Research Articles (University of Pretoria)

Permanent URI for this collectionhttp://hdl.handle.net/2263/121

This collection offers open access to the full text of research articles published by staff, students and affiliates of the University of Pretoria. These items are identical in content to their published counterparts. It is linked to the Research Information System and complements the Annual Research Report.

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The pursuit of decent work in precarious contexts : motorbike delivery riders' psychological experiences
Baldry, Kim; Koekemoer, Eileen; Olckers, Chantal (Sage, 2026)
Digital platforms have reshaped labour markets worldwide, increasing gig work opportunities, particularly for motorbike delivery riders in South Africa, a country grappling with high unemployment. However, these self-employed workers often face a lack of job security, benefits, and protections due to informality, weak labour laws, and deep socioeconomic inequality, highlighting the contrast with the International Labour Organisation’s decent work principles. This research explores the work experiences of platform-based motorbike delivery riders in South Africa, aiming to improve our understanding of platform-based work and decent work experiences in the gig economy. Within a constructivist paradigm, this study adopted a qualitative descriptive design to investigate the experiences of motorbike delivery riders in Gauteng, South Africa, with ten participants each undergoing two interviews. The data were analysed through hybrid thematic analysis. Findings reveal that precarious gig conditions and structural inequalities influence rider’s experiences of decent work, which can be categorised into three interconnected decent work themes: (1) safety and healthcare, (2) income security, and (3) work–life balance. This research underscores the need for context-sensitive applications of the psychology of working theory, acknowledging the complex interplay of economic constraints, access to decent work, and the fulfilment of psychological needs in the gig economy.
The regulatory, normative and cultural-cognitive dimensions of the returnee opportunity and returnee liability : how institutional migration creates the two sides of the same coin
Mreji, Pamela Adhiambo; Chrysostome, Elie Virgile; Barnard, Helena (Elsevier, 2026-08)
Why do some scholars emphasize the benefits realized by returnee entrepreneurs, whereas others highlight the returnee liability? By analyzing interviews with twenty Kenyan returnee entrepreneurs, we make three contributions to scholarship on returnee entrepreneurship. First, we reconcile two well-developed but separate and almost-contradictory bodies of the extant literature by showing that the returnee opportunity / returnee liability is a duality that all returnee entrepreneurs can expect and must manage, even if their ventures are successful. Returnees might see opportunities in the institutional differences between their home and host countries, but to realize those opportunities as entrepreneurial ventures, they must navigate their homeland’s de-familiarized regulatory, normative and cultural-cognitive macro-level institutional pillars. We show how returnee entrepreneurs navigate these macro-institutions as individuals, leading to our second contribution: Where people are mobile across borders, macro-institutions affect not only organizational processes, but also individuals directly. The theory of individual institutional migration suggests institutional migrants seek to regain personal control vis-à-vis a new institutional domain either by transposing knowledge from the previous institutional environment, or by internalizing the new institutional rules. Our third contribution is to advance that theory by suggesting that returnee entrepreneurs strategically seek to do both: Where they recognize opportunities in the new institutional environment (i.e. returnee opportunity), they transpose knowledge by starting innovative new ventures, but at the same time, the different macro-institutional environment imposes a burden (i.e. returnee liability) that they need to manage to gain acceptance of their ventures. HIGHLIGHTS • Returnee entrepreneurs are institutional migrants. • They carry the rules from one institutional environment to another. • They navigate macro institutions as individuals. • This results in a duality – both returnee opportunities and a returnee liability. • The duality functions across regulatory, normative and cultural-cognitive pillars.
