RU sleepy? - sleep/wake characteristics and sleep quality among undergraduate students attending Rhodes University
- Authors: Young, Celine Brittany
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464776 , vital:76544
- Description: Background: University students, specifically older adolescents and young adults, are at high risk of insufficient and poor-quality sleep due to age-related biological changes converging with several systemic factors unique to the university context. These include but are not limited to freedom and independence, communal living environments, academic demands and associated stress, erratic schedules, and high technology use. While there has been extensive research on sleep quality in students in other parts of the world, there has been comparatively less in South Africa, which may present unique contextual influencing factors. Thus, this study aimed to characterise sleep/wake characteristics and sleep quality in a sample of undergraduate students attending a South African University. Additionally, the study aimed to determine the impact of certain demographic factors on sleep quality in the students. Lastly, the current study aimed to determine what factors may influence the students' sleep quality. Method: This study adopted a cross-sectional design and explored sleep quality and sleep/wake characteristics (e.g., bedtimes, rise times, sleep duration, sleep latency, etc.) through an online survey circulated amongst undergraduate students via Rhodes university email platforms and student social media pages. The testing period started on 15 August 2022 and continued until 8 October 2022. The survey consisted of three main sections: (1) socio-demographic factors; (2) the Pittsburgh Sleep Quality Index (PSQI); (3) an open-ended question that asked students to comment on the factors which they felt may be influencing their sleep over the previous month. Results: 393 students participated in this study, which corresponds to a response rate of 6.30%. The results revealed notable levels of poor sleep quality (mean global score of 9.79 (±3.36)) and a high prevalence of poor sleepers within the whole sample (over 90%), as well as across different demographic groups. Analysis indicated poor overall sleep quality, and concerning sleep/wake characteristics, such as, bedtimes, rise times, sleep latency, time in bed, habitual sleep efficiency, sleep duration, etc. Additionally, participants reported extended sleep latencies and difficulties initiating sleep within 30 minutes. Daytime dysfunction was prominent, indicating challenges in daily functioning. Demographic comparisons revealed that male students generally reported better subjective sleep quality and lower global PSQI scores than female students, with 2 females presenting with poorer sleep quality overall. Students living in university residences reported significantly later bedtimes and shorter sleep durations than off- campus students. Regarding year of study, third-year students reported better subjective sleep quality, longer times in bed, longer sleep durations and overall better sleep quality than first- and second-year students. Regarding funding mechanisms, students on the National Students Financial Aid Scheme had significantly higher subjective sleep quality scores but later bedtimes than students in the "other" funding groups. Thematic analysis revealed that several self-reported factors impacted student sleep negatively. Mental health issues were the most commonly cited theme (26.72% of students), which included anxiety, stress, worry, and overthinking. University-related factors were the second most frequently cited theme (25.49% encompassing academics, funding, and navigating university life). Environmental influences comprised of issues with noise, particularly in university residences, weather, and lighting. Discussion: In sum, the results of this study indicate that in this sample, the drivers of poor sleep quality seemed to be late bedtimes, early rise times, prolonged sleep latency, frequent night awakenings, and overall short sleep duration, all of which were driven by several systemic factors. These findings underscore the importance of assessing sleep health beyond just sleep duration and indicate compromised sleep health within this population, evidenced by high levels of daytime dysfunction due to inadequate and poor-quality sleep. The challenges faced by university students extend across various aspects of their lives, including sleep health, with poor sleep quality and insufficient sleep having significant implications for academic performance, mental health, and overall well-being as they transition into adulthood. , Thesis (MSc) -- Faculty of Science, Human Kinetics and Ergonomics, 2024
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- Date Issued: 2024-10-11
Screening and characterisation of novel compounds and their derivatives from South African medicinal plants against triple negative breast cancer cells
- Authors: Nyemba, Getrude Rutendo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463952 , vital:76460
- Description: Access restricted. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
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- Date Issued: 2024-10-11
Search for acrylonitrile-based inhibitors of SAR-Cov-19 main and papain-like proteases through covalent docking and high-throughput virtual screening
- Authors: Ntantiso, Yamkela
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463941 , vital:76459
- Description: The sudden outbreak of SARS-CoV-2 formerly known as the 2019 novel coronavirus (2019-nCoV) quickly turned into a pandemic of coronavirus disease 2019 (COVID-19), the scale of which has never been seen before. High infection rates and mortality from COVID-19 placed pressure on global health services, and this has been to the detriment of the global economy. However, treatment options for COVID-19 are still very limited; hence, it is now as important as ever that researchers explore searching for new compounds with pharmacokinetic properties that inhibit the two COVID proteases - the main protease (Mpro) and the papain-like protease (PLpro). The main protease is a cysteine protease; as such, it is susceptible to permanent inhibition by reactive species (warheads) that may covalently bind to cysteine residues. One such class of compounds is acrylonitriles, in which the reactive acrylonitrile is reactive towards cysteine through a Michael addition reaction. The resulting covalent interaction is permanent and inactivates the cysteine residue and hence the protease within the context of the COVID-19 life-cycle. In this context, this study seeks to utilize computational-based approaches to identify acrylonitrile-based inhibitors of coronavirus drug targets. To do this, the ZINC database has been screened for compounds containing acrylonitrile functionality, due to its known nature as a warhead that binds to cysteine residues. Pharmacokinetic properties are computed to evaluate the viability of identified inhibitors, and covalent and non-covalent molecular docking approaches to the Mpro enzyme crystal structure have also been used to assess the identified systems. To gather more information and evaluate the most promising systems, a subset of the most promising compounds have been subjected to molecular dynamics simulation (for both covalently bound and non-covalently bound systems). , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
