10,918 research outputs found

    Two-fluid magnetic island dynamics in slab geometry: I - Isolated islands

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    A set of reduced, 2-D, two-fluid, drift-MHD equations is derived. Using these equations, a complete and fully self-consistent solution is obtained for an isolated magnetic island propagating through a slab plasma with uniform but different ion and electron fluid velocities. The ion and electron fluid flow profiles around the island are uniquely determined, and are everywhere continuous. Moreover, the island phase-velocity is uniquely specified by the condition that there be zero net electromagnetic force acting on the island. Finally, the ion polarization current correction to the Rutherford island width evolution equation is evaluated, and found to be stabilizing provided that the anomalous perpendicular ion viscosity significantly exceeds the anomalous perpendicular electron viscosity

    Relaxing to a three dimensional brane junction

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    We suggest a mechanism which leads to 3+1 space-time dimensions. The Universe assumed to have nine spatial dimensions is regarded as a special nonlinear oscillatory system -- a kind of Einstein solid. There are p-brane solutions which manifest as phase oscillations separating different phase states. The presence of interactions allows for bifurcations of higher dimensional spaces to lower dimensional ones in the form of brane junctions. We argue this is a natural way to select lower dimensions.Comment: RevTex, 5 pages; version to appear in Europhys. Let

    IVOA Recommendation: SAMP - Simple Application Messaging Protocol Version 1.3

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    SAMP is a messaging protocol that enables astronomy software tools to interoperate and communicate. IVOA members have recognised that building a monolithic tool that attempts to fulfil all the requirements of all users is impractical, and it is a better use of our limited resources to enable individual tools to work together better. One element of this is defining common file formats for the exchange of data between different applications. Another important component is a messaging system that enables the applications to share data and take advantage of each other's functionality. SAMP builds on the success of a prior messaging protocol, PLASTIC, which has been in use since 2006 in over a dozen astronomy applications and has proven popular with users and developers. It is also intended to form a framework for more general messaging requirements

    The Distance to the Large Magellanic Cloud from the Eclipsing Binary HV2274

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    The distance to the Large Magellanic Cloud (LMC) is crucial for the calibration of the Cosmic Distance Scale. We derive a distance to the LMC based on an analysis of ground-based photometry and HST-based spectroscopy and spectrophotometry of the LMC eclipsing binary system HV2274. Analysis of the optical light curve and HST/GHRS radial velocity curve provides the masses and radii of the binary components. Analysis of the HST/FOS UV/optical spectrophotometry provides the temperatures of the component stars and the interstellar extinction of the system. When combined, these data yield a distance to the binary system. After correcting for the location of HV2274 with respect to the center of the LMC, we find d(LMC) = 45.7 +/- 1.6 kpc or DM(LMC) = 18.30 +/- 0.07 mag. This result, which is immune to the metallicity-induced zero point uncertainties that have plagued other techniques, lends strong support to the ``short'' LMC distance scale as derived from a number of independent methods.Comment: 6 pages, including 2 pages of figures. Newly available optical (B and V) photometry has revealed -- and allowed the elimination of -- a systematic error in the previously reported determination of E(B-V) for HV2274. The new result is E(B-V) = 0.12 mag (as compared to the value of 0.083 reported in the original submission) and produces a DECREASE in the distance modulus of HV2274 by 0.12 mag. ApJ Letters, in pres

    Integrated care and the working record

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    By default, many discussions and specifications of electronic health records or integrated care records often conceptualize the record as a passive information repository. This article presents data from a case study of work in a medical unit in a major metropolitan hospital. It shows how the clinicians tailored, re-presented and augmented clinical information to support their own roles in the delivery of care for individual patients. This is referred to as the working record: a set of complexly interrelated clinician-centred documents that are locally evolved, maintained and used to support delivery of care in conjunction with the more patient-centred chart that will be stored in the medical records department on the patient’s discharge. Implications are drawn for how an integrated care record could support the local tailorability and flexibility that underpin this working record and hence underpin practice

