Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

Modeling Conditional Yield Densities

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.     

Stochastic Technology, Risk Preferences, and Adoption of Site-Specific Technologies

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.     

Estimating Willingness to Pay for Improved Water Quality in the Presence of Item Nonresponse Bias

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.     

对《形状和位置公差》新标准的理解和应用

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。     

Price rigidities and institutional variations in markets with posted prices

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.     

我国现阶段剥削问题之解析

本文分析在我国现阶段生产力还不发达的特殊历史条件下,剥削问题产生的原因、剥削现象存在的历史必然性,以及如何正确看待剥削现象中的积极因素等问题,力图科学、合理地厘清现阶段剥削之含义并阐明其与阶级剥削的本质区别。     

浅谈我国超细碳酸钙生产技术现状及发展方向

文章提出“碳化工艺连续化、活化剂复合化、活化技术组合化、活化温度常温化、干燥技术组合化和系统工程化”,应成为我国超细碳酸钙生产技术未来发展的主要方向,并论述了我国目前超细碳酸钙生产技术的现状,用连续鼓泡碳化工艺来改造现有碳化工艺,并提出了超重力反应结晶法的完善办法。     

新巴塞尔协议对发展中国家资本流入的影响

2004年6月经过长达6年艰难国际谈判和三稿意见征询的新资本协议的出台，在国际金融领域引起广泛的关注和争议。本文把视角从金融界普遍关注的“新协议对银行金融风险监管的影响”转向“新协议对发展中国家资本流入的影响”。指出这部由发达国家倡导的风险协议在促进银行业风险管理的同时，也给包括我国在内的广大发展中国家的资本流入带来了不利影响，从而以一个新的角度对新巴塞尔协议的影响作出分析与评价。     

论知识经济学的一个重要基本原理——消费决定生产原理

一、马克思主义的“生产决定消费”原理模型与知识经济学的“消费决定生产”原理模型生产是社会再生产过程诸环节中的决定性环节,对交换、分配和消费各环节起主要的决定的作用,没有生产就没有交换、分配和消费;交换、分配和消费反过来又影响生产。这是马克思主义的一个基本原理