Research Articles (University of Pretoria)

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Monitoring coastal estuarine habitats for biodiversity along the temperate bioregion of South Africa
(Wiley, 2025-10) Campbell, Anthony; Adam, Elhadi; Adams, Janine B.; Barrenblitt, Abigail; Fatoyinbo, Temilola; Jensen, Daniel; Naidoo, Laven; Riddin, Taryn; Simard, Marc; Smith, Kyle; Thakali, Pati; Van Deventer, Heidi; Van Niekerk, Lara; Stovall, Atticus
Coastal wetlands provide critical ecosystem services, including the enhancement of biodiversity, carbon sequestration, and flood protection. Although these ecosystems have been mapped for country-level biodiversity typing, improved extent mapping is necessary to account for estuarine dynamics and improved reporting to the Kunming-Montreal Global Biodiversity Framework (GBF) by 2030. We achieved an overall coastal wetland accuracy of 90.7% (95% confidence interval: 90.2%–91.4%) utilizing a dense time series of very high spatial resolution (3 m) PlanetScope satellite imagery to map coastal wetlands with a combination of Random Forest to develop training data, U-Net convolutional neural networks, and a final decision tree to determine discrete ecosystem extents. Across the 84 mapped estuaries totaling 67,452 ha and 2,135 images, we mapped 9,131.1 ± 1,596.9 ha (13.5% of total estuarine functional zone extent) of salt marsh & reed beds and 1,718.6 ± 234.3 ha (2.5%) of Submerged Aquatic Vegetation (SAV). In addition to our earth observation analysis, we calculated tidal amplitudes and water level trends for 20 water level gauges across the region. We found tidal amplitude was a significant driver of salt marsh extent, explaining 33.6% of the variation (F (1,19) = 9.62, p = 0.005). We demonstrate a repeatable methodology for improved mapping of ecosystem zonation and utilize water level data to explore potential drivers of ecosystem distribution. Our method could be incorporated into a robust earth observation approach for reporting progress toward the goals of the/reporting to the GBF and Sustainable Development Goals (SDGs). PLAIN LANGUAGE SUMMARY Coastal wetlands provide many benefits to humans, including as habitat for a variety of species, accumulation of carbon in their soils, and protection from flooding and storm events. Global and regional maps of these ecosystems exist, but they lack precision in their identification of ecosystem zones. Improved maps could be used for improved reporting to international agreements and inform coastal management. We mapped three coastal wetland habitats to a high degree of accuracy (90.7%) utilizing a time series of commercial satellite data and machine learning algorithms. Across the 84 mapped estuaries totaling 67,452 ha, we mapped 9131.1 ± 1596.9 ha (13.5% of total estuarine functional zone extent) of salt marsh & reed beds and 1718.6 ± 234.3 ha (2.5%) of Submerged Aquatic Vegetation (SAV). We conducted additional analysis on how tidal amplitude, water level, and impervious surface influence the distribution of habitats in the region, finding that higher tidal amplitudes correlated with more salt marsh extent. Our methodology is repeatable and could improve the monitoring of these ecosystems in South Africa. KEY POINTS • We mapped coastal wetland habitats (salt marsh, reeds and sedges, and submerged aquatic vegetation) with a U-Net approach at >90% accuracy • We identified tidal amplitude as a major driver of salt marsh habitat, explaining 33.6% of the variation (F (1,19) = 9.62, p = 0.005). • Salt marsh was only 19.4% of coastal wetland extent, 40% of this extent was found within Knysna Estuary and Langebaan Lagoon.