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- Date Issued: 2024-10-11
SolarKAT: a solar imaging pipeline for MeerKAT
- Authors: Samboco, Victória da Graça Gilberto
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465102 , vital:76573
- Description: Solar interference poses a significant challenge in radio interferometric observations, particularly with the increasing sensitivity of modern new-generation telescopes. This thesis presents the SolarKAT pipeline, a novel approach designed to mitigate solar interference in MeerKAT observations. The pipeline incorporates a series of steps, including self-calibration (second generation calibration or 2GC), precise determination of the Sun’s position, phase centre adjustments, creation of region-based masks, deconvolution, prediction, solar model subtraction, and peeling. We applied the SolarKAT pipeline to three datasets that feature the Sun in different conditions (frequency band and angular distance from the Sun to the telescope pointing position). These observations were obtained from three MeerKAT telescope surveys: ThunderKAT, MIGHTEE and LADUMA. We compared the visual images, peak fluxes, flux density, RMS and pixel distribution to evaluate the pipeline. Our results showed a notable reduction in solar interference. This is evidenced by the improved image quality, reduction in RMS and pixel distribution values, and consistent peak flux measurements after applying the pipeline. SolarKAT has not only improved the data quality but also demonstrated to be a valuable tool in producing high-quality solar images, which can be a helpful resource for solar physics and space weather forecasts. This study showcases the potential of the SolarKAT pipeline in enabling high-quality radio interferometric observations, even in the presence of solar interference. Unlike conventional methods that often discard corrupted visibilities (e.g. flagging), our approach focuses on recovering them. Additionally, the SolarKAT pipeline naturally delivers detailed images of the Sun. Our findings contribute to advancing the field of radio interferometry, providing a valuable tool for researchers seeking to enhance the accuracy of their observations and conduct studies in solar physics and space weather. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
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- Date Issued: 2024-10-11
South Africa’s financial services trade and trade potential under the African Continental Free Trade Area
- Authors: Gyan, Mawuko
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462846 , vital:76340
- Description: This study investigates the nature, importance and prospects for growth of South Africa’s trade in financial services and trade potential under the African Continental Free Trade Area (AfCFTA) Agreement. It does so by identifying and measuring the share, growth performance and some of the characteristics of South Africa’s financial services trade in the aggregate and with selected trading partners and regions. It also computes South Africa’s trade potential in financial and finance-related services trade with selected African trading partners amid the ongoing AfCFTA services trade negotiations, using trade complementarity indices (TCIs). Finally, the study estimates the effect of regional trade agreement participation on bilateral financial services trade involving African economies using a gravity model. The study employs the use of descriptive trade statistics to analyse the share and growth performance of South Africa’s services trade in the aggregate and at the sub-sector level, based on balance of payments (BOP) data for the years 2005 to 2022 from the ITC, UNCTAD and WTO Trade in Services Database. Bilateral trade data from the OECD and WTO BaTIS Database is also used in the analysis of intra-African trade. In order to investigate trade through Mode 3, information on FDI statistics is sourced from recent reports. Through analysing trade complementarity indices (TCIs), the study finds that South Africa has significant potential to increase exports of financial and finance-related services to Mauritius, Ghana and the SADC and non-TFTA regions. South Africa has significant import TCIs with the COMESA and non- TFTA regions as well as Egypt, Tunisia and Kenya. The gravity model estimation reveals that membership in African regional groupings like the AfCFTA, SADC, COMESA and the EAC have no significant positive impact as yet on intra-African financial services trade. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
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- Date Issued: 2024-10-11
Spatial pattern analysis of thicket expansion in a semi-arid savanna
- Authors: Putzier, Rachel Rayne
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464484 , vital:76515
- Description: Woody thickening has negative economic and ecological impacts in savannas globally. While the increase of savanna trees as a form of bush encroachment has been well studied, less is known about the increase of thicket species in savannas, which is an important phenomenon resulting in the formation of closed-canopy clumps which may exclude the grass layer over time. The early stage of thicket expansion is often initiated by a nucleating savanna species which facilitates the establishment of woody thicket pioneer species, and as the thicket clump formation expands, bush clumps increase in dominance, thereby increasing the frequency of competitive interactions and leading to a possible switch from facilitative to competitive interactions. Spatial point pattern analysis provides a useful tool to elucidate these underlying patterns and ecological processes. I used high resolution LiDAR data combined with spatial point pattern analysis to understand tree-tree interactions in a semi-arid savanna in the Eastern Cape Province of South Africa. I conducted a cluster analysis based on vegetation structural variables to distinguish different stages of woody plant encroachment from open savanna to closed canopy thicket. Using the canopy height model, I quantified the change in the grass height from open savanna to closed canopy thicket clumps as an indicator of a possible biome shift. Additionally, I used spatial point pattern analyses to investigate the effect of thicket clump formation on the composition of savanna and thicket species, the overall patterns of trees, and the associations of small thicket species with large Vachellia karroo trees, which serve as clump initiators. Finally, I examined the mortality of savanna trees across increasing stages of thicket expansion using second order spatial statistics, namely the Mark- and Pair-Correlation Functions. Results confirmed that three vegetation states, influenced by elevation, are present at the study site, representing open canopy savanna (early-stage thicket encroachment), encroached savanna with low thicket dominance (intermediate-stage thicket encroachment), and highly encroached with dominant thicket clumps (late-stage thicket encroachment). These stages showed increasing tree height, canopy cover and canopy height density, as well as decreased (but not completely absent grass layer) as thicket encroachment progresses. Spatial point pattern analysis