45 research outputs found

    Performance assessment of a tidal turbine using two flow references

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    The measurement of power performance is an important procedure in the design verification and ongoing health monitoring of a tidal turbine. Standardised methods state that the performance should be measured relative to two independently located flow sensors, the arrangement of which is often non-trivial and necessitates additional cost. Recent interest in the usage of flow sensors mounted on the turbine has demonstrated their capabilities in profiling the rotor approach flow, but this instrument configuration is not recognised in the performance assessment standard. This study evaluates the merits of the turbine mounted configuration by measuring the performance of a tidal turbine relative to this reference and to a conventional seabed placed instrument. The turbine mounted sensor is found to provide a better reference of the free-stream conditions, evident from an improved agreement with theoretical predictions of device performance and a reduced amount of variation in the results. This new method could reduce both the costs and uncertainty associated with existing performance assessment best practices

    Poor Pre-Operative Emotional Health Limits Gain in Function after Total Hip Replacement

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    Introduction: While total joint replacement surgery successfully reduce joint pain and is associated with a low complication rate, patients experience a wide variation in functional improvement. Pre-surgery emotional state correlates with post-surgical functional improvement in total knee replacement patients. We tested this concept against a national cohort of total hip replacement (THR) patients. Materials & methods: Patients undergoing primary THR from 7/1/11 through 12/6/13 with postoperative outcomes at 6 months were identified from FORCE-TJR, a US national research consortium. We obtained data on patient demographics, underlying type of arthritis, body mass index (BMI), Charlson Comorbidity Index, arthritic pain in contralateral hip and bilateral knees, back pain, Hip Disability and Osteoarthritis Outcome Score (HOOS), global function based on the Short Form 36 (SF-36) Physical Component Score (PCS) and emotional health using the SF-36 Mental Component Score (MCS). We performed descriptive statistics and multivariable linear regression models to identify factors associated with 6-month postoperative PCS global function scores. Results: The 1,426 THR patients identified were 60.7% female, 95.0% white, mean age 65.3 years, mean BMI of 29.0. Mean preoperative surgical joint pain, stiffness and function was 50.1 (± 19.2), 38.7 (± 21.9), 46.4 (±19.2) respectively. MCS was 51.56 (± 12.2) and PCS 31.6 (± 8.9). Pre-operative and post-operative functioning differed based on emotional health (MCS ≥50). In multivariable models, lower MCS levels were associated with worse PCS at 6 months (coefficient of 0.18. 95% CI 0.14-0.22) after controlling for demographics, medical comorbidity, baseline PCS and burden of musculoskeletal disease. Conclusion: Poorer emotional health is associated with poorer global function following surgery and a key factor in the recovery and rehabilitation following THR. Better emotional health screening for THR surgical candidates, and interventions to provide additional emotional support to those who need it, are necessary to ensure optimal functional gain

    The rheumatoid arthritis treat-to-target trial: a cluster randomized trial within the Corrona rheumatology network

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    BACKGROUND: The treat-to-target (T2T) approach to the care of patients with rheumatoid arthritis involves using validated metrics to measure disease activity, frequent follow-up visits for patients with moderate to high disease activity, and escalation of therapy when patients have inadequate therapeutic response as assessed by standard disease activity scores. The study described is a newly launched cluster-randomized behavioral intervention to assess the feasibility and effectiveness of the T2T approach in US rheumatology practices. It is designed to identify patient and provider barriers to implementing T2T management. This initial paper focuses on the novel study design and methods created to provide these insights. METHODS/DESIGN: This trial cluster-randomizes rheumatology practices from the existing Corrona network of private and academic sites rather than patients within sites or individual investigators to provide either T2T or usual care (UC) for qualified patients who meet the 2010 revised American College of Rheumatology criteria for the diagnosis of rheumatoid arthritis and have moderate to high disease activity. Specific medication choices are left to the investigator and patient, rather than being specified in the protocol. Enrollment is expected to be completed by the end of 2013, with 30 practices randomized and enrolling a minimum of 530 patients. During the 12-month follow-up, visits are mandated as frequently as monthly in patients with active disease in the T2T group and every 3 months for the UC group. Safety data are collected at each visit. The coprimary endpoints include a comparison of the proportion of patients achieving low disease activity in the T2T and UC groups and assessment of the feasibility of implementing T2T in rheumatology practices, specifically assessment of the rates of treatment acceleration, frequency of visits, time to next visit conditional on disease activity, and probability of acceleration conditional on disease activity in the 2 groups. DISCUSSION: This cluster-randomized behavioral intervention study will provide valuable insights on the outcomes and feasibility of employing a T2T treatment approach in clinical practice in the United States. TRIAL REGISTRATION: NCT01407419

