Search Results (21,239)

The consequences of changing climate conditions and associated extreme weather are increasingly discussed in the global railway transport sector, as infrastructure damage and service disruptions are more widely reported. The Passenger Rail Agency of South Africa (PRASA) is a critical component of the national passenger rail service that provides safe, reliable and affordable rail services to millions of passengers annually. However, the increasing recorded frequencies of extreme weather events in the country means that PRASA’s operations and infrastructure are not exempt from these emerging hazards. This provided an opportunity for the study to assess the spatio-temporal exposure and climate risk of climate-related extreme weather events to PRASA infrastructure and operations. The study drew on the strengths of a mixed-methods approach, integrating quantitative and qualitative techniques. It combined recorded historical extreme-weather event data from the South African Weather Service (SAWS) with expert-based focus group discussions to address the research questions. Findings show an increase in the recorded frequency of extreme weather events over a period of 103 years (1920–2022) in both areas. These hazards indicate exposure that can lead to damage to physical rail infrastructure and to train service disruptions. In both areas, Kendall’s tau indicated significant positive monotonic trends in the frequency of several weather-related hazards over time. Focus group findings identified coastal flooding, flash floods and sea-level rise as the top priority climate-related risks for PRASA along other key infrastructure vulnerabilities. On this basis, the study recommends both rail infrastructure and operational adaptations. Full article

Rock bolt reinforcement governs underground excavation stability through the combined effects of embedment depth, installation pattern, and interaction with the evolving stress and structural environment. Despite substantial advances across mechanistic, empirical, numerical, discontinuum, dynamic, and field-based research traditions, no unified framework currently integrates these approaches across geological and stress regimes. Current practice, therefore, relies on design methods calibrated within specific contexts, producing optimisation outcomes that are model-dependent, metric-sensitive, and not reliably transferable across site conditions. This review critically synthesises evidence from 30 peer-reviewed studies organised into six analytical categories: mechanistic confinement frameworks, empirical classification systems, numerical parametric investigations, discontinuum- and discrete fracture network (DFN)-based optimisation studies, high-stress and dynamic performance analyses, and field-based performance evaluations. The synthesis establishes three principal findings. First, optimal bolt embedment is stress-regime-dependent; plastic-radius-based design logic is appropriate under moderate static conditions but becomes insufficient under high stress or dynamic loading, where energy absorption capacity and controlled yielding govern performance. Second, in discontinuous rock masses, joint geometry and spacing dominate reinforcement effectiveness, shifting optimisation from uniform length selection toward pattern-specific alignment and multi-length configurations that outperform equal-length grids under DFN-controlled conditions. Third, numerical optimisation outcomes are sensitive to the choice of objective metric and modelling paradigm, such that bolt length and spacing recommendations cannot be transferred across analytical frameworks without explicit mechanism comparison. To integrate these findings, a unified conceptual framework is proposed based on regime classification using three dimensionless indicators: the bolt penetration ratio (Π₁ = L/r_p), which relates embedment to plastic zone radius; the structural interception ratio (Π₂ = S/S_j), which relates bolt spacing to dominant joint spacing; and the stress intensity ratio (Π₃ = σ_in situ/σ_cm), which relates in situ stress to rock mass compressive strength. These indicators identify whether confinement-dominated, structure-dominated, or stress-dominated behaviour governs stability, and direct design logic accordingly. The framework does not prescribe universal geometric thresholds; rather, it provides a structured classification pathway that integrates mechanistic and empirical evidence into a coherent and transferable design logic. Probabilistic validation incorporating geological variability, stochastic fracture network modelling, and iterative field calibration is identified as the necessary development path toward a statistically robust optimisation methodology. Full article

