Scientific African最新文献

{"title":"Economic and geopolitical push factors, and migration tendencies in Nigeria: The intervening role of institutional quality","authors":"Ojo J. Adelakun ,&nbsp;Fatima A. Mohammed ,&nbsp;Abeeb O. Olaniran ,&nbsp;Taiwo H. Odugbemi","doi":"10.1016/j.sciaf.2025.e02955","DOIUrl":"10.1016/j.sciaf.2025.e02955","url":null,"abstract":"<div><div>This study examines how economic and geopolitical factors influence migration trends in Nigeria, given the increasing emigration of skilled professionals in critical sectors like healthcare and education. Utilizing a predictive analytical framework, we analyse the effects of Economic Policy Uncertainty (EPU) and Geopolitical Risk (GPR) indices on migration decisions. The findings indicate that both EPU and GPR are significant predictors of migration outflows, with economic uncertainty having a stronger impact than geopolitical risk. Furthermore, the study demonstrates that improved institutional quality reduces the migration-inducing effects of both risk factors. These results suggest that enhancement of governance and/or institutional reforms could help mitigate large-scale emigration and the resulting brain drain. The study provides evidence-based insights for policy interventions aimed at retaining skilled labour and addressing the root causes of mass emigration in Nigeria.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02955"},"PeriodicalIF":3.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of nitrogen and sulphur on manure decomposition in a savanna soil of Nigeria","authors":"B.O. Ukem,&nbsp;G.N. Essien,&nbsp;U.O. Peter,&nbsp;E.A. Samuel,&nbsp;A.S. Nicholas","doi":"10.1016/j.sciaf.2025.e02953","DOIUrl":"10.1016/j.sciaf.2025.e02953","url":null,"abstract":"<div><div>The rate of decomposition of manure and nutrients release pattern have been the concern of many workers. The ability of manure to provide essential plant nutrients depends on its quality. Due to variation in composition, availability of nutrients in manure is critical to its use in addressing soil fertility constraints. The objective of this study was to determine the effect of mineral N and S fertilizers on CO₂ evolution and nitrogen mineralization during manure incubation. Three rates of N and S (0, 60 and 120 kg N ha^-1; 0, 15 and 30 kg S ha^-1) and 0, 5 and 10 t ha^-1 manure (CD) were mixed with100 g of soil and incubated at 25 ⁰C and sampled weekly for CO₂ flux for six weeks. Ammonium- N and nitrate-N were determined at the end of the incubation. The amount of CO₂ flux increased in the first 2 wk of incubation where 10 t ha^-1 CD significantly increased CO₂ flux than half its rate. The interaction of 120 kg N ha^-1 x 0 kg S ha^-1 x 5 t ha^-1 CD had the highest amount of CO₂ flux (9.7 g kg ^-1) in wk 2. Ammonium-N increased significantly from the control (0.42 g kg ^-1) to 0.70 g kg ^-1 at 120 kg N ha ^-1 or 40 % difference, while nitrate-N was highest with 10 t ha ^-1 CD (0.25 g kg ^-1) compared to control (0.02 g kg ^-1) or 86 % difference. The decline in the amount of CO₂ flux in wk 6 revealed that the biodegradable carbon pool in the substrate decreased with time. Our findings suggest that mineral nitrogen fertilizer is required for manure decomposition whereas, mineral S fertilizer is not a major requirement for manure decomposition.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02953"},"PeriodicalIF":3.3,"publicationDate":"2025-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of agricultural diversification strategies and rural household food security in Malawi","authors":"Anderson Gondwe ,&nbsp;Lemekezani K. Chilora ,&nbsp;Levison Chiwaula ,&nbsp;Joseph Goeb","doi":"10.1016/j.sciaf.2025.e02952","DOIUrl":"10.1016/j.sciaf.2025.e02952","url":null,"abstract":"<div><div>While the potential benefits of diversification are widely recognised, evidence of the emergence of specific diversification strategies among farm households and their relationship with household welfare remains elusive. In this study, we addressed this gap by first identifying patterns in agricultural diversification among rural households in Malawi and defining the predominant agricultural diversification strategies used. Second, we analyse the extent to which household food security and total household farm income vary across particular agricultural diversification strategies. Third, the study identifies the diversification strategies or patterns that are the most important for income generation and enhancing household dietary diversity. Fourth, we assess the factors associated with household participation in specific agricultural diversification strategies. We employ the Malawi Rural Agricultural Livelihoods Panel Survey (MRALS) data and econometric techniques to address this objective. Our analysis reveals a growing trend in diversification, as evidenced by an increase in the share of households growing or keeping more than one type of crop or livestock between 2019 and 2024. Overall, the study finds that agricultural diversification is positively associated with household per capita income and household dietary diversity. Finally, the study suggests diversification strategies which policymakers should consider to enhance rural household welfare. We further suggest other factors which need to be considered when promoting these strategies.