Collection D

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Flood frequency analysis – Part 2: Development of a modified plotting position
(South African Water Research Commission., 2022-04-27) Van der Spuy D; Du Plessis JA
The original plotting position concept was suggested more than a century ago. Since then, many alternative plotting position approaches have been developed. Despite a general lack of agreement around which plotting position is theoretically ‘correct’ and the ‘best’ to use, all plotting positions fail to adequately address outliers and data of similar magnitude. Hydrologists generally fail to acknowledge that the plotting position primarily offers an informative display of data, against which distributions can be compared, rather than an absolute measure of probability. This paper does not intend to challenge any of the many lengthy theoretical mathematical arguments, utilised to ‘prove’ why one plotting position is superior to the others. These theoretical arguments may very well be valid for a ‘population’ of flood peaks – the reality, however, is that hydrologists are confronted with the challenge of analysing very limited ‘samples’ of the population. Consequently, the plotting position issue demands a more pragmatic approach, rather than a purely theoretical approach. This paper illustrates various problems with existing plotting position techniques in use and offers an alternative approach and a more sensible plotting position technique, using Z-scores and referred to as the Z-set PP, against which distributions can be checked. The study further illustrates how effectively the Z‑set PP deals with outliers and its robustness with various record lengths. Although derived from a study of flood peak data obtained from South African flow-gauging sites, it is deemed that it will be universally applicable.
Huwelikstevredenheid en vryetydsbesteding
(Faculty of the Humanities, University of the Free State, 2002) Viljoen, Hendrik; Greeff, Abraham
The aim of this study was to investigate patterns in leisure activities and their relation to marital satisfaction. A biographical questionnaire, a leisure activity questionnaire and two sub-scales of the Enriching and Nurturing Relationship Issues, Communication and Happiness (ENRICH) scale were completed independently by 35 married couples with adolescent children. The results indicated a significant positive relationship between marital satisfaction and contentment with the use of leisure time in both joint and individual-and-joint leisure activities. These results have important implications for premarital guidance, the enrichment of married life and marriage counselling.
INH preventive therapy (IPT) in HIV-infected south African children
(AOSIS, 2011) Cotton, Mark F.
HIV-infected children have a high risk of acquiring tuberculosis. The World Health Organization (WHO) has released isoniazid preventive therapy (IPT) recommendations for adults and children living with HIV, based on efficacy studies, mainly in adults. Data from children appear conflicting. IPT guidelines for children were developed in response to WHO guidelines at a local meeting, followed by discussions. IPT should be given to all HIV-infected children after exposure to a source case if treatment for active disease is not required. For children whose mothers' HIV status was known antentally, when tuberculosis has been actively excluded in mothers and at infant follow-up, and when infants have commenced antiretroviral therapy in the first 3 months of life, IPT is not required. Otherwise, all infants and children should be given IPT for 6 months once active tuberculosis has been excluded.
International registry on aortic balloon occlusion in major trauma: Partial inflation does not improve outcomes in abdominal trauma
(Elsevier, 2023-08-30) Paran Maya; McGreevy, David; Horer. Tal M; Khan, Mansoor; Dudkiewicz, Mickey; Kessel, Boris; the ABO Trauma Registry research group
Background Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method for temporary hemorrhage control used in haemodynamically unwell patients with severe bleeding. In haemodynamically unwell abdominal trauma patients, laparotomy remains the initial procedure of choice. Using REBOA in patients as a bridge to laparotomy is a novel option whose feasibility and efficacy remain unclear. We aimed to assess the clinical outcome in patients with abdominal injury who underwent both REBOA placement and laparotomy. Methods This is a retrospective study, including trauma patients with an isolated abdominal injury who underwent both REBOA placement and laparotomy, during the period 2011–2019. All data were collected via the Aortic Balloon Occlusion Trauma Registry database. Results One hundred and three patients were included in this study. The main mechanism of trauma was blunt injury (62.1%) and the median injury severity score (ISS) was 33 (14–74). Renal failure and multi-organ dysfunction syndrome (MODS) occurred in 15.5% and 35% of patients, respectively. Overall, 30-day mortality was 50.5%. Post balloon inflation systolic blood pressure (SBP) >80 mmHg was associated with lower 24-h mortality (p = 0.007). No differences in mortality were found among patients who underwent partial occlusion vs. total occlusion of the aorta. Conclusions Our results support the feasibility of REBOA use in patients with isolated abdominal injury, with survival rates similar to previous reports for haemodynamically unstable abdominal trauma patients. Post-balloon inflation SBP >80 mmHg was associated with a significant reduction in 24-h mortality rates, but not 30-day mortality. Total aortic occlusion was not associated with increased mortality, MODS, and complication rates compared with partial occlusion.
