 130 km north of the Orange River mouth, which is widely accepted as a long-lived point source for diamonds sourced from the interior of southern Africa. A total of fourteen pocket beach deposits were recently evaluated in this area, but only two of these, namely Site 2 (to the south) and Site 3 (to the north), are considered here. The main diamondbearing horizons are beach gravels, which occur within, and form part of, the pocket beach sequences. The beach gravels are mostly blanketed by sand overburden, meaning that exposures available for study were limited, and much reliance was placed on borehole logging and observations of evaluation sample tailings. The main aims are to unravel the depositional history of the pocket beach sequences, identify the controls on diamond mineralisation in the beach gravels, and critically examine two different methods of estimating average diamond size for the deposits. In pursuit of these aims, sedimentological characteristics of the unconsolidated pocket beach deposits were recorded using small diameter drill holes, hydraulic grab bulk samples, trench exposures and surface outcrops. The surface geology, geomorphology and modern wave patterns were mapped using high-resolution, Airborne Laser Survey imagery coupled with extensive field checking. Three-dimensional geological modeling software was used to gain insight into the subsurface morphology of the deposits. Fossil shell samples were used to aid interpretation of ancient depositional environments and to date parts of the pocket beach sequences. Variations in diamond concentration and the size of diamonds were recorded using bulk samples, some of which were taken from a trench, but most of which were excavated using a hydraulic grab tool called the GB50. Finally, by using diamond size data from Site 3, sample data from diamondiferous beach gravels to the south of the study area and sample campaign simulations, two alternative methods of evaluating average diamond size in marine gravel deposits were appraised.The pocket beach sequences occur within north-south trending valleys of a major deflation basin and are separated from one another by rocky headlands. The ridge-and-valley topography of the deflation basin has resulted from differential erosion of Late Proterozoic basement rock units, alternating layers of which differ greatly in their resistance to the long-lived, local denudationalprocesses. On the basis of the stratigraphic information collected from the unconsolidated pocket beach valley fills, interpreted within the context of global, Late Pleistocene sea level records, the following depositional history is deduced : a) Deposition of sheetflood gravels by ephemeral streams, activated during a regressive phase. b) Transgression, culminating in the deposition of a gravel beach, representing a sea level highstand of +4 metres above mean sea level (mamsl) at between 120 000 and 130 000 BP. c)A regressive phase, resulting in deflation of former valley fills to the bedrock valley floor and accompanied by re-activation of ephemeral stream activity to form sheetflood deposits; this represents a protracted period of subaerial exposure of the +4 m gravel beach deposit. d) Deposition of a great volume of sediment in the valleys during the latter stages of the transgression from the Last Glacial Maximum (LGM). The sequence generated during this phase, which started at ca. 9 000 BP, contains : i) pan/coastal sabkha sediments, ii) shallow, sheltered bay sediments, iii) back-barrier lagoonal sediments, iv) a gravel beach deposit representing a sea level stillstand at -5 mamsl, laid down between 7 600 and 5 600 BP, v) another gravel beach deposit representing the well-known Middle Holocene sea level highstand at +2 to +3 mamsl, laid down at ca. 5 000 BP, and which terminated the transgression from the LGM. e) A minor regression to the current sea level, accompanied by progradation of the shoreline to its current position. This progradational marine unit consists almost entirely of sand and grit, reflecting the lack of gravel supply to this part of the coastline in the most recent past. f) Deposition of modern coastal dunes, which cap the pocket beach sequence and are the youngest sediments in the study area. Using trench and hydraulic grab evaluation sample results, in combination with analysis of wave patterns and field observations, the following local controls on the density distribution (ie. concentration) and size distribution of diamonds in the gravel beach deposits (+4, -5 and +2 to +3 mamsl stands) are recognised: a) Gravel beach depositional processes, which are responsible for clast sorting on the beach, have influenced the density and size distribution of diamonds. The infill zone, or beach toe, favours maximum diamond concentration while diamond size decreases from the imbricate zone (intertidal) to the infill zone (subtidal). b) Wave energy is identified as the dominant local control on diamond size distribution, but has also influenced diamond concentration to a limited