3,266 research outputs found

    Multi-region relaxed magnetohydrodynamics with anisotropy and flow

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    We present an extension of the multi-region relaxed magnetohydrodynamics (MRxMHD) equilibrium model that includes pressure anisotropy and general plasma flows. This anisotropic extension to our previous isotropic model is motivated by Sun and Finn's model of relaxed anisotropic magnetohydrodynamic equilibria. We prove that as the number of plasma regions becomes infinite, our anisotropic extension of MRxMHD reduces to anisotropic ideal MHD with flow. The continuously nested flux surface limit of our MRxMHD model is the first variational principle for anisotropic plasma equilibria with general flow fields.Comment: 11 pages, 2 figures. arXiv admin note: text overlap with arXiv:1401.307

    GOLD in Practice: Chronic Obstructive Pulmonary Disease Treatment and Management in the Primary Care Setting

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    Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality. Early detection and appropriate treatment and management of COPD can lower morbidity and perhaps mortality. Clinicians in the primary care setting provide the majority of COPD care and are pivotal in the diagnosis and management of COPD. In this review, we provide an overview of the Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2020 report, with a focus on the management of COPD in the primary care setting. We discuss the pathophysiology of COPD; describe COPD risk factors, signs, and symptoms that may facilitate earlier diagnosis of COPD; and reinforce the importance of spirometry use in establishing the diagnosis of COPD. Disease monitoring, as well as a review of the 2020 GOLD treatment recommendations, is also discussed. Patients and families are important partners in COPD management; therefore, we outline simple steps that may assist them in caring for those affected by COPD. Finally, we discuss nonpharmacological treatment options for COPD, COPD monitoring tools that may aid in the evaluation of disease progression and response to therapy, and the importance of developing a COPD action plan on an individualized basis

    Quantum kinetic theory model of a continuous atom laser

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    We investigate the feasible limits for realising a continuously evaporated atom laser with high-temperature sources. A plausible scheme for realising a truly continuous atom laser is to outcouple atoms from a partially condensed Bose gas, whilst continuously reloading the system with non-condensed thermal atoms and performing evaporative cooling. Here we use quantum kinetic theory to model this system and estimate feasible limits for the operation of such a scheme. For sufficiently high temperatures, the figure of merit for the source is shown to be the phase-space flux. The dominant process limiting the usage of sources with low phase-space flux is the three-body loss of the condensed gas. We conclude that certain double-magneto-optical trap (MOT) sources may produce substantial mean condensate numbers through continuous evaporation, and provide an atom laser source with a narrow linewidth and reasonable flux.Comment: 28 pages, 5 figure

    Evaluation of a Year-Round Grazing System: Winter Progress Report

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    The winter component of a year-round grazing system involving grazing of corn crop residues followed by grazing stockpiled grass legume forages was compared at the McNay Research Farm with that of the winter component of a minimal land system that maintained cows in drylot,. In the summer of 1995, two cuttings of hay were harvested from two 15-acre fields containing “Johnston” endophyte-free tall fescue and red clover, and two cuttings of hay were taken from two 15-acre fields of smooth bromegrass and red clover. Hay yields were 4,236 and 4,600 pounds of dry matter per acre for the tall fescue--red clover and smooth bromegrass--red clover. Following grain harvest four 7.5-acre fields containing corn crop residue were stocked with cows at midgestation at an allowance of 1.5 acres per cow. Forage yields at the initiation of corn crop grazing were 3,766pounds of dry matter per acre for corn crop residue, 1,748 pounds for tall fescue--red clover, and 1,.880 pounds for smooth bromegrass--red clover. Corn crop residues and stockpiled forages were grazed in a strip stocking system. For comparison, 20 cows were placed in two drylots simultaneously to the initiation of corn crop grazing where they remained throughout the winter and spring grazing seasons. Cows maintained in drylot or grazing corn crop residue and stockpiled forages were supplemented with hay as large round bales to maintain a body condition score of five. No seasonal differences in body weight and body condition were observed between grazing cows or cows maintained in drylot, but grazing cows required 87% and 84% less harvested hay than cows in drylot during the winter and spring respectively. Because less hay was needed to maintain grazing cows, an excess of 11,905 and 12,803 pounds of hay dry matter per cow remained in the year-round grazing system. During corn crop grazing, organic matter yield decreased at 27.3 pounds of organic matter per day from grazed areas of corn crop residue. Organic matter losses due to weathering were 9.4, 12.9, and 15.8 pounds per day in corn crop residue, tall fescue-red clover and smooth bromegrass-red clover. Organic matter losses from grazed and ungrazed areas during stockpiled grazing were 7.3 and 6.9 for tall fescue--red clover and 2.1, 2.9 for smooth bromegrass--red clover

