257 research outputs found

    Effects of Wood Properties and Chipping Length on the Operational Efficiency of a 30 kW Electric Disc Chipper

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    The development of efficient woody biomass comminuting processes and systems is of great importance for establishing bio-refineries. Using hybrid systems, which store excess energy from a diesel engine during periods of low loading for use during peak loading times, may yield higher energy efficiency compared to direct diesel-powered comminuting systems. In order to design hybrid chippers, a series of data are required on the load variations, in order to estimate the amount of energy that needs to be stored, and the peak power required. As a consequence, a detailed knowledge of the effects of wood properties on the direct power consumption during chipping is relevant. Therefore, the objectives of this work were to study the effects of wood properties (size and density) of pine, spruce and birch trees from early thinnings in the north of Sweden on the specific power and energy demand and time consumption of a 30 kW electric chipper while producing chips of two sizes. The study has generated models that replicate the processes, which can be used when designing efficient hybrid systems. The butt area had a significant effect on the power requirements when chipping and, along with chip length, had a significant effect on the energy requirements. Butt area and chip length also had a significant effect on the chipping productivity. There were small effects caused by the OD densities and by different species. These findings agree with previous studies and can be used for designing future hybrid chippers

    Analyzing repeated data collected by mobile phones and frequent text messages. An example of Low back pain measured weekly for 18 weeks

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    BACKGROUND: Repeated data collection is desirable when monitoring fluctuating conditions. Mobile phones can be used to gather such data from large groups of respondents by sending and receiving frequently repeated short questions and answers as text messages. The analysis of repeated data involves some challenges. Vital issues to consider are the within-subject correlation, the between measurement occasion correlation and the presence of missing values. The overall aim of this commentary is to describe different methods of analyzing repeated data. It is meant to give an overview for the clinical researcher in order for complex outcome measures to be interpreted in a clinically meaningful way. METHODS: A model data set was formed using data from two clinical studies, where patients with low back pain were followed with weekly text messages for 18 weeks. Different research questions and analytic approaches were illustrated and discussed, as well as the handling of missing data. In the applications the weekly outcome “number of days with pain” was analyzed in relation to the patients’ “previous duration of pain” (categorized as more or less than 30 days in the previous year). Research questions with appropriate analytical methods 1: How many days with pain do patients experience? This question was answered with data summaries. 2: What is the proportion of participants “recovered” at a specific time point? This question was answered using logistic regression analysis. 3: What is the time to recovery? This question was answered using survival analysis, illustrated in Kaplan-Meier curves, Proportional Hazard regression analyses and spline regression analyses. 4: How is the repeatedly measured data associated with baseline (predictor) variables? This question was answered using generalized Estimating Equations, Poisson regression and Mixed linear models analyses. 5: Are there subgroups of patients with similar courses of pain within the studied population? A visual approach and hierarchical cluster analyses revealed different subgroups using subsets of the model data. CONCLUSIONS: We have illustrated several ways of analysing repeated measures with both traditional analytic approaches using standard statistical packages, as well as recently developed statistical methods that will utilize all the vital features inherent in the data

    Experiences of participating in a problem-solving intervention with workplace involvement in Swedish primary health care:a qualitative study from rehabilitation coordinator's, employee's, and manager's perspectives

