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Beyond mastery: jazz, gender and power in postapartheid South Africa
Get PDFThis dissertation studies the musical lives of seven South African women who have built highprofile national and international careers as jazz musicians. Empirically it records self-reported experiences and actions that they have identified as relevant to their success within a notoriously patriarchal field. Drawing on feminist research methods and Interpretative Phenomenological Analysis the dissertation strives to develop an empathic yet critical epistemological framework attuned to the complexities of their lived experiences as women and as jazz musicians. Theoretically it investigates the power relations at play in the myriad ways they negotiate or have been impelled to negotiate gender and patriarchy as musicians. Chapter one draws attention to the ubiquity of patriarchy in South African and international jazz culture, and highlights the research participants’ numerous successes to date as performers, educators, composers, and bandleaders. Chapter two positions this study in relation to cognate work in South African jazz studies, international feminist jazz studies and feminist phenomenology. Chapters three to five successively consider the participants’ early enculturation as musical and gendered subjects, their agentic responses to structures of patriarchy and/or race as emerging and established professionals, and the ways these experiences have found expression in some of their musical utterances as performers and composers. Fusing art and activism, the participants challenge and transcend masculinist discourses of mastery that still dominate South African jazz as a field of production and aesthetic practice.Thesis (PhD) -- Faculty of Humanities, Music and Musicology, 202
Porphyrinoid dyes for photodynamic anticancer and antimicrobial therapy treatments
Get PDFThe search for alternative therapies and non-toxic photosensitizer drugs that can efficiently generate cytotoxic reactive oxygen species for biomedical applications, such as in alternative photodynamic therapy (PDT) for cancer treatment and photodynamic antimicrobial chemotherapy (PACT) for drug-resistant bacteria treatment is on the rise. Nevertheless, the lack of photosensitizer dyes that absorb light strongly within the therapeutic window (620−850 nm) that can locally target the tumor and bacterial cells and generate singlet oxygen efficiently are some of the main challenges in PDT and PACT treatment. This study sought to address the challenges that impede PDT and PACT from realizing their full potential by synthesizing a series of meso-aryltetrapyrrolic photosensitizer dyes that absorb light within the therapeutic window. These include meso-tetraarylporphyrin (Por), A3-type meso-triarylcorrole (Cor), meso-tetraarylchlorin (Chl), and N-confused meso-tetraarylporphyrin (NCP) dyes with 4-thiomethylphenyl (1), thien-3-yl (2), thien-2-yl (3), 5-bromo-thien-2-yl (4), 4-methoxyphenyl (5), 3-methoxyphenyl (6), 4-hydroxyphenyl (7) and 4-hydroxy-3-methoxyphenyl (8) meso-aryl rings. Por, Cor, Chl and NCP dyes and and their Ga(III), P(V), In(III) and/or Sn(IV) complexes with 1-8, 1-4, 5-8 and 5 meso-aryl rings were studied, along with two A2B-type Ga(III) meso-triarylcorroles with pentafluorophenyl rings at the A2 positions and 3,6-di-t-butyl-9H-carbazole (9) or N-butyl-4-carbazole (10) rings at the B position that were prepared in the laboratory of Prof. Xu Liang of Jiangsu University in the People’s Republic of China. The carbazole nitrogen of 10-GaCor was quaternized at Rhodes University with ethyl iodide to form a cationic species (10-GaCor-Q) for PDT and PACT activity studies. The structures of the synthesized dyes were confirmed using UV-visible absorption and 1H NMR spectroscopy, and MALDI-TOF-mass spectrometry. 1-4-InPor In(III) porphyrins, 1-4-PVCor, 1-4-GaCor A3 PV and GaIII corrole dyes were also conjugated to gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) via sulfur-gold and sulfur-silver affinities. The successful conjugation of the dyes onto the nanoparticles to form dye-AuNP or dye-AgNP nanoassemblies was confirmed using transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray powered diffraction (XRD), and (X-ray photon spectroscopy) XPS. The photophysicochemical, photostability, and lipophilicity properties of the dyes and their PDT and PACT activities were investigated, and the structure-property relationships were analyzed. This was accomplished by analyzing the changes in the properties of the dyes due to the meso-aryl