A novel method (FotoMaster) of documenting endosocopic surgical procedures
(Elsevier, 2000) Kruger, Thinus F.; Van der Merwe, Jacobus P.; Marino, Horacio; Hoogendijk, Christiaan F.; Du Toit, Thomas C.
Obesity is South Africa’s new HIV epidemic
(South African Medical Association, 2024-03) Chandiwana, Nomathemba; Venter, W D Francois; Manne-Goehler, Jennifer M; Wade, Alisha; le Roux, Carel W; Mbalati, Nzama Lawrence; Grimbeek, Angelika; Kruger, Petronell; Montsho, Eunice; Zimela, Zukiswa; Pillay Yogan; Dave, Joel A; Murphy, Angela; Goldstein, Sue; Hofman, Karen; Mahomedy, Sameera; Thomas, Elizabeth; Mrara, Busi; Wing, Jeff; Lubbe, Jeanne; Koto, Zack; Conradie-Smit, Marli; Wharton, Sean; May, Wayne; Marr, Ian; Kaplan, Hilton; Forgan, Mariam; Alexander, Graham; Turner, John S; Fourie, Gina; Hellig, Jocelyn Ann; Banks, Mandy; Ragsdale, Kim E; Noeth, Marisa; Mohamed, Farzahna; Myer, Landon; Lebina, Limakatso; Maswime, Salome; Moosa, Yunus; Thomas, Teressa Sumy; Mbelle, Mzamo; Sinxadi, Phumla; Bekker, Linda-Gail; Bhana, Sindeep; Fabian, June; Decloedt, Eric; Bayat, Zaheer; Daya, Reyna; Bobat, Bilal; Storie, Fiona; Goedecke, Julia H; Kahn, Kathleen; Tollman, Stephen; Mansfield, Brett; Siedner, Mark J; Marconi, Vincent C; Mody, Aaloke; Mtshali, Ntombifikile Nokwethemba; Geng, Elvin; Srinivasa, Suman; Ali, Mohammed K; Lalla-Edwards, Samanta; Bentley, Alison; Wolvaardt, Gustaaf; Hill, Andrew; Nel, Jeremy
World Obesity Day is on 4 March 2024, and our nation needs to pay attention. As with the HIV epidemic in the 1990s, we are facing a calamitous threat to the health of the population that has been ignored for too long. Weight-related diseases have eclipsed tuberculosis (TB) and HIV as leading causes of morbidity and mortality. Over two-thirds of South African (SA) women are overweight or are living with obesity.[1] For example, type 2 diabetes, stroke and heart disease, conditions all directly linked to the disease of obesity, account for three of the top four causes of death nationally and incur massive health system costs.[2,3] Moreover, excess weight gain has deleterious effects far beyond cardiovascular disease risk, with evidence strongly linking it to poor pregnancy outcomes, cancer, liver and kidney disease, mental illness, and sleep disorders.[4,5]. As with HIV in the early 2000s, tools to prevent and treat obesity are available, but too often are being ignored or obfuscated through government inaction, industry interests, and societal inertia. Also, as with HIV, SA has waited too long to convert effective interventions into effective public health strategy. Instead, we remain trapped in a cycle of apathy while blaming and stigmatising those affected. The medical establishment has not always been an ally in combating the obesity health emergency.[6] A poor understanding of the physiology of the disease, the endocrinological complexity of fat tissue, and the contribution of diet and exercise to weight gain has led healthcare providers to preach the common refrain of 'eat less and move more'. This serves to further perpetuate shame and stigma for those with the disease, even as it is now well understood to be ineffective alone for most of those affected.[7] Unsuitable weight loss advice contributes to confusion and anxiety for individuals with obesity, and in turn allows a diet, exercise and supplement industrial complex to thrive with minimal regulation.[8] But it is not too late for SA to implement an effective response to this established disease crisis. There are two important next steps. First, to apply the lessons from the HIV epidemic to reduce obesity-related stigma and facilitate widespread access to novel anti-obesity therapies using a public health approach; and second, to establish robust advocacy efforts that ensure that structural determinants of the disease, including food supply and the built environment, promote, rather than undermine, health. Much as combination therapy was a game changer for the HIV response, modern obesity medicine has demonstrated that novel medications and/or surgery are critical elements to achieve sustained weight loss and improved health outcomes.