期刊文献+
共找到21,802篇文章
< 1 2 250 >
每页显示 20 50 100
The Impacts and Causes of Land Fragmentation on Farm Productivity: Case Review of East African Countries
1
作者 Joseph Mayindo Mayele Jacob B. Kolleh Joel Emmanuel Saburi 《Open Journal of Ecology》 2024年第5期455-482,共28页
This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of c... This report provides an overall assessment of land fragmentation problems in East Africa. Many parts of East Africa have become highly fragmented, putting development systems and activities in these areas at risk of complete collapse. Land fragmentation occurs when land gets converted for agriculture, industrialization, or urbanization, invaded by non-local plants, or enclosed for individual use and by subdividing farmlands into subsequent smaller units called parcels with varying average farm sizes. Fragmentation results from inappropriate agricultural development processes and ineffective land use planning that fails to recognize how farmland is used, and the importance of its interconnected areas. Insecurity of tenure and resource rights are key factors in making this possible. Land fragmentation is one of the key reasons why the ability of most resources in East Africa becomes scarcer, and those remaining become “privatized” by more powerful community members—keen to maintain their access to them. Such individualistic attitudes are new and disadvantage the poorest even further by affecting the traditional customary safety nets and agricultural outputs. Neither the government nor customary governance systems effectively protect resource access for the poorest. This review summary report identifies the key causes, measures, and implications, government interventions, and the common remedies to land fragmentation problems in the East African Countries of Kenya, Uganda, Rwanda, and Tanzania including neighboring Ethiopia, and the Sudan. The findings indicated from 2005 to 2015, the population kept increasing for all the named countries in East Africa with Rwanda and Uganda having a substantial increase in population density. The study review further explores the trend in the performance of agriculture by average farm sizes within the intervals of five years by highlighting their strong linkages and found that the average farm size has declined drastically, especially for Kenya. This can only mean that small farms kept becoming smaller and smaller and that there were more small-scale farmers. The results further depicted that the major and commonly cultivated food crops among the East African countries include maize, sorghum, rice, cassava, sweet potatoes, bananas, Irish potatoes, beans, peas, etc., with maize yields (Mt/ha) in 2003 for Uganda being the highest (1.79 Mt/ha) and the lowest in Rwanda (0.77 Mt/ha) respectively. Therefore, from the review results, recommendations are being made as to how the negative impacts of land fragmentation on agricultural productivity can be reduced or mitigated. One way is by community sensitization and awareness about the importance of land consolidation and its proposition on farm productivity. 展开更多
关键词 Land Fragmentation Land Consolidation farm Productivity INDUSTRIALIZATION Impacts CAUSES Average farm Size Population East Africa
下载PDF
Smart Farming for Sustainable Rice Production:An Insight into Application,Challenge,and Future Prospect
2
作者 Norhashila HASHIM Maimunah Mohd ALI +4 位作者 Muhammad Razif MAHADI Ahmad Fikri ABDULLAH Aimrun WAYAYOK Muhamad Saufi Mohd KASSIM Askiah JAMALUDDIN 《Rice science》 SCIE CSCD 2024年第1期47-61,共15页
Rice has a huge impact on socio-economic growth,and ensuring its sustainability and optimal utilization is vital.This review provides an insight into the role of smart farming in enhancing rice productivity.The applic... Rice has a huge impact on socio-economic growth,and ensuring its sustainability and optimal utilization is vital.This review provides an insight into the role of smart farming in enhancing rice productivity.The applications of smart farming in rice production including yield estimation,smart irrigation systems,monitoring disease and growth,and predicting rice quality and classifications are highlighted.The challenges of smart farming in sustainable rice production to enhance the understanding of researchers,policymakers,and stakeholders are discussed.Numerous efforts have been exerted to combat the issues in rice production in order to promote rice sector development.The effective implementation of smart farming in rice production has been facilitated by various technical advancements,particularly the integration of the Internet of Things and artificial intelligence.The future prospects of smart farming in transforming existing rice production practices are also elucidated.Through the utilization of smart farming,the rice industry can attain sustainable and resilient production systems that could mitigate environmental impact and safeguard food security.Thus,the rice industry holds a bright future in transforming current rice production practices into a new outlook in rice smart farming development. 展开更多