In efforts to survey biting flies, there is a need for a multi-species trap that can capture diverse families of hematophagous flies, thus functioning as a more robust and representative trapping method. The current study evaluated the efficiency of the baited P38T BioFlyTrap with other standard traps, namely the H-trap used in South Africa, the Vavoua (West/Central Africa), and the Nzi (East Africa), in informing decision-making to undertake enhanced surveillance and control interventions against biting flies in South Africa. A comparative study was done using a 4 × 4 Latin Square Design (LSD) approach over a period of 16 days in northeastern KwaZulu-Natal. The H-trap was most efficient for Glossinidae, while the Nzi trap caught the most diverse species dominated by Tabanidae. The P38T BioFlyTrap showed moderate performance across all categories (Glossinidae, Tabanidae, Muscidae (Stomoxyini)) of biting flies. The Vavoua trap was the least effective trap for Glossinidae and Tabanidae, but was relatively effective for Stomoxyini. In this environment, baited P38T BioFlyTrap would be useful for broader spectrum surveillance, while baited H-trap and Nzi remain specifically more performant, respectively for Glossinidae and Tabanidae. Full article

Digital governance has increasingly emerged as a critical institutional mechanism for strengthening public administration, enhancing accountability, improving service delivery, and advancing inclusive development across Africa. Governments across the continent have expanded investments in e-governance systems, digital public infrastructure, artificial intelligence (AI)-enabled administrative systems, interoperable service platforms, and data-driven governance reforms as part of broader modernization and Sustainable Development Goal (SDG) agendas. Despite these developments, digital governance outcomes remain uneven and are frequently constrained by fragmented governance architectures, weak institutional coordination, administrative capacity deficits, regulatory limitations, and persistent socio-economic inequalities. To address these challenges, this study conducts a qualitative Systematic Literature Review (SLR) guided by PRISMA 2020 reporting standards to examine how digital technologies interact with governance systems, institutional structures, administrative capability, and socio-technical inequalities across African public sectors. The review synthesized 42 included studies published between 2015 and 2025 using structured Boolean search strategies, predefined inclusion and exclusion criteria, abductive thematic synthesis, and framework-oriented analytical procedures. The findings identify three interconnected governance constraints shaping digital transformation outcomes across African public sectors: fragmented and centralized governance arrangements; institutional and administrative capability deficits; and persistent digital inequalities and exclusionary governance systems. Although digital governance reforms demonstrate important potential for improving transparency, interoperability, citizen participation, financial inclusion, and administrative efficiency, sustainable transformation outcomes depend heavily on institutional coordination, adaptive governance systems, digital inclusion, regulatory effectiveness, and accountable AI governance arrangements. Building on the synthesized evidence, the study develops a decentralized AI-enabled digital public governance framework linking decentralization, interoperability, institutional coordination, digital inclusion, adaptive governance, and ethical AI governance to sustainable public-sector transformation outcomes. The study contributes theoretically by reconceptualizing digital governance as an institutionally embedded governance transformation process rather than merely a technological modernization agenda. The findings further contribute to sustainability debates by demonstrating how inclusive and decentralized digital governance systems can strengthen institutional resilience, public-sector innovation, and sustainable development outcomes across diverse African governance contexts. Full article

Digital assessment has become central to Open Distance e-Learning (ODeL), yet its implementation often assumes equitable access to digital resources, potentially disadvantaging students studying in diverse geographical and socio-economic contexts. This study examined how students’ living contexts influence their experiences of digital assessment in undergraduate mathematics education at a South African distance education institution. An explanatory sequential mixed-methods design was employed. Survey data were collected from 253 undergraduate students, with 251 participants included in the inferential analyses after excluding two respondents who selected “Other” as their living area category. Quantitative data were analysed using chi-square tests, binary logistic regression, and ordinal logistic regression, while qualitative responses were analysed thematically. The findings revealed that living context was significantly associated with reliable internet access, and internet reliability significantly associated with students’ experiences of typing and submitting digital assessments as well as their perceptions of assessment inclusivity. Qualitative findings further highlighted challenges relating to connectivity, device limitations, mathematical representation, and the need for more flexible assessment practices. The study advances Contextualized Digital Assessment as a conceptual framework for designing equitable digital assessment that recognises students’ diverse technological, geographical, disciplinary, and socio-economic realities. The findings provide practical guidance for higher education institutions seeking to design more inclusive and context-sensitive digital assessment within ODeL environments. Full article

