1. Academic Wits Research Outputs/Journal articles
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Item Lock-out, lock-in, and networked sovereignty: resistance and experimentation in Africa's trajectory towards AI(Brazilian Institute of Information in Science and Technology, 2024) Gagliardone, IginioThe conception of digital sovereignty has been associated, especially in the early stages of the diffusion of the Internet, with efforts to keep specific data and information outside of a state’s jurisdiction. AI sovereignty responds to an almost opposite logic, indicating the ability of a state to access and make use of data that are produced within its jurisdiction. These two strategies –which I refer to as lock-out and lock-in sovereignty –share some common roots (e.g. the attempt to protect and enhance specific cultural attributes recognised as important by a national community), but they also point to different technical, economic, and political characteristics needed to enforce one or the other type of sovereignty. The article examines key elements that set these concepts, and their implementation, apart and how they intersect with both existing and potential articulations of national sovereignty in Africa. In particular it opposes a negative –and still pervasive –definition of sovereigntyapplied to African states, based on the Westphalian ideal and “measuring the gap between what Africa is and what we are told it ought to be” (Mbembe 2019, p.26); and the possibilities disclosed by re-appropriating practices of “networked sovereignty” (Mbembe, 2016).Item Precipitation gradients drive high tree species turnover in the woodlands of eastern and southern Africa(Wiley, 2023-07) Davies, Robert W.; Ryan, Casey M.; Harrison, Rhett D.; Dexte, Kyle G.; Ahrends, Antje; te Beest, Mariska; Benitez, Lorena; Brade, Thom K.; Carreiras, Joao M. B.; Druce, Dave J.; Fayolle, Adeline; Finckh, Manfred; Godlee, John L.; Gonclaves, Francisco M.; Grundy, Isla M.; Hoche, T.; Holdo, Ricardo M.; Makungwa, Steve; McNicol, Iain M.; Mograbi, Penelope J.; Muchawona, Anderson; Muhate, Aristidies; Muledi, Jonathan; Pritchard, Rose; Revermann, Rasmus; Ribeiro, Natasha S.; Siampale, Abel; Staver, A. Carla; Syampungani, Stephen; Williams, Mathew; Swemmer, Anthony M.; Edwards, David P.Savannas cover one-fifth of the Earth’s surface, harbour substantial biodiversity, and provide a broad range of ecosystem ser-vices to hundreds of millions of people. The community composition of trees in tropical moist forests varies with climate, butwhether the same processes structure communities in disturbance-driven savannas remains relatively unknown. We investigatehow biodiversity is structured over large environmental and disturbance gradients in woodlands of eastern and southern Africa.We use tree inventory data from the Socio-Ecological Observatory for Studying African Woodlands (SEOSAW) network, cov-ering 755 ha in a total of 6780 plots across nine countries of eastern and southern Africa, to investigate how alpha, beta, andphylogenetic diversity varies across environmental and disturbance gradients. We find strong climate-richness patterns, withprecipitation playing a primary role in determining patterns of tree richness and high turnover across these savannas. Savannaswith greater rainfall contain more tree species, suggesting that low water availability places distributional limits on species,creating the observed climate-richness patterns. Both fire and herbivory have minimal effects on tree diversity, despite theirrole in determining savanna distribution and structure. High turnover of tree species, genera, and families is similar to turnoverin seasonally dry tropical forests of the Americas, suggesting this is a feature of semiarid tree floras. The greater richness andphylogenetic diversity of wetter plots shows that broad-scale ecological patterns apply to disturbance-driven savanna systems.High taxonomic turnover suggests that savannas from across the regional rainfall gradient should be protected if we are tomaximise the conservation of unique tree communities.Item Computer-based cognitive training for cognitive development of alcohol-exposed children in South Africa: a feasibility randomised control trial(Sage Publications, 2023) Louw, Jacobus; van Heerden, Alastair; Broodryk, Mandi; White, Liska; Olivier, Leana; Tomlinson, MarkChildren exposed to alcohol in utero may suffer from cognitive and physical sequelae. The most impactful damage in terms of daily functioning is to higher order cognitive functions involved in planning and goal-directed behaviour, referred to as executive functions. Cognitive training interventions are used as a remedial tool for executive function deficits but require implementation by professionals. For the South African context, where resources are limited, a tablet computer-based cognitive training game was developed. This study aimed to establish the feasibility of implementing and evaluating this intervention in South Africa for children exposed to alcohol prenatally. This was a three-arm feasibility randomised control trial comparing an alcohol exposed intervention arm, to an alcohol exposed control arm, and a non-exposed normative arm. Arm allocation was based on self-reported maternal alcohol use during a structured interview. To assess feasibility, we evaluated participant recruitment and barriers to implementation. Executive functions were measured at baseline and following intervention to evaluate