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Characterization of Small-Scale Farmers and Assessment of Their Access to Crop Production Information in Selected Counties of Kenya
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作者 Anastasia Mumbi Wahome John B. K. Kiema +1 位作者 Galcano C. Mulaku Isaac Mukoko 《Agricultural Sciences》 2024年第5期565-589,共25页
Small-scale farming accounts for 78% of total agricultural production in Kenya and contributes to 23.5% of the country’s GDP. Their crop production activities are mostly rainfed subsistence with any surplus being sol... Small-scale farming accounts for 78% of total agricultural production in Kenya and contributes to 23.5% of the country’s GDP. Their crop production activities are mostly rainfed subsistence with any surplus being sold to bring in some income. Timely decisions on farm practices such as farm preparation and planting are critical determinants of the seasonal outcomes. In Kenya, most small-scale farmers have no reliable source of information that would help them make timely and accurate decisions. County governments have extension officers who are mandated with giving farmers advisory services to farmers but they are not able to reach most farmers due to facilitation constraints. The mode and format of sharing information is also critical since it’s important to ensure that it’s timely, well-understood and usable. This study sought to assess access to geospatial derived and other crop production information by farmers in four selected counties of Kenya. Specific objectives were to determine the profile of small-scale farmers in terms of age, education and farm size;to determine the type of information that is made available to them by County and Sub-County extension officers including the format and mode of provision;and to determine if the information provided was useful in terms of accuracy, timeliness and adequacy. The results indicated that over 80% of the farmers were over 35 years of age and over 56% were male. Majority had attained primary education (34%) or secondary education (29%) and most farmers in all the counties grew maize (71%). Notably, fellow farmers were a source of information (71%) with the frequency of sharing information being mostly seasonal (37%) and when information was available (43%). Over 66% of interviewed farmers indicating that they faced challenges while using provided information. The results from the study are insightful and helpful in determining effective ways of providing farmers with useful information to ensure maximum benefits. 展开更多
关键词 Small scale Farmers FARMERS Crop production Information Services Geospatial Information Information Access
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Dendritic cells derived from pluripotent stem cells:Potential of large scale production 被引量:5
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作者 Yan Li Meimei Liu Shang-Tian Yang 《World Journal of Stem Cells》 SCIE CAS 2014年第1期1-10,共10页
