170 research outputs found

    A new stratigraphic framework for the early Neoproterozoic successions of Scotland

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    The circum-North Atlantic region archives three major late-Mesoproterozoic to Neoproterozoic tectonic episodes, the Grenville-Sveconorwegian and Renlandian orogenies followed by rifting and formation of the Iapetus Ocean, and each is bracketed by sedimentary successions that define three megasequences. In this context, we summarise sedimentological and geochronological data and propose a new stratigraphic framework for the iconic Torridonian-Moine-Dalradian successions and related units in Scotland. The Iona, Sleat, Torridon and Morar groups of the Scottish mainland and Inner Hebrides, and the Westing, Sand Voe and Yell Sound groups in Shetland, form the newly named Wester Ross Supergroup. They were deposited c. 1000–950 Ma within a foreland basin to the Grenville Orogen and, collectively, are in Megasequence 1. Some of these units record Renlandian orogenesis at c. 960-920 Ma. The newly named Loch Ness Supergroup consists of the Glenfinnan, Loch Eil and Badenoch groups of the Scottish mainland, deposited c. 900–870 Ma and are assigned to Megasequence 2. These units record Knoydartian orogenesis c. 820-725 Ma. The regionally extensive Dalradian Supergroup belongs to Megasequence 3; it was deposited c. <725-500 Ma and records the opening of the Iapetus Ocean, ultimately leading to deposition of the passive margin Cambrian-Ordovician Ardvreck and Durness groups.Publisher PDFPeer reviewe

    Caledonian and Pre-Caledonian orogenic events in Shetland, Scotland:evidence from garnet Lu-Hf and Sm-Nd geochronology

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    Garnet Lu-Hf and Sm-Nd ages from the Shetland Caledonides provide evidence of a pollorogenic history as follows: 1) c. 1050 Ma Grenvillian reworking of Neoarchaean basement; 2) c. 910 Ma Renlandian metamorphism of the Westing Group; 3) c. 622-606 Ma metamorphism of the Walls Metamorphic Series but of uncertain significance because the eastern margin of Laurentia is thought to have been in extension at that time; 4) Grampian I ophiolite obduction at c. 491 Ma followed by crustal thickening and metamorphism between c. 485 and c. 466 Ma; 5) Grampian II metamorphism between c. 458 and c. 442 Ma that appears to have been focused in areas here pre-existing foliations ere gentle-inclined and thus may have been relatively easily reworked; 6) Scandian metamorphism at c. 430 Ma, although the paucity of these ages suggests that much of Shetland did not attain temperatures for garnet growth. There is no significant difference in the timing of Caledonian orogenic events either side of the Walls Boundary Fault, although this need not preclude linkage with the Great Glen Fault. However, the incompatibility of Ediacaran events either side of the Walls Boundary Fault may indicate significant lateral displacement and requires further investigation

    Barriers and facilitators to the implementation of the advanced nurse practitioner role in primary care settings: a scoping review

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    Background: Workload and workforce issues in primary care are key drivers for the growing international trend to expand nursing roles. Advanced nurse practitioners are increasingly being appointed to take on activities and roles traditionally carried out by doctors. Successful implementation of any new role within multidisciplinary teams is complex and time-consuming, therefore it is important to understand the factors that may hinder or support implementation of the advanced nurse practitioner role in primary care settings. Objectives: To identify, appraise and synthesise the barriers and facilitators that impact implementation of advanced practitioner roles in primary care settings. Methods: A scoping review conducted using the Arksey and O’Malley (2005) framework and reported in accordance with PRISMA-ScR. Eight databases (Cochrane Library, Health Business Elite, Kings Fund Library, HMIC, Medline, CINAHL, SCOPUS and Web of Science) were searched to identify studies published in English between 2002 and 2017. Study selection and methodological assessment were conducted by two independent reviewers. A pre-piloted extraction form was used to extract the following data: study characteristics, context, participants and information describing the advanced nurse practitioner role. Deductive coding for barriers and facilitators was undertaken using a modified Yorkshire Contributory Framework. We used inductive coding for barriers or facilitators that could not be classified using pre-defined codes. Disagreements were addressed through discussion. Descriptive data was tabulated within evidence tables, and key findings for barriers and facilitators were brought together within a narrative synthesis based on the volume of evidence. Findings: Systematic searching identified 5976 potential records, 2852 abstracts were screened, and 122 full texts were retrieved. Fifty-four studies (reported across 76 publications) met the selection criteria. Half of the studies (n=27) were conducted in North America (n=27), and 25/54 employed a qualitative design. The advanced nurse practitioner role was diverse, working across the lifespan and with different patient groups. However, there was little agreement about the level of autonomy, or what constituted everyday activities. Team factors were the most frequently reported barrier and facilitator. Individual factors, lines of responsibility and ‘other’ factors (i.e. funding), were also frequently reported barriers. Facilitators included individual factors, supervision and leadership and ‘other’ factors (i.e. funding, planning for role integration). Conclusion: Building collaborative relationships with other healthcare professionals and negotiating the role are critical to the success of the implementation of the advanced nurse practitioner role. Team consensus about the role and how it integrates into the wider team is also essential