关键词 rice production smart farming food security agriculture sustainability
下载PDF
Mobile genetic elements facilitate the transmission of antibiotic resistance genes in multidrug-resistant Enterobacteriaceae from duck farms
3
作者 Xin’er Zheng Dingting Xu +5 位作者 Jinchang Yan Min Qian Peng Wang Davood Zaeim Jianzhong Han Daofeng Qu 《Food Science and Human Wellness》 SCIE CSCD 2024年第2期729-735,共7页
Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms i... Multidrug-resistant(MDR)Enterobacteriaceae critically threaten duck farming and public health.The phenotypes,genotypes,and associated mobile genetic elements(MGEs)of MDR Enterobacteriaceae isolated from 6 duck farms in Zhejiang Province,China,were investigated.A total of 215 isolates were identified as Escherichia coli(64.65%),Klebsiella pneumoniae(12.09%),Proteus mirabilis(10.23%),Salmonella(8.84%),and Enterobacter cloacae(4.19%).Meanwhile,all isolates were resistant to at least two antibiotics.Most isolates carried tet(A)(85.12%),blaTEM(78.60%)and sul1(67.44%)resistance genes.Gene co-occurrence analysis showed that the resistance genes were associated with IS26 and integrons.A conjugative IncFII plasmid pSDM004 containing all the above MGEs was detected in Proteus mirabilis isolate SDM004.This isolate was resistant to 18 antibiotics and carried the blaNDM-5 gene.MGEs,especially plasmids,are the primary antibiotic resistance gene transmission route in duck farms.These findings provide a theoretical basis for the rational use of antibiotics in farms which are substantial for evaluating public health and food safety. 展开更多
关键词 Duck farm Mobile genetic element Antibiotic resistance gene PLASMID Food safety
下载PDF
Technical efficiency of cocoa farms at varying elevation levels in Davao City, Philippines: implications to sustainable upland farming systems
4
作者 Francis Levi A.DURANO Jon Marx SARMIENTO +1 位作者 Larry N.DIGAL Pedro A.ALVIOLA IV 《Journal of Mountain Science》 SCIE CSCD 2024年第1期33-48,共16页
Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa ... Elevation is one of many components that influence agriculture, and this in turn affects the level of both inputs and outputs of farmers. This article focuses on the productivity and technical efficiency of 100 cocoa farms using cross-sectional data from areas ranging from 190 to 1021 m above sea level which were classified as low, medium, and high elevation in Davao City, considered as the chocolate capital of the Philippines. Using stochastic frontier analysis, the results showed that the cost of inputs per ha and the number of cocoa trees per ha significantly increase yield. Farms at high elevations were less technically efficient, as this entails lower temperatures and increased rainfall, and cocoa farming in those areas and conditions can be more challenging, especially with changes in farming practices, terrain, and distance to markets. Other significant variables were age of cocoa farms, married farmers, and age of the farmers. Older farms may be more developed, farmers who are married benefit from their spouses being able to readily contribute as farm labor, and lastly, older farmers' inefficiency may likely stem from nonadaptation of newer farming practices. With an average technical efficiency of 0.61, 0.63, and 0.26 in low, medium, and high elevation areas, respectively, farmers therefore have an incentive to improve farm practices and consider topographical variations found in high elevation areas. Recommendations for the improvement of technical efficiency of cocoa farms are better connectivity to markets, enhancing farm practices, and continuation and improvement of government programs on cocoa with an added emphasis on research. For farmers in high elevation areas, mitigating solutions such as sustainable agriculture practices and ecolabelling are key to improving efficiency and minimizing the potential negative impact on upland farming systems. Moreover, such adaptation measures may also contribute to sustainability of cocoa farming in high elevation areas. 展开更多
关键词 Cocoa farms Cobb-Douglas production function ELEVATION Philippines Stochastic frontier analysis Technical efficiency
下载PDF
Transient Stability Preventive Control of Wind Farm Connected Power System Considering the Uncertainty
5
作者 Yuping Bian Xiu Wan Xiaoyu Zhou 《Energy Engineering》 EI 2024年第6期1637-1656,共20页
