University of Johannesburg

This review entails a critical appraisal on the potential of plants as alternatives to synthetic chemicals for crop protection, aligning with the global shift towards green-based approaches in agriculture. Utilising a defined set of inclusion and exclusion criteria, 235 papers were extracted from Scopus. These articles were analyzed to address specific research questions related to plant-based biocontrol methods. Approximately 25% of the literature was published in journals such as "Industrial Crops and Products", "Journal of Agricultural and Food Chemistry", "Pest Management Science", and "Frontiers in Microbiology". Thematic analysis identified core focus areas, including the chemical properties of antifungal agents, bioactive compounds, environmental protection, and the use of fungicides. Italy and China emerged as countries with the most represented authors, while China, India, and USA led in scientific production, corresponding authors' publications, and citation impact. We identified 91 plant species from 28 families, notably from the Lamiaceae, with strong potential as biocontrol agents. The most promising plants were Platycladus orientalis (L.) Franco, Mentha piperita L., Foeniculum vulgare L., Coriandrum sativum L., and Allium ascalonicium L. This study offers valuable insights and practical applications in the field of plant-based biocontrol, thereby underscoring the relevance and efficacy of green-based approaches in contemporary agricultural practices. There is an increasing scientific interest in sustainable crop protection strategies and the potential of plant-based biocontrol agents in addressing biotic stresses in crops. Overall, this review contributes to the understanding of plant-based biocontrol for crop protection, providing a foundation for further research and application in sustainable agriculture.

Vaccine hesitancy is a public health concern in South Africa and internationally. Literature on vaccine hesitancy associates this with mistrust of the government. We present a qualitative analysis of opinions about COVID-19 vaccination expressed by South African Twitter (now X) users during the first year of the vaccine rollout in South Africa. We conducted a thematic analysis of 800 randomly selected tweets containing vaccine-related keywords, sampled from four time periods in 2021. We categorised comprehensible South African non-news tweets as pro-vaccination (24.75% of sample), anti-vaccination (20.25%) or ambivalent (4.5%), and then identified themes. Among pro-vaccination tweets, the most common themes were criticism of the government’s handling of vaccine procurement and the rollout; concerns that the vaccine was urgently needed and/or not being made available fast enough; and statements that vaccines were safe and/or effective against COVID-19. Among anti-vaccination tweets, the most common themes were claims that the vaccine was harmful or too risky; suspicion of the government’s intentions with respect to the vaccine it was offering the public; and opposition to mandatory or ‘forced’ vaccination. Criticism and mistrust of the government were present among both pro- and anti-vaccination tweets, though for different reasons. We discuss this in light of literature recommending trust-building as a response to vaccine hesitancy.

The aim of this study is to contribute to the research on life satisfaction by investigating the link between commuting time and life satisfaction in Russia. Using data from the Russia Longitudinal Monitoring Survey, we find that commuting is negatively and significantly associated with life satisfaction. Moreover, we document that the effect of commuting is stronger for married couples and respondents living in rural areas. An extended analysis based on interactive regressions shows that the negative incidence of commute time on life satisfaction is potentially fueled by income and marital status and mitigated by age and gender.

The discourse of political legitimacy of African governments has been one of the complex issues underlying political contestation. Narratives on lack of legitimacy has been centered on rejection of the authority of governments which would have acquired power as a result of either military coups or contested elections. In the Zimbabwean context, narratives of political legitimacy gained traction in in 2000 due to increasing political contestation necessitated by the intensification of multiparty democracy. The dynamics of the legitimacy discourse increased after November 2017 when the Zimbabwe Defense Forces executed a military operation codenamed Operation Restore Legacy. The operation marked the end of the Robert Mugabe administration and the rise of a new dispensation led by then vice president Emmerson Mnangagwa. Since then, even after holding harmonized elections in 2018 and 2023, the Mnangagwa administration continues to face criticism on the grounds of legitimacy. Against this backdrop, the major objective of this chapter is to analyze how the discourse of legitimacy has been used in the communication and characterization of power politics in the Zimbabwean context. This will be done through examining the discourses around the constitutionality of Operation Restore Legacy in relation to the means by which the new government acquired power. The main thesis of the chapter is that legitimacy as a concept is a rhetorical abstract that has been employed by groups and individuals in politics to push their narratives towards attaining, maintaining and defending power. Data for this chapter were gathered from a large evidentiary base of books and journal articles.

