384 research outputs found

    The effectiveness and variation of acute medical units: a systematic review

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    Purpose: To evaluate the evidence for the effectiveness of acute medical units (AMUs) compared with other models of care and compare the components of AMU models. Data sources: Six electronic databases and grey literature sources searched between 1990 and 2014. Study selection: Studies reporting on AMUs as an intervention for unplanned medical presentations to hospital with the inclusion of all outcome measures/study designs/comparators. Data extraction: Data on study characteristics/outcomes/AMU components were extracted by one author and confirmed by a second. Data synthesis: Seventeen studies of 12 AMUs across five countries were included. The AMU model was associated with a reduction in-hospital length of stay (LOS) in all analyses ranging from 0.3 to 2.6 days; and a reduction in mortality in 12 of the 14 analyses with the change ranging from a 0.1% increase to a 8.8% reduction. Evidence relating to readmissions and patient/staff satisfaction was less conclusive. There was variation in the following components of AMUs: admission criteria, entry sources, functions and consultant work patterns. Conclusion: This review provides evidence that AMUs are associated with reductions in-hospital LOS and, less convincingly, mortality compared with other models of care when implemented in European and Australasian settings. Reported estimates may be affected by residual confounding. This review reports heterogeneity in components of the AMU model. Further work to identify what constitutes the key components of an AMU is needed to improve the quality and effectiveness of acute medical care. This is of particular importance given the escalating demand on acute services

    A field expansions method for scattering by periodic multilayered media

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    The interaction of acoustic and electromagnetic waves with periodic structures plays an important role in a wide range of problems of scientific and technological interest. This contribution focuses upon the robust and high-order numerical simulation of a model for the interaction of pressure waves generated within the earth incident upon layers of sediment near the surface. Herein described is a boundary perturbation method for the numerical simulation of scattering returns from irregularly shaped periodic layered media. The method requires only the discretization of the layer interfaces (so that the number of unknowns is an order of magnitude smaller than finite difference and finite element simulations), while it avoids not only the need for specialized quadrature rules but also the dense linear systems characteristic of boundary integral/element methods. The approach is a generalization to multiple layers of Bruno and Reitich’s “Method of Field Expansions” for dielectric structures with two layers. By simply considering the entire structure simultaneously, rather than solving in individual layers separately, the full field can be recovered in time proportional to the number of interfaces. As with the original field expansions method, this approach is extremely efficient and spectrally accurate

    Global Phylogenomic Assessment of \u3ci\u3eLeptoseris\u3c/i\u3e and \u3ci\u3eAgaricia\u3c/i\u3e Reveals Substantial Undescibed Diversity at Mesophotic Depths

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    Background: Mesophotic coral communities are increasingly gaining attention for the unique biological diversity they host, exemplified by the numerous mesophotic fish species that continue to be discovered. In contrast, many of the photosynthetic scleractinian corals observed at mesophotic depths are assumed to be depth-generalists, with very few species characterised as mesophotic-specialists. This presumed lack of a specialised community remains largely untested, as phylogenetic studies on corals have rarely included mesophotic samples and have long suffered from resolution issues associated with traditional sequence markers. Results: Here, we used reduced-representation genome sequencing to conduct a phylogenomic assessment of the two dominant mesophotic genera of plating corals in the Indo-Pacific and Western Atlantic, respectively, Leptoseris and Agaricia. While these genome-wide phylogenies broadly corroborated the morphological taxonomy, they also exposed deep divergences within the two genera and undescribed diversity across the current taxonomic species. Five of the eight focal species consisted of at least two sympatric and genetically distinct lineages, which were consistently detected across different methods. Conclusions: The repeated observation of genetically divergent lineages associated with mesophotic depths highlights that there may be many more mesophotic-specialist coral species than currently acknowledged and that an urgent assessment of this largely unstudied biological diversity is warranted

    Differences in biological traits composition of benthic assemblages between unimpacted habitats

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    There is an implicit requirement under contemporary policy drivers to understand the characteristics of benthic communities under anthropogenically-unimpacted scenarios. We used a trait-based approach on a large dataset from across the European shelf to determine how functional characteristics of unimpacted benthic assemblages vary between different sedimentary habitats. Assemblages in deep, muddy environments unaffected by anthropogenic disturbance show increased proportions of downward conveyors and surface deposit-feeders, while burrowing, diffusive mixing, scavenging and predation traits assume greater numerical proportions in shallower habitats. Deep, coarser sediments are numerically more dominated by sessile, upward conveyors and suspension feeders. In contrast, unimpacted assemblages of coarse sediments in shallower regions are proportionally dominated by the diffusive mixers, burrowers, scavengers and predators. Finally, assemblages of gravelly sediments exhibit a relatively greater numerical dominance of non-bioturbators and asexual reproducers. These findings may be used to form the basis of ranking habitats along a functional sensitivity gradient
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