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.     

论我国高等教育产业化的可能途径

笔者通过探讨推动我国高等教育产业化的可能途径以及当前所要解决的问题,并就我国高等教育产业化的发展前景进行了较系统的分析,认为我国高等教育走产业化之路是一种客观必然趋势。     

中欧合作助力北京环境产业建设——环保节能与国际合作研讨会在京举行

“左祖右社，前朝后市，万贾云集，人文荟萃”。在马可波罗游记中，北京“举世莫能与比”。日前，为加强社会与政府在城市环境建设及节能环保产业发展上的交流与沟通，进一步推进北京与欧洲节能环保产业的技术交流与企业合作，投资北京国际有限公司联合芬兰贸易技术中心、中国丹麦商会、中国瑞典商会、德国工商总会北京代表处共同发起了“环保节能与国际合作研讨会”，研讨会由《投资北京》杂志社承办。会议于8月22日在北京新城国际亚地里亚举行，投资北京国际有限公司董事长屠行健主持会议并致辞，来自国内外的知名环保企业家，权威专家学者，政府官员及媒体记者50余人参加了本次研讨会。[编者按]     

德国如何成功举办世界杯足球赛

2006年德国世界杯足球赛是2008年北京奥运会之前全球最大的体育赛事。北京市发改委奥运经济高级顾问黄为专程前往德国，为北京奥运求取真经。[编者按]     

西气东输工程用感应加热弯管技术条件探讨

在对国外X70管线弯管技术条件进行调查分析与研究的基础上，对其中的几个关键技术问题包括母管成分，弯管的制造工艺和技术路线，强度与韧性要求，屈强比，Cu污染问题等进行了讨论。一些观点在西气东输感应加弯管技术条件中得到应用。     

一种新型电磁式导引器

介绍一种以负阻抗L－C振荡为基本环节的电磁式导引器，分析了其工作原理，给出了实验线路框图及位移特性。