    Identification of mantle peridotite as a possible Iapetan ophiolite sliver in south Shetland, Scottish Caledonides

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    The Neoproterozoic Dunrossness Spilite Subgroup of south Shetland, Scotland, has been interpreted as a series of komatiitic and mafic lava flows formed in a marginal basin in response to Laurentian continental margin rifting. We show that ultramafic rocks previously identified as komatiites are depleted mantle peridotites that experienced seafloor hydrothermal alteration. The presence of positive Bouguer gravity and aeromagnetic anomalies extending from the Dunrossness Spilite Subgroup northward to the Shetland Ophiolite Complex suggests instead that these rocks may form part of an extensive ophiolite sliver, obducted during Iapetus Ocean closure in a forearc setting

    Deploying building simulation to enhance the experimental design of a full-scale empirical validation project

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    Empirical validation of building simulation results is a complex and time-consuming process. A well-structured and thorough experimental design is therefore a crucial step of the experimental procedure. A full-scale empirical validation study is planned to take place within IEA EBC Annex 71: “Building energy performance assessment based on in situ measurements”. The experimental data are currently being gathered in two experiments being conducted at the Fraunhofer IBP test site at Holzkirchen in Germany. This paper describes the methodology followed during the experimental design of the project. Particular focus is on how Building Performance Simulation (BPS) was used to assist the preparation of the actual experiment, to determine suitable test sequences, magnitudes of heat inputs and temperature variations. A combination of both deterministic and probabilistic simulation (using the method of Morris) is employed to replicate the actual experiment and to assess the sensitivity of the model to uncertain input parameters. A number of experimental errors are identified in the experiment, primarily concerning the magnitude of heat inputs. Moreover, the paper includes a discussion on lessons learned from the simulations and on the reliability, reproducibility and limitations of the suggested experimental design procedure

    Dampness and moulds in relation to respiratory and allergic symptoms in children : results from phase two of the International Study of Asthma and Allergies in Childhood, (ISAAC Phase Two)

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    Many studies report that damp housing conditions are associated with respiratory symptoms. Less is known about mechanisms and possible effect modifiers. Studies of dampness in relation to allergic sensitization and eczema are scarce. Objective We study the influence of damp housing conditions world-wide on symptoms and objective outcomes. Cross-sectional studies of 8–12-year-old children in 20 countries used standardized methodology from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge (n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled and analysed for house dust mite (HDM) allergens and endotoxin. Current exposure to dampness was more common for wheezy children (pooled odds ratio 1.58, 95% CI 1.40–1.79) and was associated with greater symptom severity among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in damp homes (OR 1.16, 1.03–1.32). HDM-allergen levels were higher in damp homes and were positively associated with HDM-sensitization, but not wheeze. A consistent association of dampness with respiratory and other symptoms was found in both affluent and non-affluent countries, among both atopic and non-atopic children. HDM exposure and sensitization may contribute, but the link seems to be related principally to non-atopic mechanisms.peer-reviewe
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