Extracts of selected South African medicinal plants mitigate virulence factors in multidrug-resistant strains of Klebsiella pneumoniae
Adeosun, Idowu Jesulayomi; Baloyi, Itumeleng Tsebang; Cosa, Sekelwa (Wiley, 2023-10)
The emergence of multidrug-resistant (MDR) Klebsiella pneumoniae remains a global health threat due to its alarming rates of becoming resistant to antibiotics. Therefore, identifying plant-based treatment options to target this pathogen’s virulence factors is a priority. This study examined the antivirulence activities of twelve plant extracts obtained from three South African medicinal plants (Lippia javanica, Carpobrotus dimidiatus, and Helichrysum populifolium) against carbapenem-resistant (CBR) and extended-spectrum beta-lactamase (ESBL) positive K. pneumoniae strains. The plant extracts (ethyl acetate, dichloromethane, methanol, and water) were validated for their inhibitory activities against bacterial growth and virulence factors such as biofilm formation, exopolysaccharide (EPS) production, curli expression, and hypermucoviscosity. The potent extract on K. pneumoniae biofilm was observed with a scanning electron microscope (SEM), while exopolysaccharide topography and surface parameters were observed using atomic force microscopy (AFM). Chemical profiling of the potent extract in vitro was analysed using liquid chromatography-mass spectrometry (LC-MS). Results revealed a noteworthy minimum inhibitory concentration (MIC) value for the C. dimidiatus dichloromethane extract at 0.78 mg/mL on CBR- K. pneumoniae. L. javanica (ethyl acetate) showed the highest cell attachment inhibition (67.25%) for CBR- K. pneumoniae. SEM correlated the in-vitro findings, evidenced by a significant alteration of the biofilm architecture. The highest EPS reduction of 34.18% was also noted for L. javanica (ethyl acetate) and correlated by noticeable changes observed using AFM. L. javanica (ethyl acetate) further reduced hypermucoviscosity to the least length mucoid string (1 mm-2 mm) at 1.00 mg/mL on both strains. C. dimidiatus (aqueous) showed biofilm inhibition of 45.91% for the ESBL-positive K. pneumoniae and inhibited curli expression at 0.50 mg/mL in both K. pneumoniae strains as observed for H. populifolium (aqueous) extract. Chemical profiling of L. javanica (ethyl acetate), C. dimidiatus (aqueous), and H. populifolium (aqueous) identified diterpene (10.29%), hydroxy-dimethoxyflavone (10.24%), and 4,5-dicaffeoylquinic acid (13.41%), respectively, as dominant compounds. Overall, the ethyl acetate extract of L. javanica revealed potent antivirulence properties against the studied MDR K. pneumoniae strains. Hence, it is a promising medicinal plant that can be investigated further to develop alternative therapy for managing K. pneumoniae-associated infections.
The disposal of placenta among indigenous groups globally : an integrative literature review
Moeti, Cecilia; Mulaudzi, Fhumulani Mavis; Rasweswe, Molatelo Melitah (Wiley, 2023-10)
INTRODUCTION : The placenta, or afterbirth, plays a vital role in supplying nutrients and oxygen via the umbilical cord. Western medicine sees the placenta as a medical waste and discards it after delivery. Meanwhile, indigenous groups observe rituals or ceremonies prior to their disposal since it bears sacred importance. AIM : The aim of the literature review is to review the current literature on indigenous methods of disposing placenta. METHODS : Through the EBSCOhost search engine, the authors had access to the following databases: CINAHL; MEDLINE; E-Journals; Health Sources: Nursing/Academic Edition; Scopus; and African Journals Online. A manual search of the grey literature through Google Scholar and Google Search engines, as well as citation searching using reference lists, was also used. The following keyword searches came up: placental disposal, placental waste, placental release, indigenous placental disposal, traditional placental disposal, cultural placenta, and placental rituals. The authors followed the inclusion criteria of qualitative, quantitative, or mixed research articles or reports from experts and different organisations published between 2013 and 2022 in English. FINDINGS : The following three themes with subthemes emerged in the context of this review paper: (1) placental consumption (increases milk production, prevents postpartum depression, and prevents postpartum bleeding); (2) placental burial (burial site determines the child’s fate, protection of the child, and fertility); and 3). artifacts (memorabilia). CONCLUSION : Indigenous placental disposal methods have a significant value to Indigenous women globally. The rituals performed have a special meaning attached to them. It is important for Western medicine to respect and support indigenous placental disposal methods and ensure safe handling from the healthcare facilities to their homes.
