308 research outputs found

    Space vehicle electrical power systems study

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    Developing suitable solid state power controllers for space vehicles electrical power system

    Cognition in Context: Pathways and Compound Risk in a Sample of US Non-Hispanic Whites

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    The population of individuals with cognitive impairment and dementia is growing rapidly, necessitating etiological investigation. It is clear that individual differences in cognition later in life have both genetic and multi-level environmental correlates. Despite significant recent progress in cellular and molecular research, the exact mechanisms linking genes, brains, and cognition remain elusive. In relation to cognition, it is unlikely that genetic and environmental risk factors function in a vacuum, but rather interact and cluster together. The purpose of the present study was to examine whether aspects of individual socioeconomic status (SES) explain the cognitive genotype-phenotype association, and whether neighborhood SES modifies the effects of genes and individual SES on cognitive ability. Using data from non-Hispanic White participants in the 2016 wave of the Health and Retirement Study, a national sample of United States adults, we examined links between a polygenic score for general cognition and performance-based cognitive functioning. In a series of weighted linear regressions and formal tests of mediation, we observed a significant genotype-phenotype association that was partially attenuated after including individual education to the baseline model, although little reductions were observed for household wealth or census tract-level percent poverty. These findings suggest that genetic risk for poor cognition is partially explained by education, and this pathway is not modified by poverty-level of the neighborhood

    Reproduction in the Western Mud Snake, Farancia abacura reinwardtii (Serpentes: Colubridae), in Arkansas

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    The reproductive cycle of Farancia abacura reinwardtii was studied using samples of snakes collected throughout Arkansas from 1985 to 1991 ;museum specimens were also examined. The right testis of 22 males was examined by light microscopy. Histological analysis of the testis indicated a postnuptial spermatogenic cycle. Testicular recrudescence begins in late May with sperm production peaking in late summer; sperm over winter in the ductus deferens. Ovarian follicles of 22 females were measured and counted; two follicular sizes were noted. In those undergoing primary vitellogenesis, a maximum size of 6.5 mm was reached; those exhibiting secondary vitellogenesis ranged in size from 12 to 21 mm. Average clutch size in females with follicles over 10 mm was 14.6 (n=6). Oviductal eggs were observed in a single female in early September. Female F. abacura require at least 2.5 years to become sexually mature. Follicular growth is slow over the first two years but increases dramatically during the spring of the third year

    Can I Buy My Health? A Genetically Informed Study of Socioeconomic Status and Health

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    Background A large literature demonstrates associations between socioeconomic status (SES) and health, including physiological health and well-being. Moreover, gender differences are often observed among measures of both SES and health. However, relationships between SES and health are sometimes questioned given the lack of true experiments, and the potential biological and SES mechanisms explaining gender differences in health are rarely examined simultaneously. Purpose To use a national sample of twins to investigate lifetime socioeconomic adversity and a measure of physiological dysregulation separately by sex. Methods Using the twin sample in the second wave of the Midlife in the United States survey (MIDUS II), biometric regression analysis was conducted to determine whether the established SES-physiological health association is observed among twins both before and after adjusting for potential familial-level confounds (additive genetic and shared environmental influences that may underly the SES-health link), and whether this association differs among men and women. Results Although individuals with less socioeconomic adversity over the lifespan exhibited less physiological dysregulation among this sample of twins, this association only persisted among male twins after adjusting for familial influences. Conclusions Findings from the present study suggest that, particularly for men, links between socioeconomic adversity and health are not spurious or better explained by additive genetic or early shared environmental influences. Furthermore, gender-specific role demands may create differential associations between SES and health

    Neighborhood Safety Concerns and Daily Well-Being: A National Diary Study

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    People living in unsafe neighborhoods often report poor health. The reasons for this are multi-faceted, but one possibility is that unsafe neighborhoods create a situation of chronic stress, which may deplete people\u27s resources to cope with the daily stressors of life. How people respond to daily stressors (e.g., with increased self-reported negative affect and physical symptoms) is positively associated with health problems and may thus be one pathway linking perceptions of neighborhood safety to poor health. The current study investigated the relationship between neighborhood safety concerns, daily stressors, affective well-being, and physical health symptoms in a national sample of adults from the Midlife in the United States Study II (n = 1748). In 2004, participants reported neighborhood safety concerns and history of chronic stress exposure. Across eight days, they also reported daily stressors, physical symptoms and negative affect. Greater neighborhood safety concerns were associated with higher negative affect and more physical symptoms, adjusting for other sources of chronic stress. Moreover, lower perceived neighborhood safety was related to greater increases in negative affect and physical symptoms on days during which stressors were reported, even after accounting for established interactions between daily stressors and other sources of chronic stress. Exposure to neighborhoods perceived as unsafe is associated with poorer daily well-being and exacerbated responses to daily stressors, which may serve as an individual-level pathway contributing to poorer health among people living in neighborhoods perceived as unsafe