To address uncertainty as well as transient stability constraints simultaneously in the preventive control of windfarm systems, a novel three-stage optimization strategy is established in this paper. In the first stag... To address uncertainty as well as transient stability constraints simultaneously in the preventive control of windfarm systems, a novel three-stage optimization strategy is established in this paper. In the first stage, the probabilisticmulti-objective particle swarm optimization based on the point estimate method is employed to cope with thestochastic factors. The transient security region of the system is accurately ensured by the interior point methodin the second stage. Finally, the verification of the final optimal objectives and satisfied constraints are enforcedin the last stage. Furthermore, the proposed strategy is a general framework that can combine other optimizationalgorithms. The proposed methodology is tested on the modified WSCC 9-bus system and the New England 39-bussystem. The results verify the feasibility of the method. 展开更多
关键词 Transient preventive control chance-constrained programming multi-objective PSO TSCOPF wind farm
下载PDF
GNN Representation Learning and Multi-Objective Variable Neighborhood Search Algorithm for Wind Farm Layout Optimization
6
作者 Yingchao Li JianbinWang HaibinWang 《Energy Engineering》 EI 2024年第4期1049-1065,共17页
With the increasing demand for electrical services,wind farm layout optimization has been one of the biggest challenges that we have to deal with.Despite the promising performance of the heuristic algorithm on the rou... With the increasing demand for electrical services,wind farm layout optimization has been one of the biggest challenges that we have to deal with.Despite the promising performance of the heuristic algorithm on the route network design problem,the expressive capability and search performance of the algorithm on multi-objective problems remain unexplored.In this paper,the wind farm layout optimization problem is defined.Then,a multi-objective algorithm based on Graph Neural Network(GNN)and Variable Neighborhood Search(VNS)algorithm is proposed.GNN provides the basis representations for the following search algorithm so that the expressiveness and search accuracy of the algorithm can be improved.The multi-objective VNS algorithm is put forward by combining it with the multi-objective optimization algorithm to solve the problem with multiple objectives.The proposed algorithm is applied to the 18-node simulation example to evaluate the feasibility and practicality of the developed optimization strategy.The experiment on the simulation example shows that the proposed algorithm yields a reduction of 6.1% in Point of Common Coupling(PCC)over the current state-of-the-art algorithm,which means that the proposed algorithm designs a layout that improves the quality of the power supply by 6.1%at the same cost.The ablation experiments show that the proposed algorithm improves the power quality by more than 8.6% and 7.8% compared to both the original VNS algorithm and the multi-objective VNS algorithm. 展开更多
关键词 GNN representation learning variable neighborhood search multi-objective optimization wind farm layout point of common coupling
下载PDF
Identification of Microorganisms in Poultry Farms in N’djamena and the Border Areas of Hadjer-Lamis and Chari-Baguirmi Chad
7
作者 Abakar Abbo Zakaria Bebanto Antipas Ban-Bo +2 位作者 Nadine Terei Bongo Naré Richard Gandolo Abdelsalam Adoum Doutoum 《Journal of Agricultural Chemistry and Environment》 2024年第2期223-234,共12页
Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real... Introduction: On the outskirts of Ndjamena, semi-industrial poultry farming and traditional poultry farming are practised informally on almost all poultry farms in Chad. This type of poultry farming is faced with real health problems attributable to a lack of monitoring of the vaccination schedule, inadequate compliance with biosecurity measures and poor application of the Ichikawa rule based on the 5 M’s. Objective: The aim of this article is to identify the microorganisms responsible for contamination of poultry farms in the study area. Method: The study was carried out from 28/04/2022 to 31/01/2023 on the basis of 300 samples taken from feed, drinking water, droppings and scrapings from poultry housing surfaces in the 30 farms that served as a framework for our research. Sampling was of the simple random type, and farms were selected on the basis of the farmers’ consent. The data were recorded on pre-established survey forms. Our study was cross-sectional, descriptive and prospective. Bacteria were isolated using the reference method NF EN ISO 6579 for Salmonella spp. and cultured on the specific medium eosin methylene blue (EMB) for Escherichia coli, Pseudomonas and Citrobacter freundii. Results: The following results emerged from this study: Escherichia coli (5.33%), Pseudomonas (1.33%), Citrobacter freundii (12%) and Salmonella paratyphi (21.68%). Conclusion: Of the 300 samples analysed, 121 (40.33%) were contaminated with pathogens. This high level of contamination is a health problem. The study shows that biosecurity is less satisfactory on the farms visited. Nevertheless, farms with a very satisfactory level of biosafety ensure food safety and variety for the population. 展开更多
关键词 Microorganisms Identification Poultry farms N’Djamena Hadjer-Lamis Chari-Baguirmi(Chad)