degree. Larger diamonds are intimately associated with coarser beach gravels, both of which are a reflection of increased wave energy. Higher concentrations of diamonds are sometimes associated with zones of coarser gravel and therefore greater wave energy. c) The time of deposition of the host gravel beach is seen to be the dominant controlling factor with respect to diamond concentration. This is seen as evidence of significant temporal variation in the availability of diamonds in the littoral evironment. A significant reduction (20%) in average diamond size from Site 2 to Site 3, over a distance of only 6 km, is evident. The following were identified as reasons for this reduction in diamond size : a) Longshore sorting processes, of which the long-lived northerly littoral drift is a key part, are known to have played a role in the diminution of diamond size northwards from the Orange River mouth point source. However, it is believed that this can only partly account for the observed 20% reduction in diamond size. b) Input of sediment and smaller diamonds at Site 3, reworked out of an older, Eocene-aged marine succession in the hinterland, is recognised as a possible additional reason for the large reduction in diamond size from Site 2 to Site 3. It is also speculated that the large size of the pocket beach at Site 3, relative to Site 2, may have resulted in lower average wave energy at Site 3, with consequent reduced average diamond size. Diamond size in the beach gravels of Site 3, as well as in beach gravels elsewhere in the Sperrgebiet, is seen to be lognormally-distributed within geologically homogeneous zones. In theory, lognormal mean estimators represent the best method of estimating average diamond size in such cases, whereas the arithmetic mean estimator has the tendency to overestimate when large outlier values occur. Lognormal mean estimators have the added benefit of providing for the calculation of confidence limits, which are becoming increasingly more important as financial lending institutions insist on better quantification of the risk involved in resource estimates. Sample campaign simulations demonstrate, for the kinds of diamond size-frequency distributions typical of beach gravel deposits at Site 3, that there is no significant improvement in the accuracy of average diamond size estimates when lognormal mean estimators are used instead of the arithmetic mean estimator. This is because the variance (a ) of the diamond populations is low, and large outlier values are extremely unlikely to occur. However, simulation of a diamond population with high variance, drawn from a sample of beach gravels near the Orange River mouth, shows that lognormal estimators produce significantly more accurate results when a is large. Since individual diamond weights were not recorded during evaluation sampling of Site 3, numerical solution of lognormal estimators is not possible, and these would need to be solved using a less accurate graphical method. It is therefore recommended that individual diamond weights are recorded in future sampling campaigns, allowing for the use of lognormal mean estimators, and the calculation of confidence limits for average diamond size estimates. , Thesis (MSc) -- Science, Geology, 2004
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- Date Issued: 2004-03
Exploring pre-service teachers’ reflective practice in the context of video-based lesson analysis
- Authors: Chikiwa, Samukeliso
- Date: 2020-04-30
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/355357 , vital:64492
- Description: This study explored the development of reflective practice in foundation phase pre-service teachers in the context of video-based lesson analysis at a university in South Africa. The study was conducted in the field of mathematics education, responding to the urgent need to equip pre-service South African teachers with the knowledge and skills for effective mathematics teaching. The research is foregrounded by the continuing poor performance of South African learners in mathematics at all levels of education in the country, which has been linked to the inadequate knowledge and skills of mathematics teachers. Pre-service teacher education is putting considerable effort into improving the preparation of mathematics teachers and developing their ability to reflect on their teaching practice is one of the strategies being employed for this purpose. Research has demonstrated the importance of reflective practice (RP) in both developing and extending teachers’ mathematical knowledge for teaching. This study therefore contributes to current research that supports the development of RP as a professional skill for promoting the acquisition of knowledge for teaching in pre-service teacher education. The study adopted a qualitative case study approach with two phases of data collection. In Phase 1 I collected and analysed three sets of 19 pre-service teachers’ written reflections to establish the nature of the reflections that they developed when analysing