90 research outputs found

    Stellar Parameters for HD 69830, a Nearby Star with Three Neptune Mass Planets and an Asteroid Belt

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    We used the CHARA Array to directly measure the angular diameter of HD 69830, home to three Neptune mass planets and an asteroid belt. Our measurement of 0.674+/-0.014 milli-arcseconds for the limb-darkened angular diameter of this star leads to a physical radius of R_* = 0.9058±\pm0.0190 R\sun and luminosity of L* = 0.622+/-0.014 Lsun when combined with a fit to the spectral energy distribution of the star. Placing these observed values on an Hertzsprung-Russel (HR) diagram along with stellar evolution isochrones produces an age of 10.6+/-4 Gyr and mass of 0.863±\pm0.043 M\sun. We use archival optical echelle spectra of HD 69830 along with an iterative spectral fitting technique to measure the iron abundance ([Fe/H]=-0.04+/-0.03), effective temperature (5385+/-44 K) and surface gravity (log g = 4.49+/-0.06). We use these new values for the temperature and luminosity to calculate a more precise age of 7.5+/-Gyr. Applying the values of stellar luminosity and radius to recent models on the optimistic location of the habitable zone produces a range of 0.61-1.44 AU; partially outside the orbit of the furthest known planet (d) around HD 69830. Finally, we estimate the snow line at a distance of 1.95+/-0.19 AU, which is outside the orbit of all three planets and its asteroid belt.Comment: 5 pages, 3 figures, accepted to Ap

    The National COVID Cohort Collaborative (N3C): Rationale, design, infrastructure, and deployment.

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    OBJECTIVE: Coronavirus disease 2019 (COVID-19) poses societal challenges that require expeditious data and knowledge sharing. Though organizational clinical data are abundant, these are largely inaccessible to outside researchers. Statistical, machine learning, and causal analyses are most successful with large-scale data beyond what is available in any given organization. Here, we introduce the National COVID Cohort Collaborative (N3C), an open science community focused on analyzing patient-level data from many centers. MATERIALS AND METHODS: The Clinical and Translational Science Award Program and scientific community created N3C to overcome technical, regulatory, policy, and governance barriers to sharing and harmonizing individual-level clinical data. We developed solutions to extract, aggregate, and harmonize data across organizations and data models, and created a secure data enclave to enable efficient, transparent, and reproducible collaborative analytics. RESULTS: Organized in inclusive workstreams, we created legal agreements and governance for organizations and researchers; data extraction scripts to identify and ingest positive, negative, and possible COVID-19 cases; a data quality assurance and harmonization pipeline to create a single harmonized dataset; population of the secure data enclave with data, machine learning, and statistical analytics tools; dissemination mechanisms; and a synthetic data pilot to democratize data access. CONCLUSIONS: The N3C has demonstrated that a multisite collaborative learning health network can overcome barriers to rapidly build a scalable infrastructure incorporating multiorganizational clinical data for COVID-19 analytics. We expect this effort to save lives by enabling rapid collaboration among clinicians, researchers, and data scientists to identify treatments and specialized care and thereby reduce the immediate and long-term impacts of COVID-19

    "The End of Immortality!" Eternal Life and the Makropulos Debate

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    Responding to a well-known essay by Bernard Williams, philosophers (and a few theologians) have engaged in what I call “the Makropulos debate,” a debate over whether immortality—“living forever”—would be desirable for beings like us. Lacking a firm conceptual grounding in the religious contexts from which terms such as “immortality” and “eternal life” gain much of their sense, the debate has consisted chiefly in a battle of speculative fantasies. Having presented my four main reasons for this assessment, I examine an alternative and neglected conception, the idea of eternal life as a present possession, derived in large part from Johannine Christianity. Without claiming to argue for the truth of this conception, I present its investigation as exemplifying a conceptually fruitful direction of inquiry into immortality or eternal life, one which takes seriously the religious and ethical surroundings of these concepts

    Field Conference on the Tertiary and Pleistocene of Western Nebraska (Guide Book for the Ninth Field Conference of the Society of Vertebrate Paleontology)

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    This Field Conference is scheduled for five days, July 31-August 3 (main excursion) and August 4 (post-conference excursion), 1961. Its purpose is to consider recent work and problems in stratigraphy and vertebrate paleontology concerned with deposits ranging in age from Oligocene through Pleistocene, in western Nebraska. The Guide Book is the Ninth issued by sponsoring institutions for the Society of Vertebrate Paleontology (the others having been published in 1941, 1947, 1948, 1950, 1951, 1\u27953, 1956, and 1958). It thus commemorates the 20th Anniversary of the First Field Conference of the Society, as well as the 90th Anniversary of the establishment of the University of Nebraska State Museum (1871-1961). In addition to the discussion and itinerary provided by the authors, there is included a Faunal List of the Oreodonts from Nebraska, by C. Bertrand Schultz and Charles H. Falkenbach. Lloyd G. Tanner provided a road-log check and assisted with other arrangements; Harold J. Cook and A. L. Lugn also aided with arrangements for the Field Conference

    Swiss Exchange Rate Policy in the 1930s. Was the Delay in Devaluation Too High a Price to Pay for Conservatism?

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    In this paper we examine the experience of Switzerland’s devaluation in 1936. We ask the following questions: what were the issues at stake in the political debate? What was the cost to Switzerland of the delay in the franc devaluation? What would have been the costs and benefits of an earlier exchange rate policy? To answer these questions we construct a simple open economy macro model of the interwar Swiss economy. We then posit counterfactual scenarios of alternative exchange rate pegs in 1931 and 1933. Our simulations clearly show a significant and large increase in real economic activity. Copyright Springer Science+Business Media, LLC 2007Switzerland, Exchange rate policy, Devaluation, Gold bloc, Great depression, N14, N24,

    Beyond Belief: Prayer as Communication in Religious Information Seeking

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    Prayer role in information seeking has been largely neglected in LIS research. I propose that respondents understood prayer as communication with God. I compared their descriptions of prayer to God with research on interpersonal communication for information seeking. Prayer, for these respondents, met both cognitive and affective information needs. Le rôle de la prière dans la recherche d’information est un sujet largement négligé en bibliothéconomie et en science de l’information. L’auteur admet que les répondants perçoivent la prière comme un acte de communication avec Dieu. La description des prières a ensuite été comparée à la recherche sur les communications interpersonnelles dans une optique de recherche d’information. La prière, pour ces répondants, répondait à la fois à des besoins informationnels cognitifs et affectifs
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