8,386 research outputs found

    Mg-Ni-H films as selective coatings: tunable reflectance by layered hydrogenation

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    Unlike other switchable mirrors, Mg2NiHx films show large changes in reflection that yield very low reflectance (high absorptance) at different hydrogen contents, far before reaching the semiconducting state. The resulting reflectance patterns are of interference origin, due to a self-organized layered hydrogenation mechanism that starts at the substrate interface, and can therefore be tuned by varying the film thickness. This tunability, together with the high absorptance contrast observed between the solar and the thermal energies, strongly suggests the use of these films in smart coatings for solar applications.Comment: Three two-column pages with 3 figures embedded; RevTE

    Longitudinal relationships between lifestyle and cardiovascular and bone health status indicators in males and females between 13 and 27 years of age: a review of findings from the Amsterdam Growth and Health Longitudinal Study

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    UNLABELLED: The Amsterdam Growth and Health Longitudinal Study is longitudinal co-hort study on 181 males and females initially aged 13 years, with follow-up measurements at ages 14, 15, 16, 21 and 27 years. METHODS: Anthropometrical, biological and lifestyle parameters, and age 27 also bone mineral density (BMD) of the lumbar spine (L2-L4), were measured repeatedly. Adolescent dietary intake and physical activity was related to adult cardiovascular and bone health status indicators by MLR; longitudinal relationships between physical activity and dietary intake, and cardiovascular health status indicators were assessed hy GEE-analysis. RESULTS: Adolescent physical activity was not related to most of the indicators of adult cardiovascular health status, with the exception of a positive relationship with the waist-to-hip in females; in males 'energetic' adolescent physical activity contributed significantly to adult BMD; both in males and females, when taking the entire longitudinal period into account, peak strain physical activity was a relatively more important predictor of adult BMD than 'energetic' physical activity; calcium intake during adolescence was not a significant predictor of bone health status measured at age 27, both in males and females; a consistent significant positive longitudinal relationship was found between physical activity and serum HDL-cholesterol and significant negative longitudinal relationships were found with the subscapular skinfold and with body fat mass; a positive longitudinal relationship was found between serum total cholesterol (TC) and cholesterol intake, saturated fat (SFA) intake and the Keys-score; a negative longitudinal relationship was found between TC and polyunsaturated fit and total energy intake; for HDL a positive longitudinal relationship was found with SFA intake; low tracking was found for physical (in-) activity and dietary intake variables

    Dropout from exercise programs for seniors: a prospective cohort study

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    This study examines dropout incidence, moment of dropout, and switching behavior in organized exercise programs for seniors in the Netherlands, as determined in a prospective cohort study (with baseline measurements at the start of the exercise program and follow-up after 6 months; N = 1,725, response rate 73%). Participants were community-living individuals 50+ who participated in different forms of organized exercise programs. The average dropout incidence was 0.15 per 6 months, which is lower than that for the general population. The dropout incidence and the timing of dropout differed substantially between the exercise programs. In total, 31% of people who dropped out of one type of exercise program switched to another type of exercise. The type of program and exercise had a strong effect on differences in this switching behavior. It is recommended that switching behavior be monitored in future studie

    Surface state charge dynamics of a high-mobility three dimensional topological insulator

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    We present a magneto-optical study of the three-dimensional topological insulator, strained HgTe using a technique which capitalizes on advantages of time-domain spectroscopy to amplify the signal from the surface states. This measurement delivers valuable and precise information regarding the surface state dispersion within <1 meV of the Fermi level. The technique is highly suitable for the pursuit of the topological magnetoelectric effect and axion electrodynamics.Comment: Published version, online Sept 23, 201

    The design of a real-time formative evaluation of the implementation process of lifestyle interventions at two worksites using a 7-step strategy (BRAVO@Work)

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    <p>Abstract</p> <p>Background</p> <p>Worksite health promotion programs (WHPPs) offer an attractive opportunity to improve the lifestyle of employees. Nevertheless, broad scale and successful implementation of WHPPs in daily practice often fails. In the present study, called BRAVO@Work, a 7-step implementation strategy was used to develop, implement and embed a WHPP in two different worksites with a focus on multiple lifestyle interventions.</p> <p>This article describes the design and framework for the formative evaluation of this 7-step strategy under real-time conditions by an embedded scientist with the purpose to gain insight into whether this this 7-step strategy is a useful and effective implementation strategy. Furthermore, we aim to gain insight into factors that either facilitate or hamper the implementation process, the quality of the implemented lifestyle interventions and the degree of adoption, implementation and continuation of these interventions.</p> <p>Methods and design</p> <p>This study is a formative evaluation within two different worksites with an embedded scientist on site to continuously monitor the implementation process. Each worksite (i.e. a University of Applied Sciences and an Academic Hospital) will assign a participating faculty or a department, to implement a WHPP focusing on lifestyle interventions using the 7-step strategy. The primary focus will be to describe the natural course of development, implementation and maintenance of a WHPP by studying [a] the use and adherence to the 7-step strategy, [b] barriers and facilitators that influence the natural course of adoption, implementation and maintenance, and [c] the implementation process of the lifestyle interventions. All data will be collected using qualitative (i.e. real-time monitoring and semi-structured interviews) and quantitative methods (i.e. process evaluation questionnaires) applying data triangulation. Except for the real-time monitoring, the data collection will take place at baseline and after 6, 12 and 18 months.</p> <p>Discussion</p> <p>This is one of the few studies to extensively and continuously monitor the natural course of the implementation process of a WHPP by a formative evaluation using a mix of quantitative and qualitative methods on different organizational levels (i.e. management, project group, employees) with an embedded scientist on site.</p> <p>Trial Registration</p> <p>NTR2861</p

    Physical risk factors for neck pain.

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    To identify physical risk factors for neck pain, a systematic review of the literature was carried out. Based on methodological quality and study design, 4 levels of evidence were defined to establish the strength of evidence for the relationship between risk factors and neck pain. Altogether, 22 cross-sectional studies, 2 prospective cohort studies, and 1 case-referent study were eligible for determining the level of evidence. The results showed some evidence for a positive relationship between neck pain and the duration of sitting and twisting or bending of the trunk. A sensitivity analysis was carried out excluding 3 items of the quality list, the importance of which seemed doubtful. On the basis of this sensitivity analysis, it was concluded that there is some evidence for a positive relationship between neck pain and the following work-related risk factors: neck flexion, arm force, arm posture, duration of sitting, twisting or bending of the trunk, hand-arm vibration, and workplace design

    Effect of unsupervised home based proprioceptive training on recurrences of ankle sprain: randomised controlled trial

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    Objective To evaluate the effectiveness of an unsupervised proprioceptive training programme on recurrences of ankle sprain after usual care in athletes who had sustained an acute sports related injury to the lateral ankle ligament
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