Search Results (38)

This paper examines the impact of different oil price benchmarks on the revenue profile of OPEC countries from 1990 to 2024. While there are prior studies on this subject, most of these studies adopted a symmetrical approach, overlooking the asymmetric effects of price shocks on government revenues. Additionally, prior research often aggregates oil price benchmarks, simplifying the complex dynamics influencing OPEC revenues. This study fills these gaps by evaluating both symmetrical and asymmetrical responses of the revenue profiles of OPEC countries to major global oil price benchmarks—NYMEX WTI, ICE Brent, DME Oman, and the OPEC reference basket. The study employs linear and nonlinear panel (ARDL) models on annual data from 1990 to 2024. The linear ARDL results indicate that government revenues respond positively to ICE Brent, NYMEX WTI and OPEC spot prices but negatively to DME Oman prices. The nonlinear ARDL model reveals asymmetric responses: revenue is more sensitive to negative shocks in ICE Brent and OPEC prices, while DME Oman price increases reduce revenues. Notably, NYMEX WTI fluctuations have minimal impact. The main conclusion of the paper is that OPEC’s fiscal stability is highly vulnerable to asymmetric, long-run oil price shocks. The study recommends policymakers adopt benchmark-specific fiscal hedging strategies, such as put options, and strategically diversify export markets to mitigate risk. Full article

Introduction: Polio supplementary immunisation activities (SIA) are implemented to rapidly increase vaccination coverage and interrupt the transmission of poliovirus in a specified geographical area. Polio SIA complements routine immunisation and is crucial for the eradication of the disease by increasing population immunity. However, several contextual factors (i.e., implementation determinants) can influence the success or failure of polio SIA implementation; as such, understanding their dynamics can enhance proactive planning for practice improvement. This study aimed to explore and map the contextual factors of polio SIA implementation in the African region using a critical systems thinking approach. Methods: A rapid review of published and grey literature was conducted. The search included the Global Polio Eradication Initiative library for programmatic reports and two databases (PubMed and Google Scholar). Data extraction was performed using a structured tool. Thematic analysis was performed to categorise the identified contextual factors according to the domains and constructs of the Consolidated Framework for Implementation Research (CFIR). Then, a causal loop diagram (CLD) was used to map the linkages between the identified factors. Results: A total of seventy-eight contextual factors across the five CFIR domains were identified: three for innovation, twenty for outer setting, sixteen for inner setting, twenty-six for individuals, and thirteen for the implementation process. A system map of all the factors using CLD revealed multiple contingent connections, with eleven reinforcing loops and four balancing loops. Conclusions: This study identified the multilevel nature of the contextual factors that influence polio SIA, including their dynamics. The integration of CLD and CFIR in this study offers critical insights into the potential feedback loops that exists between the contextual factors which can be used as leverage points for policy and practice improvements, including tailoring strategies to enhance polio campaign implementation effectiveness, especially with the expanded use of the novel Oral Polio Vaccine type 2 (nOPV2) across countries in the region. Full article

This paper addresses the critical issue of selecting the optimal solar tracking configuration for maximum energy generation, given the increasing demand for sustainable energy solutions in information and communication technology (ICT) facilities. The main goal is to thoroughly evaluate and compare seven different solar tracking configurations across technical, economic, and environmental dimensions: No Tracking (NT), Monthly Adjusted Horizontal Axis (MAHA), Weekly Adjusted Horizontal Axis (WAHA), Daily Adjusted Horizontal Axis (DAHA), Continuously Adjusted Horizontal Axis (CAHA), Continuously Adjusted Vertical Axis (CAVA), and Dual Axis with Continuous Adjustment (DACA). This study utilizes the HOMER simulation program to evaluate its energy and hydrogen production, emissions, and cost-effectiveness performance. Key findings indicate solar tracking improves energy efficiency, with optimal capacity factors of 18.2% and 17.7% for CAHA and DAHA configurations, respectively. Although load-following strategies increase reliability, there is a trade-off between capital costs and energy costs. In addition, an MCDM approach helps to consolidate the evaluation, resulting in CAVA being ranked as the most preferable option. The study contributes to informed decision-making for energy systems in ICT facilities by emphasizing the significance of considering a variety of criteria and evaluation techniques to address complex energy challenges. Full article

