132 research outputs found

    NASTRAN analysis for the Airmass Sunburst model 'C' Ultralight Aircraft

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    The purpose of this project was to create a three dimensional NASTRAN model of the Airmass Sunburst Ultralight comparable to one made for finite element analysis. A two dimensional sample problem will be calculated by hand and by NASTRAN to make sure that NASTRAN finds similar results. A three dimensional model, similar to the one analyzed by the finite element program, will be run on NASTRAN. A comparison will be done between the NASTRAN results and the finite element program results. This study will deal mainly with the aerodynamic loads on the wing and surrounding support structure at an attack angle of 10 degrees

    Correlates of meeting the physical activity, sedentary behavior, and sleep guidelines for the early years among Belgian preschool children: the toybox-study

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    Physical activity, sedentary behavior, and sleep guidelines for preschool children were already established and integrated into the 24 h movement behavior guidelines in 2017. The aim of the current study was to investigate correlates of meeting or not meeting the physical activity, sedentary behavior, and sleep guidelines in Belgian preschool children. In total, 595 preschool children (53.3% boys, 46.7% girls, mean age: 4.2 years) provided complete data for the three behaviors and potentially associated correlates. Physical activity was objectively measured with accelerometers. Screen time, sleep duration, and correlates were reported by parents with the use of a questionnaire. Backward logistic regression was used to identify factors associated with meeting all guidelines for weekdays and weekend days. In the final model, older preschoolers (OR = 1.89), having a normal weight compared to being underweight (OR = 0.30), having parents that do not watch a lot of television (OR = 0.99), and having a father that attained higher education (OR = 1.91) were associated with meeting all guidelines on weekdays. For weekend days, a significant association was found for attending a sports club (OR = 1.08). Overall, only a few factors were associated with meeting the guidelines. A more comprehensive measurement of preschool children's potential correlates of physical activity, sedentary behavior, and sleep is warranted

    Using the intervention mapping protocol to reduce European preschoolers' sedentary behavior, an application to the ToyBox-study

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    Background: High levels of sedentary behavior are often measured in preschoolers, but only a few interventions have been developed to counteract this. Furthermore, detailed descriptions of interventions in preschoolers targeting different forms of sedentary behavior could not be located in the literature. The aim of the present paper was to describe the different steps of the Intervention Mapping Protocol used towards the development of an intervention component of the ToyBox-study focusing on decreasing preschoolers' sedentary behavior. The ToyBox-study focuses on the prevention of overweight in 4- to 6-year-old children by implementing a multi-component kindergarten-based intervention with family involvement in six different European countries. Methods: Applying the Intervention Mapping Protocol, six different steps were systematically completed for the structured planning and development of the intervention. A literature search and results from focus groups with parents/caregivers and kindergarten teachers were used as a guide during the development of the intervention and the intervention materials. Results: The application of the different steps in the Intervention Mapping Protocol resulted in the creation of matrices of change objectives, followed by the selection of practical applications for five different intervention tools that could be used at the individual level of the preschool child, at the interpersonal level (i.e., parents/caregivers) and at the organizational level (i.e., kindergarten teachers). No cultural differences regarding preschoolers' sedentary behavior were identified between the participating countries during the focus groups, so cultural and local adaptations of the intervention materials were not necessary to improve the adoption and implementation of the intervention. Conclusions: A systematic and evidence-based approach was used for the development of this kindergarten-based family-involved intervention targeting preschoolers, with the inclusion of parental involvement. The application of the Intervention Mapping Protocol may lead to the development of more effective interventions. The detailed intervention matrices that were developed as part of the ToyBox-study can be used by other researchers as an aid in order to avoid repetitive work for the design of similar interventions

    Combining effect and process evaluation on European preschool children’s snacking behavior in a kindergarten-based, family-involved cluster randomized controlled trial : the ToyBox study

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    This study aimed at (1) studying the effect of the standardized ToyBox intervention on European preschoolers' snacking behavior, and (2) studying whether a higher process evaluation score from teachers and parents/caregivers was associated with a more positive result for preschoolers' snack intake. A sample of 4970 preschoolers (51.4% boys, 4.74 +/- 0.44 years) from six European countries provided information on snack intake with the use of a Food Frequency Questionnaire. To investigate the effect of the intervention, multilevel repeated measures analyses were executed for the total sample and the six country-specific samples. Furthermore, questionnaires to measure process evaluation were used to compute a total process evaluation score for teachers and parents/caregivers. No significant intervention effects on preschoolers' snack intake were found (all p > 0.003). In general, no different effects of the intervention on snack intake were found according to kindergarten teachers' and parents'/caregivers' process evaluation scores. The lack of effects could be due to limited intervention duration and dose. To induce larger effects on preschoolers' snack intake, a less standardized intervention which is more tailored to the local needs might be needed

    Objectively measured sedentary time and physical activity time across the lifespan: a cross-sectional study in four age groups