the preliminary impact of the intervention. No significant differences were found between the three arms on the post-intervention assessments. The retention rate was acceptable for a randomised control trial; however, there was significant variance in the length of time spent playing the game overall. The majority of participants learned to play the game quickly and progressed through the difficulty levels. In conclusion, a full randomised control trial using the recruitment, randomisation and implementation method would be suitable in the South African context. The statistical outcomes of this trial do not support a full-scale randomised control trial of this intervention.Item Morphometry of the patellar tendon using a simple tracing method: a gold standard for anterior cruciate ligament reconstruction(Korean Association of Anatomists, 2023-06) Latiff, Sabiha; Olateju, Oladiran IbukunoluThe anterior cruciate ligament (ACL) is mostly damaged in sporting activities. To reconstruct the damaged ACL, a patellar tendon (PT) is often the most preferred graft due to its fast healing and bone integration i.e. bone-patellar tendon-bone graft. Suitability of the PT often depends on the morphometric profile of the tendon. This study reported on the harvestable surface area (SA) of the tendon using a simple tracing method. The PT of 79 adult formalin–fixed cadavers of South Africans of European Ancestry were dissected, and the margins of the PT were traced on a wax paper before the tracings were scanned. The SA, straight proximal width (SPW), curved proximal width (CPW), straight distal width (SDW), curved distal width (CDW) and length of tendon (LOT) from the digitized image of the PT was measured. In addition, the length of the lower limbs was measured to normalize the measurements. The results showed no significant side differences, and the measurements were not sexually dimorphic. A strong correlation was reported for SA vs. LOT, SPW vs. CPW and SDW vs. CDW for both sexes and sides. The presented morphological profile provides additional information on the usability of the graft and with respect to healing and recovery.Item Medicinal plants trade in Harare's urban markets diversity conservation status and economic significance(Biomed Central) Muvengwi, Justice ; Mbiba, MonicahBackground: Urban markets serve as crucial centres for trading traditional medicinal plants, yet there is limited research on the diversity, geographic origins, and socio-economic contributions of these plants. Therefore, this study aimed at understanding the species composition and diversity, conservation status, and economic importance of medicinal plants in urban markets of Harare, Zimbabwe, to provide insights into their sustainability and cultural significance. Methods: This study surveyed medicinal plant vendors in three major urban markets in Harare, Mbare, Highfield, and the Central Business District (CBD) in 2019 over a period of three months. Data were collected through semi-structured questionnaires to inventory medicinal plant species, document vendors' districts of origin, and assess harvesting practices. Species diversity was analysed using Shannon–Wiener and Simpson diversity indices, while Non-metric Multidimensional Scaling (NMDS) was used to compare species composition across markets. The informant consensus factor (ICF) was calculated to determine the level of agreement among vendors on the medicinal use of plant species. Results: A total of 64 medicinal plant species were identified, with Fabaceae being the most represented family. Sixty-one species were in the least concern IUCN Red List category. Key species with high use reports included Entada goetzei (62), Cassia abbreviata (58), Pterocarpus angolensis (40), and Albizia anthelmintica (31). Roots were the most sold plant part, followed by bark and leaves. Mbare exhibited the highest species richness (54), followed by Highfield (34), while the CBD recorded the lowest richness (23). Non-metric Multidimensional Scaling (NMDS) analysis revealed distinct differences in species composition among the three markets (R = 0.492), with Highfield displaying a unique suit of medicinal plant species. Vendors primarily originated and sourced their medicinal plants from eastern Zimbabwe, particularly Chipinge, highlighting a strong link between plant sourcing and geographic origin. The ICF was highest for gastrointestinal disorders (0.807), women’s health (0.778), sexually transmitted infections (0.746), and labour-related ailments (0.842). Medicinal plant trade contributed significantly to vendors' livelihoods, with monthly incomes ranging from US$150 to $300. Conclusion: This study underscores the high diversity of medicinal plants and their socio-economic importance in Harare’s urban markets. This shows that traditional medicine is still considered important in primary health care in the city of Harare. However, the reliance on distant districts (~ ≥ 100 km) for plant sourcing raises concerns about the possibility of unknowingly overharvesting.Item The "Ideal Man" : how gender norms and expectations shape South African men's masculinity sexual identities and wellBeingYoung, A.M.; Moji, Mpho; Duby, Z.; Tenza, Siyanda ; Atujuna, M.; Palanee-Phillips, Thesla ; Minnis, A. M. ; Montgomery, E.T.Dominant gender norms among South African males promote ideals of masculinity characterized by control, emotional stoicism, and power, which can impact overall health. This study explores