video-recorded mathematics lessons of experienced teachers’ practice. Phase 2 was conducted with four PSTs who reflected on video-recorded mathematics lessons of their own practice, and similarly sought to investigate the nature of the reflections they developed when reflecting on practice. The four PSTs wrote one set of reflections on their own lessons, went through three sessions of facilitator-guided reflections, then wrote another set of reflections to establish if the support provided in small group facilitator-guided sessions improved their reflections. Iterative content analysis was employed to analyse the PSTs’ written reflections, using an analytic tool that I developed for this purpose through merging Lee’s (2007) and Muir and Beswick’s (2007) levels of reflection frameworks. My model had four levels of reflection: description, explanation, suggestion and reflectivity. The names of each of the levels connect to the key indicator for that level. PSTs’ written reflections were coded and analysed according to these levels. The study found that PSTs’ initial reflections were mostly description of general classroom events with little reflection at the levels of explanation and suggestion, and an absence of reflectivity. Most reflections focused on general events in the lesson rather than mathematical events, even though the six lens framework they were given to guide their reflections prompted them to steer their attention towards mathematical events. The second and third sets of reflections, although mostly still at level 1, showed some shifts towards explanation and suggestion, although an increased focus on mathematical events though reflectivity was still largely absent. No PST reached the fourth level of reflectivity in Phase 1. However, in Phase 2, the PSTs’ reflections after the three small group facilitator-guided sessions included some evidence of reflectivity. The findings suggest the need for pre-service teacher educators to make a concerted effort to teach PSTs what reflection is and how to reflect on their practice. The findings also showed the need for small group facilitator-guided support in the development of PSTs’ reflective practice. , Thesis (PhD) -- Faculty of Education, Education, 2020
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- Date Issued: 2020-04-30
Academic distress & disordered eating in students
- Authors: Du Toit, Mae
- Date: 2021-10-29
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/192626 , vital:45244
- Description: University students are at risk for reduced mental wellbeing, particularly during the Covid-19 pandemic, and among the most common problems experienced are academic distress and eating concerns. Through a stress-coping model lens, a link between academic distress and disordered eating in student populations appears possible but has not previously been explored. The present study examines this relationship in a South African undergraduate sample. Data were collected during the Covid-19 pandemic using a cross-sectional, correlational survey design and the Counseling Center Assessment of Psychological Symptoms (CCAPS). The results of a multiple regression analysis indicate that academic distress most strongly predicts eating concerns, followed by the demographic variables of female gender and black racial identification. This novel finding suggests that academic institutions should consider the broader academic environment as point of intervention for the prevention and treatment of disordered eating in students. , Thesis (MA) -- Faculty of Humanities, Psychology, 2021
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- Date Issued: 2021-10-29
Synthesis and evaluation of the medicinal potential of novel 4-hydroxycoumarin derivatives
- Authors: Manyeruke, Meloddy Hlatini
- Date: 2022-04-08
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/164458 , vital:41120 , doi:10.21504/10962/164458
- Description: This research has focused on the synthesis and biological evaluation of a broad range of compounds characterised by the presence of the pharmacologically significant 4-hydroxycoumalin scaffold. The compounds were designed to contain additional pharmachophoric centres to enhance bioactivity and generate lead compounds with dualaction potential. The use of 4-hydroxycoumarin as the primary synthon enabled access to various series of 4-hydroxycoumarin conjugates, the reactive 3-position on the 4-hydroxycoumarin moiety being exploited for regioselective construction of the targeted compounds in several steps. Some of the reactants required in the construction of these compounds were specially synthesised and included propargyloxy benzaldehydes, benzyloxy benzaldehydes and 2,3-dihydroxysuccino-dihydride. Overall, eight different families of novel compounds were accessed, comprising conjugates of 4-hydroxycoumarin with bisethylidenesuccinohyrazide, trifluoroacetamide, amino, benzyloxyphenyl-iminoethyl, benzylidenehyrazinyl-thiazoyl, benzylidenehydrazonoethyl, propargyloxybenzylidenehydrazonoethyl and