Hepatitis B virus (HBV) and Hepatitis C virus (HCV) contribute significantly to morbidity and mortality among drug users in Asia. This study systematically reviews and analyzes the pooled prevalence of HBV and HCV, considering geographic and methodological variations. A meta-analysis following PRISMA guidelines included data from PubMed, Scopus, and Google Scholar on studies on HBV or HCV or a combination of both within Asia. A random-effects model estimated pooled prevalence, with subgroup analyses by region, study design, diagnostic method, and publication year. A total of 112 studies were analyzed. The pooled HBV prevalence among drug users was 14.3% (95% CI: 11.5–17.6), highest in Malaysia (28.7%) and Vietnam (26.6%). HCV prevalence was 58.6% (95% CI: 54.0–63.0), with the highest rates in Vietnam (63.5%) and China (62.9%). Retrospective studies reported a higher prevalence than cross-sectional ones. The use of ELISA for initial screening followed up by PCR reduced heterogeneity, improving diagnostic accuracy. HBV prevalence declined after 2010, while HCV rates remained persistently high. The high burden of HBV and HCV among drug users in Asia underscores an urgent public health concern. Targeted interventions, including vaccination, harm reduction strategies, and improved access to antiviral treatments, are essential to curbing transmission and enhancing health outcomes. Full article

The COVID-19 pandemic has increased the interest in the use of wastewater-based surveillance (WBS) strategy for infectious disease monitoring, especially when clinical cases are underreported. The excretion of monkey virus (MPXV) in the feces of both symptomatic and preclinical individuals has further driven the interest in WBS applicability to MPXV monitoring in wastewater to support its mitigation efforts. We performed a systematic review with meta-analysis, using six databases to assess MPXV detection in wastewater. We performed a random-effects model meta-analysis to calculate the pooled prevalence at a 95% confidence interval (95% CI). Also, we carried out a subgroup analysis according to the country regions and a sensitivity analysis excluding studies classified as having a high risk of bias. The overall MPXV positivity rate in wastewater was estimated at 22% (95% CI: 14−30%; I² = 94.8%), with more detection rate in North America (26%, 95% CI: 8–43%) compared to Europe and Asia (22%, 95% CI: 12–31%). The MPXV detection rate was significantly higher in 2022 studies (22%, 95% CI: 13–31%) compared to 2023 (19%, 95% CI: 14–25%). The real-time PCR platform significantly detected more MPXV (24%, 95% CI: 14–34%) than the digital droplet PCR-based studies (17%, 95% CI: 4–31%), which was used less frequently. Viral concentration with centrifugation procedure indicated higher detection rates (21%, 95% CI: 10–33%) than other known sample concentration protocols. Generally, MPXV detection rates in wastewater samples strongly correlate with incidence cases of mpox (range of R = 0.78–0.94; p < 0.05). Findings from this study suggest that WBS of MPXV could be employed as an epidemiological early warning tool for disease monitoring and mpox outbreak prediction similar to the clinical case-based surveillance strategies. Full article

Leaders who lack leadership energy may struggle to demonstrate sustained competence and achieve effectiveness in difficult leadership situations. This research investigates the sources of leadership energy and examines the impact of leadership energy on the development and sustainability of leadership effectiveness and competence. This study employed a hypothetico-deductive research design, wherein the formulated hypotheses were tested through structural equation modelling (SEM). Data were collected using a questionnaire survey. A total of 272 responses were received from leaders of various industries, indicating a response rate of 66%. The findings of this study indicate that a leader’s capacity to respond to various situations, comprehend the importance of being directive, prioritize the development of positive attitudes and supportiveness, and recognize the significance of achievement are all factors that contribute to the internal mechanisms necessary for the leader’s manifestation of leadership energy. The study additionally discovered that leaders’ skills, qualities, and abilities are derived and maintained through their internal capacity and personal resilience emanating from their leadership energy. The hypotheses that were validated suggest a direct causal relationship, indicating that leadership motivation, leadership personality, and leadership orientation are significant factors in the generation of leadership energy. This study’s conclusions suggest that to sustain leadership competence and effectiveness, leaders must cultivate a culture that prioritizes both effectiveness and competence. The findings also imply that individuals must establish precise developmental objectives, as well as exhibit cognizance of and the acquisition of leadership expertise, knowledge and approaches. Thus, the need to reevaluate the competency-based approach to leadership is overwhelming. This study introduces the concept of leadership energy as a catalyst for perpetuating leadership effectiveness and competence. The study claims that the energy emanating from the intricate interplay of leaders’ orientation, experience, development, personality, and motivation engenders and perpetuates their efficacy and aptitude. Full article

