333 research outputs found

    Asymptotic description of solutions of the exterior Navier Stokes problem in a half space

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    We consider the problem of a body moving within an incompressible fluid at constant speed parallel to a wall, in an otherwise unbounded domain. This situation is modeled by the incompressible Navier-Stokes equations in an exterior domain in a half space, with appropriate boundary conditions on the wall, the body, and at infinity. We focus on the case where the size of the body is small. We prove in a very general setup that the solution of this problem is unique and we compute a sharp decay rate of the solution far from the moving body and the wall

    Screening for Obstructive Sleep Apnea in Adults: Evidence Report and Systematic Review for the US Preventive Services Task Force

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    Importance: Many adverse health outcomes are associated with obstructive sleep apnea (OSA). Objective: To review primary care-relevant evidence on screening adults for OSA, test accuracy, and treatment of OSA, to inform the US Preventive Services Task Force. Data Sources: MEDLINE, Cochrane Library, EMBASE, and trial registries through October 2015, references, and experts, with surveillance of the literature through October 5, 2016. Study Selection: English-language randomized clinical trials (RCTs); studies evaluating accuracy of screening questionnaires or prediction tools, diagnostic accuracy of portable monitors, or association between apnea-hypopnea index (AHI) and health outcomes among community-based participants. Data Extraction and Synthesis: Two investigators independently reviewed abstracts and full-text articles. When multiple similar studies were available, random-effects meta-analyses were conducted. Main Outcomes and Measures: Sensitivity, specificity, area under the curve (AUC), AHI, Epworth Sleepiness Scale (ESS) scores, blood pressure, mortality, cardiovascular events, motor vehicle crashes, quality of life, and harms. Results: A total of 110 studies were included (N = 46 188). No RCTs compared screening with no screening. In 2 studies (n = 702), the screening accuracy of the multivariable apnea prediction score followed by home portable monitor testing for detecting severe OSA syndrome (AHI ≥30 and ESS score >10) was AUC 0.80 (95% CI, 0.78 to 0.82) and 0.83 (95% CI, 0.77 to 0.90), respectively, but the studies oversampled high-risk participants and those with OSA and OSA syndrome. No studies prospectively evaluated screening tools to report calibration or clinical utility for improving health outcomes. Meta-analysis found that continuous positive airway pressure (CPAP) compared with sham was significantly associated with reduction of AHI (weighted mean difference [WMD], -33.8 [95% CI, -42.0 to -25.6]; 13 trials, 543 participants), excessive sleepiness assessed by ESS score (WMD, -2.0 [95% CI, -2.6 to -1.4]; 22 trials, 2721 participants), diurnal systolic blood pressure (WMD, -2.4 points [95% CI, -3.9 to -0.9]; 15 trials, 1190 participants), and diurnal diastolic blood pressure (WMD, -1.3 points [95% CI, -2.2 to -0.4]; 15 trials, 1190 participants). CPAP was associated with modest improvement in sleep-related quality of life (Cohen d, 0.28 [95% CI, 0.14 to 0.42]; 13 trials, 2325 participants). Mandibular advancement devices (MADs) and weight loss programs were also associated with reduced AHI and excessive sleepiness. Common adverse effects of CPAP and MADs included oral or nasal dryness, irritation, and pain, among others. In cohort studies, there was a consistent association between AHI and all-cause mortality. Conclusions and Relevance: There is uncertainty about the accuracy or clinical utility of all potential screening tools. Multiple treatments for OSA reduce AHI, ESS scores, and blood pressure. Trials of CPAP and other treatments have not established whether treatment reduces mortality or improves most other health outcomes, except for modest improvement in sleep-related quality of life

    Defrosting and cooking frozen meat: The effect of method of defrosting and of the manner and temperature of cooking upon weight loss and palatability

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    The primary objective of this study was to determine the time for defrosting cuts of beef, veal, Iamb and pork by four methods and to consider the effect of the method of defrosting upon the palatability of the cooked meat. The methods of defrosting were: (1) in the refrigerator, (2) at room temperature, (3) in water and (4) during cooking. Data to determine the weight loss during defrosting, weight loss during cooking, time for cooking and the amount of fuel needed for cooking were also recorded. The methods of cooking employed with the different cuts of meat were roasting, broiling, pan-broiling, pan-frying, deep-fat frying, braising and cooking in water. More than one cooking temperature was used for most of the cooking methods

    A rigorous implementation of the Jeans--Landau--Teller approximation

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    Rigorous bounds on the rate of energy exchanges between vibrational and translational degrees of freedom are established in simple classical models of diatomic molecules. The results are in agreement with an elementary approximation introduced by Landau and Teller. The method is perturbative theory ``beyond all orders'', with diagrammatic techniques (tree expansions) to organize and manipulate terms, and look for compensations, like in recent studies on KAM theorem homoclinic splitting.Comment: 23 pages, postscrip

    Associations between neck musculoskeletal complaints and work related factors among public service computer workers in Kaunas

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    Objectives:Information technologies have been developing very rapidly, also in the case of occupational activities. Epidemiological studies have shown that employees, who work with computers, are more likely to complain of musculoskeletal disorders (MSD). The aim of this study was to evaluate associations between neck MSD and individual and work related factors. Materials and Methods: The investigation which consisted of two parts - a questionnaire study (using Nordic Musculoskeletal questionnaire and Copenhagen Psychosocial Questionnaire) and a direct observation (to evaluate ergonomic work environment using RULA method) was carried out in three randomly selected public sector companies of Kaunas. The study population consisted of 513 public service office workers. Results: The survey showed that neck MSDs were very common in the investigated population. The prevalence rate amounted to 65.7%. According to our survey neck MSDs were significantly associated with older age, bigger work experience, high quantitative and cognitive job demands, working for longer than 2 h without taking a break as well as with higher ergonomic risk score. The fully adjusted model working for longer than 2 h without taking a break had the strongest associations with neck complaints. Conclusion: It was confirmed, that neck MSDs were significantly associated with individual factors as well as conditions of work, therefore, preventive acions against neck complaints should be oriented at psychosocial and ergonomic work environment as well as at individual factors

