562 research outputs found

    Application of DOT-MORSE coupling to the analysis of three-dimensional SNAP shielding problems

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    The use of discrete ordinates and Monte Carlo techniques to solve radiation transport problems is discussed. A general discussion of two possible coupling schemes is given for the two methods. The calculation of the reactor radiation scattered from a docked service and command module is used as an example of coupling discrete ordinates (DOT) and Monte Carlo (MORSE) calculations

    Inelastic Neutron Scattering from Pressurized Ethane

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    Motions of the ethane molecule have been investigated at room temperature by inelastic neutron scattering techniques. Ethane targets were observed both in the gas and liquid phases by means of pressure variation. The University of Michigan four‐rotor mechanical monochromator was used to obtain data at scattering angles of 90 and 22 deg for neutron energies in the range 0.046 to 0.020 eV. Triple‐axis‐crystal spectrometer measurements were also made at 0.035 and 0.064 eV as verification. These data indicate that there is no significant difference in the scattering properties of ethane in the gas and liquid state. Effects of the torsional motion of the two methyl groups about the C☒C bond can be seen in the forward‐angle data. Comparison of experiment with theory indicates that a Krieger—Nelkin model which includes a harmonic‐oscillator representation of the torsional motion approximately predicts the observed data. The influence of multiple scattering on the final energy distribution has been observed and is discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70244/2/JCPSA6-43-11-4134-1.pd

    Exploration of the mechanisms of change in constructs from self-determination theory and quality of life during a multidisciplinary family-based intervention for overweight adolescents

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    The current study explored whether a multidisciplinary family-based intervention underpinned by self-determination theory could enhance perceptions of parent need support, autonomous motivation, and quality of life in overweight and obese adolescents. Using a staggered-entry waitlist-period control design, adolescents (n = 56) were assessed at baseline and preintervention (within-participant control), immediately following intervention, and at 3, 6, and 12 month follow-ups. Parents were trained in need-supportive behaviors within the broader context of an 8-week multidisciplinary intervention attended jointly with adolescents. Following intervention, significant improvements were demonstrated in adolescent perceptions of parent need support, autonomous motivation, and quality of life, and changes were maintained at the 1-year follow-up. Mediation analyses revealed changes in perceptions of parent need support predicted changes in quality of life indirectly via changes in autonomous motivation. Findings suggest overweight and obese adolescents are likely to benefit from multidisciplinary family-based interventions that aim to train parents in need-supportive behaviors

    Does a classroom standing desk intervention modify standing and sitting behaviour and musculoskeletal symptoms during school time and physical activity during waking time?

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    © 2018 by the authors. Licensee MDPI, Basel, Switzerland. Children are increasingly spending more time sedentary at school and during leisure time. This study examined the effects of a standing desk intervention in a classroom on children’s standing and sitting time at school, sedentary and physical activity levels throughout the day (waking hours), and musculoskeletal discomfort. A within-subjects crossover study design was used. Participants used either a standing desk or traditional seated desk for 21 days before swapping desks for another 21 days. Accelerometry and musculoskeletal discomfort data were collected during the last seven days of each 21-day period. Mixed models were used to analyse accelerometry data. Zero-inflated regression models and logistic regression models were used to analyse discomfort data. Forty-seven male students (aged 10–11 years) participated in the study. Standing time was 21 min/school day higher (p < 0.001) and sitting time was 24 min/school day lower (p = 0.003) when standing desks were used. No significant differences were found in sedentary and physical activity time during waking hours between the standing desk and seated desk conditions. Students were less likely to report musculoskeletal discomfort in the neck, shoulder, elbows and lower back when using standing desks (OR 0.52–0.74). Standing desks significantly increased classroom standing time and decreased musculoskeletal discomfort reports but had no overall effect on daily physical activity levels. Schools should consider moving towards classrooms enabling a variety of postures to potentially improve the long-term health of children

    The short term musculoskeletal and cognitive effects of prolonged sitting during office computer work

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    Office workers are exposed to high levels of sedentary time. In addition to cardio-vascular and metabolic health risks, this sedentary time may have musculoskeletal and/or cognitive impacts on office workers. Participants (n = 20) undertook two hours of laboratory-based sitting computer work to investigate changes in discomfort and cognitive function (sustained attention and problem solving), along with muscle fatigue, movement and mental state. Over time, discomfort increased in all body areas (total body IRR [95% confidence interval]: 1.43 [1.33–1.53]) reaching clinically meaningful levels in the low back and hip/thigh/buttock areas. Creative problem solving errors increased (ß = 0.25 [0.03–1.47]) while sustained attention did not change. There was no change in erector spinae, trapezius, rectus femoris, biceps femoris and external oblique median frequency or amplitude; low back angle changed towards less lordosis, pelvis movement increased, and mental state deteriorated. There were no substantial correlations between discomfort and cognitive function. The observed changes suggest prolonged sitting may have consequences for musculoskeletal discomfort and cognitive function and breaks to interrupt prolonged sitting are recommended

    Active video games: An opportunity for enhanced learning and positive health effects?

