Postprints (Articles)

Permanent URI for this collectionhttp://hdl.handle.net/2263/51908

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Abundance, diversity and development of thrips (Thysanoptera) on avocados and macadamias in the Levubu region of Limpopo Province, South Africa
(Wiley, 2025-08) Kibor, Maxwell K.; Sole, Catherine L.; Joubert, Elsje; Weldon, Christopher William; cwweldon@zoology.up.ac.za
Some thrips (Thysanoptera) species are presumed to injure avocado and macadamia trees and fruit when feeding as nymphs and adults. We investigated the abundance and species richness of thrips and monitored fruit and nut set and damage on four avocado (Fuerte, Hass, Maluma and Pinkerton) and macadamia (695, 814, 816 and A4) cultivars. Different stages of avocado fruit (1–3, 4–6 and 7–9 cm) or macadamia nut development (closed racemes, nut set, nut size 1–1.5 cm and nut size 3–4 cm) were sampled over two seasons in the Levubu region of Limpopo Province, South Africa. Thrips development on fruit, nuts and leaf flush was recorded to verify the thrips species causing damage. A total of 15 535 thrips were collected during August–January 2020–2021 and 2021–2022. Six thrips morphotypes were identified across macadamia and avocado orchards: Scirtothrips aurantii Faure (Thripidae), Thrips tenellus Trybom (Thripidae), Haplothrips gowdeyi Franklin (Phlaeothripidae), Frankliniella occidentalis Pergande (Thripidae), Megalurothrips sp. (Thripidae) and Caliothrips sp. (Thripidae). Thrips were less abundant in the 2020/2021 season compared to the 2021/2022 season and in avocados than in macadamias. Pinkerton (2020/2021: 4.9 ± 0.8 and 2021/2022: 13.1 ± 0.2) and Fuerte (2020/2021: 6.9 ± 1.3 and 2021/2022: 7.5 ± 0.1) had the highest damage and fruit set per inflorescence in both seasons. Fruit size 1–3 cm had a mean damage of 3.4 ± 0.8 in 2020/2021 and 4.0 ± 0.7 in 2021/2022, 4–6 cm had 5.3 ± 0.9 and 4.7 ± 0.7 in 2021/2022, and 7–9 cm had 5.2 ± 0.9 in 2020/2021 and 5.0 ± 0.8 in 2021/2022. Macadamia cultivars and developmental stages most affected by thrips were dependent on the season. Our results suggest that damage occurs earlier in fruit or nut development, and Fuerte avocados and Macadamia 695 were the least susceptible to thrips damage. S. aurantii larvae developed from all sampled avocado and macadamia tissues and were able to persist until the adult stage, confirming it as the main damaging thrips species of avocado and macadamia in the Levubu region.
Enhancing the energy yield of Amaranthus hybridus-derived biofuel using alkaline pretreatment : experimental and data-driven investigation
(Elsevier, 2026-02) Adeleke, Oluwatobi; Bamisaye, Abayomi; Ige, Ayodeji Rapheal; Adegoke, Kayode Adesina; Jen, Tien-Chien
he global quest for sustainable and eco-friendly fuel alternatives has spurred interest in biofuels. This study presents an experimental and data-driven framework for investigating the impact of alkaline-pretreatment on the combustion properties of solid-biofuel derived from Amaranthus hybridus. The aim of the study is to enhance the energy content of the biofuel using NaOH-pretreatment and provide data-driven insight into its energy drivers. The experimental analysis involved ultimate and proximate analysis, calorific value (CV) determination, and structural characterization. Advanced data analytics, including correlation analysis, feature importance analysis (FIA), dimensionality reduction using Principal Component Analysis (PCA), and neuro-fuzzy modelling, were developed to explore relationships among biofuel properties. A Grid Partitioning (GP)-clustered Adaptive Neuro-Fuzzy Inference System (ANFIS) tuned with Particle Swarm Optimization (PSO) was developed for CV prediction. NaOH pretreatment increased the CV from 11.38 MJ/kg to 12.79 MJ/kg (a 12.9 % improvement). The FTIR analysis revealed a C–O stretch difference of 4 cm−1, while the SEM analysis revealed morphological restructuring. The correlation-based parameter profiling revealed fixed carbon (FC) as the only positively correlated parameter with CV. The FIA revealed FC as the most influential predictor of energy content with a Gini index of 0.821, while PCA further confirmed FC’s dominance in driving calorific performance. The GP-clustered ANFIS-PSO model with triangular membership functions outperformed other configurations with high accuracy (RMSE = 0.1070, MAPE = 7.354 %, MAD = 0.0828, and MAE = 0.0895). This research contributes valuable insights into optimizing solid biofuel combustion properties through pretreatment strategies, supported by advanced computational, data-driven and neuro-fuzzy techniques. HIGHLIGHTS • Alkaline pretreatment (0.5 % NaOH) improved CV by 12.9 % from 11.38 to 12.79 MJ/kg. • SEM and FTIR confirmed NaOH pretreatment-induced fiber delignification and porosity. • Fixed carbon (FC) emerges as the dominant driver of energy with a GI-value of 0.821. • PCA shows that 98% of the data variance is captured in PC1 with FC as the dominant feature. • GP-ANFIS-PSO model achieved the best CV prediction with RMSE of 0.1070 and R2 of 0.932.