Globale biodiversiteitsraamwerk vir varswatervleilande van Suid-Afrika : voorlopige berekening van die vordering om die restourasiemikpunt van doelwit 2 te bereik
(Suid-Afrikaanse Akademie vir Wetenskap en Kuns, 2025-07) Van Deventer, Heidi
AFRIKAANS : Die Nasionale Biodiversiteitsanalise van 2018 het bevind dat vleilande (riviermondings en varswatervleilande) die mees bedreigde van al die ekostelsels in Suid-Afrika is. Teen 2030 moet Suid-Afrika aan die Verenigde Nasies se Globale Biodiversiteitsraamwerk (GBR) rapporteer of Doelwit 2 bereik is, naamlik om 30% van gedegradeerde stelsels in die proses van herstel te hê. Hierdie studie het beoog om die voorlopige omvang as persentasie van varswatervleilande wat aan ekologiese ingrypings onderworpe was in verhouding tot die totale omvang van gedegradeerde varswatervleilande in Suid-Afrika te bereken. Ons het ook die persentasieomvang in verhouding tot eienaarskap van die gedegradeerde varswatervleilande en dié wat onder ekologiese restourasie is, bepaal. Die Werk vir Vleilandeprogram en die Werk vir Waterprogram se beskikbare data is ingesamel en met die Nasionale Vleilandkaart weergawe 6, gekombineer om die persentasies te bereken. Die meerderheid van Suid-Afrika se varswatervleilande (51%) is gemodelleer om degradasie te bepaal, met >2.0 miljoen hektaar van die 4 miljoen hektaar Suid-Afrikaanse vleilande wat impakte toon ten opsigte van veranderinge aan die hidrologiese siklus, waterkwaliteitsimpakte, fragmentasie en verlies van habitatte, voorkoms van indringerspesies en klimaatverandering, of ‘n kombinasie van hierdie impakte. Die 30% van Doelwit 2 beteken dus dat amper 613 136 ha van varswatervleilande teen 2030 onder ekologiese herstel moet wees. Ekologiese herstelprogramme het tot dusver slegs ongeveer 203 283 ha (10%) van Doelwit 2 bereik. Die meerderheid (82,8%) van vleilande is op privaat grond geleë, waarvan meer as die helfte gedegradeer is. Baie van die impakte op vleilande, asook die restourasieinisiatiewe wat deur die privaat sektor of individue uitgevoer word, word nie in hierdie berekening weerspieël nie. Monitering en kwantifisering van alle varswaterhabitatte is dus noodsaaklik om Doelwit 2 van die GBR teen 2030 te bereik. ENGLISH : The National Biodiversity Assessment of 2018 listed wetlands (estuaries and freshwater ecosystems) as the most threatened ecosystem of South Africa. By 2030, South Africa must report to the United Nations’ Global Biodiversity Framework (GBF) to which degree we have reached Target 2 that aims to have 30% of the extent of degraded ecosystems under restoration. This study aimed to calculate the preliminary extent as a percentage of wetlands that have been under ecological restoration interventions, relative to the total extent of degraded freshwater wetlands of South Africa. We also assessed the percentage of extent relative to ownership of the degraded wetlands and those that are under ecological restoration. Data released by the Working for Wetlands and Working for Water programmes were combined with the National Wetland Map version 6 as well as information on land ownership and protection level status of the country. The majority of the freshwater wetlands (51%) were modelled as degraded, with > 2 million ha of the 4 million ha of wetlands showed impacts resulting from various pressures, including changes to the hydrological cycle, water quality, fragmentation and degradation of habitats, climate change, or a combination of these pressures. The 30% GBF Target 2 requires that almost 613 136 ha of freshwater wetlands should be under restoration by 2030. The government’s two restoration programmes have reached only 203 283 ha (10%) of the desired target. The majority (82,8%) of freshwater wetlands is located on private land, of which the majority is degraded. Many of the impacts and none of the restoration interventions undertaken by the private sector or individuals are reflected. Monitoring and quantification of all freshwater habitats are therefore needed to attain the 30% extent target of the GBF.
Remote sensing monitoring of soil moisture for South African wetlands
(Water Research Commission, 2025-04) Van Deventer, Heidi; Naidoo, Laven; Le Roux, Jason; Blaauw, Ciara; Tema, Hebert
Surface soil moisture is an essential climate variable (ECV; https://gcos.wmo.int/en/essential-climate-variables/soilmoisture) which is monitored to inform our understanding of changes in the atmosphere and earth. Soil moisture is also an important indicator, in addition to vegetation and soil types, of the presence of a wetland.