    Cluster-Randomized Trial of a Behavioral Intervention to Incorporate a Treat-to-Target Approach to Care of US Patients With Rheumatoid Arthritis

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    OBJECTIVE: To assess the feasibility and efficacy of implementing a treat-to-target approach versus usual care in a US-based cohort of rheumatoid arthritis patients. METHODS: In this behavioral intervention trial, rheumatology practices were cluster-randomized to provide treat-to-target care or usual care. Eligible patients with moderate/high disease activity (Clinical Disease Activity Index [CDAI] score \u3e 10) were followed for 12 months. Both treat-to-target and usual care patients were seen every 3 months. Treat-to-target providers were to have monthly visits with treatment acceleration at a minimum of every 3 months in patients with CDAI score \u3e 10; additional visits and treatment acceleration were at the discretion of usual care providers and patients. Coprimary end points were feasibility, assessed by rate of treatment acceleration conditional on CDAI score \u3e 10, and achievement of low disease activity (LDA; CDAI score \u3c /=10) by an intent-to-treat analysis. RESULTS: A total of 14 practice sites per study arm were included (246 patients receiving treat-to-target and 286 receiving usual care). The groups had similar baseline demographic and clinical characteristics. Rates of treatment acceleration (treat-to-target 47% versus usual care 50%; odds ratio [OR] 0.92 [95% confidence interval (95% CI) 0.64, 1.34]) and achievement of LDA (treat-to-target 57% versus usual care 55%; OR 1.05 [95% CI 0.60, 1.84]) were similar between groups. Treat-to-target providers reported patient reluctance and medication lag time as common barriers to treatment acceleration. CONCLUSION: This study is the first to examine the feasibility and efficacy of a treat-to-target approach in typical US rheumatology practice. Treat-to-target care was not associated with increased likelihood of treatment acceleration or achievement of LDA, and barriers to treatment acceleration were identified

    The Genomes of the Fungal Plant Pathogens Cladosporium fulvum and Dothistroma septosporum Reveal Adaptation to Different Hosts and Lifestyles But Also Signatures of Common Ancestry.

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    We sequenced and compared the genomes of the Dothideomycete fungal plant pathogensCladosporium fulvum (Cfu) (syn. Passalora fulva) and Dothistroma septosporum (Dse) that are closely related phylogenetically, but have different lifestyles and hosts. Although both fungi grow extracellularly in close contact with host mesophyll cells, Cfu is a biotroph infecting tomato, while Dse is a hemibiotroph infecting pine. The genomes of these fungi have a similar set of genes (70% of gene content in both genomes are homologs), but differ significantly in size (Cfu \u3e61.1-Mb; Dse 31.2-Mb), which is mainly due to the difference in repeat content (47.2% in Cfu versus 3.2% in Dse). Recent adaptation to different lifestyles and hosts is suggested by diverged sets of genes. Cfu contains an α-tomatinase gene that we predict might be required for detoxification of tomatine, while this gene is absent in Dse. Many genes encoding secreted proteins are unique to each species and the repeat-rich areas in Cfu are enriched for these species-specific genes. In contrast, conserved genes suggest common host ancestry. Homologs of Cfu effector genes, including Ecp2 and Avr4, are present in Dse and induce a Cf-Ecp2- and Cf-4-mediated hypersensitive response, respectively. Strikingly, genes involved in production of the toxin dothistromin, a likely virulence factor for Dse, are conserved in Cfu, but their expression differs markedly with essentially no expression by Cfu in planta. Likewise, Cfu has a carbohydrate-degrading enzyme catalog that is more similar to that of necrotrophs or hemibiotrophs and a larger pectinolytic gene arsenal than Dse, but many of these genes are not expressed in planta or are pseudogenized. Overall, comparison of their genomes suggests that these closely related plant pathogens had a common ancestral host but since adapted to different hosts and lifestyles by a combination of differentiated gene content, pseudogenization, and gene regulation

    Intelligent relaying A multi-hop extension to personal communication systems

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    SIGLEAvailable from British Library Document Supply Centre- DSC:DXN062710 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

    Applying Climate Changes Simulated by GCMs to the Generation of Fine-Scale Rainfall Scenarios

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    The impact of the mode of survey administration on estimates of daily smoking for mobile phone only users

