428 research outputs found
Pacific Seascapes, Canoe Performance, and a Review of Lapita Voyaging with Regard to Theories of Migration
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
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
High precision radial velocity (RV) measurements spanning the years
1980.8--2000.0 are presented for the nearby (3.22 pc) K2 V star Eri.
These data, which represent a combination of six independent data sets taken
with four different telescopes, show convincing variations with a period of
7 yrs. A least squares orbital solution using robust estimation
yields orbital parameters of period, = 6.9 yrs, velocity -amplitude
19 {\ms}, eccentricity 0.6, projected companion mass sin = 0.86
, and semi-major axis 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
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
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
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
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
Geoffrey Irwin\u27s response to the Book Review Forum on The Prehistoric Exploration and Colonisation of the Pacific
Toward a Revised 4.2 No-Contact Rule
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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