Tracing the historical growth of gerontology

The question of whether gerontology is an emerging new discipline or a variation of older ones is being debated

Atmospheric circulation of hot Jupiters: Coupled radiative-dynamical general circulation model simulations of HD 189733b and HD 209458b

We present global, three-dimensional numerical simulations of HD 189733b and HD 209458b that couple the atmospheric dynamics to a realistic representation of non-gray cloud-free radiative transfer. The model, which we call the Substellar and Planetary Atmospheric Radiation and Circulation (SPARC) model, adopts the MITgcm for the dynamics and uses the radiative model of McKay, Marley, Fortney, and collaborators for the radiation. Like earlier work with simplified forcing, our simulations develop a broad eastward equatorial jet, mean westward flow at higher latitudes, and substantial flow over the poles at low pressure. For HD 189733b, our simulations without TiO and VO opacity can explain the broad features of the observed 8 and 24-micron light curves, including the modest day-night flux variation and the fact that the planet/star flux ratio peaks before the secondary eclipse. Our simulations also provide reasonable matches to the Spitzer secondary-eclipse depths at 4.5, 5.8, 8, 16, and 24 microns and the groundbased upper limit at 2.2 microns. However, we substantially underpredict the 3.6-micron secondary-eclipse depth, suggesting that our simulations are too cold in the 0.1-1 bar region. Predicted temporal variability in secondary-eclipse depths is ~1% at Spitzer bandpasses, consistent with recent observational upper limits at 8 microns. We also show that nonsynchronous rotation can significantly alter the jet structure. For HD 209458b, we include TiO and VO opacity; these simulations develop a hot (>2000 K) dayside stratosphere. Despite this stratosphere, we do not reproduce current Spitzer photometry of this planet. Light curves in Spitzer bandpasses show modest phase variation and satisfy the observational upper limit on day-night phase variation at 8 microns. (abridged)Comment: 20 pages (emulate-apj format), 21 figures, final version now published in ApJ. Includes expanded discussion of radiative-transfer methods and two new figure

Transmission Spectra of Transiting Planet Atmospheres: Model Validation and Simulations of the Hot Neptune GJ 436b for JWST

We explore the transmission spectrum of the Neptune-class exoplanet GJ 436b, including the possibility that its atmospheric opacity is dominated by a variety of non- equilibrium chemical products. We also validate our transmission code by demonstrating close agreement with analytic models that use only Rayleigh scattering or water vapor opacity. We find broad disagreement with radius variations predicted by another published model. For GJ 436b, the relative coolness of the planet's atmosphere, along with its implied high metallicity, may make it dissimilar in character compared to "hot Jupiters." Some recent observational and modeling efforts suggest low relative abundances of H2O and CH4 present in GJ 436b's atmosphere, compared to calculations from equilibrium chemistry. We include these characteristics in our models and examine the effects of absorption from methane-derived higher order hydrocarbons. Significant absorption from HCN and C2H2 are found throughout the infrared, while C2H4 and C2H6 are less easily seen. We perform detailed simulations of JWST observations, including all likely noise sources, and find that we will be able to constrain chemical abundance regimes from this planet's transmission spectrum. For instance, the width of the features at 1.5, 3.3, and 7 microns indicates the amount of HCN versus C2H2 present. The NIRSpec prism mode will be useful due to its large spectral range and the relatively large number of photo-electrons recorded per spectral resolution element. However, extremely bright host stars like GJ 436 may be better observed with a higher spectroscopic resolution mode in order to avoid detector saturation. We find that observations with the MIRI low resolution spectrograph should also have high signal-to-noise in the 5 - 10 micron range due to the brightness of the star and the relatively low spectral resolution (R ~ 100) of this mode.Comment: 33 pages, 12 figures, Accepted to Ap

Physiological Correlates of Volunteering

We review research on physiological correlates of volunteering, a neglected but promising research field. Some of these correlates seem to be causal factors influencing volunteering. Volunteers tend to have better physical health, both self-reported and expert-assessed, better mental health, and perform better on cognitive tasks. Research thus far has rarely examined neurological, neurochemical, hormonal, and genetic correlates of volunteering to any significant extent, especially controlling for other factors as potential confounds. Evolutionary theory and behavioral genetic research suggest the importance of such physiological factors in humans. Basically, many aspects of social relationships and social activities have effects on health (e.g., Newman and Roberts 2013; Uchino 2004), as the widely used biopsychosocial (BPS) model suggests (Institute of Medicine 2001). Studies of formal volunteering (FV), charitable giving, and altruistic behavior suggest that physiological characteristics are related to volunteering, including specific genes (such as oxytocin receptor [OXTR] genes, Arginine vasopressin receptor [AVPR] genes, dopamine D4 receptor [DRD4] genes, and 5-HTTLPR). We recommend that future research on physiological factors be extended to non-Western populations, focusing specifically on volunteering, and differentiating between different forms and types of volunteering and civic participation

High rate of persistent symptoms up to 4 months after community and hospital-managed SARS-CoV-2 infection

Recovery after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains uncertain. A considerable proportion of patients experience persistent symptoms after SARS-CoV-2 infection which impacts health-related quality of life and physical function