Impact of preschool hearing screening in low-income communities : program outcomes and caregiver perspectives
(American Speech-Language-Hearing Association, 2025-04) Odendaal, Tara; Le Roux, Talita; Swanepoel, De Wet; dewet.swanepoel@up.ac.za
PURPOSE : This study aimed to describe the impact of a preschool hearing screening program in a low- and middle-income country (LMIC) in terms of referral outcomes and caregiver perspectives. METHOD : This study included two components. First, a review of outcomes from a large-scale community-based hearing screening program, facilitated by community health workers (CHWs), for preschool children who failed their hearing screening. Second, telephonic surveys were conducted with (a) 25 caregivers whose children attended follow-up appointments and were diagnosed with hearing loss and (b) 33 caregivers whose children did not attend follow-up appointments. RESULTS : Over 21 months, 13,322 children underwent hearing screening, with an initial referral rate of 6% (809). Follow-up tests at preschools covered 86.2% (697) of children who failed the initial hearing screening, of whom 47.8% (387) presented with hearing loss and were referred for further evaluation. Among the 190 attending follow-up appointments, 54.8% (104) were diagnosed with hearing loss. Of these, 71.1% (74) had conductive hearing loss, 12.5% (13) had sensorineural hearing loss, and 13.5% (14) had mixed hearing loss. Caregivers strongly supported (96%) community-based hearing screening for preschool-aged children. Notably, attendance varied significantly between preschool rescreenings (86.2%) and health care facility follow-up appointments (49.1%). Caregivers highlighted barriers to attend hearing services including work commitments, long waiting times at health care facilities, miscommunication about referrals and appointments, relocations, and COVID-19 appointment cancellations. CONCLUSIONS : This study highlights the effectiveness of community-based hearing screenings in LMICs, led by CHWs. It emphasizes strong caregiver support and the importance of culturally relevant communication. Challenges in follow-up attendance persist, emphasizing the need for improved accessibility and communication within health care systems. Prioritizing caregiver concerns and promoting culturally sensitive education are essential for improving outcomes.
Adsorptive and photocatalytic remediation of greywater in wastewater : a review
(Springer, 2025-03) Sanni, Saheed O.; Pholosi, Agnes; Pakade, Vusumzi E.; Brink, Hendrik Gideon
Bathroom, and laundry greywater (GW) components are considered significant urban wastewater and are classified as hazardous substances that contaminate groundwater resources. Thus, achieving permitted levels for GW before discharging into the environment requires the removal or reduction, which has become a challenge. Various techniques have been developed to decontaminate GW from wastewater, comprising biological, chemical, filtration, adsorption, membrane separation, and photocatalytic degradation. Due to the simplicity, cost-effectiveness, abundance of materials, and capacity for facile scaling-up for remediation purposes, adsorption and photocatalysis technologies have been widely utilized in GW wastewater treatment. This review thus first explains the sources of GW and components found within this particular wastewater, which are critical for removal. The second part reviews various adsorbents or photocatalysts, including materials of macro, micro, and nanosize utilized for GW treatment. The review highlights the significance of activated carbon among all adsorbents under adsorption technology reviewed with the highest removal rate of chemical oxygen demand (COD), and biochemical oxygen demand BOD in GW. Moreover, the doped titanium dioxide photocatalyst also presented significant removal of COD, and BOD in GW within a shorter space of time. The impact of surface area and chemical functionalities of the adsorbent, and whilst aspect of nanostructure and absorptivity of photocatalyst in the visible region of the solar spectrum on the expedited removal of GW was also highlighted. Furthermore, this review emphasizes photocatalyst nanomaterial achieving a complete mineralization of different components present in GW, into mineral products.
