4,292 research outputs found

    The rectus sling to prevent loop colostomy retraction: a case series

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    Diverting stomas are being used increasingly in the management of rectal cancer, particularly with low anterior resection following neoadjuvant therapy. We describe a simple anchorage method for loop colostomy using a rectus fascial sling. This has been used successfully in fifteen patients with no complications or evidence of significant spill over of faecal contents into the efferent loop

    The impact of fire on the Late Paleozoic Earth system

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    Analyses of bulk petrographic data indicate that during the Late Paleozoic wildfires were more prevalent than at present. We propose that the development of fire systems through this interval was controlled predominantly by the elevated atmospheric oxygen concentration (p(O2)) that mass balance models predict prevailed. At higher levels of p(O2), increased fire activity would have rendered vegetation with high moisture contents more susceptible to ignition and would have facilitated continued combustion. We argue that coal petrographic data indicate that p(O2) rather than global temperatures or climate, resulted in the increased levels of wildfire activity observed during the Late Paleozoic and can therefore be used to predict it. These findings are based upon analyses of charcoal volumes in multiple coals distributed across the globe and deposited during this time period, and that were then compared with similarly diverse modern peats and Cenozoic lignites and coals. Herein, we examine the environmental and ecological factors that would have impacted fire activity and we conclude that of these factors p(O2) played the largest role in promoting fires in Late Paleozoic peat-forming environments and, by inference, ecosystems generally, when compared with their prevalence in the modern world

    UV/Optical Spectroscopy of Submillimeter Galaxies

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    We summarize the astrophysical properties of the submillimeter galaxy population gleaned from our optical and near-IR spectroscopic surveys of radio-identified SCUBA galaxies. Precise redshift information allows basic evolutionary properties to be measured, but also facilitates a large range of ancilliary science, including clustering and comparisons with the inter-galactic medium, and detection of CO molecular gas. We demonstrate that the rest-frame UV offers rich astrophysical diagnostics both from individual spectra (AGN characterization and wind outflows) and from stacked spectra of SMGs in different classes (UV-bright and faint starbursts, and type 2 AGN)

    Unravelling the Dodecahedral Spaces

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    The hyperbolic dodecahedral space of Weber and Seifert has a natural non-positively curved cubulation obtained by subdividing the dodecahedron into cubes. We show that the hyperbolic dodecahedral space has a 6-sheeted irregular cover with the property that the canonical hypersurfaces made up of the mid-cubes give a very short hierarchy. Moreover, we describe a 60-sheeted cover in which the associated cubulation is special. We also describe the natural cubulation and covers of the spherical dodecahedral space (aka Poincar\'e homology sphere).Comment: 15 pages + 6 pages appendix, 7 figures, 4 table
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