美国以自然资源保护为宗旨的土地休耕经验

美国土地休耕制度包括一系列水土保持计划和以土壤侵蚀度为主要指标的水土保持评价标准,它通过一系列耕地保护计划来推行。回顾美国农业耕作土地采取休耕政策及其实施情况,讨论了值得我国学习和借鉴的土地休耕计划的政策的成本费用等问题。     

Perceived and actual option values of college enrollment

An important feature of postsecondary schooling is the experimentation that accompanies sequential decision making. Specifically, by entering college, a student gains the option to decide at a future time whether it is optimal to remain in college or to drop out, after resolving uncertainty that existed at entrance about factors that affect the return to college. This paper uses data from the Berea Panel Study to quantify the value of this option. The unique nature of the data allows us to make a distinction between “actual” option values and “perceived” option values and to examine the accuracy of students' perceptions.     

An overview of ethical and social issues in shared virtual environments

Shared virtual reality environments raise a number of ethical and social issues that have not so far received systematic attention. One reason is that virtual reality or shared virtual environments (SVEs) have not been clearly defined. This essay proposes that a strict definition of SVEs is necessary to be able to tackle these issues. It is also necessary, however, to put SVEs in the context of other new technologies and media—as well as identifying their unique features—in order to draw out their wider implications. The essay further argues that the discussion of ethical and social aspects of SVEs should be closely tied to current systems and uses, and it divides these into two groups: instrumental SVEs used mainly in research and as prototypes, and Internet-based SVEs for gaming and socializing. Different ethical and social considerations arise in relation to these two: guidelines for research and development for the former, and suggestions for appropriate and desirable uses for the latter. These two sides, it is argued, will increasingly overlap in the future, and the essay concludes with an outlook on the future development of SVEs.     

Liberty,equality, and efficiency J. E. Meade New York: New York university press, 1993, ix, 256 pp.

This is a review article of a book by J. E. Meade. The first part of the book is a reprint of a book published in 1964. This is not described. The remainder of the book, 164 pages, deals with a fictitious island-nation, Agathotopia, which is a good but not perfect place to live. The Agathotopian economy is based on a type of firm in which capitalists and laborers both hold shares which received equal dividends. Other matters described include taxes, the treatment of the environment, and the way in which Agathotopia might fit into an international union such as the European Community. The reviewer suggests that recent trends toward increased labor-management, profit sharing, and stock ownership plans may make the labor-capital partnership a serious alternative in the future.     

Residential spatial growth with perfect foresight and multiple income groups

This paper presents explicit solutions for expanding monocentric cities with two or more income groups. Housing is durable but deteriorates over time, and redevelopment cannot take place. Landlords have perfect foresight. The utility function and housing technology are Cobb-Douglas. Population, per capita income, and transportation costs per mile change at constant percentage rates. The model is solved analytically, using an infinite time horizon. As development proceeds outward, a constant fraction of land is developed with high-income housing, and the remaining land is reserved for future low-income development. At any time, housing is constructed at one distance for high-income consumers, and at a lesser distance for low-income consumers. High-income housing is first occupied by high-income consumers, then filters to low-income consumers, and is ultimately abandoned. Low-income housing is first occupied by low-income households, and ultimately abandoned.     

The gorbachev economic proposals and the U.S. economy

Invited address at the Twenty-Fourth Atlantic Economic Society Conference, September 3–5, 1987, New York, New York.     

Estimating the benefits of farm animal welfare legislation using the contingent valuation method

This paper presents the method and findings of a contingent valuation (CV) study that aimed to elicit United Kingdom citizens' willingness to pay to support legislation to phase out the use of battery cages for egg production in the European Union (EU). The method takes account of various biases associated with the CV technique, including ‘warm glow’, ‘part‐whole’ and sample response biases. Estimated mean willingness to pay to support the legislation is used to estimate the annual benefit of the legislation to UK citizens. This is compared with the estimated annual costs of the legislation over a 12‐year period, which allows for readjustment by the UK egg industry. The analysis shows that the estimated benefits of the legislation outweigh the costs. The study demonstrates that CV is a potentially useful technique for assessing the likely benefits associated with proposed legislation. However, estimates of CV studies must be treated with caution. It is important that they are derived from carefully designed surveys and that the willingness to pay estimation method allows for various biases.