106 research outputs found

    The Spatial and Emission Properties of the Large [O III] Emission Nebula Near M31

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    Drechsler et al. (2023) reported the unexpected discovery of a 1.5 degree long [O III] emission nebula 1.2 degrees southeast of the M31 nucleus. Here we present additional images of this large emission structure, called SDSO, along with radial velocity and flux measurements from low-dispersion spectra. Independent sets of [O III] images show SDSO to be composed of broad streaks of diffuse emission aligned NE-SW. Deep Hα\alpha images reveal no strong coincident emission suggesting a high [O III]/Hα\alpha ratio. We also find no other [O III] emission nebulosity as bright as SDSO within several degrees of M31 and no filamentary Hα\alpha emission connected to SDSO. Optical spectra taken along the arc's northern limb reveal [O III] λλ\lambda\lambda4959,5007 emissions matching the location and extent seen in our [O III] images. The heliocentric velocity of this [O III] nebulosity is −9.8±6.8-9.8 \pm 6.8 km s−1^{-1} with a peak surface brightness of (4±2)×10−18(4\pm2) \times 10^{-18} erg s−1^{-1} cm−2^{-2} arcsec−2^{-2} (∼\sim0.55 Rayleigh). We discuss SDSO as a possible unrecognized supernova remnant, a large and unusually nearby planetary nebula, a stellar bow shock nebula, or an interaction of M31's outer halo gas with high-velocity circumgalactic gas. We conclude that galactic origins for SDSO are unlikely and favor instead an extragalactic M31 halo--circumgalactic cloud interaction scenario, despite the nebula's low radial velocity. We then describe new observations that may help resolve the true nature and origin of this large nebulosity so close to M31 in the sky.Comment: 21 pages, 12 figure

    The Role of Practice Research Networks (PRN) in the Development and Implementation of Evidence: The Northern Improving Access to Psychological Therapies PRN Case Study

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    Practice research networks (PRNs) can support the implementation of evidence based practice in routine services and generate practice based evidence. This paper describes the structure, processes and learning from a new PRN in the Improving Access to Psychological Therapies programme in England, in relation to an implementation framework and using one study as a case example. Challenges related to: ethics and governance processes; communications with multiple stakeholders; competing time pressures and linking outcome data. Enablers included: early tangible outputs and impact; a collaborative approach; engaging with local research leads; clarity of processes; effective dissemination; and committed leadership

    Burial Depth and Stolon Internode Length Independently Affect Survival of Small Clonal Fragments

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    Disturbance can fragment plant clones into different sizes and unstabilize soils to different degrees, so that clonal fragments of different sizes can be buried in soils at different depths. As a short-term storage organ, solon internode may help fragmented clones of stoloniferous plants to withstand deeper burial in soils. We address (1) whether burial in soils decreases survival and growth of small clonal fragments, and (2) whether increasing internode length increases survival and growth of small fragments under burial. We conducted an experiment with the stoloniferous, invasive herb Alternanthera philoxeroides, in which single-node fragments with stolon internode of 0, 2, 4 and 8 cm were buried in soils at 0, 2, 4 and 8 cm depth, respectively. Increasing burial depth significantly reduced survival of the A. philoxeroides plants and increased root to shoot ratio and total stolon length, but did not change growth measures. Increasing internode length significantly increased survival and growth measures, but there was no interaction effect with burial depth on any traits measured. These results indicate that reserves stored in stolon internodes can contribute to the fitness of the A. philoxeroides plants subject to disturbance. Although burial reduced the regeneration capacity of the A. philoxeroides plants, the species may maintain the fitness by changing biomass allocation and stolon length once it survived the burial. Such responses may play an important role for A. philoxeroides in establishment and invasiveness in frequently disturbed habitats

    Une nouvelle station du Paléolithique moyen au Sud du village de Mont-les-Etrelles (Haute-Saône)

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    Claudel J., Sainty J. Une nouvelle station du Paléolithique moyen au Sud du village de Mont-les-Etrelles (Haute-Saône). In: Bulletin de la Société préhistorique française. Comptes rendus des séances mensuelles, tome 67, n°3, 1970. pp. 68-70
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