1,066 research outputs found

    Implementation of Fiber Optic Sensing System on Sandwich Composite Cylinder Buckling Test

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    The National Aeronautics and Space Administration (NASA) Engineering and Safety Center Shell Buckling Knockdown Factor Project is a multicenter project tasked with developing new analysis-based shell buckling design guidelines and design factors (i.e., knockdown factors) through high-fidelity buckling simulations and advanced test technologies. To validate these new buckling knockdown factors for future launch vehicles, the Shell Buckling Knockdown Factor Project is carrying out structural testing on a series of large-scale metallic and composite cylindrical shells at the NASA Marshall Space Flight Center (Marshall Space Flight Center, Alabama). A fiber optic sensor system was used to measure strain on a large-scale sandwich composite cylinder that was tested under multiple axial compressive loads up to more than 850,000 lb, and equivalent bending loads over 22 million in-lb. During the structural testing of the composite cylinder, strain data were collected from optical cables containing distributed fiber Bragg gratings using a custom fiber optic sensor system interrogator developed at the NASA Armstrong Flight Research Center. A total of 16 fiber-optic strands, each containing nearly 1,000 fiber Bragg gratings, measuring strain, were installed on the inner and outer cylinder surfaces to monitor the test article global structural response through high-density real-time and post test strain measurements. The distributed sensing system provided evidence of local epoxy failure at the attachment-ring-to-barrel interface that would not have been detected with conventional instrumentation. Results from the fiber optic sensor system were used to further refine and validate structural models for buckling of the large-scale composite structures. This paper discusses the techniques employed for real-time structural monitoring of the composite cylinder for structural load introduction and distributed bending-strain measurements over a large section of the cylinder by utilizing unique sensing capabilities of fiber optic sensors

    Family functioning at meals relates to adherence in young children with type 1 diabetes

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    This study examined associations between mealtime family functioning, dietary adherence and glycaemic control in young children with type 1 diabetes mellitus (T1DM). We hypothesised that poorer family functioning would correlate with poorer dietary adherence and glycaemic control.Thirty-five families of children (M = 5.6 ± 1.5 years) with T1DM had meals videotaped in their home, which were coded for family functioning according to the McMaster Interaction Coding System. Children's dietary adherence was assessed according to deviations from the prescribed number of carbohydrate units per meal and recommended carbohydrate intake levels per day. Glycaemic control was measured via 14 days of self-monitoring of blood glucose levels.Findings demonstrated significant negative associations between children's dietary adherence and two dimensions of family functioning: Task Accomplishment ( r =−0.43, P = 0.03) and Behavioral Control ( r =−0.54, P = 0.00). Affect Management correlated negatively with the percent of blood glucose levels below the normal range ( r =−0.33, P = 0.05). Eleven families (31%) of young children with type 1 diabetes demonstrated mealtime family functioning in the unhealthy range.This was the first study to examine the relationship between mealtime family functioning and children's dietary adherence and glycaemic control in families of young children with T1DM. Previous research has found mealtime family functioning to be impaired in families of young children with T1DM when compared with families of children without diabetes. Research is needed to determine if family functioning and dietary adherence can be improved via specific family-based behavioural training around mealtimes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78579/1/j.1440-1754.2009.01604.x.pd

    Alcohol Consumption and Dietary Patterns: The FinDrink Study

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    The aim of this population-based study was to investigate differences in dietary patterns in relation to the level of alcohol consumption among Finnish adults. This study was part of the FinDrink project, an epidemiologic study on alcohol use among Finnish population. It utilized data from the Kuopio Ischaemic Heart Disease Risk Factor Study. A total of 1720 subjects comprising of 816 men and 904 women aged 53–73 years were included in the study in 1998–2001. Food intake was collected via a 4-day food diary method. Self-reported alcohol consumption was assessed with quantity-frequency method based on the Nordic Alcohol Consumption Inventory. Weekly alcohol consumption was categorized into three groups: non-drinkers (<12 grams), moderate drinkers (12–167.9 grams for men, 12–83.9 grams for women) and heavy drinkers (≄168 grams for men, ≄84 grams for women). Data were analyzed for men and women separately using multiple linear regression models, adjusted for age, occupational status, marital status, smoking, body mass index and leisure time physical activity. In women, moderate/heavy drinkers had lower fibre intake and moderate drinkers had higher vitamin D intake than non-drinkers. Male heavy drinkers had lower fibre, retinol, calcium and iron intake, and moderate/heavy drinkers had higher vitamin D intake than non-drinkers. Fish intake was higher among women moderate drinkers and men moderate/heavy drinkers than non-drinkers. In men, moderate drinkers had lower fruit intake and heavy drinkers had lower milk intake than non-drinkers. Moderate drinkers had higher energy intake from total fats and monosaturated fatty acids than non-drinkers. In contrast, energy intake from carbohydrates was lower among moderate/heavy drinkers than non-drinkers. In conclusion, especially male heavy drinkers had less favorable nutritional intake than moderate and non-drinkers. Further studies on the relationship between alcohol consumption and dietary habits are needed to plan a comprehensive dietary intervention programs in future