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    BACKGROUND: Work-directed interventions that include problem-solving can reduce the number of sickness absence days. The effect of combining a problem-solving intervention with involvement of the employer is currently being tested in primary care in Sweden for employees on sickness absence due to common mental disorders (PROSA trial). The current study is part of the PROSA trial and has a two-fold aim: 1) to explore the experiences of participating in a problem-solving intervention with workplace involvement aimed at reducing sickness absence in employees with common mental disorders, delivered in Swedish primary health care, and 2) to identify facilitators of and barriers to participate in the intervention. Both aims targeted rehabilitation coordinators, employees on sickness absence, and first-line managers.METHODS: Data were collected from semi-structured interviews with participants from the PROSA intervention group; rehabilitation coordinators (n = 8), employees (n = 13), and first-line managers (n = 8). Content analysis was used to analyse the data and the Consolidated Framework for Implementation Research was used to group the data according to four contextual domains. One theme describing the participation experiences was established for each domain. Facilitators and barriers for each domain and stakeholder group were identified.RESULTS: The stakeholders experienced the intervention as supportive in identifying problems and solutions and enabling a dialogue between them. However, the intervention was considered demanding and good relationships between the stakeholders were needed. Facilitating factors were the manual and work sheets which the coordinators were provided with, and the manager being involved early in the return-to-work process. Barriers were the number of on-site meetings, disagreements and conflicts between employees and first-line managers, and symptom severity.CONCLUSIONS: Seeing the workplace as an integral part of the intervention by always conducting a three-part meeting enabled a dialogue that can be used to identify and address disagreements, to explain CMD symptoms, and how these can be handled at the workplace. We suggest allocating time towards developing good relationships, provide RCs with training in handling disagreements, and additional knowledge about factors in the employee's psychosocial work environment that can impair or promote health to increase the RCs ability to support the employee and manager.</p

    Autoradiographic Mapping of 5-HT1B/1D Binding Sites in the Rhesus Monkey Brain Using [carbonyl-11C]zolmitriptan

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    Zolmitriptan is a serotonin 5-HT1B/1D receptor agonist that is an effective and well-tolerated drug for migraine treatment. In a human positron emission tomography study, [11C]zolmitriptan crossed the blood-brain barrier but no clear pattern of regional uptake was discernable. The objective of this study was to map the binding of [11C]zolmitriptan in Rhesus monkey brain using whole hemisphere in vitro autoradiography with [11C]zolmitriptan as a radioligand. In saturation studies, [11C]zolmitriptan showed specific (90%) binding to a population of high-affinity binding sites (Kd 0.95–5.06 nM). There was regional distribution of binding sites with the highest density in the ventral pallidum, followed by the external globus pallidus, substantia nigra, visual cortex, and nucleus accumbens. In competitive binding studies with 5-HT1 receptor antagonists, [11C]zolmitriptan binding was blocked by selective 5-HT1B and 5-HT1D ligands in all target areas. There was no appreciable change in binding with the addition of a 5-HT1A receptor antagonist

    AGR2, an Endoplasmic Reticulum Protein, Is Secreted into the Gastrointestinal Mucus

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    The MUC2 mucin is the major constituent of the two mucus layers in colon. Mice lacking the disulfide isomerase-like protein Agr2 have been shown to be more susceptible to colon inflammation. The Agr2(-/-) mice have less filled goblet cells and were now shown to have a poorly developed inner colon mucus layer. We could not show AGR2 covalently bound to recombinant MUC2 N- and C-termini as have previously been suggested. We found relatively high concentrations of Agr2 in secreted mucus throughout the murine gastrointestinal tract, suggesting that Agr2 may play extracellular roles. In tissue culture (CHO-K1) cells, AGR2 is normally not secreted. Replacement of the single Cys in AGR2 with Ser (C81S) allowed secretion, suggesting that modification of this Cys might provide a mechanism for circumventing the KTEL endoplasmic reticulum retention signal. In conclusion, these results suggest that AGR2 has both intracellular and extracellular effects in the intestine

    Development and comorbidity of eczema, asthma and rhinitis to age 12 : data from the BAMSE birth cohort

