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- Cuenca-Garcia, Magdalena, et al.
(författare)
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More Physically Active and Leaner Adolescents Have Higher Energy Intake
- 2014
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Ingår i: The Journal of Pediatrics. - : Elsevier BV. - 0022-3476 .- 1097-6833. ; 164:1, s. 159-166
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Tidskriftsartikel (refereegranskat)abstract
- Objective To test whether youths who engage in vigorous physical activity are more likely to have lean bodies while ingesting relatively large amounts of energy. For this purpose, we studied the associations of both physical activity and adiposity with energy intake in adolescents.Study design The study subjects were adolescents who participated in 1 of 2 cross-sectional studies, the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study (n = 1450; mean age, 14.6 years) or the European Youth Heart Study (EYHS; n = 321; mean age, 15.6 years). Physical activity was measured by accelerometry, and energy intake was measured by 24-hour recall. In the HELENA study, body composition was assessed by 2 or more of the following methods: skinfold thickness, bioelectrical impedance analysis, plus dual-energy X-ray absorptiometry or air-displacement plethysmography in a subsample. In the EYHS, body composition was assessed by skinfold thickness.Results Fat mass was inversely associated with energy intake in both studies and using 4 different measurement methods (P <=.006). Overall, fat-free mass was positively associated with energy intake in both studies, yet the results were not consistent across measurement methods in the HELENA study. Vigorous physical activity in the HELENA study (P<.05) and moderate physical activity in the EYHS (P<.01) were positively associated with energy intake. Overall, results remained unchanged after adjustment for potential confounding factors, after mutual adjustment among the main exposures (physical activity and fat mass), and after the elimination of obese subjects, who might tend to under-report energy intake, from the analyses.Conclusion Our data are consistent with the hypothesis that more physically active and leaner adolescents have higher energy intake than less active adolescents with larger amounts of fat mass.
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| 2. |
- Faure, B., et al.
(författare)
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2D to 3D crossover of the magnetic properties in ordered arrays of iron oxide nanocrystals
- 2013
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 5:3, s. 953-960
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Tidskriftsartikel (refereegranskat)abstract
- The magnetic 2D to 3D crossover behavior of well-ordered arrays of monodomain γ-Fe2O3 spherical nanoparticles with different thicknesses has been investigated by magnetometry and Monte Carlo (MC) simulations. Using the structural information of the arrays obtained from grazing incidence small-angle X-ray scattering and scanning electron microscopy together with the experimentally determined values for the saturation magnetization and magnetic anisotropy of the nanoparticles, we show that MC simulations can reproduce the thickness-dependent magnetic behavior. The magnetic dipolar particle interactions induce a ferromagnetic coupling that increases in strength with decreasing thickness of the array. The 2D to 3D transition in the magnetic properties is mainly driven by a change in the orientation of the magnetic vortex states with increasing thickness, becoming more isotropic as the thickness of the array increases. Magnetic anisotropy prevents long-range ferromagnetic order from being established at low temperature and the nanoparticle magnetic moments instead freeze along directions defined by the distribution of easy magnetization directions.
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| 3. |
- Ortega, Francisco B., et al.
(författare)
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Cardiovascular fitness modifies the associations between physical activity and abdominal adiposity in children and adolescents : The European Youth Heart Study
- 2010
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Ingår i: British Journal of Sports Medicine. - London, United Kingdom : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 44:4, s. 256-262
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To examine the associations between physical activity (PA) and abdominal adiposity, as measured by waist circumference, in children and adolescents, and to test whether cardiovascular fitness (CVF) modifies these associations.Methods: PA components were measured by accelerometry in 1075 individuals aged 9 or 15 years old. CVF was measured by a maximal cycling test. Self-reported maternal educational level, body mass index, children's birth weight and television viewing were used as confounders.Results: Linear regression did not show any association between the PA variables and waist circumference, after controlling for sex, age and height. When stratifying by CVF level (low/high), time spent at vigorous PA was inversely associated with waist circumference (p≤0.05) in the low CVF group. Unexpectedly, in the high CVF group, the PA variables were positively associated with waist circumference (p≤0.05). In both groups, the results were unchanged after controlling for the confounders. CVF was inversely associated with waist circumference, after controlling for all PA variables (p≤0.01) and confounders (p≤0.01).Conclusion: CVF is inversely associated with abdominal adiposity and seems to modify the associations between PA and abdominal adiposity. In low-fit children and adolescents, time spent in vigorous PA seems to be the key component linked to abdominal adiposity. This finding should be considered in further development of lifestyle intervention strategies. The results found in the high-fit group need to be confirmed.
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