Scientific African最新文献

{"title":"Antidepressant-like effect of picralima nitida total crude alkaloidal fraction in mice","authors":"Prince Dagadu Okyere ,&nbsp;Christian Chukwuma Ndu ,&nbsp;Donatus Wewura Adongo ,&nbsp;Charles Kwaku Benneh ,&nbsp;Eric Woode ,&nbsp;Edmund Ekuadzi ,&nbsp;Wonder Kofi Mensah Abotsi ,&nbsp;Eric Boakye-Gyasi ,&nbsp;Priscilla Kolibea Mante","doi":"10.1016/j.sciaf.2025.e02548","DOIUrl":"10.1016/j.sciaf.2025.e02548","url":null,"abstract":"<div><div>In 2019, WHO, reported that an estimate of 350 million people globally have depression. Despite the advances made in current pharmacotherapy, about 30–40 % of patients receive insufficient treatment because of the increased occurrence of partial or non-response as well as delayed onset of antidepressive action. Herbs, however, offer a vital solution to potential pharmacological agents for effective depression management. Our study investigated the potential antidepressant-like action of <em>Picralima nitida</em> total crude alkaloidal fraction in mice.</div><div>Crude total alkaloidal extract from <em>P. nitida</em> (PNE) was obtained by cold macerating dried, powdered seeds in petroleum ether for 48 h, liberating total alkaloids with 6 % acetic acid, precipitating total alkaloid with concentrated ammonia, and dissolving precipitate in chloroform. The potential antidepressant-like action of PNE was studied in the Forced Swim Test (FST) and Tail suspension test (TST) in mice (<em>n</em> = 8), together with a study of the potential influence of noradrenergic and serotonin pathways.</div><div>PNE significantly reduced immobility times in mice in the FST (<em>F_8, ₄₂ = 15.74, P</em> &lt; 0.0001) and TST (<em>F_7, ₄₆ = 22.79, P</em> &lt; 0.0001). Pretreatment with reserpine, a vesicular monoamine transporter inhibitor, which depletes monoamines reversed the initial reduction in immobility time of mice administered PNE in TST and FST. PNE did not significantly increase 5-HTP induced head-twitches, but it potentiated noradrenaline toxicity. PNE at 300 mg/kg resulted in 60 % probability of survival while PNE at 30 and 100 mg/kg resulted in 80 % probability of survival over 48 h Antidepressant-like effects of PNE, at all doses, were reversed by AMPT pretreatment.</div><div>This study found that PNE has antidepressant-like effect, predominantly due to effects on noradrenergic neurotransmission, offering a new perspective mechanisms of its pharmacological activity. These findings highlight the plant's potential as a source for developing novel, accessible and culturally relevant antidepressant drugs particularly in regions like sub-Saharan Africa.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02548"},"PeriodicalIF":2.7,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098056","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":"Puma algorithm for environmental emissions and generation costs minimization dispatch in power systems","authors":"Badr Al Faiya ,&nbsp;Ghareeb Moustafa ,&nbsp;Hashim Alnami ,&nbsp;Ahmed R. Ginidi ,&nbsp;Abdullah M. Shaheen","doi":"10.1016/j.sciaf.2025.e02547","DOIUrl":"10.1016/j.sciaf.2025.e02547","url":null,"abstract":"<div><div>Optimizing power systems is a crucial task nowadays for cost-effective operations that ensure profitability for providers and affordability for consumers. Also, efforts are directed toward harmonizing economic objectives with environmental conservation through accurate modelling of the Economic and Environmental Dispatch (EED) problem. This study adopts a more complex approach by formulating the fuel cost and produced emission objectives as cubic polynomial functions. Also, this paper proposes a novel Puma Optimization Operator (POO), inspired by the hunting behavior of pumas for the optimal allocation of power generation across various units, considering both economic and environmental factors. It efficiently navigates the solution space by balancing exploration and exploitation, leveraging puma-like intelligence to minimize both fuel costs and greenhouse gas emissions, including CO2, NOx, and SO2. The POO algorithm is tested on the IEEE 30-bus power system with six thermal units, delivering superior performance compared to advanced optimization algorithms such as the Osprey Optimization Algorithm (OOA), Aquila Optimizer (AO), Slim Mould Algorithm (SMA), Artificial Rabbit Optimization (ARO), and Coati