下载PDF
Wake Effects on A Hybrid Semi-Submersible Floating Wind Farm with Multiple Hub Heights
8
作者 XU Xiao-sen GU Jia-yang +5 位作者 LING Hong-jie YANG Pu-yi WANG Shuai-shuai XING Yi-han Oleg GAIDAI ZHANG Zhong-yu 《China Ocean Engineering》 SCIE EI CSCD 2023年第1期101-114,共14页
Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind... Wind farms generally consist of a single turbine installed with the same hub height. As the scale of turbines increases,wake interference between turbines becomes increasingly significant, especially for floating wind turbines(FWT).Some researchers find that wind farms with multiple hub heights could increase the annual energy production(AEP),while previous studies also indicate that wake meandering could increase fatigue loading. This study investigates the wake interaction within a hybrid floating wind farm with multiple hub heights. In this study, FAST.Farm is employed to simulate a hybrid wind farm which consists of four semi-submersible FWTs(5MW and 15MW) with two different hub heights. Three typical wind speeds(below-rated, rated, and over-rated) are considered in this paper to investigate the wake meandering effects on the dynamics of two FWTs. Damage equivalent loads(DEL) of the turbine critical components are computed and analyzed for several arrangements determined by the different spacing of the four turbines. The result shows that the dynamic wake meandering significantly affects downstream turbines’ global loadings and load effects. Differences in DEL show that blade-root flapwise bending moments and mooring fairlead tensions are sensitive to the spacing of the turbines. 展开更多
关键词 hybrid floating wind farm wake meandering multiple hub heights floating wind turbine FAST.farm fatigue
下载PDF
Influences of large-scale farming on carbon emissions from cropping:Evidence from China
9
作者 LI Ya-ling YI Fu-jin YUAN Chong-jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第10期3209-3219,共11页
Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.T... Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model.Furthermore,the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis.Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases,which is dominated by the changes in the carbon emission from fertilizer.Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend,although it is conducive to reducing total carbon emission in the long run.The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation,which are also informative to other developing countries with small farm size. 展开更多
关键词 farm size carbon emission agricultural transition
下载PDF
Paneth cells in farm animals:current status and future direction
10
作者 Chenbin Cui Lindeng Li +5 位作者 Lin Wu Xinru Wang Yao Zheng Fangke Wang Hongkui Wei Jian Peng 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2023年第6期2263-2275,共13页
A healthy intestine plays an important role in the growth and development of farm animals.In small intestine,Paneth cells are well known for their regulation of intestinal microbiota and intestinal stem cells(ISCs).Al... A healthy intestine plays an important role in the growth and development of farm animals.In small intestine,Paneth cells are well known for their regulation of intestinal microbiota and intestinal stem cells(ISCs).Although there has been a lot of studies and reviews on human and murine Paneth cells under intestinal homeostasis or disorders,little is known about Paneth cells in farm animals.Most farm animals possess Paneth cells in their small intestine,as identified by various staining methods,and Paneth cells of various livestock species exhibit noticeable differences in cell shape,granule number,and intestinal distribution.Paneth cells in farm animals and their antimicrobial peptides(AMPs)are susceptible to multiple factors such as dietary nutrients and intestinal infection.Thus,the comprehensive understanding of Paneth cells in different livestock species will contribute to the improvement of intestinal health.This review first summarizes the current status of Paneth cells in pig,cattle,sheep,horse,chicken and rabbit,and points out future directions for the investigation of Paneth cells in the reviewed animals. 展开更多
关键词 Antimicrobial peptide farm animal Intestinal organoid INTESTINE Paneth cell
下载PDF
Effect of Combined Application of Organic Farming Aid (OFA) and Inorganic Fertilizers on the Growth and Yield of Maize and Soil Microbial Properties in the Guinea Savannah Agro-Ecological Zone of Ghana
11
作者 O. A. Amoako J. Adjebeng-Danquah +8 位作者 R. Y. Agyare E. K. Akley H. Abeka Julius Yirzagla T. K. Tengey P. Teinor R. Alhassan A. A. Ibrahim C. Naapoal 《American Journal of Plant Sciences》 2023年第10期1180-1206,共27页
