Showing items 1 - 20 of 1339

Your selections:

A model of the value provided by smartwatches related to physical activity

  • Authors: Bekker, Carmen
  • Date: 2025-04
  • Subjects: Smartwatches , Wearable computers , Medical care -- Technological innovations
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75490 , vital:79930
  • Description: Adopting smartwatches for personal physical activity (PA) management has become a popular trend. Prior research has investigated the factors that impact the continued usage of smartwatches. However, studies have yet to focus on the value that smartwatches provide to their users, the factors that impact smartwatch value and the data management (DM) techniques that enable the collection of PA data. DM techniques and frameworks usually relate to Internet of Things (IoT), wearable, or smartwatch datasets. However, these techniques and frameworks do not provide sufficient detail related to the specific techniques and standard practices to manage smartwatch PA data, the value provided by the smartwatches related to PA and the factors influencing the value experienced by the end-users. Data management ensures that value is derived from data; in this case, PA data collected by smartwatches. The research attempts to answer the main research question: What value is provided by smartwatches related to the physical activity of users? Three research objectives guided the study: (1) Determine the factors that influence the value that smartwatches provide to users relevant to their PA; (2) Evaluate the success and value that smartwatch platforms provide related to the DM techniques of PA data and (3) Investigate the value that smartwatches provide to users related to their PA data. A mixed-method approach using the Framework for an Integrated Methodology (FraIM) was used to collect the data for this study. A combination of quantitative (numerical) and qualitative (narrative) data was collected to assist in determining the factors that impact smartwatch value and how PA data in smartwatches is managed. The numerical data was collected using online surveys and PA data that was collected autonomously from participant smartwatches over a 28-day period. The narrative data was collected from secondary sources and analysed using document and comparative analyses of the smartwatch manufacturers’ documents and websites. The Smartwatch Value Model (SVM) for PA was developed based on underlying theoretical frameworks related to continued usage intention models for smartwatches. The model consists of five constructs: Demographics, Smartwatch Usage, PA, Smart Device Features and Value; and illustrates how the first four impact the fifth construct, Value, which is provided by smartwatches for PA. Value is further classified into utilitarian, hedonic and social value. The SVM was evaluated using document and comparative analysis for the narrative data, and statistical methods for the numerical data. , Thesis (MCom) -- Faculty of Science, School of Mathematical & Computational Sciences Cluster, 2025
  • Full Text:
  • Date Issued: 2025-04

Abundance and distribution of mesozooplankton communities on the southern and central Mozambique shelf

  • Authors: Chioze, Ceiça Alfredo
  • Date: 2025-04
  • Subjects: Zooplankton -- Mozambique , Marine zooplankton -- Mozambique , Estuarine ecology -- Mozambique
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75602 , vital:79969
  • Description: Mesozooplankton are a crucial component of marine ecosystems, influencing food web dynamics by transferring energy to higher trophic levels. Their abundance and distribution provide valuable information on ecosystem health, productivity, and potential fishing areas. Previous studies using satellite chlorophyll-a data identified Angoche, Sofala Bank, and Delagoa Bight as the most productive areas on the Mozambique shelf. This study aimed to examine mesozooplankton distribution, abundance, biomass, biovolume, and community structure along the Mozambique shelf using data from two ship surveys: (i) SA Agulhas II on Sofala Bank in October 2017 and (ii) Dr. Fridtjof Nansen on Sofala Bank and southern Mozambique in February-March 2018. Semi-seasonal variations were considered, as the 2017 survey occurred in early summer (October) and the 2018 survey in late summer (February-March). Sampling grids differed too with the former focused on the Sofala Bank (central shelf region), whilst the latter was along the Sofala Bank and southern Mozambique shelf. Results showed mesozooplankton abundance and biovolume were consistently higher at nearshore stations in both years. In 2017, peaks in abundance were observed near the Zambezi River mouth and between Quelimane and Pebane on the Sofala Bank. Higher biovolume was found north of Beira and south of the Zambezi Delta. In 2018, the highest abundance and biovolume occurred along the Sofala Bank and Inhambane terrace. Multivariate analysis revealed a link between higher chlorophyll-a) and higher mesozooplankton abundance. These areas experience upwelling events and riverine influence, promoting higher productivity. Copepoda were the dominant mesozooplankton taxa in both years, followed by Appendicularia and Chaetognatha. Interannual variations in environmental drivers, particularly upwelling intensity, river discharge, and nutrient availability, likely influence the distribution and abundance of mesozooplankton communities. The southward extent of the Zambezi River plume may also influence brackish and freshwateradapted taxa. Additionally, the study identified larval stages of commercially valuable decapod crustaceans and fish larvae within the meroplankton community, highlighting the shelf role as a spawning ground and its importance for fisheries. Furthermore, the presence of uncommon/rare taxa like Monstrilloida and Facetotecta indicates a potentially richer fauna than previously documented. This underlines the need for further taxonomic exploration to understand their ecological roles and potential as indicator species. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Alkaloidal detection, isolation and anticancer activity of cissampelos capensis L. f.

  • Authors: Visagie, Shahlaa
  • Date: 2025-04
  • Subjects: Phytochemicals -- Analysis , Cancer -- Treatment , Cancer -- Research
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76270 , vital:80183
  • Description: Cancer is a serious health crisis affecting South Africa, and finding effective treatments is important. Plants contain various phytochemicals that may help combat diseases such as cancer due to their biological activities. One such plant is Cissampelos capensis L. f., traditionally used by locals in the Eastern Cape for cancer management. Phytochemical groups associated with anticancer activity include alkaloids. Recent research in our laboratory has highlighted the alkaloidal profile and cytotoxicity of the C. capensis rhizome as a potential anticancer treatment. The study made use of High-Performance Thin-Layer Chromatography (HPTLC) with Dragendorff spray reagent, column chromatography (cc), and preparative Thin-Layer Chromatography (prepTLC) for compound detection and isolation. The results confirmed the presence of alkaloids in the various C. capensis extracts. Several groups of alkaloids, such as isoquinoline, quinazoline, and vanilloid alkaloids, were tentatively identified through Liquid Chromatography-Mass Spectrometry (LC-MS), literature comparison, and the Global Natural Products Social Molecular Networking database. Furthermore, two novel compounds were isolated and tentatively identified through structural elucidation as cissamcapine (40) and cissamcapaline (41). In vitro cytotoxicity studies via the Resazurin assay against MCF12A (non-tumorigenic human mammary epithelial cells), MCF-7 (breast cancer cells), MDA-MB-231 (triple-negative breast cancer cells), and HeLa cells (cervical cancer cells), revealed that the Only methanolic C. capensis rhizome crude extract (OMCCR) and compound 41 had the highest cytotoxicity, showing selectivity towards the breast cancer cell line. Additionally, in silico anti-breast cancer studies were conducted to assess the drug-likeness and molecular interactions of the identified compounds. All the compounds conformed to Lipinski’s rule of five, and molecular docking showed that compounds 21 and 32 had the highest binding affinities for protein 2IOK, while compounds 23 and 34 outperformed their co-crystals in 4OAR and 4RJ3, respectively. Furthermore, the isolated compounds 40 and 41 had comparable docking scores with their co-crystals against 4OAR (40: -8.16 kcal/mol; 41: -7.62 kcal/mol; co: -8.90 kcal/mol) and 4RJ3 (40: -5.90 kcal/mol; 41: -5.86 kcal/mol; co: -6.81 kcal/mol), suggesting similar theoretical binding strengths. These findings contribute towards understanding the chemistry and anticancer potential of C. capensis plant extracts. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

An information architecture for a first-year programming module on the Moodle learning management system : a Nelson Mandela University case study

