65 research outputs found

    The 1979-2005 Greenland ice sheet melt extent from passive microwave data using an improved version of the melt retrieval XPGR algorithm

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    Analysis of passive microwave satellite observations over the Greenland ice sheet reveals a significant increase in surface melt over the period 1979-2005. Since 1979, the total melt area was found to have increased +1.22 x 10ˆ7 kmˆ2. An improved version of the cross-polarized gradient ratio (XPGR) technique is used to identify the melt from the brightness temperatures. The improvements in the melt retrieval XPGR algorithm as well as the surface melt acceleration are discussed with results from a coupled atmosphere-snow regional climate model. From 1979 to 2005, the ablation period increases everywhere over the melt zone except in the regions where the model simulates an increased summer snowfall. Indeed, more snowfall in summer decreases the liquid water content of the snowpack, raises the albedo and therefore reduces the melt. Finally, this melt acceleration over the Greenland ice sheet is highly correlated with both Greenland and global warming suggesting a continuing surface melt increase in the future.Peer reviewe

    Photon Exchange in Nucleus-Nucleus Collisions

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    The strong electromagnetic fields in peripheral heavy ion collisions give rise to photon-photon and photon-nucleus interactions. I present a general survey of the photon-photon and photon-hadron physics accessible in these collisions. Among these processes I discuss the nuclear fragmentation through the excitation of giant resonances, the Coulomb dissociation method for application in nuclear astrophysics, and the production of particles.Comment: 51 pages, 16 figure

    Evaluation of a high-resolution regional climate simulation over Greenland

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    A simulation of the 1991 summer has been performed over south Greenland with a coupled atmosphere–snow regional climate model (RCM) forced by the ECMWF re-analysis. The simulation is evaluated with in-situ coastal and ice-sheet atmospheric and glaciological observations. Modelled air temperature, specific humidity, wind speed and radiative fluxes are in good agreement with the available observations, although uncertainties in the radiative transfer scheme need further investigation to improve the model’s performance. In the sub-surface snow-ice model, surface albedo is calculated from the simulated snow grain shape and size, snow depth, meltwater accumulation, cloudiness and ice albedo. The use of snow metamorphism processes allows a realistic modelling of the temporal variations in the surface albedo during both melting periods and accumulation events. Concerning the surface albedo, the main finding is that an accurate albedo simulation during the melting season strongly depends on a proper initialization of the surface conditions which mainly result from winter accumulation processes. Furthermore, in a sensitivity experiment with a constant 0.8 albedo over the whole ice sheet, the average amount of melt decreased by more than 60%, which highlights the importance of a correctly simulated surface albedo. The use of this coupled atmosphere–snow RCM offers new perspectives in the study of the Greenland surface mass balance due to the represented feedback between the surface climate and the surface albedo, which is the most sensitive parameter in energy-balance-based ablation calculations.Peer reviewe

    ‘Not a country at all’: landscape and Wuthering Heights

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    This article explores the issue of women’s representational genealogies through an analysis of Andrea Arnold’s 2011 Wuthering Heights. Beginning with 1970s feminist arguments for a specifically female literary tradition, it argues that running through both these early attempts to construct an alternative female literary tradition and later work in feminist philosophy, cultural geography and film history is a concern with questions of ‘alternative landscapes’: of how to represent, and how to encounter, space differently. Adopting Mary Jacobus’ notion of intertextual ‘correspondence’ between women’s texts, and taking Arnold’s film as its case study, it seeks to trace some of the intertextual movements – the reframings, deframings and spatial reorderings – that link Andrea Arnold’s film to Emily Brontë’s original novel. Focusing on two elements of her treatment of landscape – her use of ‘unframed’ landscape and her focus on visceral textural detail – it points to correspondences in other women’s writing, photography and film-making. It argues that these intensely tactile close-up sequences which puncture an apparently realist narrative constitute an insistent presence beneath, or within, the ordered framing which is our more usual mode of viewing landscape. As the novel Wuthering Heights is unmade in Arnold’s adaptation and its framings ruptured, it is through this disturbance of hierarchies of time, space and landscape that we can trace the correspondences of an alternative genealogy

    Pain in elderly people with severe dementia: A systematic review of behavioural pain assessment tools