showed, as predicted, that there was an overall aggregation of trees at small-scales within early thicket clump formation, from which I inferred that facilitative relationships may exist between trees. Contrary to my predictions, at later stages of thicket clump formation I found dominant independent patterns between savanna adults and juvenile thicket species, which may result from a combination of facilitative and competitive effects. Lastly, as expected, I found that the density of V. karroo mortality increased as thicket encroachment increased, with an overall random spatial pattern of dead V. karroo across encroachment stages. As predicted, tree mortality was randomly distributed in space in the open savanna state, and as thicket clump formation increases, tree competitive mortality became more evident, as well as decreased tree performance. Overall, the study highlights the interplay between facilitation and competition in semiarid savanna where thicket clumps are expanding. Intervention strategies are suggested to target areas of intermediate thicket clump formation, as these areas provide an opportunity to remove V. karroo before the nucleation process has enabled the establishment and increase of thicket species and to ensure the grass layer is kept productive. I conclude that the use of remote sensing and LiDAR technology holds a wide range of possibilities for monitoring and managing woody encroachment in savanna systems, however these methods need to be further refined for effective use within African savanna and thicket context, which displays high spatial aggregation making typical segmentation methods difficult. , Thesis (MSc) -- Faculty of Science, Botany, 2024
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- Date Issued: 2024-10-11
Statistical classification, an application to credit default
- Authors: Sikhakhane, Anele Gcina
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465069 , vital:76570
- Description: Statistical learning has been used in both industry and academia to create credit scoring models. These models are used to predict who might default on their loan repayments, thus minimizing the risk financial institutions face. In this study six traditional and one more recent classifier, namely kNN, LDA, CART, RF, AdaBoost, XGBoost and SynBoost were used to predict who might default on their loans. The data set used in this study was imbalanced thus sampling and performance evaluation techniques were investigated and used to balance the class distribution and assess the classifiers performance. In addition to the standard variables and data set, new variables called synthetic variables and synthetic data sets were produced, investigated and used to predict who might default on their loans. This study found that the synthetic data set had strong predictive power and sampling methods negatively affected the classifiers performance. The best-performing classifier was XGBoost, with an AUC score of 0.7732. , Thesis (MSc) -- Faculty of Science, Statistics, 2024
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- Date Issued: 2024-10-11
Suspicious sctivity reports: Enhancing the detection of terrorist financing and suspicious transactions in migrant remittances
- Authors: Mbiva, Stanley Munamato
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/465058 , vital:76569
- Description: Migrant remittances have become an important factor in poverty alleviation and microeconomic development in low-income nations. Global migrant remittances are expected to exceed US $630 billion by 2023, according to the World Bank. In addition to offering an alternate source of income that supplements the recipient’s household earnings, they are less likely to be affected by global economic downturns, ensuring stability and a consistent stream of revenue. However, the ease of global migrant remittance financial transfers has attracted the risk of being abused by terrorist organizations to quickly move and conceal operating cash, hence facilitating terrorist financing. This study aims to develop an unsupervised machine-learning model capable of detecting suspicious financial transactions associated with terrorist financing in migrant remittances. The data used in this study came from a World Bank survey of migrant remitters in Belgium. To understand the natural structures and grouping in the dataset, agglomerative hierarchical clustering and k-prototype clustering techniques were employed. This established the number of clusters present in the dataset making it possible to compare individual migrant remittances in the dataset with their peers. A Structural Equation Model (SEM) and an Local Outlier Factor - Isolation Forest (LOF-IF) algorithm were applied to analyze and detect suspicious transactions in the dataset. A traditional Rule-Based Method (RBM) was also created as a benchmark algorithm that evaluates model performance. The results show that the SEM model classifies a significantly high number of transactions as suspicious, making it prone to detecting false positives. Finally, the study applied the proposed ensemble outlier detection model to detect suspicious transactions in the same data set. The proposed ensemble model utilized an Isolation Forest (IF) for pruning and a Local Outlier Factor (LOF) to detect local outliers. The model performed exceptionally well, being able to detect over 90% of suspicious transactions in the testing data set during model cross-validation. , Thesis (MSc) -- Faculty of Science, Statistics, 2024
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- Date Issued: 2024-10-11
Synthesis and biological evaluation of simple carboxylated chalcone and aurone derivatives
- Authors: Shauri, Thierry Lwanzo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464576 , vital:76523
- Description: Restricted access. Expected release in 2026. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
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- Date Issued: 2024-10-11
Teaching problem solving: the "Ten Commandments" approach
- Authors: Matiwane, Noluvuyo
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464897 , vital:76555
- Description: The evident need for an intervention to help physics students, especially incoming university students, develop their problem-solving skills led to exploring possible curriculum structures to achieve the goal. A modified curriculum structure of the first-year physics course, including explicit teaching of physics problem solving, was developed and implemented at Rhodes University, South Africa, in 2017. First-year physics students learn to solve problems by implementing the "Ten Commandments" of physics problem solving in their solutions, following a three-stage problem-solving framework. Additionally, students attend whiteboard tutorial sessions where they actively practise using the problem-solving framework in their solutions to physics problems with peers in an environment where help is available. Students are explicitly prompted to use the \Ten Commandments" during the whiteboard tutorials and not prompted for other assessment tasks. Students' solutions to formative physics assessment tasks (problem sets and tests) in the first semester were examined, problem-solving scores were determined using a problem-solving rubric developed in the department, shifts in attitudes and beliefs