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02952"},"PeriodicalIF":3.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards measuring community resilience to flood risk: A baseline analysis","authors":"Lum Sonita Awah ,&nbsp;Johanes Amate Belle ,&nbsp;Israel Ropo Orimoloye ,&nbsp;Yong Sebastian Nyam","doi":"10.1016/j.sciaf.2025.e02948","DOIUrl":"10.1016/j.sciaf.2025.e02948","url":null,"abstract":"<div><div>Flooding, a major hazard exacerbated by climate change, rapid urbanisation, and poor land-use practices, continues to pose challenges for vulnerable coastal communities worldwide. This study offers a baseline assessment of flood resilience in ten communities within Limbe, Cameroon, using the Flood Resilience Measurement for Communities (FRMC) framework. Results show that all communities within the study area face annual flood events, with resilience scores between 25 and 39 (grade ‘C’). The research highlights strengths in education continuity and household preparedness, but also points out critical gaps in natural resources, social and financial investments in early warning systems, and infrastructure development. This pioneering use of the FRMC tool in Cameroon proves its effectiveness in resource-limited settings, offering practical insights for resilience enhancement. Recommended strategies include targeted financial investment, community-based preparedness efforts, leveraging natural capital through ecosystem restoration, and improved infrastructure planning, supporting global goals under SDG 11 for inclusive, safe, and resilient urbanisation. The study lays the groundwork for future resilience assessments and policy development, addressing the urgent need to strengthen adaptive capacities in flood-prone, rapidly urbanising coastal areas.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02948"},"PeriodicalIF":3.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance evaluation of a cylindrical-parabolic solar distillation unit for brackish water","authors":"Ahmed Ridha El Ouederni ,&nbsp;Mohamed Amine Ben Abdallah ,&nbsp;Mariem Zenkri ,&nbsp;Maha Ameur ,&nbsp;Yasmine El Ouederni ,&nbsp;Nour El Ouederni ,&nbsp;Aida Katar ,&nbsp;Rania Omrani","doi":"10.1016/j.sciaf.2025.e02935","DOIUrl":"10.1016/j.sciaf.2025.e02935","url":null,"abstract":"<div><div>Freshwater scarcity remains a worldwide challenge, and conventional desalination knowledges are frequently expensive and energy-intensive. Solar distillation with concentrator-based systems presents a supportable alternate, yet the consequence of inclination angle on the performance of cylindrical-parabolic concentrators (CPC) has been unsatisfactorily deliberate. This study addresses the need for efficient solar distillation systems by experimentally investigating the performance of a cylindrical-parabolic solar concentrator designed for brackish water desalination to evaluate a CPC solar desalination unit, focusing on thermal behavior and freshwater productivity under different inclination angles. The objective is to evaluate how variations in the inclination angle affect thermal behavior and freshwater yield. An outdoor experimental setup was developed to measure daily water production, temperature distribution, and system efficiency. The system demonstrated an average daily efficiency of approximately 44 %, with water production ranging from 1.9 to 3.3 liters per day, peaking at 1 pm. To better quantify productivity, two performance indicators the Instantaneous Production Factor (FPI) and the Cumulative Production Factor (FPC) were introduced to quantify thermal productivity and efficiency. Comparative analysis with similar solar distillation systems confirmed the effectiveness of the proposed design. The results highlight the potential of CPC-based systems for decentralized freshwater generation in water-scarce regions and emphasize the importance of optimizing inclination angle and thermal design for improved performance.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02935"},"PeriodicalIF":3.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145047610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The DUS-transformed generalized linear failure rate distribution: Properties, estimation, and applications","authors":"Mohammed Elgarhy ,&nbsp;Diaa S. Metwally ,&nbsp;Ibrahim E. Ragab ,&nbsp;Sule Omeiza Bashiru ,&nbsp;H.E. Semary ,&nbsp;Ahmed M. Gemeay","doi":"10.1016/j.sciaf.2025.e02891","DOIUrl":"10.1016/j.sciaf.2025.e02891","url":null,"abstract":"<div><div>Probability distributions are fundamental tools in statistics, enabling the modeling and analysis of random phenomena across diverse fields such as engineering, medicine, finance, and environmental science. However, classical distributions often exhibit limitations in capturing the complexity of real-world data. This study addresses these limitations by introducing