The chapter introduces this multi-authored edited volume whose focus is on governance, language policy and political communication in the sub-Saharan African context. As such, the centrality of language and communication in issues of governance is demonstrated, together with the inability of sub-Saharan African governments to deal with rampant challenges such as corruption, absence of the rule of law, underdevelopment and the dependency syndrome as emanating mainly from the language choices, the rationale for such linguistic choices and communication practices. Thus, the chapter argues that the missing link to effective governance and development in the sub-Saharan African region can only be found in language policies and the ideologies associated with them, with the former colonizers’ languages mostly remaining the preferred ones. The chapter outlines the structure of the book, which has three distinct Parts. Part I has four chapters dwelling on the general theoretical background, Part II has four chapters exploring the sociolinguistic situation of selected African countries and the five chapters in Part III provide a discourse analysis of selected politicians’ speeches.

Antimicrobial resistance poses a significant threat to public health, particularly in cholera treatment. The emergence of antibiotic resistance, coupled with the sharp decline in pharmaceutical companies developing new cholera antibiotics, is a cause for concern. We formulate a multidrug-resistant (MDR) cholera epidemic model that incorporates a stage-switching strategy between two antibiotics to reduce the magnitude of resistance. The model is analyzed mathematically, and sensitivity analysis of the reproduction number is performed using sub-reproduction numbers. Stability analysis of the cholera-sensitive-only and cholera-resistant-only equilibria is investigated using Centre Manifold Theory. The model is calibrated through Markov Chain Monte Carlo simulations in Stan, showing stability at equilibrium points, which is further verified through numerical simulations. The simulations demonstrate an inverse relationship between the number of MDR cholera cases and the number of individuals receiving second-line treatment for cholera. This study suggests that the correct use of antibiotics can effectively manage the emergence of antimicrobial resistance. From a public health policy perspective, these findings emphasize the importance of antibiotic stewardship programs and the need for policies that promote the responsible use of existing antibiotics while encouraging the development of new treatment options. Such measures could help mitigate the global burden of MDR cholera and prevent further escalation of resistance.

Untargeted metabolomics faces researchers with complex processing, analysis, and interpretation tasks. Here, we review computational tools from the perspective of information visualization and underpin its critical role and importance to the field.

The power supplied to the target during a sputtering process affects surface evolution. As such, the influence of sputtering power on the growth of titanium (Ti) thin films was studied. The Ti thin films were deposited using a direct current (DC) magnetron sputtering system from a pure Ti target on a glass substrate at varying sputtering powers of 15% (54.12 W), 30% (109.70 W), and 50% (188.17 W) of the maximum system capacity. The thin films were then characterised for topography using atomic force microscopy (AFM), morphology using a field emission scanning electron microscope (FESEM), and crystallinity using an x-ray diffractometer (XRD). Furthermore, fractal analysis based on the AFM imaging was undertaken to evaluate the growth mechanisms of the Ti thin films. The thickness, grain size, and roughness of the thin films increased with the deposition power. The samples were mostly amorphous, although at 30% and 50%, a weak peak of Ti (002) was observed via x-ray diffraction. The fractal dimension (Df) decreased with increasing power. The multifractality strength increased with increasing power. Based on the fractal study, Volmer-Weber and Stranski-Krastanov's modes describe the growth mechanism of Ti thin films deposited at varying sputtering power.

This paper explores the intersection of public administration and its administrative state, transnational and global policy, and international sports governance. We start by exploring autonomy and self-governance in international sport before sharing the structures, legal personalities, and nature of transnational private law interaction with international sport. The implications are illustrated through three examples. The first is the legal-policy interactions of the FIFA World Cup 2022 with Qatar. The second are new interactions of human rights with future World Cups and future Olympics. The third is the role of the Court of Arbitration for Sport and the World Anti-Doping Agency. This leads to three implications for administrative scholarship: lex sportiva implications for public administration, a stretching of the autonomy and self-governance concepts, and expanding the evaluation stage of a policy cycle to include the governance legacies of mega sports events.

This paper reviews recent developments in materials science and device physics of high-quality epitaxial films of the transparent perovskite La-doped barium stannate, La:BaSnO3. It presents current efforts in the synthesis science of epitaxial La:BaSnO3 films for achieving reduced defect densities and high electron mobility at room temperature. We discuss the scattering mechanisms and the route toward engineering defect-free epitaxial La:BaSnO3 heterostructures. By combining chemical surface characterization and electronic transport studies, special emphasis is laid on the proper correlation between the transport properties and the electronic band structure of La:BaSnO3 films and heterostructures. For application purposes, interesting optical properties of La:BaSnO3 films are discussed. Finally, for their potential application in oxide electronics, an overview of current progress in the fabrication of La:BaSnO3-based thin-film field-effect transistors is presented together with recent progress in the fundamental realization of two-dimensional electron gases with high electron mobility in La:BaSnO3-based heterostructures. Future experimental studies to reveal the potential deployment of La:BaSnO3 films in optoelectronic and transparent electronics are also discussed.

