我国房地产中介服务业的发展机遇和对策

本文阐述了住房新体制给房地产中介服务业带来的发展机遇,并分析了在该机遇下应采取的对策。目的在于建议政府部门对房地产中介服务业加以培育、规范和引导,以给该行业的发展营造较好的成长环境。同时,房地产中介服务业应把握机遇,努力提高自身素质,以促进城镇住房制度改革的进一步深化。     

试论我国企业并购的问题与对策

企业并购现巳成为我国企业界的热点,但在具体运作时还存在许多急需解决的问题。本文试对我国企业并购中的主要问题进行分析,并探讨相应的对策建议。     

认识中意会现象的研究

意会是认识中十分重要的现象，探讨了意会的含义，意会形成的机理，以及意会的重要意义。     

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.     

隋唐五代时期园艺作物的培育与引进

隋唐五代时期是我国园艺业发展史上的重要时期。多种园艺作物培育成功并有为数不少的域外作物引进中土。这些新品种的花果、蔬菜、香料等，为我国园艺业增添了新的内容，丰富了人民生活。有的作物后来传到国外，为世界园艺提供了宝贵的种质资源。培育与引进的成功，则是与隋唐五代时期经济发展、气候条件适宜以及园艺技术提高等因素紧密相关的。     

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.