The Retirement Decision: Current Influences on the Timing of Retirement among Older Workers

This paper investigates the influences on retirement behavior among older workers who were surveyed by the Health and Retirement Study (1992-2004). It is found that increases in all categories of wealth (pension, housing equity and other financial wealth) raise the probability of retiring, while good earnings prospects induce continued employment. Retirement plan types have significant impacts: workers covered by defined benefit (DB) plans are more likely to retire, while the defined contribution (DC) plan coverage significantly delays retirement. Furthermore, the probability and thus timing of retirement for DC plan participants are susceptible to the influence of business cycles through income flow fluctuations that are due to investment performance and interest rate changes. Health insurance (HI), if conditional on employment, strongly defers retirement, while alternative sources of insurance such as employer-sponsored retiree HI, spouse’s HI, public HI or COBRA coverage, encourages labor force exit. The scheduled increases in the full retirement age for Social Security act to encourage younger cohorts to work longer

Retiring on the House? Cross-Cohort Differences in Housing Wealth

This chapter evaluates the role of housing wealth in Baby Boomers’ retirement prospects, to determine what role housing wealth will play in their retirement wellbeing. Our approach compares the wealth position of the leading edge of the Boomers with that of the generation immediately preceding it, in the years just prior to retirement. We rely on the Health and Retirement Survey (HRS) and compare persons age 51-61 in 1992, whom we refer to as the original HRS cohort, with the Early Baby Boomers interviewed at age 51-56 interviewed in 2004. We find that Boomers do have more valuable homes, but they have also borrowed more against them, so they have a similar fraction of assets allocated to home equity as their predecessors. Unlike prior studies, we find that people do view housing as a source of wealth that can help them finance their retirement needs. Indeed, a substantial fraction of older households do move, and in the process, they appear to liquidate some home equity which they convert to financial assets. Consequently, some of the home equity extraction observed in recent years may be related to the aging of the population, rather than a cyclical response to rapid house appreciation

The Retirement Decision: Current Influences on the Timing of Retirement among Older Workers

This paper investigates the influences on retirement behavior among older workers who were surveyed by the Health and Retirement Study (1992-2004). It is found that increases in all categories of wealth (pension, housing equity and other financial wealth) raise the probability of retiring, while good earnings prospects induce continued employment. Retirement plan types have significant impacts: workers covered by defined benefit (DB) plans are more likely to retire, while the defined contribution (DC) plan coverage significantly delays retirement. Furthermore, the probability and thus timing of retirement for DC plan participants are susceptible to the influence of business cycles through income flow fluctuations that are due to investment performance and interest rate changes. Health insurance (HI), if conditional on employment, strongly defers retirement, while alternative sources of insurance such as employer-sponsored retiree HI, spouse's HI, public HI or COBRA coverage, encourages labor force exit. The scheduled increases in the full retirement age for Social Security act to encourage younger cohorts to work longer.

Both interaction surfaces within cohesin's hinge domain are essential for its stable chromosomal association

BackgroundThe cohesin complex that mediates sister chromatid cohesion contains three core subunits: Smc1, Smc3, and Scc1. Heterotypic interactions between Smc1 and Smc3 dimerization domains create stable V-shaped Smc1/Smc3 heterodimers with a hinge at the center and nucleotide-binding domains (NBDs) at the ends of each arm. Interconnection of each NBD through their association with the N- and C-terminal domains of Scc1 creates a tripartite ring, within which sister DNAs are thought to be entrapped (the ring model). Crystal structures show that the Smc1/Smc3 hinge has a toroidal shape, with independent “north” and “south” interaction surfaces on an axis of pseudosymmetry. The ring model predicts that sister chromatid cohesion would be lost by transient hinge opening.ResultsWe find that mutations within either interface weaken heterodimerization of isolated half hinges in vitro but do not greatly compromise formation of cohesin rings in vivo. They do, however, reduce the residence time of cohesin on chromosomes and cause lethal defects in sister chromatid cohesion. This demonstrates that mere formation of rings is insufficient for cohesin function. Stable cohesion requires cohesin rings that cannot easily open.ConclusionsEither the north or south hinge interaction surface is sufficient for the assembly of V-shaped Smc1/Smc3 heterodimers in vivo. Any tendency of Smc proteins with weakened hinges to dissociate will be suppressed by interconnection of their NBDs by Scc1. We suggest that transient hinge dissociation caused by the mutations described here is incompatible with stable sister chromatid cohesion because it permits chromatin fibers to escape from cohesin rings.HighlightsUnstable Smc1/3 hinge dimerization reduces the residence time of cohesin on chromatin<br/

A positively charged channel within the Smc1/Smc3 hinge required for sister chromatid cohesion

Cohesin's structural maintenance of chromosome 1 (Smc1) and Smc3 are rod-shaped proteins with 50-nm long intra-molecular coiled-coil arms with a heterodimerization domain at one end and an ABC-like nucleotide-binding domain (NBD) at the other. Heterodimerization creates V-shaped molecules with a hinge at their centre. Inter-connection of NBDs by Scc1 creates a tripartite ring within which, it is proposed, sister DNAs are entrapped. To investigate whether cohesin's hinge functions as a possible DNA entry gate, we solved the crystal structure of the hinge from Mus musculus, which like its bacterial counterpart is characterized by a pseudo symmetric heterodimeric torus containing a small channel that is positively charged. Mutations in yeast Smc1 and Smc3 that together neutralize the channel's charge have little effect on dimerization or association with chromosomes, but are nevertheless lethal. Our finding that neutralization reduces acetylation of Smc3, which normally occurs during replication and is essential for cohesion, suggests that the positively charged channel is involved in a major conformational change during S phase.<br/