Variations of labour aristocracy and union trajectories across South Asia
Shakya, Mallika (Springer, 2023-06)
This book is a consolidation of Jonathan Parry’s longstanding argument about the importance of looking at variations of lived experience among blue-collar workers. His ethnographic engagement with industrial labour in the postcolonial steel town of Bhilai in central India humanizes class alongside caste and culture while urging readers to consider eclecticism as the lens through which to study working class lives. Parry’s Bhilai ethnography is enriched by the comparisons he draws with sister undertakings in Orissa and West Bengal, using which he proposes that a diverse range of social life is inextricably interwoven within the so-called working class, thereby generating a distinct cycle of social coercion and political exploitation that goes beyond the bifurcation of class.
Application of cement-cassava peel ash mix for the stabilisation of marine clay soil : a review
Oruabena, Bernard; Steyn, Wynand Jacobus Van der Merwe (Springer, 2026)
This review investigated the application of cement and Cassava Peel Ash (CPA) for stabilising Marine Clay Soil (MCS). This material exhibits unusually high plasticity and compressibility and low shear strength, creating challenging conditions for stabilisation. In recent decades, lime and cement have been utilised to enhance the resilience of MCSs. However, the environmental and economic sustainability of this practice has come into question due to the substantial carbon dioxide emissions produced during cement manufacturing. Cement-free stabilisation using the scientifically innovative agricultural by-product CPA has been developed as an eco-friendly and cost-effective alternative, leveraging its improved pozzolanic activity to enhance the structural characteristics of MCS, such as strength, stiffness, and permeability. Although the combination of cement and CPA could significantly benefit the structural engineering of MCS, understanding the detailed mechanisms of cement-free stabilisation remains complex, limiting its widespread application. This review indicates that the CPA-cement mix can enhance key aspects of MCS, including permeability, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS).
Application of a hierarchical solution scheme to the analysis and design of large-scale tabular mine layouts
Napier, J.A.L. (John); Malan, D.F. (Daniel Francois); Jooste, Yolande (Springer, 2026-02)
This paper outlines a hierarchical computational strategy for solving large-scale tabular deposits using the displacement discontinuity boundary element method. This scheme facilitates the detailed analysis of local regions of interest, where current mining activity is in progress. The suggested approach requires an overall solution of the mine layout with a coarse element mesh to be obtained, which is then used to generate the background stress field for fine-scale solutions in selected regions of interest. The fine mesh solutions are established using the appropriate induced external coarse solution stress influence calculated in the selected region of interest using high order elements. The fine-scale solutions may involve detailed excavation extensions or time-dependent crushing of the fracture zone adjacent to the mined excavation edges. This analysis may require periodic re-calculation of the coarse scale background influence. An additional influence matrix partitioning scheme is also proposed as a strategy to incorporate automatically the effect of the induced background stress influence. A case study simulating the time-dependent convergence of a mining panel in a large-scale shaft pillar geometry is used to illustrate these hierarchical solution schemes. HIGHLIGHTS • This paper illustrates a hierarchical computational strategy for solving large-scale tabular layouts using the displacement discontinuity boundary element method. Particular attention is given to addressing the accuracy of the scale transition between coarse and fine mesh calculations using high order elements. • The beneficial use of influence matrix partitioning in local regions of interest allows an efficient analysis of the time-dependent evolution of the fracture zone for stability modelling and the assessment of adverse ground conditions, where current mining activity is in progress. • A simulation of the time-dependent convergence of a mining panel in a large-scale shaft pillar geometry is presented to illustrate the application of the proposed procedure. • Time-dependent convergence profiles similar to those recorded in underground panels can be simulated.
