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Disability and Migration: A photovoice study on the lived experiences of Zimbabwean refugee mothers of disabled children living in the Western Cape, South Africa

(Stellenbosch : Stellenbosch University, 2024-12) Tarusarira, Willson; Geiger, Martha; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Health and Rehabilitation Science.

This qualitative study explored the lived experiences of Zimbabwean refugee mothers of disabled children living in the Western Cape Province of South Africa. The main research question was: What are the lived experiences of Zimbabwean refugee mothers of disabled children in the Western Cape Province of South Africa? The sub questions focused on the three migratory phases: i.e. What are the lived experiences of Zimbabwean refugee mothers of disabled children (1) before they leave Zimbabwe (2) during their migratory journey to South Africa and (3) after arriving in the Western Cape Province of South Africa. In collecting data, I used photovoice and narrative inquiry methods. Volunteer sampling through a Non-Profit Organization (PASSOP), was used to recruit the participants, thus, 12 Zimbabwean refugee mothers of disabled children. Interviews were conducted in English with Shona and Ndebele explanations, to gain insights into their lived experiences. Thematic analysis was applied to the participants' verbal explanations of their photographs and their narratives covering the pre-migration, trans-migration, and post-migration phases. the three migration phases i.e. two themes were identified in the pre migration phase, thus, (a) Traditional beliefs about the causes of child disability and (b) consequences for mothers after giving birth to a disabled child. On trans-migration, one main theme was identified(c) Challenges in cross border travelling with a disabled child. During post-migration, two themes were identified: (d) Discrimination of mothers when accessing basic services at government departments. (e) Discrimination by host communities. Although most Zimbabwean refugees living in South Africa have been forced to migrate due to political and economic challenges as previously identified, this study established that participants migrated to South Africa because of the hostile traditional beliefs about child disability. Because of these hostile traditional beliefs, these mothers were forced to flee for the safety of their disabled children and themselves. Furthermore, travelling with a disabled child was challenging. During their journey, mothers faced stigma for travelling with a disabled child, in addition to the challenges faced by others (e.g., not having travelling documents and having to walk long distances, cross the crocodile infested Limpopo River, pay bribes to the police, and use illegal entry points risking being sexually abused by fellow migrants, and gang members along the way. Distressed by their pre-migration, and trans-migration experiences, participants continued to face challenges in South Africa because of their disabled children. This study demonstrated that this traumatising background experience of these mothers undermined their ability to cope with a lot of challenges in South Africa, for example xenophobia. This study revealed that xenophobia can be interpersonal or structural violence, such as being socially and economically marginalised. When seeking basic services for their disabled children, they are confronted with xenophobic attitudes from service providers such as the staff at government departments including the Home Affairs Department, Hospitals and Clinics, Police and Social Services. Participants reported that some service providers withheld basic services for their disabled children. Moreover, mothers reported that they encounter xenophobic attacks in the communities where they reside. Mothers are suspected by the communities of stealing their jobs, and of straining the South African health system. Although none of the participants received the SASSA grant, they reported being attacked by community members who believed that their disabled children are benefiting from the SASSA grant. In a nutshell, the challenges of these mothers started during their time in Zimbabwe and continued during their journey to South Africa, and when they resettled in South Africa. Recommendations are therefore identified for stakeholders on the Zimbabwean side regarding knowledge, attitudes and practices concerning persons affected by disability and everyone concerned with the integration of refugee mothers of disabled children in South Africa, including the government, the media, future researchers, refugee mothers of disabled children themselves, and the communities where they reside.

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Alkaline amino acids in gold leaching: chemistry and application to Witwatersrand tailings

(Stellenbosch : Stellenbosch University, 2024-12) Tapfuma, Anthony; Tadie, Margreth; Akdogan, Guven; Stellenbosch University. Faculty of Engineering. Dept. of Chemical Engineering.