Background/Objectives: Contemporary sport-related concussion management has shifted from prolonged rest toward early, symptom-limited activity and a staged return-to-sport strategy. The Amsterdam framework provides an essential safety hierarchy but does not fully operationalize how clinicians should manipulate exercise dose, task complexity, recovery, and interacting rehabilitation domains within each stage. This Perspective proposes neuroperiodization as a constrained, criterion-based load-prescription framework nested within the Amsterdam strategy. Framework Development: The framework distinguishes prescribed external load from internal response, including symptom change and duration, heart rate, rating of perceived exertion, task quality, confidence, and delayed recovery. Clinical decision-making is organized through a repeated cycle of assessment, prescription, monitoring, adaptation, and reassessment. Proposed Framework: Neuroperiodization supports the concurrent but controlled development of aerobic, cervical, vestibular–ocular, neuromotor, cognitive–motor, and sport-specific capacities. Progression remains subordinate to medical clearance, clinical findings, symptom response, and sport-specific risk. Conclusions: Neuroperiodization should be regarded as a conceptual clinical framework rather than a validated rehabilitation protocol or an alternative return-to-sport clearance pathway. It integrates Amsterdam consensus recommendations, evidence-informed extrapolations, and author-proposed elements and requires population-specific adaptation and prospective evaluation. Full article

The analysis of genetic gain and changes in economic traits among modern and older cultivars is important to estimate breeding progress, evaluate the effectiveness of selection methods, identify optimised and neglected attributes, detect trade-offs, and inform strategies in crop improvement programs. This meta-analysis analysed global genetic gain and changes in seed yield, yield-related traits, and seed compositional attributes in soybean (Glycine max [L.] Merr.). A meta-database comprising 272 genetic gain data points recorded from 29 studies and 2555 mean performances captured from 34 research papers was compiled from research reporting cultivars released globally between the 1920s and 2010s. The mean values extracted from these studies were subjected to the R-Software analysis of variance (ANOVA) to reveal the effects of year of cultivar release and production region on the studied agronomic and compositional attributes. Boxplots were constructed to visualise data distribution and variability, and Pearson correlation and principal component analysis (PCA) were performed to examine inter-relationships among the measured traits with year of cultivar release and production region. Significant differences (p < 0.001) in mean performance were found among decades of cultivar release for seed yield (SY), number of seeds per pod (NSPod), days to flowering (DTF), days to maturity (DTM), and total biomass (TB). Cultivars released in the 2000s attained the highest mean SY of 3737.62 kg ha⁻¹, compared to 2156.08 kg ha⁻¹ observed for varieties released in the 1960s. Annual mean increases for SY ranged from 1.75 to 47 kg ha⁻¹year⁻¹, driven primarily by improvements in number of seeds per plant (NSP), NSPod, plant height (PH), DTF, TB, and hundred seed weight (HSW). Conversely, seed protein content (SPC) declined across most breeding programs, while seed oil content (SOC) showed only modest improvement, and no consistent genetic gains were documented for micronutrient traits, including iron (Fe), zinc (Zn), calcium (Ca), or phytic acid (PA) content. Phytic acid, a potent chelator of essential minerals and a known inhibitor of protein digestibility in monogastric species, represents a critical but largely untracked compositional target in global soybean breeding. The absence of PA as a systematically monitored trait constitutes a significant gap in the literature, with direct implications for the nutritional quality of improved cultivars. Future breeding programs should adopt an integrated approach that simultaneously targets high SY, enhanced micronutrient bioavailability, and reduced antinutritional factor concentrations to advance both agricultural productivity and global food and nutrition security. Full article