Noroviruses constitute a significant aetiology of sporadic and epidemic gastroenteritis in human hosts worldwide, especially among young children, the elderly, and immunocompromised patients. The low infectious dose of the virus, protracted shedding in faeces, and the ability to persist in the environment promote viral transmission in different socioeconomic settings. Considering the substantial disease burden across healthcare and community settings and the difficulty in controlling the disease, we review aspects related to current knowledge about norovirus biology, mechanisms driving the evolutionary trends, epidemiology and molecular diversity, pathogenic mechanism, and immunity to viral infection. Additionally, we discuss the reservoir hosts, intra–inter host dynamics, and potential eco-evolutionary significance. Finally, we review norovirus vaccines in the development pipeline and further discuss the various host and pathogen factors that may complicate vaccine development. Full article

The solutions to the radial Schrödinger equation for a pseudoharmonic potential and Kratzer potential have been studied separately in the past. Despite different reports on the Kratzer potential, the fundamental theoretical quantities such as Fisher information have not been reported. In this study, we obtain the solution to the radial Schrödinger equation for the combination of the pseudoharmonic and Kratzer potentials in the presence of a constant-dependent potential, utilizing the concepts and formalism of the supersymmetric and shape invariance approach. The position expectation value and momentum expectation value are calculated employing the Hellmann–Feynman Theory. These expectation values are then used to calculate the Fisher information for both position and momentum spaces in both the absence and presence of the constant-dependent potential. The results obtained revealed that the presence of the constant-dependent potential leads to an increase in the energy eigenvalue, as well as in the position and momentum expectation values. Additionally, the constant-dependent potential increases the Fisher information for both position and momentum spaces. Furthermore, the product of the position expectation value and the momentum expectation value, along with the product of the Fisher information, satisfies both Fisher’s inequality and Cramer–Rao’s inequality. Full article

Population abundance and density estimates play important roles in biodiversity conservation assessment and can lead to prioritization of conservation efforts, strategies, and management. The Calabar angwantibo (Arctocebus calabarensis) is a poorly studied, Near-Threatened nocturnal, arboreal mammal species occurring only in the lowland moist tropical rainforest blocks of southeastern Nigeria and southwestern Cameroon. Like other arboreal nocturnal mammals, there are gaps in knowledge of the distribution and abundance of this species, which may be facing population declines due to habitat loss and hunting. In this study, we investigated the abundance and density of A. calabarensis in the Oban Hills Region of Nigeria. We conducted systematic distance sampling survey along 32 transects in different habitats in a 1227 km of survey efforts. A total of 41 sightings of A. calabarensis were detected, resulting in an abundance of 7345 individuals (95% CI = 1.51–4.37) with an estimated density of 2.57 animals/km². The estimated population abundance is 6515 individuals in closed-canopy forests and 830 individuals in secondary forests, with encounter rates of 0.52 individual/km² and 0.60 individuals/km² in the closed canopy and secondary forest habitats. The global estimates encounter rate of A. calabarensis across the habitat types is 0.33 individuals/km² and population abundance of 4456 individuals. Our findings indicate that the A. calabarensis populations can adapt to low changes in forest habitat modifications resulting from increasing and widespread forest disturbance by human-dominated activity, which is giving way to forest clearance for agriculture cultivation and infrastructural development. Our findings help to fill a knowledge gap regarding this species and may help establish a baseline for future management, population monitoring, and conservation of the cryptic population of A. calabarensis in Cross-Sanaga Forests. Full article

