Scientific African最新文献

Effects of timeliness and quality of tractor-hire services on smallholder farmers’ technical, allocative, and economic efficiencies: Evidence from Botswana 拖拉机租赁服务的及时性和质量对小农技术、配置和经济效率的影响：来自博茨瓦纳的证据

IF 2.7

Scientific African Pub Date : 2025-05-11 DOI: 10.1016/j.sciaf.2025.e02744

Tebogo Mokumako , Samuel Kwesi Ndzebah Dadzie , Henry Nana De-Graft Acquah , Alexander Tetteh Kwasi Nuer , Emmanuel Wisgtos Inkoom , Michael Robert Nkuba

{"title":"Effects of timeliness and quality of tractor-hire services on smallholder farmers’ technical, allocative, and economic efficiencies: Evidence from Botswana","authors":"Tebogo Mokumako , Samuel Kwesi Ndzebah Dadzie , Henry Nana De-Graft Acquah , Alexander Tetteh Kwasi Nuer , Emmanuel Wisgtos Inkoom , Michael Robert Nkuba","doi":"10.1016/j.sciaf.2025.e02744","DOIUrl":"10.1016/j.sciaf.2025.e02744","url":null,"abstract":"<div><div>Smallholder farmers contribute to aggregate food production. However, their yields are low in Botswana, despite government subsidies for tractor-hire services and seeds to improve productivity and food security. In semi-arid areas, the onset of rains is variable, making access to inputs around the onset of rains critical for smallholders’ crop productivity. The study aimed to assess the effects of farmers’ timely access to tractor services on their efficiency. This study examined smallholder arable crop farmers’ technical, allocative, and economic efficiencies. The household survey gathered data on farmer characteristics, socio-economic, and production. Data was collected from 470 smallholder arable crop farmers in Central District, Botswana. The Stochastic Frontier Approach (SFA) was used to analyze the efficiencies, and the Tobit regressions were used to determine the factors influencing the efficiencies. The results show that poor quality and delays in farmers’ access to tractor-hire services negatively affect technical and economic efficiencies. Smallholders had a mean technical efficiency score of 44 %, an allocative efficiency score of 6.6 %, and an economic efficiency score of 2.9 %. The input subsidy program positively influences farmers’ productivity. Agricultural input policies should take serious consideration of quality and timeliness of smallholders’ access to inputs and services in a bid to increase their production efficiencies.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02744"},"PeriodicalIF":2.7,"publicationDate":"2025-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931835","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}

引用次数: 0

A new flexible generalized family for generating continuous models 一种新的用于生成连续模型的柔性广义族

IF 2.7

Scientific African Pub Date : 2025-05-10 DOI: 10.1016/j.sciaf.2025.e02723

Regent Retrospect Musekwa, Boikanyo Makubate

引用次数: 0

Transient stability improvement of a DFIG-based network-connected wind power plant by control of the flux neutralization current during the voltage drop 通过控制电压降期间的磁链中和电流改善dfig型并网风电场的暂态稳定性

IF 2.7

Scientific African Pub Date : 2025-05-10 DOI: 10.1016/j.sciaf.2025.e02745

Azeddine Loulijat , Abdelilah Hilali , Mohamed Makhad , Hamid Chojaa , Said Mahfoud , Mishari Metab Almalki , Almoataz Y. Abdelaziz , Mahmoud A. Mossa

{"title":"Transient stability improvement of a DFIG-based network-connected wind power plant by control of the flux neutralization current during the voltage drop","authors":"Azeddine Loulijat , Abdelilah Hilali , Mohamed Makhad , Hamid Chojaa , Said Mahfoud , Mishari Metab Almalki , Almoataz Y. Abdelaziz , Mahmoud A. Mossa","doi":"10.1016/j.sciaf.2025.e02745","DOIUrl":"10.1016/j.sciaf.2025.e02745","url":null,"abstract":"<div><div>In order to protect a doubly fed induction generator (DFIG) against voltage drops, it is essential to maintain its transient stability. The passive \"crowbar and dc-chopper\" technique has been employed to protect DFIGs. However, it may not be sufficient for some of the transient profiles. For this reason, the Low Voltage Ride Through (LVRT) has been employed by implementing Control of Flux Neutralization Current (CFNC) for transient response assessment. Moreover, the induced electromotive forces (IEFs) in both circuits (stator and rotor) were modeled on the DFIG, and the comparative performance of the DFIG models with and without CFNC was examined. The system behavior was examined for symmetrical three-phase faults, considering the cases with and without the stator/rotor coupling dynamics. This study uses numerical modeling and time-domain simulations with MATLAB/Simulink to analyze the transient behavior of the DFIG system under fault conditions. No experimental tests have been carried out, and future work will aim at a real-time implementation to assess practical feasibility. DFIG quantities were analyzed and compared, including 0.69 kV output voltage, mechanical speed response, electromagnetic torque variations, rotor and stator direct quadrature (d-q) axis currents, 22 kV bus terminal voltage, and, a DC-Link voltage. The results reveal that CFNC reduces the duration of oscillations by more than 50%, stabilizing currents in 1.18 s instead of 3.5 s and the DC-Link voltage in 1.1 s instead of 3.5 s, significantly improving LVRT capability and transient stability.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02745"},"PeriodicalIF":2.7,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942182","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}