about physics and solving problems in physics were measured, and relationships between their problem-solving scores and task performance were evaluated to investigate how students adopted the framework and its implications over one semester. The problems issued to students differed in context and difficulty level; as a result, not all of the "Ten Commandments" were applicable to solve all problems, and different combinations of the commandments were applied to different problems. The explicit use of the problem-solving rubric to mark student problem sets was an indirect prompt for students to use commandments when doing their problem sets. As a result, students attempted to implement more applicable "commandments" (mostly partially correct) in their solutions to problem sets than in tests. Moreover, students' solutions to problems show that they used more of the "commandments" they were familiar with from school and less of the new ones, such as drawing diagrams without being prompted, producing algebraic solutions before substituting numbers, and doing dimensional analysis. Problem sets are often assumed to help prepare students for tests; however, correlations between students' problem-solving scores and performance between the two assessments did not give clear indications of whether problem sets were helping to prepare students to solve problems. Lastly, students' attitudes and beliefs also show a negative shift in students' perceptions of problem-solving by the end of the first semester. Problem-solving is a skill that develops in stages and over time; therefore, a timeframe longer than one semester is needed to report on significant changes in students' problem-solving habits and perspectives about problem-solving in physics. The study results are also important in giving insights into the initial developments of problem-solving skills and teaching problem solving. , Thesis (MSc) -- Faculty of Science, Physics and Electronics, 2024
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- Date Issued: 2024-10-11
The art of adaption: the National Arts Festival’s strategic response to the COVID-19 pandemic
- Authors: Brody, Blake Benjamin
- Date: 2024-10-11
- Subjects: Standard Bank National Arts Festival , Strategic planning , Strategic thinking , Crisis management South Africa , Business model , Stakeholder management , COVID-19 Pandemic, 2020- Influence
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/461863 , vital:76246
- Description: The National Arts Festival (NAF), an annual event held in South Africa, faced a significant challenge in 2020 due to the COVID-19 pandemic. The traditional in-person format of the festival was no longer feasible due to government restrictions. In response, the NAF's CEO, Monica Newton, led her team in a rapid transition to a virtual platform. This decision-making process and the creation of the first virtual NAF (vNAF) occurred within a remarkably short period of 100 days. This teaching case study delves into the academic framework of crisis management, stakeholder theory, strategic thinking, strategic management, and business models, examining their application in the context of the NAF's transformation. To understand the decision-making process and challenges faced by the NAF, a qualitative research design was employed. Data collection involved two face-to-face interviews with Monica Newton, CEO of the NAF, and secondary sources. The teaching case is accompanied by a comprehensive note for educators, offering guidance on its classroom use. The note includes a case synopsis, intended audience, suggested learning outcomes, theoretical connections, teaching strategies, potential discussion questions, evaluation methods, and additional resources. It supports a multi-faceted analysis of the NAF's transformation and encourages vibrant class discussion. , Thesis (MBA) -- Faculty of Commerce, Rhodes Business School, 2024
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- Date Issued: 2024-10-11
The assessment of abandoned cultivated lands: a case study of Lower Tsitsana and Hlankomo villages in the Tsitsa River catchment, Eastern Cape, South Africa
- Authors: Dakie, Regina Nokufa
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464787 , vital:76545
- Description: Globally, agriculture is an essential part of people’s livelihoods, contributing to rural economies and food security. However, cultivated land abandonment, the intentional or unintentional cessation of agricultural activities for takeover by other land uses, is becoming increasingly common. Although widely studied, the outcomes of cultivated land abandonment are highly context-dependent and varied. Understanding this phenomenon would thus benefit from placed-based social-ecological case study perspectives, particularly in more understudied contexts. This study represents such a perspective, taking a social-ecological approach to understand how land abandonment has emerged and what its consequences are for the desired future outcomes in the Hlankomo and Lower Tsitsana villages in the Tsitsa River catchment. Drawing on McGinnis & Ostrom’s (2009) framework, I framed cultivated land abandonment in my study area as a “focal action situation” informed by the interaction of natural resource systems, governance systems, actors, and resource units. To better understand the current state of the natural resource system and important ecological (resource) units (grass), I used two measures of ecological condition: a rapid assessment test that provided a broad, if superficial, understanding of degradation and land condition, and a veld condition assessment that provided an understanding of grassland composition and quality in abandoned fields. I also used aerial photographs to assess the extent of changes in abandoned cultivation in the catchment. To understand actors, governance systems, how they interacted with natural resource systems and units for land abandonment to emerge, and what implications these interactions may have for the future of these lands, I used semi-structured interviews. The Rapid Assessment Test tool showed that the abandoned cultivated fields were dominated by grasses (58.3%), while shrubs (11%) and succulents (11%) were the least prevalent. The veld assessment identified sixteen grass species in both villages, with Aristida junciformis (23%) and Eragrostis plana (22.2 %) being the most dominant. The grazing statuses of the grasses showed that there were more Increaser II species, followed by Increaser III, Exotic, Increaser I and Decreaser species, respectively. There were more grass species with low grazing and average grazing values than grass species with high grazing values. The Rapid Assessment tool and the Veld assessment showed that the fields were dominated by poor grass species that grow on degraded lands. The results thus showed that the abandoned cultivated lands are degraded and in poor condition, as they are covered mainly by poor grass species that are dominant in over-utilised and overgrazed areas. The aerial photographs showed a decline in cultivated lands from 1966 to 2015, with a significant decline between 1966 and 2003. The land under cultivation between 1966 and 2003 decreased by 95 %, resulting in an annual decline of 2.56 %. The land under cultivation from 2003 and 2015 decreased by 60 %, resulting in a decline of 4 % per