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61.
Modeling Conditional Yield Densities   总被引:2,自引:0,他引:2  
Given the increasing interest in agricultural risk, many have sought improved methods to characterize conditional crop-yield densities. While most have postulated the Beta as a flexible alternative to the Normal, others have chosen nonparametric methods. Unfortunately, yield data tends not to be sufficiently abundant to invalidate many reasonable parametric models. This is problematic because conclusions from economic analyses, which require estimated conditional yield densities, tend not to be invariant to the modeling assumption. We propose a semiparametric estimator that, because of its theoretical properties and our simulation results, enables one to empirically proceed with a higher degree of confidence.  相似文献   
62.
A model of farmer decision making is developed to determine the extent to which uncertainties about soil fertility and weather affect the value of site-specific technologies (SSTs) using jointly estimated risk and technology parameters. Uncertainty can lead risk-averse farmers to apply more fertilizers and generate more pollution than in the certainty case. Ignoring uncertainty and risk aversion would overestimate the economic and environmental benefits of SSTs and underestimate the subsidy required to induce adoption. Accounting for uncertainties and risk preferences might explain the low observed adoption rates of SSTs. Improving the accuracy of SSTs would increase the incentives for adoption.  相似文献   
63.
This article deals with the problem of item nonresponse in contingent valuation surveys using a payment-card method, by applying a grouped-data sample-selection estimation technique that is capable of imputing the missing values conditional upon a respondent's decision to answer a willingness-to-pay question. The advantage of the technique lies in its ability to utilize all of the information in the sample, permitting a more efficient estimation in the presence of item nonresponse bias. The major determinants of willingness to pay appear to be household income, number of children, education, perception of existing water quality, and identification with environmental issues.  相似文献   
64.
通过对《形状和位置公差》新、旧国际的对比,综述了新、旧标准间的不同之处、便于迅速了解和应用新标准。  相似文献   
65.
Summary Standard laboratory posted-offer markets respond slowly and incompletely to demand shocks. In these one-sided markets, where sellers control the setting of prices, very little information is transmitted via the process of exchange. For this reason, traders have trouble distinguishing randomness in their own experience from changes in market fundamentals. This paper reports the results of twelve laboratory markets conducted to assess whether some common variants to standard posted-offer rules can correct the adjustment deficiences. Although discounting, multiple postings and excess demand information all improve performance, we find that response remains poor, and efficiencies low.Support for this research was provided by the National Science Foundation (SBR 9319842 and SBR 9320044), and the University of Virginia Bankard Fund. Data are archived at FTP address: fido.econlab.arizona.edu. We wish to thank Charles Plott and Shyam Sunder for useful comments on an earlier draft of this paper. The usual disclaimer applies.  相似文献   
66.
工业文明在带给人类丰富的物质生活的同时,也使生态环境日益恶化.1987年,世界环境与发展委员会在<我们共同的未来>报告中第一次阐述了可持续发展的概念,即指经济、社会、资源和环境保护协调发展是一个密不可分的系统,既要达到发展经济的目的,又要保护好人类赖以生存的大气、淡水、海洋、土地和森林等自然资源和环境,使子孙后代能够永续发展和安居乐业.  相似文献   
67.
I.IntroductionSincethelate1990s,China’slabor market has comeundergreat pressure,asreflected by anincreasing unemployment rate,and adeclining labor force participation rate.The causesofthe severe unemployment are threefold.First,due to the macro-economic downturn andrapid industrial structural change in the late1990s,state-owned enterprises(SOEs),whichlost their comparative advantage and competitiveness,have been unable to fully utilizetheir production capacity,and have become loss-makers.Se…  相似文献   
68.
I.IntroductionDespite China’s impressive economic growth,its fiscal sustainability has increasinglybecome one of the most watched risk indicators facing the economy.Although China’sexplicit national debtto GDP ratio israther manageable by theOECD standard,at about20 percent of GDP,given its small share of tax revenue to GDP,currently at18.5percent ofGDP,this fiscalsystem may stumble upon major challenges in themedium to long term ifChina’slargecontingent fiscal liabilitiesare als…  相似文献   
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