538 research outputs found

    One-dimensional numerical analysis of the transient thermal response of multilayer insulative systems

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    A one-dimensional numerical analysis of the transient thermal response of multilayer insulative systems has been developed. The analysis can determine the temperature distribution through a system consisting of from one to four layers, one of which can be an air gap. Concentrated heat sinks at any interface can be included. The computer program based on the analysis will determine the thickness of a specified layer that will satisfy a temperature limit criterion at any point in the insulative system. The program will also automatically calculate the thickness at several points on a vehicle and determine total system mass

    Chemical equilibrium of ablation materials including condensed species

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    Equilibrium is determined by finding chemical composition with minimum free energy. Method of steepest descent is applied to quadratic representation of free-energy surface. Solution is initiated by selecting arbitrary set of mole fractions, from which point on free-energy surface is computed

    What Is Urban Environmental Stewardship? Constructing a Practitioner-Derived Framework

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    Agencies and organizations deploy various strategies in response to environmental challenges, including the formulation of policy, programs, and regulations. Citizen-based environmental stewardship is increasingly seen as an innovative and important approach to improving and conserving landscape health. A new research focus on the stewardship of urban natural resources is being launched by the U.S. Forest Service in the Pacific Northwest region. Early scoping efforts are addressing various scales of human systems ranging from individuals to organizations to the entire positive “footprint” of stewardship on the land. This report addresses a fundamental need—to understand and describe civic environmental stewardship in urban settings. Stewardship has been described and defined in diverse ways within a variety of contexts, including the philosophical literature of environmentalism, agency program descriptions, and outreach by sponsoring organizations. Constructing a framework to convey the layered meanings of stewardship will help to focus and guide future research. A cognitive mapping technique was used to elicit responses to the question “What is environmental stewardship?” Semistructured interviews were conducted with representatives of nine Seattle environmental organizations, a group of practitioners who collectively represent over 100 years of experience in the field. Program planners and managers have particularly direct experiences of stewardship. Cognitive mapping enables participants to explore, then display, their particular knowledge and perceptions about an idea or activity. Analysis generated thematic, structural representations of shared concepts. Results show that the practitioners have multilayered perceptions of stewardship, from environmental improvement to community building, and from actions to outcomes. The resulting conceptual framework demonstrates the full extent of stewardship activity and meaning, which can aid stewardship sponsors to improve stewardship programs, leading to better experiences for participants and higher quality outcomes for projects and environments

    A latent class analysis of stigmatizing attitudes and knowledge of HIV risk among youth in South Africa

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    Background: The current study aims to investigate how the ability to accurately gauge risk factors associated with contracting HIV while taking into consideration various individual and community level socio-demographic characteristics (e.g., race and poverty) predicts the nature of stigmatizing attitudes toward persons with HIV. Methods: Data from a sample of 1,347 Cape Town area youth who participated in the Cape Area Panel Study (CAPS) Wave 2a were used. Latent Class Analysis was conducted to ascertain whether response patterns regarding knowledge of HIV contraction suggest the presence of subgroups within the sample. Results: Findings indicate that there are four latent classes representing unique response pattern profiles regarding knowledge of HIV contraction. Additionally, our results suggest that those in South Africa who are classified as "white," live in more affluent communities, and have more phobic perceptions of HIV risk are also more likely to have the most stigmatizing attitudes toward those who are HIV positive. Conclusion: Implications of these findings include extending HIV knowledge, education, and awareness programs to those who are not traditionally targeted in an attempt to increase levels of knowledge about HIV and, consequently, decrease stigma