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    BACKGROUND: From a health perspective it is suggested to promote a positive balance between time spent in light intensity physical activity (LIPA) and sedentary behaviour (SB) (i.e. spending more time in LIPA than time spent in SB). However, no studies have reported prevalence rates of the LIPA-SB balance yet. The aim of this study was to objectively investigate the time spent in SB, in LIPA and moderate-to-vigorous intensity physical activity (MVPA) in four Belgian age groups and to explore which proportion of the population had a favorable balance between LIPA and SB and combined this with recommended amount of MVPA. METHODS: Accelerometer data from 7 cross-sectional studies (N=2083) in four age groups (preschoolers, primary schoolchildren, secondary schoolchildren and adults) were aggregated. Differences in SB and PA between age groups and between men and women were determined by two-way MANCOVA. LIPA-SB balance was calculated and participants were categorized into one of four groups: (1) positive LIPA-SB balance (LIPA> SB) & sufficient MVPA (2) negative LIPA-SB balance & sufficient MVPA (3) positive LIPA-SB balance & insufficient MVPA (4) negative LIPA-SB balance & insufficient MVPA. RESULTS: For the total sample, 55% of the waking time was spent in SB, 39% in LIPA and 6% in MVPA. Differences in SB between age groups was dependent from gender (p<0.001). Further, a positive LIPA-SB balance was assessed in 18% of the total sample and only 10% combined this positive balance with recommended amount of MVPA. Secondary schoolgirls were most at risk, with only 1% of the sample combining a positive LIPA-SB balance with sufficient MVPA. Another risk group was the large proportion (43%) of adult men who combined sufficient MVPA with a negative LIPA-SB balance. CONCLUSION: A high proportion of the Belgian population is at risk if taking into account both SB and PA levels. Secondary schoolgirls have the unhealthiest SB and PA profile and are therefore an important target group for interventions both increasing MVPA and decreasing SB. In men more attention should be given in promoting a positive LIPA-SB balance independently from their compliance with the MVPA guidelines

    Using the intervention mapping protocol to develop a community-based intervention for the prevention of childhood obesity in a multi-centre European project: the IDEFICS intervention

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    Background: The prevalence of childhood obesity has increased during the past decades and is now considered an urgent public health problem. Although stabilizing trends in obesity prevalence have been identified in parts of Europe, preventive efforts in children are still needed. Using the socio-ecological approach as the underlying theoretical perspective, the IDEFICS project aimed to develop, implement and evaluate a community-based intervention for the prevention of childhood obesity in eight European countries. The aim of the present manuscript was to describe the content and developmental process of the IDEFICS intervention. Methods: The intervention mapping protocol (IMP) was used to develop the community-based intervention for the prevention of childhood obesity in 3 to 10 years old children. It is a theory-and evidence-based tool for the structured planning and development of health promotion programs that requires the completion of six different steps. These steps were elaborated by two coordinating centers and discussed with the other participating centers until agreement was reached. Focus group research was performed in all participating centers to provide an informed basis for intervention development. Results: The application of the IMP resulted in an overall intervention framework with ten intervention modules targeting environmental and personal factors through the family, the school and the community. The summary results of the focus group research were used to inform the development of the overall intervention. The cultural adaptation of the overall intervention was realised by using country specific focus group results. The need for cultural adaptation was considered during the entire process to improve program adoption and implementation. A plan was developed to evaluate program effectiveness and quality of implementation. Conclusions: The IDEFICS project developed a community-based intervention for the prevention of childhood obesity by using to the intervention mapping heuristic. The IDEFICS intervention consists of a general and standardized intervention framework that allows for cultural adaptation to make the intervention feasible and to enhance deliverability in all participating countries. The present manuscript demonstrates that the development of an intervention is a long process that needs to be done systematically. Time, human resources and finances need to be planned beforehand to make interventions evidence-based and culturally relevant

    The Effectiveness of Sedentary Behaviour Interventions for Reducing Body Mass Index in Children and Adolescents: Systematic Review and Meta-analysis

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    Intervention studies have been undertaken to reduce sedentary behaviour (SB) and thereby potentially ameliorate unhealthy weight gain in children and adolescents. We synthesised evidence and quantified the effects of SB interventions (single or multiple components) on body mass index (BMI) or BMI z-score in this population. Publications up to March 2015 were located through electronic searches. Inclusion criteria were interventions targeting SB in children that had a control group and objective measures of weight and height. Mean change in BMI or BMI z-score from baseline to post-intervention were quantified for intervention and control groups and meta-analyzed using a random effects model. The pooled mean reduction in BMI and BMI z-score was significant but very small (standardized mean difference = -0.060, 95% confidence interval: -0.098 to -0.022). However, the pooled estimate was substantially greater for an overweight or obese population (standardized mean difference = -0.255, 95% confidence interval: -0.400 to -0.109). Multicomponent interventions (SB and other behaviours) delivered to children from 5 to 12 years old in a non-educational setting appear to favour BMI reduction. In summary, SB interventions are associated with very small improvement in BMI in mixed-weight populations. However, SB interventions should be part of multicomponent interventions for treating obese children
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