少数人的可持续发展：绿色城市发展与居民住房支付能力探析

不少旨在改善旧城空间的棕地开发项目和重建项目,都将可持续发展列为明确的目标。然而问题的关键是,这些重建项目的好处是否公平地分配到原有的社会成员或者街坊手中,或者,是否以牺牲现有居民和商贩的利益和现有社区的多样性为代价,使新搬来的高收入住户获得更多好处？加拿大维多利亚市棕地开发的案例分析,为本文所探讨的由棕地开发引发的收入差异问题提供了例证。第二个案例研究了多伦多的社区,指出在已有的社区内进行可持续发展项目,并不能确保维持和鼓励现有的社会多样性和公平性。英属哥伦比亚省温哥华市Downtown Eastside的一系列填空性建设项目也证实了类似的趋势,即它们对周边社区产生了很大影响,而且事实上给可持续发展带来了反作用。因此,可持续发展与社区中产化及高档化之间的关系比我们想象的更加复杂。     

Human Interindividual Variability in Susceptibility to Airborne Particles

Part of the explanation for the persistent epidemiological findings of associations between mortality and morbidity with relatively modest ambient exposures to airborne particles may be that some people are much more susceptible to particle-induced responses than others. This study assembled a database of quantitative observations of interindividual variability in pharmacokinetic and pharmacodynamic parameters likely to affect particle response. The pharmacodynamic responses studied included data drawn from epidemiologic studies of doses of methacholine, flour dust, and other agents that induce acute changes in lung function. In general, the amount of interindividual variability in several of these pharmacodynamic response parameters was greater than the variability in pharmacokinetic (breathing rate, deposition, and clearance) parameters. Quantitatively the results indicated that human interindividual variability of breathing rates and major pharmacokinetic parameters-total deposition and tracheobronchial clearance-were in the region of Log(GSD) = 0.1 to 0.2 (corresponding to geometric standard deviations of 10(.1)-10(.2) or 1.26-1.58). Deposition to the deep lung (alveolar region) appeared to be somewhat more variable: Log(GSD) of about 0.3 (GSD of about 2). Among pharmacodynamic parameters, changes in FEV1 in response to ozone and metabisulfite (an agent that is said to act primarily on neural receptors in the lung) were in the region of Log(GSD) of 0.2 to 0.4. However, similar responses to methacholine, an agent that acts on smooth muscle, seemed to have still more variability (0.4 to somewhat over 1.0, depending on the type of population studied). Similarly high values were suggested for particulate allergens. Central estimates of this kind of variability, and the close correspondence of the data to lognormal distributions, indicate that 99.9th percentile individuals are likely to respond at doses that are 150 to 450-fold less than would be needed in median individuals. It seems plausible that acute responses with this amount of variability could form part of the mechanistic basis for epidemiological observations of enhanced mortality in relation to ambient exposures to fine particles.     

Toddlers' Reactions to the Distress of Familiar Peers: The Importance of Context

Reactions to peers' distress were recorded for 52 toddlers (hosts), 18 to 36 months old, who were observed playing with familiar peers in their own homes during 2 sessions, 6 months apart. Four contextual factors were explored: the host's responsibility for the guest's distress, similarity between the toddler and the distressed peer, relative familiarity of the peer, and the toddler's experience with peers and siblings. Hosts responded more positively to distress they had caused than to distress they witnessed. Negative reactions were most likely to be shown when hosts themselves had caused the distress of a guest of the same sex. Hosts were less likely to respond either positively or negatively if they had known their guests all their lives. Toddlers who had older siblings were more likely than other hosts to respond negatively to guests' distress.     

Tables for computing shortest confidence intervals involving the f-distribution

Tables of multipliers necessary for computing the shortest confidence interval in situations involving the F-distribution are presented. Such situations are illustrated with several examples.     

Darfurian Livelihoods and Libya: Trade,Migration, and Remittance Flows in Times of Conflict and Crisis1

Labor migration and commerce between Sudan and Libya have long been features of livelihoods in Darfur. This paper describes the importance of historical trade and migration links between Darfur and Libya, and provides a background to the political and economic situation in Libya which has influenced opportunities for Sudanese migrant workers. A case study of the situation of the Darfurian migrants in Kufra (an oasis and transnational trade hub in southern Libya) illustrates how the recent Darfur conflict has affected migration patterns from Darfur and remittance flows in the opposite direction. Official estimates of Darfurian migrant workers in Libya were unavailable but were estimated to be between 150,000 and 250,000. The closure of the national border between Sudan and Libya in May 2003, largely a result of insecurity in Darfur, stopped the traffic of migrant workers between northern Darfur and southern Libya (which prevented the onward travel to Sudan of several thousand migrants in Kufra), and curtailed the well‐established trade routes, communications, and remittance flows. The current limited economic prospects for migrant workers in Libya, combined with the threat of detention, difficulties of return to Sudan, and loss of contact with and uncertainty about the fate of their families in Darfur, have created a sense of despair among many Darfurians. The paper concludes with a series of recommendations to improve the conditions of the Darfurian migrants in Libya, including an amnesty for illegal migrants, and also to ease the travel of migrants, promote communications between Libya and Darfur, and support the flow of remittances.     

U.S. Labor supply and demand in the long run

In this paper we model U.S. labor supply and demand over the next 25 years. Despite the anticipated aging of the population, moderate population growth will provide growing supplies of labor well into the 21st century. Improvements in labor quality due to greater education and experience will also continue for some time, but will eventually disappear. Productivity growth for the U.S. economy will be below long-term historical averages, but labor-using technical change will be a stimulus to the growth of labor demand. Year-to-year changes in economic activity will be primarily the consequence of capital accumulation. However, the driving forces of economic growth over the long term will be demography and technology.