A Feasibility Study on the Efficacy of Functional Near-Infrared Spectrometry (fNIRS) to Measure Prefrontal Activation in Paediatric HIV

Human immunodeficiency virus (HIV) infection is associated with disturbed neurotransmission and aberrant cortical networks. Although advances in the imaging of brain microarchitecture following neuroHIV has added to our knowledge of structural and functional changes associated with HIV, no data exists on paediatric HIV using optical neuroimaging techniques. This study investigated the feasibility of optical neuroimaging in paediatric HIV using functional near-infrared spectrometry (fNIRS). We measured prefrontal brain activation while participants executed a sustained attention task. We specifically tested whether patients living with HIV and study controls could perform the study protocol and whether we could measure the typical fNIRS haemodynamic response associated with neuronal activity. Eighteen participants (10 HIV participants, mean age: 13.9, SD = 1.66 years; 8 controls, mean age: 14.8, SD = 1.28 years), matched for sex, grade, and socio-economic status, were included in the study. All participants completed the Stroop colour word test (SCWT). Oxygenated haemoglobin concentration and the deoxygenated haemoglobin signal were recorded from the dorsolateral prefrontal cortex and the frontopolar area (FA) using fNIRS. The control group performed significantly better in terms of reaction time on the congruent and incongruent condition (congruent: t (16) = −3.36, : incongruent: ). A pooled group analysis of the sample indicated significant activation in the DLPF and FA to the congruent condition of the SCWT (). Although cortical activation was noted in the DLPF and the FA in each of the groups when analysed independently, this neural activation did not reach statistical significance. The results show promise that fNIRS techniques are feasible for assessing prefrontal cortical activity in paediatric HIV. Future studies should seek to reduce the signal-to-noise ratio and consider inter-individual variability when measuring prefrontal activation in paediatric samples

An investigation into the impact of geographical location on the phytochemical composition, pharmacological and toxicological activities of Tulbaghia violacea collected from the Eastern Cape and Gauteng Province

Introduction: The number of communicable and non-communicable diseases continues to rise and has become more prevalent. While drugs exist to manage and/ or treat majority of the communicable and non-communicable diseases, the rise in disease prevalence puts pressure on researchers to find new drug molecules to treat and manage these ailments. Traditional medicine refers to the knowledge, skills and practices which are based on the beliefs and experiences indigenous to cultures and is used to maintain health. Most of the research into traditional medicine focuses on the medicinal plants used. Medicinal plants are any plants in which one or more of its organs contain substances which are used for therapeutic purposes or for the synthesis of drugs. Tulbaghia violacea is a monocotyledonous genus of herbaceous perennial bulbs which is native to Africa and can be readily found throughout South Africa. It is popular for its antimicrobial, antifungal, anticoagulant, antioxidant and anticancer properties. It has been that ecological factors influence the composition and quantity of phytochemicals present in a plant. Aim of the study: The aim of the study was to investigate the impact of geographical location on the phytochemical composition, pharmacological and toxicological activities of T. violacea collected from the Eastern Cape and Gauteng Province. Methods: The leaves of T. violacea were collected from the Eastern Cape and Gauteng Province. The leaves were dried and extracted using serial maceration with solvents hexane, acetone and methanol. The resulting extracts were subjected to qualitative preliminary phytochemical analysis and a quantitative total phenol content test was carried out using gallic acid as the standard. Thin layer chromatography (TLC) was performed to identify classes of compounds present in T. violacea. xix Antioxidant activity of T. violacea was determined qualitatively using a dot-plot and quantitatively using a DPPH radical scavenging activity assay. Ascorbic acid was used as the standard. Anti-diabetic properties of T. violacea were assessed using an α- amylase inhibition assay and an α- glucosidase inhibition assay. Acarbose was used as the standard for these assays. The anti-Alzheimer properties of T. violacea leaf extracts was determined using and acetylcholinesterase (AChE) inhibition assay. Donepezil was used as the standard for this assay. The DPPH radical scavenging activity, the α- amylase inhibition assay, the α- glucosidase inhibition assay and the AChE inhibition assay was combined with linear regression to determine the IC50 values of the T. violacea extracts and the standards. Statistical analysis was conducted to determine any differences between the plant samples and the standards as well as any differences between the EC and GP sample. Results: The results of the qualitative phytochemical analysis revealed the presence of saponins, flavonoids, tannins, alkaloids, steroids, cardiac glycosides and phenolic compounds present in T. violacea collected from EC and GP. However, their presence in the samples were different based on where the plant was cultivated. The results of the total phenolic content test, revealed that the hexane, acetone and methanol extracts of T. violacea contained phenolic compounds with the highest quantity of phenolic compounds being present in the methanol extracts. Significant statistical difference in total phenolic content between the EC and GP samples were seen for the hexane and methanol extracts. The results of the TLC revealed the presence of multiple bands which confirmed the presence of multiple phytochemicals in T. violacea. All of the extracts of T. violacea from EC and GP, showed antioxidant activity using both the dot-plot and the DPPH radical scavenging activity assay. The highest DPPH radical scavenging activity was seen by the hexane extract of the EC sample of T. violacea. The results showed significant statistical difference between the DPPH radical scavenging activity of the EC and GP samples.Thesis (Msc (Pharmacy)) -- Faculty of Pharmacy, Pharmacy, 202