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    Active video games are an emerging genre of electronic games that provide engaging exercise experiences by combining physical exertion with interactive game play. As such they have attracted increased interest from health promotion professionals to reduce sedentary behavior, increase physical activity, and improve health outcomes such as body composition. However their potential for enhancing the educational experience has not been extensively explored. This paper provides a brief overview of active video game research to date and outlines opportunities for future research. Specifically, we highlight the need to develop a conceptual framework to better understand the determinants, mediators, moderators, and consequences of active video gaming and integrate learning and health outcomes. We propose that active video games can be a key part of a wider “digital” supportive environment where education and health researchers and professionals work with, rather than against, video game technologies to promote learning and health

    An exploration of familial associations in spinal posture defined using a clinical grouping method

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    The primary aim of this study was to examine familial associations in spinal posture, defined using postural angles and a clinical classification method. A secondary aim was to investigate the reliability of clinical postural classification. Postural angles were calculated from sagittal photographs, while two experienced clinicians made use of standing sagittal images to classify participants into one of four postural groups (sway, flat, hyperlordotic, neutral). Parent-child associations in postural angles and postural groups were evaluated using Pearson\u27s correlation and Fisher\u27s exact test, respectively. Inter-rater reliability was expressed using percentage agreement and Kappa coefficients (K). Daughters whose father or mother had a hyperlordotic posture were 4.0 or 3.5 times, respectively, more likely to have a hyperlordotic posture than daughters whose parents did not have a hyperlordotic posture. These participants in the hyperlorotic group had a significantly higher body mass index than members of the other postural groups (p \u3c 0.03). Percentage agreement between clinicians was 63.5% (K = 0.48). These results provide preliminary evidence of a familial association in the hyperlordotic posture and support the use of postural classification. (C) 2011 Elsevier Ltd. All rights reserved

    Inflammatory myofibroblastic tumour of the gallbladder

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    BACKGROUND: Inflammatory myofibroblastic tumour (IMT) is a benign, nonmetastasizing proliferation of myofibroblasts with a potential for local infiltration, recurrence and persistent local growth. CASE REPORT: We report a case of a 51 year-old female, who had excision of a gallbladder tumour. Histopathology showed it to be IMT of the gallbladder. CONCLUSION: The approach to these tumours should be primarily surgical resection to obtain a definitive diagnosis and relieve symptoms. IMT has a potential for local infiltration, recurrence and persistent local growth

    An exploration of familial associations of two movement pattern-derived subgroups of chronic disabling low back pain; a cross-sectional cohort study

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    © 2016 Elsevier Ltd. Background: Altered movement patterns with pain have been demonstrated in children, adolescents and adults with chronic disabling low back pain (CDLBP). A previously developed classification system has identified different subgroups including active extension and multidirectional patterns in patients with CDLBP. While familial associations have been identified for certain spinal postures in standing, it is unknown whether a familial relationship might exist between movement pattern-derived subgroups in families with CDLBP. Objectives: This study explored whether familial associations in movement pattern-derived subgroups within and between members of families with CDLBP existed. Design: Cross-sectional cohort study. Method: 33 parents and 28 children with CDLBP were classified into two subgroups based on clinical analysis of video footage of postures and functional movements, combined with aggravating factors obtained from Oswestry Disability Questionnaire. Prevalence of subgroups within family members was determined, associations between parent and child's subgroup membership was evaluated using Fisher's exact test, and spearman's correlation coefficient was used to determine the strength of association between familial dyads. Results: The majority of parents were classified as active extenders, sons predominately multidirectional and daughters were evenly distributed between the two subgroups. No significant association was found when comparing subgroups in nine parent-child relationships. Conclusions: The exploration of a small cohort of family dyads in this study demonstrated that children's movement pattern-derived subgroups could not be explained by their parents' subgroup membership. These results cannot be generalised to the CLBP population due to this study's small sample. Larger sample studies are needed to further elucidate this issue
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