Human pluripotent stem cells(hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are promising sources for hematopoietic cells due to their unlimited growth capacity and the pluripot... Human pluripotent stem cells(hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are promising sources for hematopoietic cells due to their unlimited growth capacity and the pluripotency. Dendritic cells(DCs), the unique immune cells in the hematopoietic system, can be loaded with tumor specific antigen and used as vaccine for cancer immunotherapy. While autologous DCs from peripheral blood are limited in cell number, hPSC-derived DCs provide a novel alternative cell source which has the potential for large scale production. This review summarizes recent advances in differentiating hPSCs to DCs through the intermediate stage of hematopoietic stem cells. Step-wise growth factor induction has been used to derive DCs from hPSCs either in suspension cultureof embryoid bodies(EBs) or in co-culture with stromal cells. To fulfill the clinical potential of the DCs derived from hPSCs, the bioprocess needs to be scaled up to produce a large number of cells economically under tight quality control. This requires the development of novel bioreactor systems combining guided EB-based differentiation with engineered culture environment. Hence, recent progress in using bioreactors for hPSC lineage-specific differentiation is reviewed. In particular, the potential scale up strategies for the multistage DC differentiation and the effect of shear stress on hPSC differentiation in bioreactors are discussed in detail. 展开更多
关键词 PLURIPOTENT stem CELLS DENDRITIC CELLS BIOREACTOR HEMATOPOIETIC differentiation Large scale production
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Multidisciplinary design optimization on production scale of underground metal mine 被引量:4
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作者 左红艳 罗周全 +1 位作者 管佳林 王益伟 《Journal of Central South University》 SCIE EI CAS 2013年第5期1332-1340,共9页
In order to ensure overall optimization of the underground metal mine production scale, multidisciplinary design optimization model of production scale which covers the subsystem objective function of income of produc... In order to ensure overall optimization of the underground metal mine production scale, multidisciplinary design optimization model of production scale which covers the subsystem objective function of income of production, safety and environmental impact in the underground metal mine was established by using multidisciplinary design optimization method. The coupling effects from various disciplines were fully considered, and adaptive mutative scale chaos immunization optimization algorithm was adopted to solve multidisciplinary design optimization model of underground metal mine production scale. Practical results show that multidisciplinary design optimization on production scale of an underground lead and zinc mine reflect the actual operating conditions more realistically, the production scale is about 1.25 Mt/a (Lead and zinc metal content of 160 000 t/a), the economic life is approximately 14 a, corresponding coefficient of production profits can be increased to 15.13%, safety factor can be increased to 5.4% and environmental impact coefficient can be reduced by 9.52%. 展开更多
关键词 多学科设计优化 地下金属矿山 生产规模 免疫优化算法 优化模型 环境影响 安全系数 铅锌矿