South African men’s perceptions of the “ideal” man, societal expectations, and how sexual identities intersect with masculinity, health-seeking behaviors, and HIV prevention. We conducted 40 interviews with men who have sex with women and men who have sex with men, aged 18–35 years who resided in Johannesburg or Cape Town municipal areas. Participants described their idea of the "ideal man” as a provider, protector, and role model, though these ideals varied across.Item Impacts of African elephants and other environmental drivers on trees nested in by critically endangered whitebacked vultures(Nordic Society Oikos) Cook, Robin; Witkowski, Edward; Henley, MichelleThe decline of white-backed vultures Gyps africanus (hereafter termed vultures) across Africa highlights the need to understand their habitat and nesting requirements, especially in protected areas where African elephants Loxodonta africana can impact the trees in which vultures build their nests. Our study aimed to assess the impact that elephants have on trees containing vulture nests in the Associated Private Nature Reserves (APNR) of South Africa's savanna system through three separate but interlinked assessments. We first assessed the tree species used by vultures for nesting and compared their size and elephant impact scores between riparian and woodland habitats. We assessed how elephant presence or absence affects the size of Senegalia nigrescens, a key tree species, and compared vulture nests in an adjacent elephant-free area. Lastly, we modeled environmental factors influencing vulture nest and tree persistence using data from 2008–2020. Vultures utilised 10 tree species, with riparian trees supporting nests being significantly taller, with larger DBHs, and experienced lower elephant impact compared to woodland trees, which were more heavily impacted by elephants. Less robust species like S. nigrescens were more vulnerable to elephant damage, primarily bark-stripping, and less likely to host vulture nests. Our results show that vultures prefer the largest, least impacted trees for nesting, favouring those with greater stability and longevity. We suggest that although elephants influence the overall height range of trees to vultures, strong gusts of wind have a strong negative contribution on vulture nest persistence and that only a relatively small number of trees died during the 12-year study in comparison to fallen nests. We recommend further research into elephant impact thresholds on trees and vulture nest selection. Monitoring treefall and regeneration rates will help predict when vultures may face a shortage of suitable nesting trees.Item The Crystal and Molecular Structure of Nmethylephedrinium 4nitrobenzoate I II Racemic Mimic Part 5Bernal, Ivan; Lalancette, Roger A.Ephedrine is an ancient Chinese medicine drug used on patients with asthma, bronchitis and hay fever. In more recent times, it is used to prevent low blood pressure during anesthesia and to treat narcolepsy and obesity. It seemed important to understand the interaction of this drug with as large a variety of substrates as possible to get hints as to its modus operandi. It was, therefore, of interest that it appeared to crystallize as a Racemic Mimic in the form of its 4-nitrobenzoate derivative as determined by the cell parameters of that salt when it crystallized in both racemic and Sohncke space groups. Below, we describe the procedure used to prove that ephedrine belongs in that class and to illustrate the nature of the intra- and intermolecular interactions between the constituent moieties in that monoclinic (P21 and P21/c) pair. Both crystal structures,obtained from the literature, were determined at 123 K and refined, respectively, to R-factors of 3.73 and 5.51%.Item The life and mathematics of Ismail MohamedKikianty, Eder ; Nongxa, LoyisoIsmail Mohamed’s major contributions, which were in collaboration with Hermann Heineken, was to provide a procedure for constructing groups with prescribed characteristics. In particular, they constructed examples of non-nilpotent groups in which every subgroup is subnormal and nilpotent. These have become known as the Heineken–Mohamed groups. This construction led to settling a few questions posed, in the 1940s, by Kurosh and Cernikov in their survey of various generalisations of nilpotency. He also studied properties of series of subgroups of a group G that are constructed from arbitrary subgroups of automorphisms of a group.Item The direct and inverse problem for a class of entire functions related to sine type functionsMoller, ManfredFor a > 0 and nonnegative integers m and n the classes Aa m,n of entire functions are introduced. An entire function ω belongs to Aa m,n if ω is real on the imaginary axis and has the form (iμ)n−m+1ω(μ) = χ1(μ) cosμa + iχ2(μ) sin μa + (μ), where χ1 is a polynomial of degree n + 1 with leading coefficient i n+1, χ2 is a polynomial of degree at most n, and is small with respect to the other terms. When m = 0, these functions are sine type functions. The functions in Aa m,n have infinitely many zeros with explicitly given asymptotic behaviour, for which the first n + 1 terms in the asymptotics are determined by the coefficients in the polynomials χ1 and χ2. Conversely, any sequence of complex numberswith such an asymptotic representation determines a unique function from a class Aa m,n whose zeros are this given sequence. Some explicit formulas for the direct and the inverse problem are provided.