In gold processing, high-grade gold reserves with readily accessible gold deposits are being exhausted thereby increasing interest in the mining and processing of low-grade gold sources. The readily available low-grade gold sources are gold tailings, which are abandoned and abundant all over the globe. The processing of abandoned gold tailings is a crucial component of gold processing which can benefit economic and environmental perspectives. Currently, the cyanidation process is used in extracting gold from tailings due to its high selectivity and the ability to form very stable gold complexes, which leads to high gold recoveries. Despite the popularity of the cyanidation process, it poses environmental hazards, leading to the search for alternative lixiviants for the leaching of gold tailings. Amino acids have been identified as environmentally benign alternatives for leaching gold. Therefore, this study investigated the use of glycine, alanine, cysteine, and histidine in the leaching of gold, focusing on understanding the novel complexation/bonding chemistry, pure gold dissolution kinetics and the application in the leaching of Witwatersrand tailings. In fulfilling the investigations, a number of objectives were achieved and these included : (i) to assess the current status of amino acid utilisation in gold leaching, (ii) investigate gold-amino acid complexation through Fourier-transform infrared spectroscopy (FTIR), (iii) utilise Density Functional Theory (DFT) calculations to investigate gold-amino acid complexes, (iv) investigate pure gold dissolution conditions, (v) analyse gold electrochemical oxidation through linear sweep voltammetry, (vi) evaluate leaching of gold from Witwatersrand tailings, and (vii) propose a leaching mechanism for the study. The literature review covered the current status of amino acid use in gold leaching, looking at potential studies conducted and possible applications in secondary sources. The FTIR analysis showed that all four amino acids interacted with gold using the anchoring bonds on their carboxylic and amine ends. In addition, cysteine showed an extra bond using the sulphur in its R group. Furthermore, the FTIR work demonstrated that all four amino acids exhibited high bond shifts on the amine bond (NH2, NH3+) and carboxylic (COO-) bond at deprotonation pH compared to isoelectric pH. DFT calculations were done to predict the different complexes that different amino acids can form with gold. The geometric optimisation done showed that bonding of amino acids and gold was possible through donor atoms such as N, O and S. The bonding/complexation energy analysis also showed that the deprotonated amino acids can easily form complexes with gold compared to zwitterion, and this supported the FTIR finding. The thermodynamic behaviour investigations showed that the deprotonated amino acid complexes with gold were more stable than their counterparts. In addition to the FTIR interactions and DFT work, dissolution showed that gold dissolution was higher for the deprotonated system than for the isoelectric system (system containing the zwitterion). Moreover, the dissolution trend for the deprotonated amino acids was found to be cysteine> alanine> glycine> histidine, which was in line with the FTIR peak shift trend and the DFT bonding energy trend for the complexes. Furthermore, tests were done to improve gold dissolution, and these investigated oxidant type, amino acid effect, copper effect, oxidant concentration and pre-oxidation effect. Results showed that potassium permanganate was the best oxidant for glycine, alanine and cysteine, whereas hydrogen peroxide was the best oxidant for histidine. Furthermore, gold dissolution was enhanced with increasing amino acid concentration, copper concentration, and oxidant concentration, as well as the introduction of the pre-oxidation stage of pre-oxidising the pure gold. In addition, the electrochemical oxidation work also qualitatively supported the findings from the pure gold dissolution, showing that gold oxidation was enhanced by increasing variables investigated in the pure gold dissolution studies. Preliminary tests done on tailings leaching yielded low extraction leading to design experiments that improved the extractions. The Design of Experiment (DOE) was limited to alanine and glycine tests due to their promising ability in the pure gold dissolution and preliminary tailings tests. Results from the DOE showed a maximum 91.4% and 94.8% gold extraction upon using alkaline glycine and alanine, respectively at low solid liquid ratio after pre-oxidation of the tailing. Finally, the work gave a relationship between FTIR, DFT, gold dissolution and electrochemical oxidation of gold followed by proposing a mechanism for this work. The mechanism showed that potassium permanganate dissolved Au to Au+ in the pre-oxidation stage which could be a promising pretreatment method.

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The botanist from Belvidere: the living legacy of Augusta Vera Duthie (1881-1963)

(Elsevier B.V., 2025-04-25) Fourie-Basson, Wiida; Hills, Paul; Dreyer, Leanne L.

Here we review the life, career, botanical contribution and legacy of the founder of the Botany department at Stellenbosch University, Augusta Vera Duthie. We briefly introduce her, outline her background and personal life, as best as could be reconstructed from the few available publications and documents on her life. We then shift our focus to her long, often uphill, yet most impressive establishment and development of the Botany department at Victoria College (which later became Stellenbosch University). All attempts were made to highlight innovative initiatives she embarked upon to secure funding to grow the department, to the extent that she eventually managed to found the Stellenbosch University Herbarium and its associated library, the Stellenbosch University Botanical Gardens, and ultimately a fully functional Botany department, complete with lecturing facilities and laboratories. Reconstructing this chapter of her life relied heavily on a treasure trove of documents and letters held in the Stellenbosch University Library's Special Collections. The paper next briefly reviews her botanical contribution, focussing particularly on her work on the lowland flora of Stellenbosch. Again, documents, letters and photographs held in the Special Collection and Stellenbosch University Archives help illuminate her contributions as a botanist. We conclude by reviewing the different components of her rich legacy, and how most of these initiatives are being maintained to this day. Here we place a fairly strong emphasis on the Duthie reserve, and the ongoing conservation efforts to conserve this precious fragment of veld, the last remaining home to the critically endangered Haemanthus pumilio.

