324 research outputs found

    CFD simulations of local wind fields : a parametric study

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    Establishing the local wind fields using a simulation software is an important part of the wind resource assessment. In this study the WindSim software, utilizing the Computational Fluid Dynamics (CFD) method, is used to simulate the local wind fields in an area in Southwest Norway. A total of 20 digital terrain model grids are created. Every grid has different numerical settings, with respect to the horizontal- and vertical resolution, domain buffer size and refinement area size. By comparing the vertical profiles at 29 specific turbine positions, the same positions in all 20 cases, the sensitivity of the parameters can be analysed. When performing CFD simulations of the wind fields the assumption is that a higher resolution model produces more accurate results. The main challenges of utilizing finer grids in CFD modelling today is the time consumption. The present exponential growth in computing power and the introduction of cloud computing will reduce these challenges greatly. The latter without investing in expensive local high-end computers. The sensitivity study reveals significant differences in the results with respect to the set grid parameters. The most sensitive parameter is the horizontal resolution of the grid. Higher resolution grids typically increase the variability of the results, giving higher maximum values and lower minimum values.Etablering av de lokale vindfeltene ved hjelp av en simuleringsprogramvare er en viktig del av enhver vindressursvurdering. I denne studien brukes WindSim-programvaren, som benytter numerisk fluiddynamikk metoden, for ü simulere de lokale vindfeltene i et omrüde Sørvest i Norge. Det lages totalt 20 digitale terrengmodeller. Hver modell har forskjellige numeriske innstillinger, med hensyn til horisontal- og vertikal oppløsning, størrelse pü domene buffer og avgrensningsomrüde. Ved ü sammenligne vertikale profiler for 29 spesifikke turbinposisjoner, likt for alle 20 modeller, kan sensitiviteten til parameterne analyseres. Ved simulering av vindfelt antas det at en modell med høyere oppløsning gir mer nøyaktige resultater. Hovedutfordringen ved ü bruke høyere oppløsning i numerisk fluiddynamikk i dag, er tidsforbruket. Den eksponentielle veksten i datakraft og introduksjon av sky-løsninger vil redusere disse utfordringene betraktelig. Sistnevnte uten ü investere i kostbare lokale avanserte datamaskiner. Sensitivitetsstudien avdekker betydelige forskjeller i resultatene med hensyn til de ulike numeriske innstillingene. Den mest sensitive parameteren er den horisontale oppløsningen. Modeller med høyere oppløsning øker vanligvis variasjonen i resultatene, og gir høyere maksverdier og lavere minimumsverdier.M-FORN

    Functional outcome and muscle wasting in adults with tetanus.

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    BACKGROUND: In many countries, in-hospital survival from tetanus is increasing, but long-term outcome is unknown. In high-income settings, critical illness is associated with muscle wasting and poor functional outcome, but there are few data from resource-limited settings. In this study we aimed to assess muscle wasting and long-term functional outcome in adults with tetanus. METHODS: In a prospective observational study involving 80 adults with tetanus, sequential rectus femoris ultrasound measurements were made at admission, 7 days, 14 days and hospital discharge. Functional outcome was assessed at hospital discharge using the Timed Up and Go test, Clinical Frailty Score, Barthel Index and RAND 36-item Short Form Health Survey (SF-36) and 3 and 6 months after discharge using the SF-36 and Barthel Index. RESULTS: Significant muscle wasting occurred between hospital admission and discharge (p70 y of age, functional recovery at 6 months was reduced compared with younger patients. Hospital-acquired infection and age were risk factors for muscle wasting. CONCLUSIONS: Significant muscle wasting during hospitalization occurred in patients with tetanus, the extent of which correlates with functional outcome

    'She doesn’t want to go to hospital. That’s one thing she hates’: Collective performativity in avoidable nursing home to hospital transfers

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    Older people who live with a combination of conditions experience fluctuations over time, which others may interpret as a need for medical attention. For some nursing home residents, this results in transitions in and out of hospital. Such transfers may be arranged without expectation ofimproved quality of life, can be associated with significant morbidity and mortality, and may preclude end-of-life preferences. Factors affecting avoidable hospitalisation for nursing home residents are not well understood. I aim to explore potential drivers, moving beyond deficit explanations relating to funding, training and resources. I use a framework of analysis that firstly considers medicalisation of frailty, as a state of vulnerability that provides focus for others’ action. I then draw on Judith Butler’s theory of performativity, to explore nursing homes as sites of identify work for staff, residents and families. I consider ways subjectivities can be effected through reiterative practice that is compelled by normative conventions. Trouble may arise when citational practice of healthcare staff, and performative acquiescence of residents and families, culminate in an inevitability of hospitalisation when navigating grey areas of assumed clinical risk. Principles of coproduction could present a disruptive opening, to rework power asymmetries and move toward aspirations for residents and their relatives to be at the centre of decisions about care

    Human skeletal muscle disuse atrophy: effects on muscle protein synthesis, breakdown and insulin resistance- a qualitative review