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An intelligent system for calculating the scale of rational,enlarged production of an underground non-ferrous metal mine 被引量:4
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作者 ZHENG Ming-gui CAI Si-jing 《Journal of China University of Mining and Technology》 EI 2008年第2期214-219,共6页
The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of ar... The enlarged production scale of underground non-ferrous metal mines is affected by many uncertain factors difficult to describe mathematically with any level of accuracy.The problem can be solved by a synthesis of artificial intelligence.Based on the analysis of the major factors affecting the scale of enlarged production,we first interpreted in detail the design principles and structure of the intelligent system.Secondly,we introduced an ANN subsystem.In order to ensure technological and scale efficien- cies of the training samples for ANN,we filtrated the samples with a DEA method.Finally,we trained the intelligent system,which was proved to be very efficient. 展开更多
关键词 非铁金属矿山 生产范围 智能系统 ANN
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An Empirical Study on the Moderate Scale of Food-production-based Family Farm in Guangxi
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作者 Yaogui WU 《Asian Agricultural Research》 2016年第4期22-24,共3页
The moderate scale family farm is the future agricultural business entity in China,and the scale of family farm is a key factor affecting its development.With Guigang City in Guangxi as a point for the study,from the ... The moderate scale family farm is the future agricultural business entity in China,and the scale of family farm is a key factor affecting its development.With Guigang City in Guangxi as a point for the study,from the perspective of maximizing income of rural households,this paper uses production function model to calculate the moderate scale of food-production-based family farm at 5.7 ha,and makes policy recommendations. 展开更多
关键词 FOOD production Family FARM MODERATE scale
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Effects of the Produced Water from a Sour Oilfield in South Kuwait on the Production Tubing
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作者 Feras Al Salem Vijo Poulose +3 位作者 Kazuyuki Kawamura Arata Nakamura Hakim Saibi Thies Thiemann 《Journal of Water Resource and Protection》 2023年第7期358-375,共18页
Kuwaiti oil production faces a growing challenge in the increasing quantities of produced water generated in the production of oil. The high water cut of the produced fluid from the wells and the high salinity of the ... Kuwaiti oil production faces a growing challenge in the increasing quantities of produced water generated in the production of oil. The high water cut of the produced fluid from the wells and the high salinity of the produced water lead to significant degradation of subsurface equipment, specifically the production tubing. Debris generated through the degradation of the inner part of the tubing becomes a constituent of the scaling that deposits in the tubing and blocks the flow of the production fluid, inducing higher maintenance costs. This paper looks at the characteristics of the scaling in regard to the produced water and outlines the economic impact of the produced water induced degradation of the tubing structure. 展开更多