Wind-energy expansion is indispensable to decarbonization, but a strong wind resource does not by itself establish that development is spatially suitable, socially legitimate or institutionally deliverable. This article develops an empirical spatial–legal screening framework that converts technical wind opportunity into Justice-adjusted Wind Development Potential (JAWDP). The analysis covers Australia, Brazil, Canada, Chile, China, Denmark, Germany, India, Kenya, Morocco, South Africa and the United Kingdom. A 25 km grid is used for the primary analysis and a 10 km grid for resolution sensitivity. The Wind-Resource Potential Index (WRPI) combines 100 m wind power density with grid remoteness; the Landscape-Conflict Index (LCI) combines protected-area coverage, ecological sensitivity, agricultural land, settlement exposure and cultural-heritage proximity; and the Legal and Justice Friction Index (LJFI) codes nine functional safeguards on a 0–2 scale. Equal component weights and a preregistered symmetric baseline of α = β = 0.25 are used in the multiplicative JAWDP model. The United Kingdom and Denmark rank first and second (0.702 and 0.697), followed by Morocco under a disclosed midpoint legal scenario (0.539). Grid-resolution changes leave ten country ranks unchanged and shift Chile and Germany by one position. Across the full preregistered sensitivity set, eleven countries are classified as stable and Germany as moderately stable. As an external plausibility check, JAWDP correlates with 2024 installed wind-capacity density (Spearman ρ = 0.692, p = 0.013) and 2015–2024 capacity-addition density (ρ = 0.699, p = 0.011). An additive equal-weight multicriteria benchmark produces only moderate rank correspondence (ρ = 0.559), illustrating the non-compensatory purpose of the justice adjustment. The framework is intended for comparative screening, not as a prediction of generation, a grid-feasibility model or a substitute for project-level legal review. Additional robustness checks show high stability to sample composition and transmission-vintage perturbation, but the deployment association weakens under wind-suitable-area denominators; the external comparison is therefore interpreted as a denominator-sensitive plausibility check rather than empirical validation. Full article

Lean Construction (LC) has evolved from an emerging adaptation of production principles into a mature academic domain, yet a comprehensive assessment of its global structure and development remains needed. This study presents a rigorous bibliometric and scoping review of LC research using a sample of 484 highly refined, peer-reviewed documents retrieved from the Scopus database up to 2025. Following the PRISMA-ScR guidelines and utilizing VOSviewer, the co-occurrence networks of keywords, countries, and co-authorships were systematically analyzed. The results reveal a structurally centralized research landscape historically led by the United States and the United Kingdom, though accompanied by an increasing globalization driven by emerging clusters in Asia and South America. Keyword analysis indicates growing research attention to Building Information Modeling (BIM), information management, agile approaches, and environmental sustainability within the analyzed Lean Construction literature alongside traditional operational and planning concerns. However, the literature exhibits persistent fragmentation, with over 70% of identified journals publishing two or fewer articles on the subject within specialized thematic niches. This study concludes that opportunities exist to further explore the relationship between Lean Construction and emerging digital technologies while strengthening cross-regional and interdisciplinary collaborations. These efforts may contribute to a more cohesive and globally representative understanding of the discipline and its role in improving efficiency and sustainability within the built environment. Full article

The increasing deployment of renewable energy resources in geographically remote locations has accelerated the need for efficient long-distance power transmission solutions. High-voltage direct current (HVDC) technology is widely recognized as a preferred option for transmitting large quantities of electrical power over long distances compared to conventional high-voltage alternating current (HVAC) systems. However, determining the most suitable HVDC termination point within an interconnected HVAC network remains a complex planning problem due to the presence of multiple feasible termination locations and competing selection criteria. To address this challenge, this paper presents a multi-criteria decision analysis (MCDA) methodology for the evaluation and ranking of potential HVDC termination points. The Analytic Hierarchy Process (AHP) is utilized to derive the weights of the evaluation criteria, while the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is employed to assess and rank the candidate alternatives. The proposed methodology is demonstrated through a case study involving the transmission of renewable energy from a remote generation source to a distant load center. The findings indicate that the AHP-TOPSIS framework is capable of effectively distinguishing among competing alternatives and identifying the most suitable HVDC termination point. The proposed approach provides a robust, transparent, and practical decision-support tool for power system planners involved in renewable energy integration and transmission network expansion planning. Full article