    Membership Drive Success: ALA/Alabama\u27s Support Staff Pilot Initiative

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    Many professional associations are grappling with membership challenges. Recently, the American Medical Association (AMA) adopted a strategy they termed the “member-centered” approach (Romano, 2004). One feature of this approach designed to boost membership is teaming with state and specialty societies. The American Medical Association believes that “future cooperation and collaboration with state associations is vital to any membership turnaround” (Romano, 2004, p. 11). This partnership makes good business sense. The American Library Association considers a cooperative venture with state associations as an important avenue to increase membership as well. Taking to heart the COPE recommendations and incorporating the idea of partnerships with state associations, ALA created a new membership option targeting library support staff at the state level. Alabama is the first state in which ALA will launch this cooperative endeavor. This article describes the joint staff membership initiative between a state association, the Alabama Library Association (ALLA), and the American Library Association – a unique pilot program already beginning to spread nationwide

    21st century fisheries management: a spatio-temporally explicit tariff-based approach combining multiple drivers and incentivising responsible fishing

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    Abstract Kraak, S. B. M., Reid, D. G., Gerritsen, H. D., Kelly, C. J., Fitzpatrick, M., Codling, E. A., and Rogan, E. 2012. 21st century fisheries management: a spatio-temporally explicit tariff-based approach combining multiple drivers and incentivising responsible fishing. – ICES Journal of Marine Science, 69: 590–601. Traditionally fisheries management has focused on biomass and mortality, expressed annually and across large management units. However, because fish abundance varies at much smaller spatio-temporal scales, fishing mortality can potentially be controlled more effectively if managed at finer scale. The ecosystem approach requires more indicators at finer scales as well. Incorporating ecosystem targets would need additional management tools with potentially conflicting results. We present a simple, integrated, management approach that provides incentives for “good behaviour”. Fishers would be given a number of fishing-impact credits, called real-time incentives (RTIs), to spend according to spatio-temporally varying tariffs per fishing day. RTI quotas and tariffs could be based on commercial stocks and ecosystem targets. Fishers could choose how to spend their RTIs, e.g. by limited fishing in high-catch or sensitive areas or by fishing longer in lower-catch or less sensitive areas. The RTI system does not prescribe and forbid, but instead allows fishers to fish wherever and whenever they want; ecosystem costs are internalized and fishers have to take them into account in their business decisions. We envisage no need for traditional landings or catch quotas for the fleets while operating under the scheme. The approach could facilitate further devolution of responsibility to industry.</jats:p

    Protocol for the United Kingdom Rotator Cuff Study (UKUFF) : a randomised controlled trial of open and arthroscopic rotator cuff repair

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    This project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02). J. L. Rees has received a grant from Oxford University which is related to this paper. J. Dawson reports that Oxford University has received a grant from HTA which is related to this paper, as well as a study grant.Peer reviewedPublisher PD

    Epidemiological tracing of Batrachochytrium salamandrivorans identifies widespread infection and associated mortalities in private amphibian collections

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    The amphibian chytrid fungus Batrachochytrium salamandrivorans (Bsal) infects newts and salamanders (urodele amphibians), in which it can cause fatal disease. This pathogen has caused dramatic fire salamander population declines in Belgium, the Netherlands and Germany since its discovery in 2010. Thought to be native to Asia, it has been hypothesised that Bsal was introduced to Europe with the importation of infected amphibians for the commercial pet trade. Following the discovery of Bsal in captive amphibians in the United Kingdom in 2015, we used contact-tracing to identify epidemiologically-linked private amphibian collections in Western Europe. Of 16 linked collections identified, animals were tested from 11 and urodeles tested positive for Bsal in seven, including the identification of the pathogen in Spain for the first time. Mortality of Bsal-positive individuals was observed in five collections. Our results indicate that Bsal is likely widespread within the private amphibian trade, at least in Europe. These findings are important for informing policy regarding Bsal control strategies
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