Antiretroviral therapy status and factors associated with ART use among orphaned and vulnerable children (OVC) living with HIV in Namibia
Moyo, Enos; Mangwana, Hadrian; Melese, Endalkachew; Takawira, Simon; Harases, Bernadette; Indongo, Rosalia; Moyo, Perseverance; Nyoni, Ntombizodwa Makurira; Dzinamarira, Tafadzwa (Taylor and Francis, 2026)
This study assessed the antiretroviral therapy (ART) status and factors associated with ART use among Children and adolescents living with HIV (C/ALHIV) enrolled in the Namibia OVC program. This retrospective cross-sectional secondary analysis study used data collected at enrolment of C/ALHIV participating in the OVC program, implemented by Project HOPE Namibia (PHN) from 1 August 2023. Data were analyzed utilizing IBM Statistical Package for Social Sciences (SPSS) version 29. Among the 4599 participants included in this analysis, 4441 (96.6%) participants were on ART, with a 95% confidence interval (CI) (96.1% − 97.1%). Participants more likely to be on ART were from households with little or no hunger (Crude Odds Ratio (COR) = 2.19, 95% CI (1.40 – 3.43)), from Eenhana (adjusted odds ratio (AOR) = 8.24, 95% CI (2.58 – 26.37)), Engela (AOR = 3.72, 95% CI (1.63 – 8.50)), Okongo (AOR = 5.22, 95% CI (1.22 – 22.38)), Oshakati (AOR = 2.50, 95% CI (1.04 – 6.01)), and Oshikuku (AOR = 3.70, 95% CI (1.18 – 11.55)). In contrast, participants who were less likely to be on ART were aged 0–9 years, never enrolled at a school (COR = 0.26, 95% CI (0.18 – 0.37)), and were diagnosed or presumed to be with TB (AOR = 0.10, 95% CI (0.01 – 0.73)). Additionally, participants from child-headed households, those who were sexually abused or sexually exploited, were less likely to be on ART, COR = 0.02, 95% CI (0.01 – 0.03), COR = 0.04, 95% CI (0.02 – 0.06), and COR = 0.12, 95% CI (0.10 – 0.15), respectively. The findings indicate that integrating food support into HIV programs may enhance ART uptake among C/ALHIV. Strategies should be implemented to improve the enrolment for OVC in educational institutions.
Antimicrobial use and manure management practices among commercial chicken farmers in selected regions of Tanzania : gaps and strategies for mitigating antimicrobial resistance
Biginagwa, Fares J.; Mzula, Alexanda; Westwood, Erica; Ochai, Sunday Ochonu; Nonga, Hezron E.; Dalsgaard, Anders; Mdegela, Robinson H. (MDPI, 2026-02)
The intensification of commercial chicken production has increased antimicrobial use and manure generation, raising concerns about residues and resistant pathogens entering the environment. Use of raw chicken manure can introduce antimicrobial compounds and resistance determinants into agricultural soils. This study examined antimicrobial use and manure management practices among chicken farmers in Morogoro, Dar es Salaam, and Unguja, and identified key gaps in national regulatory frameworks and their on-farm implementation. A structured questionnaire was administered to 351 farmers to assess the types and usage of antimicrobials and manure handling practices. Farmers reported using fourteen antibiotic classes and four antiparasitic agents, with tetracycline being the most frequently used (54.1%). Most farmers in Unguja (97.7%), Dar es Salaam (87.3%), and Morogoro (70.9%) either apply manure as fertilizer, sell it, or both. A large proportion (93.2%) reported that they do not process manure before use or sale, mainly due to lack of technical knowledge (77.4%). Awareness of the health hazards posed by pathogens (43.3%) and drug residues (57.5%) is low. This study revealed critical gaps, including weak regulatory enforcement, inadequate surveillance systems, limited cross-sectoral integration, irrational antimicrobial use, and limited farmer awareness. Strengthening regulatory frameworks, improving farmer training, and promoting safer manure management methods are recommended to reduce the environmental dissemination of antimicrobial residues and resistance. HIGHLIGHTS Public health relevance—How does this work relate to a public health issue? • Antimicrobial resistance (AMR) is a major global public health threat that compromises the treatment of infectious diseases. • Environmental exposure to antimicrobial residues and resistant bacteria through agricultural use of poultry manure represents an under-recognized pathway for AMR transmission. Public health significance—Why is this work of significance to public health? • Awareness may help to improve practices aiming to mitigate the spread of antimicrobial resistance, lowering the risk of hard-to-treat infections to humans and animals. • This paper provides recommendations for strategic interventions focusing on improving manure handling and antimicrobial use practices to reduce environmental contamination, thereby safeguarding community health. Public health implications—What are the key implications or messages for practitioners, policymakers and/or researchers in public health? • Promoting validated manure treatment methods such as composting could substantially reduce environmental AMR risks while supporting safe organic fertilizer use. • The findings highlight the need to integrate manure management into national AMR-frameworks and to enforce regulations requiring treatment of poultry manure before agricultural use.