year. Local people corroborated the increase in cultivated land abandonment in the interviews, and this is why I attempt to understand why abandoned cultivated land happened (how the resource system and governance systems/actors interacted to shape cultivated land abandonment). As in other South African rural contexts, reasons people gave for land cultivation abandonment revealed the strongly intertwined nature of ecological and social systems, including no fence, livestock eating crops, no cattle, lack of labour, migration, lack of resources (money and equipment), parents passing on, expensive fertilizers, rainfall variability, dependency on grants, lack of interest and laziness. People had different views about the future of the abandoned cultivated lands, suggesting building homes, recreational parks, poultry farms, and recultivating and livestock protection camps, while others indicated that they didn’t care what happens to the abandoned fields. Many people still value abandoned lands and would prefer for the land to be recultivated, but they are held back by factors beyond their control, such as no fencing and a lack of governmental support in the form of fertilisers and machinery for ploughing. Additionally, our ecological results suggest that, due to the degraded states of these lands, significant rehabilitation would be required to realize these desired outcomes. Overall, this study shows the social-ecological complexity that drives cultivated land abandonment in the Tsitsa River catchment, providing a context-specific understanding of the drivers and consequences of abandoned cultivated land, future options more specific to these villages, and the broader Tsitsa catchment. At the same time, my study also corroborates similar studies in rural African and other global South contexts, thus supporting generalizable knowledge that can be used in the development of agrarian, social and environmental policies in these regions. , Thesis (MSc) -- Faculty of Science, Environmental Science, 2024
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- Date Issued: 2024-10-11
The development of mobile money services and financial inclusion in Zimbabwe
- Authors: Chingono, Kudzaishe Emily
- Date: 2024-10-11
- Subjects: Mobile commerce Zimbabwe , Financial inclusion , Automated tellers , Financial literacy , Education Social aspects South Africa , Technology and older people South Africa
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462691 , vital:76326
- Description: Purpose- The use of mobile phones in Zimbabwe fostered the development of various financial innovations, such as mobile money services. It is important to note that the use of mobile money services in Zimbabwe has gradually increased. This study was carried out to determine the relationship between the development of mobile money services and financial inclusion in Zimbabwe. The main goal was to determine if there is a correlation between financial inclusion and the development of mobile money services. Design and Methodological approach: This study used a quantitative research design in which time series data was used to generate the analysis. The data used in the study covered a period of 20 years, starting from 2000 to 2020 on a yearly basis. Auto Regressive Distributed Lag (ARDL) Model was used to analyze the relationship. Findings: The ARDL study results showed that in the long run, there is no statistically significant correlation between the development of mobile money services and financial inclusion, and this is suggested by the long-term relationship between the two variables over a period of 20 years. In the short run, the study findings showed that the development of mobile money services have a positive significant influence on financial inclusion with. Therefore, increase in mobile money usage was associated with increase in financial inclusion. Between the period 2000 and 2020, the major determinants of mobile moneys services are age, number of ATMs, financial literacy, income level and mobile phone penetration. The tests also showed that these variables significantly and positively influenced use of mobile money as a financial inclusion tool in Zimbabwe (p<.05). Research Limitations: The study did not find a lot of current relevant literature that would explain the relationship between mobile money services and financial inclusion. Majority of the work was carried out in other countries, and little was covered in Zimbabwe. Practical Implications: The study results implies that government should put in place measure to ensure the expansion of mobile money services in the rural areas. The mobile telecommunication firms should ensure increased mobile phone penetration. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
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- Date Issued: 2024-10-11
The dynamics of novice and experienced Namibian teachers’ adoption of the Advanced Subsidiary Agricultural Science curriculum
- Authors: Nanyemba, Wilhelmina
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463581 , vital:76422
- Description: Access restricted. Expected release date 2026. , Thesis (MEd) -- Faculty of Education, Secondary and Post-School Education, 2024
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- Date Issued: 2024-10-11
The effect of an alkyl chain and β-diketonato-metal moiety on the photochromic behaviour of azobenzene compounds as materials for solar thermal fuels
- Authors: Bokhe, Witness Londi
- Date: 2024-10-11
- Subjects: Photochemistry , Isomerization , Solar thermal energy , Solar thermal fuel , Liquid crystals , Optical materials
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464510 , vital:76517
- Description: Scientists have been studying the development of renewable energy technologies in detail to create a sustainable energy supply. Among many new advanced material classes being researched recently are photo functional and photo responsive materials. These classes include azobenzene derivatives which are characterized by azo linkage (N=N) sandwiched by two phenyl rings. The trans-to-cis isomerization of azobenzene is a highly efficient and reversible process, making it an ideal candidate for solar thermal energy storage. This research investigates the impact of alkyl chain modifications and the incorporation of a β-diketonato-copper(II) complex on azobenzene derivatives, aiming to optimize their performance as efficient components in solar thermal fuel cells (STFs). The study focuses on a comprehensive analysis of these materials' ability to capture, convert, store, and release solar energy for enhanced sustainability in renewable energy applications. Experimental methodologies include synthesis of azobenzene derivatives with varying alkyl chain length, n (where n =8 & 10) and coordination of these compounds with a β-diketonato-copper(II) complex. Standard analytical techniques such as Nuclear Magnetic Resonance (1H and 13C NMR), Fourier Transform Infrared Spectroscopy (FTIR) and Ultraviolet/visible spectroscopy (UV/vis) were employed for chemical analysis of the synthesized material. Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Polarised Optical Microscope (POM) were used to study the thermal properties and morphology. The photostationery states were determined using NMR spectroscopy and the kinetic parameters of the cis-to-trans relaxation process determined by a UV spectroscopy study. The cis-to-trans isomerisation had a longer half-life than the trans-to-cis isomerisation. The band gap of the isomers is within the range of semiconducting inorganic materials. DSC and POM thermograms showed that the compounds are liquid crystalline. Finally, the study reports that the synthesised azobenzene derivatives show potential as material for solar thermal fuel cells because of their photo-isomerization ability. Furthermore, the synthesised compounds contribute to the advancement of sustainable and efficient solar energy utilization technologies, addressing the growing demand for clean energy solutions in the face of global environmental challenges. Because solar energy may be stored and used without causing direct emissions or pollution, they are considered clean energy. If solar thermal fuels fulfil sustainability standards, they may qualify as green energy. This entails minimising adverse effects on the environment, using non-toxic chemicals and procedures. , Thesis (MSc) -- Faculty of Science, Chemistry, 2024
