428 research outputs found

    Pacific Seascapes, Canoe Performance, and a Review of Lapita Voyaging with Regard to Theories of Migration

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    The first part of this paper establishes in a general kind of way that the domain or seascape that Lapita sailors operated in was more demanding than that of Wallacea and Near Oceania, but markedly less so than that negotiated later by East Polynesians. The second part takes a look at the form and performance of canoes, the possible nature of Lapita craft, and suggests ways to improve modern estimates of prehistoric performance by mechanical and mathematical modeling. The third part considers the practicalities of sailing in the Lapita domain; it argues that the dispersal of Lapita was in a selected direction rather than a random one, and offers a glimpse of how these ambitious but relatively cautious sailors learned to navigate. The final aim of the paper is to summarize three theories of migration, which support each other in some respects, but which differ in others-especially in their views of prehistoric canoe performance. KEYWORDS: Pacific Ocean, Lapita, seascapes, canoe performance, colonization

    Combined horizontal and vertical integration of care: a goal of practice-based commissioning

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    Practice-based commissioning (PBC) in the UK is intended to improve both the vertical and horizontal integration of health care, in order to avoid escalating costs and enhance population health. Vertical integration involves patient pathways to treat named medical conditions that transcend organisational boundaries and connect communitybased generalists with largely hospital-sited specialists, whereas horizontal integration involves peerbased and cross-sectoral collaboration to improve overall health. Effective mechanisms are now needed to permit ongoing dialogue between the vertical and horizontal dimensions to ensure that medical and nonmedical care are both used to their best advantage. This paper proposes three different models for combining vertical and horizontal integration – each is a hybrid of internationally recognised ideal types of primary care organisation. Leaders of PBC should consider a range of models and apply them in ways that are relevant to the local context. General practitioners, policy makers and others whose job it is to facilitate horizontal and vertical integration must learn to lead such combined approaches to integration if the UK is to avoid the mistakes of the USA in over-medicalising health issues

    Evidence for a Long-period Planet Orbiting Epsilon Eridani

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    High precision radial velocity (RV) measurements spanning the years 1980.8--2000.0 are presented for the nearby (3.22 pc) K2 V star ϵ\epsilon Eri. These data, which represent a combination of six independent data sets taken with four different telescopes, show convincing variations with a period of \approx 7 yrs. A least squares orbital solution using robust estimation yields orbital parameters of period, PP = 6.9 yrs, velocity KK-amplitude == 19 {\ms}, eccentricity ee == 0.6, projected companion mass MM sin ii = 0.86 MJupiterM_{Jupiter}, and semi-major axis a2a_2 == 3.3 AU. Ca II H&K S-index measurements spanning the same time interval show significant variations with periods of 3 and 20 yrs, yet none at the RV period. If magnetic activity were responsible for the RV variations then it produces a significantly different period than is seen in the Ca II data. Given the lack of Ca II variation with the same period as that found in the RV measurements, the long-lived and coherent nature of these variations, and the high eccentricity of the implied orbit, Keplerian motion due to a planetary companion seems to be the most likely explanation for the observed RV variations. The wide angular separation of the planet from the star (approximately 1 arc-second) and the long orbital period make this planet a prime candidate for both direct imaging and space-based astrometric measurements.Comment: To appear in Astrophysical Journal Letters. 9 pages, 2 figure

    Final Project 3.0: A Student Virtual World Conference on the Future of Collaboration

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    There is currently little research of any kind on enterprise virtual worlds or using these collaborative tool ecosystems for geographically distributed education in organizational studies. In 2013, a group of multidisciplinary graduate students created and executed a conference in a 3D virtual world as a class project. The topics presented in the conference were crowdsourcing and mobile virtual worlds, but the overall experience resulted in learning well beyond those topics. The project team encountered a significant learning curve over planning and executing in person meetings as well as technical challenges that would threaten the success of the project. This paper describes the end-to-end process taken by the team to plan and execute the conference, and shows the challenges, successes, and the lessons learned that can be applied to future conferences in 3D virtual worlds, which promise incredible potential for improving collaboration across businesses