  • Authors: Kafile, Asanda
  • Date: 2025-04
  • Subjects: Moodle , Computer-assisted instruction -- Authoring programs , Open source software
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75821 , vital:80042
  • Description: Students enrolled in first‐year programming modules at higher education institutions often have difficulty in mastering the modules (Van Heerden & Goosen, 2019; Figueiredo & García- Peñalvo, 2024). According to Cao, Seow, Lim, Keoh, Dale, Honeychurch, Tasler & Bremner (2023) despite the implementation of various pedagogical approaches, including blended learning to enhance student performance, many students continue to face difficulties with programming modules. The use of online learning platforms, such as Learning Management Systems (LMSs), to facilitate teaching of, for example, programming modules, necessitates the structuring of course content in such a way that students can easily find and digest the learning material. Furthermore, the learning materials used must accommodate the students' various learning styles to effectively support their learning experiences. This research aimed to determine the effectiveness of using an Information Architecture (IA) explicitly designed for structuring different types of content in online courses, with the goal of supporting students’ diverse learning styles. This research focused on a first-year programming module of the Nelson Mandela University (NMU) Department of Computing Sciences and used Modular Object-Oriented Dynamic Learning Environment (Moodle) as the LMS. This study included a group of first-year programming students, a learning experience (LX)designer (LT-Collab staff member), and the first-year programming lecturer from theNMU Department of Computing Sciences as participants. This study adopted Design Science Research (DSR) as the research methodology and applied the DSR process model to this research. DSR seeks to develop knowledge about how artefacts can and should typically be arranged or built by humans to accomplish desired goals (Hevner et al., 2008). Through the DSR process model, this study used a literature review, a questionnaire, interviews, and Focus Group Discussions (FGDs) to identify the most suitable methods of structuring learning content in LMSs to create an IA that allows the lecturer of a first-year programming module to present learning materials that cater to different learning styles. The results showed that the students preferred to learn programming using learning materials such as videos, exercises, voice-over slides, and lecture notes that enable them to practically engage with the material. To accommodate for different learning styles, the LX designer highlighted the significance of using a universal design while developing online courses. This study made both practical and theoretical research contributions. For the practical component, IA was developed to structure the learning materials of a first-year programming module in the Department of Computing Sciences at NMU in the Moodle LMS. The theoretical contribution was the proposed guidelines for developing an IA for a first-year programming module, specifically for providing learning materials that encourage student engagement and to support students’ diverse learning styles in LMSs. , Thesis (MSc) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2025
  • Full Text:
  • Date Issued: 2025-04

Ant colony optimisation based routing and wavelength assignment algorithm for transparent flexi-grid optical burst switched networks using link usability metric

  • Authors: Oladipo, Joshua Femi
  • Date: 2025-04
  • Subjects: Mathematical optimization , Ants -- Behavior -- Mathematical models , Distributed algorithms
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/76144 , vital:80167
  • Description: The increasing demand for high-bandwidth applications such as video streaming and cloud computing is driving the evolution of optical networks to manage dynamic traffic patterns more efficiently. Among emerging paradigms, Optical Burst Switching (OBS) over transparent flexi-grid networks shows great promise for optimising resource utilisation compared to traditional Optical Circuit Switching (OCS). However, two key challenges hinder its adoption, namely, high burst loss due to contention in OBS and the heightened susceptibility of flexi-grid systems to optical impairments. Addressing these limitations is critical to harnessing the full potential of these technologies This thesis investigates the application of Ant Colony Optimisation (ACO) algorithms to solve the Routing and Wavelength Assignment (RWA) problem in flexigrid OBS networks. Building on prior work that developed the Flexible Spectrum Ant Colony (FSAC) and Congestion Measure Flexible Spectrum Ant Colony (CMFSAC) algorithms, this study introduces a novel approach: the Usability Metric Flexible Spectrum Ant Colony (UM-FSAC). The UM-FSAC algorithm incorporates a dynamic “Link Usability” metric that evaluates network link quality based on fragmentation and wavelength utilisation, enabling more effective resource allocation. Performance evaluation reveals that UM-FSAC significantly reduces Burst Loss Probability (BLP) compared to earlier algorithms. Additionally, this study provides a holistic analysis of network performance, considering metrics such as fairness and efficiency, to offer deeper insights into the broader impacts of ACO-based RWA strategies. Furthermore, the algorithms are benchmarked against analytical and heuristic lower bounds from the literature, providing a robust assessment of their practical effectiveness under various network conditions. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2025
  • Full Text:
  • Date Issued: 2025-04

Anti-diabetic effects of green synthesized cerium oxide nanoparticles (CeO2-NPs) using oleanolic acid in liver and skeletal muscle cell lines

  • Authors: Livhalani, Zwivhuya
  • Date: 2025-04
  • Subjects: Diabetes , Medicinal plants -- South Africa , Biomedical materials
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75976 , vital:80103
  • Description: Diabetes mellitus, a global chronic disease, has, during the past decades, continued to rise. In recent years, even though the increment rate has slowed down, it remains a highly important priority for public health. Nanotechnology could greatly enhance the quality of life of individuals diagnosed with diabetes through its applications in management and treatment, including innovative blood sugar monitoring, targeted controlled insulin release, regenerative medicine, and enhanced wound healing. Recent developments in diabetes treatment using nanotechnology have attracted increasing interest due to their potential to improve patient outcomes. Accordingly, the current research aimed to investigate the anti-hyperglycaemic potential of green-manufactured CeO2 nanoparticles using oleanolic acid derived from Syzygium aromaticum methanolic cloves extract. Material and methods: In this study, CeO2 NPs were synthesized using pure oleanolic acid (Oleanolic Acid capped cerium oxide nanoparticles, OA-CeO2 NPs) and methanol clove extracts (Syzygium aromaticum methanolic crude cloves extract capped Cerium oxide nanoparticles, CCE-CeO2 NPs), and the physicochemical features were evaluated by spectrometry, electron microscopy and dynamic light scattering. The effects of CeO2 NPs on cell viability were determined using an MTT assay. The hypoglycaemic potential of CeO2 NPs was investigated using the glucose colourimetric assay on the human liver cancer cell line (HepG2) and mouse myoblast cell line (C2C12). The cells were treated for 0, 24, 48 and 72 hours with different concentrations of CeO2 NPs (1, 25, 50 and 100μg/mL), oleanolic acid (160μg/mL) and cloves crude extracts (160μg/ml) where metformin (160μg/mL) acted as a positive control. Results and Discussion: The average size range of synthesized CeO2 NPs diameter was 173±56 nm, with polydispersity index values of 0.28 and 0.20. The zeta potential of CeO2 NPs varied between - 22.7 mV to -36.8 mV. The CeO2 NPs showed no cytotoxic effects on both the cell lines as the results revealed no significant statistical variations between the treated cells and untreated cells following the MTT assay. Our data demonstrated a pronounced anti-hyperglycaemic effect, with glucose levels significantly decreasing from 21.60 ± 0.10 mmol/L to 5.0 ± 0.84 mmol/L in liver cells treated with OA-CeO2 NPs at the lowest dose (1 μg/mL). Conversely, the highest dose (100 μg/mL) of the CCE-CeO2 NPs significantly decreased glucose concentrations from 21.60 ± 0.10 to 4.90 ± 0.74 mmol/L in the HepG2 cell line. In the mouse myoblast cell line (C2C12), glucose concentrations declined to normal physiological levels of 4.5 -5 mmol/L following treatment at doses of 50 and 100 μg/mL of the OA-CeO2 NPs and at 25 μg/mL dose of the CCE-CeO2 NPs which reveals improved glucose utilization by the cells, as a result of the improved drug bioavailability, permeability, and solubility. The glycogen assay showed that C2C12 and HepG2 cells had an increase in glycogen concentration after administration of CeO2 NPs within the period of 72 hours compared to the negative control which correlate with the increase of glucose uptake by the cells. The green synthesized CeO2 NPs using oleanolic acid lowers glucose concentration in both muscle and liver cell lines without toxic effects on the cells. Furthermore, the CeO2 NPs restored the depleted glycogen following glucose utilization by the cells. These findings may lead to the development of CeO2 NPs synthesized using oleanolic acid for the management of diabetes mellitus with improved pharmaceutical qualities. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Consideration or Afterthought? An Assessment of Rehabilitation in projects authorised through the NEMA EIA process within the Eastern Cape

