913 research outputs found

    An assessment of principles of access for wind generation curtailment in active network management schemes

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    The growth of wind generation embedded in distribution networks is leading to the development and implementation of Active Network Management (ANM) strategies. These aim to increase the capacity of Distributed Generation (DG) that can connect to a network. One such ANM strategy is generation curtailment where DG is given a non-firm connection under which the network can instruct a generator to reduce its output under specified conditions. Currently in the UK the Orkney distribution network operates a curtailment scheme for wind and other renewable generation [1]and a similar scheme is being developed for the Shetland Islands [2]. The main objective of this paper is to explore the options for Principles of Access (PoA) for curtailment of wind generation on distribution networks which employ ANM. The PoA define the commercial rules by which a DG unit obtains access to the distribution network and under an ANM curtailment scheme the PoA defines the curtailment instructions that would be sent to different DG units when network constraints occur. The scenarios studied in this paper are based on the Orkney distribution network

    Commercial integration of storage and responsive demand to facilitate wind energy on the Shetland Islands

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    The Northern Isles New Energy Solutions (NINES) project seeks to implement Active Network Management (ANM) on the Shetland Islands in a manner which reduces customers’ energy consumption, lowers peak demand and facilitates an increase in the proportion of electricity from wind, in order to take advantage of the unique wind resource of the islands. This presentation focuses on the commercial frameworks and trading arrangements necessary to permit additional wind capacity onto the islanded network through the active use of storage and responsive demand technologies. The network is modelled using a Dynamic Optimal Power Flow (DOPF) framework, which allows the unit scheduling of different combinations of generation, storage and demand to be optimised according to different optimisation goals. This is used as a foundation to explore the value of wind energy and storage in meeting the long-term goals of the network, the forms of trading and markets which may be used to contract services, and the potential for responsive demand to facilitate different forms of connection agreements and curtailment strategies for new wind farms. In modelling the Shetland network using Dynamic Optimal Power Flow (DOPF), the optimum unit commitment schedule is determined across a daily horizon for different network topologies, including variable levels of wind generation, storage and demand-side response - primarily storage heaters and water tanks controllable by the Distribution System Operator via Active Network Management. This informs the level of wind generation which may be accepted onto the network, and allows the creation and testing of commercial agreements both for wind generators keen to utilise the unique resource of the islands, as well as allowing third-party operation of storage, and reducing the peak energy demand of domestic consumers. This allows a greater level of demand to be supplied by non-thermal sources through the time-shifting of demand against the availability of the wind resource. Support of the grid through reserve and response is considered in the context of maintaining system stability, with the aim of procuring services through third-party contractual arrangements. Data collected from the operational history of the islands and technology trials demonstrate the feasibility of these approaches and their potential applicability to other constrained distribution networks with the potential for high levels of wind generation. The data from trials of domestic storage equipment and modelling of wind curtailment demonstrate quantitatively the ways in which commercial integration of modern storage and responsive demand can be used to increase the utilisation of wind energy on islanded networks, which may often have increased renewable resources but limited grid capacity. It is shown that there are a number of trading and connection agreements which can be used to contract for generation and ancillary services to meet these goals

    Council tax valuation band predicts breast feeding and socio-economic status in the ALSPAC study population

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    BACKGROUND: Breast-feeding rates in the UK are known to vary by maternal socio-economic status but the latter function is imperfectly defined. We test if CTVB (Council Tax Valuation Band – a categorical assessment of UK property values and amenities governing local tax levies) of maternal address predicts, in a large UK regional sample of births, (a) breast-feeding (b) personal and socio-economic attributes of the mothers. METHODS: Retrospective study of a subset (n.1390 selected at random) of the ALSPAC sample (Avon Longitudinal Study of Parents and Children), a large, geographically defined cohort of mothers followed from early pregnancy to 8 weeks post-delivery. Outcome measures are attitudes to breast-feeding prior to delivery, breast-feeding intention and uptake, demographic and socio-economic attributes of the mothers, CTVB of maternal home address at the time of each birth. Logistic regression analysis, categorical tests. RESULTS: Study sample: 1360 women divided across the CTVBs – at least 155 in any band or band aggregation. CTVB predicted only one belief or attitude – that bottle-feeding was more convenient for the mother. However only 31% of 'CTVB A infants' are fully breast fed at 4 weeks of life whereas for 'CTVB E+ infants' the rate is 57%. CTVB is also strongly associated with maternal social class, home conditions, parental educational attainment, family income and smoking habit. CONCLUSION: CTVB predicts breast-feeding rates and links them with social circumstances. CTVB could be used as the basis for accurate resource allocation for community paediatric services: UK breast-feeding rates are low and merit targeted promotion

