The Absolute Age of M92

The \textit{absolute age} of a simple stellar population is of fundamental interest for a wide range of applications but is difficult to measure in practice, as it requires an understanding of the uncertainties in a variety of stellar evolution processes as well as the uncertainty in the distance, reddening and composition. As a result, most studies focus only on the \textit{relative age} by assuming that stellar evolution calculations are accurate and using age determinations techniques that are relatively independent of distance and reddening. Here, we construct $20,000$ sets of theoretical isochrones through Monte Carlo simulation using the Dartmouth Stellar Evolution Program to measure the absolute age of the globular cluster M92. For each model, we vary a range of input physics used in the stellar evolution models, including opacities, nuclear reaction rates, diffusion coefficients, atmospheric boundary conditions, helium abundance, and treatment of convection. We also explore variations in the distance and reddening as well as its overall metallicity and $\alpha$ enhancement. We generate simulated Hess diagrams around the main-sequence turn-off region from each set of isochrones and use a Voronoi binning method to fit the diagrams to HST ACS data. We find the age of M92 to be $13.80 \pm 0.75$ Gyr. The $5.4\%$ error in the absolute age is dominated by the uncertainty in the distance to M92 ($\sim 80\%$ of the error budget); of the remaining parameters, only the total metallicity, $\alpha$ element abundance, and treatment of helium diffusion contribute significantly to the total error.Comment: 15 Pages, 14 Figures, 2 Tables; Accepted for Publication A

Longitudinal assessment of cognitive and psychosocial functioning after Hurricanes Katrina and Rita: Exploring disaster impact on middle-aged, older, and oldest-old adults

The authors examined the effects of Hurricanes Katrina and Rita on cognitive and psychosocial functioning in a lifespan sample of adults 6-14 months after the storms. Participants were recruited from the Louisiana Healthy Aging Study. Most were assessed during the immediate impact period and retested for this study. Analyses of pre- and post-disaster cognitive data confirmed that storm-related decrements in working memory for middle-aged and older adults observed in the immediate impact period had returned to pre-hurricane levels in the post-disaster recovery period. Middle-aged adults reported more storm-related stressors and greater levels of stress than the two older groups at both waves of testing. These results are consistent with a burden perspective on post-disaster psychological reactions. © 2012 Wiley Periodicals, Inc

A comparison of adjusted spaced retrieval versus a uniform expanded retrieval schedule for learning a name-face association in older adults with probable Alzheimer\u27s disease

We compared the efficacy of two memory training schedules, adjusted spaced retrieval and uniform expanded retrieval, for learning a name-face association in 12 older adults with probable Alzheimer\u27s disease (AD). Nine training sessions were administered on alternate days for three weeks. Results yielded a positive effect of adjusted spaced retrieval on the proportion of correct recall trials and greater success in transferring the learned information to the live target, compared to the uniform expanded retrieval schedule. These data suggest that the spacing effect may underlie the memorial benefit of spaced retrieval. Implications for practical uses of spaced retrieval are considered

Booster sessions enhance the long-term effectiveness of spaced retrieval in older adults with probable Alzheimer\u27s disease

Six older adults with probable Alzheimer\u27s disease (AD) were trained to recall a name-face association using the spaced retrieval technique. In this study, we retested these persons in a 6-month follow-up program. For half of the participants, three booster sessions were administered at 6, 12, and 18 weeks after original training to promote long-term retention of the name- face association. Results yielded a mnemonic benefit of the booster sessions at retest. Participants were successful in transferring this association to the actual person in the target photograph. These data confirmed the positive effect of spaced retrieval on recall of a name-face association over a 6-month interval. Implications for memory remediation in cognitively impaired older adults are considered

The Absolute Age of M92

The absolute age of a simple stellar population is of fundamental interest for a wide range of applications but is difficult to measure in practice, as it requires an understanding of the uncertainties in a variety of stellar evolution processes as well as the uncertainty in the distance, reddening, and composition. As a result, most studies focus only on the relative age by assuming that stellar evolution calculations are accurate and using age determinations techniques that are relatively independent of distance and reddening. Here, we construct 20,000 sets of theoretical isochrones through Monte Carlo simulation using the Dartmouth Stellar Evolution Program to measure the absolute age of the globular cluster M92. For each model, we vary a range of input physics used in the stellar evolution models, including opacities, nuclear reaction rates, diffusion coefficients, atmospheric boundary conditions, helium abundance, and treatment of convection. We also explore variations in the distance and reddening as well as its overall metallicity and α enhancement. We generate simulated Hess diagrams around the main-sequence turn-off region from each set of isochrones and use a Voronoi binning method to fit the diagrams to Hubble Space Telescope Advanced Camera for Surveys data. We find the age of M92 to be 13.80 ± 0.75 Gyr. The 5.4% error in the absolute age is dominated by the uncertainty in the distance to M92 (∼80% of the error budget); of the remaining parameters, only the total metallicity, α element abundance, and treatment of helium diffusion contribute significantly to the total error

Memory Self-Efficacy and Beliefs about Memory and Aging in Oldest-Old Adults in the Louisiana Healthy Aging Study (LHAS)

UNLABELLED: Background/Study Context. Adaptation to normative age-related declines in memory is an important but understudied aspect of successful aging. The purpose of the present study was to shed new light on memory self-efficacy and beliefs about memory and aging as two integral aspects of adult cognition with relevance to successful aging. METHODS: Young (19 to 27 years) and community-dwelling older adults (60 to 94 years) from the Louisiana Healthy Aging Study (LHAS) completed an adapted Memory Functioning Questionnaire (MFQ) which includes a memory self-efficacy subscale, the Memory Controllability Inventory (MCI), and the Aging Concerns Scale (ACS). RESULTS: Nonagenarians\u27 self-reported memory and beliefs about memory and aging were of central interest. We compared their responses to three younger reference groups to examine hypothesized differences in self-reported memory and beliefs about memory and aging in very late life. Results yielded age effects for most of the MFQ and MCI subscales demonstrating more positive subjective views about memory functioning and control over memory for the young adults. Correlation and regression analyses were conducted to isolate factors that may be associated with memory self-efficacy. Age, symptoms of depression, and memory control beliefs accounted for approximately half of the variance in memory self-efficacy ratings. CONCLUSION: These data indicate that although memory self-efficacy may be age sensitive, we detected no differences in subjective views across the three older groups. Implications for cognitive adaptability and successful aging are considered