  • Authors: Casoojee, Riyadh Suliman
  • Date: 2025-04
  • Subjects: South Africa. -- National Environmental Management Act, 1998 , South Africa. -- Environment Conservation Act, 1989 , Sustainable development
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75512 , vital:79932
  • Description: South Africa is well known as a country committed to sustainable development, having it enshrined in Section 24 of its Constitution. Sustainable development is regarded as a cornerstone for shaping and advancing environmental law and policy, emerging as a response to the extensive environmental degradation and the looming climate crisis caused by human activities. In order to achieve sustainable development, multiple tools and legislative frameworks have been crafted, among the most prominent is the Environmental Impact Assessment (EIA). Appearing in the legal frameworks of over 180 countries EIAs promote sustainability, guiding government decisions on development with science-based insights into socio-environmental impacts. In South Africa, the EIA process is currently governed by the National Environmental Management Act 107 of 1998(NEMA) and the NEMA EIA Regulations of 2014 as amended. Key to the EIA process is the prediction of potential impacts and proposing mitigatory measures. These mitigations are informed by the Mitigation Hierarchy, a successional framework which prioritizes avoiding and minimizing impacts, followed by rehabilitation of impacted areas, and, as a last resort offsetting. Environmental rehabilitation seeks to repair ecological degradation caused by development activities. However, despite its importance for promoting sustainable development, neither the NEMA nor its EIA Regulations provide clear guidance on the standards or content of effective rehabilitation planning. This ambiguity raises concerns about the consistency and efficacy of post-development rehabilitation measures in South Africa. Thus, the research presented in this thesis aimed to explore this gap in the legislation and to assess the current quality of rehabilitation planning and outcomes in the EIA process of South Africa. Firstly, I examined the inclusion of environmental rehabilitation and rehabilitation planning within South African Environmental Legislation pertaining to the EIA process. The analysis revealed significant gaps, a lack of guidance, vague regulation and inconsistent practices which would hinder effective rehabilitation planning and implementation. Using the Society for Ecological Restoration’s International Principles and Standards for the Practice of Ecological Restoration (SER IPS) as a benchmark, I then assessed the quality of rehabilitation plans within the EIA reports for 15 environmentally authorised developments. Findings reveal that 60% (9/15) of the plans were of inadequate quality, characterised by deficiencies in baseline inventories, reference ecosystems, monitoring protocols, and measurable rehabilitation goals. These shortcomings highlight the absence of legislative guidance, exacerbating the challenges in ecological recovery. Lastly, using the SER IPS “Five-star System” and “Ecological Recovery Wheel” methodologies, the rehabilitation outcomes of the same 15 environmentally authorised developments were assessed. It was found that only 47% (7 of 15) of projects achieved acceptable rehabilitation outcomes, equating to 7.15 ha of 14.6 ha that were rehabilitated. These deficiencies raise concerns about the effectiveness of EIAs in promoting sustainable development. The findings of this thesis highlight the urgent need for strengthened legislative frameworks and further research to enhance sustainable development and environmental rehabilitation within the EIA process in South Africa. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Continuous flow synthesis of lenalidomide key intermediate

  • Authors: Moreku, Clementine
  • Date: 2025-04
  • Subjects: Organic compounds -- Synthesis , Flow chemistry , Chemistry, Organic
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76037 , vital:80109
  • Description: Continuous flow synthesis has emerged as an innovative technology and is progressively becoming popular in the pharmaceutical industry. The flow technology offers accelerated, safer automized chemical reactions in high throughput and purity. The motive of this research was to exploit the continuous flow systems, to develop an effective synthetic method for the synthesis of 3-(4-nitro-1-oxoisoindolin-2-yl) piperidine-2,6-dione, a key intermediate towards the synthesis of lenalidomide, an anti-cancer drug. Additionally, to explore the effect of flow parameters (residence time, temperature, mole equivalent and type of solvent) on the conversion and selectivity of the reactions. Herein, we detail a comprehensive background on multiple myeloma cancer (MM), introduce lenalidomide (anti-cancer drug) and its analogues, and outline the issue of drug supply chains in Africa. Additionally, a brief introduction on the game-changer continuous flow technology, detailing its benefits and different reactors based on their properties and functions. A four-step synthetic route was established in batch and translated to continuous flow system. The optimized continuous flow route towards the synthesis of the 3-(4-nitro-1-oxoisoindolin-2-yl) piperidine-2,6-dione, a key intermediate afforded 96 % yield and 98 % HPLC purity at 100 ºC in 4 minutes residence time using THF solvent in an OMNIFIT column reactor. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Continuous flow synthesis of tafenoquine derivatives

  • Authors: Klaas, Lulama
  • Date: 2025-04
  • Subjects: Flow chemistry , Chemical engineering , Pharmaceutical preparations -- Standards
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75965 , vital:80102
  • Description: Continuous flow processing is of interest to the pharmaceutical industry because it offers cost efficiency, reduces environmental impact, improves safety, enhances product quality, speeds up development and scale-up, and saves space and energy. The focus of this research work was to exploit continuous flow systems, to develop a continuous flow process that is high yielding using commercial micro reactors to synthesize tafenoquine squaramide derivatives that may exhibit greater anti-malarial activity than the parent drug. In this thesis, a successful study on the individual translation of the batch synthesis of the three tafenoquine squaramide derivatives into optimized continuous flow syntheses is demonstrated. A comprehensive literature review and background on malaria, as well as an introduction to squaramide’s and their role in enhancing drug efficacy, in addition to a brief introduction to continuous flow technology with its advantages and comparison to classical batch methods are provided in the first and second chapters. Chapter three details the experimental procedures utilized for both batch and continuous flow syntheses. The continuous flow synthesis of the three tafenoquine derivatives proved to be far superior compared to their batch syntheses; excellent improvements in reaction yields, in addition to tremendously shorter reaction times were observed. The batch synthesis of a tafenoquine squaramide derivative (3-((4-((2,6-dimethoxy-4-methyl-5-(3-(trifluoromethyl)phenoxy)quinolin-8-yl)amino)pentyl)amino)-4-methoxycyclobut-3-ene-1,2-dione) had a reaction time of 48 hours and a yield of 48%. Whereas in continuous flow, it had a reaction time of 15 minutes, with a conversion of 78%. For another tafenoquine squaramide (3-((4-((2,6-dimethoxy-4-methyl-5-(3-(trifluoromethyl)phenoxy)quinolin-8-yl)amino)pentyl)amino)-4-butoxycyclobut-3-ene-1,2-dione) in batch synthesis, the reaction time was 12 hours with a yield of 70%, in continuous flow synthesis, this yield increased to 91% in just 15 minutes. The batch synthesis of squaramide 3-((4-((2,6-dimethoxy-4-methyl-5-(3-(trifluoromethyl)phenoxy)quinolin-8-yl)amino)pentyl)amino)-4-butylaminocyclobut-3-ene-1,2-dione had a reaction time of 24 hours and the yield was 76%, in flow the reaction time is 10 minutes with 91% conversion. This is expounded in chapter four with detailed discussions of the results attained during the continuous flow optimization of each step within the scope of this research are provided. The concluding remarks, the impact of this study and future work are elucidated in chapter five. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Determinants of market-related parameters considered by small-scale farmers before marketing their produce: a case of cassava farmers in South Africa