The aim of the study was to evaluate the effect of different rates of organic farming aid (OFA) and inorganic fertilizer on the productivity of maize, chemical and microbial properties of soil for higher economic valu... The aim of the study was to evaluate the effect of different rates of organic farming aid (OFA) and inorganic fertilizer on the productivity of maize, chemical and microbial properties of soil for higher economic value. Field experiments were conducted during the 2020 and 2021 cropping seasons at the research fields of CSIR-Savanna Agricultural Research Institute located at Nyankpala in the Guinea savannah agroecology of Ghana. The study consisted of five treatment combinations: full rate of OFA, full rate of NPK, 1/2 OFA + 1/2 NPK, full OFA + 1/2 NPK and a control (no OFA and no NPK) which were arranged in a randomized complete block design with four replications. Analysis of variance indicated significant (P 0.05) treatment and year interaction effect for all the growth parameters except for plant height, leaf area and leaf area index. Apart from hundred seed weight, treatment and year interaction effect for all the yield and yield components was significant (P 0.05). Application of full rate of NPK (90:60:60) resulted in the highest grain yield of 4960 kg·ha<sup>-1</sup>, however it was statistically similar to those obtained by the combined application of full rate of OFA (250 ml·ha<sup>-1</sup>) + 1/2 NPK and 1/2 OFA + 1/2 NPK with grain yield of 4856 kg·ha<sup>-1</sup> and 4639 kg·ha<sup>-1</sup> respectively. There was also a yield advantage of 197. 5%, 191.3%, 178.3 and 79.1% over the control for full NPK rate, full OFA rate + 1/2 NPK rate, 1/2 OFA rate + 1/2 NPK and full OFA rate respectively. Application of full OFA rate + 1/2 NPK enhanced soil basal respiration (evolved CO<sub>2</sub>) and mineralizable C, implying that, combination of full OFA rate and NPK fertilizer would be necessary to boost soil microbial activity and soil labile nutrient pool (labile C pool). This suggests that combined use of full OFA rate + 1/2 NPK fertilizer can be a better strategic tool for improving soil quality. The highest benefit cost ratios (BCR) of 2.58 and 3.77 were obtained following the application of full OFA rate + 1/2 NPK and 1/2 OFA rate + 1/2 NPK respectively. Hence, it could be concluded that complementary use of OFA and NPK is more profitable than using single inputs (either OFA or NPK). Thus, in promoting technology packages to farmers, development practitioners must carefully consider the complementary of inputs that are cost-effective but economically rewarding. 展开更多
关键词 Organic farming Aid Labile C Pool Wood Vinegar Combined Application
下载PDF
Information-Centric IoT-Based Smart Farming with Dynamic Data Optimization
12
作者 Souvik Pal Hannah VijayKumar +3 位作者 D.Akila N.Z.Jhanjhi Omar A.Darwish Fathi Amsaad 《Computers, Materials & Continua》 SCIE EI 2023年第2期3865-3880,共16页
Smart farming has become a strategic approach of sustainable agriculture management and monitoring with the infrastructure to exploit modern technologies,including big data,the cloud,and the Internet of Things(IoT).Ma... Smart farming has become a strategic approach of sustainable agriculture management and monitoring with the infrastructure to exploit modern technologies,including big data,the cloud,and the Internet of Things(IoT).Many researchers try to integrate IoT-based smart farming on cloud platforms effectively.They define various frameworks on smart farming and monitoring system and still lacks to define effective data management schemes.Since IoT-cloud systems involve massive structured and unstructured data,data optimization comes into the picture.Hence,this research designs an Information-Centric IoT-based Smart Farming with Dynamic Data Optimization(ICISF-DDO),which enhances the performance of the smart farming infrastructure with minimal energy consumption and improved lifetime.Here,a conceptual framework of the proposed scheme and statistical design model has beenwell defined.The information storage and management with DDO has been expanded individually to show the effective use of membership parameters in data optimization.The simulation outcomes state that the proposed ICISF-DDO can surpass existing smart farming systems with a data optimization ratio of 97.71%,reliability ratio of 98.63%,a coverage ratio of 99.67%,least sensor error rate of 8.96%,and efficient energy consumption ratio of 4.84%. 展开更多
关键词 Smart farming data optimization information management internet of things CLOUD
下载PDF
The role of time preferences in contract breach:Evidence from Chinese poultry farmers participating in contract farming
13
作者 HOU Jing ZHOU Li +1 位作者 Jennifer IFFT YING Rui-yao 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第2期623-641,共19页