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    BACKGROUND: Allergy-related diseases are a public health issue, but knowledge on development and comorbidity among children is scarce. The aim was to study the development of eczema, asthma and rhinitis in relation to sex and parental allergy, in a population-based cohort, during childhood. METHODS: At 1, 2, 4, 8 and 12 years, parental questionnaires were used to obtain data on allergy-related diseases. Complete data for all five follow-up occasions were available from 2916 children. Odds ratios for the risk of any allergy-related disease in relation to heredity and sex were calculated using generalized estimating equations. RESULTS: At 12 years, 58% of the children had had eczema, asthma and/or rhinitis at some time. Disease turnover was high for all three diseases throughout the study. Comorbidity increased with age, and at 12 years, 7.5% of all the children were affected by at least two allergy-related diseases. Parental allergy was associated with increased comorbidity and more persistent disease and increased the risk of having any allergy-related disease (adjusted OR 1.76; 95% CI 1.57-1.97) up to 12 years. Male sex was associated with an increased risk throughout childhood. Boys and girls did not differ in disease persistence, and for comorbidity, the differences were minor. CONCLUSIONS: Allergy-related diseases may affect a majority of children. Eczema, asthma and rhinitis develop dynamically throughout childhood, and allergic comorbidity is common. These findings indicate that allergy-related diseases should be neither seen nor studied as isolated entities.Stockholm County CouncilHjÀrt- och LungfondenVetenskapsrÄdetAstma- och allergiförbundetManuscrip

    Genetisk undersökning av torsk frĂ„n Ålands hav

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    För att undersöka om torsken i Ålands hav kan utgöra ett separat lekbestĂ„nd har Sveriges lantbruksuniversitet och Göteborgs universitet gjort genetiska slĂ€ktskapsanalyser pĂ„ totalt 263 individer samt kartlagt tillvĂ€xt och parasitförekomst i torsk frĂ„n olika delar av Östersjön. Resultaten visar att den torsk som leker i Ålands hav kan vara genetiskt skild frĂ„n det sĂ„ kallade östra bestĂ„ndet som leker i södra Östersjön, Ă€ven om skillnaderna Ă€r smĂ„. En genetisk skillnad indikerar att det kan vara frĂ„ga om tvĂ„ bestĂ„nd som har ett begrĂ€nsat utbyte med varandra, alternativt att det endast Ă€r individer med en sĂ€rskild genuppsĂ€ttning som sprids frĂ„n Bornholm och ansamlas i Ålands hav. Individer frĂ„n Ålands hav har en högre tillvĂ€xt Ă€n torsk frĂ„n södra Östersjön, och saknar parasiten sĂ€lmask som Ă€r talrik i södra Östersjön. En sammanstĂ€llning av yrkesfiskets fĂ„ngster visar att man historiskt sett fĂ„ngat mycket torsk i Ålands hav, och att fĂ„ngsterna de senaste Ă„ren varit ökande i motsats till övriga delar av Östersjön. Sammantaget indikerar vĂ„ra resultat att torsken i Ålands hav kan utgöra ett separat lekbestĂ„nd. För att belĂ€gga detta behövs dock ytterligare studier i form av befruktningsexperiment i lĂ„g salthalt, kemiska analyser av fiskarnas hörselstenar samt fördjupad statistisk analys av det undersökta genetiska materialet. Ifall torsken i Ålands hav utgör ett lokalt reproducerande bestĂ„nd sĂ„ Ă€r det frĂ„ga om en unik anpassning till den lĂ„ga salthalten, och en separat förvaltning behövs för ett fortsatt uthĂ„lligt fiske

    Economic evaluation of occupational safety and health interventions from employers’ perspective : a systematic review

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    Objectives: The aim of this systematic review was to evaluate the cost-effectiveness of occupational safety and health interventions from the employer perspective. Methods: A comprehensive literature search (2005 to 2016) in five electronic databases was conducted. Pre-2005 studies were identified from the reference lists of previous studies and systematic reviews, which have similar objective to those of this search. Results: A total of 19 randomized controlled trials and quasi-experimental studies were included, targeting diverse health problems in a number of settings. Few studies included organizational-level interventions. When viewed in relation to the methodological quality and the sufficiency of economic evidence, five of 11 cost-effective occupational safety and health (OSH) interventions appear to be promising. Conclusion: The present systematic review highlights the need for high-quality economic evidence to evaluate the cost-effectiveness of OSH interventions, especially at organizational-level, in all areas of worker health
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