phenylacryloyl moieties using protocols that required minimal work-up and purification. The eighty novel compounds synthesised in the study were fully characterised using HMRS and advanced NMR techniques. Cytotoxicity, HIV-1 IN and PR inhibitory, and antitrypanosomal, antimalarial and anti-Mtb assays were conducted on the synthesised coumarin derivatives. Several compounds exhibited activity against HIV-1 IN, the most potent being a bis-ethylidenesuccinohyrazide with an IC50 value of 3.5 μM. Various compounds exhibited anti-malarial activity (% pLDH viability in the range 62-77%), anti-trypanosomal activity (the most potent with an IC50 = 0.9 μM against T.b. brucei) and a measure of anti-Mtb activity. Apart from two chalconyl derivatives, none of the synthesised compounds exhibited significant cytotoxicity. Conflicting results were obtained from the in silico docking studies; in some cases supporting the observed in vitro assay data while, in others, exhibiting no correlation. , Thesis (PhD) -- Faculty of Science, Chemistry, 2020
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- Date Issued: 2022-04-08
A case study on responsible leadership in a renewable energy organisation in the Eastern Cape
- Authors: Mdingi, Chulumanco
- Date: 2022-06
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/419101 , vital:71616
- Description: This research was a case study of responsible leadership in a renewable energy organisation in the Eastern Cape. The study aimed to understand and describe how a renewable energy organisation applies responsible leadership to build trust. The four objectives of the study were namely to: (1) describe how the organisation interacts with its stakeholders to build trust; (2) understand how the members of the organisation demonstrate the characteristics of responsible leadership; (3) understand how different stakeholders perceive and experience the interaction of the company with established stakeholders; (4) make recommendations that a renewable energy organisation can exercise the characteristics of responsible leadership to develop its stakeholder engagement framework. In the study the stakeholder theory was applied as the theoretical framework, and the theory encourages organisations to determine the "power, legitimacy, and urgency" of stakeholders with whom they interact. A qualitative approach was used in this study. The data collection method was semi-structured interviews for all 12 participants. Data were analysed through a deductive thematic approach to identify, analyse and report patterns or themes within the data collected. The study showed that the wind farm unintentionally applies some components of responsible leadership among its stakeholders. Openness, transparency, and communication are critical actions that this organisation undertakes to cultivate trust among both its internal and external stakeholders. External stakeholders experience this organisation differently. There are mixed feelings regarding how the wind farm conducts its stakeholder engagement activities, particularly relating to landowners and government institutions. A stakeholder engagement framework is imperative if an organisation is to maintain cordial relations with its stakeholders. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2023
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- Date Issued: 2022-06
An appraisal analysis of a selection of Zapiro’s political cartoons
- Authors: Hussey, Thomas Davey
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406725 , vital:70302
- Description: Thesis embargoed. To be released in 2025. , Thesis (MA) -- Faculty of Humanities, Linguistics and Applied Language Studies, 2022
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- Date Issued: 2022-10-14
An Investigation into Speaker and Headphone-Based Immersive Audio for VR and Digital Gaming Applications
- Authors: Marais, Kyle Donald
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365246 , vital:65720
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Computer Science, 2022
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- Date Issued: 2022-10-14
Bioactivity evaluation of manno-oligosaccharides produced from spent coffee grounds using a Bacillus sp. derived endo-1,4-β-mannanase
- Authors: Magengelele, Mihle
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365233 , vital:65719
- Description: Thesis embargoed. Possible release date set for early 2024. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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- Date Issued: 2022-10-14
Characterisation of two novel ferrocenyl benzoxazines as in vitro triple-negative breast cancer inhibitors
- Authors: Mhlanga, Richwell
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365689 , vital:65776
- Description: Thesis access embargoed. Expected released date early 2025. , Thesis (PhD) -- Faculty of Science, Biochemistry and Microbiology, 2022
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- Date Issued: 2022-10-14