Farmers’contract breach behavior is cited as one of the major stumbling blocks in the sustainable expansion of contract farming in many developing countries.This paper examines farmers’contract breach decisions from... Farmers’contract breach behavior is cited as one of the major stumbling blocks in the sustainable expansion of contract farming in many developing countries.This paper examines farmers’contract breach decisions from the perspective of time preferences.The empirical analysis is based on a household survey and economic field experiments of poultry households participating in contract farming conducted in Jiangsu Province,China.A discounted utility model and a maximum likelihood technique are applied to estimate farmers’time preferences and the effect of time preferences on contract breach in the production and sales phases are explored with a bivariate probit model.The results show that,on average,the poultry farmers in the sample are generally present biased and impatient regarding future utility.The regression results show that farmers with a higher preference for the present and a higher discount rate are more likely to breach contracts,and time preferences play a greater role in the production phase than in the sales phase.When considering heterogeneity,specific investments and transaction costs promote contract stability only for farmers with a low degree of impatience.Moreover,compared with large-scale farmers,small-scale farmers’contract breach decisions are more significantly affected by their time preferences.These results have implications for contract stability policies and other issues that are impacted by the linking of behavioral preferences to agricultural decisions. 展开更多
关键词 time preferences contract breach contract farming economic field experiments China
下载PDF
Pollution characteristics and risk assessment of organophosphate esters in aquaculture farms and natural water bodies adjacent to the Huanghe River delta
14
作者 Jinyu CHAO Song FENG +2 位作者 Yingdong HAO Jianing LIN Bin ZHANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2023年第1期251-266,共16页
To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture c... To date,little attention has been paid to the effects of organophosphate esters(OPEs)pollution on aquacultural environment and aquatic product safety.Huanghe(Yellow)River delta area is one of the largest aquaculture centers in China,where ecological security protection is crucial in the national strategy of China.To explore the pollution characteristics,bioaccumulation,and health risks of OPEs in aquaculture farms in the Huanghe River delta and natural water bodies in the adjacent seas,five species of organisms from different farm types nearby the Huanghe River delta,and the corresponding culture water and sediments were sampled in this study.The total concentrations of Σ_(13)OPEs in water,sediments,and organisms were 51.53-272.18 ng/L,52.63-63.17 ng/g dry weight(dw),and 46.82-108.90 ng/g dw,respectively.Among the five types of culture ponds,the water samples from the swimming crab and hairy crab culture ponds exhibited higher OPEs,the concentration of OPEs in the sediments from the few ponds was relatively balanced,and the OPEs in the organism from the holothurian ponds was higher.Tris(1,3-dichloro-2-isopropyl pho sphate)(TDCP)was the main contaminant in water samples and tripropyl phosphate(TPrP)in sediments and organisms.However,trisphenyl phosphate(TPhP)showed the strongest bioaccumulation ability,followed by 2-ethylhexyl diphenyl phosphate(EHDPP)and TPrP.The bioaccumulation capacities of the five species were as follows:prawn>holothurian>hairy crab>swimming crab>carp.These five types of organisms,as main seafood in human consumption,were at low risk of negative impacts of pollution.However,the risk from the mixture of organophosphate flame retardants(OPFRs)still requires more attention due to the increasing consumption and production in the world. 展开更多
关键词 organophosphate esters(OPEs) aquaculture farms BIOACCUMULATION health risk assessment
下载PDF
Can Natural Farming Help to Combat Climate Variability? A Comparison of Natural and Chemical Farming in Andhra Pradesh, India
15
作者 Zakir Hussain Vijay Kumar Thallam +4 位作者 Reshma Soma Kiranmai Jirra Himabindu Anisetti Bhavana Boppana Neelima Dendeti 《Agricultural Sciences》 2023年第9期1321-1342,共22页
A study was conducted to compare the potential of natural farming versus conventional chemical farming to withstand adverse climate effects. The study investigated two cyclones, namely cyclone Pethai and cyclone Titli... A study was conducted to compare the potential of natural farming versus conventional chemical farming to withstand adverse climate effects. The study investigated two cyclones, namely cyclone Pethai and cyclone Titli of 2018, which caused significant damage to Andhra Pradesh’s coastal corridor. In addition, the impact of heavy rainfall in 2021 on two different farming systems was studied. The worst-affected Paddy crop regions where these cyclones caused severe damage were surveyed. Multiple linear regression was utilized to investigate predictors including crop damage, wind damage, submergence, and yield loss in these two agricultural systems during these two cyclonic and heavy rainfall events. The study indicated that natural farming practices were more resilient to climate variability than conventional chemical farming techniques. The study showed a statistically significant difference (p < 0.001) between these two farming systems in terms of damage caused due to climate variabilities. 展开更多
