2,761 research outputs found

    Interview with Robert Reynolds, August 23, 2000

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    In the last part of a series of interviews conducted by Michael J. Birkner, Robert Reynolds discussed on August 23, 2000 his life after World War II. After the war, Reynolds moved to Gettysburg. He discussed his time at a rubber factory and his decision to become a teacher at 50. Length of Interview: 49 minutes Collection Note: This oral history was selected from the Oral History Collection maintained by Special Collections & College Archives. Transcripts are available for browsing in the Special Collections Reading Room, 4th floor, Musselman Library. GettDigital contains the complete listing of oral histories done from 1978 to the present. To view this list and to access selected digital versions please visit -- http://gettysburg.cdmhost.com/cdm/landingpage/collection/p16274coll

    Smoking and Mortality Among US Astronauts

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    Astronauts have lower age-specific mortality risk than the U.S. general population from all natural causes of death, particularly cardiovascular disease and cancer. Yet, understanding if they are as healthy as their backgrounds predict they should be, requires that epidemiologists understand (and measure) all potentially confounding exposures in this cohort. Tobacco smoking prevalence has been measured in the U.S. astronaut cohort, but its impact on mortality has not been previously assessed. If smoking history has a negative impact on mortality, this could confound attempts to measure the relative health of astronauts

    Human Health in the Lunar Environment

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    The lunar environment contains many hazards to human health, some common to extraterrestrial locations, some unique to the Moon. Exposures of particular concern are hypobaric environments, hypogravity, space radiation, and lunar dust. This chapter provides a brief overview of these exposures, as they represent the gravest threats to human health in the lunar environment (i.e., they may affect mortality rates) and then reviews the published studies of mortality of the original twenty-four lunar astronauts who visited the Moon between 1969 and 1972. The chapter closes with a reexamination of lunar astronaut mortality using updated data, including detailed discussion of the interpretation of the results

    Using Bayesian Estimation to Quantify the Risks of Spaceflight

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    Complex PRA is the best method and current gold standard, as it allows us to reflect changes (improvements) in individual spacecraft system risks over time. Yet, Bayesian methods using simple inputs allowed us to get estimates that are in line with high-complexity PRA. Here Bayesian estimation acts as a gut check on PRA (supposing a reasonable prior is used). Frequentist calculations can overestimate P(failure), especially when total number of trials are few (e.g., after Challenger). In general, Bayesian probability estimation can be used in any risk assessment situation to integrate what we think we know ahead of time with what we observe over time

    Orbital debris environment for spacecraft designed to operate in low Earth orbit

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    The orbital debris environment model is intended to be used by the spacecraft community for the design and operation of spacecraft in low Earth orbit. This environment, when combined with material-dependent impact tests and spacecraft failure analysis, is intended to be used to evaluate spacecraft vulnerability, reliability, and shielding requirements. The environment represents a compromise between existing data to measure the environment, modeling of this data to predict the future environment, the uncertainty in both measurements and modeling, and the need to describe the environment so that various options concerning spacecraft design and operations can be easily evaluated

    The Effects of Amygdalar Size Normalization on Group Analysis in Late-Life Depression

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    Structural MRI has been utilized in numerous ways to measure morphologic characteristics of subcortical brain regions. Volumetric analysis is frequently used to quantify the size of brain structures to ultimately compare size differences between individuals. In order to make such comparisons, inter-subject variability in brain and/or head size must be taken into consideration. A heterogeneous set of methods are commonly used to normalize regional volume by brain and/or head size yielding inconsistent findings making it diffcult to interpret and compare results from published volumetric studies. This study investigated the effect that various volume normalization methodologies might have on group analysis. Specifically, the amygdalae were the regions of interest in elderly, healthy and depressed individuals. Normalization methods investigated included spatial transformations, brain and head volume, and tissue volume techniques. Group analyses were conducted with independent t-tests by dividing amygdalar volumes by various volume measures, as well as with univariate analysis of covariance (ANCOVA) analyses by using amygdalar volumes as dependent variables and various volume measures as covariates. Repeated measures ANOVA was performed to assess the effect of each normalization procedure. Results indicate that volumetric differences between groups varied based on the normalization method utilized, which may explain, in part, the discrepancy found in amygdalar volumetric studies. We believe the findings of this study are extensible to other brain regions and demographics, and thus, investigators should carefully consider the normalization methods utilized in volumetric studies to properly interpret the results and conclusions

    Mortality of major league baseball players from Canada, Latin America, and the Caribbean

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    Professional baseball players have lower mortality rates than the US general population, but whether this is true of foreign-born players is not known. Using data on ballplayers from six nations, we compare mortality rates with those of US players via standardized mortality ratios. After controlling for confounders, four countries had statistically insignificant SMRs while two nations had significantly elevated SMRs. In the two nations with elevated SMRs, low average ages at death and high crime rates suggest the increased mortality may be linked to violent crime. A full understanding of the causes of disparity in mortality will require further research
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