optimization technique. The POO algorithm consistently outperforms other algorithms in minimizing both generation and emission costs across all loading levels, with improvement percentages ranging from approximately 1.221 % to 1.6 % compared to OOA, 0.59 % to 0.86 % compared to AO, 2.47 % to 3.42 % compared to SMA, 0.89 % to 1.67 % compared to Coati and 0.03 % to 0.13 % compared to ARO. Moreover, statistical analysis underscores POO's superior performance compared to other optimizers, establishing it as a highly competitive option concerning both cost and emissions. Also, the study is extended to address the dynamic ED problem, incorporating a 24 h load demand profile and ramp-rate constraints for power generation units. The proposed POO dynamically adjusts the power outputs of generators to meet hourly demand while adhering to operational limits. The results demonstrate that the proposed approach ensures smooth transitions in generator outputs, respects dynamic operational constraints, and achieves a realistic balance between cost efficiency and environmental impact.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02547"},"PeriodicalIF":2.7,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148864","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":"How do rural industrial sites impact migrant motives and the socio-economic conditions of local and migrant populations?","authors":"Itohan-Osa Abu ,&nbsp;Michael Thiel ,&nbsp;Clement Nyamekye ,&nbsp;Yaw Mensah Asare ,&nbsp;Emmanuel Agyapong ,&nbsp;Benjamin Agbemor ,&nbsp;Ebenezer N.K. Boateng ,&nbsp;Chibuike Ibebuchi ,&nbsp;Tobias Ullmann ,&nbsp;Jürgen Rauh ,&nbsp;Hannes Taubenböck","doi":"10.1016/j.sciaf.2025.e02546","DOIUrl":"10.1016/j.sciaf.2025.e02546","url":null,"abstract":"<div><div>Understanding the impact of rural industrialization on migration motives and the socio-economic well-being of local and migrant populations is critical for developing policies that aim at improving living standards and ensuring inclusive economic growth. Previous studies have emphasized rural-to-urban migration in Ghana, this study investigates the socio-economic impacts of rural industrial sites on local and migrant populations, drawing on a comprehensive survey conducted across various villages in Ghana, West Africa. We examine the pull effects of rural industrial sites as sources of economic growth and social transformation. Through a detailed questionnaire survey leveraging mobile technology, the research captures responses from 1,102 respondents, comprising both Indigenous people and migrants, to understand the complex socio-economic dynamics at play. Our findings show that among other factors, migration patterns are principally influenced by socio-economic motives, with significant gender differences in both motivations and outcomes. The logistic regression analysis indicates that men are more likely to migrate for socio-economic reasons compared to women, with an odds ratio (OR) of 1.50, which is statistically significant at a 95 % confidence level. On the other hand, women are more likely to migrate for family reunification. Furthermore, individuals with earnings above the minimum wage prior to migrating were significantly more likely to migrate, with a statistically significant OR of 2.82, suggesting that higher initial earnings might ease the migration process, and it is not always not the poorest people that migrate. Additionally, migrants citing socio-economic reasons for moving to the rural industrial sites are significantly more likely to achieve satisfactory outcomes, with a statistically significant OR of 5.12. Our results show that though migrant experiences may vary, industrial sites in rural communities boost local employment and economic activities. These findings emphasize the critical role of economic success, information access, and demographic factors in shaping migration experiences and outcomes, offering valuable insights for cross-national labour migration and policy development.