41,936 research outputs found

    The astacin metalloprotease moulting enzyme NAS-36 is required for normal cuticle ecdysis in free-living and parasitic nematodes

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    Nematodes represent one of the most abundant and species-rich groups of animals on the planet, with parasitic species causing chronic, debilitating infections in both livestock and humans worldwide. The prevalence and success of the nematodes is a direct consequence of the exceptionally protective properties of their cuticle. The synthesis of this cuticle is a complex multi-step process, which is repeated 4 times from hatchling to adult and has been investigated in detail in the free-living nematode, Caenorhabditis elegans. This process is known as moulting and involves numerous enzymes in the synthesis and degradation of the collagenous matrix. The nas-36 and nas-37 genes in C. elegans encode functionally conserved enzymes of the astacin metalloprotease family which, when mutated, result in a phenotype associated with the late-stage moulting defects, namely the inability to remove the preceding cuticle. Extensive genome searches in the gastrointestinal nematode of sheep, Haemonchus contortus, and in the filarial nematode of humans, Brugia malayi, identified NAS-36 but not NAS-37 homologues. Significantly, the nas-36 gene from B. malayi could successfully complement the moult defects associated with C. elegans nas-36, nas-37 and nas-36/nas-37 double mutants, suggesting a conserved function for NAS-36 between these diverse nematode species. This conservation between species was further indicated when the recombinant enzymes demonstrated a similar range of inhibitable metalloprotease activities

    Multimode propagation in phononic crystals with overlapping Bragg and hybridization effects

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    Unusual dispersion properties are observed in a phononic crystal of nylon rods in water when the lattice constant is adjusted so that Bragg and hybridization gaps overlap in frequency. On the basis of experimental and numerical analyses of time-dependent transmission and spatial field maps, the presence of two coexisting propagation modes of similar amplitude is demonstrated near the resonance frequency. This phenomenon is attributed to the coupling of the rod resonances arranged in a triangular lattice, with phase shifts driven by the Bragg condition.Comment: 5 pages, 5 figure

    X-ray photometry

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    I describe a method for synthesizing photometric passbands for use with current and future X-ray instruments. The method permits the standardisation of X-ray passbands and thus X-ray photometry between different instruments and missions. The method is illustrated by synthesizing a passband in the XMM-Newton EPIC pn which is similar to the ROSAT PSPC 0.5-2 keV band.Comment: Accepted for publication in MNRA

    Shock-induced separation of adiabatic turbulent boundary layers in supersonic axially symmetric internal flow

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    An experimental investigation at Mach 4 of shock-induced turbulent boundary layer separation at the walls of axially symmetric flow passages is discussed, with particular emphasis placed on determining the shock strengths required for incipient separation. The shock waves were produced by interchangeable sting-mounted cones placed on the axes of the flow passages and aligned with the freestream flow. The interactions under study simulate those encountered in axially symmetric engine inlets of supersonic aircraft. Knowledges of the shock strengths required for boundary layer separation in inlets is important since for shocks of somewhat greater strength rather drastic alterations in the inlet flow field may occur

    Evaluation of management measures of software development. Volume 1: Analysis summary

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    The conceptual model, the data classification scheme, and the analytic procedures are explained. The analytic results are summarized and specific software measures for collection and monitoring are recommended

    An exploratory study of creating dementia-friendly businesses in the visitor economy : Evidence from the UK

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    © 2019 Published by Elsevier Ltd.Many governments have promoted the development of a civil society to encourage citizen involvement in addressing many of the grand social challenges such as the growing prevalence of dementia, as ageing becomes a major trend in developed societies. One outcome has been the development of Dementia Friendly Communities, created via Dementia Action Alliances (DAAs) in England, to enhance awareness, care and the experience of people with dementia in accessing services and facilities. These initiatives are based on engaging the business community and yet no research studies have examined this theme to date. Given the growing significance of leisure and tourism activities that people with dementia and family members engage in, this study examines the experience of business engagement with DAAs in the visitor economy in England. The notion of shared value articulated by Porter and Kramer (2011) is used as a basis for understanding the type of business engagement.Peer reviewedFinal Published versio

    Living deep-water Lophelia and Madrepora corals in Maltese waters (Strait of Sicily, Mediterranean Sea)

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    The occurrence of living deep-water corals, Lophelia pertusa and Madrepora oculata, from stations 21-42 km off the southern and south-western coast of Malta is reported. Fragments of living colonies of both species, as well as some large pieces of Lophelia frameworks were recovered from depths of 390-617 m together with the solitary coral Desmophyllum dianthus (= cristagalli). The accompanying biota included the barnacle Pachylasma giganteum, the gastropod Coralliophila richardi, the bivalves Asperarca nodulosa and Spondylus gussonii, and the polychaete Eunice norvegicus, all of which are frequently associated with deep-water corals. The occurrence of the Lophelia-Madrepora- Desmophyllum triad, the large pieces of coral frameworks consisting predominantly of live, healthy polyps, and the associated biota, suggest that coral patches may be present in at least some of the investigated localities, rather than just fragmented remains or isolated colonies.peer-reviewe
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