Rhodes University is a public research university located in Makhanda (Grahamstown) in the Eastern Cape Province of South Africa. It is one of four universities in the province. Established in 1904, Rhodes University is the province's oldest university, and it is the sixth oldest South African university in continuous operation, being preceded by the University of the Free State (1904), University of Witwatersrand (1896), University of South Africa (1873) as the University of the Cape of Good Hope, Stellenbosch University (1866) and the University of Cape Town (1829). Rhodes was founded in 1904 as Rhodes University College, named after Cecil Rhodes, through a grant from the Rhodes Trust. It became a constituent college of the University of South Africa in 1918 before becoming an independent university in 1951.The university had an enrolment of over 8,000 students in the 2015 academic year, of whom just over 3,600 lived in 51 residences on campus, with the rest (known as Oppidans) taking residence in digs (off-campus residences) or in their own homes in the town.
Early detection of fruit fly (Diptera: Tephritidae) infestation in traded fruit is important for maintaining phytosanitary security, particularly for quarantine pests. This study evaluated the integration of micro-focus X-ray computed tomography (µCT) and deep learning as a non-destructive, automated, and scalable solution for postharvest pest detection. The Mediterranean fruit fly (medfly), Ceratitis capitata Wiedemann, 1824, was used as a model species and Navel oranges, Citrus sinensis (Osbeck), served as the host commodity. Controlled infestation experiments were conducted using both artificially punctured fruit to promote oviposition and intact fruit to avoid confounding effects associated with mechanical damage. Oranges were exposed to varying adult medfly densities to generate different infestation levels. Following exposure, the infested oranges were subjected to varying incubation periods to simulate different infestation stages. High-resolution µCT scans were first assessed manually and subsequently analyzed using a staged deep learning pipeline incorporating convolutional neural networks (CNNs), 3D CNNs, CNN-Long Short-Term Memory (LSTM) hybrids and Transformer-based models. Manual μCT inspection achieved mean correct classification rates of 0.84 in punctured fruit and 0.69 in intact fruit, with detection performance increasing with infestation stage. Deep learning analyses were conducted on a curated punctured-fruit dataset using a slice-level classification and voting-based aggregation strategy. Among the evaluated transfer-learning architectures, DenseNet121 achieved the best overall performance, reaching an accuracy of 0.88, a precision of 0.86, a sensitivity of 1.00, and an AUC of 0.80; because the manual and automated analyses were performed on different sets of fruit, these accuracies are complementary rather than directly comparable.Grad-CAM and attention visualizations confirmed that model predictions were driven by biologically meaningful tissue regions associated with larval damage. Although the deep learning workflow was developed and validated only on punctured fruit, the results demonstrate that μCT images contain sufficient information for automated detection of medfly infestation when infestation-associated damage is visible. These findings support the potential of combining μCT imaging and artificial intelligence (AI) for automated, reproducible and non-destructive postharvest pest detection and enhanced phytosanitary compliance in postharvest supply chains.
The fruit-piercing moth, Serrodes partita (Fabricius), is an economically important pest of citrus and other commercial fruit in South Africa, particularly during outbreaks. Adults puncture fruit to feed, causing direct damage and fruit decay. Other fruit-feeding moth species may also be attracted to damaged fruit, contributing to the overall fruit-feeding moth complex. This study evaluated bait types, bait presentation methods and trap designs to develop an effective trapping system for S. partita and other fruit-feeding moths under citrus orchard conditions. Fresh banana consistently outperformed the synthetic and banana-derived attractants evaluated. In the bait trial, fresh banana captured approximately 4.2-, 5.0-, and 25.0-fold more S. partita than banana essence and two Australian proprietary synthetic bait formulations, respectively. Combining banana with agar maintained its attractiveness to other fruit-feeding moths, with captures approximately 1.8- and 2.2-fold higher than those for fresh banana and banana formulated with a superabsorbent polymer, respectively. Funnel traps consistently outperformed bucket, delta and disc traps. Modification of the funnel trap with an electric grid further increased captures of other fruit-feeding moths approximately 4.3-fold relative to conventional funnel traps. These results demonstrate that fresh banana and banana and agar combined are effective attractants, and that the funnel trap is the most effective trap design of those investigated. These relatively simple and potentially low-cost components provide a practical basis for improved monitoring of fruit-feeding moths and for managing outbreak populations in commercial orchards.