substituents, central ions, molecular symmetry, and heavy atom effects. Time-dependent-density functional theory (TD-DFT) calculations were also used to further probe the electronic and optical spectroscopic properties of the dyes. The analysis of the photophysicochemical, photostability, and lipophilicity data for the synthesized dyes demonstrated that there are inherent structure-property relationships for the dyes studied. The TD-DFT calculations also assisted in rationalizing the observed optical spectroscopic data for the dyes. The introduction of different meso-aryl substituents resulted in minor absorption spectral changes on the parent structures of the dyes due to their inductive and mesomeric effects, while the insertion of Ga(III), In(III), and Sn(IV) electropositive metal centers resulted in marked red shifts of the B bands due to favorable interactions with the porphyrin or porphyrinoid ligand core. The lower symmetries of the corrole, chlorin, and N-confused porphyrin dyes resulted in enhanced absorption properties within the therapeutic window relative to porphyrins. The heavy atom effect from the Ga(III), In(III), and Sn(IV) central ions, the meso-aryl groups, and the external heavy atom effect from the AuNPs and AgNPs significantly reduced the fluorescence quantum yield values of the dyes resulting in high singlet oxygen quantum yields. The dye complexes also exhibited properly balanced lipophilic properties and high photostabilities. The P(V) ion of the A3 PV corrole dyes reduced the aggregation effects, enhanced cellular uptake, and lowered the lipophilicity values relative to the A3 GaIII corrole dyes. The porphyrin and porphyrinoid complexes studied exhibited relatively low in vitro dark cytotoxicity toward MCF-7 cancer cells, which is enhanced for AuNP nanoconjugates of 1-InPor, 1-3-PVCor, and 1-3-GaCor. The dyes also have low in vitro dark cytotoxicity toward planktonic and biofilm cells of S. aureus and E. coli. The complexes also exhibited favorable PDT and PACT activities toward MCF-7 cancer cells, and planktonic and biofilm S. aureus and E. coli bacteria due to their high singlet oxygen quantum yields. AuNP and AgNP nanoconjugates of 1-4-InPor, 1-4-PVCor, and 1-4-GaCor exhibited enhanced PDT and PACT activities due to the favorable synergistic effects of nanoparticles. The PDT and PACT activities of A3 PV corrole dyes and the nanoconjugates of 1-4-PVCor are slightly higher than those of A3-type GaIII corroles and their nanoconjugates due to decreased aggregation effects and enhanced PS drug uptake. The cationic 10-GaCor-Q species also exhibit favorable PDT and PACT activities in contrast to the neutral 9-10-GaCor dyes due to enhanced PS drug penetration into the tumor or bacteria cells. The complexes also exhibited high Log10 reduction values for planktonic S. aureus suggesting that the dyes are highly efficient PS dyes. The activities of the complexes toward planktonic E. coli bacteria are moderate except for 10-GaCor-Q, 2-4-PVCor-AgNPs, and 5-8-SnChl chlorins exhibiting relatively favorable activity with > 3 Log10 CFU.mL−1 values. The dyes also exhibit moderate activities toward the S. aureus and E. coli biofilm cells, which are lower than for the planktonic cells, as shown by their lower Log10 reduction values. The data demonstrate that the low symmetry corrole, chlorin, and N-confused porphyrin complexes that absorb light strongly within the therapeutic window have significantly enhanced PDT and PACT activities relative to their porphyrin analogs.Thesis (PhD) -- Faculty of Science, Chemistry, 202
Prediction of mass spectra using an ab initio approach
Get PDFAccess restricted. Expected release date in 2025.Thesis (PhD) -- Faculty of Science, Chemistry, 202
The impact of COVID-19 on inequality in South Africa
Get PDFThe COVID-19 pandemic has raised concerns regarding its possible adverse income distributive consequences, and its different impact according to socioeconomic subgroups (Furceri et al. 2020). This research measures the impact of COVID-19 on inequality in South Africa. To do this the study uses the National Income Dynamic Study (NIDS) wave 5 (2018) and the National Income Dynamic Study Coronavirus Rapid Mobile (NIDS-CRAM) survey waves 1 – 5 (2020 - 2021) datasets to study income inequality in South Africa prior to and during the COVID-19 pandemic until mid-2021. The factor method developed by Lerman and Yitzhaki’s (1985) is used to identify the overall contribution of the different factor sources to income inequality. Labour income is identified as the largest contributing factor and so labour income inequality is