Post-mortem interval estimation in the tropical climate of Southern Nigeria
(Taylor and Francis, 2025) Etoniru, Izuchukwu Stanley; Myburgh, Jolandie; Steyn, Maryna; Brits, Desiré
ABSTRACT : Post-mortem interval (PMI) estimation is the first step in the investigation of decomposing remains. The absence of locally derived methods, and a dearth of forensic experts, make PMI estimation difficult in Nigeria. This study aimed to assess decomposition rates in southern Nigeria and to derive formulae for PMI estimation by using quantitative variables, accumulated degree days (ADD) and total body score (TBS), using a pig model (n = 20). A longitudinal examination of TBS and ADD was conducted over 14 months, during the dry and wet seasons. Scatter plots between TBS and PMI, and TBS and ADD were used to show decomposition patterns and loglinear random-effects maximum likelihood regression was used to produce linear regression formulae for PMI estimation. Overall, decomposition progressed rapidly. Shorter PMIs were associated with more advanced decomposition when compared to studies in temperate regions. Despite similar average daily temperatures in the wet and dry seasons, there were marked differences in decomposition patterns between the seasons, with the wet season exhibiting more rapid decomposition rates. This demonstrates the importance of rainfall and humidity in decomposition rates. The derived regression formulae for ADD and PMI will provide a much-needed location-specific method for PMI estimation in Nigeria and regions with similar climates. RÉSUMÉ : L’estimation de l’intervalle post mortem (IPM) est la première étape de l’examen des restes en décomposition. L’absence de méthodes locales et le manque d’experts médico-légaux rendent difficile l’estimation de l’IPM au Nigéria. Cette étude avait pour objectif d’évaluer les taux de décomposition dans le sud du Nigéria et de dériver des formules pour l’estimation de l’IPM à l’aide de variables quantitatives, des degrés-jours cumulés (DJC) et du score corporel total (SCT), en utilisant un modèle porcin (n = 20). Un examen longitudinal du SCT et des DJC a été mené sur une période de 14 mois, pendant les saisons sèche et humide. Des diagrammes de dispersion entre le SCT et l’IPM, et entre le SCT et les DJC ont été pour démontrer les modèles de décomposition, et une régression linéaire aléatoire à effets maximaux a été utilisée pour produire des formules de régression linéaire pour l’estimation de l’IPM. Dans l’ensemble, la décomposition s’est avérée rapide. Des IPM plus courts ont été associés à une décomposition plus avancée par rapport à d’autres études menées dans des régions tempérées. Même si les températures quotidiennes moyennes étaient similaires pendant les saisons humides et sèches, il existait des différences notables dans les schémas de décomposition entre les saisons, la saison humide présentant des taux de décomposition plus rapides. Cela démontre l’importance des précipitations et de l’humidité dans le taux de décomposition. Des formules de régression linéaire pour les DJC et l’IPM ont été dérivées et fourniront une méthode adaptée à chaque site, très nécessaire pour l’estimation de l’IPM au Nigéria et dans les régions ayant des climats similaires.
Design thinking as a pedagogical approach for the Jam, a fast-paced cross-institutional programme with a focus on social justice
(Taylor and Francis, 2025) Nerantzi, Chrissi; Kioupi, Vasiliki; Malone, Cathy; McDonald, Damian; Mushonga, Tafadzwa; Vallance, Simon; Borde, Radhika; Rofe, J. Simon; Parsons, Megan; Roxby Wardle, Naomi; Michel-Villarreal, Rosario; Mack, Annalisa; Bezbaruah, Rishabh; Nyabundi, Agnetta Adiedo; Pullman, Charles
This contribution reports on the design phase of the Jam, a short, fast-paced, cross-institutional online programme over three days. Its focus is on social justice and specifically access, use and management of community space, as integral part of sustainability. This novel programme aims to enable learning, generate ideas to address complex issues, build connections and support diverse community members engage in cultural exchanges. Developed by the University of Leeds in collaboration with the University of Pretoria, ls14trust in Seacroft, and Mothong African heritage in Mamelodi, it brings together educators, professional services staff and students and the public in non-hierarchical ways to inspire new and different ways to interact and learn. We present an account of the design phase of the Jam, including an account of our institutional design context, an overview of literature on Jams and Jamming that informed our design of the Social Justice Jam: Spaces for Change 2024.
Why we should protect the high seas from all extraction, forever
(Nature Research, 2025-06) Roberts, Callum M.; Dyer, Emilia; Earle, Sylvia A.; Forrest, Andrew; Hawkins, Julie P.; Hoegh-Guldberg, Ove; Meeuwig, Jessica J.; Pauly, Daniel; Pimm, Stuart L.; Sumaila, Ussif Rashid; Rockstroem, Johan; Lynas, Mark
Exploitation of the high seas risks doing irreversible damage to biodiversity, climate stability and ocean equity. A consensus must be built now to save them.
Building the future of exercise oncology : current status of international workforce development and integration into standard cancer care
(Oxford University Press, 2025-09) Wonders, Karen Y.; Kennedy, Mary A.; Capozzi, Lauren C.; Lei, Yao; Pillay, Lervasen; Azevedo Voltarelli, Fabrício; Wiskemann, Joachim; Campbell, Anna M.
The complex requirements of people with cancer can impact the provision of safe, effective, evidence-based exercise prescription. Consequently, a range of essential competencies are required from the exercise oncology workforce. There is a global need for a standardized approach to the development of this workforce. By defining, standardizing, and training the workforce in essential competencies, this will enable various professionals to safely and effectively screen, access, design, and deliver appropriate exercise programs. Therefore, this is also a call for a global collaboration on the development of the exercise oncology workforce with special attention to assisting low- or middle-income countries with their increasing cancer burden and unique challenges, which may require unique context-specific strategies. The building of an appropriate internationally standardized workforce is essential in the provision of physical activity and exercise options as part of standard cancer care.
