Psychosocial Mechanisms Underlying Older Black Men’s Health

Objectives: To evaluate the psychosocial mechanisms underlying older Black men's self-rated health, we examined: (a) the individual, cumulative, and collective effects of stressors on health; (b) the direct effects of psychosocial resources on health; and (c) the stress-moderating effects of psychosocial resources. Method: This study is based on a nationally representative sample of Black men aged 51-81 (N = 593) in the Health and Retirement Study (HRS). Ordinary least squares (OLS) regression models of the psychosocial determinants of self-rated health draw on data from the HRS 2010 and 2012 Core datasets and Psychosocial Modules. Results: Each of the six measures of stressors as well as a cumulative measure of stressors are predictive of worse self-rated health. However, when considered collectively, only two stressors (chronic strains and traumatic events) have statistically significant effects. Furthermore, two of the five psychosocial resources examined (mastery and optimism) have statistically significant protective effects, and prayer moderates the harmful effects of traumatic events on self-rated health. Discussion: Conventional measures of stressors and coping resources-originally developed to account for variance in health outcomes among predominantly white samples-may not capture psychosocial factors most salient for older Black men's health. Future research should incorporate psychosocial measures that reflect their unique experiences

Divergent Pathways: Racial/Ethnic Inequalities in Wealth and Health Trajectories

Extensive empirical evidence documents racial/ethnic disparities in both wealth and health: compared to Whites, Hispanics and Blacks have considerably less wealth and worse health. However, it remains unclear why racial/ethnic inequalities in wealth and health emerge, and whether these inequalities decrease, remain stable, or increase with age. This dissertation aims to fill these gaps in the literature by drawing on life course perspectives and methods to investigate racial/ethnic differences in wealth and health trajectories (i.e., long-term patterns of intra-individual change and stability in wealth and health with age) and how social disadvantage contributes to racial/ethnic wealth and health disparities. The first empirical chapter utilizes panel data from the National Longitudinal Study of Youth (NLSY), a nationally representative survey, and growth curve models to examine racial/ethnic differences in wealth trajectories between ages 21 and 45. Findings reveal that relatively small wealth gaps between Whites, Blacks and Hispanics exist in their early 20s, but these initial inequalities are magnified with age. In the second substantive chapter, data from the Health and Retirement Study (HRS), a nationally representative, longitudinal dataset is used to examine whether racial/ethnic wealth gaps narrow, remain stable, or widen between during the years leading up to retirement (ages 51 and 73). Results show that Whites experience more rapid rates of wealth accumulation than their minority counterparts during middle and later life, resulting in accelerating wealth disparities with age, consistent with a process of cumulative disadvantage. At age 73, the average White household has a net worth of approximately $122,000, whereas both Hispanic and Black household have less than$5,000. Substantial racial/ethnic disparities in wealth trajectories persist after controlling for group differences in life course capital suggesting that other factors such as racial/ethnic differences in portfolio composition, financial transfers, and exposure to discrimination may contribute to wealth disparities. The third substantive chapter uses HRS data to examine racial/ethnic differences in health trajectories. Results indicate that there are dramatic racial/ethnic disparities in both the levels and rates of change in health. Overall, findings from this study show that racial/ethnic inequalities result in divergent aging experiences for Black, Hispanic, and White Americans

The Color of COVID-19: Structural Racism and the Pandemic’s Disproportionate Impact on Older Racial and Ethnic Minorities

Objectives: The aim of this evidence-based theoretically informed essay is to provide an overview of how and why the COVID-19 outbreak is particularly detrimental for the health of older Black and Latinx adults. Methods: We draw upon current events, academic literature, and numerous data sources to illustrate how biopsychosocial factors place older adults at higher risk for COVID-19 relative to younger adults, and how structural racism magnifies these risks for older Black and Latinx adults. Results: We identify three proximate mechanisms through which structural racism operates as a fundamental cause of racial/ethnic inequalities in COVID-19 burden among older adults: (1) Risk of exposure; (2) Weathering processes; and (3) Health care access and quality. Discussion: While the ongoing COVID-19 pandemic is an unprecedented crisis, the racial/ethnic health inequalities among older adults it has exposed are long-standing and deeply rooted in structural racism within American society. This knowledge presents both challenges and opportunities for researchers and policymakers as they seek to address the needs of older adults. It is imperative that federal, state, and local governments collect and release comprehensive data on the number of confirmed COVID-19 cases and deaths by race/ethnicity and age to better gauge the impact of outbreak across minority communities. We conclude with a discussion of incremental steps to be taken to lessen the disproportionate burden of COVID-19 among older Black and Latinx adults, as well as the need for transformative actions that address structural racism in order to achieve population health equity

