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Global disease burden of and risk factors for acute lower respiratory infections caused by respiratory syncytial virus in preterm infants and young children in 2019 a systematic review and metaanalysis of aggregated and individual participant data
No full textRationally modified SNXclass Hsp90 inhibitors disrupt extracellular fibronectin assembly without intracellular Hsp90 activity
No full textFundamental dermatology education of medical doctors at a regional hospital in Johannesburg South Africa
No full textTemporal and Spatial Reconciliation at Storm Mountain Diamonds Mine (Pty) Ltd
No full textA research report submitted in fulfillment of the requirements for the Master of Science, in the Faculty of Engineering and the Built Environment, School of Mining Engineering , University of the Witwatersrand, Johannesburg, 2025Storm Mountain Diamonds (Pty) Ltd’s Kao Mine has not been consistently achieving its production and grade targets, schedules, and mine call factor compared to the grade control model forecasts. These discrepancies can jeopardise the future of the mine and can lead to inaccurate decision making. Therefore, the aim of this study was to conduct temporal and spatial reconciliation at the mine. This was done to identify sources of variations in mineral resource volumes, tonnages, and grades at the mine. This reconciliation process is crucial for mines as it ensures the alignment of predicted and actual mineral resource extraction. The study was conducted for a period from September 2022 to August 2023. Various data collection methods were used including truck counts, plant weightometer, advanced vehicle analysis, and global navigation satellite systems to do the reconciliation process. Data such as truck tallies, face mapping, density measurements, exploration drilling data and monthly survey data were utilised in this research. It was found that the mine’s performance during the review period was below expectations. Average temporal and spatial compliance were found to be 8% (between tally and survey measurements) and 75%, respectively. September 2022 notably recorded the lowest spatial compliance of 44% primarily due to low equipment availability averaging 75%. Also, over- and under-breakages of up to 5m from the design were observed. This temporal and spatial underperformance was broadly caused by several reasons including poor blasting practices, unpredictable rainfall, human error and poor understanding of the orebody. It is recommended that the mine consider using more advanced survey equipment and data analytics technologies to collect and analyse data more accurately. The mine should also improve its accounting practices including spillage management on belt conveyors, maintaining low stockpile levels, regular calibration of weightometers and shifting to daily operational planning. It is also recommended that the mine must involve all relevant stakeholders in the reconciliation process to promote a culture of continuous improvement and accountability.MM202
Comparison of the effect of bacterial stimulation on the global epigenetic landscape and transcription of immune genes in primarily zoophilic members of the Anopheles gambiae complex Diptera Culicidae
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Business Models for Next-generation Communication Networks and Mobile Operators in Africa
No full textA research report submitted in fulfillment of the requirements for the Doctor of Philosophy, in the Faculty of Commerce Law and Management, Wits Business School, University of the Witwatersrand, Johannesburg, 2025This thesis uses an exploratory, sequential, mixed-methods research approach to: (1) identify and investigate the factors that limit existing business models for mobile network operators (MNOs) in facilitating next-generation communication networks (NGCNs); (2) develop a conceptual business model framework for NGCNs by addressing the shortcomings of existing business models and theoretical concepts in the strategic management and technological innovation literatures; and (3) evaluate the proposed conceptual business model framework for improving the business viability of MNOs. The study was conducted in four successive phases. Phases 1, 2 and 3 achieved the preceding three research aims. Phase 4 presented and interpreted the research findings. This study linked three main concepts in developing the business model framework: 5G network technologies, mobile network operators and theoretical concepts of management science. For the qualitative part of the study, semi-structured interviews were conducted using a case study approach and snowball sampling. Interview participants included top executives and senior managers from established mobile operators in Africa. The qualitative data analysis was conducted using reflexive thematic analysis and was implemented using the MAXQDA 24 software. The emerging themes and sub-themes as well as the proposed research prepositions were used in developing a conceptual framework and associated research hypotheses. The conceptual framework was quantitatively surveyed among employees of mobile operators in Africa that have commercialised 5G network services. Quantitative data analysis was performed using partial least squares structural equation modelling (PLS-SEM) and implemented using SPSS and SmartPLS software. Based on the quantitative findings, four of the six research hypotheses formulated were significant and clearly supported, while two were insignificant and therefore rejected. The main contribution of this thesis is the development of a business model framework for African MNOs deploying 5G and beyond networks. Theoretically, the study contributes by designing and examining business models for 5G networks and MNOs in Africa. Methodologically, the study contributes by combining inductive and deductive approaches in theory development, reflexive thematic analysis, PLS-SEM, and the use of MAXQDA24, SPSS and SmartPLS software in a single study. Empirically, the study contributes by highlighting practical implications and recommendations for practitioners, regulators, policy makers, and researchers.MM202
Cohort Profile Africa WitsINDEPTH partnership for Genomic studies AWIGen in four subSaharan African countries
No full textThe Effect of Improved Mineral Resource Management on the Net Present Value of the Camutue West Kimberlite Diamond Deposit in Angola
No full textA research report submitted in fulfillment of the requirements for the Master of Science, in the Faculty of Engineering and the Built Environment, School of Mining Engineering , University of the Witwatersrand, Johannesburg, 2025Angola is rated as a high-risk investor destination, fueling a high cost of equity rate. Bank loans are not easily secured for exploration programs with no proof of return from an established Diamond Resource. The Camutue West kimberlite was mined without a properly developed Diamond Resource model, and no investment was made in exploration drilling. The resource model was extrapolated to avoid capital spending. The exploration drilling program initiated in 2023 provided an opportunity to compare the extrapolated model to the actual result. It provided an opportunity to determine the value of the risk in avoiding capital spending compared to the cost of exploration drilling. Diamond valuation is a unique process that requires the final product to be in high quantities to determine the expected recovery price. Access to such samples could come at a very high cost if not exposed on the surface. This motivated the research to apply open pit optimisation techniques to assist exploration programs in adding value. Capital spent on the resource estimation, drilling and sampling program has been proven to increase the mine's value compared to the orebody extrapolation method. This proved that there was no replacement for a high- quality resource estimation, drilling and sampling program. Open pit optimisation techniques can be applied to reduce exploration drilling depth, assisting with quality control standards. These techniques also help generate earlier revenue for added value to the mine. Diamond mining companies must investigate the best techniques and drilling equipment to ensure high-quality exploration results. The success in achieving an optimal NPV result is highly dependent on an accurate geological model. Shareholders need to commit to proper exploration programs to achieve the best results for all stake holders involved.MM202
Slag Adherence Variation of Oxy Fuel Cutting Gases
No full textA research report submitted in fulfillment of the requirements for the Master of Science in Engineering, in the Faculty of Engineering and the Built Environment, School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, 2025Oxy-fuel cutting otherwise known as flame or oxygen cutting is a method used to separate steel sections during metal fabrication wherein the process slag produced may adhere to the bottom of the cut face. Adherent slag is a detrimental factor on the cut quality and subsequent post processing activities. In this study, the slag adherence during oxy-propane and oxy-acetylene cutting of 8 mm and 16 mm mild steel plates was investigated. The cutting tests were performed according to nominal Harris chart parameters, which were set at predetermined ranges to simulate workshop conditions. This was preceded by experimental testing which included visual observation, surface roughness, hardness, microscopic and elemental analysis. Utilising the Harris chart prescribed cutting parameters generally yields a good quality cut with no adherent slag. The slag is prone to adherence on the thinner plate cut with oxy-acetylene and the thicker plate cut with oxy-propane due to a higher content of free iron in the slags.MM202