引用次数: 0

Geospatial technology-based identification of groundwater potential zone in the Upper Dawa River Basin, Southern Ethiopia 基于地理空间技术的埃塞俄比亚南部达瓦河上游盆地地下水潜力带识别

IF 2.7

Scientific African Pub Date : 2025-05-08 DOI: 10.1016/j.sciaf.2025.e02747

Debisa Debela , Fikadu Woldemariyam Wodessa , Shankar Karuppannan , Dechasa Diriba

{"title":"Geospatial technology-based identification of groundwater potential zone in the Upper Dawa River Basin, Southern Ethiopia","authors":"Debisa Debela , Fikadu Woldemariyam Wodessa , Shankar Karuppannan , Dechasa Diriba","doi":"10.1016/j.sciaf.2025.e02747","DOIUrl":"10.1016/j.sciaf.2025.e02747","url":null,"abstract":"<div><div>Groundwater (GW) is a vital freshwater resource and essential for meeting domestic, irrigation, and industrial demands. As the demand for water rises, evaluating groundwater potential (GWP) and aquifer productivity becomes increasingly important. This research focuses on mapping groundwater potential zones (GWPZ) in the Upper Dawa River Basin (UDRB), Southern Ethiopia, utilizing a Geographic Information System (GIS)-based Analytical Hierarchy Process (AHP). Seven factors influencing GW availability, recharge, and distribution were considered: drainage density(DD), geology(GL), lineament density(LD), soil type, land use/land cover(LULC), rainfall, and slope. The WOA (weighted overlay analysis) tool in ArcGIS 10.8 generates the final GWPZ map. The results identified five categories of GWPZ: very low, low, moderate, high, and very high, covering 0.26 %, 45.9 %, 8.8 %, 16.34 %, and 28.08 % of the area under study, respectively. The volcanic terrain in the north and northwest, the limestone terrain in the southeast, and patchy or elongated small areas in the basement terrain in the center and south of the research area were mapped as high to very high GWPZs. Conversely, a significant portion of the basement terrain was classified as low-very low GWP. The GWPM (groundwater potential map) accuracy is assessed by utilizing the area under the curve (AUC) approach, resulting in an AUC value of 0.834, indicating a dependable outcome. The findings of this research contribute to ongoing efforts to ensure sustainable water sources for vulnerable communities in the area under investigation.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02747"},"PeriodicalIF":2.7,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929588","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}

引用次数: 0

Removal of BOD, TDS, and phosphate from industrial parks wastewater by using a combined sono-pulsed electrocoagulation method 联合超声脉冲电凝法去除工业园区废水中的BOD、TDS和磷酸盐

IF 2.7

Scientific African Pub Date : 2025-05-05 DOI: 10.1016/j.sciaf.2025.e02741

Hawi Etana Debela , Firomsa Bidira , Perumal Asaithambi

{"title":"Removal of BOD, TDS, and phosphate from industrial parks wastewater by using a combined sono-pulsed electrocoagulation method","authors":"Hawi Etana Debela , Firomsa Bidira , Perumal Asaithambi","doi":"10.1016/j.sciaf.2025.e02741","DOIUrl":"10.1016/j.sciaf.2025.e02741","url":null,"abstract":"<div><div>Wastewater treatment is essential to the preservation of ecosystems and sustainable water management methodologies. It significantly affects both the preservation of water supplies and the reduction of water pollution. The processes of sono-pulsed electrocoagulation (S-PEC) were examined in this work to focuses on how much biological oxygen demand (BOD), phosphate (PO<sub>3</sub><sup>-</sup>), and total dissolved solids (TDS) removed. The effects of initial pH, electrolysis time, and current as well as other experimental factors was determined for the highest percentage removal efficiency. The study found that the values of variables at optimal conditions were achieved the maximum removal efficiency used by the assisted S-PEC process. The optimal values for the highest removal percentages of the results for PO<sub>3</sub><sup>-</sup>, TDS, and BOD were 99.70 %, 97.44 %, and 95.49 %, respectively, at pH = 7, electrolysis time = 40 min, and current intensity = 0.5 A. Overall, these findings show how much more effective the S-PEC is and how feasible it is to remove contaminants from industrial wastewater. The ultrasound waves and electrochemistry are used in the wastewater treatment process known as S-PEC to increase efficiency. For the most effective outcomes, it was essential to optimize variables including pH, duration, and current intensity, which lowers energy usage and operating expenses.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02741"},"PeriodicalIF":2.7,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923607","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}