[9] For example, new classes of medications, such as the glucagon-like peptide (GLP)-1 receptor agonists, effectively control the disease, improve glycaemic control and reduce cardiovascular events, but are currently prohibitively expensive, prone to massive repeated supply shortages, and unavailable from state clinics and most medical aids.[9,10] SA is uniquely positioned to build upon the success of HIV and TB programmes to change this situation, by including simplification of access alongside generic manufacture at scale to facilitate price reduction. Notably, these interventions do not conflict with lifestyle recommendations, with recent evidence suggesting greater efficacy when these drugs are used in combination with lifestyle changes. The Standard Treatment Guidelines and Essential Medicines List currently contains no approach to the disease of obesity, and medication and surgical approaches were removed from the 2023 National Obesity Strategy, which barely mentions treatment, apparently owing to cost.[12] Obesity science is also teaching us how biomedical interventions are unlikely to be sufficient to tackle this epidemic alone. The obesogenic environment - structural societal conditions including both our food system and our built environment - is an important driver of the rise in obesity levels in the past 40 years in SA and elsewhere.[13-15] For example, the introduction of ubiquitous, cheap, highly and ultra-processed food and sugar-sweetened beverages, offered in slick venues and spaza shops accompanied by marketing campaigns often aimed at children, alongside a built environment that hinders sufficient physical activity, are major driving forces.[13,14,16] Focusing on our food supply, facilitating access to a diversity of affordable fresh, healthy, unprocessed food and the means to prepare it, and ensuring that the public is aware of the dangers of highly processed and ultra-processed food, is a necessary step.[17] It is highly unlikely that these systematic changes will be possible without firm government and regulatory intervention. Profit margins on heavily processed goods are far higher than on their less packaged counterparts, and powerfully resourced industries oppose such action, including opposition to even the most tentative steps around regulating sugary drinks and, more recently, promotion of food labelling.[12,18-20] One chilling difference from HIV is that the viral vector did not have a massive unregulated marketing machine behind it. Distressingly, there has been little sign of urgency on the part of government to take up the issue of food advertising, quality and affordability, and some of these industries clearly have the ear of senior officials, as in other countries.[18]. Debates on where to focus resources, programming, and attention on the prevention or treatment of clinical obesity are also reminiscent of the early HIV epidemic. Then, many prevention advocates regarded people with HIV as sad casualties of failed prevention programmes, too expensive and complex to treat. The language 'medicalising a social problem' has similarly started to creep into the discourse about obesity and its management, occasionally with a moral touch of 'they brought it on themselves'.[7] Allowing this language to persist would be a dreadful mistake. To destigmatise obesity, and effectively combat the obesity epidemic, it will be important to maximise the use of all prevention and treatment strategies simultaneously. The activist and medical communities were critical in advocating for the introduction of antiretroviral drugs and provision of healthcare that allowed individuals with HIV to live healthy, productive lives. We think that we have a moral imperative to advocate just as vigorously for individuals with obesity (Table 1). It is past time for our government and medical community to develop a laser-like focus on responding to the disease of obesity. Doing this will require policy, legislation, programming, and funding actions that will both facilitate access to innovative medical tools for obesity and deliver these in an environment that promotes healthy food choices and active lifestyles accessible to all. SA's HIV programme is often held up as the global model, thanks to decades of health activism, community engagement and science-based policy, along with government resources and commitment. Our established obesity epidemic now demands the same energy, commitment and focus from all of us.