An exploratory study of leadership and organisational change through the lens of organisational behaviour: a secondary school in Makhanda

Access restricted. Expected release in 2025.Thesis (MSocSci) -- Faculty of Humanities, Sociology, 202

Effects of household debt on economic growth in South Africa

South Africa’s household debt relative to GDP has risen rapidly over the past decade. There is concern that high levels of household debt may decrease spending in the future and hence in the long run slow down economic growth. Thus, this study investigates the impact of household debt on growth in South Africa from 1987Q3 to 2022Q1. The research draws upon first-generation theories which include the absolute income hypothesis, life cycle hypothesis, and permanent income hypothesis, and second-generation theories which include the neo-Kaleckian model, the Super multiplier model, and the Steindl model. The impact of this relationship is assessed using a Vector Autoregressive (VAR) model, with a Toda-Yamamoto modification for some regressions. It is discovered that household debt has a positive short-term influence on economic growth, however, the influence is weak, and it decreases in the long run. Types of household debt such as credit card debt have shown to have a positive and strong influence on economic growth in South Africa from the short run to the long run, however, mortgage debt has shown weak positive influence on economic growth from the short 105 run to the long run. The study found that the growth maximizing ratios for household debt to 106 GDP ratio is 70 percent. The growth maximising credit card debt level is ZAR 72 403, in nominal terms and for mortgage debt is ZAR 5 980 000. The findings are expected to assist policymakers such as central banks and government authorities in formulating relevant policies to ensure economic sustainability through macro-prudential policy and strategies for household debt management.Thesis (MEcon) -- Faculty of Commerce, Economics and Economic History, 202

Short Composition Portfolio

Short Composition Portfolio (60% performance/40%short-compositionportfolio).Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 202

Tradition and change in the Imfene dance of the amaMpondo in the Ntabankulu district of the Eastern Cape province

Access restricted. Expected release 2025.Thesis (MMus) -- Faculty of Humanities, Music and Musicology, 202

Social justice implications of the language of the court judgment genre and its development in pre- and post-independence Zimbabwe

Access restricted. Expected release in 2026.Thesis (PhD) -- Humanities, Linguistics and Applied Language Studies, 202

Encroaching species are stronger anisohydric “water spenders” under elevated CO2 conditions: implications for savanna seedling establishment rates

Plant water transport systems play a fundamental role in the productivity and survival of terrestrial plants due to the vascular architecture placing a physical limit on metabolic function. Savannas have high variability in rainfall, leading multiple studies to suggest that plant water-use strategies are key mechanisms affecting seedling establishment rates. Many savannas are seeing a directional shift towards an increase in the abundance of certain woody species through a process known as bush encroachment, which has been largely attributed to the fertilising effect of rising atmospheric [CO2] on C3 trees. These species are classified as encroachers. While there have been multiple studies investigating changes in the physiology of savanna species under elevated CO2 (eCO2), few have examined how climate and eCO2 affects the fundamental water-use strategies in the seedling stage, a crucial demographic bottleneck. Here, this research provides valuable insights into the mechanisms behind bush encroachment in the context of eCO2 using results from a pot experiment at the Rhodes University Elevated CO2 facility and a field experiment. All species showed water use strategies characteristic of anisohydric “water-spenders”, however, the vulnerability to embolism and rates of water-use were different between encroachers and non-encroachers. Encroachers are better at taking advantage of water pulses, particularly under eCO2 and grass competition. This comes at the cost of higher xylem vulnerability during drought, leading to reductions in conductance when exposed to heavy water stress. The response of the photosynthetic parameters mirrored this, with encroaching species had higher rates of photosynthesis and photosystem II quantum yield than non-encroachers under the well-watered treatments. Field experiments revealed that small trees are particularly vulnerable to drought stress, when compared to medium and large trees. The outcomes of this complex response will largely depend on the extent of changes to biotic and abiotic factors across spatial and temporal zones caused by climate change. This research highlights potential hydraulic mechanisms contributing to the increase in bush encroachment, as well as providing important insights into the determinant factors that make a savanna species capable of encroachment.Thesis (MSc) -- Faculty of Science, Botany, 202

