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991.
Biologists and conservation advocates have expressed grave concern over perceived threats to biological diversity. ``Biodiversity prospecting' – the search among naturally occurring organisms for new products of agricultural, industrial, and, particularly, pharmaceutical value – has been advanced as both a mechanism and a motive for conserving biological diversity. Economists and others have attempted to estimate the value of biodiversity for use in new pharmaceutical project research. In this paper we apply a new approach to estimating values: we employ two models of competition among differentiated products. Each model confirms previous findings that the value to private researchers of the ``marginal species' is likely to be small. The models can have very different implications with respect to social values, however. These findings underscore the need for a better understanding of the true meaning of diversity.Resources for the Future  相似文献   
992.
993.
This paper is concerned with the intertemporal welfare effects of production and export of products produced from a replenishable natural resource base. Myopic decisions are show to result in the competitive solution, because current users of the resource base do not calculate into current extraction and export decisions the long-run effects of depletion or accumulation caused by their collective action. With perfect information on the changing size of the resource base over time, truly optimal dynamic paths for production and consumption are derived by means of the Pontryagin Maximum Principle. The optimal and competitive paths, and resulting steady state equilibria are illustrated in both phase and in output space.  相似文献   
994.
The decline in the costs of communicating, coordinating, and collaborating across firms in the value chain has led to the emergence of new business models—virtually integrated companies, retail "bricks and clicks" organizations, and networks like AOL and eBay—that can be used by all kinds of companies to exploit new opportunities. With these new organizations comes a need for new governance practices—practices that permit swifter decisions, best practice sharing, and more focused operations.
The author argues that improvements in governance should focus on achieving the following:
  •  Organization structures that leverage external alliances while improving internal collaboration. This involves gaining acceptance of and support for a common aspiration across the company—the goal of deploying financial and human resources, complemented by technology, to build shareholder wealth.

      相似文献   
995.
The Narver and Slater (Narver, J.C., and Slater, S.F.: The Effect of Marketing Orientation on Business Profitability. Journal of Marketing 54 (1990): 20–35.) market orientation scale is tested in the context of the transition economies of central Europe and found to be both valid and reliable. Relationships between market orientation and both marketing strategy and performance broadly follow predictions from the Western literature indicating that the adoption of a market orientation is equally applicable in transition as in Western economies. A number of different approaches, however, are evident in the transition economies suggesting that other business orientations may coexist with a market orientation creating a richer and more complex set or organizational drivers.  相似文献   
996.
The goal of universal service has dominated the telecommunications policy landscape for at least the past half century. This policy objective has been promoted with cross subsidies from long-distance telecommunications services to subscribers to local telecommunications service. The economic rationale for these cross subsidies is network externalities. In this paper, we show that: (1) the presence of network externalities, even if substantial in overall magnitude, does not generally justify a subscribership subsidy, even a well-designed one; and (2) the empirical realities of telecommunications markets make it unlikely that subscribership subsidies of any kind will increase social welfare.  相似文献   
997.
A regulated upstream monopolist provides an input to firms in a downstream market. If the monopolist enters the downstream market, a natural concern is that it will act so as to raise its downstream rivals' costs. An offsetting incentive is that a higher downstream price will reduce demand for the input, which reduces the monopolist's profit. Conditions under which one incentive dominates the other are derived. The monopolist may desire to lower its downstream rivals' costs rather than raise them. These findings suggest that regulatory policy towards such downstream entry should not focus exclusively on the ability to discriminate.  相似文献   
998.
We use Demographic and Health Surveys (DHS) to compare “poverty” at two or more points in time within and between African countries. Our welfare measure is an index resulting from a factor analysis of various household characteristics, durables, and household heads’ education. An advantage of this measure is that for intertemporal and intraregional comparisons, we need not rely on suspect price deflators and currency conversion factors. The wide availability and similarity of questionnaires of the DHS facilitate comparisons over both time and countries. Our results generally show declines in poverty during the previous decade, largely due to improvements in rural areas.  相似文献   
999.
In this paper the validity of the monetary exchange rate model in the long run for the Canadian-U.S. dollar exchange rate is examined. The primary test employed is the Johansen (1991) and Johansen and Juselius (1990) cointegration technique. The effects of dummy variables and lag specification on the statistical inference are considered, and Monte Carlo simulations based on the estimated parameters are employed. Despite the use of the longest data set yet for the Canadian case, no evidence is found in favour of the monetary exchange rate model using the Johansen procedures. This result is confirmed by several other cointegration procedures. JEL Classification: F31; F41
La faillite du modèle monétaire du taux de change pour les dollars canadien et américain. Ce mémoire examine le modèle monétaire du taux de change pour savoir s'il est validé par l'expérience canado-américaine en longue période. Le test principal utilisé est la technique de cointégration de Johansen (1991) et Johansen et Juselius (1990). Les effets des variables fictives et de la spécification de la structure de délais sur l'inférence statistique sont considérés, et on utilise des simulations de Monte Carlo fondées sur les paramètres calibrés. Malgré le fait qu'on fait appel à la plus longue série chronologique utilisée dans ce type d'analyse à ce jour, on ne trouve aucun support du modèle monétaire du taux de change en utilisant les procédures de Johansen. Ce résultat est confirmé par l'utilisation de plusieurs autres procédures de cointégration.  相似文献   
1000.
A key question for Social Security reform is whether workers respond to the link on the margin between the Social Security taxes they pay and the Social Security benefits they will receive. We estimate the effects of the marginal Social Security benefits that accrue with additional earnings on three measures of labor supply: retirement age, hours, and labor earnings. We develop a new approach to identifying these incentive effects by exploiting five provisions in the Social Security benefit rules that generate discontinuities in marginal benefits or non-linearities in marginal benefits that converge to discontinuities as uncertainty about the future is resolved. We find that individuals approaching retirement (age 52 and older) respond to the Social Security tax-benefit link on the extensive margin of their labor supply decisions: we estimate that a 10% increase in the net-of-tax share reduces the two-year retirement hazard by a statistically significant 2.0 percentage points from a base rate of 15%. The evidence with regard to labor supply responses on the intensive margin is more mixed: we estimate that the elasticity of hours with respect to the net-of-tax share is 0.42 and statistically significant, but we do not find a statistically significant earnings elasticity. Though we lack statistical power to estimate results within subsamples precisely, the retirement response is driven mostly by the female subsample, while the hours response comes from the male subsample.  相似文献   
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