Improved class separation by GC x GC of volatile hydrocarbons with an unconventional increase in the second dimension plate number
(Elsevier, 2025-11) Potgieter, H.; Rohwer, Egmont Richard; Joubert, T.
Light petroleum fractions are produced during crude and synthetic oil refining processes and are upgraded to useful products in various markets. These fractions are upgraded using various refining processes, and the characterization of these fractions is essential for process control and ensuring final product specifications. These light fractions can be very complex and multidimensional gas chromatography (GC × GC) is used to characterise these complex samples. ASTM method D1319, Fluorescent Indicator Adsorption (FIA), is used routinely for the determination of the total volume percent of saturates, olefins and aromatics in petroleum fractions and is used in the certification of final gasoline products. There would be several advantages if chemical group-type separation for gasoline can be achieved on GC × GC. Even though excellent GC × GC chemical group-type separation has been achieved, the separation of ≤C6 aliphatics (alkanes, alkenes and cyclic alkanes) in light fuels like gasoline remains a challenge with insufficient resolution between these compounds. In this study, the GC × GC parameters for the optimum separation of the ≤C6 aliphatics were determined with group-type separation of light fuels in mind. The study showed that it is possible to achieve this separation under GC × GC wrap-around conditions whereby two modulations of analytes are moving through the second dimension column at any time, allowing for the use of 2 - 4 times longer second dimension columns. For the first time the optimum separation of the ≤C6 aliphatics were determined while maintaining good separation for the heavier hydrocarbons. Good GC × GC chemical group-type separation for gasoline samples was obtained with this method. Quantitative results, combined with bromine number analysis, compared well with the results obtained by the FIA method. HIGHLIGHTS • GC × GC parameters for the optimum separation of the ≤C6 aliphatics were determined. • Separation under GC × GC wrap-around conditions, allowing longer 2nd dimension columns. • GC × GC chemical group-type separation for gasoline samples obtained with this method. • This method potentially provides an alternative to the FIA method.
Neonatal antipredator tactics shape female movement patterns in large herbivores
(Nature Research, 2025-01) Atmeh, Kamal; Bonenfant, Christophe; Gaillard, Jean-Michel; Garel, Mathieu; Hewison, A.J. Mark; Marchand, Pascal; Morellet, Nicolas; Anderwald, Pia; Buuveibaatar, Bayarbaatar; Beck, Jeffrey L.; Becker, Matthew S.; Van Beest, Floris M.; Berg, Jodi; Bergvall, Ulrika A.; Boone, Randall B.; Boyce, Mark S.; Chamaillé-Jammes, Simon; Chaval, Yannick; Buyanaa, Chimeddorj; Christianson, David; Ciuti, Simone; Cote, Steeve D.; Diefenbach, Duane R.; Droge, Egil; Du Toit, Johan T.; Dwinnell, Samantha; Fennessy, Julian; Filli, Flurin; Fortin, Daniel; Hart, Emma E.; Hayes, Matthew; Hebblewhite, Mark; Heim, Morten; Herfindal, Ivar; Heurich, Marco; Von Hoermann, Christian; Huggler, Katey; Jackson, Craig; Jakes, Andrew F.; Jones, Paul F.; Kaczensky, Petra; Kauffman, Matthew; Kjellander, Petter; LaSharr, Tayler; Loe, Leif Egil; May, Roel; McLoughlin, Philip; Meisingset, Erling L.; Merrill, Evelyn; Monteith, Kevin L.; Mueller, Thomas; Mysterud, Atle; Nandintsetseg, Dejid; Olson, Kirk; Payne, John; Pearson, Scott; Pedersen, Ashild Onvik; Ranglack, Dustin; Reinking, Adele K.; Rempfler, Thomas; Rice, Clifford G.; Roskaft, Eivin; Saether, Bernt-Erik; Said, Sonia; Santacreu, Hugo; Schmidt, Niels Martin; Smit, Daan; Stabach, Jared A.; St-Laurent, Martin-Hugues; Taillon, Joelle; Walter, W. David; White, Kevin; Peron, Guillaume; Loison, Anne
Caring for newborn offspring hampers resource acquisition of mammalian females, curbing their ability to meet the high energy expenditure of early lactation. Newborns are particularly vulnerable, and, among the large herbivores, ungulates have evolved a continuum of neonatal antipredator tactics, ranging from immobile hider (such as roe deer fawns or impala calves) to highly mobile follower offspring (such as reindeer calves or chamois kids). How these tactics constrain female movements around parturition is unknown, particularly within the current context of increasing habitat fragmentation and earlier plant phenology caused by global warming. Here, using a comparative analysis across 54 populations of 23 species of large herbivores from 5 ungulate families (Bovidae, Cervidae, Equidae, Antilocapridae and Giraffidae), we show that mothers adjust their movements to variation in resource productivity and heterogeneity according to their offspring’s neonatal tactic. Mothers with hider offspring are unable to exploit environments where the variability of resources occurs at a broad scale, which might alter resource allocation compared with mothers with follower offspring. Our findings reveal that the overlooked neonatal tactic plays a key role for predicting how species are coping with environmental variation.
