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Item Optimizing Structures with Semi‑Rigid Connections Using the Principle of Virtual Work(Springer, 2018-04) Elvin, Alex; Strydom, JohnnieIn this paper, the virtual work optimization method (VWOM) has been generalised to consider structures with semi-rigid connections. The VWOM is an automated method that minimizes the mass of a structure with a given geometry, multiple deflection criteria, and load cases while adhering to design code requirements. In the optimization process, members are selected from a discrete database to meet all strength and stiffness criteria. Connections are modelled using rotational springs, allowing some moment transfer. The rotational stiffness of each connection can be varied from rigid to pinned. The example of a pitched roof frame is used to explain the method. Two case studies are considered: (i) (i) a three-storey two-bay and (ii) a four-storey three-bay office building. The VWOM produced results up to 26.7% lighter than results in the literature. Furthermore, the structures were optimized for a range of rotational stifness, where all connections in the structure were assumed to have the same rotational stiffness. Characteristic jumps in the optimized mass versus rotational stiffness were observed.Item Influence of socioeconomic status on changes in body size and physical activity in ageing black South African women(BioMed Central, 2018-04) Gradidge, Philippe Jean-Luc; Norris, Shane A.; Munthali, Richard; Crowther, Nigel J.Background: The increasing prevalence of obesity in sub-Saharan African women is not well understood, and black South African women in the region are particularly vulnerable. This study aimed to examine whether the relationship of socioeconomic status (SES) with changes in body mass index (BMI) and waist circumference (WC) is mediated by physical activity in ageing African women. Methods: In a longitudinal analysis of the 518 caregivers associated with the Birth to Twenty Plus study, the role of SES associated with 10-year changes in BMI and WC was tested using structural equation modelling (SEM). The degree of mediation of moderate-vigorous physical activity (MVPA) and sitting time in this association was also assessed. Results: The prevalence of obesity increased significantly from baseline to follow-up (p < 0.0001). In the SEM models, baseline SES had a direct positive effect on changes in BMI (β, 95% CI, 0.02 (0.005 to 0.04), and a direct negative effect on changes in MVPA (β, 95% CI, − 3.81 (− 6.92 to − 0.70). Baseline MVPA had a direct negative effect (β, 95% CI, − 0.002 (− 0.003 to − 0.0003) and indirect positive effect via change in MVPA (β, 95% CI, 0.01 (0.0001 to 0.001) on change in WC. Conclusions: Our study demonstrates the role and interaction of sociodemographic and behavioural predictors of obesity and suggests a multifaceted approach to management of the crisis in communities of ageing urban African women.Item Minimising the risk of thermally induced cracking in mass concrete structures through suitable materials selection and processing(Springer, 2018) Ballim, YunusThe hydration of cement is an exothermic reaction which generates around 300 kJ/kg of cement hydrated. In mass concrete structures such as dams and large foundations, this heat of hydration causes a significant rise in temperature in the internal sections of the concrete. If thermal gradients between the internal sections and the near-surface zone of the concrete element are sufficiently large, the thermal stress can cause cracking of the concrete. This cracking may cause functional or structural problems in the operation of the structure. In order to minimise the potential for such cracking, it is necessary to minimise the rate and amount of heat that is evolved, particularly during the early period of the hydration process. This can be achieved by design engineers and concrete technologists through judicious selection and processing of concrete-making materials. This paper presents the observations and results obtained over a number of years from adiabatic testing of concretes, computational modelling of temperature development in large concrete structures and direct temperature measurements in actual structures, with a view to understanding the effects of concrete-making materials on temperature development in concrete. The paper considers the effects of different types of rock aggregates, different types of Portland cement, fineness of grinding of the cement, the addition of supplementary cementitious materials and variations in the concrete starting temperature on temperature development in a large concrete element over time. The results indicate that using a coarser ground cement, adding significant amounts of supplementary cementitious materials and cooling the concrete mixture before placing has a more significant effect in reducing the risk of cracking than varying the aggregate type of the Portland cement type.Item Aphallia: a review to standardize management(2018-04) Gabler, Tarryn; Charlton, Robyn; Loveland, Jerome; Mapunda, EllenCongenital aphallia is a rare anomaly with little supporting literature and controversial management. The aim of this review is to assess the most recent literature with a focus on staged management of these cases. We performed a PubMed search of all English literature