International Diversification of Pension Assets Is No Panacea for Population Aging

Six years ago,The Economist wrote that investing retirement savings in developed countries in the emerging markets of still-youthful developing countries promised to "beat demography." As labor force growth slows in the North, runs this argument, capital becomes abundant relative to labor and the rate of return to this capital declines. By investing in the South, not only do OECD investors earn a higher rate of return on their savings, but the rate of return to that capital which remains in the North is boosted as well, because there is less of it. Working with a two-region neoclassical economic-demographic model, the authors show that reallocating capital from North to South can, at most, only slightly attenuate the negative macroeconomic impacts of population aging. Moreover, the reallocaion gives rise to significant, and thus politically challenging, shifts in the distribution of income between working- and retirement-age populations in both regions

Globalization, Social Security, and International Transfers

In this paper, we quantify the impact of globalization (i.e., integration of global capital markets) on intergenerational transfers mediated through Pay As You Go (PAYG) public pension systems in more developed countries (MDCs), as well as impacts on the intergenerational distribution of income and wealth. Our basic finding is that, while globalization is likely to erode the pension income of older persons, it will enhance their wealth, leaving their overall spending power little changed. The working age population, which earns lower wages, is an unambiguous loser from the globalization process, at least to the extent that we limit ourselves to a neoclassical analysis of the phenomenon. The main impact of globalization is unlikely, however, to be captured by economy-wide averages such as those presented in this paper. This is the redistribution from lifetime non-savers, especially the poor, who depend on labor income while young and wage-based intergenerational transfers when old, to lifetime savers, who are able to take advantage of improved capital returns. While we concentrate on MDCs in this paper, we make the point that economic impacts of globalization in less developed countries (LDCs) are opposite in sign and greater in relative magnitude. The latter is the case because reallocation of capital gives rise to a greater proportional change in the capital-output ratio in LDCs than in MDCs

Isolation of Genotype V St. Louis Encephalitis Virus in Florida

We isolated and characterized St. Louis encephalitis virus (SLEV) from cloacal swabs of naturally exposed adult sentinel chickens in 2006. Phylogenetic analysis of SLEV strains isolated in Florida indicated that Brazilian SLEV circulated in 1972 and 2006; lineages were VA and VB

Male mating biology

Before sterile mass-reared mosquitoes are released in an attempt to control local populations, many facets of male mating biology need to be elucidated. Large knowledge gaps exist in how both sexes meet in space and time, the correlation of male size and mating success and in which arenas matings are successful. Previous failures in mosquito sterile insect technique (SIT) projects have been linked to poor knowledge of local mating behaviours or the selection of deleterious phenotypes during colonisation and long-term mass rearing. Careful selection of mating characteristics must be combined with intensive field trials to ensure phenotypic characters are not antagonistic to longevity, dispersal, or mating behaviours in released males. Success has been achieved, even when colonised vectors were less competitive, due in part to extensive field trials to ensure mating compatibility and effective dispersal. The study of male mating biology in other dipterans has improved the success of operational SIT programmes. Contributing factors include inter-sexual selection, pheromone based attraction, the ability to detect alterations in local mating behaviours, and the effects of long-term colonisation on mating competitiveness. Although great strides have been made in other SIT programmes, this knowledge may not be germane to anophelines, and this has led to a recent increase in research in this area

Does reservoir host mortality enhance transmission of West Nile virus?

<p>Abstract</p> <p>Background</p> <p>Since its 1999 emergence in New York City, West Nile virus (WNV) has become the most important and widespread cause of mosquito-transmitted disease in North America. Its sweeping spread from the Atlantic to the Pacific coast was accompanied by widespread mortality among wild birds, especially corvids. Only sporadic avian mortality had previously been associated with this infection in the Old World. Here, we examine the possibility that reservoir host mortality may intensify transmission, both by concentrating vector mosquitoes on remaining hosts and by preventing the accumulation of "herd immunity".</p> <p>Results</p> <p>Inspection of the Ross-Macdonald expression of the basic reproductive number (<it>R</it>₀) suggests that this quantity may increase with reservoir host mortality. Computer simulation confirms this finding and indicates that the level of virulence is positively associated with the numbers of infectious mosquitoes by the end of the epizootic. The presence of reservoir incompetent hosts in even moderate numbers largely eliminated the transmission-enhancing effect of host mortality. Local host die-off may prevent mosquitoes to "waste" infectious blood meals on immune host and may thus facilitate perpetuation and spread of transmission.</p> <p>Conclusion</p> <p>Under certain conditions, host mortality may enhance transmission of WNV and similarly maintained arboviruses and thus facilitate their emergence and spread. The validity of the assumptions upon which this argument is built need to be empirically examined.</p

Sources and transformations of particle-bound polycyclic aromatic hydrocarbons in Mexico City

Understanding sources, concentrations, and transformations of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere is important because of their potent mutagenicity and carcinogenicity. The measurement of particle-bound PAHs by three different methods during the Mexico City Metropolitan Area field campaign in April 2003 presents a unique opportunity for characterization of these compounds and intercomparison of the methods. The three methods are (1) collection and analysis of bulk samples for time-integrated gas- and particle-phase speciation by gas chromatography/mass spectrometry; (2) aerosol photoionization for fast detection of PAHs on particles' surfaces; and (3) aerosol mass spectrometry for fast analysis of size and chemical composition. This research represents the first time aerosol mass spectrometry has been used to measure ambient PAH concentrations and the first time that fast, real-time methods have been used to quantify PAHs alongside traditional filter-based measurements in an extended field campaign. Speciated PAH measurements suggest that motor vehicles and garbage and wood burning are important sources in Mexico City. The diurnal concentration patterns captured by aerosol photoionization and aerosol mass spectrometry are generally consistent. Ambient concentrations of particle-phase PAHs typically peak at ~110 ng m^-3 during the morning rush hour and rapidly decay due to changes in source activity patterns and dilution as the boundary layer rises, although surface-bound PAH concentrations decay faster. The more rapid decrease in surface versus bulk PAH concentrations during the late morning suggests that freshly emitted combustion-related particles are quickly coated by secondary aerosol material in Mexico City's atmosphere and may also be transformed by heterogeneous reactions