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1.
A generalized maximum entropy approach is adapted to empirically estimate crop-specific production technologies in Chinese agriculture. Despite a modest behavioral assumption about equal marginal returns of nonland inputs among crops, this method does not require price information, which is usually distorted in a centrally planned economy such as China. A multi-output technology for Chinese agriculture is estimated and input allocations for each province are recovered simultaneously. The estimated multi-output production technology and input allocations imply that China may have greater grain production potentials than previously thought.  相似文献   

2.
Searching an Ex Situ Collection of Wheat Genetic Resources   总被引:1,自引:0,他引:1  
A theoretical model is developed and applied to the search for disease and pest resistance in ex situ collections of wheat genetic resources, employing actual data on frequency distributions, disease losses, and search costs. Experiments developed from case studies clarify several misperceptions about the value of gene banks and their utilization by breeders. The observation that wheat breeders use gene banks rarely does not imply that marginal accessions have low value. High costs of transferring genes with conventional breeding techniques mean that it may be efficient to store certain categories of genetic resources (such as landraces) 'unused' for many years.  相似文献   

3.
Mathematical measures of entropy as defined by Shannon and cross entropy as defined by Kullback and Leibler are currently in vogue in the field of econometrics, primarily due to the comprehensive work of Golan, Judge, and Miller. An alternative interpretation of the entropy measure as a penalty function over deviations is presented, and a number of parallels are drawn with least squares estimators. It is demonstrated that both approaches may be applied to the general linear model. The causes of differences in estimated parameter values are described, and some suggestions for the formulation of entropy-based econometric problems are presented.  相似文献   

4.
Preference Uncertainty in Non-Market Valuation: A Fuzzy Approach   总被引:3,自引:0,他引:3  
In this article, we consider uncertain preferences for non-market goods, but we move away from a probabilistic representation of uncertainty and propose the use of fuzzy contingent valuation. We assume that a decision maker never fully knows her own utility function and we treat utility as a fuzzy number. The methodology is illustrated using data on forest valuation in Sweden. Fuzzy contingent valuation provides estimates of resource value in the form of a fuzzy number and includes estimates obtained using a standard probabilistic approach.  相似文献   

5.
This paper aims to estimate the non-market benefits derived from the potential development of a new urban park in the city of Thessaloniki (Greece). The city of Thessaloniki has up to now a very low rate of proportional green space per capita. On this context a large metropolitan park was announced, as part of a large-scale redevelopment project, but the final decision has not been made yet. In order to help policy makers to their final decision, an ex-ante valuation of the potential benefits of the park is carried out in this study. A contingent valuation survey was designed and implemented aiming to estimate the willingness to pay of local residents for the provision of this park, as well as to determine the spatial scale at which these values are assessed. The main finding of this study is that people living within 20 min from the reference site are willing to contribute a significant amount of money to support this project. Another interesting outcome is that the willingness to pay for this project was not considerably modified during a period of economic recession (2010–2013), which is mainly due to the growing public awareness of the importance of green spaces, as well as of the benefits of the planned park.  相似文献   

6.
重庆市耕地资源非市场价值估算   总被引:2,自引:0,他引:2  
研究目的:探讨耕地资源非市场价值内涵,估算重庆市耕地资源非市场价值。研究方法:运用生产成本法、影子价格法等估算方法,估算重庆市1997-2011年的耕地资源生态服务和社会服务非市场价值。研究结果:(1)重庆市单位面积内耕地资源生态服务价值和社会价值总体上呈波动上升趋势;(2)重庆市耕地资源生态服务价值中,营养循环功能价值、净化环境功能价值和大气调节功能价值上升幅度较大且所占比重较高;(3)重庆市耕地资源社会服务价值从高到低:基本生活保障价值(44.49%)>粮食安全功能价值(36.87%)>失业保障价值(18.63%),且基本生活保障价值呈下降趋势,粮食安全功能价值提升幅度较快;(4)农民作为耕地资源非市场价值体系的最基础价值主体,其价值需求尤其值得关注。研究结论:科学认识耕地生态和社会两大非市场价值,有利于耕地资源可持续利用。  相似文献   

7.
8.
The PMP methodology is extended to deal with many economic units, self-selection arising from heterogeneous economic behavior, and multiple limiting inputs. The novel structure for the analysis of this type of problems acquires the name symmetric positive equilibrium problem. This methodology is articulated in three phases that parallel those one of positive mathematical programming. The recovery of a cost function that calibrates the base-year decisions of each economic unit is realized within a maximum entropy framework. The methodology is illustrated by the analysis of a sample of Italian farms that operate under the complex policy mandates of the European Union.  相似文献   