the DUS-transformed generalized linear failure rate (DUS-GLF) distribution, a novel extension of the generalized linear failure rate (GLF) distribution using the DUS transformation technique. The DUS-GLF distribution enhances the flexibility of the GLF model, enabling it to accommodate a wider range of data behaviors. Key statistical properties of the DUS-GLF distribution, such as its hazard rate function, moments, incomplete moments, entropy, and extropy, are derived. Sixteen estimation methods are employed to estimate the parameters of the DUS-GLF distribution, ensuring its practical applicability. The performance of the DUS-GLF distribution is evaluated using two real-world datasets, demonstrating its superior goodness-of-fit and predictive accuracy compared to other competing models. This research provides a robust statistical tool for complex data modeling, enhancing both theoretical and applied statistical analysis.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"29 ","pages":"Article e02891"},"PeriodicalIF":3.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144988331","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bridging the treatment gap: Modelling the impact of ART access for immigrants on HIV/AIDS transmission in Botswana","authors":"Refilwe Matlou ,&nbsp;Tefa Kaisara ,&nbsp;Farai Nyabadza","doi":"10.1016/j.sciaf.2025.e02914","DOIUrl":"10.1016/j.sciaf.2025.e02914","url":null,"abstract":"<div><div>The Human Immunodeficiency virus (HIV) remains a major public health concern in Botswana, with significant strides made in treatment coverage among citizens. However, for many years, the immigrant population (which comprised about 7% of the population in 2016) was excluded from accessing antiretroviral therapy (ART), raising concerns about their role in sustaining HIV transmission. This study formulates and analyses a deterministic compartmental model that incorporates both citizens and immigrants, stratifying infected individuals by treatment and viral suppression status. The model includes key features such as ART adherence, viral suppression dynamics, and Acquired Immunodeficiency Syndrome (AIDS) progression. A core component of the model is the introduction of a policy intervention that grants ART access to immigrants, as implemented by the Botswana government in 2019. The model steady states are determined and analysed in terms of the basic reproduction number, <span><math><mrow><mo>(</mo><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>p</mi><mi>r</mi><mi>e</mi></mrow></msubsup><mo>)</mo></mrow></math></span>. It is observed that the model has two unique steady states, the disease-free steady state and an endemic equilibrium point. The disease-free equilibrium point is globally asymptotically stable if <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>p</mi><mi>r</mi><mi>e</mi></mrow></msubsup><mo>&lt;</mo><mn>1</mn></mrow></math></span>, while the endemic equilibrium point is globally asymptotically stable if <span><math><mrow><msubsup><mrow><mi>R</mi></mrow><mrow><mn>0</mn></mrow><mrow><mi>p</mi><mi>r</mi><mi>e</mi></mrow></msubsup><mo>&gt;</mo><mn>1</mn></mrow></math></span>. Comparing pre-policy and post-policy scenarios, we find that the reproduction number is significantly higher before the policy change, indicating that excluding immigrants from treatment increases overall HIV transmission. Numerical simulations are carried out to determine the impact of the immigrant population on the incidence of HIV/AIDS dynamics. Our results suggest that extending ART access to immigrants significantly reduces the overall HIV burden and can accelerate progress towards epidemic control.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"30 ","pages":"Article e02914"},"PeriodicalIF":3.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145097533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing groundwater potential in the western High Atlas (Morocco): An integrated approach based on remote sensing, GIS techniques, frequency ratio, and Shannon entropy","authors":"Abdelaziz Harroud ,&nbsp;Latifa Ait Dhmane ,&nbsp;Khalid Benjmel ,&nbsp;Jalal Moustadraf ,&nbsp;Khalid Mehdi ,&nbsp;Issam Mehdi ,&nbsp;Fouad Amraoui ,&nbsp;Zourarah Bendahhou","doi":"10.1016/j.sciaf.2025.e02930","DOIUrl":"10.1016/j.sciaf.2025.e02930","url":null,"abstract":"<div><div>This study aims to map groundwater potential zones in the mountainous and fractured region of Amizmiz, which is characterized by a semi-arid climate. The combined effects of climate change, increasing aridity, and geological complexity place growing pressure on groundwater resources, making their sustainable management a critical challenge. To address this issue, a multi-criteria methodology was developed by integrating fifteen geological, topographic, climatic, and hydrological factors to optimize drilling site selection and enhance the chances of locating productive aquifers. Two statistical modeling approaches, Shannon’s Entropy (SE) and Frequency Ratio (FR), were applied. A spatial database was constructed using remote sensing and Geographic