Contextualising job satisfaction amongst lowest paid support staff in a Higher Education institution
- Authors: Madito, Gotlannamang Moloiesi Boipelo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405984 , vital:70225
- Description: Thesis embargoed. To be relased in 2024. , Thesis (MA) -- Faculty of Humanities, Psychology, 2022
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- Date Issued: 2022-10-14
Country risk and stock market volatility in Africa: Measuring the contribution of political and economic risk factors
- Authors: Hoveni, Jamela Basani
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/405445 , vital:70172
- Description: Thesis embargoed. To be released in 2025. , Thesis (PhD) -- Faculty of Commerce, Economics and economic History, 2022
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- Date Issued: 2022-10-14
Development of biosensor systems for the detection of anti-cancer drugs and prostate cancer
- Authors: Mwanza, Daniel
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365929 , vital:65803
- Description: Thesis embargoed. Expected release date early 2025. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
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- Date Issued: 2022-10-14
Dual and targeted photodynamic therapy ablation of bacterial and cancer cells using phthalocyanines and porphyrins in the presence of carbon-based nanomaterials
- Authors: Openda, Yolande Ikala
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Doctoral theses , text
- Identifier: http://hdl.handle.net/10962/365945 , vital:65804 , DOI https://doi.org/10.21504/10962//365946
- Description: Phthalocyanines (Pcs) and porphyrins bearing substituents that possess antibacterial/anticancer properties are used as photosensitizers (PS) for the first time in the work. For targeting specificity and improved photoactivity, the PSs were afterward functionalized with carbon nanomaterials such as graphene quantum dots (GQDs) and detonation nanodiamonds (DNDs) via covalent conjugation (amide or ester bonds) or by non-covalent conjugation (π-π stacking and electrostatic interactions). Furthermore, the PSs-DNDs nanoconjugates were conjugated to either chitosan-capped silver nanoparticles (CSAg) via amide bonds or to the bare silver nanoparticles (Ag NPs) using the silver- nitrogen affinity. The as-synthesized nanoconjugates were also fully characterized by spectroscopic and microscopic methods together with thermal analysis. The potential photocytotoxicity of the complexes alone and their nanoconjugates against S. aureus and/or E. coli planktonic and biofilm cultures has been evaluated in vitro. Compared to the non- quaternized PSs, the cationic analogs exhibited a higher photodynamic inactivation against the planktonic cells with log10 reduction values above 9 in the viable count using a concentration of ca. 1.25 μM following 30 min exposure to light (Light dose: 943 J/cm2 for Pcs and 250 mW/cm2 for porphyrins). Whereas, at a concentration of ca. 100 μM the cationic PSs showed complete eradication of biofilms upon 30 min exposure to light. As a result of conjugation to carbon-based nanomaterials and silver nanoparticles, the compounds proved to be more effective as they exhibited stronger antibacterial and anti-biofilm activities on the multi-drug resistant bacteria strains due to synergetic effect, compared to PSs alone. This suggests that the newly prepared nanohybrids (PS concentration ca. 100 μM) could be used as potential antimicrobial agents in the treatment of biofilm-related infections. The target nanoconjugates showed all the advantages of two different groups existing on a single entity. In light of the potential advantages of combined chemotherapy and photodynamic antimicrobial chemotherapy (PACT), this work reports for the first time the use of PACT-ciprofloxacin (CIP) dual therapy using selected indium quaternized PSs which showed higher photoactivity with complete eradication of both Gram-positive and Gram-negative bacteria biofilms at concentrations of 8 μM of PS versus 2 μg/mL of the antibiotic following 15 min irradiation time (light dose: 471 J/cm2 for Pcs and fluence: 250 mW/cm2 for porphyrins) on S. aureus. Whereas the total killing of E. coli was obtained when combining 8 or 16 μM of PS combined with 4 μg/mL of CIP. The combined treatment resulted in the complete eradication of the matured biofilms with the highest log10 reduction values of 7.05 and 7.20 on S. aureus and E. coli, respectively. Used as a model, positively charged dimethylamino-chalcone Pcs also exhibited interesting photodynamic therapy (PDT) activity against MCF-7 cancer cells giving IC50 values of 17.9 and 7.4 μM, respectively following 15 min irradiation. Additionally, the TD-B3LYP/LanL2DZ calculations were run on the dimethylaminophenyl- porphyrins to compare the singlet excitation energies of quaternized and non-quaternized porphyrins in vacuo. the study shows excellent agreement between time-dependent density- functional theory (TD-DFT) exciting energies and the experimental S1>S0 excitation energies. The small deviation observed between the calculated and experimental spectra arises from the solvent effect. The excitation energies observed in these UV-Vis spectra mostly originated from electron promotion between the highest occupied molecular orbital (HOMO) for the less intense band and the HOMO-1 for the most intense band of the ground states to the lower unoccupied molecular orbital (LUMO) of the excited states. , Thesis (PhD) -- Faculty of Science, Chemistry, 2022
