1,575 research outputs found

    NASA/MSFC Large Stretch Press Study

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    The purpose of this study was to: A. assess and document the advantages/disadvantages of a government agency investment in a large stretch form press on the order of 5000 tons capacity (per jaw); B. develop a procurement specification for the press; and C. provide trade study data that will permit an optimum site location. Tasks were separated into four major elements: cost study, user survey, site selection, and press design/procurement specification

    Ecological Effects of Fear: How Spatiotemporal Heterogeneity in Predation Risk Influences Mule Deer Access to Forage in a Sky‐Island System

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    Forage availability and predation risk interact to affect habitat use of ungulates across many biomes. Within sky‐island habitats of the Mojave Desert, increased availability of diverse forage and cover may provide ungulates with unique opportunities to extend nutrient uptake and/or to mitigate predation risk. We addressed whether habitat use and foraging patterns of female mule deer (Odocoileus hemionus) responded to normalized difference vegetation index (NDVI), NDVI rate of change (green‐up), or the occurrence of cougars (Puma concolor). Female mule deer used available green‐up primarily in spring, although growing vegetation was available during other seasons. Mule deer and cougar shared similar habitat all year, and our models indicated cougars had a consistent, negative effect on mule deer access to growing vegetation, particularly in summer when cougar occurrence became concentrated at higher elevations. A seemingly late parturition date coincided with diminishing NDVI during the lactation period. Sky‐island populations, rarely studied, provide the opportunity to determine how mule deer respond to growing foliage along steep elevation and vegetation gradients when trapped with their predators and seasonally limited by aridity. Our findings indicate that fear of predation may restrict access to the forage resources found in sky islands

    A Variable Coeficient of Restitution Experiment on a Linear Air Track

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    A system consisting of two pendula attached to an air cart is mathematically analyzed, and the coefficient of restitution is shown to pass through a deep minimum. The solution to the small angle equation of motion is transcendental and provides an exercise in graphical methods for the beginning mechanics student

    STRATIGRAPHIC INVESTIGATIONS AT BARBER CREEK (31PT259) : RECONSTRUCTING THE CULTURE-HISTORY OF A MULTICOMPONENT SITE IN THE NORTH CAROLINA COASTAL PLAIN

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    Barber Creek is a multicomponent stratified site situated atop a relict sand dune in eastern North Carolina. Previous research has put emphasis on site formation and occupation. The focus of this study was to reconstruct the cultural chronology of the west-central portion of Barber Creek and compare it to previous analyses from other portions of the site. This study resulted in the identification of three former occupation surfaces, or floors, buried in approximately one meter of aeolian sands. These occupation floors date to the Early Archaic, Middle to Late Archaic and Early to Middle Woodland periods. The stratified remains of three discrete occupation floors identified in this investigation are largely consistent with previous investigations at the site. The artifact backplots reconstructed here are the clearest evidence yet for a stratified sequence at Barber Creek. In fact, the results of this study provide the best evidence thus far for the presence of Early Archaic, Middle to Late Archaic, and Woodland components in stratified contexts in the Coastal Plain of North Carolina. Great potential exists at Barber Creek and other such stratified sites along the Tar River to answer questions concerning chronology and typology related to the prehistory of the North Carolina Coastal Plain.  M.A

    Long-Term SGRQ Stability in a Cohort of Individuals with Alpha-1 Antitrypsin Deficiency-Associated Lung Disease

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    Radmila Choate,1 Kristen E Holm,2,3 Robert A Sandhaus,2,3 David M Mannino,4 Charlie Strange3,5 1University of Kentucky College of Public Health, Lexington, Kentucky, USA; 2Department of Medicine, National Jewish Health, Denver, Colorado, USA; 3Alphanet, Inc., Coral Gables, Florida, USA; 4University of Kentucky College of Medicine, Lexington, Kentucky, USA; 5Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Medical University of South Carolina, Charleston, South Carolina, USACorrespondence: Radmila Choate, University of Kentucky College of Public Health, Lexington, Kentucky, USA, Tel +1 859-218-2237, Email [email protected]: Health-related quality of life (HRQoL) assessments such as St. George’s Respiratory Questionnaire (SGRQ) are often used as outcome measures to evaluate patient-perceived changes in health status among individuals with lung disease. Several factors have been linked to deterioration in SGRQ, including symptoms (dyspnea, wheezing) and exercise intolerance. Whether these findings apply to individuals with alpha-1 antitrypsin deficiency (AATD) remains incompletely studied. This longitudinal study examines the trajectory of SGRQ scores in a cohort of United States individuals with AATD-associated lung disease and defines factors associated with longitudinal change.Methods: Individuals with AATD-associated lung disease enrolled in AlphaNet, a disease management program, who had ≥ 3 SGRQ measurements collected between 2009 and 2019, and baseline data for clinically important variables were included in these analyses. Data collected after lung transplants were excluded. Mixed-effects model analyses were used to evaluate the changes in SGRQ total and subscale scores over time and by modified Medical Research Council (mMRC) Scale, use of oxygen, age, sex, productive cough, and exacerbation frequency at baseline. Sensitivity analyses were conducted to examine the potential effect of survivor bias.Results: Participants (n=2456, mean age 57.1± 9.9 years, 47% female) had a mean SGRQ total score of 44.7± 18.9 at baseline, 48% used oxygen regularly, and 55% had ≥ 2 exacerbations per year. The median length of follow-up was 6 (IQR 3– 9) years. The SGRQ total score and subscales remained stable throughout the observation period. Age, mMRC categories, presence or absence of productive cough, frequency of exacerbations, and use of oxygen at baseline were significantly associated with the rate of change of SGRQ total (p< 0.0001).Conclusion: We observed long-term stability in HRQoL and an association between the rate of change in SGRQ and baseline mMRC, exacerbation frequency, productive cough, and use of oxygen in this cohort of individuals with AATD-associated lung disease.Keywords: COPD, alpha-1 antitrypsin deficiency, quality of lif