Information System (GIS) techniques, incorporating data from 150 water points along with relevant groundwater-controlling factors. The dataset was divided into 70 % for model training and 30 % for validation. Two groundwater potential maps were produced and classified into five potential levels. Results indicate that zones identified as having high potential correspond closely with most productive water points. The SE model (Rate Success = 0.86) showed smoother spatial continuity, while the FR model (Rate Success = 0.88) effectively highlighted several favorable zones, albeit with sharper spatial transitions. To reinforce validation, an apparent electrical resistivity map was used, revealing a significant concordance between conductive zones and areas of high groundwater potential: 85 % for the FR model and 89 % for the SE model. These findings confirm the reliability of the generated maps for guiding future drilling. Future studies should integrate hydro-dynamic parameters and explore machine learning techniques to further enhance prediction accuracy.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"29 ","pages":"Article e02930"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144924914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimated cost and operational structure of pgSIT malaria vector control programs in selected West African countries.","authors":"William A C Gendron, Robyn Raban, Agastya Mondal, Héctor M Sánchez C, David Zilberman, Patrick G C Ilboudo, Umberto D'Alessandro, John M Marshall, Omar S Akbari","doi":"10.1016/j.sciaf.2025.e02888","DOIUrl":"10.1016/j.sciaf.2025.e02888","url":null,"abstract":"<p><p>Malaria control has primarily been achieved through vector control, but current methods are insufficient to achieve elimination. Precision guided sterile insect technique (pgSIT) is a mosquito suppression technique that generates sterile male mosquitoes for mass release. Our previous studies showed that this intervention is expected to be highly cost-effective in a malaria endemic region of West Africa, but these estimates used only 15-31% capacity for sex sorting, which is the limiting production step and a primary cost. We, therefore, determined the most cost efficient facility size by calculating the cost per million <i>Anopheles gambiae</i> suppressed as the facility was scaled up to suppress more mosquitoes. We developed an optimized facility size per 9.2 million mosquitoes suppressed, which can be a framework for scaling and increases the cost effectiveness of this intervention. The development of this intervention can potentially interrupt malaria transmission, strengthen local public health institutions, create manufacturing capacity, provide local jobs, and enhance regional health security capabilities that are more resilient to disruptions in supply chains and malaria investment.</p>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"29 ","pages":"None"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12463680/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145186811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimal control analysis of malaria and its associated complications","authors":"Bereket Hido Wako ,&nbsp;Mohammed Yiha Dawed ,&nbsp;Legesse Lemecha Obsu","doi":"10.1016/j.sciaf.2025.e02932","DOIUrl":"10.1016/j.sciaf.2025.e02932","url":null,"abstract":"<div><div>Malaria is an infectious disease caused by a <em>Plasmodium</em> parasite. It remains one of the most life-threatening vector-borne diseases worldwide. The disease burden is further exacerbated by life-threatening complications which poses a significant challenge to healthcare systems, where treatment capacity is often saturated. This study advances previous malaria modelling research by explicitly incorporating malaria-induced complications into an optimal control framework with a realistic saturated treatment function that captures healthcare resource limitations. It specifically addresses the problem of designing cost-effective intervention strategies that minimise both the number of infections and the associated complications under resource constraints. To solve this, we applied stability and bifurcation analyses to establish threshold conditions for disease persistence. The study then extended the model into an optimal control framework using Pontryagin’s minimum principle. The results show that saturated treatment significantly reduces recovery. Numerical simulations demonstrate the time-dependent control strategies significantly influence malaria dynamics across different parameter scenarios. Effectiveness analysis indicates that simultaneous implementation of multiple control measures is the most efficient strategy to reduce the malaria burden. Prioritising outpatient treatment combined with insecticide spraying provides an economically viable approach, particularly in resource-limited settings.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"29 ","pages":"Article e02932"},"PeriodicalIF":3.3,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144932227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}