关键词 Produced Water SCALING production Tubing Corrosion SEM-EDS WD-XRF XPS
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Study on the Production Benefit of Large-scale Tobacco Growers
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作者 Shunyou LU Qinggao CHEN +2 位作者 Ting LEI Yuanhui WANG Huizhong LIU 《Asian Agricultural Research》 2014年第5期8-10,共3页
The tobacco growers with the growing area of greater than or equal to 100 mu,have become an important subject of tobacco production in Weng'an County of Guizhou Province. Regulating and developing the production a... The tobacco growers with the growing area of greater than or equal to 100 mu,have become an important subject of tobacco production in Weng'an County of Guizhou Province. Regulating and developing the production and business activities of large-scale tobacco growers, plays an important role in stabilizing tobacco production,reducing costs and increasing efficiency in Weng'an County. Through the field survey of large-scale growers' production activities,this article analyzes the input and output levels,and explores the key factors influencing benefit, in order to provide a basis for further regulating the tobacco growing practices and improving the flue-cured tobacco production benefit. 展开更多
关键词 LARGE-scale TOBACCO GROWERS production BENEFIT KEY
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Impact of Small-scale Production Mode on Citrus Industry of Hunan Province,China——Based on the Investigation on Citrus Industry in Shimen County
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作者 HU Zhi-dan1,WANG Kui-wu2,BO Xin1,TAN Jie2 1.College of Humanities,Hunan Agricultural University,Changsha 410128,China 2.Department of Scientific Research,Hunan Agricultural University,Changsha 410128,China 《Asian Agricultural Research》 2010年第3期38-40,共3页
Small-scale farmer is defined by the domestic and foreign experts and scholars.They point out that since the fragmentation of production and the diseconomy of scale in small-scale farmer is inconsistent with the chara... Small-scale farmer is defined by the domestic and foreign experts and scholars.They point out that since the fragmentation of production and the diseconomy of scale in small-scale farmer is inconsistent with the characteristics of scale and technology of modern agricultural production,it is necessary to eliminate the adverse effects of existing mode in order to provide theoretical references for the relevant researches.Citrus industry in Shimen County,Hunan Province,China is introduced from the aspects of natural geographical condition and socio-economic benefit.Impact of small-scale production mode on citrus production in Shimen County is discussed.Firstly,blindness of small-scale production is the main reason leading to overproduction of citrus.Secondly,small-scale production mode has limitation on the acceptance of new technologies,restricts the operation of geographical trademark,and constraints the enthusiasm of enterprises in entering the agricultural field.Finally,suggestions are put forward,such as encouraging the circulation of rural land,improving the organization degree of farmers,changing the work function of grass-roots government and perfecting the agricultural financial credit system. 展开更多