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02546"},"PeriodicalIF":2.7,"publicationDate":"2025-01-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148861","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":"Environmental DNA metabarcoding reveals the presence of invasive and cryptic species in the Mweru-Luapula fishery","authors":"Bornwell Seemani ,&nbsp;Carel Oosthuizen ,&nbsp;Cyprian Katongo ,&nbsp;Arrie Klopper ,&nbsp;Paulette Bloomer","doi":"10.1016/j.sciaf.2025.e02544","DOIUrl":"10.1016/j.sciaf.2025.e02544","url":null,"abstract":"<div><div>Environmental DNA (eDNA) has in recent years emerged as a major approach to complement traditional sampling methods across aquatic freshwater systems. Despite this increasing application of eDNA metabarcoding approach, a number of developing countries have not yet fully incorporated the tool in the management and monitoring of aquatic biodiversity. This study aimed at analysing eDNA water samples collected for the first time across 18 sampling sites of the Mweru-Luapula (ML) fishery to determine the presence and distribution of invasive and native freshwater fishes. The study further applied Simpson diversity indices (SDIs) to investigate the diversity of species between invaded and non-invaded systems. Environmental DNA analysis revealed the presence of invasive <em>Parachanna</em> species in three of the four strata of the fishery, compared to only two strata previously known to have been invaded when assessed by traditional methods. In addition, five rare species (<em>Marcusenius senegalensis, Trachurus japonicus, Labeo nasus, Campylomormyrus compressirostris and Synodontis schoutedeni</em>) were also initially detected using eDNA. Low SDI values were recorded in invaded individual sampling sites. The coefficient association between read counts and species frequencies (<em>r</em> = 0.31; <em>p</em>-value = 0.239) and diversity indices (<em>r</em> = 0.1; <em>p</em>-value = 0.717) did not have any significant impact. This study has provided a platform for further investigations on the presence and impact of invasive species in other fishery areas across the country, using eDNA water samples collected at different water depths to update the species inventories. The revelation of unexpected species for the first time in the fishery and detection of invasive <em>Parachanna</em> species in multiple sites has demonstrated the need for introducing eDNA metabarcoding alongside conventional methods to monitor alien invasive species and thus effectively manage and conserve the threatened aquatic biodiversity of the freshwater ML fishery of Zambia.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02544"},"PeriodicalIF":2.7,"publicationDate":"2025-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143097856","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":"Unlocking chemical markers for the standardization of antimalarial medicinal plants and products: Application of the herbal marker ranking system (Herb MaRS)","authors":"John Nii Addotey ,&nbsp;Priscilla Boadu ,&nbsp;Emmanuel Quaye Kontoh ,&nbsp;Flavia Owusu Yeboah ,&nbsp;Felix Kaiser ,&nbsp;Francis Ackah Armah ,&nbsp;Rita Akosua Dickson ,&nbsp;Isaac Kingsley Amponsah","doi":"10.1016/j.sciaf.2025.e02538","DOIUrl":"10.1016/j.sciaf.2025.e02538","url":null,"abstract":"<div><div>Herbal products lack standardization due to complex and variable phytochemical constituents. An approach to solving this the use of chemical markers to control quality and effectiveness. This study aimed at developing phytochemical standards for antimalaria herbal products documented in the Recommended Essential Herbal Medicines List of Ghana using the herbal marker ranking system (Herb MaRS). The products were reviewed, the frequently used raw materials were selected, and their evidence of safety and efficacy documented. Selecting bioactive compounds from the plants as potential markers were based on the Herb MaRS criteria. Compounds with of antimalarial activity scored 2 or 0 (not active); evidence of managing a symptom (1 or 0); concentration of the compound in the plant, &lt;5µg/g, scored 1 point (too low), 2 points (5–50µg/g), or 3 points (&gt;50 µg/g). Reference standards available (score 1), analytical method available (1 point). A toxic compound scored all 8 points. Compounds that scored 8 were considered as most suitable markers with those scoring 4 as appreciably suitable. All those scoring less than 3 were not considered. The selected markers include cryptolepine (in <em>Cryptolepis sanguinolenta</em>), echitamine, <em>β</em>-amyrin, boonein, loganin, and lupeol (in <em>Alstonia boonei</em>), azadirachtin, nimbolide, nimbin, and salanin (in <em>Azadirachta indica</em>), lucidin, alizarin, damnacanthal, Rubiadin and purpuroxanthin (in <em>Morinda lucida</em>), quercetin, caffeic acid, and quinovic acid (in <em>Nauclea latifolia</em>). The selected markers are the ideal compounds for the standardisation of antimalaria herbal products containing these plant materials. Herb MaRS criteria could be used to select chemical markers for herbal material quality control.