decomposed by income determinants using the regression-based decomposition method proposed by Fields (2003). The analysis reveals that labour income worsened during the periods of strictest COVID lockdown, before returning to pre-pandemic levels of inequality as lockdown was eased. Education is the most important determinant of labour income inequality across all time periods, particularly for White, urban and female participants. Although education remains a driving factor of labour income inequality during the national disaster, its contribution lessens as the economy starts recovering by March 2021. Consequently, the contributions of gender, race, age and region increase during the same period. Identifying whom the inequal impact of pandemic has affected worse offers insight that emphasizes the importance social grant systems to aid bridge the inequality gap associated with COVID-19.Thesis (MEcon) -- Faculty of Commerce, Economics and Economics History, 202
Ubulunga obusisiyaca obunentsimbi
No full textThe ubulunga obusisiyaca obunentsimbi, a necklace steeped in cultural significance, is crafted from pristine white beads interwoven with the supple tail hair of a heifer cow. This unique combination of materials symbolises purity and connects the wearer to the sacred realm of ancestral wisdom. Traditionally donned by diviners, and oracles who bridge the earthly and spiritual realms, this necklace serves as a channel for divine insight and guidance. Each bead and strand of hair carries with it a lineage of ancestral knowledge, passed down through generations. With its ethereal beauty and spiritual resonance, the ubulunga obusisiyaca obunentsimbi embodies the profound connection between the tangible world and the mystical forces that shape it, making it an indispensable artefact in traditional African spirituality.Purchased from Mrs Joan BrosterForms part of: Walter Sisulu University Beadwork Collectio
M3: Mining Mini-Halos with MeerKAT
Get PDFThis work aims to showcase the MeerKAT telescope’s capabilities and related calibration and imaging software in studying the emission of radio mini-halos. These diffuse radio synchrotron sources surround a Brightest Cluster Galaxy (BCG) in relatively relaxed clusters out to a few 100 kpc in size. They are difficult to image because of their relatively low surface brightness and small angular size. Hence, they could not be studied in great detail by previous generations of radio telescopes and much about their nature, particularly the exact production mechanism, is not yet fully understood. Thus, for the first time, MeerKAT observed a sample of five galaxy clusters to investigate the central radio mini-halo in each. Studying these sources requires the deepest images generated from the data and the effective subtraction of any projected sources obscuring or contaminating the underlying diffuse emission. Therefore, I describe the data reduction used to create third-generation calibrated, primary beam corrected, point source subtracted Stokes I L-band continuum images of these clusters. For first- and second-generation calibration, I use the CARACal pipeline, which implements software optimised explicitly for MeerKAT data. For third-generation calibration, I use the faceted approach of killMS and DDFacet, and then I perform visibility-plane point source subtraction to disentangle the compact and diffuse emissions. I then measured the size, flux density, in-band spectral properties, and radio power of the central mini-halos. I present the first new mini-halo detection by MeerKAT (MACS J2140.2-2339, Trehaeven et al. accepted), the first spectral index maps of these mini-halos, which show very interesting distributions, and a ∼100 kpc II southern extension to the ACO 3444 mini-halo previously unseen in archival VLA data. Thereafter, I present a multi-wavelength case study for two complementary mini-halos from our sample and show via a radio-to-X-ray spatial correlation test that they might be caused by different particle (re)-acceleration mechanisms. Through these initial science results, I have shown that future observations of radio mini-halos with MeerKAT are an exciting prospect that can lead to a better understanding of the fundamental physics behind these sources.Thesis (MSc) -- Faculty of Science, Physics and Electronics, 202
The application of statistical classification to predict sovereign default