关键词 SMALL-scale production MODE CITRUS INDUSTRY Geogra
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Sustainable Potato Production in the Mountain Area of Ecuador, an Approach to Increase Productivity with Small Scale Farmers
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作者 Alicia Villavicencio Chang Hwan Park +16 位作者 Kangjin Cho Rona Bae Diego Peñ aherrera Gabriela Narváez Victoria López José Camacho Jovanny Suquillo Fausto Yumisaca Cesar Asaquibay María Nieto David Ortega Verónica Quimbiamba Cristian Torres Edwin Naranjo Stalin Cuenca Ricardo Alvarez 《Agricultural Sciences》 CAS 2022年第10期1080-1090,共11页
Ecuador potato crop is family based production system. Potato production has two roles in their economy, the first is providing food for their families and the second is a source of income for the household. However s... Ecuador potato crop is family based production system. Potato production has two roles in their economy, the first is providing food for their families and the second is a source of income for the household. However small scale farmers have limited access to local markets and most of the sales are through intermediates’ who purchase directly in the field at the lowest price possible. Potato production challenges for the small-scale farmers are among others availability of quality potato seed, direct sales, purchase of agrochemical inputs to maintain their crops and lack of education. In 2021, only 4% of potato farmers used certified seed. Potato yield is still low around 16.1 t&#183;ha<sup>-1</sup>, in the last 10 years the total potato cultivated area was reduced by at least 50%. The farmers produce “Bokashi” and other organic fertilizer and these are effective to improve soil fertility and plant health. Homemade bio-pesticides reduce agrochemical pesticides. The Decision Support System (DSS) is a handheld device to control late blight, minimizes fungicide applications and improve fungicide rotation. In 2018 Candidatus Liberibacter solanacearum (Lso), the causal agent of zebra chip, and its vector, the potato psyllid Bactericera cockerelli, together created havoc for farmers and researchers. Promotion of early potato varieties INIAP—Libertad is an alternative to lower the impact of this newest pest. 展开更多
关键词 POTATO Yield Small-scale Farmers Agro-Ecological production Quality Seed
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Kenyan Counties Geospatial Data Knowledge to Monitor Crop Production
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作者 Anastasia Mumbi Wahome John B. K. Kiema Galcano C. Mulaku 《Journal of Geographic Information System》 2023年第6期629-651,共23页