Power quality degradation in low-voltage (LV) distribution networks remains insufficiently documented in many rapidly urbanizing African cities despite its significant impact on electrical equipment, service reliability, and network operation. This study investigates the following research question: To what extent does the power quality of an urban low-voltage distribution network comply with international standards, and which network characteristics are most strongly associated with the observed disturbances? To address this question, an extensive field measurement campaign was conducted from October 2024 to February 2025 on five radial feeders supplied by the Babemba medium-voltage/low-voltage (MV/LV) substation in Lubumbashi, Democratic Republic of the Congo. Electrical parameters were monitored using a Class B Chauvin Arnoux Qualistar C.A. 8331 power quality analyzer and evaluated against internationally recognized power quality standards. The measurements revealed persistent power quality degradation characterized by chronic under-voltage, with prolonged voltage levels below 207 V, typical deviations ranging from −20% to −30%, and voltage dips reaching 70–80% of the nominal voltage during peak loading conditions. Power supply continuity was also severely affected, with a System Average Interruption Frequency Index (SAIFI) of 7.85 interruptions/year and a System Average Interruption Duration Index (SAIDI) of 491 min/year, while a medium voltage outage lasting approximately 48 h highlighted the limited resilience of the distribution system. Additional disturbances included phase voltage imbalance reaching 18%, neutral currents up to 327 A, and short-term flicker values (Pst) approaching 1.5, exceeding the recommended comfort threshold. Overall, the observed disturbances were associated with heterogeneous feeder loading conditions, network configuration, non-standard electrical connections, and documented physical deterioration of the infrastructure. This study provides a comprehensive field-based assessment of power quality and service continuity in an urban LV distribution network in the Democratic Republic of the Congo and offers a quantitative basis for prioritizing feeder reinforcement, phase balancing, infrastructure rehabilitation, and the establishment of continuous local power quality monitoring. Full article

Adsorptive interactions between adsorbents and toxic contaminants are significantly exploited to the advantage of water treatment goals. In this study, adsorptive interactions in aqueous solution between Pb (II) ions and a lowly toxic and structurally robust metal–organic framework, zinc-trimesate framework (Zn-H₃btc), were evaluated using thermodynamic, equilibrium and kinetic models to establish the capacity of the material to adsorb Pb (II) ions from water. Zn-H₃btc was synthesized by refluxing mixtures of zinc nitrate and trimesic acid in DMF solvent and characterized using FTIR, SEM, EDS, PXRD, TGA and DTG methods. Adsorption experiments were carried out on the basis of variation in initial concentration, contact time, pH, adsorbent dosage, and temperature. Langmuir isotherm was the best-fitting isotherm. The maximum monolayer adsorption capacity of Zn-H₃btc was 54.05 mg/g. Kinetic studies revealed a pseudo-second-order controlled adsorption process, and hence a chemisorption mechanism. The thermodynamic parameters, Gibbs free energy, ΔG, activation energy, E_a, sticking probability, S*, and isosteric heat of adsorption ΔH_x, indicated that the adsorption process was spontaneous and required a minimal energy barrier; however, it had a fairly large amount of isosteric heat (133.39 kJ/mol) released. The findings confirm the applicability of Zn-H₃btc as an adsorbent of Pb (II) ions in aqueous solution. Full article

Background: Wastewater and Environmental Surveillance (WES) has become a useful public health tool as an early-warning system revealing emergence/re-emergence of pathogenic diseases and spread of antimicrobial resistance (AMR). We characterized the taxonomic composition, relative abundance, and antibiotic resistance genes (ARGs) of wastewater-identified bacterial pathogens across socioeconomically and epidemiologically diverse sewerage catchments in Nairobi, Kenya—a key East African urban city representing a low- and middle-income country (LMIC). Results: Metagenomic analysis of Nairobi’s wastewater revealed distinct bacterial and antimicrobial resistance (AMR) profiles. Campylobacteraceae (52.5% ± 17.9%) and Bacteroidaceae (19.8% ± 9.9%) dominated the communities. While Arcobacter cryaerophilus was ubiquitous, Bacteroides fragilis and A. suis abundances varied by neighborhood socioeconomic status. We detected critical clinical pathogens—including Escherichia coli, Vibrio cholerae, Mycobacterium tuberculosis, and the ESKAPE species—alongside 207 distinct ARGs conferring resistance to 11 antibiotic classes. Both taxonomic and ARG compositions showed high spatial heterogeneity, with maximum variation in low-income areas. Temporal analysis captured shifting pathogen dynamics, and metagenomic abundances for Vibrio cholerae and Klebsiella pneumoniae were validated via qPCR. Conclusions: Our findings underscore the utility of WES as a scalable, non-invasive public health tool. By capturing community-level pathogen composition and AMR dynamics, WES bypasses the limitations of clinical diagnostic access, providing a vital early-warning system for underserved urban populations. To maximize its public health utility, environmental genomic signals must serve as actionable triggers for coordinated One Health responses, including targeted clinical diagnostics, localized antimicrobial stewardship reviews, proactive risk communication, and prioritized sanitation infrastructure upgrades. Full article