  • Authors: Tshishonga, Zwivhuya Osvaldo
  • Date: 2025-04
  • Subjects: Cassava , Farmers -- South Africa , Farms, Small -- South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75329 , vital:79914
  • Description: Cassava (Manihot esculenta) plays a vital role in enhancing food security due to its resilience to climate change and multipurpose use, such as food to communities, animal feeds, and raw materials for industries. However, small-scale cassava farmers in South Africa encounter a variety of barriers that impede their ability to effectively market their cassava produce. These barriers are influenced by an interplay of market-related, socioeconomic, and institutional factors, as well as challenges related to both production and marketing processes. This study sought to contribute towards the existing knowledge on small-scale farmers' market participation by analysing the socioeconomic and institutional factors influencing market-related parameters considered before selling cassava in the Limpopo, Mpumalanga, and KwaZulu-Natal provinces. Specifically, the study aims to identify and analyse market-related parameters that small-scale cassava farmers consider before selling their produce. Secondly, the study seeks to examine the socio-economic and institutional factors that influence these market-related parameters. Finally, the study analysed production and marketing challenges encountered by small-scale farmers before selling cassava. Using a semi-structured questionnaire, data were gathered from 240 randomly selected small-scale farmers in Limpopo, Mpumalanga, and KwaZulu Natal. Descriptive statistics were used to identify market-related parameters and the challenges encountered by small-scale farmers. On the other hand, a probit regression model was used to analyse the factors influencing the identified market-related parameters. The statistical packages used to summarize and analyse the data were Excel and R version 4.4.1. Study findings reveal that small-scale farmers considered market price and demand as the primary parameters influencing selling decisions, with emergency harvest and peer/cooperative influence playing secondary yet statistically significant roles. Furthermore, the socioeconomic and institutional factors significantly shape decision-making. Female farmers were more likely to prioritize market price, reflecting their dominant role in cassava marketing. Larger farm sizes increased the probability of demand consideration, underscoring economies of scale. Educated farmers demonstrated a higher likelihood of resorting to emergency harvesting, indicating adaptive risk management. Cooperative membership reduced reliance on external influence, highlighting the role of collective bargaining.The identified production-related challenges that hinder farmers' participation in markets, including pests and diseases, weeds, lack of agrochemicals, soil erosion, and limited access to high-quality planting materials. Marketing-related challenge that hinder market participation was limited access to market information lack of government support, measurement issues at the point of sales, bad road networks, and difficulty encountered while harvesting. This study recommends that the government also implement a system that provides farmers with market information to enable them to make informed decisions regarding when and where to sell their products. Farmers should join cooperative farmer groups or clusters to take advantage of collective market opportunities and gain better access to inputs and other resources. Policymakers and government should prioritize investments in rural infrastructure, such as rural roads, especially in production areas and the transport system in general. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Science and Management Cluster, 2025
  • Full Text:
  • Date Issued: 2025-04

Determinants of market-related parameters considered by small-scale farmers before marketing their produce: a case of cassava farmers in South Africa

  • Authors: Tshishonga Zwivhuya Osvaldo
  • Date: 2025-04
  • Subjects: Cassava , Farms, Small -- South Africa , Agriculture -- Economic aspects -- South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76192 , vital:80175
  • Description: Cassava (Manihot esculenta) plays a vital role in enhancing food security due to its resilience to climate change and multipurpose use, such as food to communities, animal feeds, and raw materials for industries. However, small-scale cassava farmers in South Africa encounter a variety of barriers that impede their ability to effectively market their cassava produce. These barriers are influenced by an interplay of market-related, socioeconomic, and institutional factors, as well as challenges related to both production and marketing processes. This study sought to contribute towards the existing knowledge on small-scale farmers' market participation by analysing the socioeconomic and institutional factors influencing market-related parameters considered before selling cassava in the Limpopo, Mpumalanga, and KwaZulu-Natal provinces. Specifically, the study aims to identify and analyse market-related parameters that small-scale cassava farmers consider before selling their produce. Secondly, the study seeks to examine the socio-economic and institutional factors that influence these market-related parameters. Finally, the study analysed production and marketing challenges encountered by small-scale farmers before selling cassava. Using a semi-structured questionnaire, data were gathered from 240 randomly selected small-scale farmers in Limpopo, Mpumalanga, and KwaZulu Natal. Descriptive statistics were used to identify market-related parameters and the challenges encountered by small-scale farmers. On the other hand, a probit regression model was used to analyse the factors influencing the identified market-related parameters. The statistical packages used to summarize and analyse the data were Excel and R version 4.4.1. Study findings reveal that small-scale farmers considered market price and demand as the primary parameters influencing selling decisions, with emergency harvest and peer/cooperative influence playing secondary yet statistically significant roles. Furthermore, the socioeconomic and institutional factors significantly shape decision-making. Female farmers were more likely to prioritize market price, reflecting their dominant role in cassava marketing. Larger farm sizes increased the probability of demand consideration, underscoring economies of scale. Educated farmers demonstrated a higher likelihood of resorting to emergency harvesting, indicating adaptive risk management. Cooperative membership reduced reliance on external influence, highlighting the role of collective bargaining. The identified production-related challenges that hinder farmers' participation in markets, including pests and diseases, weeds, lack of agrochemicals, soil erosion, and limited access to high-quality planting materials. Marketing-related challenge that hinder market participation was limited access to market information lack of government support, measurement issues at the point of sales, bad road networks, and difficulty encountered while harvesting. This study recommends that the government also implement a system that provides farmers with market information to enable them to make informed decisions regarding when and where to sell their products. Farmers should join cooperative farmer groups or clusters to take advantage of collective market opportunities and gain better access to inputs and other resources. Policymakers and government should prioritize investments in rural infrastructure, such as rural roads, especially in production areas and the transport system in general. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Science & Management, 2025
  • Full Text:
  • Date Issued: 2025-04

Diet composition of black-backed jackal (Lupulella mesomelas) across contrasted land use through DNA metabarcoding