关键词 Natural farming Climate Resilience CYCLONES Heavy Rainfall
下载PDF
Gender Perspectives of Vulnerability to Climate Change: A Descriptive Evidence from Farming Households at Ikpayongo Community in Gwer Lga, Benue State, Nigeria
16
作者 Monday Akpegi Onah Elizabeth Jeiyol +1 位作者 Odeh Adimanyi Chiviter Ukange 《American Journal of Climate Change》 2023年第1期116-139,共24页
Climate change impact and risks on agricultural livelihood affect women and men disproportionately and often to the disadvantage of women and girls. Consequently, this study assessed gender perspectives of vulnerabili... Climate change impact and risks on agricultural livelihood affect women and men disproportionately and often to the disadvantage of women and girls. Consequently, this study assessed gender perspectives of vulnerability to climate change of farming households at Ikpayongo community in Gwer local government area, Benue State, Nigeria using descriptive approach. The study identified a total of 120 male-headed and female-headed farming households across four neighbourhoods and administered structured questionnaire on them using simple random sampling method, while data analysis was done using descriptive statistics. The results indicate lower education and income status among female-headed households, though male-headed households have high household size. Both sexes have relatively equal access to land for farming, however men have large farm size compared to women. The major crops cultivated by men were rice and yam, while women cultivated largely groundnut and cassava. Women are more exposed and sensitive to climate-related hazards such as floods and heat stress due to the location of their farms. The result further shows that males possess better adaptive capacity given their higher incomes, social networks and more access to training/capacity building programmes and credit facilities. The study concludes that female-headed farming households are more vulnerable to climate change and variability than male-headed farming households due to higher exposure and a lower adaptive capacity. Programme and policies to improve women access to credit facilities and relevant training to boost their adaptive capacity and build resilience are highly recommended. This would also limit exposure with attendant reduction in vulnerability. 展开更多
关键词 Climate Change GENDER farming Households VULNERABILITY Adaptive Capacity
下载PDF
Wind farm active power dispatching algorithm based on Grey Incidence
17
作者 Binbin Zhang Mengxin Jia +2 位作者 Chaobo Chen Kun Wang Jichao Li 《Global Energy Interconnection》 EI CAS CSCD 2023年第2期175-183,共9页
This study proposes a wind farm active power dispatching(WFAPD) algorithm based on the grey incidence method, which does not rely on an accurate mathematical model of wind turbines. Based on the wind turbine start-sto... This study proposes a wind farm active power dispatching(WFAPD) algorithm based on the grey incidence method, which does not rely on an accurate mathematical model of wind turbines. Based on the wind turbine start-stop data at different wind speeds, the weighting coefficients, which are the participation degrees of a variable speed system and a variable pitch system in power regulation, are obtained using the grey incidence method. The incidence coefficient curve is fitted by the B-spline function at a full range of wind speeds, and the power regulation capacity of all wind turbines is obtained. Finally, the WFAPD algorithm, which is based on the regulating capacity of each wind turbine, is compared with the wind speed weighting power dispatching(WSWPD) algorithm in MATLAB. The simulation results show that the active power fluctuation of the wind farm is smaller, the rotating speed of wind turbines is smoother, and the fatigue load of highspeed turbines is effectively reduced. 展开更多
关键词 Wind farm Active power dispatching Grey incidence B-spline function
下载PDF
Characteristics of sub-synchronous oscillation in grid-connected wind farm system
18
作者 Yan Gong Qi Huang +1 位作者 Dong-Sheng Cai Bamisile Olusola Olorunfemi 《Journal of Electronic Science and Technology》 EI CSCD 2023年第4期91-101,共11页
With the rapid development of wind power, wind turbines are accompanied by a large quantity of power electronic converters connected to the grid, causing changes in the characteristics of the power system and leading ... With the rapid development of wind power, wind turbines are accompanied by a large quantity of power electronic converters connected to the grid, causing changes in the characteristics of the power system and leading to increasingly serious sub-synchronous oscillation (SSO) problems, which urgently require the generalized classification and characterization of the emerging oscillation problems. This paper classifies and characterizes the emerging types of SSO caused by grid-connected wind turbines to address these issues. Finally, the impact of the typical system parameters changes on the oscillation pattern is analyzed in depth to provide effective support for the subsequent suppression and prevention of SSO. 展开更多