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- Date Issued: 2022-10-14
Evaluating the role of Stress Induced Phosphoprotein 1 isoforms in Kaposi's Sarcoma-Associated Herpesvirus biology
- Authors: Ruck, Duncan Kyle
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/365280 , vital:65723
- Description: Thesis embargoed. Possible release date set for early 2025. , Thesis (MSc) -- Faculty of Science, Biochemistry and Microbiology, 2022
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- Date Issued: 2022-10-14
Evaluating the trophic ecology and feeding habits of three divergent lineages of Sandelia bainsii (Teleostei: Anabantidae), from the Eastern Cape Rivers using stable isotope analysis
- Authors: Nkomo, Thulisile
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/364984 , vital:65667
- Description: Despite supporting a disproportionately large fraction of the global biodiversity, freshwater ecosystems are ranked as the most highly threatened habitats on the planet, ahead of both terrestrial and marine ecosystems. Many regions are still characterised by limited knowledge regarding the taxonomy and ecology of freshwater fish taxa. The need for ecological information is increasingly becoming important due to the discovery of new species and unique lineages, which require conservation management. The aim of this study was thus to evaluate the trophic ecology and feeding habits of the three recently described and divergent Sandelia bainsii lineages, namely Sandelia sp. ‘bainsii Kowie’ from the Great Fish River, Sandelia sp. ‘bainsii Keiskamma’ found in the Keiskamma River, and Sandelia sp. ‘bainsii Buffalo’ confined to the Buffalo River system in the Amathole-Winterberg freshwater ecoregion in the Eastern Cape Province, South Africa. Based on the allopatric distribution and the generalist feeding habits of these lineages, this thesis postulated that these three lineages were likely to show similar trophic ecology patterns, different dietary composition and as a result would have variable trophic positioning in the different river systems. Therefore, the primary objectives were to use stable isotope analysis to (1) evaluate the food web patterns of the river systems where the three S. bainsii lineages occurred, and (2) determine dietary source contributions for the three lineages using isotope mixing models. The results revealed general variability and significant differences in the δ13C and δ¹⁵N values for the different basal resources, macroinvertebrates and fish community across the different headwater streams. Within and across the different rivers, the S. bainsii lineages exhibited variable isotopic niche sizes, which appeared to coincide with the variation in the isotopic composition of the individual communities. Furthermore, these lineages did not exhibit any discernible patterns in their interspecific interactions in different habitats. This suggests that these lineages’ isotopic niche patterns were largely influenced by spatial differences in both trophic resources and probable interactions with contraspecifics. Assessment of trophic positions of S. bainsii lineages showed that the three lineages had higher trophic positions than other co-occurring species at most sites, except in the Buffalo River. This suggest that the different lineages were generally top predators in the different river systems. Although S. ‘bainsii Buffalo’ had a lower trophic position compared to other co-occurring species, its trophic position was generally characterised by high uncertainty, indicating that this lineage was likely influenced by the occurrence of diet sources that had highly variable stable isotope values. Findings from stable isotope mixing models revealed that the diet sources varied from the dominance of either single diet source in the Fairburn and Tyume 1 River to the importance of multiple prey sources from the Lushington and Kat River system. This suggests that despite being a top predator at most sites, the diet sources for the different lineages were highly variable. The patterns observed in this study did not appear to be attributed to species divergence possibly caused by allopatric speciation, but rather differences in food web characteristics of the river systems, as well as the lineages interspecific relationships and their generalized feeding strategies. Understanding the trophic dynamics of these lineages will assist in implementing effective conservation strategies and policies dealing with narrowly distributed species that are threatened by habitat fragmentation and invasion of piscivorous fish. , Thesis (MSc) -- Faculty of Science, Ichthyology and Fisheries Science, 2022