  • Authors: Roberts, Magan
  • Date: 2025-04
  • Subjects: Black-backed jackal , Carnivorous animals -- Conservation , Animal welfare
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76166 , vital:80171
  • Description: Mesocarnivores like black-backed jackals (Lupelella mesomelas) play significant ecological roles, yet their diets and interactions are often not well understood. In southern Africa, jackals exhibit dietary flexibility that is influenced by environmental factors and land use. This thesis explores the diets of black-backed jackals across different habitats and seasons using DNA metabarcoding to identify prey species found in their scats. The first study compared two methods for identifying prey species from jackal faecal samples at the Welgevonden Private Game Reserve in Limpopo, South Africa: microscopic cuticular hair analysis and DNA metabarcoding. Both methods detected 17 common species, primarily large and medium-sized ungulates. However, more than 60% of discrepancies in prey detection occurred with very small prey species (<5 kg). DNA metabarcoding successfully classified most mice, rats, shrews, and hares at the species level—providing a level of resolution that is not always achievable with microscopic cuticular hair analysis. The latter method requires substantial expertise to confidently distinguish small mammal species and relies heavily on reference guides, which can introduce challenges in prey identification. While both methods produced similar proportions of prey size categories, microscopic cuticular hair analysis appeared to overrepresent common duiker among smaller ungulates. This discrepancy may be attributed to the inherent challenges of hair identification, such as limited reference keys and potential observer bias. At Welgevonden, jackals primarily consumed large ungulates (>100 kg), followed by rodents, with medium-sized ungulates (26–100 kg) being less common and small ungulates (<26 kg) comprising a minor part of the diet. Seasonally, jackals slightly shifted their diet, increasing consumption of species linked to ungulate birthing seasons, such as fawns and afterbirths. In the dry season, they ate a higher proportion of larger ungulates, likely relying more on scavenging when other prey, like newborn fawns, fish, and mice, are less available. The high detection of brown hyena in the jackals' scats suggests that both species may scavenge the same carcasses. The second study examined how jackal diets varied across three distinct land-use types near Graaff-Reinet, in the Eastern Cape: a nature reserve, a game farm, and livestock farms. On livestock farms, jackals primarily consumed sheep, while on game farms, they favoured greater kudu. In contrast, jackals in the nature reserve had a more diverse and evenly iv distributed diet. Rodents were a consistent dietary component across all landscapes, while large ungulates (>100 kg) also formed a stable part of the diet in different land-use types. Seasonal shifts indicated that rodents were crucial during the dry season, while medium-sized ungulates were more important during the wet season. These findings highlight jackals' adaptability to varying prey availability and land management practices, offering insights into their ecological role and potential for human-wildlife conflict, especially in livestock farming areas. The combination of molecular and traditional microscopic methods demonstrates the utility of DNA metabarcoding in enhancing our understanding of mesocarnivore diets. The research provides valuable insights into species interactions, trophic dynamics, and broader implications for biodiversity conservation and human-wildlife coexistence. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Does ultraviolet radiation affect the thermoregulation and waking behaviour of the Eastern Dwarf Chameleon, Bradypodion ventrale?

  • Authors: Ah Sing, Tamlin
  • Date: 2025-04
  • Subjects: Ultraviolet radiation -- Physiological effect , Chameleons -- South Africa -- Eastern Cape , Lizards -- South Africa -- Eastern Cape
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75457 , vital:79927
  • Description: As ectotherms, reptiles bask in sunlight to regulate their body temperature. However, recent studies show that reptiles may be actively basking for ultraviolet light (UV) rather than temperature regulation. I aimed to assess whether UV influenced the thermoregulation and waking behaviour of the Eastern Dwarf Chameleon, Bradypodion ventrale. Three experiments were conducted in the laboratory: A UV-only gradient, an inversed gradient and a correlated gradient. The UV-only gradient was conducted to assess whether B. ventrale could actively regulate its UV exposure and whether females selected for higher UV exposures than male chameleons. The inversed and correlated gradients were conducted to assess whether B. ventrale was willing to lower and raise its body temperature below and above the species-specific preferred body temperature (Tpref), respectively, to maintain higher UV exposure. The experiments were conducted across all four seasons to account for any seasonal fluctuations in temperature and photoperiod. I found that B. ventrale can actively regulate its UV exposure and prioritised UV regulation over maintaining Tpref. However, chameleons were only willing to lower their body temperature below Tpref to maintain UV regulation and not willing to raise body temperatures above Tpref. Due to equipment limitations, it was unclear as to whether there was a difference in UV exposure preference between male and female chameleons. Once the influence of temperature was added, seasonal differences were found between the selected body temperatures of chameleons, suggesting that the physiology of B. ventrale is influenced by seasonal fluctuations in environmental temperature. Field observations were conducted to assess whether UV exposure, body temperature or predation pressure influenced the first movements of B. ventrale at sleep sites. Observations were made across all seasons to account for shifts in temperature and photoperiod. Chameleons were observed in the early mornings, from approximately 40 minutes before sunrise. When chameleons began shifting position or moving at their sleep site, the time of day, body temperature, ambient temperature and UVI were measured at the perch. I found that neither UV exposure, nor body temperature, nor predation influenced the first movements of B. ventrale. However, observations indicated that light may strongly influence the waking behaviour of B. ventrale, although this is still to be adequately assessed. Bradypodion ventrale were willing to raise body temperatures above Tpref for only short periods, meaning they could benefit from increasing environmental temperatures as they may not have to bask as long for thermoregulation and vitamin D3 synthesis. The influence of UV exposure on thermoregulation in the laboratory is not easily translated into nature as there may be other factors influencing thermoregulatory behaviour. Thus, future studies should consider conducting more field ii studies regarding UV exposure in this species to assess the influence of UV on temperature regulation properly. It is also suggested that future studies consider the influence of light on the waking behaviour of B. ventrale, specifically light from urban areas at night. This study provides the first record of active regulation of UV exposure in a dwarf chameleon from the Bradypodion genus, gives insight into how thermoregulation is affected by the presence of UV, and vice versa, in a laboratory setting and contributes to the growing field of research on the importance of UV exposure in reptiles. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Effects of digital elevation model data resolution on hydrological modelling using SWAT: a case study of the Swartkops river catchment

  • Authors: Loni, Litha
  • Date: 2025-04
  • Subjects: Digital elevation models -- South Africa , Hydrology -- South Africa , Water-supply -- South Africa
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75987 , vital:80104
  • Description: Digital Elevation Models (DEMs) are widely used as input to model hydrological processes. Using the appropriate resolution of DEMs is critical in producing accurate simulations of hydrological processes using hydrological models such as the Soil and Water Assessment Tool (SWAT) model. As a result of the availability of DEMs in recent decades and land use/cover (LULC) change impacts on hydrological regimes, the aim of this study was to investigate the effect of DEM data resolution on SWAT model performance for analysing the hydrological response to LULC changes in the Swartkops River catchment. This included using the SWAT model to analyse runoff conditions in the catchment. The main objectives of the study were: (1) to generate LULC maps and analyse LULC changes using Multi-Temporal Landsat TM and OLI images from 1990 to 2022 within the Swartkops catchment using IDRISI Terrset and ArcMap 10.7; (2) to assess the influence of different DEM data resolutions on SWAT model performance via the quantification of model results; and (3) to utilise the SWAT model with optimal performance to analyse the impact of LULC change on the hydrological response (i.e., runoff generation) of the Swartkops catchment using ArcSWAT. To do this, 1990 and 2022 Landsat images were acquired, pre-processed, and classified using supervised image classification via the Maximum Likelihood algorithm. Idrisi Terrset software was used process the Landsat images by generating natural colour composite images which were then used to sample training sites. A stratified random sampling approach was employed which produced spectral signature files which were the basis for employing the Maximum Likelihood classifier to classify the images. Classified images were exported to ArcMap 10.7 where they underwent classification accuracy assessments. An error matrix approach was implemented, and the accuracy of the maps was assessed using the producer’s, user’s, overall and Kappa accuracy. Thereafter, LULC changes were quantified using ArcMap 10.7 by determining the area difference of each LULC type between 1990 and 2022. The SWAT models for the different resolution DEMs (i.e., 20m, 30m, and 90m) were set up on ArcSWAT, and the Swartkops catchment was delineated, subdivided into Hydrological Response Units, and run by inserting all the relevant input data such as LULC data (i.e., 1990, and 2022 classified maps), topographic data (i.e., the DEMs), soil data (i.e., FAO map), and weather data. Statistical evaluations for the performance rating of the models were conducted and incorporated the use of statistical parameters such as Nash-Sutcliffe Efficiency (NSE), Percentage of Bias (PBIAS), Coefficient of determination ((R2), and RMSE-Observation standard deviation ratio (RSR) for assessing the performance of each SWAT model. The model producing the most satisfactory performance was used to compute runoff conditions for the Swartkops catchment. Computations were conducted using the Soil Conservation Service (SCS) curve number method. Fieldwork, which incorporated measuring iii runoff for different LULC types using Gerlach troughs at hillslope scale, was conducted to validate the results of the SWAT model. Results indicated that the 1990 and 2022 LULC maps had an overall accuracy of 87.11% and 94.89%, respectively which was highly satisfactory. The Kappa statistics reflected similar results where the 1990 map had a value of 0.84 while the 2022 map had a value of 0.94, indicating high statistical agreement between the classified maps and the reference data. The study also found that bare areas exuberated the greatest area change with a decline of 9.49%, while built-up areas manifested the highest increase of 5.97% from 1990 to 2022. Agricultural land increased by 4.79% in conjunction with a slight increase of 0.44% by green vegetation while water declined by 1.71%. To determine the ideal DEM to analyse hydrological response, the LULC maps in conjunction with other input data were inserted into the SWAT model to assess model performance. It was found that the 30m produced satisfactory model performance (NSE = 0.49 at calibration and 0.67 at validation) and was eligible to assess runoff conditions as a function of LULC change. Other statistics indicated satisfactory model performance at calibration (PBIAS = 48.80, R2 = 0.51, RSR = 1.02) and validation stage (PBIAS = -38.1, R2 = 0.47, RSR = 1.08). The 90m DEM possessed the poorest model performance (NSE = 0.18 at calibration and 0.35 at validation) followed by the 20m DEM (NSE = 0.41 at calibration and 0.32 at validation). Runoff simulations using the 30m SWAT model showed that surface runoff was highest in areas where there were built-up areas. Built-up areas and bare areas yielded 36% of the total surface runoff individually, while vegetation produced only 28% in 1990. Similar readings were obtained for 2022, which included agricultural land that produced 29% of the surface runoff. Runoff volume measured at hillslope scale was highest in bare areas (6.6 L) and built-up areas (9.3 L). Therefore, this study shows that the resolution of DEMs must concur with the relevant scale of the study to produce optimal results. Additionally, this study showed that a change in LULC heavily affects the amount of surface runoff generated, which has several implications in terms of flooding. Therefore, this study is useful as it will inform sustainable catchment management decisions, and water resource management, and enhance our understanding of the relationships between DEM spatial resolution, LULC change, SWAT modelling, and water quantity calculations. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Effects of oxytocin treatment and calcium inhibition on hydrogen peroxide-induced oxidative changes in c8-b4 microglial cells