9.
Initially used as a biological control against aphids, the Asian ladybird has become highly invasive in many regions, including Europe. While biological control is usually considered as an environmentally‐friendly alternative to chemical pesticides in controlling pests in crops, there is growing concern that these environmental benefits could be outweighed by the negative consequences of the invasion. These include (i) biodiversity losses as populations of native ladybirds suffer from intraguild predation and competition for resources; (ii) human nuisance in houses, including risks of allergy and (iii) potential losses to wine‐growers. We provide an economic valuation of environmental and private characteristics affected by the Asian ladybird's invasion. We conduct a discrete choice experiment among a representative sample of the French population. Our results show that the consequences of the Asian ladybird's introduction do affect significantly the population's welfare. Among these, the impact on biodiversity through the threat on native species appears to be a significant concern.  相似文献   

10.
Livestock diversity provides genetic alternatives that facilitate sustainable agricultural development. Despite this, animal genetic resources (AnGR) are being depleted at alarming rates. Subsidises available to production systems based on imported breeds are of several orders of magnitude greater than the costs of local breed conservation. Economic arguments for the conservation and sustainable use of threatened AnGR can be an effective means of establishing support for the development of appropriate enabling environments. Despite the importance of the economics of AnGR conservation, the subject has received limited attention. Reasons include: methodological difficulties inherent in valuing genetic resources; limited knowledge about appropriate analytical techniques; and lack of data regarding local breeds. As recent advances in economic valuation have eased methodological/analytical constraints, the issue of data availability has become critical. Data related to livestock keepers' preferences for different genetic resource attributes and the value placed on these across species, breeds and production systems are needed. Based on a study of a local pig breed in Mexico, this paper shows how the use of rural appraisal methods, in conjunction with recently developed analytical techniques, are capable of providing the data required for understanding the type and costs of interventions necessary to promote the conservation and sustainable use of AnGR.  相似文献   

11.
进行城市土地集约利用评价对加强城市土地集约利用与管理具有重要意义,结合广东省惠州市城市发展现状,从土地投入强度、土地使用强度、土地使用效益和土地生态环境4个方面选取12项指标构建惠州市城市土地集约利用综合评价指标体系,采用熵权—模糊综合评价模型对惠州市2009—2013年城市土地集约利用情况进行综合评价,研究结果表明:(1)2009—2013年惠州市城市土地集约利用水平呈现先下降再上升的波动状态,2012年的水平为近5年最低值;(2)2013年惠州市城市土地集约利用水平虽有所改善,但从整体看,研究时段内集约利用水平都处在"较低~中等"等级。惠州市应该努力转变城市土地管理和利用方式,积极探索"低投入,高产出"的土地集约利用模式,大力发展循环经济,逐步实现城市土地配置科学化、布局合理化、使用高效化,进一步提高城市土地集约利用水平。  相似文献   

12.
Food quality ratings can be used for product differentiation and strategic marketing. This article develops a differentiation measure based on the cross‐entropy of two distributions for speciality coffees. It examines whether quality ratings achieve their objectives for speciality coffee supply chains. The estimation, using e‐auctions data, indicates that the quality rating is more informative in the Cup of Excellence (CofE) relative to the Q auction. To determine significance, a statistical test for comparing the information measure across different e‐auctions and segments of the quality rating was developed. The significant difference between the two auctions is not a surprise as the auctions trade coffee lots of different volumes and the quality evaluation is more important in the case of the CofE, with its jury of renowned coffee experts. The total cross‐entropy measure of product differentiation shows that the 100‐point quality rating does not carry the same information content and meaning in the two different e‐auctions and their respective supply chains. The cross‐entropy measure of product differentiation is shown to be a good indicator of the information and the value created throughout the speciality food supply chain.  相似文献   

13.
We employ a discrete choice experiment to elicit demand and supply side preferences for insurance‐linked credit, a promising market‐based tool for managing agricultural weather risks and providing access to credit for farmers. We estimate preference heterogeneity using primary data from smallholder farmers and managers of lenders/insurers combined with household socio‐economic survey data in Kenya. We analyse the choice data using maximum simulated likelihood and Hierarchical Bayes estimation of a mixed logit model. Although there are some similarities, we find that there is conflicting demand and supply side preferences for credit terms, collateral requirements, and loan use flexibility. We also analyse willingness to buy and willingness to offer for farmers and suppliers, respectively, for the risk premium for different attributes and their levels. Identifying the preferred attributes and levels for both farmers and financial institutions can guide optimal packaging of insurance and credit providing market participation and adoption motivation for insurance‐bundled credit product.  相似文献   

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