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- Date Issued: 2022-10-14
Exploration of remote work and wellbeing of academics in a South African tertiary institution
- Authors: Chikutu, Michelle
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405963 , vital:70223
- Description: Thesis embargoed. To be released in 2024. , Thesis (MA) -- Faculty of Humanities, Psychology, 2022
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- Date Issued: 2022-10-14
Exploring integration for the topic of stoichiometry in South African natural sciences and physical sciences school curricula
- Authors: Mgolozeli, Kwanele
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405330 , vital:70162
- Description: Many developing countries, including South Africa, have identified the provision and implementation of strong science curricula as central to their developmental needs. Stoichiometry is a fundamental chemistry topic because the concepts involved form the basis of later topics such as chemical equilibrium, rates of reactions, redox reactions, and acid-base reactions. School students consistently demonstrate lack of understanding of stoichiometry-related concepts and skills such as the particulate nature of matter and related mathematical problem-solving. The poor performance of high school students in central science topics such as stoichiometry is problematic for their further study of chemistry and for the country meeting its need for science graduates. Successive examiner reports pointed to the lack of integration of stoichiometry concepts across the grades being the main problem. However, no study could be found which explores how stoichiometry is integrated in the South African Natural Sciences and Physical Sciences curriculum across the grades. This provided the rationale for the current study. The case study reported in this thesis thus aimed to explore integration of stoichiometry concepts in South African Natural Sciences and Physical Sciences school curricula. It involved document analysis as the method of collecting data. The research adopted the social realist paradigm, with its realist ontology and relativist epistemology. Legitimation Code Theory provided the theoretical framing. Chemistry concepts that are foundational to the understanding of stoichiometry according to literature, were chosen as root concepts for the concept mapping undertaken to identify types of integration. The concept maps revealed four stoichiometry integration themes: integration of stoichiometry concepts with symbols, integration of stoichiometry concepts with explanations, integration with applications in a chemistry context, and integration with an everyday context. These themes provided integration categories. A semantic gravity translation device was then developed for characterising the types of integration in terms of the degree of contextualisation. The results of this study show that stoichiometry integration of weaker semantic gravity is legitimated more strongly over other semantic gravity codes in the Natural Sciences and Physical Sciences curricula across all grade levels. While this has advantages in terms of knowledge-building potential, the consequence is that the integration occurs at very abstract levels that are far removed from learners’ everyday lives. The practical implication for curriculum developers involves increasing the instances of integration of stoichiometry concepts at stronger levels of semantic gravity, for a more even semantic gravity range of integration types. Natural Sciences and Physical Sciences teachers also need to source and include real-life examples for explanations and applications of stoichiometry concepts when teaching, in light of current curriculum documents focusing more on abstract forms of integration. Methodologically, this study contributes to the increased utility of semantic gravity through its exploration of integration in relation to knowledge-building potential of curriculum for hierarchical knowledge structures such as chemistry. , Thesis (MEd) -- Faculty of Education, Education, 2022
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- Date Issued: 2022-10-14
Exploring primary school mathematics teachers use of gamification in formative assessment: a case study
- Authors: Simelane, Thando
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/405412 , vital:70169
