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81.
82.
Injection drug users (IDUs) transmit the human immunodeficiency virus (HIV) via both needle sharing and sex. Available interventions for this population have varying costs and effectiveness and focus on different risk behaviors. In this analysis, we look at two interventions. One is inexpensive, broad-based and provides modest risk reductions (street outreach (SO)); the other is narrowly focused, expensive and relatively effective (methadone maintenance). This analysis explores the effects of population risk behavior, intervention effectiveness, intervention costs, and decision constraints when allocating funds between these two interventions to maximize effectiveness. We develop a model of the spread of HIV, dividing IDUs into susceptibles (uninfected) and infectives, and separately portraying sex and injection risk. We simulate the epidemic in New York City for time periods from the mid-1980s to the early 1990s, and incorporate the behavioral effects of two interventions performed singly or in combination to find the allocation that maximizes the number of infections averted in the IDUs and their noninjecting sex partners, assuming interventions have increasing marginal costs. We find that the optimal allocation nearly always involves spending the maximum allowable amount on SO. This result is largely insensitive to variations in risk parameters, intervention efficacy, or cost. The model's structure, however, makes clear that many factors contribute to this insensitivity, namely the scope of the interventions, the dual drug/sex nature of HIV risk in the population, the asymmetry of sexual risk for men and women, and the potential benefits to nonIDUs. 相似文献
83.
YunTong Wang 《Review of Economic Design》2002,7(2):205-211
We consider the cost sharing problem with divisible demands of heterogeneous goods. We propose a cost sharing method called
Proportionally Adjusted Marginal Pricing (PAMP) method. PAMP is a nonadditive (in the cost function) extension of average cost pricing. We introduce an axiom called
Local Independence (LI) and use LI together with Continuity, Proportionality, and Scale Invariance to characterize PAMP.
Received: 23 March 2001 / Accepted: 16 November 2001
I thank Yves Sprumont, Hervé Moulin, and Ahmet Alkan for discussions, comments and suggestions. Thanks also go to the associate
editor and the referees, whose comments and suggestions greatly improve the paper. 相似文献
84.
R&D externalities can imply ranges of aggregate increasing returns to scale in R&D. As a consequence several equilibria can exist involving different numbers of firms and different R&D investment levels. In a theoretical model the equilibrium dynamics are analyzed, showing that cyclical fluctuations of the number of firms and R&D investment may be expected, and that the long-run equilibrium is highly sensitive to investors' initial beliefs. The model is tested empirically using a unique database comprising competing firms in various R&D races. 相似文献
85.
Growth in U.S. agriculture is linked to the non-farm economy through domestic terms of trade and factor market adjustments. With almost stable input growth, the relatively large contributions from growth in Total Factor Productivity (TFP) are passed on to intermediate and final consumers in the form of declining real prices for primary farm products. The resulting net growth in the real value of farm output (GDP) is relatively low (0.25% per annum). The decomposition of TFP suggests that public agricultural stock of knowledge and infrastructure are robustly associated with TFP growth, while spill-overs from private agricultural and economy wide research and development (R and D) are positive but, relatively small. 相似文献
86.
Joseph G. Rosse Deborah F. Crown Howard D. Feldman 《Employee Responsibilities and Rights Journal》1991,4(2):125-135
In the last few years bipartisan support for legalizing drugs has grown to a surprising level. Because of the lack of involvement of the business community in this debate, we surveyed the human resource managers of 127 firms about their perceptions of the effects of legalization. Their responses were uniformly negative, with expectations that drug use, absenteeism, worksite crime, and liability costs would increase, while the quality and quantity of work would decline. They also forecast increases in drug testing, performance monitoring, and education and rehabilitation programs as a result. 相似文献
87.
4D技术在工程项目管理中的应用和发展趋势 总被引:2,自引:0,他引:2
现代建设工程日趋复杂,传统的工程项目管理思想和手段已经无法满足项目业主越来越高的要求,进度、成本和质量管理彼此独立的传统模式导致许多弊端,主要表现在各专业生成的软件信息不能共享、项目参与各方所拥有的知识和经验不能很好地提供项目决策支持。随着管理思想、管理理论、IT技术的飞速发展,运用产品数据建模、软件集成(3D 成本/进度)的思想和方法,对传统管理工具进行变革成为可能。本文引进工程项目集成化管理思想,分析国内外4D技术研究的情况,提出4D建模技术辅助工程项目管理的发展方向和趋势。 相似文献
88.
89.
90.
We investigate the role of international trade and proximity to war in international stock markets during the invasion of Ukraine by employing DiD designs and panel data comprising 70 stock markets. We find that differences in trade exposure to warring countries (trade effect) have a substantial and negative impact on non-European equity markets but are irrelevant for European markets. In contrast, differences in the distance to warring countries (proximity effect) have a significant and negative impact on European markets but have no bearing on non-European markets. We find that the relevance of rent from mineral, natural gas, and oil resources and the relevance of metals, ores, and fuels in exports operate as mitigators of the trade effect. Our paper provides valuable empirical evidence regarding the importance of mitigating the vulnerability of financial markets to international trade when a major war breaks out. 相似文献