Climate change effects have had negative effects on most farmers, both small and large-scale, with weather patterns increasingly becoming unpredictable, such that farmers are unable to plan well for their farming, res... Climate change effects have had negative effects on most farmers, both small and large-scale, with weather patterns increasingly becoming unpredictable, such that farmers are unable to plan well for their farming, resulting in reduced harvests and sometimes losses for farmers. Better availability of information such as weather patterns, suitable crops, nutrient requirements based on soil types and conditions would greatly alleviate these challenges. While geospatial information is being developed and improved continuously by researchers, its accessibility and use by the counties has not been established and cannot be identified as contributing to better crop production outcomes. The aim of this study, therefore, was to assess the awareness and status of geospatial data availability and use for crop production, and the level of the relevant capacities, both human and infrastructural, in selected Counties of Kenya. A survey was conducted in the four counties of Vihiga, Kilifi, Wajir and Nyeri and key informant interviews were conducted with both management and technical County Agricultural Officers, as well as sub-county agricultural extension officers. From the results of the survey, out of the four counties, only one has adequate infrastructure in terms of hard-ware, software and connectivity to conduct useful geospatial data acquisition and processing. While most indicated awareness of the existence of geospatial data, limited resources, low skills and knowledge have restricted any meaningful sourcing of and access to data, with only 38% moderately or highly skilled in acquisition, 48% in processing and 57% in interpretation and use of geospatial data. The study concludes that moderate skills and capacities available within the counties have considerable potential to make use the available geospatial data to inform farmers accordingly and improve their farming outcomes. 展开更多
关键词 Geospatial Data Crop production AGRICULTURE FARMERS Small-scale Farmers
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我国肉羊养殖生产全程机械化现状及发展建议
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作者 谭秀文 崔绪奎 +3 位作者 金海 王可 刘昭华 孟宪锋 《中国农机化学报》 北大核心 2024年第4期51-57,共7页
通过国家肉羊产业技术体系、地方畜牧主管部门等组织,对全国13个省市、自治区的113家规模化羊场全程机械化养殖情况进行调研,结果存(出)栏羊规模1万只以上的有20家,占比17.70%,其中3万只以上大型养羊企业8家,仅占7.08%;中小规模羊场(5 ... 通过国家肉羊产业技术体系、地方畜牧主管部门等组织,对全国13个省市、自治区的113家规模化羊场全程机械化养殖情况进行调研,结果存(出)栏羊规模1万只以上的有20家,占比17.70%,其中3万只以上大型养羊企业8家,仅占7.08%;中小规模羊场(5 000只以下)75家,占比66.37%。按照羊场养殖规模分别对饲草料加工、饲喂、饮水、清粪、消毒、装卸羊等各生产环节机械化水平进行统计分析,自动化饮水占比最高为63.9%,其次为机械化清粪(62.9%)、消毒机械化(42.4%)和TMR饲喂(41.3%),舍内有害气体检测占比最低,仅为8.3%。养殖各生产环节机械化水平随着养殖规模的扩大而提高。影响养殖各生产环节机械化水平的因素主要是肉羊生产本身效率和效益较低,标准化、产业化生产水平低等,表现在不同地域、不同养殖环节机械化水平差异大,肉羊机械装备基础研究薄弱、科技创新能力差,产品标准化程度低,售后维修配套服务差等,建议加强宣传和示范推广工作,加强行业监管,逐步建立与养殖机械化发展水平相适应的监督服务体系,加大基础研究,增强科技创新能力,研究制定相关行业标准,推动行业标准化生产。 展开更多
关键词 肉羊 养殖机械化 规模化 生产效益 行业标准
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城市创新创业活力与新兴产业核心技术:空间极化、规模门槛与中介效应 被引量:1
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作者 刘承良 刘向杰 《中国软科学》 CSCD 北大核心 2024年第3期212-224,共13页