Optimal design of intermittently operated subsonic-supersonic ejectors
(South African Institution of Mechanical Engineers, 2002) Pienaar, D. v V.
The optimal design for maximum run duration of intermittently operated subsonic-supersonic air-air ejector pumps of fixed geometry was investigated using an inviscid one-dimensional model of the mixing chamber. The study was confined to the case of matched static pressures of the primary and secondary air streams. An empirical correction factor was applied to the ID results in order to take approximate account of the two-dimensional velocity distributions at the inlet and outlet of the mixing chamber and of viscous shear forces. Optimisation of both the primary and secondary Mach numbers was found to yield significantly longer run durations than when the secondary is flow is sonic and just the primary Mach number is optimised. The most pronounced advantages of optimising both the primary and secondary Mach numbers were obtained in the range of high ejector performance. The main advantage is that an optimised ejector is physically smaller, and requires a smaller storage vessel than one that is not optimised.
Outcomes of surgical patients in a tertiary ICU with incidental COVID-19 in comparison with COVID-19 naïve patients
(Association Of Surgeons Of South Africa, 2024-12) Parker M; Mia I; Ahmed N; Van der Westhuizen V; Diayar A; Buitendag J
BACKGROUND: COVID-19 was first identified in Wuhan, China, in December 2019, where it spread over a wide geographic area until it reached the status of a pandemic in 2020. We postulated that patients who were diagnosed with incidental COVID-19, and underwent surgery, did not have a worse outcome due to the COVID-19 virus compared to their counterparts who did not have the virus. METHODS: This retrospective study included surgical patients (COVID-19 incidentals and COVID-19 negatives) who were admitted to the surgical intensive care unit (SICU) at Tygerberg Academic Hospital between 1 May 2020 and 31 December 2021. RESULTS: The sample consisted of 578 patients. Forty-one (41) patients had incidental COVID-19 infection, and 537 patients were COVID-19 naïve. The mean age was 43.9 years (SD = 16.7 years; range = 13.0-82.0 years) and 181 (31.3%) were female. The rates of complications in patients with COVID-19 infection (7.3%) and those without (5.0%) were similar (p = 0.64). Grades of complications, as measured using the Clavien-Dindo classification were also similar between patients with and without COVID-19 infection (p = 0.19). The mortality rates of patients with COVID-19 infection (17.1%) and those without (13.6%) were similar (p = 0.53). CONCLUSION: This study demonstrates that surgery among asymptomatic PCR-positive patients was not associated with increased mortality or morbidity in the SICU. This also adds a valuable contribution to the growing body of literature regarding COVID-19 infections. Further prospective and multicentred studies are required to provide more robust results.
Pathology-supported genetic testing presents opportunities for improved disability outcomes in multiple sclerosis
(2023-05-17) Johannes, Clint; Moremi, Kelebogile E.; Kemp, Merlisa C.; Whati, Lindiwe; Engel- Hills, Penelope; Kidd, Martin; van Toorn, Ronald; Jaftha, Mariaan; Janse van Rensburg, Susan; Kotze, Maritha J.