    Tile Number and Space-Efficient Knot Mosaics

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    In this paper we introduce the concept of a space-efficient knot mosaic. That is, we seek to determine how to create knot mosaics using the least number of non-blank tiles necessary to depict the knot. This least number is called the tile number of the knot. We determine strict bounds for the tile number of a knot in terms of the mosaic number of the knot. In particular, if tt is the tile number of a prime knot with mosaic number mm, then 5m−8≤t≤m2−45m-8 \leq t \leq m^2-4 if mm is even and 5m−8≤t≤m2−85m-8 \leq t \leq m^2-8 if mm is odd. We also determine the tile number of several knots and provide space-efficient knot mosaics for each of them.Comment: The original version of this article was split into two articles during refereein

    Protocol for a systematic review of screening tools for fear of recurrent illness in common life-threatening diseases

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    BackgroundA myocardial infarction (MI) (‘heart attack’) can be intensely stressful, and the impact of this event can leave patients with clinically significant post-MI stress symptoms. Untreated stress can make heart disease worse. Few tools are available that screen for specific thoughts or beliefs that can trigger post-MI stress responses. In other life-threatening illnesses, fear of recurrence (FoR) of illness has been identified as a key stressor, and screening tools have been developed to identify this. The aim of this review is to identify FoR screening tools used in other common life-threatening diseases that report on the development of the tool, to assess if there are any that can be adapted for use in MI survivors so that those with high levels of FoR can be identified and helped.Methods/DesignThe review will evaluate full FoR screening tools and methods of measurement used in common life-threatening disease clinical populations. The Campbell and Cochrane Libraries, Cumulative Index of Nursing and Allied Health Literature (CINAHL), PsycINFO, MEDLINE, Embase, Applied Social Sciences Index and Abstracts (ASSIA), Published International Literature on Traumatic Stress (PILOTS), Social Services Abstracts, Sociological Abstracts, Web of Knowledge, Health and Psychosocial Instruments and SCOPUS databases will be searched for relevant studies published from database inception. Reference lists and published reviews/meta-analyses will also be searched. All titles and abstracts will be screened and relevant full-text versions retrieved by two reviewers, who will then extract all the data. Each will independently review all data extracted by the other. Selected studies will also be assessed by two independent researchers using the COnsensus-based standards for the Selection of health status measurement INstruments (COSMIN) checklist and other quality criteria. This will be done to evaluate the degree to which their measurement properties meet the standards for good methodological quality. Disagreement will be resolved through consensus.DiscussionUntreated post-MI stress has a considerable psychological and physical impact on MI survivors. Therefore, there is a critical need to develop a screening tool to identify fear of recurrent MI so that those affected can be identified and directed to appropriate support interventions. This proposed research will enable a tool to be developed and adapted for use in the MI survivor patient population

    Post occupancy evaluation of social housing designed and built to Code for Sustainable Homes Levels 3, 4 and 5