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- Date Issued: 2024-10-11
The effect of biological control on the population dynamics of Pontederia crassipes Mart. (Pontederiaceae) and Salvinia minima Baker (Salviniales: Salviniaceae)
- Authors: Chikodza, Tressia
- Date: 2024-10-11
- Subjects: Pontederia crassipes , Salvinia minima , Pontederiaceae Biological control South Africa , Salviniaceae Biological control South Africa , Population dynamics , Secondary invasion
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/464462 , vital:76513
- Description: Pontederia crassipes is widely regarded as the most damaging floating aquatic weed in terms of its invasive traits, and its impact on aquatic ecosystems. Biological control using host-specific natural enemies is widely used for its control, with the most recent agent released being a planthopper, Megamelus scutellaris, in South Africa and the USA. In South Africa, inundative releases of M. scutellaris have been shown to control the weed even at eutrophic, and high elevation cold sites, such as Hartbeespoort Dam, arguably Africa’s most hypertrophic impoundment. However, subsequent to the control of P. crassipes on Hartbeespoort Dam, in 2021, a secondary invader, Salvinia minima, dominated the water system. Salvinia minima is only known from a handful sites near Hartbeespoort Dam and there is currently no approved biocontrol agent for it. The population dynamics of P. crassipes and S. minima at the Dam were overall interchanging due to insect feeding on M. scutellaris reducing P. crassipes populations thus allowing S. minima to become dominant. Intense feeding from M. scutellaris resulted in the reduction of P. crassipes populations. During late autumn and winter, remaining P. crassipes plants experienced frost damage from cold temperatures. The decrease in P. crassipes allowed S. minima to successfully invade, potentially as the result of less competition from P. crassipes, and therefore available resources, such as space, nutrients, and light. However, as spring approached, P. crassipes regenerated from its seed bank, and S. minima populations diminished. The changes in dominance were observed in 2021 and 2022 but in 2023, this trend was not evident as S. minima did not dominate as in previous years. This thesis investigated the combination of competition and herbivory by M. scutellaris on the vigour of P. crassipes and S. minima to understand the dynamics of these two highly invasive species. Competitive abilities of P. crassipes and S. minima were determined using an inverse linear model with plant weight as the yield variable. In the absence of herbivory, P. crassipes, was 4 times more competitive than S. minima, but as competitive when exposed to M. scutellaris feeding. Salvinia minima was 1.2 times as aggressive as P. crassipes in the absence of herbivory, but 2.6 times as competitive when M. scutellaris was established on P. crassipes. In the presence of herbivory on P. crassipes, interspecific competition coefficients from P. crassipes on S. minima were no longer statistically significant. These results indicate that the competitive ability of P. crassipes was reduced through herbivory when grown with S. minima, explaining the temporal dominance between the two species at Hartbeespoort Dam. Some studies have reported that P. crassipes releases allelochemicals as a competitive strategy to algae and phytoplankton. Previously identified allelochemicals include N-phenyl-1-naphthylamine, N-phenyl-2-naphthylamine and linoleic acid. This thesis investigated the presence or absence of key chemical compounds released by P. crassipes during allelopathy with microbes and phytoplankton to determine its potential to inhibit S. minima growth. Methanol extracts from P. crassipes roots, leaves, and field samples underwent LC-ESI-MS/MS analysis, creating a molecular network to match chemical profiles. Of the investigated compounds, N-phenyl-1-naphthylamine and N-phenyl-2-naphthylamine were absent in P. crassipes and field samples, while linoleic acid was consistently found. Its presence suggests its potential defensive role against S. minima. Future research should explore allelochemical production in the presence of S. minima and algae to confirm if S. minima elicits an allelochemical response by P. crassipes, or whether the methods used here were insufficient to detect allelochemical production. Understanding whether P. crassipes employs allelochemicals, especially in the presence of S. minima, could shed light on its competitive advantage beyond its invasive nature at the Dam. , Thesis (MSc) -- Faculty of Science, Botany, 2024
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- Date Issued: 2024-10-11
The expression and evaluation of CrpeNPV gp37 as a formulation additive for enhanced infectivity with CrleGV-SA and improved Thaumatotibia leucotreta control
- Authors: Muleya, Naho
- Date: 2024-10-11
- Subjects: Cryptophlebia leucotreta Biological control , False Codling Moth , Cryptophlebia leucotreta granulovirus , Cryptophlebia peltastica nucleopolyhedrovirus , Citrus Diseases and pests South Africa , Baculoviruses
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463919 , vital:76457