  • Authors: Khau, Kananelo Adele
  • Date: 2025-04
  • Subjects: Calcium -- Physiological effect , Microglia , Human Physiology
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75903 , vital:80062
  • Description: Oxidative stress is implicated in the aetiology of several diseases as it leads to the destruction of cellular structures. In the central nervous system (CNS), oxidative stress results in neurodegeneration and the development of diseases such as Alzheimer’s disease and Parkinson’s disease. Microglia play a crucial role in maintaining brain homeostasis. Of importance is the intracellular calcium regulatory activities that reinforce both microglia phenotype and functions, which are implicated in several neurodevelopmental disorders. Despite extensive literature about the neuroprotective role of oxytocin, its impact on microglial activity has not been studied and it remains unclear whether the underpinned molecular mechanism of action is calcium-dependent or not. Thus, this study aimed to study the effects of inhibited calcium channel and oxytocin treatment on microglial response to hydrogen peroxide (H2O2)- oxidative stress. Initially, the C8-B4 microglial cells were evaluated as valid constructs for the calcium inhibition and oxidative stress models. For the calcium inhibition model, the calcium channels were inhibited by treating the cells with 12.5 μM and 25 μM nickel chloride (NiCl2) for 24 and 48 hours. The intracellular calcium levels were measured using a calcium detection assay and the viability of the cells was determined using 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. For the oxidative stress model, the cells were treated with H2O2 for 1-4 hours to induce oxidative stress. The viability of the cells was measured, and markers of oxidative stress (malondialdehyde (MDA), glutathione (GSH), interleukin (IL) -6) were quantified. Once the treatments were validated, the cells were treated with 12.5 μM NiCl2 and 1000 nM oxytocin for 24 hours, followed by 0.5 mM H2O2 for 1 hour. The cell viability was measured, and markers of oxidative stress were quantified (IL-6, MDA, superoxide dismutase (SOD)). The study found that NiCl2 inhibited calcium channels in C8-B4 cells, thereby disrupting calcium homeostasis. There was a decrease in the levels of intracellular calcium levels and cell viability following treatment with NICl2. H2O2 induced oxidative stress and inflammation in the cells. This was demonstrated by increase in SOD and MDA activity, as well as a decrease in the levels of GSH. Inflammation was confirmed xii by an increase in the levels of IL-6. Disrupted calcium signalling exacerbates oxidative stress and diminishes the therapeutic efficacy of oxytocin against such stress. Conversely, when calcium signalling remains intact, oxytocin demonstrates a notable therapeutic effect against oxidative stress. In conclusion, the study adds to the existing literature and leads to an improved understanding of the importance of calcium homeostasis and the functions of microglial cells in the brain. The research findings also shed light on the potential use of oxytocin in the treatment of neurodegenerative disorders as well as other neurological disorders linked to oxidative stress. , Thesis (MSc) -- Faculty of Science, School of Biomolecular & Chemical Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Evaluating peptide conjugated gold nanoparticles as an anti-cancer treatment using HT29 cells

  • Authors: Basson, Deané
  • Date: 2025-04
  • Subjects: Colon (Anatomy) -- Cancer , Rectum -- Cancer , Nanotechnology
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/75479 , vital:79929
  • Description: Colorectal cancer (CRC) is a global health concern with rising incidence and mortality rates, with current treatments for advanced stages often limited by adverse effects and low specificity. The advancement of targeted nanotechnology offers a promising alternative. To investigate the efficacy of peptide-conjugated gold nanoparticles for the targeted treatment of CRC, c-AuNPs were synthesised using the Turkevich-Frens method and capped with various ligands to create BSA-AuNPs, PEG-AuNPs and p.14-PEG-AuNPs. The nanoparticles were characterised using UV–Vis spectroscopy (UV-Vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). The cytotoxic potential of the nanoparticles was evaluated using MTT, fluorescent microscopy and electron microscopy with a primary focus on p.14-PEG-AuNPs. PEG-AuNPs and BSA-AuNPs were included for comparative purposes, and 5-Fluorouracil (5-Fu) was used as the positive control. The results indicate successful synthesis and characterisation of BSA-AuNPs, PEG-AuNPs, and p.14-PEG-AuNPs with hydrodynamic sizes between 20 and 30 nm, and a core size of 14.455 ± 1.001 nm. Of the nanoparticles tested, p.14-PEG-AuNPs demonstrated the highest cytotoxicity. At 50 μg/mL, p.14-PEG-AuNPs reduced the cell viability to 59.83% ± 12.97%. Whereas a similar viability for PEG-AuNPs and BSA-AuNPs (56.64% ± 7.266% and 58.66% ± 0.517%) was only reached at much higher concentrations of 200 μg/mL and 150 μg/mL, respectively. Fluorescent microscopy analysis inferred that p.14-PEG-AuNPs and PEG-AuNPs treatments caused increased mitochondrial activity and chromatin condensation, which are common signs of apoptosis. Additionally, microscopy analysis of PEG-AuNPs treatment revealed morphological characteristics consistent with apoptosis. These findings demonstrate the therapeutic potential of p.14-PEG-AUNPs as an anticancer agent for the treatment of CRC. , Thesis (MSc) -- Faculty of Science, School of Life, Earth, Environmental & Agricultural Sciences Cluster, 2025
  • Full Text:
  • Date Issued: 2025-04

Evaluating the impact of water scarcity and factors influencing the adoption of climate-smart irrigation technologies on small-scale vegetable farmers in the Amathole District Municipality, Eastern Cape Province