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02538"},"PeriodicalIF":2.7,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098017","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":"Managing climate change through social justice in Africa: Key lessons from the Libode area of Eastern Cape, South Africa","authors":"Amos Apraku ,&nbsp;Benjamin Apraku Gyampoh ,&nbsp;John F. Morton ,&nbsp;Simon Mariwah","doi":"10.1016/j.sciaf.2025.e02534","DOIUrl":"10.1016/j.sciaf.2025.e02534","url":null,"abstract":"<div><div>Climate change is considered as one of the greatest challenges to humanity, with Africa seen as one of the most affected continents due to low resilience and adaptive capacities. The complex interaction between multiple socio-ecological and economic stressors pose a great challenge to the application of the concept of social justice and its associated principles in managing climate change in Africa. Based on empirical research with 150 respondents and interactions in Libode, this paper highlights that water, food and settlement insecurities, floods, crop and animal losses and water-borne diseases remain some of the key negative impacts of climate change to rural residents in the Eastern Cape Province. Despite these adverse effects, the application of the core principles embedded in social justice as a tool for managing climate change impacts in the study area is elusive due to inadequate socio-economic and natural adjustments in response to actual and/or expected climate change adverse effects. The paper concludes that various forms of socio-economic and environmental inequalities can be reduced to the barest minimum and increase social transformation drastically in the Eastern Cape through the application of the principles of social justice to enhance adaptive capabilities.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02534"},"PeriodicalIF":2.7,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148860","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":"Livelihood vulnerability to climate change in Makueni County, Kenya","authors":"Virginia Kavuu Muia ,&nbsp;Alfred Owuor Opere ,&nbsp;Dorothy Akinyi Amwata","doi":"10.1016/j.sciaf.2025.e02530","DOIUrl":"10.1016/j.sciaf.2025.e02530","url":null,"abstract":"<div><div>Although Kenya's arid and semi-arid regions are extremely vulnerable to the effects of climate change, very few studies have examined this vulnerability in depth. This study sought to assess livelihood vulnerability to climate change in Makueni County, an arid and semi-arid region in Kenya's east. The study applied the Livelihood Vulnerability Index (LVI) and the Intergovernmental Panel for Climate Change (LVI-IPCC) framework to assess livelihood vulnerability to climate change in Makueni County, Kenya. Semi-structured questionnaires were used to collect cross-sectional primary data from a population sample of 400 household heads. Data on temperature and precipitation was obtained from the Kenya Meteorological Department. The findings of the study indicate that Makueni County is highly vulnerable to the effects of climate change (LVI = 0.305, LVI-IPCC = 0.036). Vulnerability in the county was majorly influenced by four main factors namely: water (vulnerability score: 0.375); natural disasters and climate variability (vulnerability score:0.368); livelihood strategies (vulnerability score:0.363); and food (vulnerability score: 0.331). When vulnerability for the sub counties were computed and compared, Kibwezi and Makindu sub counties were the most vulnerable (0.305 and 0.295, respectively) under the LVI approach while Makindu and Nzaui sub counties (0.035 and 0.032 respectively) were the most vulnerable under the LVI-IPCC approach. According to the Kruskal-Wallis H test, vulnerability was similar across the nine sub counties in Makueni county (p 0.05). These results serve as empirical evidence to guide the choice and implementation of future courses of action to reduce the risks associated with climate change. They provide a valuable basis for designing appropriate interventions and guiding policy decisions that address the specific vulnerabilities that households in the county confront. In particular, policymakers and actors at all levels of government (national county and sub-county) need to devise and implement context-specific strategies to improve water availability and food production. Furthermore, households need to diversify their livelihoods beyond farming in order to reduce climate-related losses. There is also a need for a robust early warning system for climate hazards to enable farmers prepare adequately for climate shocks.