An economic order quantity model for imperfect and deteriorating Items with freshness and inventory-level-dependent demand
(South African Institute of Industrial Engineers, 2025-08-29) Coghlan, Deidre Ann; Adetunji, Olufemi; Sebatjane, Makoena; Kapya, Tshinangi Fabrice; tshinangi.kapya@up.ac.za
ENGLISH : The sale of many products is influenced by the characteristics of the products and the behaviour of the consumers. This is particularly true of food items. Consumers of most food items want them fresh; thus, while items that are edible but have lost some of their freshness might be sold, the demand usually drops, and the closer the expiry date, the lower the demand for such products. Another factor that is known to affect the sale of many items is the attractiveness of the stocking pattern. Seeing a large stock of consumable items tends to attract consumers; hence the stock level dependence of demand. An additional characteristic of such products is that they continue to deteriorate; thus affects both the quality and quantity of such items, as the overly deteriorated ones are removed from the stock of saleable items. Consequently, the stock level reduces owing to both demand and deterioration. This description fits many agricultural products such as fruits and vegetables. Another characteristic of such products is the possibility of their being imperfect when they are received, as some stock might be damaged by harvesting, handling, or transportation. In this research, we develop a mathematical model to determine the optimal lot size for an item having all these characteristics, with the profit function as the model objective. We used a case of banana as the numerical illustration. Sensitivity analyses of important model parameters were conducted to demonstrate the model’s robustness. The findings were that the date of expiry, the scale of demand, and the selling price of perfect products were the main constituents that affected their profitability. This model should find ready application in most stores where fresh consumable food items such as fruits and vegetables are managed.
Scoping review : factors, threats and opportunities of outsourcing maintenance activities in the South African pulp and paper industry
(South African Institute of Industrial Engineers, 2025-08-29) Maphanga, Wandile; Grobbelaar, Schalk; Peach, Rina Helena; Visser, J.K. (Jacobus)
ENGLISH : Outsourcing is a tool to realise the strategic intent of an organisation. Before outsourcing maintenance services, the maintenance manager should consider the relevant factors, opportunities, and threats. The study aimed to perform a scoping review of the applicable factors, opportunities, and threats in the pulp and paper industry. The review also aimed to determine whether there was a gap in the literature from a South African perspective. Scopus and Web of Science were used as databases to collect 21 articles published from 2002 to 2021. Using ATLAS.ti, 11 categories in these articles were coded, and Sankey diagrams were used to visualise the data. The percentage strength of the correlations indicated recurring themes in the literature. The results found strategy through targeted outsourcing of non-core activities (50%), supplier performance (53%), and employee impact (15%) to be critical factors. Cost reduction (42%) and access to vendor expertise (21%) were key opportunities, while poor supplier performance (29%) and loss of organisational know-how (33%) were key threats. As a recurring theme, outsourcing was found to be common to industries in Europe, Asia, and North America. Based on the findings of the scoping review, it was concluded that there was an opportunity to explore the local context. It was recommended to use the findings and to determine whether these factors, threats, and opportunities could be applied to the South African context.
Service innovation dynamic capabilities framework : a case of water utilities in South Africa
(South African Institute of Industrial Engineers, 2025-08-29) Shabangu, Luc; Letaba, Tshotleho Petrus
ENGLISH : South African water utilities’ capability to provide high-quality drinking water service is deteriorating, and the country faces a significant problem with continuous water supply because of rising water demand caused by high population growth, industrialisation, and agricultural activities. A quantitative methodology was used to collect and analyse data. Then a framework for service innovation’s dynamic capabilities was developed to address the deteriorating service capabilities in South African water utilities. The study's contribution is this framework, which integrates ordinary capabilities, managerial dynamic capabilities, service innovation capability, and new and emerging technological concepts to address the water supply problem.