Background: Lipid metabolism may impact disability in people with multiple sclerosis (pwMS). Methods: Fifty-one pwMS entered an ultrasound and MRI study, of whom 19 had followed a pathology- supported genetic testing program for more than 10 years (pwMS-ON). Genetic variation, blood biochemistry, vascular blood flow velocities, diet and exercise were investigated. Results: PwMS-ON had significantly lower (p < 0.01) disability (Expanded Disability Status Scale) than pwMS not on the program (1.91 ± 0.75 vs 3.87 ± 2.32). A genetic variant in the lipid transporter FABP2 gene (rs1799883; 2445G>A, A54T) was significantly associated (p < 0.01) with disability in pwMS not on the program, but not in pwMS-ON (p = 0.88). Vascular blood flow velocities were lower in the presence of the A-allele. Conclusion: Pathology-supported genetic testing may provide guidance for lifestyle interventions with a significant impact on improved disability in pwMS. Plain Language Summary This study investigated the role of a genetic variant that increases saturated fat absorption and may make people with multiple sclerosis (MS) more susceptible to disability progression. Of 51 people with MS, 19 had followed a program which includes normalization of blood test results and daily intake of unsaturated fatty acids for more than 10 years, while the others had not. The latter group had significantly greater disability than the people who had followed the program, suggesting that the unsaturated fatty acids modulated the effect of the genetic variant. Six MS cases are presented as examples, including a marathon athlete (Case 1) and a patient who showed a dramatic decrease in disability from being wheelchair-bound for 15 years to walking freely (Case 2). Executive Summary: • In order to investigate the conundrum of why some people with multiple sclerosis (pwMS) become disabled while others do not, a cross-sectional interdisciplinary study was initiated from 1996 to the present at Stellenbosch University, to record data into a database regarding genetic variations, blood biochemistry, diet and exercise. Pathology-supported genetic testing (PSGT), a practical method to apply personalized medicine, was implemented to elucidate potential modulation of genetic variations through lifestyle interventions toward prevention of disability in pwMS. • The Gknowmix.org database is used to translate information obtained from a comprehensive study into personalized reports containing guidelines for treatment of pwMS by clinicians and supporting healthcare professionals, which enables P4 medicine: participatory (patient), personalized (scientist), predictive (clinician) and preventive (dietitian). • In the present case–control sub-study, 51 pwMS and 25 controls volunteered for an ultrasound and MRI study. Of these pwMS, 19 had followed the PSGT lifestyle program for more than 10 years, which included normalization of blood biochemistry, dietary intervention and exercise, as well as daily intake of specific supplements (the Rapha Regimen) [3], including unsaturated fatty acids (omega-3 and evening primrose oil). • The 19 pwMS who had followed the program had significantly less disability (p < 0.01), as assessed with the Expanded disability status scale (EDSS), than those who had not followed the program (1.91 ± 0.75 vs 3.87 ± 2.32). Furthermore, in the pwMS who had not followed the program, a genetic variant of a lipid transporter which favors increased absorption of saturated fatty acids, FABP2 rs1799883 (2445G>A, A54T), was associated significantly (p < 0.01) with the EDSS, while in the pwMS who had followed the program there was no association (p = 0.88). There was no difference in allele frequency between pwMS and controls. • Ultrasound assessments showed that higher blood flow velocities in the right common carotid arteries and vertebral arteries were significantly associated with improved EDSS, while the FABP2 rs1799883 variant was associated with decreased blood flow. • In the pwMS, homocysteine was significantly inversely associated with folate intake (p < 0.01). In the controls, saturated/trans fat intake was significantly associated with BMI (p < 0.01). • Six MS cases selected randomly are presented to demonstrate how data integration was instrumental in elucidating how dietary unsaturated fat intake may modulate the effect of FABP2 rs1799883 toward prevention of disability in pwMS who followed the PSGT protocol over more than 10 years. Of these, Case 1 is a marathon athlete, and Case 2 showed a dramatic decrease in EDSS from 7.5 to 2.0 over more than 10 years.
Patterns of on-scene and healthcare system trauma deaths in the Western Cape of South Africa. World
(John Wiley & Sons Ltd, 2024-02-03) Finn, J; Dixon, J.M.; Moreira, F.; Herbst, C.; Bhaumik, S.; Fleischer, C.L.; Stassen, W.; Beaty, B.; Lourens, D.; Verster, J.; Fosdick, B.; Lategan, H.J.; De Vries, S.; Uren, G.; Wylie, C.; Steyn, E.; Geduld, H.; Mould-Millman, N.-K.