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Elucidating mechanisms that underpin aphid-plant interactions

(Stellenbosch : Stellenbosch University, 2024-12) Swiegers, Hendrik Willem; Botha-Oberholster, Anna-Maria; Foyer, Christine Hellen; Stellenbosch University. Faculty of AgriSciences. Dept. of Genetics & Institute of Plant Biotechnology.

Aphids are global pests of both crop and ornamental plants. Aphid infestations of crop plants result in yield losses through nutrient depletion and the spread of viruses. Although often effectively controlled by traditional chemical insecticides, these have deleterious effects on both the environment and human health. As such the use of insecticides have been restricted in some parts of the world. Secondly, many aphid populations have developed resistance to various insecticide classes. Host plant resistance offers an alternative to control aphid pests, however as with other control methods, aphids often overcome host resistance through the development of virulent biotypes. The aim of this project was to investigate the aphid-plant interaction by firstly examining differential gene regulation of aphid and host using virulent and avirulent Diuraphis noxia (Russian wheat aphid) biotypes feeding on a resistant Triticum aestivum (bread wheat) cultivar containing the D. noxia resistance gene, Dn7. The virulent D. noxia biotype SAMv2 exhibited distinct gene expression compared to the genealogically linked avirulent SAl, suggesting adaptations to overcome host resistance. SAMv2 upregulated transcripts implicated in detoxification (e.g. L-xylulose reductase) as well as other transcripts of unknown function. Transposable elements were highly active in all biotypes and to a lesser extent, epigenome modifying enzymes, potentially contributing to rapid adaptation to its host. T. aestivum responded to aphid feeding with jasmonic acid signalling and terpene biosynthesis. However, virulent SAMv2 appeared to modulate these defence mechanisms as monoterpenoid and diterpenoid biosynthesis were only upregulated following feeding by avirulent biotypes SAS and SAl, respectively. It was also found that the strigolactone synthesis gene, CYP711A1 was upregulated following feeding of biotype SAS. Secondly, the effect of elevated CO2 and strigolactones on Pisum sativum (pea) susceptibility to Acyrthosiphon pisum (pea aphid) were investigated. A. pisum performed better on strigolactone synthesis and signalling P. sativum mutants while [CO2] had no effect on aphid fecundity. The lower gibberellic acid levels observed in the strigolactone mutants were significantly correlated with increased A. pisum fecundity. Lastly, the function of cuticle protein, CpRRl-8, in the formation of virulence in D. noxia was also investigated. This work provides a foundation for developing more effective and sustainable aphid control strategies. Future research building on these findings will continue to uncover the dynamics of aphid-plant interactions and contribute to the development of resilient agricultural systems.

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A computer vision framework towards automated scene understanding & analysis

(2025-03) Sarah-lee de Greeff

It is well-known that recent advancements in the domain of artificial intelligence and the increased capability of computer hardware have significantly advanced the field of computer vision – a field of study which enables computers to “see” and extract meaningful information from visual inputs, similar to human perception. A prominent application area within the domain of computer vision is scene understanding. Various powerful approaches towards scene understanding employ computer vision tasks to extrapolate semantic information about scenes, allowing computers to understand relationships between objects and their environments. Such computer vision tasks include object detection, recognition, tracking, pose estimation, and contextual reasoning. Most computer vision algorithms are deep learning based approaches but differ significantly in architecture. The computer vision tasks investigated in this thesis utilise architectures consisting of backbone, neck, and head architecture as well as alternative transformer architectures. Although computer vision applications are diverse, there remain fields that have not yet fully benefited from these developments. One such field is energy auditing – a process undertaken to evaluate and improve the energy management of buildings. In this thesis, a proof-of-concept framework is developed, capable of extracting information regarding appliances present in a given building scene or environment by employing object detection and object tracking tasks. The objective of the proposed framework is to train various object detection models and recommend the best-performing model for further implementation, in conjunction with object tracking models, to analyse video footage of environments needing to be audited. The framework facilitates the processing of raw data, training of object detection models with respect to the proposed data, and the deployment of the trained model with respect to unseen video footage. A structured literature review is conducted in this thesis to investigate the pertinent literature related to computer vision applications within the energy auditing domain. The fundamentals of deep learning, computer vision and energy auditing are also explored. The proposed framework is first applied to a subset of a publicly accepted benchmark dataset to verify its correct functioning. Subsequently, to further assess the framework’s performance and applicability, it is applied to a novel case study dataset provided by an industry partner, containing images of appliances common in an educational institution. The framework facilitates hyperparameter tuning to determine the best parameters for each model being trained. The best-performing model, RTDeTR, is then utilised to detect and track appliances of interest, providing information regarding the number of appliances present. The information attained by the models is essential for the environment’s energy consumption computation.