Six-month trajectory of physical function in ICU survivors: Experience from an Eastern Cape centre
(AOSIS, 2025-08-12) Van der Merwe, Elizabeth; Stroud, Louise; Sharp, Gary; Van Vuuren, Noline; Paruk, Fathima
BACKGROUND : Physical impairment affects up to 60% of intensive care unit (ICU) survivors due to factors such as ICU-acquired neuromuscular weakness (ICU-AW), chronic pain, deconditioning and reduced organ and metabolic function. This impairment is linked to lower health-related quality of life (HRQOL). OBJECTIVES : Our study aimed to assess physical impairment and HRQOL among critically ill patients post hospital discharge. METHOD : Intensive care unit survivors were assessed six weeks and six months post hospital discharge. Physical performance was evaluated using the six-minute walk test (6MWT) and muscle strength with the Medical Research Council (MRC) score. Patients’ HRQOL was determined using the Rand Short Form-36 questionnaire. RESULTS : A total of 107 patients (median age 42 years), including 50% with COVID-19, completed the 6-month follow-up. Although significant improvements were observed, 53.5% walked less than 80% of the predicted 6MWT distance at six months, with females disproportionately affected. Poor physical performance was associated with lower physical and mental HRQOL. Pain interfering with activities was reported by 26.2% at six months. Only 2% met full criteria for ICU-AW at six months. By six weeks, only 15% had attended physiotherapy. CONCLUSION : Intensive care unit survivors exhibited a high incidence of physical impairment and pain at six months, impacting HRQOL. Very few patients met full ICU-AW criteria. CLINICAL IMPLICATIONS : Physical impairment after critical illness is multifactorial and is not only attributable to muscle weakness. The recovery process of young, previously non-frail ICU survivors in the public healthcare setting may be improved by introducing rehabilitation pathways.
Predictors of return to work among mine workers following on-duty injury : a scoping review
(AOSIS, 2025-06-30) Botha, Wilinda; Magida, Nontembiso; Mudzi, Witness; Bello, Bashir
BACKGROUND : Mining industry workers face substantial challenges returning to work after occupational injuries. Despite the critical importance of successful return to work (RTW) outcomes, there is limited understanding of specific predictors within the mining sector that influence these outcomes. OBJECTIVES : To systematically identify and analyse factors influencing RTW among mine workers following on-duty injuries and synthesise evidence to inform rehabilitation strategies. METHOD : We searched PubMed, CINAHL, Google Scholar and PsycINFO databases for literature published between 1996 and December 2024. Studies were screened using predetermined inclusion and exclusion criteria. Data from eligible studies were extracted and analysed thematically to identify key predictors of RTW outcomes. RESULTS : Three studies met the inclusion criteria. Negative RTW predictors (barriers) included physical complications (muscular atrophy, chronic pain), psychological factors (work avoidance, secondary gains) and workplace challenges (harsh conditions, job stress). Positive predictors (facilitators) encompassed supportive work environments, shorter rehabilitation periods, and financial stability. Demographic characteristics, particularly younger age and higher education levels, were associated with improved RTW outcomes. CONCLUSION : Return to work success among mine workers is influenced by multiple interconnected factors spanning physical, psychological, workplace and demographic domains. CLINICAL IMPLICATIONS : These findings emphasise the need for comprehensive rehabilitation programmes integrating medical care, psychological support and workplace modifications. Future research should focus on developing targeted interventions that address these multiple dimensions of RTW in the mining sector.
Health systems and quality of life : the situation of South Africans with spinal cord injury
(AOSIS, 2025-06-06) Nizeyimana, Eugene; Rhoda, Anthea; Mothabeng, Joyce Diphale; Theron, Francois; Joseph, Conran
BACKGROUND : Spinal cord injury (SCI) significantly impacts quality of life (QoL) through physical disabilities and reduced social participation. OBJECTIVES : This study compared health system indicators, social factors and self-reported QoL between individuals with SCI accessing public versus private healthcare in South Africa. METHOD : A cross-sectional survey using the International Spinal Cord Injury (InSCI) community survey questionnaire was conducted with 200 SCI individuals (156 public, 44 private sector) from Cape Town and Pretoria. Chi-square tests and correlation analyses were performed. RESULTS : Significant disparities were observed between cohorts. Public sector participants reported higher rates of disability pension receipt (82.1% vs 54.5%) and greater challenges accessing various services. Overall, self-reported QoL was 56%, with the private cohort reporting significantly higher satisfaction (64% vs 52%). Private sector participants also reported higher satisfaction with living conditions and personal relationships. Access to disability pension and healthcare negatively correlated with QoL, while access to public spaces, medication, transport and nursing care positively correlated with QoL. CONCLUSION : This study reveals significant disparities in health system performance, social factors and QoL between SCI individuals accessing public versus private healthcare in South Africa. CLINICAL IMPLICATIONS : Findings highlight the need to address systemic inequities in healthcare access and social support for individuals with SCI to improve QoL across sectors.