城市新企业、新资本和新发明涌现是孕育新兴产业核心技术的活力源泉,对加快形成新质生产力具有重要意义。利用中国城市面板数据考察创新创业活力对新兴产业核心技术的影响及作用机制。研究发现:(1)城市创新创业活力显著促进新兴产业核... 城市新企业、新资本和新发明涌现是孕育新兴产业核心技术的活力源泉,对加快形成新质生产力具有重要意义。利用中国城市面板数据考察创新创业活力对新兴产业核心技术的影响及作用机制。研究发现:(1)城市创新创业活力显著促进新兴产业核心技术数量提升,在考虑一系列稳健性检验后结论仍然成立。(2)创新创业活力对新兴产业核心技术活动的影响存在“边际递增”的城市规模门槛特征,而对邻近城市产生显著的抑制作用,存在“马太效应”和“虹吸效应”。(3)城市创新创业活力对新兴产业核心技术活动的影响存在区域和梯度异质性,不同地理位置和文化区的城市存在显著差异,而资源型城市、智慧城市和创新型城市的分组回归体现了梯度性特征。(4)创新创业活力通过提升城市多样性,特别是专业化部门的多样性程度,促进新兴产业核心技术数量增长。 展开更多
关键词 新兴产业核心技术 新质生产力 创新创业活力 城市多样性 城市规模
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离子交换树脂法规模化生产乳源酪蛋白糖巨肽及其对流感病毒的血凝抑制活性
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作者 汪清美 刘小雨 +2 位作者 陈庆森 赵培 闫亚丽 《食品与机械》 CSCD 北大核心 2024年第5期194-202,共9页
目的:优化规模化生产乳源酪蛋白糖巨肽(CGMP)的工艺条件,并探讨其对流感病毒的血凝抑制能力。方法:以阴离子交换树脂为分离介质,唾液酸含量为产品的活性检测指标,分别从上样体积、上样流量、洗脱液浓度、洗脱液体积和树脂使用周期5个工... 目的:优化规模化生产乳源酪蛋白糖巨肽(CGMP)的工艺条件,并探讨其对流感病毒的血凝抑制能力。方法:以阴离子交换树脂为分离介质,唾液酸含量为产品的活性检测指标,分别从上样体积、上样流量、洗脱液浓度、洗脱液体积和树脂使用周期5个工艺条件,在前期小试和中试的基础上,考察从乳清粉中规模化生产CGMP;同时利用血球凝集抑制试验验证产品CGMP对流感病毒的抑制活性。结果:优化的CGMP产品技术路线为上样体积3BV、上样流量0.8 L/min、洗脱体积1BV、洗脱液浓度0.6 mol/L、树脂适宜使用周期4次。该工艺条件下处理乳清粉溶液体积为108 L(2160 g)、树脂36 L,得到CGMP产品21.183 g,得率为0.981 g/100 g,产品纯度为89.032%,回收率为51.972%,唾液酸含量为21.503 g/100 g,蛋白CGMP产品对流感病毒A(H1N1)和流感病毒B的最低抑制质量浓度分别为1.0000,1.2500 mg/mL。结论:利用优化的技术路线生产获得CGMP产品的纯度和唾液酸含量均优于市售商品CGMP,且对流感病毒有明显的抑制作用。 展开更多
关键词 酪蛋白糖巨肽 规模化生产 阴离子交换树脂 工艺优化 唾液酸 流感病毒 血球凝集抑制
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中药饮片产业发展现状及供给侧问题与对策
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作者 郁红礼 李林 +8 位作者 金传山 杜伟峰 马恩耀 张伟 季德 张兴德 彭瑞潭 申诺 陆兔林 《中国现代中药》 CAS 2024年第3期439-446,共8页
分析了中药饮片产业及市场规模现状,相关法律、法规、政策等,从供给侧剖析产业发展瓶颈,解析中药饮片生产标准化、规模化程度低,技术及产品创新不足,缺少协调供需平衡的宏观统筹问题,提出加强炮制理论基础研究、提高中药饮片生产标准化... 分析了中药饮片产业及市场规模现状,相关法律、法规、政策等,从供给侧剖析产业发展瓶颈,解析中药饮片生产标准化、规模化程度低,技术及产品创新不足,缺少协调供需平衡的宏观统筹问题,提出加强炮制理论基础研究、提高中药饮片生产标准化水平的对策措施,包括提高中药炮制技术的标准化水平、完善质量控制标准、建立等级标准等,倡导提高产业规模化水平、实施大品种战略、鼓励科技创新、组建创新联合体,加快中药饮片数字化、智能化生产管理研发及新产品研发,并从调控供需平衡角度提出了推进中药饮片区域化生产与流通的措施等,以期构建以高品质中药饮片为核心的创新型产业发展格局,探寻振兴中药饮片产业高质量发展之路。 展开更多
关键词 中药饮片产业 发展现状 标准化 规模化 供需平衡 创新生产
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我国青贮玉米生产的集聚演变及其作用机制——基于动态空间杜宾模型
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作者 颜姣姣 罗国庆 张翼 《饲料研究》 CAS 北大核心 2024年第1期175-180,共6页
为观测青贮玉米生产的动态变化,研究基于2001—2021年我国30个省面板数据,选用重心模型分析青贮玉米生产集聚区域变动。在此基础上,借助动态空间杜宾模型剖析要素投入、社会经济、政策支持对中国青贮玉米生产区域变动的影响。结果表明,... 为观测青贮玉米生产的动态变化,研究基于2001—2021年我国30个省面板数据,选用重心模型分析青贮玉米生产集聚区域变动。在此基础上,借助动态空间杜宾模型剖析要素投入、社会经济、政策支持对中国青贮玉米生产区域变动的影响。结果表明,我国青贮玉米存在空间聚集现象,即2001—2021年间我国青贮玉米生产量的莫兰指数总体上呈“先降再升再降再升”的发展态势。生产重心演变轨迹结果显示,我国青贮玉米生产区域重心呈现“先东北后西北、西南”的演变趋势。机制结果表明,粮食优势、财政扶持、务工收入增加是推进青贮玉米生产的主要驱动因素;生产基础设备、化肥施用、农业收益对本省份青贮玉米生产具有正向影响,但对相邻省份青贮玉米生产的影响不显著。 展开更多
关键词 青贮玉米 生产规模 重心演变轨迹 动态空间杜宾模型
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2001-2020年内蒙古净生态系统生产力格局多时间尺度分析
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作者 翟涌光 王晓妮 +5 位作者 郝蕾 戚文超 王雅崧 耿佳玉 兰穹穹 王志国 《生态环境学报》 CSCD 北大核心 2024年第2期167-179,共13页
掌握净生态系统生产力(NEP)时空格局对提高干旱/半干旱地区生态系统功能有重要意义。已有的NEP时空格局研究大多以年尺度开展分析,而NEP在多时间尺度上的特征差异尚不明晰。基于多源遥感、气象和地面实测数据,采用CASA模型、土壤呼吸地... 掌握净生态系统生产力(NEP)时空格局对提高干旱/半干旱地区生态系统功能有重要意义。已有的NEP时空格局研究大多以年尺度开展分析,而NEP在多时间尺度上的特征差异尚不明晰。基于多源遥感、气象和地面实测数据,采用CASA模型、土壤呼吸地质统计模型(GSMSR)和土壤呼吸-土壤异养呼吸(Rs-Rh)关系模型耦合模拟内蒙古2001-2020年NEP,分析其年、季、月多时间尺度时空特征,并探讨8种不同植被NEP的多时间尺度特征差异。结果表明,1)内蒙古年尺度NEP的空间分布格局稳定,从东北向西南递减,这一格局与春夏秋3季及植被生长期的3-10月一致,而冬季植被进入休眠期使得空间差异显著减小。2)内蒙古多时间尺度NEP年际变化趋势有所不同:年尺度上,内蒙古总NEP呈波动上升趋势,年际变化率为C 3.75 Tg·a^(-1);季尺度上,夏季增长趋势最大,占全年增长的41.6%,春秋两季对NEP的增长也起到至关重要的作用,分别占比34.9%和23.3%,冬季对NEP增长贡献非常有限;月尺度上,NEP年内变化与植被生长物候周期较为接近,1月和12月年际NEP为减少趋势,其余月份年际NEP均为上升趋势,其中9月增长趋势最大,占全年增长的19.3%。3)不同植被类型NEP年际趋势存在差异,5种植被类型年NEP呈增长趋势,3种呈下降趋势;草地在季尺度年际变化中均保持增长,在夏季最高,而灌木林在季尺度年际变化中均为降低趋势,夏季降幅最大;月尺度年际变化中灌木林均为降低趋势,1月降幅最大。该研究能够为明晰区域碳循环及改善生态系统功能提供科学依据。 展开更多