关键词 CHARACTERISTICS CLASSIFICATION Sub-synchronous oscillation(SSO) Typical system parameters Wind farm
下载PDF
Sources of Farm Risk and Management Strategies among Cowpea(Vigna unguiculata SSP)Producers in North East Nigeria
19
作者 RABIU Mohammed Sani MOSES Joseph 《Journal of Agricultural Science and Technology(A)》 2023年第1期30-39,共10页
The study identified sources of farm risks and management strategies used among cowpea producers in North East,Nigeria.Data were collected using structured questionnaires from 595 cowpea producers.Multi-stage sampling... The study identified sources of farm risks and management strategies used among cowpea producers in North East,Nigeria.Data were collected using structured questionnaires from 595 cowpea producers.Multi-stage sampling procedure was used to select cowpea producers for the study.In the first stage purposive sampling was used to select three(3)states from the six(6)states in the region and these states include Adamawa,Bauchi and Gombe States.From these selected states two(2)local governments each were selected based on apriory information on cowpea production from the state Agricultural Development Programs(ADPs)and analysed using descriptive statistics,Likert scale and multiple regression model.The result revealed that,pest and diseases emerged as the common source of production risk at 74%.Also,uncertainty from product price 66%was a major source of marketing risk.Furthermore,inadequate credit was an important financial risk at 54%and lack of cooperative 51%were major sources of both financial and institutional risks.The valid management strategies used in mitigating/coping among cowpea producers were livestock production to complement income,sales of produce,engagement in other jobs/activities,access to ADP’s extension agent among others.Therefore,cowpea production is affected by production/environmental risk,marketing risk,financial risk,institutional risk and human/personnel risk and exhibited risk aversion attitude.The study recommends strategy of developing early varieties,disease resistant crops and products that are resistant to pest both in the farm and storage to raise the productivity of cowpea.Also,cowpea producers’cooperatives should be strengthened with priority given enlightened/educating members,create strong bargaining power for farm products as well as accessing credit facilities.Similarly,inputs such as fertilizers and certified improved high-quality seeds are available and accessible to cowpea producers to increase production and reduce risks. 展开更多
关键词 SOURCES farm risks management bauchi NIGERIA
下载PDF
Research on Asymmetric Fault Location of Wind Farm Collection System Based on Compressed Sensing
20
作者 Huanan Yu Gang Han +1 位作者 Hansong Luo He Wang 《Energy Engineering》 EI 2023年第9期2029-2057,共29页
Aiming at the problem that most of the cables in the power collection systemof offshore wind farms are buried deep in the seabed,whichmakes it difficult to detect faults,this paper proposes a two-step fault location m... Aiming at the problem that most of the cables in the power collection systemof offshore wind farms are buried deep in the seabed,whichmakes it difficult to detect faults,this paper proposes a two-step fault location method based on compressed sensing and ranging equation.The first step is to determine the fault zone through compressed sensing,and improve the datameasurement,dictionary design and algorithmreconstruction:Firstly,the phase-locked loop trigonometric functionmethod is used to suppress the spike phenomenon when extracting the fault voltage,so that the extracted voltage valuewillnot have a large error due to the voltage fluctuation.Secondly,theλ-NIM dictionary is designed by using the node impedancematrix and the fault location coefficient to further reduce the influence of pseudo-fault points.Finally,the CoSaMP algorithmis improved with the generalized Jaccard coefficient to improve the reconstruction accuracy.The second step is to use the ranging equation to accurately locate the asymmetric fault of the wind farm collection system on the basis of determining the fault interval.The simulation results show that the proposedmethod ismore accurate than the compressedsensingmethod andimpedancemethod in fault section location and fault location accuracy,the relative error is reduced from 0.75%to 0.4%,and has a certain anti-noise ability. 展开更多
关键词 Offshore wind farm convergence system compression sensing ranging equation fault location
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部