    Application of remote sensing to state and regional problems

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    There are no author-identified significant results in this report

    Neighborhood Socioeconomic Status and Health: A Longitudinal Analysis

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    Higher income neighborhoods are associated with better health, a relation observed in many cross-sectional studies. However, prior research focused on the prevalence of health conditions, and examining the incidence of new health conditions may provide stronger support for a potential causal role of neighborhoods on health. We used the 2004 and 2014 waves of the Midlife in the United States Study (n = 1726; ages 34–83) to examine health condition incidence as a function of neighborhood income. Among participants who had lived in the same neighborhood across the time period, we hypothesized that higher neighborhood income would be associated with a lower incidence of health conditions ten years later. Health included 18 chronic conditions related to mental (anxiety, depression) and physical (cardiovascular, immune) health. Multinomial logistic regression analyses adjusting for individual income and sociodemographics indicated that the odds of developing two or more new health conditions (no new health conditions as referent), was significantly lower (OR = 0.92, CI: 0.86, 0.99) for every $10,000 increment in neighborhood income. Associations did not vary by age or neighborhood tenure. Results add to a literature documenting that higher neighborhood income is associated with better health

    Benefit-cost methodology study with example application of the use of wind generators

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    An example application for cost-benefit methodology is presented for the use of wind generators. The approach adopted for the example application consisted of the following activities: (1) surveying of the available wind data and wind power system information, (2) developing models which quantitatively described wind distributions, wind power systems, and cost-benefit differences between conventional systems and wind power systems, and (3) applying the cost-benefit methodology to compare a conventional electrical energy generation system with systems which included wind power generators. Wind speed distribution data were obtained from sites throughout the contiguous United States and were used to compute plant factor contours shown on an annual and seasonal basis. Plant factor values (ratio of average output power to rated power) are found to be as high as 0.6 (on an annual average basis) in portions of the central U. S. and in sections of the New England coastal area. Two types of wind power systems were selected for the application of the cost-benefit methodology. A cost-benefit model was designed and implemented on a computer to establish a practical tool for studying the relative costs and benefits of wind power systems under a variety of conditions and to efficiently and effectively perform associated sensitivity analyses

    What Predicts How Safe People Feel in Their Neighborhoods and Does It Depend on Functional Status?

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    Feeling unsafe in one\u27s neighborhood is related to poor health. Features of the neighborhood environment have been suggested to inform perceptions of neighborhood safety. Yet, the relative contribution of these features (e.g., uneven sidewalks, crime, perceived neighborhood physical disorder) on perceived neighborhood safety, particularly among people with disabilities who may view themselves as more vulnerable, is not well understood. We examined whether sidewalk quality assessed by third party raters, county-level crime rates, and perceived neighborhood disorder would relate to neighborhood safety concerns, and whether functional limitations would exacerbate these links. Using data from the 2012/2014 waves of the Health and Retirement Study (n = 10,653, mean age = 66 years), a national sample of older US adults, we demonstrate that those with and without functional limitations felt less safe in areas with more crime and perceived as more disordered. When considered simultaneously, however, only perceived disorder statistically significantly predicted safety concerns. Living in neighborhoods with better sidewalk quality was statistically significantly related to feeling less safe, but only among those with functional limitations. Sidewalk quality was not statistically significantly related to safety reports among those without functional limitations. To our knowledge, this study is among the first to examine multiple features of the neighborhood environment simultaneously in relation to perceived neighborhood safety. Our findings highlight the relative importance of perceived physical disorder, and that these perceptions relate to safety concerns. Replication of this research is needed to determine the robustness of these patterns, including rich data on pedestrian use and sidewalk proximity to roadways. Community-level interventions that simultaneously target the multifaceted features of the neighborhood environment that shape people\u27s safety reports may be needed to reduce burden of health
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