Agriculture plays a significant role in economic development and livelihood and is a key contributor to food security and nutrition. However, global concerns regarding the sustainability of the agricultural sector (mainly environmental damage) is linked to agricultural activities such as greenhouse gas (GHG) emissions, water pollution, and loss of biodiversity. The aim of this study was to assess the effectiveness of ORUN^® (a formulated agricultural chemical mixture) to reduce N₂O emissions from urine patches and to improve pasture yield, pasture N uptake, and soil mineral N concentrations. The field trials were conducted during the spring of 2015 on dairy urine patches at Massey University, New Zealand. Treatments consisted of control nil urine, control nil urine + ProGibb^®, urine only, urine + ProGibb^®, urine + ORUN^®, and urine + ORUN PLUS^® replicated four times in a randomized complete block design. At 31 days after treatment (DAT), analysis of soil samples in 0–5 cm soil profiles showed that urine + ProGibb^® significantly (p = 0.0041) increased the soil nitrate concentration (121.40 kgN/ha) compared with 48.15 kgN/ha from urine only. The urine + ProGib^® treatment produced significantly lower herbage N recovery (35% of applied N) compared with the urine only. Throughout the trial period, the urine patches treated with ProGibb^® and ORUN^® produced significantly higher N₂O fluxes compared with urine only and urine + ORUN PLUS^®, as well as higher surface soil nitrate and mineral N concentrations. Full article

Background and aim: Hepatocellular carcinoma (HCC) is a significant complication of hepatitis B and still poses a global public health concern. This systematic review and meta-analysis provide adequate details on the prevalence of HCC in the HBV population within Southeast Asian countries. Method: Following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) criteria, a thorough search for literature discussing the prevalence of HCC in the HBV population within southeast Asia was performed. Eligible studies were subjected to a meta-analysis utilising a DerSimonian and Laird approach and a random effect model. A protocol was registered with PROSPERO (CRD42023423953). Result: Our study meticulously recovered 41 articles from seven countries in Southeast Asia, namely Cambodia, Indonesia, Malaysia, the Philippines, Singapore, Thailand, and Vietnam. A total of 39,050 HBV patients and 7479 HCC cases in southeast Asia were analysed. The pooled prevalence of HCC in HBV cases within southeast Asia was 45.8% (95% CI, 34.3–57.8%, I² = 99.51%, p < 0.001). Singapore (62.5%, CI: 42.4–79.1) had the highest pooled prevalence of HCC in the HBV population compared to Vietnam, with the lowest estimate (22.4%, CI: 9.9–44.9). There was a drop in the pooled prevalence of HCC in HBV from 2016 until now (37.6%, CI: 19.2–60.5). Conclusion: The findings of this review reveal a high pooled prevalence of HCC in the HBV population and therefore stir the need for routine screening, management, and surveillance. Full article

Individuals and their leadership competencies have been the sole focus of project leadership research, rather than the project leadership’s behaviour and functions in project and organisational settings. As a result, this study investigates the project leadership functions and behaviours required for various project and organisational situations in order to propose a project leadership model that will be effective in all project and organisational situations. The model that was developed and tested in this study theorised about the project leadership function that project leaders are expected to perform as a result of their positions. It also described how project leaders could tailor their leadership functions and behaviours to address issues related to positions, organisational situations, and project situations. Three hypotheses were developed and tested using structural equation modelling to validate the model. The model’s perceptive power demonstrates adequate validity. The model’s validity implies that there are appropriate project leadership functions for different leadership levels and circumstances. The model’s validity also implies that each project leadership behaviour has its own value, as conditions and necessities dictate. The study assumes that a project leader can embrace project leadership by combining a few different project leadership functions and behaviours. Full article