Golfers often face challenges in refining their swings, seeking cost-effective ways to enhance their techniques. Traditional coaching methods are costly and since they rely on the human eye, these techniques often miss important golf swing movements owing to the rapid pace of a golf swing. To address this shortcoming, an investigation into the potential of IMU sensors for the mapping of golf swings to aid both instructors and golfers was undertaken. Focusing on the leading shoulder's horizontal position relative to the club head, the study addresses two questions: determining whether IMUs can map a golf swing as well as determining the minimum IMU sensors required to track a golf swing. Thus, the goal of this pilot study was to identify if there are optimal placements for IMUs on the body. The premise is that by performing a consistent golf swing, golfers could improve their handicap. Thus, by tracking and visually displaying the phases of the golf swing, such data could aid in increased golf swing consistency by analysing not only the phases of the golf swing, but also the bodily movements. This pilot study relied on six participants who each repeatedly performed golf swings. IMUs were positioned in eight positions around the body from ankle to shoulder and several trials were conducted for each position. The results showed that IMUs were useful in tracking a golf swing; however, certain bodily positions, such as the hip, leading knee, and leading foot, did not yield meaningful data as compared to the other positions. The IMU data from the back and front of the wrist and the leading shoulder provided useful mappings of the golf swing, including the timing and intensity. Analysis of body posture angles, especially wrist flexion, hip, and shoulder rotation angles, offered valuable data that may be useful to both coaches and players. By discerning patterns in successful and unsuccessful swings, coaches could provide informed feedback to golfers, aiding golfers in refining their techniques. These findings demonstrate the potential of IMU sensors in golf instruction, offering a data-driven approach to enhance golfers' performance and consistency on the golf course.

Scopolin and scopoletin belong to the class of coumarins and have experimentally proven natural antioxidants. Natural antioxidants are crucial in mitigating the impact of oxidants in the human body through radical scavenging. Even though scopolin and scopoletin are proven antioxidants by experimental results, their antioxidant mechanisms still remained unexplained. In this study, Density functional theory (DFT) calculations were used to study the radical scavenging mechanisms of both scopolin and scopoletin using kinetic and thermodynamics parameters.

Aflatoxins are toxic secondary metabolites produced by Aspergillus species that infect staple foods like maize causing threat to public health and economic impacts. The use of atoxigenic Aspergillus species is considered one of the promising technologies to prevent aflatoxin contamination in maize. Tanzania approved the use of aflatoxin biocontrol (Aflasafe®) in 2018 and introduced it to eight districts. Adoption and effectiveness of this technology depend on many factors including application of pre- and post-harvest practices. There is scant information on awareness of biocontrol and factors which influence the adoption and effectiveness of this technology. A cross-sectional study was conducted in Tanzania to assess awareness and identify factors influencing adoption of the technology. Data was collected from 334 smallholder farmers in Kiteto and Chemba districts and analyzed using SPSS version 20; p-values < 0.05 using a two-tailed test were considered statistically significant. Results indicated 95.4% are not aware and that only 2.7% of the farmers had used biocontrol technology. The use of biocontrol was significantly associated with high income level (p = 0.001) and exposure to print media (p = 0.03) and radio (p = 0.008). The use of hybrid seed (p = 0.01), grazing (p = 0.017), and rotation of crops on yearly basis (p = 0.024) were also significantly associated with the use of biocontrol. Income limits the use of biocontrol, requiring government subsidies for Aflasafe and a premium market for aflatoxin-free maize. Aflatoxin awareness and sensitization on adherence to good pre-harvest practices should be emphasized to enhance adoption of the technology.

This computational study delves into the influence of Bi2O3 concentration on the x-ray shielding capabilities of (x)Bi2O3 + (55-x)B2O3 + 15TeO2 + 10MgO + 20BaO, with x ranging from 0 to 40 mol%. The investigation revealed that higher Bi2O3 content leads to increased linear attenuation coefficient (LAC), mass attenuation coefficient (MAC), and effective atomic number (Zeff). Conversely, the half-value thickness (HVT), tenth-value thickness (TVT), and mean-free path (MFP) decrease as Bi2O3 concentration rises. Furthermore, the study noted a linear increase in LAC with Bi2O3 mol% at 16%, 3%, and 12% per mol% in the 15-30 keV, 40-80 keV, and 100-300 keV energy ranges, respectively. Thus, the (x)Bi2O3 + (55-x)B2O3 + 15TeO2 + 10MgO + 20BaO glass configuration demonstrates the promising potential for x-ray shielding, particularly effective for energies below 40 keV and above 80 keV, with efficacy increasing with higher Bi2O3 concentrations.