The relationship between REITS and stock market prices during periods of volatility: a Bivariate GARCH analysis

The relationship between real estate and the stock market is essential because they are the two most highly invested assets. In addition, examining the volatility of any asset is important for risk management and investor portfolio returns. The general motivation for analysing the relationship is that it can provide insight to policymakers and investors about the behaviour of stocks and real estate assets. The purpose of this research is to examine the relationship between Real Estate Investment Trusts (REITS) and stock prices in South Africa using daily data from 2 January 2013 to 31 May 2023. The wealth and credit effects are the two mechanisms used to interpret the relationship. The wealth effect is a mechanism that states that the causal relationship between the two markets runs from increasing stock prices which tends to increase real estate. The credit effect claims that real estate prices influence stock prices. Most of the existing literature has examined the relationship between the two markets but less attention has been given to the volatility spillover effects. Therefore, the analysis presented in this thesis extends the existing research by examining the relationship and the spillover effects between the REITs and stock markets. The study employs quantitative research methodology using the following econometric methods i)Vector Autoregression model, ii) Granger Causality Tests and Bivariate GARCH models. The study found that there is no long-run relationship between REITS and stock prices. In addition, the Granger Causality results showed a unidirectional relationship between REITs and stock prices. The results indicate the presence of a wealth effect in South Africa, meaning that changes in stock prices influence the real estate market. Moreover, the GARCH analysis found volatility spillover effects from the stock to the REITs markets. These results are helpful for policymakers and investors interested in the portfolio and risk management of the two markets.Thesis (MCom) -- Faculty of Commerce, Economics and Economic History, 202

Aspects of the water use of Cannabis sativa L. under dryland cultivation in the Eastern Cape

Cannabis spp is one of the oldest cultivated plants, with its origin in Asia. It has two species, namely C. indica and C. sativa. This research focuses on C. sativa, which is widely cultivated locally and globally. C. sativa has a wide range of uses, including industrial, medicinal, religious, and recreational. This study will be focusing on the water use of medicinal and recreational C. sativa grown under dryland conditions. In recent years, there has been a growing interest in increasing its cultivation, but there are reports of it having high water usage. The global interest has led many governments to review the laws governing this plant as it is a controlled substance in many countries. Due to its legal status, there is a dearth of knowledge about its growth and water use. It is against this backdrop that the Water Research Commission (WRC) commissioned this study into the water use of this plant. This will provide evidence-based support for the issuing of water use licenses by the Department of Water and Sanitation. The Eastern Cape and KwaZulu Natal have many small-scale legacy farmers who have been growing C. sativa illegally for decades. The findings of this research will seek to fill some of these knowledge gaps and assist legacy farmers in the cultivation of this plant. This research had four approaches, which include 1) planting the crop in a dryland location that will mimic the conditions experienced by legacy growers, 2) the collection of plant biophysical variables in the study site in order to gain a better understanding of the plant’s health, growth, progress, and to use these variables to parameterize a mechanistic eco-physiological model, 3) the installing of a large aperture scintillometer (LAS) together with a micro-meteorological station to measure the evapotranspiration (ET) and meteorological parameters over a crop cycle, 4) to use MEDRUSH evapotranspiration model to predict the ET and compare these results against that of the LAS. The results show that water provision had a significant impact on plant biophysical variables and water use. The plants received 154 mm (2 mm day-1) of rain during the crop cycle. The large aperture scintillometer recorded a total ET of 126.8 mm (1.76 mm day-1) during the same period. The MEDRUSH model (2.5 mm day-1) overestimated the LAS ET (1.79 mm day-1), and the results from the daily ET revealed that C. sativa had higher daily ET when compared to the local grass Eragrostis plana. These results confirm that at this location in the Eastern Cape, C. sativa requires regular irrigation during the growing season to grow and secure a crop.Thesis (MSc) -- Faculty of Science, Institute for Water Research, 202