7,184 research outputs found

    Long term frequency stability analysis of the GPS NAVSTAR 6 Cesium clock

    Get PDF
    Time domain measurements, taken between the NAVSTAR 6 Spacecraft Vehicle (SV) and the Vandenberg Global Positioning System (GPS) Monitor Site, by a pseudo random noise receiver, were collected over an extended period of time and analyzed to estimate the long term frequency stability of the NAVSTAR 6 onboard frequency standard, referenced to the Vandenberg MS frequency standard. The technique employed separates the clock offset from the composite signal by first applying corrections for equipment delays, ionospheric delay, tropospheric delay, Earth rotation and the relativistic effect. The data are edited and smoothed using the predicted SV ephemeris to calculate the geometric delay. Then all available passes from each of the four GPS monitor stations, are collected at 1-week intervals and used to calculate the NAVSTAR orbital elements. The procedure is then completed by subtracting the corrections and the geometric delay, using the final orbital elements, from the composite signal, thus leaving the clock offset and random error

    Preliminary catalog of pictures taken on the lunar surface during the Apollo 16 mission

    Get PDF
    A catalog of all pictures taken from the lunar module or the lunar surface during the Apollo 16 lunar stay is presented. The tabulations are arranged for the following specific uses: (1) given the number of a particular frame, find its location in the sequence of lunar surface activity, the station from which it was taken and the subject matter of the picture; (2) given a particular location or activity within the sequence of lunar surface activity, find the pictures taken at that time and their subject matter; and (3) given a sample number from the voice transcript listed, find the designation assigned to the same sample by the lunar receiving laboratory

    The Rachel Carson Letters and the Making of Silent Spring

    Get PDF
    Environment, conservation, green, and kindred movements look back to Rachel Carson’s 1962 book Silent Spring as a milestone. The impact of the book, including on government, industry, and civil society, was immediate and substantial, and has been extensively described; however, the provenance of the book has been less thoroughly examined. Using Carson’s personal correspondence, this paper reveals that the primary source for Carson’s book was the extensive evidence and contacts compiled by two biodynamic farmers, Marjorie Spock and Mary T. Richards, of Long Island, New York. Their evidence was compiled for a suite of legal actions (1957-1960) against the U.S. Government and that contested the aerial spraying of dichlorodiphenyltrichloroethane (DDT). During Rudolf Steiner’s lifetime, Spock and Richards both studied at Steiner’s Goetheanum, the headquarters of Anthroposophy, located in Dornach, Switzerland. Spock and Richards were prominent U.S. anthroposophists, and established a biodynamic farm under the tutelage of the leading biodynamics exponent of the time, Dr. Ehrenfried Pfeiffer. When their property was under threat from a government program of DDT spraying, they brought their case, eventually lost it, in the process spent US$100,000, and compiled the evidence that they then shared with Carson, who used it, and their extensive contacts and the trial transcripts, as the primary input for Silent Spring. Carson attributed to Spock, Richards, and Pfeiffer, no credit whatsoever in her book. As a consequence, the organics movement has not received the recognition, that is its due, as the primary impulse for Silent Spring, and it is, itself, unaware of this provenance

    National trends in retreatment of HCV due to reinfection or treatment failure in Australia

    Full text link
    Background & Aims: Population-level uptake of direct-acting antiviral (DAA) treatment for hepatitis C virus (HCV) infection, including retreatment, can be estimated through administrative pharmaceutical dispensation data. However, the reasons for retreatment are not captured in these data. We developed a machine learning model to classify retreatments as reinfection or treatment failure at a national level. Methods: Retreatment data from the REACH-C cohort (n = 10,843 treated with DAAs; n = 320 retreatments with known reason), were used to train a random forest model. Nested cross validation was undertaken to assess model performance and to optimise hyperparameters. The model was applied to data on DAA retreatment dispensed during 2016-2021 in Australia, to identify the reason for retreatment (treatment failure or reinfection). Results: Average predictive accuracy, precision, sensitivity, specificity and F1-score for the model were 96.3%, 96.5%, 96.3%, 96.3% and 96.3%, respectively. Nationally, 95,272 individuals initiated DAAs, with treatment uptake declining from 32,454 in 2016 to 6,566 in 2021. Of those treated, 6,980 (7%) were retreated. Our model classified 51.8% (95% CI 46.7–53.6%; n = 3,614) of cases as reinfection and 48.2% (95% CI 46.4–53.3%; n = 3,366) as treatment failure. Retreatment for reinfection increased steadily over the study period from 14 in 2016 to 1,092 in 2020, stabilising in 2021. Retreatment for treatment failure increased from 73 in 2016 to 1,077 in 2019, then declined to 515 in 2021. Among individuals retreated for treatment failure, 50% had discontinued initial treatment. Conclusions: We used a novel methodology with high classification accuracy to evaluate DAA retreatment patterns at a national level. Increases in retreatment uptake for treatment failure corresponded to the availability of pangenotypic and salvage regimens. Increasing retreatment uptake for reinfection likely reflects increasing reinfection incidence. Impact and implications: This study used machine learning methodologies to analyse national administrative data and characterise trends in HCV retreatment due to reinfection and treatment failure. Retreatment for reinfection increased over time, reflecting increasing numbers of people at risk for reinfection following HCV cure. Increased retreatment for treatment failure corresponded to the availability of pangenotypic and salvage DAA regimens. The findings of this study can be used by public health agencies and policy makers to guide and assess HCV elimination strategies, while the novel methodology for monitoring trends in HCV retreatment has the potential to be used in other settings, and health conditions