Solar photovoltaic (PV) systems can provide a clean and sustainable alternative to fossil fuel energy, but the uptake of solar PV systems is often constrained by perceived and actual barriers. Despite South Africa's very high solar generation potential, solar PV adoption remains low, accounting for less than 10% of the country's energy mix. Central to renewable energy debates is making sure that the transition is equitable, affordable, and inclusive. Yet, despite high levels of inequality, there is no empirical standing on the factors hindering solar PV adoption among a socially differentiated household gradient. Using household interviews, the study investigated barriers to solar PV adoption across an income gradient in four towns located in the Eastern Cape province of South Africa. Results showed that significantly more high-income (82%) than low-income (63%) households had considered solar PV adoption, primarily to mitigate power cuts (89%). Both income groups were constrained by financial, institutional, and social barriers, but low-income households were disproportionately affected. While 86% of high-income households cited initial financial constraints, low-income households were nearly twice as likely to worry about high maintenance costs (48% vs. 26%) and system unfamiliarity (36% vs. 14%). High-income respondents were more concerned with institutional and technical barriers, such as a lack of supportive policies and grid-feed difficulties. Nearly all (98%) low-income households lacked knowledge regarding solar PV system capacity, compared to 60% for high-income households. Altogether, the results highlight that heterogeneity matters in our understanding of barriers to solar PV adoption and should be a key consideration in designing differentiated approaches to address barriers and ensure equity in renewable energy adoption.
Abstract This perspective paper examines transition pathways that move small‐scale fisheries from vulnerability towards viability. We understand ‘vulnerability to viability transition pathways’ as integrative and one that extends beyond economic concerns to include social, political, cultural and ecological aspects of small‐scale fisheries. Our findings draw on a reflexive and qualitative assessment of country‐specific case studies from across Africa and Asia to collaboratively identify transition pathways reflected in these contexts. Common pathways that emerged included: (1) building governance networks and partnerships; (2) centring small‐scale fisheries tenure and rights; (3) advancing a gender and intersectional perspective on viability pathways; (4) enhancing opportunities for ecologically sensitive and diversified livelihoods; and (5) co‐creating and co‐producing the knowledge required to catalyse transition pathways. Outcomes of this analysis provide context‐specific foundations upon which to further co‐develop a research agenda on small‐scale fisheries vulnerability to viability transitions. Insights from this analysis also contribute to the identification of the transdisciplinary capacities needed to build more viable and resilient small‐scale fisheries in the context of ongoing debates about blue economy expansion, and in relation to country‐level commitments to implement provisions of the FAO small‐scale fisheries guidelines. In advancing a vulnerability to viability pathways lens, this paper frames small‐scale fisheries transitions as governance‐mediated, justice‐oriented, relational and inherently non‐linear processes. Read the free Plain Language Summary for this article on the Journal blog.
Analogues of tadalafil, an FDA-approved inhibitor of human phosphodiesterase 5, have been reported to block the growth of human Plasmodium falciparum in vitro. Herein, we synthesized and evaluated 56 tadalafil analogues prepared as pure diastereomers. Some of the analogues showed potent antiplasmodial activity at nanomolar concentrations with selectivity indices >20-250 in vitro. Compound 33 was the most potent analogue, with an IC50 of 80 nM against cultured parasites and an IC50 > 20 μM on HeLa cells, resulting in a selectivity index >250. Several compounds were tested for potential inhibition of synthetic malaria pigment (β-hematin) formation and PfIspD (2-C-methyl-d-erythritol 4-phosphate cytidylyltransferase); it is possible that compounds 2 and 4 act by disrupting hemozoin formation whereas none of the tested analogues acted as PfIspD inhibitors. Metabolomic profiling revealed that some analogues strongly affect hemoglobin catabolism yet principal component analysis grouped them separately, suggesting differences in their antiplasmodial mechanisms of action.