Apple hearing test feature for the AirPods Pro 2 : accuracy, reliability, and time-efficiency
Kruger, Megan; Manchaiah, Vinaya; Swanepoel, De Wet (Wiley, 2026-03)
OBJECTIVE : To evaluate the accuracy, test-retest reliability, and time-efficiency of Apple's Hearing Test Feature (HTF) compared to reference standard pure-tone audiometry (PTA). STUDY DESIGN : Cross-sectional validation study. SETTING : Single-center study at a university clinic. PTA was performed in a sound-treated booth. HTF testing occurred in a quiet room. METHODS : A sample of 25 adults (mean age 50.1 years [SD 14.2]; 68% female) with self-reported mild-to-moderate hearing loss participated. Each contributed 16 thresholds, yielding 400 comparisons. Participants underwent PTA by an audiologist, followed by two independent HTF assessments (start and end of session) using Apple AirPods Pro 2 paired with an iPhone 13. Outcomes included threshold accuracy versus PTA, test-retest reliability, and test duration. RESULTS : Across 400 comparisons, 86.5% of HTF thresholds were within 10 dB HL of PTA. Root mean square deviation (RMSD) values ranged from 3.3 to 7.9 dB HL (left ear) and 5.8 to 9.7 dB HL (right ear), meeting minimally acceptable accuracy (≤10 dB HL). Test-retest was reliable, 84.1% of thresholds within 5 dB HL and 96.6% within 10 dB HL. Desired reliability (≤6 dB HL) was met at all frequencies except 250 Hz (left ear), which met minimum acceptable level. HTF was significantly faster (median 5.5 minutes) than PTA (10.0 minutes; P < .001). CONCLUSION : Apple's HTF demonstrated clinically acceptable accuracy and reliability, with improved time-efficiency compared to PTA. Findings support its potential for consumer-led hearing monitoring and OTC hearing aid self-fitting. Further research should assess inter-device reliability and integration with Apple's Hearing Aid Feature.
Antigenic and genotypic relatedness of buffalo-derived Theileria parva from Zambia to cattle-derived parasites and vaccine stocks
Choopa, Chimvwele Namantala; Muleya, Walter; Mukolwe, Lubembe Donald; Fandamu, Paul; Sibeko-Matjila, Kgomotso Penelope (Elsevier, 2026-04)
The African buffalo (Syncerus caffer) is the natural reservoir of Theileria parva, a tick-transmitted protozoan parasite that severely constrains cattle production across eastern, southern, and central Africa. While the antigenic and genetic diversity of cattle-derived T. parva (causing East Coast fever) is well characterized in Zambia, little is known about the buffalo-derived parasites. The latter cause the equally fatal Corridor disease and impact the epidemiology and control of bovine theileriosis, particularly where live vaccines are used. This study investigated antigenic and genotypic diversity of T. parva from three Zambian buffalo populations, in comparison with cattle-derived parasites and vaccine stocks (Katete and Chitongo). Analysis of Tp1 and Tp2 antigen genes revealed contrasting diversity. Tp1 epitopes showed limited variation, whereas Tp2 exhibited extensive polymorphism, especially among buffalo-derived sequences. None of the variations have been previously reported in Zambia, suggesting ongoing diversification. Phylogenetic analysis showed paraphyletic clustering of buffalo and cattle parasites. However, some buffalo genotypes grouped closely with vaccine strains, suggesting potential cross-protection. Only two Tp2 sequences from buffalo-derived parasites clustered with those from cattle or vaccines, highlighting a risk of vaccine break-through. Population genetic analysis using multilocus genotyping demonstrated higher allelic richness and diversity in buffalo-derived parasites compared to cattle-derived. Although buffalo parasites showed greater multiplicity of infection (MOI) and unique alleles, principal coordinate analysis revealed limited genetic sub-structuring and shared alleles across hosts. These results suggest a common ancestry and overlapping transmission cycles. The greater MOI in buffalo populations highlights higher genetic exchange and can complicate control efforts. Overall, the study demonstrates extensive antigenic and genetic diversity of buffalo-derived T. parva in Zambia. These findings have critical implications for current vaccine efficacy, emphasizing the need for continuous molecular surveillance, strict livestock movement control, and vaccine efficacy trials to ensure effective management of T. parva infections. HIGHLIGHTS • Buffalo are a major reservoir of Theileria parva antigenic and genetic diversity. • Some Zambian buffalo-derived T. parva strains are related to ECF strains. • Buffalo-derived T. parva genotypes shown a distant relationship to vaccine stocks. • Current vaccines may offer limited protection against buffalo-derived T. parva.