Get PDFWhen considering sovereign loans, it is imperative for a financial institution to have a good understanding of the sovereign they are transacting with. Defaults can occur if proper evaluation steps are not considered. To aid in the prediction of potential sovereign defaults, financial institutions, together with grading companies, quantify the risk associated with issuing a loan to a sovereign by developing sovereign default early warning systems (EWS). Various classification models are considered in this study to develop sovereign default EWS. These models are the binary logit, probit, Bayesian additive regression trees, and artificial neural networks. This study investigates the predictive performance of the various classification techniques. Sovereign information is not readily available, so missing data techniques are considered in order to counter the data availability issue. Sovereign defaults are rare, which results in an imbalance in the distribution of the binary dependent variable. To assess data sets with such characteristics, metrics for imbalanced data are considered for model performance comparison. From the findings, the Bayesian additive regression technique generated better results than the other techniques when considering a basic data analysis. Moreover when cross-validation was considered, the neural network technique performed best. In addition, regional models had better results than the global model when considering model predictive capability. The significance of this study is to develop sovereign default prediction models using various classification techniques focused on enhancing previous literature and analysis through the application of Bayesian additive regression trees.Thesis (MSc) -- Faculty of Science, Statistics, 202
Efficacy of recapitalisation and development programme: A comparative study of the citrus farms in Amathole district
Get PDFThe majority of the land reform beneficiaries have remained poor, with some being worse off than before. Despite the various government initiatives to address issues of food insecurity and poverty alleviation, there has been slow progress in terms of producing enough food to ensure local and national food security. In South Africa, the Recapitalisation and Development Programme (RECAP) was initiated to alleviate the challenges faced by land redistribution and restitution recipient farmers such as inadequate post-settlement support to increase farms production output in order for them to become successful commercial farms. Several farmers have benefitted from this programme and the have been able to increase production output while others are still struggling, or worse showing zero output. These mixed outcomes call into question the efficacy of RECAP and the need to understand why some farmers are successful while others are not. This study adopted a qualitative comparative case study approach of six RECAP beneficiary citrus farms located in the Amathole District of the Eastern Cape as well as their respective strategic partner and mentors. The findings of the study were analysed with the employ of reflexive thematic analysis. The study found that RECAP recipient citrus producers in Amathole have experienced varying degrees of success with access to finance being the key obstacle to success. Significantly, the study found that the challenges around finance do not relate primarily to the purchase of inputs to production, as was the previous understanding, but rather relate to the securing of title deeds and having a history of receiving finance which combined allow farmers to access additional finance when needed. The findings of this study have practical implications for policymakers as land reform and food security remain key Development challenges in South Africa that have been exacerbated by climate change.Thesis (Ma) -- Faculty of Faculty of Business and Economic Sciences, 202
Wage differentials by sector and gender in Botswana
Get PDFThe study examines wage differentials in the public and private sectors and gender wage gaps within these sectors in Botswana. Raw data from three nationally representative surveys collected is used. These surveys include the 2005/06 Labour force, the 2015/16 Multi-Topic Household and the 2019 Quarterly Multi-Topic. To address the set objectives, the study utilises the quantile regression model and decomposition methods proposed by Firpo, Fortin and Lemieux (2009) and further used the reweighted RIF-OLS OaxacaBlinder decomposition method proposed by Rios-Avila (2020). Results from three surveys demonstrate evidence of wage inequalities in Botswana. Findings revealed that the wage differential in the public and private sectors has weakened over the years, though it is still a significant concern. The public-private sector wage gap decreased