- Description: Technology integration has gained much influence with the emergence of technological tools in educational areas. The vast resources and opportunities that technologies and the Internet have brought new approaches, strategies, and tools to assess learners' performance in many subject areas. Teachers have many computer/mobile device applications and learning management systems. Most teachers are trying new ways of integrating technology into the mathematics classroom to increase the quality of teaching and learning. Thus, this study explored how primary school mathematics teachers use Kahoot as a formative assessment tool. The study adopted an exploratory case study underpinned by the interpretive paradigm. It was conducted in a primary school in the Shiselweni Region in Swaziland. The participants were ten mathematics teachers teaching different grades at the school. Data was generated using observations, workshops, structured questionnaires, journal reflections and focus group interviews. The theoretical and analytical framework that underpinned this study was a combination of Davis' (1989) Technology Acceptance Model (TAM) and Mishra & Koehler's (2006) Technological Pedagogical Content Knowledge (TPACK) framework. The study results showed that the perceptions and attitudes of primary school mathematics teachers towards using Kahoot generally appear to be positive. The study also revealed that all the participants found Kahoot helpful and perceived it as easy to use. The study found that the provision of technical support for teachers; and financial support for schools to implement technology use in the classroom were enabling factors for using Kahoot as a formative assessment technology. Constraining factors were lack of high-speed internet connectivity; and lack of basic technological knowledge for using Kahoot in formative assessment. The study concluded that Kahoot increases learner motivation, engagement, attention, enjoyment, and knowledge retention. This study recommended the integration of Kahoot gamification into the mathematics curriculum.The study recommends that there is a need for schools to initiate the presence of technologies in mathematics classrooms and encourage teachers to integrate technologies assessment and teaching. The study suggest future research to explore use of Kahoot as a formative assessment technology in resource-constrained schooling contexts using multiple cases. , Thesis (MEd) -- Faculty of Education, Education, 2022
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- Date Issued: 2022-10-14
Exploring the influence of student protests on organisational citizenship behaviour of academics and support mechanisms in higher learning institutions
- Authors: Mayekiso, Sinovuyo
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406198 , vital:70248
- Description: Embargoed. To be released in 2024. , Thesis (MA) -- Faculty of Humanities, Psychology, 2022
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- Date Issued: 2022-10-14
Global climate justice: the case of climate migrants
- Authors: Van Heerden, Samantha Jane Ashburner
- Date: 2022-10-14
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/406749 , vital:70304
- Description: Climate change is predicted to displace thousands of people across the globe. Due to their geographical location and limited resources available for adaptation, this will particularly impact those in developing states, who might have to flee from the growing frequency and severity of rising sea levels, drought and desertification, and acute natural disasters such as floods, wildfires, and hurricanes. This is likely to have pervasive effects on the moral interests of those affected, threatening loss of life, the deterioration of livelihoods, and for small island states even complete or substantial loss of state territory. In this thesis I will argue that we should conceive of this situation as a problem of global justice. Though some argue that questions of justice only arise within the state, I will argue that global economic and political institutions have contributed to the plight of climate migrants, and that following from Darrel Moellendorf’s theory of associational justice, this enduring impact results in an association and duties of justice that transcend state borders. To respect the dignity of climate migrants, such an unjust association needs to be rectified by establishing ethical principles that could be reasonably endorsed by everyone affected. Drawing from Gillian Brock, I will argue that the best way to rectify the situation is through establishing a principle of distributive justice which focuses on ‘agency needs’: needs whose fulfilment is necessary for human agency. Using this framework, I then provide some recommendations of what is owed to climate migrants to achieve justice for them. I also consider how these duties of justice should be distributed, first critiquing a dominant approach that attributes duties primarily to polluters. In the end, I recommend that duties should be dispersed between all those who support the global institutions responsible, those who have been high polluters since 1990, and the most affluent in the world. As the effects of climate change become increasingly pronounced within the next fifty years, establishing what is owed to those displaced is of utmost importance, and I hope this thesis shows how normative philosophy can help us think through these urgent questions. , Thesis (MA) -- Faculty of Humanities, Philosophy, 2022
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- Date Issued: 2022-10-14