  • Authors: Majola, Nelly Khanyisile
  • Date: 2025-04
  • Subjects: Farmers -- South Africa -- Eastern Cape , Farms, Small -- South Africa -- Eastern Cape , Vegetable gardening -- South Africa -- Eastern Cape
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76014 , vital:80106
  • Description: Small-scale vegetable farmers play a crucial role in terms of poverty alleviation, food security, employment and improvement of the standard of living in the rural areas. However, the climate change (CC) effects have caused unfavourable weather, such as higher temperatures and drought in many parts of the world. This effect has exacerbated the issue of water scarcity, especially in the semi-arid and arid areas like the Amathole District Municipality in the Eastern Cape Province. Thus, the study sought to evaluate the impact of water scarcity on small-scale vegetable farmer’s productivity, and the factors influencing the adoption of Climate-Smart Irrigation Technologies (CSITs) on small-scale vegetable farmers in the Amathole District Municipality in the Eastern Cape Province, South Africa. The study employed the quantitative research approach including semi-open-ended informant interview questionnaires. The study’s target population were small-scale vegetable farmers serviced by the Department of Rural Development and Agrarian Reform (DRDAR) in the Amathole District Municipality in the Eastern Cape Province (EC). Purposive and snowballing sampling techniques were employed to obtain a total of N=120 population of small-scale farmers actively practising vegetable production. The descriptive statistics were utilised to investigate demographic traits and the current water scarcity adaptation and coping strategies applied by the small-scale vegetable farmers. The findings revealed that 42% of small-scale vegetable farmers had no formal education, 35% had primary education, 20% of the small-scale farmers had secondary education and only 3% had attained college certificates. A Multivariate Analysis of Variance (MANOVA) was employed to assess the impact of water scarcity on the small-scale vegetable farmer’s productivity. The results revealed that the independent variable (Water Scarcity) was significant on the dependent variables with soil degradation showing (P> of 0.0046), poor crop quality (P>of 0.0003). However, other independent variables, such as pests and diseases and farming expansion were not significant. This may be the result as some small-scale farmers use drought-tolerantcultivars, crop rotation and others practice mulching to maintain soil moisture. The Multiple Linear Regression Model which was also utilised to examine the factors influencing the adoption of Climate-Smart Irrigation Technologies using multiple models, (model:1) revealed that high cost of Climate-Smart Irrigation Technologies with probability>f 0.0000 had an influence on small-scale farmers in adopting the (CSITs), (model:2) Low Income Consideration also showed a significant influence of Probability>f 0.000 and (model:3)Government Incentives with Probability>f 0.0022 limited access to government support incentives had an influence on the adoption of CSITs of small-scale vegetable farmers. To observe farmer’s perceptions on agricultural support service training intervention on irrigation water management, an Ordinary Least Square (OLS) was employed. The results indicated that lack of training on irrigation water management was significant P> 0.015 underscoring that lack of training support by the government has an influence regarding water conservation on the small-scale vegetable farmers. Thus, the need for the adoption of Climate-Smart Irrigation Technologies (CSITs) and training on irrigation water management is generally important to mitigate against the impact of water scarcity and improve water usage. Addressing the issue of water scarcity and promoting the adoption of Climate-Smart Irrigation Technologies, requires a comprehensive understanding of the specific impact on small-scale vegetable farmers and the underlying factors that hinder or facilitate their adoption. In addition, lack of training and awareness, government support incentives, funding, and access to credit have been identified to be some of the major factors influencing the adoption of technologies. Hence, it is crucial for government to provide training and awareness, especially on Climate-Smart Irrigation Technologies for small-scale vegetable farmers. Relevant training and information dissemination plays an important role in enhancing knowledge and improving small-scale farmers’ decision-making when it comes to technology adoption and water management. Therefore, the study recommended regular training and frequent engagement between the small-scale vegetable farmers and extension officers. There is a need for the implementation of agricultural programmes that will enhance the farmers’ skills and knowledge of good agricultural practices and innovative technology. Lastly, the initiation of financial support programmes and the provision of information on agricultural credit institutions must be easily available to all small-scale vegetable farmers. , Thesis (MSc) -- Faculty of Science, School of Natural Resource Science & Management, 2025
  • Full Text:
  • Date Issued: 2025-04

Extracting more ecologically-significant information from the southern Cape fossil pollen records: a reassessment of the Asteraceae pollen types

  • Authors: Nel, Luke Sean
  • Date: 2025-04
  • Subjects: Asters -- Africa, Southern -- Identification , Biodiversity -- South Africa , Pollen
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76133 , vital:80166
  • Description: It is no surprise that South Africa is home to three of the 35 biodiversity hotspots in the world, thanks to a rich species abundance and diversity, filling the South African landscape with 20 000 different plant species. The Cape Floristic Region (CFR) is one of the three biodiverse hotspots in South Africa, home to 9000 plant species, 1435 of which are on the Red Data List, with an endemism rate of 70%, making the CFR the pinnacle for conservation. The Asteraceae is the largest contributing plant family within the CFR, accounting for 986 species with equally diverse pollen morphological characteristics. However, when it comes to the palynological classification of Asteraceae pollen for the elucidation of palaeoecological information, it is often the case that the taxonomic resolution is not high enough. The majority of the Asteraceae that can be found within the palaeoarchives across South Africa yield no ecological information about the past vegetation. This study made use of a new morphological classification developed by Dr Saúl Manzano and Dr Nicola Bergh as part of an ongoing research initiative: COMPOSITAS-SA: COMpositae Pollen Study and Identification of Types for Applied Science in South Africa. The new morphological classification was applied to three palaeoarchives within the CFR, aimed at reclassifying and recounting existing fossil pollen material in order to extract more ecologically-significant information, and place this in context with the established literature available from the study sites and the overall region. This study was able to significantly contribute more morphological pollen types to the CFR and in doing so increase the representativeness of the Fynbos and Subtropical Thicket ecological groupings across the Rietvlei – Still Bay, Eilandvlei, and Baviaanskloof study sites. The Asteraceae that contributed the most as a single pollen type was the Osteospermum, accounting for 16% of the Subtropical Thickets relative percentage, followed by Stoebe and Metalasia contributing 8.4% and 5.7% respectively towards the Fynbos elements within the southern Cape. The Osteospermum pollen in this study does appear to behave differently to the traditional thicket pollen whereby favouring similar conditions to that of the Fynbos especially in the last 2000 cal yr BP. This is especially prominent in Rietvlei – Still Bay and Eilandvlei where the Osteospermum pollen relative percentages from the Subtropical Thicket mimics the Asteraceae pollen relative percentages of the Fynbos. IV This work advocates for the application of the new Asteraceae classifications to more study sites across South Africa in order to enhance palaeoenvironmental reconstructions and uncover the story of the Asteraceae. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04

Fischer-Clifford Theory Applied to Certain Maximal Subgroups Associated with the Simple Groups Fi22, Co1, F4(2), and the Monster M