    Correlations, fluctuations and stability of a finite-size network of coupled oscillators

    Full text link
    The incoherent state of the Kuramoto model of coupled oscillators exhibits marginal modes in mean field theory. We demonstrate that corrections due to finite size effects render these modes stable in the subcritical case, i.e. when the population is not synchronous. This demonstration is facilitated by the construction of a non-equilibrium statistical field theoretic formulation of a generic model of coupled oscillators. This theory is consistent with previous results. In the all-to-all case, the fluctuations in this theory are due completely to finite size corrections, which can be calculated in an expansion in 1/N, where N is the number of oscillators. The N -> infinity limit of this theory is what is traditionally called mean field theory for the Kuramoto model.Comment: 25 pages (2 column), 12 figures, modifications for resubmissio

    Sex and Gender-Based Women\u27s Health: A Practical Guide for Primary Care - A Resource for Learning and Teaching

    Get PDF
    TOP WINNER Background: Patients expect comprehensive, gender-specific care; yet studies reveal that few residency programs in internal medicine provide dedicated training in women’s health and gender-based medicine. Further, graduates are unable to demonstrate competency to care for female and gender-diverse patients. Objectives: To produce a sex and gender-based women’s health curriculum, written explicitly for primary care providers to guide the care of women and gender-diverse patients, and to be used as a curriculum to educate learners. Methods: In collaboration with Springer Nature, development of this online and inprint textbook began in 2017. Topics were chosen with input from women’s health experts and are tailored to gender-based conditions commonly evaluated, diagnosed, and/or managed in the primary care setting. Authors were then recruited nationally for each topic. Using evidenced-based medicine principles, chapters were formatted for consistency to include the epidemiology, physiology/pathophysiology, clinical manifestations, differential diagnosis, diagnostic approach, and treatment for each topic, when appropriate. Each chapter has clear, measurable learning objectives, summary statements, and multiplechoice questions with annotated answers to check understanding and help earn CME and MOC credit. With 39 chapters and \u3e600 pages, sections are comprehensive and include Breast and Gynecologic Health and Disease, Obstetric Medicine, Chronic Pain Disorders, Mental Health and Trauma, LGBTQ Health, Common Medical Conditions (osteoporosis, cardiovascular disease), and Foundations of Women’s Health, which highlights the history, disparities, and future of women’s and gender-based healthcare. Conclusions/Impact: This is the first comprehensive curricular resource written by clinical women’s health physicians, using the most up-to-date evidence, clinical guidelines, expert opinion, and clinical pearls. Our goal is to provide a guide that can serve as a quick point-of-care clinical reference for a specific topic or as a longitudinal curriculum for learners in any primary care discipline, especially programs where women’s health and gender-specific curricula and champions are sparse.https://jdc.jefferson.edu/sexandgenderhealth/1030/thumbnail.jp

    Institutional and policy issues in the management of fisheries and coastal resources in Cambodia

    Get PDF
    Fishery management, Governments, Fishery policies, Resource conservation, Resource management, Cambodia,

    The General Correlation Function in the Schwinger Model on a Torus

    Full text link
    In the framework of the Euclidean path integral approach we derive the exact formula for the general N-point chiral densities correlator in the Schwinger model on a torusComment: 17 pages, misprints corrected, references adde

    Multisphalerons in the Weinberg-Salam Theory

    Full text link
    We construct multisphaleron solutions in the Weinberg-Salam theory. The multisphaleron solutions carry Chern-Simons charge n/2n/2, where nn is an integer, counting the winding of the fields in the azimuthal angle. The well-known sphaleron has n=1n=1. The multisphalerons possess axial symmetry and parity reflection symmetry. We vary the Higgs mass and the mixing angle. For small nn the energies of the multisphalerons are on the order of nn times the energy of the sphaleron and their magnetic dipole moments are on the order of nn times the magnetic dipole moment of the sphaleron.Comment: 18 pages, latex, 17 figures in uuencoded postscript files. THU-94/1

    Pairing in low-density Fermi gases

    Get PDF
    We consider pairing in a dilute system of Fermions with a short-range interaction. While the theory is ill-defined for a contact interaction, the BCS equations can be solved in the leading order of low-energy effective field theory. The integrals are evaluated with the dimensional regularization technique, giving analytic formulas relating the pairing gap, the density, and the energy density to the two-particle scattering length.Comment: 12 pages, 2 EPS-figures, uses psfig.sty, eq.(9) correcte
    • …
    corecore