Background Injuries account for 8% or 4.4 million deaths annually worldwide, with 90% of injury deaths occurring in low- and middle-income countries. Inter-personal violence and road traffic injuries account for most injury deaths in South Africa, with rates among the highest globally. Understanding the location, timing, and factors of trauma deaths can identify opportunities to strengthen care. Methods This is a retrospective cross-sectional secondary analysis of trauma deaths from 2021 to 2022 in the Western Cape of South Africa. Healthcare system trauma deaths were identified from a multicenter study paired with a dataset for on-scene (i.e., prior to ambulance or hospital) trauma deaths in the same jurisdictions. We describe locations, timing, injury factors, and cause of death. We assess associations between those factors. Results There were 2418 deaths, predominantly young men, with most (2274, 94.0%) occurring on-scene. The most frequent mechanism of injury for all deaths was firearms (32.6%), followed by road traffic collisions (17.8%). On-scene deaths (33.2%) were significantly more likely to be injured by firearms compared to healthcare system deaths (23.6%) (p-value <0.01). Most healthcare system deaths within 4–24 h of injury occurred in a hospital emergency center. Among healthcare system decedents, half died in the emergency unit. Conclusions We identified a large burden of deaths from interpersonal violence and road traffic collisions, mostly on-scene. In addition to primary prevention, shortening delays to care can improve mortality outcomes especially for deaths occurring within 4–24 h in emergency centers.
Performance of rotor-only axial fans designed for minimum exit kinetic energy
(South African Institution of Mechanical Engineers, 2002) Van der Spuy, S. J.; Von Backstrom, T. W.
The major loss source in rotor-only axial fans is the kinetic energy associated with the axial and circumferential components of the exit flow. This paper investigated the aerodynamic and acoustic performance of two fans designed to produce minimum exit kinetic energy. The first was a general application fan and the second a low-noise fan with large-chord forward-swept blades. The fans were tested for fan noise and performance in accordance with BS 848. The low-noise fan was the quieter and more efficient of the two fans, whilst both fans were quieter and more efficient than an existing typical general application fan, of unknown design. The results underlined the importance of following a well-defined design methodology when designing rotor-only axial flow fans.
Quantifying the role of personal management style in the success of investment portfolios
(Operations Research Society of South Africa, 2002) Wagenaar, E. A.; Van Vuuren, J. H.
It is extremely difficult to quantify the effect of different management styles of portfolio managers upon the success of their portfolios. Various mathematical models in the literature attempt to predict the risk and returns of portfolios according to changes in the economic arena, but these models usually do not take into account the personal styles of portfolio managers. The aim of this paper is a modest attempt at quantifying the effect of different managerial styles upon decisions regarding portfolios. This is accomplished by the formulation of a mathematical performance index that portrays the influence of a portfolio manager's personal and managerial characteristics on the success of his portfolio.
Simulating The Driving and Charging of Electric Minibus Taxis: A Case Study for Stellenbosch
(IWACP, 2023) Pretorius, B. G.; Strauss, J. M.; Booysen, M. J.
The Global North is increasing the drive for the electrification of the mobility industry. In sub-Saharan Africa, however, the adoption is yet to pick up steam due to various other challenges in the region. The viability of converting the paratransit fleet (which consists mostly of minibus taxis) to electric vehicles (EVs) with current combustion-based operations is investigated by making use of simulation software, and EV-Fleet-Sim. This developed software simulates the driving and charging of operationally tracked taxis in the Stellenbosch area. A charging algorithm, as well as a simple battery model, was included in the simulation to provide a more accurate representation of the scenario. Most of the taxis were found to still complete their required trips with the specified battery size of 70 kWh. However, new methods would need to be found, such as including a mixed fleet with some petrol or diesel taxis, to assure a 100% trip completion rate. The grid impact per vehicle was found with an expected maximum load appearing between the hours of 08h00 and 10h00 of 22 kW per vehicle, which corresponds to the time after the morning peak traffic of getting people to work. Furthermore, a minimum number of chargers can be implemented which will not affect the trip completion rate of the taxis. This was found to be for 4 chargers per 17 taxis. Future work is left to the testing of various parameters to find optimal solutions as well as including home charging and failed trip classification.