Developing a knowledge sharing strategy for a South African IT consultancy
(AOSIS, 2025-06-07) Swanepoel, Daniëlle; Laughton, Paul; Meyer, Anika
BACKGROUND : Information technology (IT) consultants find themselves in a fast-paced, fast-changing environment where client satisfaction, project success and problem-solving are their greatest responsibilities. Because of the characteristics of this environment, there is a need in the IT consultancy industry for effective knowledge sharing, to assist their consultants to solve problems faster. OBJECTIVES : The focus of this study was therefore to create such a knowledge sharing strategy by investigating what would be included in a strategy, what the benefits of a knowledge sharing strategy is and what could hinder consultants from sharing their knowledge. METHOD : Qualitative data were collected through semi-structured interviews with the consultants from the IT consultancy, with the intention to investigate their current knowledge sharing habits and needs, while literature was also consulted to determine the current practices within similar industries. RESULTS : The outcome of the data and literature analysed lead to the development of a knowledge sharing strategy for the IT consultancy where the research was conducted. CONCLUSION : In summary, this study concludes with the development of a customised knowledge sharing strategy, with the intention to increase the IT consultants’ ability to deliver better products and enhance their problem-solving abilities. CONTRIBUTION : This study contributed to the limited existing research on knowledge sharing within South African IT consultancies, thereby enhancing the field of Information Science. It has also granted IT consultancies with insight into how consultants share knowledge and what these consultants believe could be improved regarding knowledge sharing.
The impact of climate-smart agriculture practices on household vulnerability to climate change : evidence from Zimbabwe
(Taylor and Francis, 2025) Okumu, Boscow; Ntuli, Herbert; Muchapondwa, Edwin; Mudiriza, Gibson; Mukong, Alfred
Climate change and variability pose a significant hindrance to agricultural productivity. The adverse effects are particularly concerning in many African countries that rely heavily on rainfed subsistence agriculture for their livelihoods. The promotion of climate-smart agriculture technologies as a pathway to enhancing food security, farmers' welfare, and providing climate adaptation and mitigation benefits is one of the several interventions aimed at improving agricultural productivity. However, there has been a dearth of evidence on the determinants of adoption of climate-smart agriculture practices as well as the impact of climate-smart agriculture practices on food security and household welfare. This paper contributes to this knowledge gap by using the probit model to explore the drivers of uptake of climate-smart agriculture practices, and the inverse probability weighting regression model and the instrumental variable approach to assess the impact on food security, household savings and household vulnerability. We find that the adoption of climate-smart agriculture practices among smallholder farmers is influenced by land ownership, climatic variables, land terrain and household sociodemographic characteristics. The study further revealed that adoption of climate-smart agriculture practices leads to a reduction in household savings and household vulnerability but leads to improved food security. Policy implications are also discussed.
Interactions among nutrients govern the global grassland biomass-precipitation relationship
(National Academy of Sciences, 2025-04-11) Fay, Philip A.; Gherardi, Laureano A.; Yahdjian, Laura; Adler, Peter B.; Bakker, Jonathan D.; Bharath, Siddharth; Borer, Elizabeth T.; Harpole, W. Stanley; Hersch-Green, Erika; Huxman, Travis E.; Macdougall, Andrew S.; Risch, Anita C.; Seabloom, Eric W.; Bagchi, Sumanta; Barrio, Isabel C.; Biederman, Lori; Buckley, Yvonne M.; Bugalho, Miguel N.; Caldeira, Maria C.; Catford, Jane A.; Chen, Qingqing; Cleland, Elsa E.; Collins, Scott L.; Daleo, Pedro; Dickman, Christopher R.; Donohue, Ian; Dupre, Mary E.; Eisenhauer, Nico; Eskelinen, Anu; Hagenah, Nicole; Hautier, Yann; Heckman, Robert W.; Jonsdottir, Ingibjoerg S.; Knops, Johannes M.H.; Laungani, Ramesh; Martina, Jason P.; Mcculley, Rebecca L.; Morgan, John W.; Venterink, Harry Olde; Peri, Pablo L.; Power, Sally A.; Raynaud, Xavier; Ren, Zhengwei; Roscher, Christiane; Smith, Melinda D.; Spohn, Marie; Stevens, Carly J.; Tedder, Michelle J.; Virtanen, Risto; Wardle, Glenda M.; Wheeler, George R.