in the past 10 years using the term aphallia. Twenty-three articles were identified of which six were excluded. A further three papers meeting our criteria were found in the references to papers initially identified. We found that management can be staged in three phases: short, intermediate and long-term. We conclude that optimal short-term management centers on resuscitation and urinary diversion as necessary, intermediate-term management entails urethrorectal fistula division, urethrostomy and neophallus creation and long-term management results in successful neophalloplasty, urethroplasty, prosthetic implant and continued protection of the upper urinary tracts with a Mitrofanoff. All this within a multidisciplinary team ensuring shared decision-making with the patient and their familyItem Different adiposity indices and their association with blood pressure and hypertension in middle-aged urban black South African men and women: findings from the AWI-GEN South African Soweto Site(BioMed Central, 2018-04) Pisa, Pedro T.; Micklesfield, Lisa K.; Kagura, Juliana; Ramsay, Michele; Crowther, Nigel J.Background: To report associations between different adiposity indices [anthropometric and dual-energy X-ray absorptiometry (DXA) measures] and blood pressure (BP) and hypertension in urban black South African adults. Methods: Anthropometric and DXA whole body measures were performed on 1026 men and 982 women. Participants were classified as being hypertensive if they had a systolic BP (SBP) ≥ 140 mmHg and/or diastolic (DBP) ≥ 90 mmHg. Within each gender the relationship of adiposity with BP and hypertension risk was assessed using linear and logistic regression models respectively. Bivariate models were computed for each body composition variable. Furthermore, we computed a multiple regression model to illustrates how body composition parameters are associated with the outcome variables independent of each other. Results: The males were significantly taller and had a higher fat free soft tissue mass (FFSTM), DBP and socio-economic status, and were more likely to use tobacco and be hypertensive (48.0% vs. 38.8%). The females had higher body mass index (BMI), waist circumference (WC), fat mass (FM), subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), FM/ FFSTM ratio and body fat % than males. All body composition parameters were positively associated with hypertension. In both males and females, the FM/FFSTM ratio associated the strongest with hypertension illustrating the following odds ratios [males: 70.37 (18.47, 268.16) p ≤ 0.001; females 2.48 (0.86,7.21) p = 0.09]. The multiple regression model, indicated that the VAT and WC significantly associated with both SBP and DBP in the men and women respectively, whilst WC was the only significant predictor for hypertension. Conclusions: All body composition parameters were associated with hypertension and FM/FFSTM ratio showed the strongest relationship. It was reassuring that WC remains a useful measure of central adiposity that can be used as a risk indicator for hypertension if more sophisticated measures are not available. Furthermore, our data in part, implies that reducing abdominal adiposity in aging adults could contribute to reducing the risk of elevated blood pressure and hypertension.Item “People look and ask lots of questions”: caregivers’ perceptions of healthcare provision and support for children born with cleft lip and palate(BioMed Central, 2018-04) Hlongwa, Phumzile; Rispel, Laetitia C.Background: Clefting of the lip and/or palate (CL/P) is amongst the five most common birth defects reported in South Africa. The emotional impact on parents at the birth of their new-born with CL/P could affect parent-child relationships. In light of insufficient scholarly attention parental experiences and perceptions, this study reports on caregivers’ perceptions of health service provision and support for children born with cleft lip and palate in South Africa. Methods: The study setting consisted of 11 academic hospital centres situated in six of South Africa’s nine provinces. At each of the academic centres cleft clinic, five to ten parents or caregivers were selected purposively. Participants were interviewed, using a semi-structured interview schedule that elicited socio-demographic information, explored the family experiences of having a child with CL/P, and their perceptions of care provision and support services available. The interviews were analysed using thematic content analysis. Results: Seventy-nine participants were interviewed. Their mean age was 33.3 years (range 17–68 years). The majority of the parents were black African (72%), unemployed (72%), single (67%) and with only primary school education (58%). The majority of the children were male, with a mean age of 3.8 (SD = ±4.3) years. Five broad themes emerged from the interviews: emotional experiences following the birth of a child with cleft lip and palate; reactions from family, friends or the public; the burden of care provision; health system responsiveness; and social support services. Caregivers reported feelings of shock, anxiety, and sadness, exacerbated by the burden of care provision, health system deficiencies, lack of public awareness and insufficient social support services. Conclusions: The findings have implications for the integrated management of