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    The ever increasing burden of an ageing population and pandemic of metabolic syndrome worldwide demands further understanding of the modifiable risk factors in reducing disability and morbidity associated with these conditions. Disuse skeletal muscle atrophy (sometimes referred to as “simple” atrophy) and insulin resistance are ‘non-pathological’ events resulting from sedentary behaviour and periods of enforced immobilization e.g. due to fractures or elective orthopaedic surgery. Yet, the processes and drivers regulating disuse atrophy and insulin resistance and the associated molecular events remain unclear – especially in humans. The aim of this review is to present current knowledge of relationships between muscle protein turnover, insulin resistance and muscle atrophy during disuse, principally in humans. Immobilisation lowers fasted state muscle protein synthesis (MPS) and induces fed-state ‘anabolic resistance’. While a lack of dynamic measurements of muscle protein breakdown (MPB) precludes defining a definitive role for MPB in disuse atrophy, some proteolytic “marker” studies (e.g. MPB genes) suggest a potential early elevation. Immobilisation also induces muscle insulin resistance (IR). Moreover, the trajectory of muscle atrophy appears to be accelerated in persistent IR states (e.g. Type II diabetes), suggesting IR may contribute to muscle disuse atrophy under these conditions. Nonetheless, the role of differences in insulin sensitivity across distinct muscle groups and its effects on rates of atrophy remains unclear. Multifaceted time-course studies into the collective role of insulin resistance and muscle protein turnover in the setting of disuse muscle atrophy, in humans, are needed to facilitate the development of appropriate countermeasures and efficacious rehabilitation protocol

    Non-invasive ventilation (NIV) as an aid to rehabilitation in acute respiratory disease

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    <p>Abstract</p> <p>Background</p> <p>Non-invasive ventilation (NIV) can increase exercise tolerance, reduce exercise induced desaturation and improve the outcome of pulmonary rehabilitation in patients with chronic respiratory disease. It is not known whether it can be applied to increase exercise capacity in patients admitted with non-hypercapnic acute exacerbations of COPD (AECOPD). We investigated the acceptability and feasibility of using NIV for this purpose.</p> <p>Methods</p> <p>On a single occasion, patients admitted with an acute exacerbation of chronic respiratory disease who were unable to cycle for five minutes at 20 watts attempted to cycle using NIV and their endurance time (T<sub>lim</sub>) was recorded. To determine feasibility of this approach in clinical practice patients admitted with AECOPD were screened for participation in a trial of regular NIV assisted rehabilitation during their hospital admission.</p> <p>Results</p> <p>In 12 patients tested on a single occasion NIV increased T<sub>lim </sub>from 184(65) seconds to 331(229) seconds (p = 0.04) and patients desaturated less (median difference = 3.5%, p = 0.029). In the second study, 60 patients were admitted to hospital during a three month period of whom only 18(30)% were eligible to participate and of these patients, only four (7%) consented to participate.</p> <p>Conclusion</p> <p>NIV improves exercise tolerance in patients with acute exacerbations of chronic respiratory disease but the applicability of this approach in routine clinical practice may be limited.</p> <p>Trial registration</p> <p><url>http://www.controlled-trials.com/ISRCTN35692743</url></p

    EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on Dietary Reference Values for protein

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    This opinion of the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) deals with the setting of Dietary Reference Values (DRVs) for protein. The Panel concludes that a Population Reference Intake (PRI) can be derived from nitrogen balance studies. Several health outcomes possibly associated with protein intake were also considered but data were found to be insufficient to establish DRVs. For healthy adults of both sexes, the average requirement (AR) is 0.66 g protein/kg body weight per day based on nitrogen balance data. Considering the 97.5th percentile of the distribution of the requirement and assuming an efficiency of utilisation of dietary protein for maintenance of 47 %, the PRI for adults of all ages was estimated to be 0.83 g protein/kg body weight per day and is applicable both to high quality protein and to protein in mixed diets. For children from six months onwards, age-dependent requirements for growth estimated from average daily rates of protein deposition and adjusted by a protein efficiency for growth of 58 % were added to the requirement for maintenance of 0.66 g/kg body weight per day. The PRI was estimated based on the average requirement plus 1.96 SD using a combined SD for growth and maintenance.For pregnancy, an intake of 1, 9 and 28 g/d in the first, second and third trimesters, respectively, is proposed in addition to the PRI for non-pregnant women. For lactation, a protein intake of 19 g/d during the first six months, and of 13 g/d after six months, is proposed in addition to the PRI for non-lactating women. Data are insufficient to establish a Tolerable Upper Intake Level (UL) for protein. Intakes up to twice the PRI are regularly consumed from mixed diets by some physically active and healthy adults in Europe and are considered safe

    Incidence of orthostatic hypotension and cardiovascular response to postoperative early mobilization in patients undergoing cardiothoracic and abdominal surgery

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    Background: In cardiothoracic and abdominal surgery, postoperative complications remain major clinical problems. Early mobilization has been widely practiced and is an important component in preventing complications, including orthostatic hypotension (OH) during postoperative management. We investigated cardiovascular response during early mobilization and the incidence of OH after cardiothoracic and abdominal surgery. Methods: In this prospective observational study, we consecutively analyzed data from 495 patients who underwent elective cardiothoracic and abdominal surgery. We examined the incidence of OH, and the independent risk factors associated with OH during early mobilization after major surgery. Multivariate logistic regression was performed using various characteristics of patients to identify OH-related independent factors. Results: OH was observed in 191 (39%) of 495 patients. The incidence of OH in cardiac, thoracic, and abdominal groups was 39 (33%) of 119, 95 (46%) of 208, and 57 (34%) of 168 patients, respectively. Male sex (OR 1.538; p = 0.03) and epidural anesthesia (OR 2.906; p < 0.001) were independently associated with OH on multivariate analysis. Conclusions: These results demonstrate that approximately 40% patients experience OH during early mobilization aftercardiothoracic and abdominal surgery. Sex was identified as an independent factor for OH during early mobilization after all three types of surgeries, while epidural anesthesia was only identified after thoracic surgery. Therefore, the frequent occurrence of OH during postoperative early mobilization should be recognized
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