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02530"},"PeriodicalIF":2.7,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098409","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":"Ethnobotanical study of traditional medicinal plants used by the Sidama people to treat human ailments in the Bensa district of Sidama region, Ethiopia","authors":"Tegenu Mekuria ,&nbsp;Juhar Zemede ,&nbsp;Belay Melese ,&nbsp;Guang-Wan Hu","doi":"10.1016/j.sciaf.2025.e02541","DOIUrl":"10.1016/j.sciaf.2025.e02541","url":null,"abstract":"<div><h3>Background</h3><div>Traditional medicinal plants are integral to Ethiopia's primary healthcare system. The Sidama people have a profound spiritual connection to sacred forests and traditional medicines. However, despite preserving a diverse range of indigenous traditional medicinal plants, the traditional knowledge in treating human ailments in the Bensa district has not yet been ethnobotanically explored. This study aims to document and analyze the use of medicinal plants in managing human ailments and the associated knowledge used by the Sidama people of the Bensa district.</div></div><div><h3>Methods</h3><div>The ethnobotanical data was collected from 84 informants through semi-structured interviews and group discussions and 90 informants through focus group discussions. The data were analyzed using descriptive statistics, use reports (UR), informant consensus factor (IFC), and fidelity level (FL). Medicinal plant specimens were collected and deposited at the herbarium of the Ethiopia Biodiversity Institute and Shashemene Botanical Garden.</div></div><div><h3>Results</h3><div>A total of 214 species of medicinal plants belonging to 80 families and 182 genera were documented. Asteraceae and Lamiaceae contribute the highest number of species. <em>Leucas martinicensis</em> (Jacq.) R. Br. (UR, 41), <em>Bersama abyssinica</em> Fresen. (UR, 40), and <em>Asparagus africanus</em> Lam (UR, 38) were the most popular species used by local people, with the highest healing potential of medicinal plants. The cancer disease category had the highest consensus value (0.90), and two species, <em>Zanthoxylum chalybeum</em> Engl and <em>Asparagus africanus</em>, were identified as most effective in treating cancer-related ailments. The study also revealed novel uses of certain endemic medicinal plants such as <em>Acanthus senni</em> Chiov, <em>Bothriocline schimperi</em> Oliv. &amp; Hiern ex Benth, <em>Rosa abyssinica</em> Hochst, <em>Rhus glutinosa</em> . ex A. Rich., and <em>Vepris dainellii</em> (Pic.Serm.) Kokwaro in managing specific ailments for the first time.</div></div><div><h3>Conclusions</h3><div>The Sidama people have a rich history of preparation and application of diverse plants for ethnomedicinal purposes. However, the existence of ethnomedicinal resources is threatened by agricultural expansion, urbanization, and firewood collection. Therefore, in-situ and ex-situ conservation of medicinal plants are crucial for their future utilization. In addition, more substantial formal support for the existing culture-based protection and management of sacred forests is required to safeguard medicinal plants in the Sidama region. The medicinal efficacy of the studied plants raises awareness of the conservation of valuable plants implicated in treating diverse ailments.