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    In the housing sector, carbon emissions arise primarily through the consumption of energy to heat, light and ventilate our homes. Significant improvements in UK housing energy performance have been driven both by changes in legislation, and by the introduction of the Code for Sustainable Homes in 2007. Compliance with certain levels of this Code has been adopted as policy by Local and Regional Authorities, and social housing providers. The evaluation of the performance of low carbon housing requires the assessment of increasingly complex building services technology, and occupant behaviour. This added services complexity, and the expectation that tenants understand how to use it, has led to a number of unintended consequences which have resulted in a higher risk of performance failure. This study comprises the detailed evaluation of seven new social housing dwellings, designed and built to Code levels 3, 4 and 5, including comprehensive environmental monitoring, measurements of the consumption and generation of resources, and social surveys of the occupants. The results show that as the Code levels increase there is a reducing energy and water consumption rate, and an increasing energy generation rate, but only at the expense of a significantly increased risk of services system failure

    Intravenous Smart Pumps During Actual Clinical Use: A Descriptive Comparison of Primary and Secondary Infusion Practices

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    This descriptive observational study was conducted to increase understanding of medication administration practices during actual clinical use between 2 commonly used, different types of intravenous (IV) smart pumps. Compliance with manufacturer-recommended setup requirements for both primary and secondary infusions and secondary medication administration delay was compared between a head-height differential system and a cassette system. A total of 301 medication administration observations were included in this study: 102 (34%) for the linear peristaltic IV smart pump (medical–surgical: N = 51; critical care: N = 51) and 199 (66%) for the cassette pump (medical–surgical: N = 88; critical care: N = 111). Results found a 0% compliance for primary line setup and 84% compliance for secondary line setup and 1 omitted medication due to a closed clamp with the linear peristaltic system. For the cassette system, there are no head-height requirements. Two roller clamps were found to be in the closed position on initiation of the secondary infusion, but the clinician was alerted by an alarm, so no medication delays occurred. These findings support that the current system requirements for flow rate accuracy using head-height differential systems are difficult to achieve consistently at the point of care. There is a need for additional human factor designed technology to replace manual actions to improve the process of care for nurses and the safety of care for patients

    Kinetics of urinary cell cycle arrest markers for acute kidney injury following exposure to potential renal insults

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    Objectives: Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 predict the development of acute kidney injury following renal insults of varied aetiology. To aid clinical interpretation, we describe the kinetics of biomarker elevations around an exposure. Design: In an ancillary analysis of the multicenter SAPPHIRE study, we examined the kinetics of the urinary [tissue inhibitor of metalloproteinase-2]center dot[insulin-like growth factor binding protein 7] in association with exposure to common renal insults (major surgery, IV radiocontrast, vancomycin, nonsteroidal anti-inflammatory drugs, and piperacillin/tazobactam). Setting: Thirty-five sites in North America and Europe between September 2010 and June 2012. Patients: Seven hundred twenty-three critically ill adult patients admitted to the ICU. Interventions: None. Measurements and Main Results: We compared the urinary [tissue metalloproteinase-2]center dot[insulin growth factor binding protein 7] kinetics from the day prior to exposure up to 5 days after exposure in patients developing acute kidney injury stage 2-3, stage 1, or no acute kidney injury by Kidney Disease Improving Global Outcome criteria. Among the 723 patients, 679 (94%) had at least one, 70% had more than one, and 35% had three or more exposures to a known renal insult. There was a significant association between cumulative number of exposures up to study day 3 and risk of acute kidney injury (p = 0.02) but no association between the specific type of exposure and acute kidney injury (p = 0.22). With the exception of radiocontrast, patients who developed acute kidney injury stage 2-3 after one of the five exposures, had a clear rise and fall of urinary [tissue inhibitor of metalloproteinase-2]center dot[insulin-like growth factor binding protein 7] from the day of exposure to 24-48 hours later. In patients without acute kidney injury, there was no significant elevation in urinary [tissue inhibitor of metalloproteinase-2]center dot[insulin-like growth factor binding protein 7]. Conclusions: Exposure to potential renal insults is common. In patients developing acute kidney injury stage 2-3, the kinetics of urinary [tissue inhibitor of metalloproteinase-2]center dot[insulin-like growth factor binding protein 7] matched the exposure except in the case of radiocontrast

    RAMESES publication standards: realist syntheses

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    PMCID: PMC3558331This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
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