关键词 净生态系统生产力 多时间尺度 分布格局 CASA模型 GSMSR模型 内蒙古
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多向加权Tsallis熵最大化导向的自动阈值分割方法
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作者 邹耀斌 邓世成 +3 位作者 孟祥丹 周欢 孙水发 陈鹏 《电子学报》 EI CAS CSCD 北大核心 2024年第1期129-143,共15页
受噪声或随机细节、目标和背景的大小比例、成像时的点扩散等不同因素的影响,许多图像的灰度直方图呈现为无模态、单模态、双模态或者多模态样式.为了在统一框架内处理这4种不同模态情形下的自动阈值选择问题,本文提出了一种多向加权Tsa... 受噪声或随机细节、目标和背景的大小比例、成像时的点扩散等不同因素的影响,许多图像的灰度直方图呈现为无模态、单模态、双模态或者多模态样式.为了在统一框架内处理这4种不同模态情形下的自动阈值选择问题,本文提出了一种多向加权Tsallis熵最大化导向的自动阈值分割方法(Multi-directional Weighted Tsallis Entropy,MWTE).基于新设计的反正切方向性卷积核的多尺度乘积效应,该方法将不同模态的灰度直方图转化为统一的单模态右偏灰度直方图.在4个不同方向上提取出这种特殊的单模态右偏灰度直方图后,通过多向加权策略构建出与原始图像灰度值紧密相关的加权Tsallis熵目标函数,并以该目标函数取最大值时对应的灰度值作为最终分割阈值.本文将提出的方法和3个阈值分割方法、1个软分割方法、1个活动轮廓分割方法以及1个自动聚类分割方法进行了比较.在4种不同模态情形下的4幅合成图像和50幅真实世界图像上的实验结果表明,本文提出的方法虽然在计算效率方面不占有优势,但它对不同模态的测试图像具有更稳健的分割适应性,且在量化分割精度所用的马修斯相关系数方面优于其他6个分割方法. 展开更多
关键词 阈值分割 Tsallis熵差 加权Tsallis熵 反正切方向性卷积核 多尺度乘积效应 马修斯相关系数
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农业保险、农业规模化经营与农业绿色生产
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作者 郑军 武翠萍 《贵州大学学报(社会科学版)》 2024年第3期22-29,共8页
为探讨农业保险、农业规模化经营与农业绿色生产之间的关系,本文首先构建一个包含农业保险、农业规模化经营与农业绿色生产的C-D生产函数与理论分析框架,系统分析农业保险推动农业规模化经营从而实现农业绿色生产的作用机制;其次基于200... 为探讨农业保险、农业规模化经营与农业绿色生产之间的关系,本文首先构建一个包含农业保险、农业规模化经营与农业绿色生产的C-D生产函数与理论分析框架,系统分析农业保险推动农业规模化经营从而实现农业绿色生产的作用机制;其次基于2007—2021年省级面板数据,采取混合回归与固定效应模型,实证考察农业保险的风险分散效应与农业规模化经营、技术效应与农业绿色生产的作用机制。研究表明:农业保险的政策性刺激农户参保,通过其保障性强化风险分散效应,推动农业规模化经营,并通过技术效应助推农业绿色生产。农业保险可以通过农业规模化经营助推农业绿色生产,因农业规模化经营中机械化水平不同农业保险对农业绿色生产的效果存在差异;进一步研究发现,相比于农作物种植面积多的地区,农业保险助推农业绿色生产的效果在农作物种植面积少的地区更好;在机械化水平高的地区,农业保险助推农业绿色生产效果更明显。 展开更多
关键词 农业保险 农业规模化经营 农业绿色生产
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考虑产水量变化的气井井筒结垢堵塞预测
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作者 陈怀兵 张耀刚 杨青松 《广州化工》 CAS 2024年第5期166-169,208,共5页
为提高气井解堵措施的针对性,综合考虑气井井筒无机物结垢的热力学和动力学影响,特别是考虑气井产水量变化与垢在井筒内壁的黏附系数,建立了气井井筒结垢堵塞预测模型,并应用于靖边气田。结果表明:基于平滑指数法预测了气井日产水量,预... 为提高气井解堵措施的针对性,综合考虑气井井筒无机物结垢的热力学和动力学影响,特别是考虑气井产水量变化与垢在井筒内壁的黏附系数,建立了气井井筒结垢堵塞预测模型,并应用于靖边气田。结果表明:基于平滑指数法预测了气井日产水量,预测时间越长,累积产水量的误差越小。加权系数α越小,预测结果越精准,模型中α取0.2;通过现场生产资料拟合,垢在井筒内壁的黏附系数取0.001时,能够取得较为满意的预测结果;现场应用结果表明该模型预测的结垢堵塞物组成和堵塞程度与现场相符,对气井井筒除垢解堵措施具有指导意义。 展开更多
关键词 结垢预测 气井井筒堵塞 日产水量预测 指数平滑法 堵塞率
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绿色生产背景下经营规模对农户技术效率的影响研究——基于福建省葡萄种植户的调查数据
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作者 宋芳 徐学荣 《黑龙江八一农垦大学学报》 2024年第2期113-120,共8页
基于当前农业绿色生产的重要发展背景,以福建省内六地市314个葡萄种植户的微观调查数据为支撑,运用面向投入规模报酬可变的DEA模型测度农户技术效率水平,并构建Tobit模型,实证避雨栽培的绿色生产模式下经营规模对农户技术效率的影响。... 基于当前农业绿色生产的重要发展背景,以福建省内六地市314个葡萄种植户的微观调查数据为支撑,运用面向投入规模报酬可变的DEA模型测度农户技术效率水平,并构建Tobit模型,实证避雨栽培的绿色生产模式下经营规模对农户技术效率的影响。结果表明:适度规模化经营有助于农户提高绿色生产的技术效率,葡萄种植面积的适度区间为0.67~3.33 hm^(2),但随着经营规模增加,要素配置难度和雇工道德风险上升将会给农户造成一定的效率损失。因此,农户在实际生产中应根据自身要素禀赋状况选择合适的经营规模,不宜盲目扩张。 展开更多
关键词 绿色生产 经营规模 技术效率 要素错配 道德风险
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