Non-methane volatile organic compounds (NMVOCs) in the atmosphere have garnered considerable attention worldwide because of their significance in atmospheric chemistry and their usefulness in identifying emission sources and chemical sinks. Despite the importance of VOCs, their routine measurement in the UK and across Europe is somewhat limited, and as such, there is limited information available regarding their sources, particularly in sensitive locations such as densely populated urban areas. In this study, hourly NMVOC concentration data measured between January 2015 and December 2023 were analyzed across four monitoring sites spanning an urban-to-rural gradient in England. The Marylebone and Eltham sites showed significantly higher concentrations of alkanes, alkenes, and aromatic hydrocarbons compared to the rural sites of Chilbolton and Auchencorth, with highest recorded VOC values of 29.9 ± 9.1 and 15.3 ± 4.3 µg m⁻³, respectively. Ethane (C₂H₆) and propane (C₃H₈) showed their highest ozone formation potential (OFP) levels at Marylebone Road, with the contribution of ethane to ozone formation ranging from 4% in Eltham to 8% in Chilbolton. This indicates that the emissions from vehicles and industries have a greater impact on the reactivity of these compounds. The potential source contribution function (PSCF) showed that the Marylebone and Eltham sites are mainly impacted by local traffic sources, while Chilbolton and Auchencorth receive VOC emissions from wider geographical areas. The COVID-19 lockdowns caused significant reductions in VOC concentrations at urban sites, which resulted in total VOCs declining by 26% at Marylebone Road and 11% in Eltham, while rural sites remained unaffected. The study results demonstrate new insights into NMVOC long-term temporal patterns and source identification across different UK environments, with important implications for air quality management and emission control policies. Full article

Mesophotic coral reef ecosystems (MCEs) support unique biodiversity and can act as refuges for species that also occur on heavily impacted shallow coral reefs. However, we still know relatively little about the physical and environmental structure of MCEs and the species that characterise them, especially within the Western Indian Ocean. To address this gap, we surveyed fish and macrobenthic assemblages between 10 and 100 m depth at three islands of the Comoros Archipelago using Baited Remote Underwater Video Systems (BRUVS). We also recorded temperature and photosynthetically active radiation (PAR) using a Conductivity–Temperature–Depth (CTD) probe. The structure of the fish assemblages was influenced by substrate type, relief and depth. More diverse fish assemblages were found on higher relief reefs, while low-diversity fish assemblages were associated with shallow sand and deeper low-relief sand/reef mosaic habitats. The reef fish assemblages delineated into three groups, corresponding to three depth zones: the photic zone (12–45 m), upper-mesophotic zone (45–62 m) and lower-mesophotic zone (63–98 m). The upper–lower mesophotic break aligned with the theoretical bottom of the euphotic zone at PAR1%_surface. Macrobenthic assemblages comprised scleractinian corals on photic reefs, which transitioned at PAR3.5%_surface to assemblages of non-light-dependent Octocorallia (soft corals and fans), Gorgonia (sea whips) and Antipatharia (black corals) on the mesophotic reefs. Scleractinian corals were found deeper in Comoros, which may confer greater resilience to climate change. The photic and lower-mesophotic reefs supported unique fish assemblages of depth specialist species, while the upper-mesophotic zone appeared to be a transition zone for fish assemblages. The presence of numerous large depth-generalist fishery species at depths > 50 m suggests that the mesophotic zone may be providing a depth refuge for fishery species that are overfished on shallow reefs. Our findings highlight potential resilience in the coral reef ecosystems of Comoros and illustrate the importance of mesophotic coral reefs in conservation planning. Full article