Expanding role for gallium-68 PET imaging in oncology
(Elsevier, 2024-11) Kleynhans, Janke; Ebenhan, Thomas; Sathekge, Mike Machaba
Please read abstract in the article.
Prevalence, symptomology, and correlates of curable sexually transmitted infections among pregnant women in Eastern Cape, South Africa
(Sage, 2025) Shaetonhodi, Natalie G.; De Voux, Alex; Babalola, Chibuzor M.; Davey, Dvora Joseph; Mdingi, Mandisa M.; Gigi, Ranjana M.S.; Peters, Remco P.H.; Mukomana, Freedom; Klausner, Jeffrey D.; Medina-Marino, Andrew
BACKGROUND: Curable sexually transmitted infections (STIs) contribute to adverse maternal and neonatal outcomes. Syndromic management is standard care in South Africa. We evaluated prevalence, symptomology, and correlates of curable STIs, among pregnant women in Eastern Cape, South Africa. METHODS : We conducted a cross-sectional analysis using baseline data from a randomized controlled trial of pregnant women attending their first antenatal care visit at public clinics in Buffalo City Municipality (2021–2024). Participants were tested for Chlamydia (C.) trachomatis, Neisseria (N.) gonorrhoeae, Trichomonas (T.) vaginalis using GeneXpert point-of-care tests and for syphilis using Alere Determine TP rapid test. Symptoms were self-reported and clinically-observed. Adjusted prevalence ratios were estimated using Poisson regression models with robust standard errors. RESULTS : Among 1491 participants (median age: 28 years (IQR: 24–33); gestational age: 13 weeks (IQR: 8–18); HIV prevalence: 30%), STI prevalence was 27.6% (95% CI: 25.3–29.9): C. trachomatis 14.7%, N. gonorrhea 5%, T. vaginalis 10.2%, syphilis 3.4%. Women with HIV had higher STI prevalence (32.8% vs 25.3%, p = .003), particularly for T. vaginalis (17% vs 7.3%, p < .001); 20.1% of women with C. trachomatis, N. gonorrhea, and/or T. vaginalis were symptomatic, and 63% of symptomatic women tested STI-negative. Younger age, lower education, multiple sex partners and unknown HIV-serostatus of partners were associated with increased STI prevalence. CONCLUSION : We observed a high prevalence of STIs, particularly among women with HIV, with many asymptomatic cases; emphasizing the need for integrated point-of-care testing to ensure timely treatment, reduce antibiotic overuse, and improve maternal and neonatal outcomes.
Forecasting real housing price returns of the USA using machine learning : the role of climate risks
(Inderscience, 2025-07) Sales, Bruno Tag; Torrent, Hudson S.; Gupta, Rangan
Climate change, a pressing global challenge, has wide-ranging implications for various aspects of our lives, including housing prices. This paper delves into the complex relationship between climate change and real housing price returns in the USA, leveraging a comprehensive dataset and advanced machine learning technique - the stepwise boosting method. This ensemble learning technique significantly enhances our analysis. Our findings suggest that climate change variables can influence real housing price returns, particularly in the short term, but the relationship is complex and varies by region. The adaptive learning capability of step-wise boosting has been crucial in uncovering these insights. This methodological approach not only underscores the importance of employing advanced predictive models in analysing the effects of climate change on urban development but also highlights the potential for informed decision-making, sustainable urban planning, and climate risk mitigation.