Anti-COVID-19 vaccine narratives among African and North American Neo-Pentecostals (Part 1) : evidence, causes and lessons
Orogun, Daniel (Springer, 2026-01)
The gap in the worldview of spiritual leaders regarding public health and safety became apparent during the COVID-19 pandemic. It engendered narratives and health behaviors that led to the deaths of many. This interdisciplinary study examines the relationship between religious beliefs, practices, and health behavior. In two parts, this empirical research, through a literature review, secondary data analysis, and available narratives in academic and media spaces, deconstructs the activities of some African and North American Neo-Pentecostals during the pandemic. Part 1, presented here, provides evidence of the narratives and discusses the causes of misinformation and hesitancy. Part 2 addressed the public health implications, the ideal theological response, leadership gaps, and lessons learned. Three fundamental points are evident in both parts. The first is a poor “theology of medicine” in health crises. The second is the poor leadership approach to crisis management. The third is the long-term tension and a lack of synergy between health professionals, health policymakers, and spiritual leaders. The outcome of Part 1 revealed that the causes of anti-vaccination narratives are rooted in theological, social, and economic factors. Part 1 concludes with a summary of the lessons and an overview of what to expect in Part 2 of the exercise.
Application of machine learning in predicting corrosion inhibition capacity of Spinacia oleracea leaf extract on copper
Sanni, Omotayo; Adeleke, Oluwatobi; Iwarere, Samuel Ayodele; Jen, Tien-Chen; Daramola, Michael Olawale (Elsevier, 2026-01)
In many different industries, material corrosion is a major problem and it has a big financial impact. In this case, plant extracts employed as corrosion inhibitors, provide affordable way to prevent copper from corroding in acidic media, providing an alternative to the dangerous chemicals now in use. This study presents an integrated experimental and machine learning approach for investigating the corrosion inhibition performance of Spinacia oleracea leaf extract on copper in nitric acid medium. Experimental procedure involving gravimetric analysis under different concentrations, temperatures, and exposure durations, inhibitory efficiency was conducted. Different machine learning (ML) models, namely Artificial Neural Network (ANN), Random Forest (RF), Support Vector Machine (SVM), and Decision Tree (tree) were developed for predicting the corrosion rate. To overcome the black-box limitation of the ML models, an interpretable feature analysis was carried using Shapley Additive ExPlanations (SHAP).The accuracy and validity of the models were evaluated using statistical tests like Root Mean Square Error (RMSE), Mean Absolute Error (MAE), Mean Absolute Deviation (MAD), Mean Absolute Percentage Error (MAPE), and Variance Accounted For (VAF).The best prediction accuracy was obtained with SVM, giving an averaged validation-based RMSE, MAE, MAD, MAPE, and VAF values of 0.386, 0.287, 0.192,0.08773, and 99.093, respectively, across 5 folds. SHAP interpretability identified inhibitor concentration as the most influential variable controlling corrosion inhibition. The data-driven framework that combines experimental gravimetric analysis with SHAP-enhanced ML in this study contributes to the broader development of transparent, eco-friendly, and data-driven corrosion prediction models.
Anticipatory edge intelligence : a foundational enabler for resilient critical infrastructure systems
Lall, Shruti; Pillay, Nelishia (Institute of Electrical and Electronics Engineers, 2026-01)
Critical infrastructure systems (CISs), such as power grids, water networks, and transportation systems, operate under stringent requirements for timeliness, resilience, and coordinated response. As these systems become increasingly data-driven and automated, decisions must often be made under uncertainty and with limited tolerance for delay. This position article advocates for anticipatory edge intelligence (AEI) as a conceptual framing for designing edge-enabled intelligence in CISs, with resilience and containment as primary objectives. AEI emphasizes the generation, exchange, and operationalization of short-horizon anticipatory information at the edge to enable coordinated, preemptive action before degradation propagates. The article examines key challenges faced by CISs, identifies opportunities where anticipatory coordination can enhance system-level resilience, and uses an illustrative scenario to motivate this perspective. By articulating AEI as a research and design lens, this work aims to guide future investigation into resilient, edge-enabled infrastructure systems.