children with cleft lip and/or palate, including information to parents, the education and training of healthcare providers, raising public awareness of birth defects, and social support.Item Technological Competition and the World Order(Wits University (Southern Centre for Inequality Studies), 2025-04-04) D Nathan; S RahulThis paper deals with the role of competition and technological domination in changing the world order. It points out that there are constraints in the major Asian economies, which could hamper their ambitions of building technological dominance. Acknowledging that competition and monopolisation dominate the history of technological development in global capitalist history, the paper points to the necessity of international cooperation in meeting contemporary global challenges and staving off new forms of devastating warfare.Item Fighting Inequality: Progress Made Under G20 Brazil and the Priorities for South Africa(2024-12-05) David Francis; David FrancisIn the latter half of the 20th century, notable progress was made globally in addressing poverty and hunger, with significant reductions in poverty in large parts of the world. However, alongside these achievements came a rapid growth in inequalities of income and wealth within countries, alongside the persistence of inequalities in race and gender, among others.Item The policy we want: An economic policy for informal traders in South Africa(University of the Witwatersrand (Southern Centre for Inequality Studies), 2025-04-04) Siphelele Ngidi; David FrancisIn 2024, SCIS, in partnership with WIEGO (Women in Informal Employment: Globalising and Organising), embarked on a research and policy project to develop an economic policy for informal traders in South Africa. The project gathered insights from individuals actively working in the sector, offering valuable perspectives for policymakers and stakeholders seeking to improve the conditions of informal traders and strengthen the informal trading economy. Based on these findings, we identified actionable policy recommendations to help create a more conducive environment for informal trading. The results are presented in a policy brief structured around eight key pillars, titled “The Economic Policy We Want.”Item Alcohol industry involvement in the delayed South Africa Draft Liquor Amendment Bill 2016: a case study based on freedom of information requests(BioMed Central, 2025-03) Goldstein, Susan; Mitchell, Gemma; Siwela, Pfumelani; Diedericks, Aadielah MakerBackground South Africa is reported to have one of the highest per capita rates of alcohol consumption among drinkers globally, with alcohol harms exacerbating socio-economic inequalities in the country. The Draft Liquor Amendment Bill 2016 proposed new restrictions on alcohol advertising, availability, and liability of retailers and manufacturers for harm related to any contravention of the regulations. To date, the Bill has not progressed through the legislative process. The alcohol industry is known to use a diverse set of strategies to delay evidence-based policies globally. Methods We aimed to explore Bill-related activity by industry within the National Economic and Development Labour Council, a multi-stakeholder forum that assesses socio-economic policies before they reach parliament. On 06 July 2023 we made a Request for Access to Record, using form two of the Promotion of Access to Information Act (PAIA), no. 2 of 2000 to the National Economic and Development Labour Council for access to minutes of all meetings, reports, and any other publications related to the Bill between January 2016 and December 2022. Informed by Ulucanlar et al’s (2023) model and taxonomies of corporate political activity, we extracted data on industry Bill-related activity and thematically analysed key events, presented here as a narrative synthesis. Results We identified activity by 14 alcohol industry organisations related to the Bill between 2016 and 2022. Industry representation on five National Economic and Development Labour Council-related committees identified between 2017 and 2021 facilitated their involvement in Bill-related discussions and supported access to other government departments. Community representation was low in all committees compared to industry, labour, and government. Industry funded two socio-economic assessments of the Bill in 2017 and 2022, despite an independent socio-economic impact assessment having already been completed. The 2017 report delayed progress of the Bill, and the 2022 ‘re-evaluation’ was more critical of the proposed measures, with the differing conclusions attributed to different methodologies. During the covid-19 pandemic, industry used a ‘carrot and stick’ approach of legal threats and donations to attempt to move towards self-regulation via a social compact. The National Economic and Development Labour Council confirmed in 2023 that the social compact was unsuccessful. Conclusions Early ‘regulatory capture’ gave the alcohol industry the opportunity to shape assessment of the Bill within the National Economic and Development Labour Council. Our findings are in line with previous studies on corporate influence on policy globally, and support calls for a reassessment of the role and proportion of industry representation within the National Economic and Development Labour Council locally.