    Characterizing the Cool KOIs II. The M Dwarf KOI-254 and its Hot Jupiter

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    We report the confirmation and characterization of a transiting gas giant planet orbiting the M dwarf KOI-254 every 2.455239 days, which was originally discovered by the Kepler mission. We use radial velocity measurements, adaptive optics imaging and near infrared spectroscopy to confirm the planetary nature of the transit events. KOI-254b is the first hot Jupiter discovered around an M-type dwarf star. We also present a new model-independent method of using broadband photometry to estimate the mass and metallicity of an M dwarf without relying on a direct distance measurement. Included in this methodology is a new photometric metallicity calibration based on J-K colors. We use this technique to measure the physical properties of KOI-254 and its planet. We measure a planet mass of Mp = 0.505 Mjup, radius Rp = 0.96 Rjup and semimajor axis a = 0.03 AU, based on our measured stellar mass Mstar = 0.59 Msun and radius Rstar = 0.55 Rsun. We also find that the host star is metal-rich, which is consistent with the sample of M-type stars known to harbor giant planets.Comment: AJ accepted (in press

    The Transit Light Curve Project. X. A Christmas Transit of HD 17156b

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    Photometry is presented of the Dec. 25, 2007 transit of HD 17156b, which has the longest orbital period and highest orbital eccentricity of all the known transiting exoplanets. New measurements of the stellar radial velocity are also presented. All the data are combined and integrated with stellar-evolutionary modeling to derive refined system parameters. The planet's mass and radius are found to be 3.212_{-0.082}^{+0.069} Jupiter masses and 1.023_{-0.055}^{+0.070} Jupiter radii. The corresponding stellar properties are 1.263_{-0.047}^{+0.035} solar masses and 1.446_{-0.067}^{+0.099} solar radii. The planet is smaller by 1 sigma than a theoretical solar-composition gas giant with the same mass and equilibrium temperature, a possible indication of heavy-element enrichment. The midtransit time is measured to within 1 min, and shows no deviation from a linear ephemeris (and therefore no evidence for orbital perturbations from other planets). We provide ephemerides for future transits and superior conjunctions. There is an 18% chance that the orbital plane is oriented close enough to edge-on for secondary eclipses to occur at superior conjunction. Observations of secondary eclipses would reveal the thermal emission spectrum of a planet that experiences unusually large tidal heating and insolation variations.Comment: To appear in ApJ [26 pages

    Improved annotation of 3' untranslated regions and complex loci by combination of strand-specific direct RNA sequencing, RNA-seq and ESTs

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    The reference annotations made for a genome sequence provide the framework for all subsequent analyses of the genome. Correct annotation is particularly important when interpreting the results of RNA-seq experiments where short sequence reads are mapped against the genome and assigned to genes according to the annotation. Inconsistencies in annotations between the reference and the experimental system can lead to incorrect interpretation of the effect on RNA expression of an experimental treatment or mutation in the system under study. Until recently, the genome-wide annotation of 3-prime untranslated regions received less attention than coding regions and the delineation of intron/exon boundaries. In this paper, data produced for samples in Human, Chicken and A. thaliana by the novel single-molecule, strand-specific, Direct RNA Sequencing technology from Helicos Biosciences which locates 3-prime polyadenylation sites to within +/- 2 nt, were combined with archival EST and RNA-Seq data. Nine examples are illustrated where this combination of data allowed: (1) gene and 3-prime UTR re-annotation (including extension of one 3-prime UTR by 5.9 kb); (2) disentangling of gene expression in complex regions; (3) clearer interpretation of small RNA expression and (4) identification of novel genes. While the specific examples displayed here may become obsolete as genome sequences and their annotations are refined, the principles laid out in this paper will be of general use both to those annotating genomes and those seeking to interpret existing publically available annotations in the context of their own experimental dataComment: 44 pages, 9 figure

    Toward a Revised 4.2 No-Contact Rule

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    Model Rule of Professional Conduct 4.2, in effect in substantially similar form in all U.S. jurisdictions, generally forbids a lawyer from contacting a person represented by another lawyer unless that lawyer consents or the contact is authorized by law. Our thesis is that as conceptualized and applied, this Rule is overbroad and ambiguous in important respects. After illustrating and explaining these shortcomings, we propose reform to Rule 4.2 to better implement its intended purpose. Specifically, we propose modifications to the text of the Rule that: (i) clarify the meaning of the authorized by law exception, (2) articulate new exceptions to avoid unjust applications, (3) revise the test for application of the Rule in the organizational context, and (4) offer guidelines for communications that occur under any of the Rule\u27s exceptions. We then propose modifications to the Rule\u27s comments that explain and elaborate on these modifications. Together, our proposed changes aim to implement Rule 4.2\u27S proper purpose-protecting the lawyer client relationship, while acknowledging and balancing competing duties and interests
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