Ecosystems are experiencing changing global patterns of mean annual precipitation (MAP) and enrichment with multiple nutrients that potentially colimit plant biomass production. In grasslands, mean aboveground plant biomass is closely related to MAP, but how this relationship changes after enrichment with multiple nutrients remains unclear. We hypothesized the global biomass–MAP relationship becomes steeper with an increasing number of added nutrients, with increases in steepness corresponding to the form of interaction among added nutrients and with increased mediation by changes in plant community diversity. We measured aboveground plant biomass production and species diversity in 71 grasslands on six continents representing the global span of grassland MAP, diversity, management, and soils. We fertilized all sites with nitrogen, phosphorus, and potassium with micronutrients in all combinations to identify which nutrients limited biomass at each site. As hypothesized, fertilizing with one, two, or three nutrients progressively steepened the global biomass–MAP relationship. The magnitude of the increase in steepness corresponded to whether sites were not limited by nitrogen or phosphorus, were limited by either one, or were colimited by both in additive, or synergistic forms. Unexpectedly, we found only weak evidence for mediation of biomass–MAP relationships by plant community diversity because relationships of species richness, evenness, and beta diversity to MAP and to biomass were weak or opposing. Site-level properties including baseline biomass production, soils, and management explained little variation in biomass–MAP relationships. These findings reveal multiple nutrient colimitation as a defining feature of the global grassland biomass–MAP relationship. SIGNIFICANCE Understanding how multiple interacting nutrients regulate the global relationship between mean annual precipitation and aboveground biomass is crucial for forecasting how ecosystem functioning will be altered by ongoing global changes. We fertilized with nitrogen, phosphorus, and potassium plus micronutrients in all combinations in 71 grasslands representing a global precipitation gradient. The grassland biomass–precipitation relationship became steeper with an increasing number of added nutrients. Increases in steepness corresponded to the form of interaction among added nitrogen and phosphorus. We found weak evidence that variation in plant species diversity mediated changes in the biomass–precipitation relationship. Multiple nutrient colimitation, particularly by nitrogen and phosphorus, is a defining feature of grassland biomass–precipitation relationships, and crucial to predicting grassland responses to global change.
The tails of gravity : using expectiles to quantify the trade-margins effects of economic integration agreements
(Elsevier, 2025-09) Bergstrand, Jeffrey H.; Clance, Matthew W.; Silva, J.M.C. Santos; matthew.clance@up.ac.za
Although there is evidence suggesting that the effects of trade liberalizations likely vary across the distribution of trade flows, trade economists have focused almost entirely on conditional mean estimates of their trade elasticities. We propose the novel use of Poisson-based expectile regressions to estimate the heterogeneous effects of trade liberalizations across the entire conditional distribution. Like standard Poisson regression, this method does not need the dependent variable to be logged, accommodates a mass of observations at zero, and is easy to implement, allowing the estimation of gravity equations with the standard three-way fixed effects specification. Using the proposed estimator, we find systematic evidence that trade liberalizations have larger effects at the lower tail of the conditional distribution. We then use the proposed method to investigate the causes of this heterogeneity, and our results suggest that the success of trade liberalizations strongly depends on potential for expansions along the extensive margin.
Relationships between biologically-informed reinforcement sensitivity and occupationally-focused high-potential personality traits
(Hogrefe, 2025) Furnham, Adrian; Corr, Philip J.; Semmelink, David Sanele
We compared two measurement models of personality: the biologically-informed Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ) and the occupationally-focused High Potential Trait Inventory (HPTI). The primary aim was to determine the extent to which the RST-PQ underpins the construct validity of the HPTI. This was achieved by examining the basic motivations of approach, avoidance, and conflict, thus pointing to possible mechanisms as to how HPTI traits may be related to occupational performance. Three hundred and thirty respondents (mean age: 46.5 years), the majority (78%) of whom were employed full-time, were sampled from different countries by a major test publisher. Several statistically significant and theoretically meaningful correlations were found between RST-PQ and HPTI factors (e.g., the positive association of HPTI Conscientiousness and RST-PQ BAS-Goal-drive Persistence). Some sex and age differences were found in both sets of factors. Following zero-order correlational analysis, regression analyses helped further clarify these RST-PQ/HPTI associations. These findings throw empirical light on the relationships of two distinct personality measurement models, with very different origins – specifically, the biological inspiration of the RST-PQ contributes new knowledge as to the construct nature of the HPTI, pointing to viable hypotheses as to how HPTI factors should relate to occupationally-relevant data (e.g., sales performance). In general, the two models may be seen as complementary, each adding unique insights into personality. A study showing how these different factors relate to external criteria is now needed to speak to their respective predictive validities.

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