Unveiling the role of aeration systems in the bioaerosol emission rate, particle size and microbial composition from wastewater treatment plants
Kumalo, Puseletso C.; Amoah, Isaac D.; Pierneef, Rian Ewald; Ismail, Arshad; Bux, Faizal; Kumari, Sheena (Elsevier, 2025-12)
Wastewater treatment plants (WWTPs) are important sources of bioaerosols; however, the influence of aeration on emission characteristics, particle size distribution, and microbial composition remains poorly studied. This study investigates how surface aeration (SA) and diffused aeration (DA) systems affect bioaerosol emission rates, particle size distribution, and microbial diversity using an 8-stage Andersen cascade impactor and shotgun metagenomics. Bioaerosol emission rates were estimated by combining measured particle concentrations with system-specific airflow rates. Abiotic factors were analysed through redundancy analysis to determine their influence on community structure. SA consistently generated higher emission rates, particularly in respirable particles (0.43–2.1 µm), which are capable of deep respiratory deposition. Dominant taxa included Rhodococcus, Pseudomonas, Bacillus, Meyerozyma, and Siphoviridae, with SA showing higher relative abundance of opportunistic pathogens even in smaller particle sizes. In contrast, DA systems exhibited a lower emission rate but broader microbial diversity, reflecting more stable aeration conditions. The study indicated that activated sludge was the main source of microbial populations, with a larger bioaerosol –activated sludge overlap in SA than DA. Redundancy analysis revealed that wind speed (WS) and relative humidity (RH) significantly influenced bacterial and viral populations, while WS and air temperature (AT) affected eukaryotes. Notably, SA emissions decreased with distance (100 m), while DA emissions increased. By quantifying emission rates rather than concentrations and integrating high-throughput metagenomics, this study provides a comprehensive framework for characterising bioaerosol hazards in WWTPs. These findings highlight the need for mitigation strategies in WWTPs, especially near SA systems.
Immunohistochemical investigation of canine lymph nodes collected during a rabies outbreak in South Africa
Rahmat, Redwan; Ravensberg, Matthijs F.; Schipper, Debby; Kroh, Keshia; Veldhuis Kroeze, Edwin J.B.; Kuiken, Thijs; Sabeta, Claude Taurai; GeurtsvanKessel, Corine H.; Embregts, Carmen W.E. (Microbiology Society, 2025-11-06)
Rabies is a fatal zoonosis that impairs host immune function, yet effects on peripheral lymphoid architecture are poorly defined. During a 2021–2022 rabies virus (RABV) outbreak in South Africa, we collected cervical lymph nodes from 36 rabies-suspect dogs; RABV RNA was detected in 27. Canine distemper virus RNA was detected in a subset across both RABV-positive (RABV+) and RABV-negative (RABV−) groups and was not associated with clinical-sign count. We set up a computer-assisted histological analysis tool to quantify germinal-centre (GC) nucleus density and immunohistochemistry for CD20, PNA and IBA1 to profile B cells, GC activity and macrophages. Within the outbreak cohort, GC density and marker-based metrics did not differ between RABV+ and RABV− dogs. Two healthy dogs were included as reference tissues; values in outbreak dogs were generally lower, but these contrasts are contextual given the limited, non-matched controls. This study provides a reproducible framework for quantifying immune cell organization in field-collected tissues during natural RABV exposure and highlights the need for larger, geographically matched control groups and complementary functional immune measurements.