    Evaluation of a Year-Round Grazing System: Summer Cow-Calf Progress Report

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    A comparison was made between two different summer grazing systems. One system was the summer component of a year-round grazing system, involving the rotational stocking of smooth bromegrass--orchardgrass--birdsfoot trefoil pastures and winter stockpiles pastures with cowcalf pairs co-grazing with stocker yearlings at .75 animal units per acre. That system was compared with a minimal land system involving the rotational stocking of smooth bromegrass--orchardgrass-- birdsfoot trefoil summer pastures with cow-calf pairs grazing at .64 animal units per acre and hay removal from 25% of the pasture. Stocker yearlings or hay removal were used as management tools to remove excess forage and optimize forage quality. Hay was removed once from three fourths of the winter stockpiled pastures and one fourth of the allocated summer pastures. Cow-calf pairs grazing in the year-round system utilized on fourth of the winter stockpile pastures due to lack of forage, whereas cow-calf pairs grazing with hay removal were supplemented with harvested hay for two weeks during the summer. Grazing system did not affect cow body weight, condition score, or daily calf weight gain. Growing animal production per acre was affected by grazing system, with the minimal land system having a higher production level

    Area-level incarceration and STI risk among a cohort of justice-involved adolescents and adults

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    Background: Living in areas of high incarceration is associated with increased risk of STI; however, STI risk with respect to both this area-level exposure and an individual’s involvement with the justice system is not known. Objective: Among individuals before and after arrest or incarceration, assess the association between area-level incarceration rates and risk of chlamydia, gonorrhea, or syphilis. Methods: Retrospective cohort study of individuals living in Marion County (Indianapolis), Indiana who were arrested or in jail, prison, juvenile detention, or juvenile prison between 2005-2008 (N=97,765). Area-level incarceration exposure was defined by the proportion of person-days incarcerated among the total population*365 within a census block group. A 1-year period was assessed before and after a randomly-selected arrest/incarceration per person. Multivariable logistic regression, controlling for age, race, STI history, and year, was performed to assess chlamydia, gonorrhea, or syphilis risk by quartile area-level incarceration exposure, adjusting for individual clustering and stratifying by gender. Results: Area-level incarceration was associated with increased odds of each STI, with a dose response relationship particularly among those with an arrest or jail stay. Women with a history of arrest or jail/prison stay and living in high incarceration areas had higher odds of STI, compared to men with comparable incarceration history and living in similar areas

    Enabling hotspot detection and public health response to the COVID-19 pandemic

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    INTRODUCTION: Public-facing maps of COVID-19 cases, hospital admissions, and deaths are commonly displayed at the state, county, and zip code levels, and low case counts are suppressed to protect confidentiality. Public health authorities are tasked with case identification, contact tracing, and canvasing for educational purposes during a pandemic. Given limited resources, authorities would benefit from the ability to tailor their efforts to a particular neighborhood or congregate living facility. METHODS: We describe the methods of building a real-time visualization of patients with COVID-19-positive tests, which facilitates timely public health response to the pandemic. We developed an interactive street-level visualization that shows new cases developing over time and resolving after 14 days of infection. Our source data included patient demographics (ie, age, race and ethnicity, and sex), street address of residence, respiratory test results, and date of test. RESULTS: We used colored dots to represent infections. The resulting animation shows where new cases developed in the region and how patterns changed over the course of the pandemic. Users can enlarge specific areas of the map and see street-level detail on residential location of each case and can select from demographic overlays and contour mapping options to see high-level patterns and associations with demographics and chronic disease prevalence as they emerge. CONCLUSIONS: Before the development of this tool, local public health departments in our region did not have a means to map cases of disease to the street level and gain real-time insights into the underlying population where hotspots had developed. For privacy reasons, this tool is password-protected and not available to the public. We expect this tool to prove useful to public health departments as they navigate not only COVID-19 pandemic outcomes but also other public health threats, including chronic diseases and communicable disease outbreaks
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