    Walking All over COVID-19: The Rapid Development of STRIDE in Your Room, an Innovative Approach to Enhance a Hospital-Based Walking Program during the Pandemic

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    Hospitalization is common among older adults. Prolonged time in bed during hospitalization can lead to deconditioning and functional impairments. Our team is currently working with Department of Veterans Affairs (VA) medical centers across the United States to implement STRIDE (assiSTed eaRly mobIlity for hospitalizeD older vEterans), a hospital-based walking program designed to mitigate the risks of immobility during hospitalization. However, the COVID-19 pandemic made in-person, or face-to-face, walking challenging due to social distancing recommendations and infection control concerns. In response, our team applied principles of implementation science, including stakeholder engagement, prototype development and refinement, and rapid dissemination and feedback, to create STRIDE in Your Room (SiYR). Consisting of self-guided exercises, light exercise equipment (e.g., TheraBands, stress ball, foam blocks, pedometer), the SiYR program provided safe alternative activities when face-to-face walking was not available during the pandemic. We describe the methods used in developing the SiYR program; present feedback from participating sites; and share initial implementation experiences, lessons learned, and future directions

    Mechanical Activation of Al-Oxyhydroxide Minerals – Physicochemical Changes, Reactivity and Relevance to Bayer Process

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    Overview of our research on ‘structure and reactivity’ of gibbsite and boehmite under varied conditions of mechanical activation, e.g. milling energy and presence of a second phase is presented. Bulk and surface changes induced in the solids by milling are characterized in terms of morphology, particle size distribution, specific surface area and nature of porosity, crystallite size and zeta potential. Results on enhanced amorphisation of gibbsite in presence of a second phase (quartz, hematite etc), changes in zeta potential of gibbsite due to loss of texture during milling and anomalous decrease in surface area of boehmite during milling are reported. Reactivity of the activated solids in sodium hydroxide and variation in thermal transformation temperatures is correlated with physicochemical characteristics of the samples and plausible explanation for the observed correlations presented. Significance of the results with specific reference to bauxite and alumina processing in Bayer process is highlighted

    What is the importance of climate model bias when projecting the impacts of climate change on land surface processes?

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    Regional climate change impact (CCI) studies have widely involved downscaling and bias correcting (BC) global climate model (GCM)-projected climate for driving land surface models. However, BC may cause uncertainties in projecting hydrologic and biogeochemical responses to future climate due to the impaired spatiotemporal covariance of climate variables and a breakdown of physical conservation principles. Here we quantify the impact of BC on simulated climate-driven changes in water variables (evapotranspiration (ET), runoff, snow water equivalent (SWE), and water demand for irrigation), crop yield, biogenic volatile organic compounds (BVOC), nitric oxide (NO) emissions, and dissolved inorganic nitrogen (DIN) export over the Pacific Northwest (PNW) region. We also quantify the impacts on net primary production (NPP) over a small watershed in the region (HJ-Andrews). Simulation results from the coupled ECHAM5–MPI-OM model with A1B emission scenario were first dynamically downscaled to 12 km resolution with the WRF model. Then a quantile-mapping-based statistical downscaling model was used to downscale them into 1/16° resolution daily climate data over historical and future periods. Two climate data series were generated, with bias correction (BC) and without bias correction (NBC). Impact models were then applied to estimate hydrologic and biogeochemical responses to both BC and NBC meteorological data sets. These impact models include a macroscale hydrologic model (VIC), a coupled cropping system model (VIC-CropSyst), an ecohydrological model (RHESSys), a biogenic emissions model (MEGAN), and a nutrient export model (Global-NEWS). Results demonstrate that the BC and NBC climate data provide consistent estimates of the climate-driven changes in water fluxes (ET, runoff, and water demand), VOCs (isoprene and monoterpenes) and NO emissions, mean crop yield, and river DIN export over the PNW domain. However, significant differences rise from projected SWE, crop yield from dry lands, and HJ-Andrews's ET between BC and NBC data. Even though BC post-processing has no significant impacts on most of the studied variables when taking PNW as a whole, their effects have large spatial variations and some local areas are substantially influenced. In addition, there are months during which BC and NBC post-processing produces significant differences in projected changes, such as summer runoff. Factor-controlled simulations indicate that BC post-processing of precipitation and temperature both substantially contribute to these differences at regional scales. We conclude that there are trade-offs between using BC climate data for offline CCI studies versus directly modeled climate data. These trade-offs should be considered when designing integrated modeling frameworks for specific applications; for example, BC may be more important when considering impacts on reservoir operations in mountainous watersheds than when investigating impacts on biogenic emissions and air quality, for which VOCs are a primary indicator
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