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    Background: Over the past decade, there have been substantial changes in landline and mobile phone ownership, with a substantial increase in the proportion of mobile-only households. Estimates of daily smoking rates for the mobile phone only (MPO) population have been found to be substantially higher than the rest of the population and telephone surveys that use a dual sampling frame (landline and mobile phones) are now considered best practice. Smoking is seen as an undesirable behaviour; measuring such behaviours using an interviewer may lead to lower estimates when using telephone based surveys compared to self-administered approaches. This study aims to assess whether higher daily smoking estimates observed for the mobile phone only population can be explained by administrative features of surveys, after accounting for differences in the phone ownership population groups. Methods: Data on New South Wales (NSW) residents aged 18 years or older from the NSW Population Health Survey (PHS), a telephone survey, and the National Drug Strategy Household Survey (NDSHS), a self-administered survey, were combined, with weights adjusted to match the 2013 population. Design-adjusted prevalence estimates and odds ratios were calculated using survey analysis procedures available in SAS 9.4. Results: Both the PHS and NDSHS gave the same estimates for daily smoking (12%) and similar estimates for MPO users (20% and 18% respectively). Pooled data showed that daily smoking was 19% for MPO users, compared to 10% for dual phone owners, and 12% for landline phone only users. Prevalence estimates for MPO users across both surveys were consistently higher than other phone ownership groups. Differences in estimates for the MPO population compared to other phone ownership groups persisted even after adjustment for the mode of collection and demographic factors. Conclusions: Daily smoking rates were consistently higher for the mobile phone only population and this was not driven by the mode of survey collection. This supports the assertion that the use of a dual sampling frame addresses coverage issues that would otherwise be present in telephone surveys that only made use of a landline sampling frame

    Stochastic generation of daily rainfall for catchment water management studies

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    This thesis presents an approach for generating long synthetic sequences of single-site daily rainfall which can incorporate low-frequency features such as drought, while still accurately representing the day-to-day variations in rainfall. The approach is implemented in a two-stage process. The first stage is to generate the entire sequence of rainfall occurrence (i.e. whether each day is dry or wet). The second stage is to generate the rainfall amount on all wet days in the sequence. The models used in both stages are nonparametric (they make minimal general assumptions rather than specific assumptions about the distributional and dependence characteristics of the variables involved), and ensure an appropriate representation of the seasonal variations in rainfall. A key aspect in formulation of the models is selection of the predictor variables used to represent the historical features of the rainfall record. Methods for selection of the predictors are presented here. The approach is applied to daily rainfall from Sydney and Melbourne. The models that are developed use daily-level, seasonal-level, annual-level, and multi-year predictors for rainfall occurrence, and daily-level and annual-level predictors for rainfall amount. The resulting generated sequences provide a better representation of the variability associated with droughts and sustained wet periods than was previously possible. These sequences will be useful in catchment water management studies as a tool for exploring the potential response of catchments to possible future rainfall

    Objectively Measured Physical Activity and Symptoms Change in Knee Osteoarthritis

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    OBJECTIVE: The study objective was to quantify the association between daily physical activity measured by accelerometer and 1-year changes in symptoms among people with knee osteoarthritis. METHODS: Participants from the Osteoarthritis Initiative had knee radiographs and physical activity assessed using GT1M ActiGraph (Pensacola, FL) uniaxial accelerometers at the 48-month visit. Physical activity was calculated and categorized as tertiles of average daily minutes in light and moderate-to-vigorous activity. Outcomes were 1-year change in symptoms measured by Western Ontario and McMaster Universities scales, including pain, stiffness, and physical function. Adjusted multivariable linear models estimated the relationship between tertiles of light or moderate-to-vigorous physical activity and changes in knee symptoms. RESULTS: Among 1059 participants (55% were women; mean age, 66 +/- 9 years), greater time in light activity was associated with a trend toward declined physical function (P = .01). Greater time in daily moderate-to-vigorous activity also was associated with declined physical function (P = .01) and increased pain (P = .08). None of these average changes in symptoms reached minimally important clinical differences. However, greater daily time in both activities was associated with a higher probability of worsening symptoms among persons with Kellgren-Lawrence grade 4 osteoarthritis. CONCLUSIONS: Objectively measured daily activity was not associated with 1-year symptom improvements among community-dwelling adults with knee osteoarthritis. In those with advanced disease (Kellgren-Lawrence grade 4), greater daily minutes in physical activity were associated with worsening symptoms. How best to implement exercise regimens in persons with advanced knee osteoarthritis to reduce the deleterious impact on symptoms needs to be explored
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