引用次数: 0

Allopurinol as cardioprotective agent in chronic coronary syndrome: In silico evaluation of its potential as Keap1/Nrf2 modulator 别嘌呤醇作为慢性冠脉综合征的心脏保护剂：其作为Keap1/Nrf2调节剂潜力的计算机评价

IF 2.7

Scientific African Pub Date : 2025-05-05 DOI: 10.1016/j.sciaf.2025.e02743

Kannan O. Ahmed , Mohammed A. Almogaddam , Hagar M. Mohamed , Bayan E. Ainousah , Gamal A. Mohamed , Sabrin R. M. Ibrahim , Nawal A. Alharbi , Toga K. Mohamed , Bashir A. Yousef , Khalid Al Balushi , Abdulrahim A. Alzain

{"title":"Allopurinol as cardioprotective agent in chronic coronary syndrome: In silico evaluation of its potential as Keap1/Nrf2 modulator","authors":"Kannan O. Ahmed , Mohammed A. Almogaddam , Hagar M. Mohamed , Bayan E. Ainousah , Gamal A. Mohamed , Sabrin R. M. Ibrahim , Nawal A. Alharbi , Toga K. Mohamed , Bashir A. Yousef , Khalid Al Balushi , Abdulrahim A. Alzain","doi":"10.1016/j.sciaf.2025.e02743","DOIUrl":"10.1016/j.sciaf.2025.e02743","url":null,"abstract":"<div><div>Chronic coronary syndrome (CCS), a leading cause of global morbidity and mortality, is closely linked to oxidative stress and hyperuricemia. Despite mixed clinical outcomes, allopurinol, a xanthine oxidase inhibitor, has shown potential cardiovascular benefits beyond urate reduction. This study investigates allopurinol’s molecular interactions with the Keap1/Nrf2 pathway, a key regulator of antioxidant responses, using computational approaches. Molecular docking (Glide XP, Schrödinger Maestro) and dynamics simulations (Desmond, OPLS4 force field) analyzed allopurinol’s binding to the Keap1 kelch domain, comparing it to a co-crystallized ligand and inhibitor KI696. Docking revealed moderate affinity for allopurinol (−5.372 kcal/mol), driven by hydrogen bonds (ARG415, SER555) and hydrophobic interactions. Molecular dynamics simulations (100 ns) demonstrated stable binding, with an average RMSD of 3.3 Å. Persistent interactions, including hydrogen bonds with ARG415 and SER555, highlighted allopurinol’s dynamic stability. These findings propose allopurinol as a Keap1 inhibitor, potentially mitigating oxidative stress in CCS. Further experimental is recommended to validate allopurinol’s role in CCS management and bridging computational evidence with clinical application.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02743"},"PeriodicalIF":2.7,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143923604","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}

引用次数: 0

Evaluating the influence of organisational resources and learning capabilities on the performance of small, micro, and medium enterprises (SMMEs) in Ghana 评估加纳组织资源和学习能力对小型、微型和中型企业绩效的影响

IF 2.7

Scientific African Pub Date : 2025-05-05 DOI: 10.1016/j.sciaf.2025.e02740

Johnson Yeboah, Luther-King Junior Zogli

引用次数: 0

Asymmetric dependence between commodity prices and selected macroeconomic variables in Ghana 商品价格与加纳选定宏观经济变量之间的不对称依赖关系

IF 2.7

Scientific African Pub Date : 2025-05-05 DOI: 10.1016/j.sciaf.2025.e02739

Samuel Duku Yeboah, Michael Provide Fumey, Stephen Antwi Winful, Isaac Christopher Otoo, Peterson Owusu Junior

