22,597 research outputs found

    Homoclinic snaking in bounded domains

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    Homoclinic snaking is a term used to describe the back and forth oscillation of a branch of time-independent spatially localized states in a bistable, spatially reversible system as the localized structure grows in length by repeatedly adding rolls on either side. On the real line this process continues forever. In finite domains snaking terminates once the domain is filled but the details of how this occurs depend critically on the choice of boundary conditions. With periodic boundary conditions the snaking branches terminate on a branch of spatially periodic states. However, with non-Neumann boundary conditions they turn continuously into a large amplitude filling state that replaces the periodic state. This behavior, shown here in detail for the Swift-Hohenberg equation, explains the phenomenon of “snaking without bistability”, recently observed in simulations of binary fluid convection by Mercader, Batiste, Alonso and Knobloch (preprint)

    Radio-Continuum Observations Of Small, Radially Polarised Supernova Remnant J0519-6902 In The Large Magellanic Cloud

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    We report on new Australian Telescope Compact Array (ATCA) observations of SNR J0519-6902. The Supernova Remnant (SNR) is small in size (~8 pc) and exhibits a typical SNR spectrum of alpha = -0.53 +- 0.07, with steeper spectral indices found towards the northern limb of the remnant. SNR J0519-6902 contains a low level of radially orientated polarisation at wavelengths of 3 & 6 cm, which is characteristic of younger SNRs. A fairly strong magnetic field was estimated of ~171 microG. The remnant appears to be the result of a typical Type Ia supernovae, sharing many properties as another small and young Type Ia LMC SNR, J0509-6731.Comment: 10 pages 7 figures, submitted to Serbian Astronomical Journa

    Conceptual analyses of extensible booms to support a solar sail

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    Extensible booms which could function as the diagonal spars and central mast of an 800 meter square, non-rotating Solar Sailing Vehicle were conceptually designed and analyzed. The boom design concept that was investigated is an extensible lattice boom which is stowed and deployed by elastically coiling and uncoiling its continuous longerons. The seven different free-span lengths in each spar which would minimize the total weights of the spars and mast were determined. Boom weights were calculated by using a semi-empirical formulation which related the overall weight of a boom to the weight of its longerons

    Improving the quality of mental health services using patient outcome data: Making the most of HoNOS

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    Efforts to assess and improve the quality of mental health services are often hampered by a lack of information on patient outcomes. Most mental health services in England have been routinely collecting Health of the Nation Outcome Scales (HoNOS) data for some time. In this article we illustrate how clinical teams have used HoNOS data to identify areas where performance could be improved. HoNOS data have the potential to give clinical teams the information they need to assess the quality of care they deliver, as well as develop and test initiatives aimed at improving the services they provide

    Radio-continuum study of Large Magellanic Cloud Supernova Remnant J0509-6731

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    We present a detailed study of Australia Telescope Compact Array (ATCA) observations (λ\lambda = 20, 13, 6 & 3~cm) of supernova remnant (SNR) J0509--6731 in the Large Magellanic Cloud (LMC). The remnant has a ring morphology with brightened regions towards the south-western limb. We also find a second brightened inner ring which is only seen in the radio-continuum. The SNR is almost circular, with a diameter ranging from 7 to 8~pc, and a steep radio spectral index between 36 and 3~cm of α=0.73±0.02\alpha=-0.73\pm0.02, which is characteristic of younger SNRs. We also report detection of radially orientated polarisation across the remnant at 6~cm, with a mean fractional polarisation level of PP\cong~(26~±\pm~13)%. We find the magnetic field (\sim168~μ\muG) and ΣD\Sigma - D (Σ=\Sigma = 1.1×10191.1\times 10^{-19}~W m2^{-2}~Hz1^{-1}~sr1^{-1} , D=D= 7.35~pc) to be consistent with other young remnants

    SMC SMP 24: A newly radio-detected planetary nebula in the small magellanic cloud

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    In this paper we report new radio-continuum detection of an extragalactic PN: SMC SMP 24. We show the radio-continuum image of this PN and present the measured radio data. The newly reduced radio observations are consistent with the multi-wavelength data and derived parameters found in the literature. SMC SMP 24 appear to be a young and compact PN, optically thick at frequencies below 2 GHz.Comment: accepted for publication in Serbian Astronomical Journa

    Radio Continuum Study of Supernova Remnants in the Large Magellanic Cloud - SNR J0519-6926

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    We present the results of new high resolution ATCA observations of SNR J0519-6926. We found that this SNR exhibits a typical "horseshoe" appearance with alpha = -0.55 +- 0.08 and D=28+-1 pc. No polarization (or magnetic fields) are detected to a level of 1%. This is probably due to a relatively poor sampling of the uv plane caused be observing in "snap-shot" mode.Comment: 6 pages 4 figures, to be published in Serbian Astronomical Journa

    Multifrequency Observations of One of the Largest Supernova Remnants in the Local Group of Galaxies, LMC - SNR J0450-709

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    We present the results of new Australia Telescope Compact Array (ATCA) observations of one of the largest supernova remnants, SNR J0450-709, in the Local Group of galaxies. We found that this Large Magellanic Cloud (LMC) ob ject exhibits a typical morphology of an old supernova remnant (SNR) with diameter D=102x75+-1 pc and radio spectral index alpha=-0.43+-0.06. Regions of high polarisation were detected with peak value of ~40%.Comment: 7 pages, 4 figures, accepted for publication in Serbian Astronomical Journa
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