The Effects of Subjective Survival on Retirement and Social Security Claiming

This research examines the relationship between mortality risk and retirement, and mortality risk and the propensity to take early and reduced Social Security benefits. The main theory for understanding saving behavior is the life-cycle model (LCH). The LCH, however, can be extended to find the optimal retirement age, and can be used to make predictions about the desire to annuitize or equivalently, the desire to delay claiming Social Security benefits. According to the LCH, individuals who expect to be exceptionally long-lived will retire at a later age than individuals who expect to die early because they will need greater wealth to finance more years of retirement. According to almost any model of intertemporal maximization, those who expect to be long lived will see the increase in Social Security benefits that result from retiring at 65 rather than at 62 as being financially advantageous and will, therefore, delay application for benefits until the age of 65. In principle the decision to retire and the decision to take early and reduced benefits are related decisions but not necessarily the same decision. Therefore this study examines both decisions.

The Effects of Subjective Survival on Retirement and Social Security Claiming

According to the life-cycle model, mortality risk will influence both retirement and the desire to annuitize wealth. We estimate the effect of subjective survival probabilities on retirement and on the claiming of Social Security benefits because delayed claiming is equivalent to the purchase of additional Social Security annuities. We find that those with very low subjective probabilities of survival retire earlier and claim earlier than those with higher subjective probabilities, but the effects are not large. The great majority of workers claim as soon as they are eligible.

Social Gerontology- Integrative and Territorial Aspects: A Citation Analysis of Subject Scatter and Database Coverage

To determine the mix of resources used in social gerontology research, a citation analysis was conducted. A representative sample of citations was selected from three prominent gerontology journals and information was added to determine subject scatter and database coverage for the cited materials. Results indicate that a significant portion of gerontology research, even from a social science perspective, relies roughly equally on medical resources as it does social science resources. Furthermore, there is a small but defined core of literature constituting scholarly “territory” unique to gerontology. Analysis of database indexing indicated that broad, interdisciplinary databases provide more comprehensive coverage of the cited materials than do subject-specific databases

Within-host competition does not select for virulence in malaria parasites; studies with Plasmodium yoelii

In endemic areas with high transmission intensities, malaria infections are very often composed of multiple genetically distinct strains of malaria parasites. It has been hypothesised that this leads to intra-host competition, in which parasite strains compete for resources such as space and nutrients. This competition may have repercussions for the host, the parasite, and the vector in terms of disease severity, vector fitness, and parasite transmission potential and fitness. It has also been argued that within-host competition could lead to selection for more virulent parasites. Here we use the rodent malaria parasite Plasmodium yoelii to assess the consequences of mixed strain infections on disease severity and parasite fitness. Three isogenic strains with dramatically different growth rates (and hence virulence) were maintained in mice in single infections or in mixed strain infections with a genetically distinct strain. We compared the virulence (defined as harm to the mammalian host) of mixed strain infections with that of single infections, and assessed whether competition impacted on parasite fitness, assessed by transmission potential. We found that mixed infections were associated with a higher degree of disease severity and a prolonged infection time. In the mixed infections, the strain with the slower growth rate was often responsible for the competitive exclusion of the faster growing strain, presumably through host immune-mediated mechanisms. Importantly, and in contrast to previous work conducted with Plasmodium chabaudi, we found no correlation between parasite virulence and transmission potential to mosquitoes, suggesting that within-host competition would not drive the evolution of parasite virulence in P. yoelii

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Interdisciplinary Research in the Sciences: Implications for Library Organization

published or submitted for publicatio

ARL Academic Science and Technology Libraries: Report of a Survey

published or submitted for publicatio

Saving for Retirement: Wage Growth and Unexpected Events.

Social Security Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/50574/1/wp045.pd