from 72% in 2005/06 to 56% in 2019. However, a different trend is observed in the gender wage differentials, where the gap gradually increased over time. Gender wage gaps in the public sector were 4% in 2005/06; in 2015/16, the gap increased to 27% and 49% in 2019. On the other hand, in the private sector, the average wages were 7.34 and 6.98 for males and females in 2005/06, respectively, implying a wage gap of 35%. This trend holds for the other two samples. The gender wage gap in 2015/16 fell to 23% and increased to 28% in 2019. Results from the quantile regression estimates show that returns to education differ in both the sectoral and gender sections. Further, for males and females, returns for education tend to rise as the education level increases. Returns for education for the private sector are higher than for the public sector. For gender wage differences, education returns for females are higher than for males at all levels, supporting findings that females are more educated on average than males. For decomposition results, findings show that observed characteristics, such as education levels, negatively affect wages at the lower levels and positively at other parts of the distribution in the sectoral wage section. For the gender wage gap section, results show that workers’ characteristics had mixed contributions to the wage gap; it narrows the gap at the lower levels and widens it at higher levels of the wage distribution. Further, results suggest the presence of labour market discrimination and evidence of the “sticky-floor” viii effect in both sectors. Additionally, findings from the reweighting RIF-Oaxaca estimates show that the public-private sector wage gap takes an inverted U-shaped distribution in different levels of the wage distribution. Similarly, composition effects positively affect the gap at lower levels, whereas wage structure effects affect the wage gap at the highest distribution level. Overall, the study’s findings have some significant policy recommendations. The study has indicated that the country has no policy to reduce or eliminate wage differentials in the labour market. Hence, Botswana policymakers need to formulate policies to eliminate wage inequalities. Furthermore, it is recommended that the government should continue investing in human capital development. Education is vital in bridging the wage gap within the labour market. Additionally, there is a need to promote tolerance within society and promote ways of appreciating women’s work. It is also recommended that males be encouraged to work in jobs where women are overrepresented. The study's findings contribute to the ongoing wage inequality debate, and it is hoped that the study will benefit policymakers in Botswana.Thesis (PhD) -- Faculty of Faculty of Business and Economic Sciences, 202
Photodynamic therapy using morpholine substituted porphyrins in the presence of cancer specific molecules linked to graphene quantum dots
Get PDFThis thesis reports on the synthesis, characterization, photophysiochemical properties of morpholine substituted symmetrical and asymmetrical porphyrins. The synthesized porphyrins are conjugated to cancer selective biomolecules (folic acid and biotin) which are linked to nitrogen doped graphene quantum dots, as potential photosensitizers for photodynamic therapy (PDT). The symmetrical morpholine porphyrin complexes 2 (Sn(IV) 5,10,15,20 tetra-4-morpholinyl porphyrin) and 3 (Zn 5,10,15,20 tetra-4-morpholinyl porphyrin) had the same substituent but different central metals, and they were both conjugated to biotin decorated nitrogen doped graphene quantum dots (B-NGQDs), however complex 2 (Sn(IV) 5,10,15,20 tetra-4-morpholinyl porphyrin) was conjugated to B-NGQDs through an ester bond and complex 3 (Zinc 5,10,15,20 tetra-4-morpholinyl porphyrin) through - stacking. The effect of asymmetry was studied by comparing complex 3 (Zn 5,10,15,20 tetra-4-morpholinyl porphyrin) and complex 5 (Zn 5- bromophenyl-10-15-20-(tris-4- morpholinyl) porphyrin). Complex 5 (Zn 5- bromophenyl-10-15-20-(tris-4- morpholinyl) porphyrin) was an asymmetric porphyrin with morpholine and bromine as substituents. It was observed that asymmetry enhances singlet oxygen quantum yield and PDT activity. It was also observed that folic acid is a better targeting biomolecule when compared to biotin, and this was studied by comparing complex 3 conjugated to B-NGQDs and complex 3 conjugated to folic acid decorated nitrogen doped graphene quantum dots (FA-NGQDs). 3-FA-NGQDs had a better cellular uptake and PDT activity.Thesis (MSc) -- Faculty of Science, Chemistry, 202