Increasing aridification calls for urgent global adaptive solutions and policy action
(Nature Research, 2025-05) Pricope, Narcisa G.; Vicente-Serrano, Sergio M.; Toreti, Andrea; Ocampo-Melgar, Anahi; Spinoni, Jonathan; Moran-Tejeda, Enrique; Archer, Emma Rosa Mary; Diedhiou, Arona; Ravindranath, Nirajalli; Mesbahzadeh, Tayebeh; Pulwarty, Roger S.; Alibakhshi, Sara
Aridification threatens over 2.3 billion people by reshaping landscapes and increasing socio-economic vulnerabilities, demanding immediate policy actions and global cooperation to enhance resilience and develop transformative solutions.
Co-creation of strategies and interventions to improve mobile-linked point-of-care diagnostics user experience in the South African context : nominal group technique
(Academic Journals, 2025-06) Nxele, Siphesihle RobinMoetlhoa, B., Dlungwane, T., Mathebula, E. M., Hlongwana, K. W., Dzobo, M., Jaya, Z., Duah, E., Kgatle, M., Maluleke, K., Dlangalala, T., Marange, M., Dzinamarira, T., Thabane, L., & Mashamba-Thompson, T.; Moetlhoa, Boitumelo; Dlungwane, Thembelihle; Mathebula, Evans Mantiri; Hlongwana, Khumbulani W.; Dzobo, Matthias; Jaya, Ziningi Nobuhle; Duah, Evans; Kgatle, Mankgopo; Maluleke, Kuhlula; Dlangalala, Thobeka Nomzamo; Marange, Musa; Dzinamarira, Tafadzwa; Thabane, Leha; MMashamba-Thompson, Tivani Phosa; sr.nxele@up.ac.za
User experiences are crucial for the sustainable development and implementation of mobile-linked point-of-care diagnostic technologies. The Nominal Group Technique (NGT) engages stakeholders to co-create strategies that improve the uptake of these technologies in community healthcare settings, particularly in disease-burdened and resource-limited contexts like South Africa. Stakeholders provide insights from social, economic, technological, and medical perspectives. The NGT was used at the REASSURED Diagnostics Symposium workshop, conducted in two phases: identifying potential barriers and developing strategies to address them. Data were collected via Google Forms and thematically analyzed, with themes ranked using a Likert scale from 1 (very low priority) to 7 (highest priority). Key challenges affecting user experiences included psychological issues, turnaround time, and connectivity. Top strategies to mitigate these challenges were health education and offline-capable technology. The NGT workshop facilitated the co-creation of practical strategies to enhance mobile-linked point-of-care diagnostics user experiences in South African healthcare settings.
Who conquered South Africa? Neocolonialism and economic sovereignty
(University of Wisconsin Press, 2024) Dladla, Ndumiso; ndumiso.dladla@up.ac.za
The right of conquest is a doctrine in the theory of international law in terms of which victory in war entitles the victor both to the title to territory of the vanquished as well as sovereignty over them. Far from being a mere event, however, conquest is an ongoing process, structure, and relation of domination. Despite the widely celebrated “transition to democracy” and the supposed triumph of popular sovereignty in South Africa in the past three decades, we argue that South Africa’s “democratic” constitutional order remains firmly rooted in the dubious right of conquest asserted since the defeat of its indigenous people in the unjust wars of Western colonization, which began in the mid-seventeenth century. In this article we critically reflect on South African historiography by asking “Who conquered South Africa”? The question is necessary because sovereign power is both misunderstood and obfuscated in South African contemporary history and public discourse. We argue that conquest, and its attendant concepts of sovereignty and war, are deliberately underemphasized in South African historiography despite being at the root of problems regarding economic sovereignty. Our argument considers the problem of succession to conquest, in terms of which both the title to territory and sovereignty over the conquered is transferred from the conqueror to another party who then enjoys these entitlements and powers. We trace various successors in title to Conquest South Africa, and show that their economic power originates in the right of conquest. Their ownership of South Africa’s natural resources originates in the title to territory acquired through its disseisin following the conquest of the indigenous people, and in the same way their continued de facto sovereignty over that population now takes the form of the wanton and relentless exploitation of their labor power.
