381 research outputs found
From Humanitarian Relief to Holocaust Rescue: Tracy Strong Jr., Vichy Internment Camps, and the Maison des Roches in Le Chambon
American relief worker Tracy Strong Jr. played a key role in obtaining the transfer of young prisoners from Vichy internment camps in southern France to the Maison des Roches—a residence that he helped establish in Le Chambon-sur-Lignon—and in subsequently helping some of these young men to escape over the Swiss border. The author of this article bases his research primarily on journals and letters that Strong wrote at the time, which provide contemporary evidence for the central importance of the town's Huguenot congregation and its pastor, André Trocmé—an importance that some writers recently have attributed to postwar exaggeration and myth-making
Is Collective Efficacy Age Graded? The Development and Evaluation of a New Measure of Collective Efficacy for Older Adults
Objectives. Community processes are key determinants of older adults' ability to age in place, but existing scales measuring these constructs may not provide accurate, unbiased measurements among older adults because they were designed with the concerns of child-rearing respondents in mind. This study examines the properties of a new theory-based measure of collective efficacy (CE) that accounts for the perspectives of older residents. Methods. Data come from the population-based Chicago Neighborhood Organization, Aging and Health study (N = 1,151), which surveyed adults aged 65 to 95. Using descriptive statistics, correlations, and factor analysis, we explored the acceptability, reliability, and validity of the new measure. Results. Principal component analysis indicated that the new scale measures a single latent factor. It had good internal consistency reliability, was highly correlated with the original scale, and was similarly associated with neighborhood exchange and disorder, self-rated health, mobility, and loneliness. The new scale also showed less age-differentiated nonresponse compared to the original scale. Discussion. The older adult CE scale has reliability and validity equivalent to that of the existing measure but benefits from a more developed theoretical grounding and reduced likelihood of age-related differential nonresponse
The Atomic-to-Molecular Transition in Galaxies. III. A New Method for Determining the Molecular Content of Primordial and Dusty Clouds
Understanding the molecular content of galaxies is a critical problem in star
formation and galactic evolution. Here we present a new method, based on a
Stromgren-type analysis, to calculate the amount of HI that surrounds a
molecular cloud irradiated by an isotropic radiation field. We consider both
planar and spherical clouds, and H_2 formation either in the gas phase or
catalyzed by dust grains. Under the assumption that the transition from atomic
to molecular gas is sharp, our method gives the solution without any reference
to the photodissociation cross section. We test our results for the planar case
against those of a PDR code, and find typical accuracies of about 10%. Our
results are also consistent with the scaling relations found in Paper I of this
series, but they apply to a wider range of physical conditions. We present
simple, accurate analytic fits to our results that are suitable for comparison
to observations and to implementation in numerical and semi-analytic models.Comment: 14 pages, 5 figures, accepted to Ap
A Climatology of Northwest Missouri Snowfall Events: Long Term Trends and Interannual Variability.
The goal of this study was to develop a 50-year statistical climatology of snowfall
occurrences using data from a dense network of cooperative station observations covering
northwest and central Missouri, and these records were provided by the Missouri Climate Center. This included a study of the long term trends and interannual variability in snowfall occurrence as related to sea surface temperature variations in the Pacific Ocean basin associated with the El
Nino and Southern Oscillation (ENSO) and the North Pacific Oscillation (NPO). These trends and variations were then related to four synoptic-scale flow regimes that produce these snowfalls in the Midwest. The results demonstrate that during the snowfall season (Oct - April) the northwest Missouri region can expect about eight snowfall events which produce three or more inches of accumulation. While no significant long-term trend in overall snowfall occurrence was
found, a decrease in the number of extreme events (10 or more inches) was noted. Also, fewer snowfall events were found during El Nino years, while more heavy snowfall events occurred during "neutral" years, and these results could be related to synoptic- scale variability. A closer examination of the results demonstrated that El Nino/La Nina related variability in snowfall
occurrence was superimposed on longer-term NPO-related variability.This research was supported by the University Corporation for Atmospheric Research (UCAR) Cooperative program for Operational Meteorological Education and Training (COMET) Outreach Programunder award # 98115921
Racial, Ethnic, and Socioeconomic Disparities in Multiple Measures of Blue and Green Spaces in the United States
BACKGROUND: Several studies have evaluated whether the distribution of natural environments differs between marginalized and privileged neighborhoods. However, most studies restricted their analyses to a single or handful of cities and used different natural environment measures. OBJECTIVES: We evaluated whether natural environments are inequitably distributed based on socioeconomic status (SES) and race/ethnicity in the contiguous United States. METHODS: We obtained SES and race/ethnicity data (2015–2019) for all U.S. Census tracts. For each tract, we calculated the Normalized Different Vegetation Index (NDVI) for 2020, NatureScore (a proprietary measure of the quantity and quality of natural elements) for 2019, park cover for 2020, and blue space for 1984–2018. We used generalized additive models with adjustment for potential confounders and spatial autocorrelation to evaluate associations of SES and race/ethnicity with NDVI, NatureScore, park cover, and odds of containing blue space in all tracts ([Formula: see text]) and in urban tracts ([Formula: see text]). To compare effect estimates, we standardized NDVI, NatureScore, and park cover so that beta coefficients presented a percentage increase or decrease of the standard deviation (SD). RESULTS: Tracts with higher SES had higher NDVI, NatureScore, park cover, and odds of containing blue space. For example, urban tracts in the highest median household income quintile had higher NDVI [44.8% of the SD (95% CI: 42.8, 46.8)] and park cover [16.2% of the SD (95% CI: 13.5, 19.0)] compared with urban tracts in the lowest median household income quintile. Across all tracts, a lower percentage of non-Hispanic White individuals and a higher percentage of Hispanic individuals were associated with lower NDVI and NatureScore. In urban tracts, we observed weak positive associations between percentage non-Hispanic Black and NDVI, NatureScore, and park cover; we did not find any clear associations for percentage Hispanics. DISCUSSION: Multiple facets of the natural environment are inequitably distributed in the contiguous United States. https://doi.org/10.1289/EHP1116
The Atomic to Molecular Transition in Galaxies. II: HI and H_2 Column Densities
Gas in galactic disks is collected by gravitational instabilities into giant
atomic-molecular complexes, but only the inner, molecular parts of these
structures are able to collapse to form stars. Determining what controls the
ratio of atomic to molecular hydrogen in complexes is therefore a significant
problem in star formation and galactic evolution. In this paper we use the
model of H_2 formation, dissociation, and shielding developed in the previous
paper in this series to make theoretical predictions for atomic to molecular
ratios as a function of galactic properties. We find that the molecular
fraction in a galaxy is determined primarily by its column density and
secondarily by its metallicity, and is to good approximation independent of the
strength of the interstellar radiation field. We show that the column of atomic
hydrogen required to shield a molecular region against dissociation is ~10 Msun
pc^-2 at solar metallicity. We compare our model to data from recent surveys of
the Milky Way and of nearby galaxies, and show that the both the primary
dependence of molecular fraction on column density and the secondary dependence
on metallicity that we predict are in good agreement with observed galaxy
properties.Comment: Accepted to ApJ. 22 pages, 13 figures, emulateapj format. This
version corrects a minor error in the binning procedure in section 4.1.2. The
remainder of the paper is unchange
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