    Optimization of skeletal configuration: Studies of scoliosis correction biomechanics

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    A scheme for optimizing configurations in models of skeletal structures is presented. Use of the scheme is illustrated through determination of biomechanically optimal correction of a right-thoracic scoliosis by passive brace and active muscle forces. The locations and magnitudes of the passive brace forces, and the trunk muscle groups and their corresponding contraction intensity magnitudes that would optimally correct the geometric deformities of the spine were determined. The results suggest that, from a biomechanical viewpoint, both brace and muscle forces are capable of substantial correction of a model thoracic scoliosis. However, comparison of model results with long-term clinical results suggests that even under optimal conditions it is unlikely that scoliosis can be fully corrected by passive brace forces or active muscle contractions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29641/1/0000730.pd

    Corticosterone and dopamine D2/D3 receptors mediate the motivation for voluntary wheel running in C57BL/6J mice

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    Physical exercise can improve cognition but whether this is related to motivation levels is unknown. Voluntary wheel running is a rewarding activity proposed as a model of motivation to exercise. To question the potential effects of exercise motivation on subsequent behaviour, we used a pharmacological approach targeting some reward mechanisms. The stress hormone corticosterone has rewarding effects mediated by activation of low affinity glucocorticoid receptors (GR). To investigate whether corticosterone synthesis motivates exercise via activation of GRs and subsequently, impacts on behaviour, we treated C57BL/6J mice acutely with the inhibitor of corticosterone synthesis metyrapone (35 mg/kg) or repeatedly with the GR antagonist mifepristone (30 mg/kg) prior to 1-h running wheel sessions. To investigate whether reducing motivation to exercise impacts on behaviour, we antagonised running-induced dopamine D2/D3 receptors activation with sulpiride (25 or 50 mg/kg) and assessed locomotor, anxietyrelated and memory performance after 20 running sessions over 4 weeks. We found that corticosterone synthesis contributes to running levels, but the maintenance of running behaviour was not mediated by activation of GRs. Intermittent exercise was not associated with changes in behavioural or cognitive performance. The persistent reduction in exercise levels triggered by sulpiride also had limited impact on behavioural performance, although the level of performance for some behaviours was related to the level of exercise. Altogether, these findings indicate that corticosterone and dopamine D2/D3 receptor activation contribute to the motivation for wheel running, but suggest that motivation for exercise is not a sufficient factor to alter behaviour in healthy mice

    Evidence-based Kernels: Fundamental Units of Behavioral Influence

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    This paper describes evidence-based kernels, fundamental units of behavioral influence that appear to underlie effective prevention and treatment for children, adults, and families. A kernel is a behavior–influence procedure shown through experimental analysis to affect a specific behavior and that is indivisible in the sense that removing any of its components would render it inert. Existing evidence shows that a variety of kernels can influence behavior in context, and some evidence suggests that frequent use or sufficient use of some kernels may produce longer lasting behavioral shifts. The analysis of kernels could contribute to an empirically based theory of behavioral influence, augment existing prevention or treatment efforts, facilitate the dissemination of effective prevention and treatment practices, clarify the active ingredients in existing interventions, and contribute to efficiently developing interventions that are more effective. Kernels involve one or more of the following mechanisms of behavior influence: reinforcement, altering antecedents, changing verbal relational responding, or changing physiological states directly. The paper describes 52 of these kernels, and details practical, theoretical, and research implications, including calling for a national database of kernels that influence human behavior

    Measurement and interpretation of same-sign W boson pair production in association with two jets in pp collisions at s = 13 TeV with the ATLAS detector

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    This paper presents the measurement of fducial and diferential cross sections for both the inclusive and electroweak production of a same-sign W-boson pair in association with two jets (W±W±jj) using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity diference. The measured fducial cross sections for electroweak and inclusive W±W±jj production are 2.92 ± 0.22 (stat.) ± 0.19 (syst.)fb and 3.38±0.22 (stat.)±0.19 (syst.)fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confdence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons H±± that are produced in vector-boson fusion processes and decay into a same-sign W boson pair is performed. The largest deviation from the Standard Model occurs for an H±± mass near 450 GeV, with a global signifcance of 2.5 standard deviations
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