    Risk of COVID-19 infection among prison staff in the United States

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    Background: Multiple large outbreaks of COVID-19 have been documented in prisons and jails across regions of the world, with hazardous environmental conditions amplify the risks of exposure for both incarcerated people and correctional staff. The objectives of this study are to estimate the cumulative prevalence of COVID-19 cases among U.S. prison staff over time and compare it to the prison inmate population and the general U.S. population, overall, and to examine risk of COVID-19 infection among prison staff across jurisdictions. Methods: We use publicly available data (April 22, 2020 to January 15, 2021) to estimate COVID-19 crude case rates per 1000 with 95% confidence intervals over the study period for prison staff, incarcerated population, and general population. We also compare COVID-19 case rates between prison staff and the general population within jurisdictions. Results: Over the study period, prison staff have reported consistently higher rates of COVID-19 compared to the general population, with prison staff case rates more closely mirroring the incarcerated population case rates. The rolling 7-day average case rates for prison staff, prison population, and general population on January 15, 2021 were 196.04 per 1000 (95%CI 194.81, 197.26), 219.16 (95%CI 218.45, 219.86), and 69.80 (95%CI 69.78, 69.83), respectively. There was substantial heterogeneity across jurisdictions, yet in 87% of study jurisdictions, the risk of COVID-19 was significantly greater among prison staff than the general state population. Conclusions: Targeting staff for COVID-19 mitigation strategies is essential to protect the health of people who intersect with the correctional system and to flatten the curve in the surrounding communities

    COVID-19 cases and testing in 53 prison systems

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    Background: COVID-19 has entered United States prison systems at alarming rates. Disparities in social and structural determinants of health disproportionately affect those experiencing incarceration, making them more vulnerable to COVID-19. Additionally, prisons are sites of congregate living, making it impossible to practice social distancing, and most prisons have relied only on incremental measures to reduce risk and spread of COVID-19. To more fully understand the impact that COVID-19 is having on incarcerated populations, it is critical to have systematic data on testing, test positivity, cases, and case fatality. Using data from the COVID Prison Project, we present data on 53 prison systems COVID-19 testing, test positivity, case, and case fatality by state and compare these data with each state’s general population. We do this for the early stages of the pandemic, utilizing data through July 15, 2020. Results: Many states are not reporting full information on COVID testing with some also not reporting on case fatality. Among those reporting data, there is a wide variation between testing, test positivity, and case rates within prison systems and as compared to the general population. However, when more tests are deployed more cases are identified with the majority of state prisons having higher case rates than their general population. Conclusions: These findings underscore the need for the implementation and study of COVID-19 mitigation and surveillance strategies to flatten the COVID-19 curve in prisons across the country. We call for future research to build on these data from the COVID Prison Project to protect the health of our nations’ often forgotten residents

    An assessment of the readiness of ablative materials for preflight application to the shuttle orbiter

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    The shuttle orbiter relies primarily on a reusable surface insulation (RSI) thermal protection system (TPS). The RSI is very efficient in its thermal performance; however, the RSI tile system has shown poor mechanical integrity. The state-of-the-art of the ablative TPS is reviewed, and an assessment made of the ablator's readiness for use on the shuttle orbiter. Unresolved technical issues with regard to the ablative TPS are identified. Short time, highly focused analytical and experimental programs were initiated to: (1) identify candidate ablation materials; (2) assess the data base for these materials; (3) evaluate the need and kind of waterproof coating; (4) calculate thermal and other stresses in an ablator tile; (5) identify an acceptable ablator/RSI tile joint filler; and (6) assess the sensitivity of the ablator to sequential heat pulses. Results from some of these programs are discussed

    COVID-19 Exposes Need for Progressive Criminal Justice Reform

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    Modeling conducted by the Centers for Disease Control and Prevention calculates that as many as 160 to 214 million people in the United States could become infected by the 2019 novel coronavirus (SARS-CoV-2, which causes the disease COVID-19) and that as many as 200 000 to 1.7 million may die from COVID-19

    A Call to Action to Public Health Institutions and Teaching to Incorporate Mass Incarceration as a Sociostructural Determinant of Health

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    Mass incarceration refers to the system of social and racial control in the United States that arrests, convicts, incarcerates, and supervises racial and ethnic minority populations through probation and parole. Mass incarceration is referred to as “mass” because the current size of this system in the United States is historically and internationally unparalleled. Mass incarceration affects those who are incarcerated and under community supervision, as well as the families and communities where it is concentrated. Mass incarceration is a pervasive cause of health inequities in the United States
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