Introduction: Klebsiella pneumoniae is a major pathogen implicated in healthcare-associated infections. Extended-spectrum β-lactamase (ESBL) and carbapenemase-producing K. pneumoniae isolates are a public health concern. This study investigated the existence of some ESBL and carbapenemase genes among clinical isolates of K. pneumoniae in Southwest Nigeria and additionally determined their circulating clones. Materials and Methods: Various clinical samples from 420 patients from seven tertiary hospitals within Southwestern Nigeria were processed between February 2018 and July 2019. These samples were cultured on blood agar and MacConkey agar, and the isolated bacteria were identified by Microbact GNB 12E. All K. pneumoniae were confirmed by polymerase chain reaction (PCR) using the 16s rRNA gene. Antibiotic susceptibility testing (AST) was done on these isolates, and the PCR was used to evaluate the common ESBL-encoding genes and carbapenem resistance genes. Genotyping was performed using multi-locus sequencing typing (MLST). Results: The overall prevalence of K. pneumoniae in Southwestern Nigeria was 30.5%. The AST revealed high resistance rates to tetracyclines (67.2%), oxacillin (61.7%), ampicillin (60.2%), ciprofloxacin (58.6%), chloramphenicol (56.3%), and lowest resistance to meropenem (43.0%). All isolates were susceptible to polymyxin B. The most prevalent ESBL gene was the TEM gene (47.7%), followed by CTX-M (43.8%), SHV (39.8%), OXA (27.3%), CTX-M-15 (19.5%), CTX-M-2 (11.1%), and CTX-M-9 (10.9%). Among the carbapenemase genes studied, the VIM gene (43.0%) was most detected, followed by OXA-48 (28.9%), IMP (22.7%), NDM (17.2%), KPC (13.3%), CMY (11.7%), and FOX (9.4%). GIM and SPM genes were not detected. MLST identified six different sequence types (STs) in this study. The most dominant ST was ST307 (50%, 5/10), while ST258, ST11, ST147, ST15, and ST321 had (10%, 1/10) each. Conclusion: High antimicrobial resistance in K. pneumoniae is a clear and present danger for managing infections in Nigeria. Additionally, the dominance of a successful international ST307 clone highlights the importance of ensuring that genomic surveillance remains a priority in the hospital environment in Nigeria. Full article

Per- and poly-fluoroalkyl substances (PFASs) are recalcitrant chemicals with stable carbon–fluorine (C–F) bonds. These complex substances are difficult to degrade; therefore, they persist in the environment, causing potential health effects on humans. This study focused on the photocatalytic degradation and defluorination of perfluorooctane sulfonate (PFOS) in aqueous water using TiO₂ nanoparticles under UV–visible light. The biosynthesized TiO₂ catalysts at pH 8, 10, and 12 were characterized using XRD, HRTEM, and HRSEM. The XRD patterns of the respective TiO₂ nanoparticles at different synthesized pHs exhibited similar anatase phases, and it was observed that the crystallite sizes decreased with increasing pH. The HRSEM and HRTEM confirmed the spherical shapes of the produced nanoparticles with particle size distributions of 12.17 nm, 10.65 nm, and 8.81 nm for the synthesized TiO₂ nanoparticles at pH 8, 10, and 12, respectively. The photodegradation and defluorination of PFOS were performed at various initial solution pH values of 2, 4, 6, 8, 10, and 12 under UV irradiation for 150 min. The study showed 95.62 and 56.13% degradation and defluorination efficiency at pH 2. The degradation and defluorination efficiencies significantly decreased as the pH of the solution increased; hence, the degradation increases at lower solution pHs. Without UV–visible light, the photocatalysis achieved a lower degradation and defluorination efficiency. The photocatalysis showed that the pH of the solution and UV irradiation greatly influence the degradation and defluorination. Therefore, TiO₂ nanoparticles were effective for the degradation and defluorination of PFOS under UV–visible light, which could also have an influence on the treatment of other PFASs in wastewater. Full article

This study aims to examine whether ready-mixed concrete (RMC) production in Nigeria is sustainable. This study proposes that RMC production will be sustainable, assuming the RMC plant, RMC products, plant management, RMC supply, RMC quality, and demand for RMC are sustainable. Based on a constructivist worldview, the proposition of RMC production’s sustainability was assessed by conducting a contextual analysis of five RMC plants in Lagos State, Nigeria. It was observed that the RMC plants required sustainability in power supply, plant output, and plant capacity. The plants have a sustainable supply of raw materials. The management methods and product control strategies were found to be unsustainable. Fair supply time, supply methods, and quality control systems were established in the findings. Challenges, such as administrative issues, economic problems, poor technology, and the absence of an innovative business model, influenced the sustainable demand for RMC products. This study concludes that alternative power supplies and methods such as just-in-time (JIT) purchasing systems and learning frameworks ought to be considered for RMC plants. Likewise, improving the ease of doing business would significantly help the sustainability of RMC production. This study presumes that RMC production is, as of now, not sustainable in Nigeria. Still, the sustainability of RMC production could be ensured through measures such as the reuse of waste, the adoption of innovative RMC production and delivery, and technological development. Full article