  • Authors: Kapata, Langson
  • Date: 2025-04
  • Subjects: Clifford algebras , Maximal subgroups , Linear algebraic groups
  • Language: English
  • Type: Doctoral theses , text
  • Identifier: http://hdl.handle.net/10948/75892 , vital:80056
  • Description: Let G = P.G be a finite extension of a p-group P by a group G. Then the quotient group Q = G/K is constructed, where K ⊴ G is a characteristic subgroup of P. It is a well-known fact that the ordinary irreducible characters Irr(Q) of Q can be lifted to G. Therefore, it follows that a so-called Fischer-Clifford matrixM(g) of the quotient group Q is embedded in the corresponding Fischer-Clifford matrix M(g) of G. In this thesis, the Fischer-Clifford matrices method is used to construct the ordinary character table of extension groups G of nonabelian p-groups P. The powerful Fischer-Clifford matrices method was developed by Bernd Fischer to compute the ordinary character table of the p-local maximal subgroups of the Sporadic simple groups. This method was applied to many extensions of elementary abelian p groups. The method is more complicated when P is nonabelian and in this thesis we want to contribute to the Fischer-Clifford theory by presenting a method to deal with these types of extensions. The strategy followed in this thesis is to compute the Fischer-Clifford matrices M(g) of G from the corresponding Fischer-Clifford matricesM(g) of G modulo the Frattini subgroup Φ(P) of P , for each conjugacy class [g] of G. The method employed to construct the desired matrix M(g) of G from the matrixM(g) of the underlying quotient group Q is called the lifting of Fischer-Clifford matrices method. In this thesis, the lifting of Fischer-Clifford matrices method was applied to extensions of generalized extraspecial p-groups Cm p × 21+2n + which are maximal subgroups associated with the simple groups Fi22 and F4(2). As well as the ordinary character tables of the maximal subgroups 24+12·(S3×3.S6) and 72+1+2:GL2(7) of the sporadic simple groups Co1 and the Monster M, respectively, were constructed by the lifting of Fischer-Clifford matrices method. , Thesis (PhD) -- Faculty of Science, School of Computer Science, Mathematics, Physics and Statistics, 2025
  • Full Text:
  • Date Issued: 2025-04

Herbicide impacts on target and non-target vegetation in a forestry plantation and a fynbos environment, South Africa

  • Authors: Tzitzika, Ira
  • Date: 2025-04
  • Subjects: Herbicides -- Environmental aspects , Fynbos -- South Africa , Forests and forestry -- Economic aspects
  • Language: English
  • Type: Master's theses , text
  • Identifier: http://hdl.handle.net/10948/76207 , vital:80177
  • Description: In the commercial forestry sector, the management of competing vegetation ensures optimal tree growth, while in natural conservation areas, the primary objectives for reducing the occurrence of invasive species are to restore biological diversity, and/or to improve ecological functioning. Within the forestry sector, there has been a global shift to reduce the total amount of herbicide applied over a rotation. Similarly, with the increased awareness surrounding the negative ecological impacts of alien invasive trees in South Africa, there is little information available as to the effects the herbicides used for invasive control on existing and/or newly germinated non-targeted species in the immediate area to which they are applied. The main objective of this study was to determine the impacts of herbicides on target and non-target vegetation species within either a commercial forestry or natural/fynbos environment. Within the commercial pine forestry plantation, the aim was to determine the efficacy of alternative herbicides (pre-emergent, selective and desiccant herbicides), to reduce the reliance on manual ring-weeding and/or glyphosate (current practice) for vegetation management, and to determine if the total amount of active ingredient (a.i.) applied per hectare could be reduced through the use of these alternative herbicides, without negatively impacting tree performance. Within the invaded fynbos environment, the aim was to determine how effective current herbicide products are in terms of reducing targeted alien invasive species, and to determine the impacts of the herbicide used on the non-targeted species (fynbos), whether existing and/or newly germinated. The commercial forestry plantation and fynbos environment trials were situated in Lottering Plantation in the Eastern Cape, and Jonkersberg in the Western Cape (respectively). The commercial forestry trial, consisted of ten treatments, which were replicated three times and laid out in a Randomised Complete Block Design (RCBD). The treatments included a Weedy control, a Weedfree control, two pre-emergent herbicides (isoxaflutole and/or indaziflam), a desiccant herbicide (pelargonic acid), and selective post-emergent herbicides (clethodim and clopyralid as a tank-mix) respectively. Over the 735 days of the trial, vegetation cover assessments were carried out, tree performance and phytotoxicity were measured, and the timing frequency and quantity of herbicide applied per treatment recorded after each spraying event. These variables, in addition to the environmental impact of each active ingredient, were used to determine overall treatment efficacy for implementation. For the invaded fynbos trial, three different sites (but with similar physiographic and climatic characteristics) were selected based on the occurrence of a dominant invasive species (pine, wattle and/or eucalypt). A similar experimental layout was used for this study as is used within agriculture research, where the same treatments are tested across a range of sites (which allows for the determination of any site  treatment interactions). On each site, seven treatments were implemented, which included an Untreated control (invasives remain), a Manual control (invasives manually cut), and five herbicide treatments (Imazapyr, Glyphosate, Picloram, Triclopyr and Metsulfuron-methyl) that were applied to the invasive vegetation after manual clearing. Ten quadrats were laid out within each treatment plot, within which the vegetation was assessed. The trial took place over 259 days, where vegetation cover assessments were carried out, species abundance determined, the volume of herbicide and quantity of a.i. applied and the surface area of the treated cut-stumps calculated, herbicide bioassays conducted, and the environmental impact of the active ingredients considered to determine the overall efficacy of the herbicide treatments. In comparison to the Weedy control treatment in the commercial forestry trial, vegetation occurrence was reduced and tree performance was significantly improved in all herbicide treatments. Of the herbicides tested, the pre-emergent treatments (indaziflam and isoxaflutole) demonstrated effective and long-term suppression of the target vegetation, but with the sedges and ferns not as well controlled as the other vegetation types. Although the selective treatment (clethodim and clopyralid) was effective in terms of the control of younger vegetation types, they were not as effective on the woody perennials. Some phytotoxicity symptoms were observed with pelargonic acid (necrosis where the herbicide came into contact with the needles), clethodim and clopyralid (discoloration and abnormal needle growth, and indaziflam (chlorosis), but this was transient, and did not have an impact on overall tree performance. The environmental fate of indaziflam and clopyralid indicates potential soil persistence, emphasizing the need for cautious application in sensitive ecosystems. This study demonstrated the viability of selective and pre-emergent herbicides as alternatives to glyphosate for the management of vegetation, with the pre-emergent herbicides resulting in an overall reduction in the total a.i. used to achieve this control. Compared to the Untreated control in the invaded fynbos trial, all treatments where the invasives were cut improved both growth in terms of non-target vegetation diversity and abundance. Resprouting of stumps occurred in the Manual control, whereas all five herbicide treatments were effective in terms of killing the invasives when applied as cut-stump application within 20 minutes of cutting. Although there was an initial decrease in vegetation (as a result of disturbance associated with invasive clearing operations), this was followed by an initial increase in cover of the faster growing grasses and broadleaves (ability to respond rapidly to disturbance), and the fynbos vegetation over time. In terms of new invasive regrowth, Picloram, Triclopyr, and Glyphosate were effective for managing invasive pine, Metsulfuron-methyl, Picloram and Imazapyr where more effective for managing wattle, while Metsulfuron-methyl performed marginally better for controlling eucalypts. In addition, no impact from run-off, spray drift or residual herbicide activity (release from decaying invasive roots that were treated) was detected based on the herbicide bioassay in combination with the vegetation assessments. As this study was limited to one environment with a unique vegetation community and soil type, it is recommended to conduct further studies on sites with different vegetation communities, soil types, hydrology, and invasive species interactions. Although herbicides have proven successful for the control of targeted vegetation in in both commercial plantations and natural areas in South Africa, their use may also have adverse, unintended impacts on the non-targeted species that are inadvertently exposed. Both the forestry and fynbos trials were effective in terms of fulfilling their objectives, and also highlighted the need for a more holistic approach when deciding upon the most appropriate management approach. For example, the development of a more comprehensive decision-support system that will include the environmental impacts of any chosen herbicide, the impacts on non-target vegetation, off-site impacts, as well as the development of alternative methods of control. , Thesis (MSc) -- Faculty of Science, School of Environmental Sciences, 2025
  • Full Text:
  • Date Issued: 2025-04
  • Disclaimer
  • Privacy
  • Copyright
  • Contact