As efforts intensify to address the environmental impact of agricultural waste, the valorization of Manihot esculenta peel (MEP) for sustainable engineering applications presents a unique opportunity to repurpose this class of agricultural waste to achieve environmental sustainability development goals while promoting socio-economic development of this pollutant. The inherent properties of MEP, such as its richness in carbohydrates and cellulose, make it a useful raw material for producing biofuels, bioethanols, biocomposites, and other sustainable engineering materials. Its resilience to adverse environmental conditions also makes MEP well-suited for cultivation in diverse agroecological settings, further enhancing its appeal as a sustainable resource. While existing review articles provide valuable insights into Manihot esculenta peel utilization across various industries, they often overlook the comprehensive valorization of Manihot esculenta for sustainable engineering applications, creating a notable knowledge gap. Through a systematic examination of innovative approaches documented in the literature, this research seeks to bridge this gap by elucidating strategies for repurposing cassava waste into valuable engineering materials to mitigate environmental pollution and promote sustainable resource utilization. By synthesizing existing research and identifying key research gaps, this study advances the understanding of Manihot esculenta peel’s potential as a sustainable material and facilitates the transition toward greener engineering practices.

Background The aging population in the USA is projected to increase significantly, with a corresponding rise in dementia cases, particularly among racial minorities. This study examines the key drivers of racial disparities in dementia risk among older Black adults in the St. Louis area, a region characterized by entrenched structural racism. Utilizing a Community-Based System Dynamics (CBSD) approach, we engaged cognitively normal Black adults (age ≥ 45) to explore the complex interplay of social and structural determinants of health (S/SDOH) affecting dementia risk. Methods Eight CBSD workshops were conducted, during which participants identified and analyzed various factors influencing dementia risk through group model-building techniques. These workshops revealed multiple reinforcing and balancing feedback loops, highlighting the intricate relationships between trauma, health literacy, social isolation, education, healthcare access, and systemic racism. Results There were 59 participants with an average age of 64, a majority of women (88%) and college-educated (15.9 years) residing in areas with moderately severe deprivation. The resulting Causal Loop Diagrams underscored the impact of poverty, discrimination, and limited access to quality education and healthcare on dementia risk across the lifespan. Participants proposed actionable interventions, including health information campaigns, community mobilization, and improvements in public transportation and healthcare accessibility. Conclusion This study emphasizes the necessity of addressing S/SDOH to mitigate dementia risk among Black Americans. The findings call for targeted public health initiatives and policy changes to improve socioeconomic conditions and reduce racial disparities in dementia outcomes.

The growing concerns regarding the depletion of fossil fuels, CO2 emissions, and the effects of climate change prompt the usage of plug-in electric vehicles (PHEVs) all over the world in a big way. The increased electrical demand brought on by the charging of electric vehicles puts a burden on the distribution network parameters like energy loss, voltage profile and thermal limits. Recently, renewable energy-based distribution generation (RDGs) units are firmly integrated with the transmission and distribution system networks to lower the carbon footprint generated due to conventional thermal power plants. In addition, Battery Energy Storage Systems (BESS) are used to enhance grid operation and lessen the consequences of the high intermittency nature of RDGs power. In this work, two charging methods of PHEVs are considered: charging electric vehicles at home during night-time and charging electric vehicles at public fast charging stations (PFCS). The uncertain nature of arrival time and trip distance of PHEVs are addressed using probability density functions (PDFs). The 33-bus test system consists of commercial, industrial and residential buses is taken to implement the proposed methodology. In this work, 500 PHEVs are taken into consideration. The aforementioned charging methods produce a 24-h electric demand for PHEVs, which is then placed on the corresponding distribution system buses. The effect of PHEVs on technical distribution system metrics, including voltage profile and energy loss, is investigated. To improve the above metrics, optimal planning of inverter-based non-dispatchable PV units and dispatchable PV-BESS units in the distribution network by the inclusion of PHEVs electric load demand is addressed. The Pareto-based meta-heuristic multi-objective chaotic velocity-based butterfly optimization method (MOCVBOA) is chosen for optimization of desired objectives. The results of the MOCVBOA optimization algorithm are compared with those of the other optimization algorithms, NSGA-II & MOBOA, frequently described in the literature to assess its effectiveness.