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02541"},"PeriodicalIF":2.7,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098053","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":"Prediction of future climate variability and its implications for rainfed agriculture in the Guder watershed, Ethiopia","authors":"Daniel Assefa Tofu","doi":"10.1016/j.sciaf.2025.e02531","DOIUrl":"10.1016/j.sciaf.2025.e02531","url":null,"abstract":"<div><div>This study aims to predict the future changes in mean monthly temperature and rainfall over the Guder watershed during the early (2011–2039), middle (2041–2069), and end (2071–2099) of the century under the Representative Concentration Pathways (RCPs) scenarios. A statistical downscaling procedure was used to downscale the results of the CanESM2 model. Observed temperature and rainfall data were used to downscale the future climate from ensembles of 20 GCMs of the CMIP5-CanESM2 model for three RCP scenarios, namely RCP2.6, RCP4.5 and RCP8.5. The results showed that mean annual and seasonal rainfall will increase throughout the watershed with high variability across both the RCPs and the study periods. Regardless of the projection period, the minimum temperature is expected to increase by 0.06 °C (RCP2.6), 0.09 °C (RCP4.5) and 0.11 °C (RCP8.5) by 2099. Similarly, the average monthly maximum temperature for 2011–2099 showed persistent warming between 0.96 °C and 1.02 °C under RCP2.6, 0.02 °C and 0.42 °C under RCP4.5, and 0.05 °C and 0.96 °C under RCP8.5 compared to the baseline period. Accordingly, the cumulative impacts of projected rainfall and temperatures in the catchment are expected to be negative. Therefore, policymakers and local planners can use this study to strengthen the preparedness of smallholder farmers' through promoting adaptation strategies such as installing early warning systems (particularly, by making existing early warning system functional), constructing soil and water conservation measures, and raising awareness to diversify their income sources to mitigate possible impacts of extreme events (e.g. heat stress, uncertain torrential rainfall, drought and floods) and build resilient livelihoods. Above all, collaboration between rural people and local planners is highly demanded for effective promotion and implementation of innovative measures (improved seed &amp; in organic chemicals), soil and water conservation activities (e.g., tracing, tree planting, mulching, conservation tillage) and early warning information for possible impacts of climate and build resilient livelihoods.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02531"},"PeriodicalIF":2.7,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098013","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":"Optimization of Stirling generator for the production of electric energy using non-aggregate methods","authors":"Victor Zogbochi ,&nbsp;Patrice Koffi Chetangny ,&nbsp;Mawuena Medewou ,&nbsp;Sossou Houndedako ,&nbsp;Gerald Barbier ,&nbsp;Didier Chamagne","doi":"10.1016/j.sciaf.2025.e02540","DOIUrl":"10.1016/j.sciaf.2025.e02540","url":null,"abstract":"<div><div>The electrification policy adopted by many countries called “off-grid electrification”, consists of producing electrical energy where it is consumed from renewable sources. Among the methods of converting thermal energy into electricity, hot air engines (Stirling type) occupy a dominant place because they find their applications both in the renewable energy sector and in the recovery of waste heat. The aim of this work is to develop an optimal model of a generator consisting of a Stirling engine and an axial flux permanent magnet generator which will be easily displaceable and adapted to all hot primary sources. The β type Stirling engine is considered in this research. The objective is to design a compact mobile machine, accessible to households and capable of producing a minimum electric power of 2 kW under a temperature difference ∆<em>T</em> ≤ 1000 ° K. The artificial Bee Swarm Optimization Algorithm is used to determine the optimal mechanical power of the Stirling engine. This power constitutes the input variable of the generator model to determine the electrical power and the overall efficiency of the generator set. The results proved that for a temperature difference (∆T) of 600°K between the hot and cold heads, we obtain an electrical power of 4 kW corresponding to an overall efficiency of 31 %. The effect of hot head temperature variation and cylinder volume ratio where also considered for the global performance of the generator.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"27 ","pages":"Article e02540"},"PeriodicalIF":2.7,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098075","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}