STRATEGIC MANOEUVRING IN ZIMBABWEAN POLITICAL DELIBERATIONS:A PRAGMA-DIALECTICAL AND APPRAISAL THEORY APPROACH
(Stellenbosch : Stellenbosch University, 2025-03) Mutsvairo, Jack; Dlali, Mawande; Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of African Languages.
Political argumentation by Zimbabwean government ministers and Members of Parliament, and political party representatives during Question Time sessions and radio political interviews, respectively, is not yet fully explored. This study analyses and evaluates the strategic manoeuvring of by ministers and Members of Parliament during Question Time question-and-answer deliberations, and party representatives on Studio 7 radio political interviews. The study aims to contribute new insights to the nascent literature on pragma-dialectical and appraisal research on Zimbabwean political discourse. Using data from the Hansard and Studio 7 radio political interviews, I analyse the political argumentation of Zimbabwean politicians within the two subgenres of parliamentary and media discourses. I use the pragma-dialectical argumentation theory as the main theoretical framework when analysing Hansard extracts and radio interview transcripts, and the appraisal theory as a complementary theoretical framework to evaluate language use in radio interviews. After carrying out reconstructive transformations of raw Hansard data which result in analytic overviews, I then apply and evaluate the typologies of differences of opinions, standpoints, argument schemes, argumentation structures, prototypical argumentative patterns, and argumentative styles. I also explore the use of ad hominems by the arguers. In the case of radio transcripts, I establish analytic overviews and then appraise language use by party representatives for attitudinal positioning, stance-taking and intertextual positioning using the appraisal analytical tools of the attitude and engagement semantics. My findings indicate that ministers use either complex pragmatic argumentation or complex problem-solving argumentation in defence of their prescriptive standpoints as they are expected to explain and justify government policies. MPs use mostly simple argumentation (enthymemic arguments) and at times complex pragmatic argumentation due to the limitations imposed by institutional preconditions. Argumentation by example and symptomatic argumentation are the favoured argument scheme and argumentation structure respectively for many politicians. Prototypical argumentative patterns revealed that ministers use direct dialectical routes since they have the burden of proof. They use largely detached argumentative styles except when they deliberate on divisive issues. Generally, politicians try to manoeuvre strategically but there are times when they aim for effectiveness at the expense of being reasonable, and when they are opposition MPs, they are called out by ZANU PF MPs and the Speaker hence their strategic manoeuvring derails. Politicians use ad hominems and erotema as emotional appeals and framing devices for their putative and/or primary audiences when deliberating hotly-contested issues, such as sanctions, human rights violations and currency policies. Shona proverbs and idiomatic expressions, emotive language and intertextuality/heteroglossic formulations are some of the presentational devices exploited by politicians during deliberations.