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    BACKGROUND: Pain is a common and major problem among nursing home residents. The prevalence of pain in elderly nursing home people is 40–80%, showing that they are at great risk of experiencing pain. Since assessment of pain is an important step towards the treatment of pain, there is a need for manageable, valid and reliable tools to assess pain in elderly people with dementia. METHODS: This systematic review identifies pain assessment scales for elderly people with severe dementia and evaluates the psychometric properties and clinical utility of these instruments. Relevant publications in English, German, French or Dutch, from 1988 to 2005, were identified by means of an extensive search strategy in Medline, Psychinfo and CINAHL, supplemented by screening citations and references. Quality judgement criteria were formulated and used to evaluate the psychometric aspects of the scales. RESULTS: Twenty-nine publications reporting on behavioural pain assessment instruments were selected for this review. Twelve observational pain assessment scales (DOLOPLUS2; ECPA; ECS; Observational Pain Behavior Tool; CNPI; PACSLAC; PAINAD; PADE; RaPID; Abbey Pain Scale; NOPPAIN; Pain assessment scale for use with cognitively impaired adults) were identified. Findings indicate that most observational scales are under development and show moderate psychometric qualities. CONCLUSION: Based on the psychometric qualities and criteria regarding sensitivity and clinical utility, we conclude that PACSLAC and DOLOPLUS2 are the most appropriate scales currently available. Further research should focus on improving these scales by further testing their validity, reliability and clinical utility

    A mixed methods pilot study with a cluster randomized control trial to evaluate the impact of a leadership intervention on guideline implementation in home care nursing

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    Abstract Background Foot ulcers are a significant problem for people with diabetes. Comprehensive assessments of risk factors associated with diabetic foot ulcer are recommended in clinical guidelines to decrease complications such as prolonged healing, gangrene and amputations, and to promote effective management. However, the translation of clinical guidelines into nursing practice remains fragmented and inconsistent, and a recent homecare chart audit showed less than half the recommended risk factors for diabetic foot ulcers were assessed, and peripheral neuropathy (the most significant predictor of complications) was not assessed at all. Strong leadership is consistently described as significant to successfully transfer guidelines into practice. Limited research exists however regarding which leadership behaviours facilitate and support implementation in nursing. The purpose of this pilot study is to evaluate the impact of a leadership intervention in community nursing on implementing recommendations from a clinical guideline on the nursing assessment and management of diabetic foot ulcers. Methods Two phase mixed methods design is proposed (ISRCTN 12345678). Phase I: Descriptive qualitative to understand barriers to implementing the guideline recommendations, and to inform the intervention. Phase II: Matched pair cluster randomized controlled trial (n = 4 centers) will evaluate differences in outcomes between two implementation strategies. Primary outcome: Nursing assessments of client risk factors, a composite score of 8 items based on Diabetes/Foot Ulcer guideline recommendations. Intervention: In addition to the organization's 'usual' implementation strategy, a 12 week leadership strategy will be offered to managerial and clinical leaders consisting of: a) printed materials, b) one day interactive workshop to develop a leadership action plan tailored to barriers to support implementation; c) three post-workshop teleconferences. Discussion This study will provide vital information on which leadership strategies are well received to facilitate and support guideline implementation. The anticipated outcomes will provide information to assist with effective management of foot ulcers for people with diabetes. By tracking clinical outcomes associated with guideline implementation, health care administrators will be better informed to influence organizational and policy decision-making to support evidence-based quality care. Findings will be useful to inform the design of future multi-centered trials on various clinical topics to enhance knowledge translation for positive outcomes. Trial Registration Current Control Trials ISRCTN0691089

    Improvement to numerical predictions of aerodynamic flows using experimental data assimilation

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    Improvement to Numerical Predictions of Aerodynamic Flows Using Experimental Data Assimilation

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    Modelling of snow and ice melt at ETH Camp (West Greenland): A study of surface albedo

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    [1] The objective of this paper is to present the validation over Greenland of a thermodynamic snow-ice model that was complemented with the snow metamorphism and albedo parameterizations of the Centre d'Etudes de la Neige (Grenoble, France) in order to make the surface albedo variable and interactive. Special attention is given to the surface albedo since it is the most important parameter in energy exchanges with the atmosphere for snow and ice melt. The development of an integrated (snow, ice, and water) albedo model takes into account the different surface types observed on an ice sheet, and the snow albedo is calculated from the simulated surface snow grains. The validation for a polar site has been done at ETH Camp (West Greenland, 1155 m above sea level) during the 1990 and 1991 summer seasons. Although both ablation seasons differed greatly (in 1990 it showed a negative mass balance while in 1991 it ended with a positive mass balance), a single model configuration was able to provide good results for both 1990 and 1991. These simulations show that the snow metamorphism laws included enable an accurate simulation of the surface albedo and henceforth of the surface mass balance for a polar site, provided that the snow model is correctly forced at its surface level and that meltwater retention, percolation, and drainage are well represented in the snow model. The model results are also compared with two other modeling approaches, and differences between the three snow models are detailed
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