Pencil-Beam Surveys for Trans-Neptunian Objects: Limits on Distant Populations

Two populations of minor bodies in the outer Solar System remain particularly elusive: Scattered Disk objects and Sedna-like objects. These populations are important dynamical tracers, and understanding the details of their spatial- and size-distributions will enhance our understanding of the formation and on-going evolution of the Solar System. By using newly-derived limits on the maximum heliocentric distances that recent pencil-beam surveys for Trans-Neptunian Objects were sensitive to, we determine new upper limits on the total numbers of distant SDOs and Sedna-like objects. While generally consistent with populations estimated from wide-area surveys, we show that for magnitude-distribution slopes of {\alpha} > 0.7-1.0, these pencil-beam surveys provide stronger upper limits than current estimates in literature.Comment: Submitted to Icaru

Using Multiple-hierarchy Stratification and Life Course Approaches to Understand Health Inequalities: The Intersecting Consequences of Race, Gender, SES, and Age

This study examines how the intersecting consequences of race-ethnicity, gender, socioeconomics status (SES), and age influence health inequality. We draw on multiple-hierarchy stratification and life course perspectives to address two main research questions. First, does racial-ethnic stratification of health vary by gender and/or SES? More specifically, are the joint health consequences of racial-ethnic, gender, and socioeconomic stratification additive or multiplicative? Second, does this combined inequality in health decrease, remain stable, or increase between middle and late life? We use panel data from the Health and Retirement Study (N = 12,976) to investigate between- and within-group differences in in self-rated health among whites, blacks, and Mexican Americans. Findings indicate that the effects of racial-ethnic, gender, and SES stratification are interactive, resulting in the greatest racial-ethnic inequalities in health among women and those with higher levels of SES. Furthermore, racial-ethnic/gender/SES inequalities in health tend to decline with age. These results are broadly consistent with intersectionality and aging-as-leveler hypotheses

Pathways to the all-volunteer military*

The present study investigates the role of a disadvantaged background, the lack of social connectedness, and behavioral problems in channeling young men to the opportunities of the all-volunteer military instead of to college and the labor market

Weak lensing, dark matter and dark energy

Weak gravitational lensing is rapidly becoming one of the principal probes of dark matter and dark energy in the universe. In this brief review we outline how weak lensing helps determine the structure of dark matter halos, measure the expansion rate of the universe, and distinguish between modified gravity and dark energy explanations for the acceleration of the universe. We also discuss requirements on the control of systematic errors so that the systematics do not appreciably degrade the power of weak lensing as a cosmological probe.Comment: Invited review article for the GRG special issue on gravitational lensing (P. Jetzer, Y. Mellier and V. Perlick Eds.). V3: subsection on three-point function and some references added. Matches the published versio

Active Brownian Particles. From Individual to Collective Stochastic Dynamics

We review theoretical models of individual motility as well as collective dynamics and pattern formation of active particles. We focus on simple models of active dynamics with a particular emphasis on nonlinear and stochastic dynamics of such self-propelled entities in the framework of statistical mechanics. Examples of such active units in complex physico-chemical and biological systems are chemically powered nano-rods, localized patterns in reaction-diffusion system, motile cells or macroscopic animals. Based on the description of individual motion of point-like active particles by stochastic differential equations, we discuss different velocity-dependent friction functions, the impact of various types of fluctuations and calculate characteristic observables such as stationary velocity distributions or diffusion coefficients. Finally, we consider not only the free and confined individual active dynamics but also different types of interaction between active particles. The resulting collective dynamical behavior of large assemblies and aggregates of active units is discussed and an overview over some recent results on spatiotemporal pattern formation in such systems is given.Comment: 161 pages, Review, Eur Phys J Special-Topics, accepte

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

Generation and Validation of a Shewanella oneidensis MR-1 Clone Set for Protein Expression and Phage Display

A comprehensive gene collection for S. oneidensis was constructed using the lambda recombinase (Gateway) cloning system. A total of 3584 individual ORFs (85%) have been successfully cloned into the entry plasmids. To validate the use of the clone set, three sets of ORFs were examined within three different destination vectors constructed in this study. Success rates for heterologous protein expression of S. oneidensis His- or His/GST- tagged proteins in E. coli were approximately 70%. The ArcA and NarP transcription factor proteins were tested in an in vitro binding assay to demonstrate that functional proteins can be successfully produced using the clone set. Further functional validation of the clone set was obtained from phage display experiments in which a phage encoding thioredoxin was successfully isolated from a pool of 80 different clones after three rounds of biopanning using immobilized anti-thioredoxin antibody as a target. This clone set complements existing genomic (e.g., whole-genome microarray) and other proteomic tools (e.g., mass spectrometry-based proteomic analysis), and facilitates a wide variety of integrated studies, including protein expression, purification, and functional analyses of proteins both in vivo and in vitro