Patterns of observer error in scoring macromorphoscopic traits for population affinity
Liebenberg, Leandi; Stull, Kyra Elizabeth; L'Abbe, Ericka Noelle (Wiley, 2025-07)
Revising methodologies is essential to understand the limitations and biases inherent in certain methods, which is crucial for obtaining reliable results. Due to the subjective nature of non‐metric methods, variation in trait scoring and its impact on accurately classifying biological parameters remains a concern that requires further investigation. This study aimed to examine the effects of observer experience, familiarity with the method, and different statistical approaches on the repeatability of macromorphoscopic traits in the cranium for population affinity. Seventeen traits were scored on a sample of 10 crania by five observers with varying experience levels. Intra‐observer agreement ranged from moderate to perfect, with three traits—inferior nasal margin, nasal bone shape, and nasal overgrowth demonstrating—the lowest agreement. Overall, inter‐observer repeatability ranged from poor to substantial agreement. After a group discussion on the scoring procedure and subsequent rescoring of the crania, a slight improvement in agreement was observed, with kappa values shifting towards moderate and substantial levels. Each observer exhibited variation in the repeatability of different traits. While general experience did not consistently translate into proficiency with the method, familiarity with the specific traits and scoring procedures contributed to more consistent results. Therefore, method‐specific training is crucial before applying the MMS traits in practice. Additionally, the choice of statistical approaches—such as applying different weights to Cohen's kappa based on data type—can influence the perceived reliability of a method. Practitioners should select weights and tests that are most appropriate for the data type of each trait being analyzed.
Network development mechanisms of immigrant entrepreneurs: insights from an emerging economy
Fubah, Clavis Nwehfor; Moos, Menisha (Emerald Publishing Limited, 2025-12)
PURPOSE ; This study aims to explore immigrant entrepreneurs’ (IEs) networks, particularly emphasising how these networks are developed in a host country when operating businesses. DESIGN/METHODOLOGY/APPROACH : A qualitative methodology was used, and data were collected from 25 IEs using semi-structured interviews via the purposive sampling method. FINDINGS : The findings indicated that IEs in South Africa (SA) develop their networks using various relationship-based and performance-based mechanisms. This study argued that trust is not (only) a relationship-based mechanism used in establishing networks but a fundamental ingredient for all successful networking mechanisms. ORIGINALITY/VALUE : This original paper contributed to immigrant entrepreneurship literature by providing unique insights into the network development mechanisms IEs use in SA. This aspect has not been sufficiently studied in emerging economies.
The tax evasion punishment system in South Africa
Viljoen, Janél; Du Preez, Hanneke (Elsevier, 2025-06)
Schemes to outsmart the revenue authority and circumvent the burden of paying taxes have been around since the early ages. Governments implement systems to combat and curb tax evasion, expecting that their punishment methods will deter people from evading tax; nevertheless, tax evasion remains a big concern. To develop effective and appropriate punishment methods to deter tax evasion, taxpayers and their perceptions of tax evasion should be considered. This article explores the tax evasion punishment methods in South Africa, with the aim of answering the research question: to what extent do the tax evasion punishment methods in South Africa deter tax evasion? A mixed-method research design was selected for this study. It includes data collection via questionnaires given to taxpayers and registered tax practitioners in South Africa and interviews with six expert role players in South Africa’s tax evasion punishment system. The participants’ perceptions of the appropriateness of the current tax evasion punishment methods in South Africa were explored along with taxpayers’ tax evasion behaviour.
Surrounded by wolves : a reparative visual criticism of Susanna (LXX Daniel 13) in text and early Christian art
Oberholzer, Ninnaku (Routledge, 2025-12-10)
This article is located at the intersection of text and image and proposes a reparative visual criticism (RVC) of the story of Susanna and the Elders found in Daniel 13 (LXX). As one of the earliest narratives depicted in early Christian art, the story of Susanna and the Elders forms part of a system of sepulchral iconographical themes which reassured early Christians suffering persecution with a promise of spiritual deliverance. Yet such visual exegesis only addresses the theological understanding of the text. This article explores the multilayered interpretations of Susanna through a variety of visual interpretations of the narrative in catacomb art and reflects on the text in the contemporary South African context, focusing on Susanna’s sexuality, shame, silence, and violence perpetrated against her. This approach is threefold. First, didactic visual interpretations of the narrative will be explored as representing the internal struggles of the early church regarding married female sexuality. Second, the allegorical representation of Susanna as a lamb will be investigated by engaging in contemporary feminist criticism regarding Susanna’s silence and shame in the text. Third, a South African contemporary discussion explores how the allegorical representation of Susanna as a lamb enters into a discussion with Judith Mason’s artwork The Blue Dress. The RVC method allows for a thorough exploration of the gender-based violence Susanna experiences and highlights the relevance of the narrative for past, present, and future readers/audiences.

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