A survey dataset to evaluate the changes in mobility and transportation due to COVID-19 travel restrictions in Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa, United States
(Elsevier, 2020) Barbieri, Diego Maria; Lou, Baowen; Passavanti, Marco; Hui, Cang; Lessa, Daniela Antunes; Maharaj, Brij; Banerjee, Arunabha; Wang, Fusong; Chang, Kevin; Naik, Bhaven; Yu, Lei; Liu, Zhuangzhuang; Sikka, Gaurav; Tucker, Andrew; Mirhosseini, Gaurav; Naseri, Sahra; Qiao, Yaning; Gupta, Akshay; Abbas, Montasir; Fang, Kevin; Ghasemi, Navid; Peprah, Prince; Goswami, Shubham; Hessami, Amir; Agarwal, Nithin; Lam, Louisa; Adomako, Solomon
COVID-19 pandemic has heavily impacted the global community. To curb the viral transmission, travel restrictions have been enforced across the world. The dataset documents the mobility disruptions and the modal shifts that have occurred as a consequence of the restrictive measures implemented in ten countries: Australia, Brazil, China, Ghana, India, Iran, Italy, Norway, South Africa and the United States. An online questionnaire was distributed during the period from the 11st to the 31st of May 2020, with a total of 9 394 respondents. The first part of the survey has characterized the frequency of use of all transport modes before and during the enforcement of the restrictions, while the second part of the survey has dealt with perceived risks of contracting COVID-19 from different transport modes and perceived effectiveness of travel mitigation measures. Overall, the dataset (stored in a repository publicly available) can be conveniently used to quantify and understand the modal shifts and people's cognitive behavior towards travel due to COVID-19. The collected responses can be further analysed by considering other demographic and socioeconomic covariates.
Thermofluid analysis of an axial flux permanent magnet (AFPM) generator
(South African Institution of Mechanical Engineers, 2001) Wang, R.; Dobson, R. T.; Kamper, M. J.
In this article a lumped-parameter heat transfer model and an air flow model of a typical Axial Flux Permanent Magnet (AFPM) machine is presented. The application of the proposed models to an AFPM generator is described in detail. The calculated results are compared with the measurements taken from a prototype AFPM machine. The advantages and disadvantages of the approach are then outlined and conclusions drawn. The developed thermofluid model is shown to perform thermal analyses with reasonable accuracy.
Thermogravimetric study of the pyrolysis characteristics and kinetics of coal blends with corn and sugarcane residues
(Elsevier, 2013) Aboyade, Akinwale O.; Gorgens, Johann F.; Carrier, Marion; Meyer, Edson L.; Knoetze, Johannes H.
This paper investigates the non-isothermal thermokinetics of the co-pyrolysis of sugarcane bagasse and corn residue blended with coal. The individual devolatilization behaviour of each of the fuels obtained separately was compared with the behaviour of the biomass blends with coal at various mix ratios. Possible synergistic behaviour that points to the existence of chemical interactions during pyrolysis between the coal and biomass fractions of the blends could thus be quantified. Synergistic interactions in the blends resulted in higher than expected volatile yields. The interactions occurred between 300 °C and 500 °C, corresponding to the end of biomass devolatilization and the start of coal decomposition. Isoconversional kinetic analysis revealed that apparent activation energy values varied between 165–180, 162–190, 160–175, and 225–260 kJ mol− 1 for sugarcane bagasse, corn cobs, corn stover, and coal in the 0.1 to 0.8 conversion range. A comparison of E(α) for single fuels and coal-biomass blends gave further evidence of synergistic behaviour as demonstrated by larger variation in E(α) during the decomposition of the blends, compared to the individual fuels.
Towards a Cleaner Production of an Underutilised Legume, Bambara Groundnut
(IWACP, 2023) Mabitsela, M. MA; Hull, K.JA; Mavengahama, SB.; Phiri, E.E.; Booysen, M.J
Soilless cultivation systems such as aeroponics provide a more efficient, and clean food production of in areas where there is limited access to arable land for agricultural practices and drought-prone countries. The objective of this study was to evaluate the yield performance of seventy Bambara groundnut (BGN) landraces cultivated in aeroponics and compared with a traditional drip-irrigated hydroponic system with sawdust as a growing medium. The result showed that BGN landraces cultivated in aeroponics accumulated a high number of seeds, as compared to those landraces cultivated in hydroponics. However, BGN landraces cultivated in hydroponics recorded a high shoot dry weight and one hundred seed weight. The root length that could only be measured in BGN landraces cultivated in the aeroponics systems, showed that BGN root length can extend beyond one meter. Soilless cultivation systems with their high-water use efficiency have the potential of reducing production costs, thus making them accessible to farmers in countries where drought is a reality.

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