{"title":"Asymmetric dependence between commodity prices and selected macroeconomic variables in Ghana","authors":"Samuel Duku Yeboah, Michael Provide Fumey, Stephen Antwi Winful, Isaac Christopher Otoo, Peterson Owusu Junior","doi":"10.1016/j.sciaf.2025.e02739","DOIUrl":"10.1016/j.sciaf.2025.e02739","url":null,"abstract":"<div><div>The nexus between commodity prices (CDP) and exchange rates (EXE) is critical, particularly for a commodity-exporting nation like Ghana. This study investigates the asymmetric dependence between commodity prices (Cocoa, Crude Oil, Gold, Petrol, and Diesel) inflation and exchange rates in Ghana. The study employed monthly frequency data from 2003 to 2023 on commodity prices, inflation, and exchange rates. The research unveils fresh insights into this complex nexus by employing a quantile-on-quantile estimation. The findings challenge the conventional understanding of a uniform positive correlation, revealing more complex dynamics. Diesel and petrol prices positively impact the Ghanaian cedi's exchange rate, which implies a depreciation of the Ghanaian cedi currency. In contrast, cocoa and crude oil prices demonstrate a predominantly negative influence, indicating an appreciation of the Cedi currency. Furthermore, the study uncovers feedback effects and bidirectional relationships between specific commodity prices and exchange rates, highlighting potential self-reinforcing cycles. Outstandingly, incorporating inflation as a factor reveals a positive link between inflation and the exchange rate and a feedback effect, signifying a depreciation of the Cedi currency. These conclusions have policy implications for Ghana's policymakers, financiers, and stakeholders, offering valuable insights to inform policy decisions, risk mitigation strategies, and investment decisions.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02739"},"PeriodicalIF":2.7,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143929585","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}

引用次数: 0

Socio-ecological factors contributing to the use of slash-and-burn as cropland preparation practice in Burkina Faso 社会生态因素导致在布基纳法索使用刀耕火种作为农田准备做法

IF 2.7

Scientific African Pub Date : 2025-05-03 DOI: 10.1016/j.sciaf.2025.e02736

Pawend-taoré Christian Bougma, Loyapin Bondé, Valaire Séraphin Ouehoudja Yaro, Bruno Nikiéma, Oumarou Ouédraogo

{"title":"Socio-ecological factors contributing to the use of slash-and-burn as cropland preparation practice in Burkina Faso","authors":"Pawend-taoré Christian Bougma, Loyapin Bondé, Valaire Séraphin Ouehoudja Yaro, Bruno Nikiéma, Oumarou Ouédraogo","doi":"10.1016/j.sciaf.2025.e02736","DOIUrl":"10.1016/j.sciaf.2025.e02736","url":null,"abstract":"<div><div>Biomass burning (BB) is a widely practiced agricultural method for clearing cropland and a major source of carbon dioxide (CO₂) emissions, contributing to climate change (CC). Understanding the key socio-ecological factors influencing BB use and farmers' knowledge of CC is crucial for decision-making on sustainable land management. This study aimed to: (i) assess the socio-ecological factors influencing the use of biomass burning, (ii) examine farmers' knowledge of the effects of biomass burning on CC, and (iii) identify local alternative practices to reduce BB. A total of 204 smallholder farmers were interviewed across two contrasting climatic zones, Sudanian and Sudano-Sahelian, in Burkina Faso using a semi-structured technique. Our findings revealed that 47.55 % of farmers use fire for land preparation, with cropland age (β = -0.955, <em>p</em> < 0.05), and gender (β = -0.733, <em>p</em> < 0.01), being the primary socio-ecological factors influencing the use of this practice. Smallholders reported that faster field clearance (41 %) and improved soil fertility (23 %) were the main reasons for adopting biomass burning. Results also highlighted that education level (β = -0.569, <em>p</em> < 0.05) and access to extension services (β = -1.711, <em>p</em> < 0.05) were the most significant factors influencing farmers' awareness of climate change and greenhouse gas emissions, respectively. Local alternative practices, such as biomass mulching and composting, have been identified as replacements for BB. Raising awareness among farmers about the environmental impact of BB presents a viable mitigation strategy.</div></div>","PeriodicalId":21690,"journal":{"name":"Scientific African","volume":"28 ","pages":"Article e02736"},"PeriodicalIF":2.7,"publicationDate":"2025-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143924451","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}

引用次数: 0

High-efficiency MPPT Using ZVS quasi-resonant converter and PSO algorithm: Simulation and PIL validation 基于ZVS准谐振变换器和PSO算法的高效MPPT：仿真与PIL验证

IF 2.7

Scientific African Pub Date : 2025-05-03 DOI: 10.1016/j.sciaf.2025.e02704

Souhail Barakat , Abdelouahed Mesbahi , Badr N’hili , Ayoub Nouaiti , Mohcine Abouyaakoub

引用次数: 0