A scoping review of the impact of the COVID-19 pandemic on family wellbeing in Africa
(Sage, 2025) Chigeza, Shingairai; Fadiji, Angelina Wilson; Matamela, Nyambeni A.; shingairai.chigeza@up.ac.za
Despite the immense interruptions to relationships and family life during the COVID-19 pandemic, only a few studies explicitly focused on family wellbeing. Therefore, the present study aimed to synthesize current evidence in the African context to provide a state-of-the-art representation of the pandemic's impact on family wellbeing. Using a scoping review, 22 articles on the impact of the COVID-19 pandemic on family wellbeing in Africa were analysed. The results of the study showed a diverse and immense impact of the pandemic on family wellbeing. We noted that there were few studies on this topic and that wellbeing outcomes were measured from a deficit perspective rather than as a positive state of being. The theme of stigma was more pronounced in Western Africa, whereas domestic violence was linked more to Southern African contexts. Furthermore, the economic impact of the pandemic was emphasized in Eastern and Southern African countries than in Ghana and Nigeria in Western Africa. In line with the recommendations from the articles reviewed, a multifaceted policy response is needed to protect family wellbeing. Such interventions need to focus on family functioning, happiness and social wellbeing, and not just reactive and preventative approaches, to promote wellbeing.
Circumventing Section 7(8)(a)(I) of the Divorce Act 70 of 1979 and Section 37D of the Pension Funds Act 24 of 1956 through strategic resignation : CNN v NN 2023 (5) SA 199 (GJ)
(Juta Law Journals, 2024-06) Maloka, Tumo Charles; Ramontja, Koma
Suppose that the High Court dissolved a couples’ marriage on 14 October 2022 and incorporated the parties’ signed settlement agreement in its order. Unbeknown to the divorce court and the wife, the husband had resigned from his employment and exited his retirement fund on 7 May 2021. This was roughly two months after being served with the divorce summons. For all practical purposes, when the court granted the divorce order, the husband was not a member of a retirement fund. Consequently, he did not have a pension interest from which the ex-wife could be allocated a portion (CNN v NN 2023 (5) SA 199 (GJ) para 4 (‘CNN’)). It transpired that at the time the divorce order was granted, the husband’s pension benefits were still held by the fund. Following the divorce order that assigned her 50 per cent of the husband’s pension interest, the ex-wife approached the fund with the aim of requesting payment of what she believed was due to her (CNN para 5). The fund advised her that the ex-husband’s pension benefit had accrued to him and that he was no longer a member of the fund. Furthermore, the fund informed her that the divorce order did not comply with the legislative prescripts and could not be enforced. In turn, the fund’s Divorce and Maintenance officer advised that for her to be assisted, she needed to provide the fund with a divorce order directing it to pay a pension benefit as opposed to a pension interest. Accordingly, what the fund was holding on behalf of the husband was his accrued pension benefit and his pension interest was nil. As a result, the divorce order could not be enforced (CNN para 5). The contents of the letter from the fund caused the ex-wife to launch an application to amend the divorce order which incorporated the settlement agreement by amending the phrase ‘pension interest’ and replacing it with ‘accrued pension benefit’ (CNN para 6).
Is the foreign business establishment lagging behind new business models? Commissioner for the South African Revenue Service v Coronation Investment Management SA (Pty) Ltd [2023] Zasca 10
(Juta Law Journals, 2023-12) Sengwane, Khodani
Controlled foreign company (CFC) rules are anti-avoidance rules to ensure the taxation of profits diverted offshore by South African residents (Van der Zwan, ‘Cross-border transactions’ in Stiglingh (ed), Silke: South African Income Tax (LexisNexis 2023) 889). The rules are concerned with avoidance schemes and are not meant to deter real cross-border transactions (Van der Zwan, ‘Cross-border transactions’ in Stiglingh (ed), Silke: South African Income Tax (LexisNexis 2022) 871–872). In terms of the rules, profits of a non-resident company may also be liable for tax in South Africa at the hands of its resident shareholder/s if the company is considered to be a CFC of such resident shareholder/s (s 9D of the Income Tax Act 58 of 1962 (Act)). A company will be considered to be a CFC if it is a foreign company where more than 50 per cent of the total participation rights or voting rights in that company are directly or indirectly held or exercisable by one or more residents (except headquarter companies) or the financial results of that foreign company are reflected in the consolidated financial statements (prepared in terms of International Financial Reporting Standards 10) of a resident company (s 9D of the Act).

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