    Cerebral activations related to ballistic, stepwise interrupted and gradually modulated movements in parkinson patients

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    Patients with Parkinson's disease (PD) experience impaired initiation and inhibition of movements such as difficulty to start/stop walking. At single-joint level this is accompanied by reduced inhibition of antagonist muscle activity. While normal basal ganglia (BG) contributions to motor control include selecting appropriate muscles by inhibiting others, it is unclear how PD-related changes in BG function cause impaired movement initiation and inhibition at single-joint level. To further elucidate these changes we studied 4 right-hand movement tasks with fMRI, by dissociating activations related to abrupt movement initiation, inhibition and gradual movement modulation. Initiation and inhibition were inferred from ballistic and stepwise interrupted movement, respectively, while smooth wrist circumduction enabled the assessment of gradually modulated movement. Task-related activations were compared between PD patients (N = 12) and healthy subjects (N = 18). In healthy subjects, movement initiation was characterized by antero-ventral striatum, substantia nigra (SN) and premotor activations while inhibition was dominated by subthalamic nucleus (STN) and pallidal activations, in line with the known role of these areas in simple movement. Gradual movement mainly involved antero-dorsal putamen and pallidum. Compared to healthy subjects, patients showed reduced striatal/SN and increased pallidal activation for initiation, whereas for inhibition STN activation was reduced and striatal-thalamo-cortical activation increased. For gradual movement patients showed reduced pallidal and increased thalamo-cortical activation. We conclude that PD-related changes during movement initiation fit the (rather static) model of alterations in direct and indirect BG pathways. Reduced STN activation and regional cortical increased activation in PD during inhibition and gradual movement modulation are better explained by a dynamic model that also takes into account enhanced responsiveness to external stimuli in this disease and the effects of hyper-fluctuating cortical inputs to the striatum and STN in particular

    Prevention of recurrent sickness absence among employees with common mental disorders: design of a cluster-randomised controlled trial with cost-benefit and effectiveness evaluation

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    BACKGROUND: Common mental disorders, such as depression, anxiety disorder, and adjustment disorder, have emerged as a major public and occupational health problem in many countries. These disorders can have severe consequences such as absenteeism and work disability. Different interventions have been developed to improve the return-to-work of employees with common mental disorders, but still a large proportion of employees experiences health and work problems after their return-to-work. For this reason, the SHARP-at work intervention is developed to prevent a relapse of sickness absence among employees who have returned to work after a period of sickness absence because of common mental disorders. We aim to evaluate the effectiveness, cost-benefit and process of the intervention compared to care as usual. METHODS/DESIGN: The study is designed as a cluster-randomised controlled trial with randomisation at the level of the occupational physician. Employees who have returned to work after a period of sickness absence because of a common mental disorder are included in the study. Employees in the intervention group will receive the SHARP-at work intervention. The intervention focusses on active guidance of employees by occupational physicians during the first weeks of work after sickness absence. Employees in the control group will receive care as usual. Outcomes will be assessed at baseline and at 3, 6, and 12 months follow-up. The primary outcome is cumulative recurrent sickness absence days. Secondary outcome measures are mental health, work functioning, and coping. Adherence to the protocol, communication between stakeholders, and satisfaction with the treatment are the process measures assessed in both study groups. Cost-benefit is calculated from a societal perspective. Finally, prognostic factors for a relapse of sickness absence are investigated. DISCUSSION: This study goes beyond return-to-work by focussing on the prevention of recurrent sickness absence. The study incorporates not only outcomes on sickness absence and mental health but also on health-related work functioning. The results of this study can contribute to a further development of practice guidelines and the promotion of sustainable work participation. TRIAL REGISTRATION: NTR1963

    A prospective study of cumulative job stress in relation to mental health

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    BACKGROUND: This study tests associations between psychosocial stress at work measured by the effort-reward imbalance model in a dynamic perspective, and multiple indicators of poor mental health, in a prospective design. METHODS: 1986 male and female employees from four Belgian enterprises were followed-up over one year within the framework of the Somstress study. Based on two consecutive measurements, an index of cumulative job stress was constructed and its associations with five indicators of mental health were studied, excluding caseness at entry (for depression, anxiety, somatisation, chronic fatigue and psychotropic drug consumption respectively). Taking into account the longitudinal design, four categories of job stress are defined: 1) employees free from stress at both measures, 2) job stress present at first measure but not at the second one, 3) recent onset of job stress as evidenced by second measure 4) workers exposed to stress at both measures. Multivariate logistic regression with appropriate adjustments was applied. RESULTS: In bivariate analysis, a clear graded association of cumulative job stress with all five mental health indicators is observed, both in men and women. In multivariate logistic regression analysis, recent onset of stress is strongly associated with poor mental health among men (odds ratios ranging from 1.8 to 4.6), while cumulative stress shows strongest effects on mental health in women (odds ratios ranging from 1.4 to 7.1). CONCLUSION: Cumulative experience and recent onset of job stress in terms of high effort spent and low reward received is associated with elevated risk of all five indicators of poor mental health at follow-up in a large cohort of employees
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