- Description: Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a significant pest native to Africa, causing damage to citrus and posing a threat to the export of fresh citrus in South Africa. Classified as a phytosanitary risk by several South African export markets, this pest necessitates effective control measures. Baculoviruses emerge as promising biological control agents against T. leucotreta due to their inherent safety and eco-friendly characteristics. Among these, Cryptophlebia leucotreta Granulovirus (CrleGV-SA) and Cryptophlebia peltastica Nucleopolyhedrovirus (CrpeNPV) stand out, both causing larval mortality upon infecting T. leucotreta. CrleGV-SA has been formulated into the products Cryptogran™, CryptoMax™ and Cryptex®, while CrpeNPV has been formulated into the product Multimax™. Both viruses are used in integrated pest management programmes to reduce fruit damage in agricultural fields, with CrleGV-SA having been employed against T. leucotreta for nearly 20 years in South Africa. However, these control options are limited by factors such as virulence and the slow speed of kill. This limitation can be addressed by exploiting potential synergistic relationships between baculoviruses infecting the same host. Previous studies have demonstrated that the truncated CpGV gp37 can enhance the infectivity of NPVs on other lepidopteran pests, such as Spodoptera exigua (Hübner). Although the mechanism behind this phenomenon remains unclear, it presents an opportunity to enhance the effectiveness of baculovirus-based management strategies. Notably, the genome of CrpeNPV encodes gp37, while CrleGV-SA lacks this gene. The potential interaction between CrleGV-SA and CrpeNPV gp37 remains unexplored. Therefore, investigating whether they exhibit synergistic or antagonistic effects is essential for optimising baculovirus-based management of T. leucotreta. This study aims to express CrpeNPV gp37 in a bacterial system and then evaluate its effect on larval mortality when combined with CrleGV-SA in laboratory bioassays. The initial step involved extracting genomic DNA (gDNA) from occlusion bodies (OBs) of CrpeNPV. A modified Quick DNA Miniprep plus kit was utilised, which entailed pre-treatment with Na2CO3 followed by neutralisation with Tris-HCI before gDNA extraction using the kit. Subsequently, the concentration of the gDNA was estimated using a Nanodrop spectrophotometer. Oligonucleotides targeting the CrpeNPV gp37 gene were designed for PCR amplification, with the gDNA serving as a template. The gp37 amplicon was identified through agarose gel electrophoresis and then gel purified in preparation for cloning. Secondly, the purified PCR product was cloned into the intermediate vector pJET1.2/blunt and then subcloned into the bacterial expression vector pCA528 through DNA ligation. The construction of recombinant plasmids (pJET-gp37 and pCA-gp37) was conducted and verified using Colony PCR, plasmid extraction, restriction enzyme analysis, and Sanger sequencing. Thirdly, the recombinant protein (6×His-SUMO-gp37) was expressed and purified using Nickel affinity chromatography and analysed through SDS-PAGE and Western blot techniques. The expression of 6×His-SUMO-gp37 was carried out at both 25 °C and 18 °C. A time course induction study was conducted, inducing transformed cells for 0-, 3-, 5-, and 24-hours post induction (hpi). SDS-PAGE and Western blotting of samples collected at various time points revealed that 6×His-SUMO-gp37, approximately 42 kDa in size, was visible from 3 hpi, with maximal expression at 24 hpi. Solubility analysis of 6×His-SUMO-gp37 was performed at both temperatures, showing solubility at 18 °C but predominantly present in the insoluble fraction. The soluble protein was purified under native conditions, while the insoluble protein was purified under denaturing conditions. Despite being unable to elute 6×His-SUMO-gp37 under native conditions, successful elution was achieved under denaturing conditions, confirmed via Western blot analysis. No further experiments were conducted on the eluted 6×His-SUMO-gp37 under denaturing conditions. Lastly, a preliminary surface dose bioassay was conducted to evaluate the efficacy of pelleted bacteria expressing 6×His-SUMO-gp37 in combination with CrleGV-SA against T. leucotreta neonates. Two lethal concentration doses of CrleGV-SA were prepared: a low concentration (2.96×104 OBs/mL) capable of killing 40 % of the T. leucotreta population, and a high concentration (2.96×105 OBs/mL) capable of killing 90 % of the population. The target protein, 6×His-SUMO-gp37, and the control, pCA528, were obtained by lysing the cells, centrifuging the samples, and collecting the insoluble fractions in pellet form. These fractions were then resuspended in PBS and used as treatments in combination with the prepared CrleGV-SA concentration doses. The concentration of the pellets was estimated using a Nanodrop spectrophotometer by measuring the absorbance at 280 nm. The bioassay results revealed that the combination of 100 μg/mL of pelleted bacteria expressing 6×His-SUMO-gp37 with CrleGV-SA had no effect on T. leucotreta larval mortality compared to CrleGV-SA alone. A one-way ANOVA was performed to assess differences among the virus treatment groups, concluding that no statistically significant differences were observed among the groups. The experiments in this study provided valuable insights for future research, particularly in exploring the use of a protein-virus combination as a novel method for pest control. , Thesis (MSc) -- Faculty of Science, Biochemistry, Microbiology & Bioinformatics, 2024
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- Date Issued: 2024-10-11
The impact of corruption on stock market performance : evidence from BRICS
- Authors: Kapase, Siphe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462724 , vital:76329
- Description: This thesis examines the impact of corruption perception on stock market performance across BRICS nations from 2010 to 2022 using a primarily quantitative approach. Grounded in theoretical frameworks such as Corruption as Grease, Corruption as Sand, and New Institutional Economics, the study employs the Panel Autoregressive Distributed Lag (ARDL) model. It explores how corruption perceptions influence stock market capitalization (MCAP) over various time horizons. It utilizes empirical data and advanced techniques like unit root testing and cointegration tests to provide insights into short-term fluctuations and long-term trends in financial markets. The findings reveal significant long-term negative effects of the corruption perception index (CPI) on MCAP. Higher levels of perceived corruption correlate with lower stock market capitalization over extended periods, underscoring the persistent impact of institutional weaknesses on market stability. Short-term analyses show varying adjustment speeds towards equilibrium among BRICS nations, reflecting different economic contexts and policy responses to corruption. The findings suggest that investors should focus on markets with lower corruption perceptions for better stock market performance and advise policymakers to enhance transparency to build more resilient financial markets. Future research should continue to explore the impact of corruption on BRICS nations. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
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- Date Issued: 2024-10-11
The impact of Fintech firms on bank performance: analysing the South African case (2009-2021)
- Authors: Runyowa, Simon Simbarashe
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/462812 , vital:76337
- Description: The growth of the Fintech Firm sector globally was inevitable, given the changes in consumer behaviour, expectations, and the ever-changing and evolving nature of technology. The sector saw a sharp increase during the 2008 Global Financial Crisis and was driven by digital payments, government policy, less stringent regulation, and technological innovation. Unsurprisingly, South Africa was home to a mature and developing Fintech sector primarily driven by money transfers and mobile payments putting Fintech firms in the same market segment as traditional banks but with a more extensive potential customer base through offering easily accessible and lower-cost services. The relationship between the growth of the Fintech firm sector and Bank performance was widely researched within the literature with varying results. The study aimed to add to the body of literature and determine the nature of this relationship in the South African context. The study primarily aimed to determine the relationship and impact of the growth of the Fintech firm payments segment on the performance of the South African Banking sector. Additionally, the study aimed to measure the sector's growth by creating a Fintech Growth Index. Using the Ordinary Least Squares, Fixed Effect and the Generalized Method of Moments estimation techniques, estimations between Bank performance variables and the Fintech growth Index were analysed between 2009 and 2021. Firstly, the study found the growth of the Fintech payments segment to be positive. Secondly, the study found that the growth of the payment segment had a negative relationship and impact on the financial performance of South African banks. The findings of this study have implications for the development and regulatory framework of the South African Fintech sector as well as its interaction with the South African banking sector. Furthermore, policymakers may find that the growth of the Fintech Firm sector has overall positive benefits for financial inclusion for South African consumers. The study recommended that future research be taken to address the gap in the literature regarding the growth of the South African Fintech sector. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
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- Date Issued: 2024-10-11
The impact of international investment agreements on FDI in developing countries and the implications for development policy
- Authors: Lomas, Djamella
- Date: 2024-10-11
- Subjects: Uncatalogued
- Language: English
- Type: Academic theses , Master's theses , text
- Identifier: http://hdl.handle.net/10962/463489 , vital:76413
- Description: This study investigates the impact of international investment agreements, specifically bilateral investment treaties (BITs), on inward Foreign direct investment (FDI) in recipient developing countries and the implications of such agreements for development policy. The study estimates a log-linear gravity model based on a unique dataset created to investigate whether the presence of BITs has a positive impact on inward FDI stock in 36 developing countries. The selection of countries attempts to capture a set of bilateral relationships that accounts for a significant proportion of inward FDI in developing countries. To test the hypothesis that signing BITs has a positive effect on inward FDI in developing countries it was necessary that all recipient countries be developing economies. However, investor countries are both developed and developing economies. Therefore, each bilateral FDI relationship is either between a developing recipient and developed investor country or between a developing recipient and developing investor country. For each recipient country, FDI stock data from investor countries for 2019 was obtained from the ITC’s Investment Map database (ITC, 2022). This yielded 1009 bilateral FDI relationships (observations for the dependent variable) after removing pairs for which certain explanatory variable data was not available. For the gravity model, GDP data was collected from the World Bank’s World Development Indicators Database (World Bank, 2023a), while the other traditional gravity variables were collected from the CEPII GeoDist Database (CEPII, 2011). Alongside the gravity variables, the study employs three additional control variables (two macroeconomic and one institutional) in certain specifications of the basic model, namely the exchange rate, inflation rate and an index of political stability. Data for the three additional variables was sourced from the IMF’s World Economic Outlook Database (IMF, 2022) for the macroeconomic variables and the World Bank’s Worldwide Governance Indicators Database (World Bank, 2023b) in the case of the political stability index. To examine the key question of the impact of BITs on bilateral FDI, a number of BITs dummy variables are created to investigate, firstly, whether having signed a BIT impacts on FDI in developing countries and, secondly, whether having a BIT in force significantly impacts on FDI in developing countries. Thereafter, in each case, dummy variables are created to investigate whether there is a significant difference between the impact on FDI of having a BIT signed or in force between a developed and developing country specifically, and having a BIT signed or in force between two developing countries. In order to examine the implications for development policy, the thesis analyses case studies of selected BITs between developed and developing economies, as well as those between developing economies. The texts of the BIT documents were obtained from the UNCTAD Investment Policy Hub Database (UNCTAD, 2023b). The results of the study reveal that, on average, signing and/or having a BIT in force has a significant positive impact on the inward FDI stock of the recipient developing country from the outward investor country. This positive impact is found to be even stronger in the case of BITs between developed and developing countries. However, there is no significant impact on inward FDI for BITs signed between two developing countries. The study finds that GDP of the recipient and investor country, existence of a common official language and the distance between countries all have a significant impact on FDI in the recipient developing country, and are signed as expected in the gravity literature. The existence of a common border is weakly significant in some specifications of the basic model and not significant in others. The additional control variables are all significant and signed as expected in the literature. The study contributes to the literature by distinguishing, not only between the impact of BITs signed versus BITs in force on inward FDI in developing countries, but also by distinguishing between the impact of BITs on FDI when the partners are developed and developing countries versus when both partners are developing countries. The study also finds that, in an effort to attract FDI, developing countries have signed BITs which carry obligations that extend significant protection measures to foreign investors. However, such protections are offered at the expense of sovereign interests. The study finds that this has served to significantly reduce the policy space available for developing countries to attract FDI that is aligned to their sustainable development needs. The limitations of the study are as follows. The gravity specification is cross-sectional, and a panel data approach could be recommended for future work. Furthermore, the traditional OLS gravity specification has a number of disadvantages and different types of estimator could be used in future work, software permitting. In addition, the impact on FDI of the termination of BITs could be investigated, as sufficient data is becoming available for such an approach. Finally, it is difficult to generalise from the case study analysis undertaken of specific BITs provisions because of the limited number of BITs examined in the thesis. , Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 2024
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- Date Issued: 2024-10-11