422 research outputs found

    Chrono-Nutrition: The Relationship between Time-of-Day Energy and Macronutrient Intake and Children's Body Weight Status

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    The time of eating has been considered to have an important role in weight regulation. However, it is unknown if there are specific daily patterns of energy and macronutrient distribution that could be more beneficial for metabolic outcomes, especially obesity. This study aimed to assess the effect of time-of-day energy and macronutrient intake at 4 y of age on the weight status at 7 y of age. The study sample included 1961 children from the population-based birth cohort Generation XXI, with data on 3-day food diaries at 4 y and body mass index (BMI) z-scores at 7 y. Dietary patterns based on the collected data were obtained for the distribution of energy and macronutrients across eating occasions. Having a relatively higher energy intake at lunch and supper (OR = 1.19, 95% CI = 1.05 to 1.34) or at mid-afternoon (OR = 1.18, 95% CI = 1.05 to 1.34) at 4 y was associated with higher odds of becoming overweight/obese at 7 y. A relatively higher intake of fat at lunch was positively associated with later children’s odds for being overweight or obese (OR = 1.17, 95% CI = 1.03 to 1.32). These associations were independent of the effect on children’s eating behaviors related to appetite. Our results also show a detrimental relation between skipping breakfast and eating late in the day and children’s body weight. Considering all daily eating occasions, a higher proportion of energy and macronutrient intake at the main meals and a lower proportion during the afternoon and evening seems to be more beneficial for children’s weight. These results emphasize the important role of daily food intake rhythm on excessive weight gain in childhood

    Demanda hídrica e eficiência de uso da água pelo arroz: influência do período de supressão da irrigação.

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    Development and validation of predictive equations for spirometry in Portuguese children

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    Background There are no data on lung function reference values for Portuguese children, and the contribution from the Portuguese data set in the Global Lung Function Initiative (GLI) is scant. Objectives We aimed to estimate new up-to-date reference values for Portuguese children by fitting a multivariable regression model to a general population sample. Further, we intended to assess the external validity of the obtained reference values and to compare them to the GLI reference values. Methods A random sample of 858 children from 20 primary schools were screened by health questionnaire, physical examination, and spirometry. Spirometric parameters recorded were FVC, FEV1, and FEF25-75. Multiple regression models were used to derive reference equations. Results Overall, 481 children, aged between 7 and 12 years, 267 boys (55.5%), were included. Boys had higher values for FVC and FEV1 than girls (P < .05). The strongest correlation was found for FVC with height (r = 0.71 for boys and 0.70 for girls), while the lowest correlation was observed in both sexes for FEF25-75 with age (r = 0.23). Height was the most significant predictor of FVC, FEV1, and FEF25-75 in our models. Weight and body mass index were not significant predictors for boys but had a significant effect on girls’ equations for all spirometry parameters. Compared to obtained reference equations with GLI, they performed better for FVC in boys, FEV1 in girls, and FEF25-75 in both boys and girls. Conclusion We offer up-to-date reference values of spirometry for Portuguese children that can be used in clinical practice and research.Deriving cohort was funded by Project NORTE-01-0145-FEDER-000010 – Health, Comfort and Energy in the Built Environment (HEBE), cofinanced by Programa Operacional Regional do Norte (NORTE2020), through Fundo Europeu de Desenvolvimento Regional (FEDER and of the Foundation for Science and Technology schoolarships SFRH/BD/108605/2015 and SFRH/BD/112269/2015. Validating cohort was funded by Programa Operacional de Saúde – Saúde XXI, Quadro Comunitário de Apoio III and by Administração Regional de Saúde do Norte. For follow-up assessments Generation XXI received funding from Fundação para a Ciência e a Tecnologia (PTDC/SAU-ESA/108577/ 2008), co-funded by FEDER through COMPETE and from Fundação Calouste Gulbenkian. This work was supported by national funds through FCT – Fundação para a Ciência e Tecnologia, I.P., under the projects 2022.07363.PTDC, UIDB/04750/2020 and LA/P/0064/2020. Generation XXI was funded by Programa Operacional de Saúde – Saúde XXI, Quadro Comunitário de Apoio III and Administração Regional de Saúde Norte (Regional Department of Ministry of Health)

    Application of a Latent Transition Model to Estimate the Usual Prevalence of Dietary Patterns

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    Background: This study aims to derive habitual dietary patterns of the Portuguese adult population by applying two methodological approaches: a latent class model and a latent transition model. The novel application of the latent transition model allows us to determine the day-to-day variability of diet and to calculate the usual prevalence of dietary patterns. Methods: Participants are from the National Food, Nutrition and Physical Activity Survey of the Portuguese population, 2015-2016 (2029 women; 1820 men, aged >= 18 years). Diet was collected by two 24 h dietary recalls (8-15 days apart). Dietary patterns were derived by: (1) a latent class model using the arithmetic mean of food weigh intake, with concomitant variables (age and sex); (2) a latent transition model allowing the transition from one pattern to another, with the same concomitant variables. Results: Six dietary patterns were identified by a latent class model. By using a latent transition model, three dietary patterns were identified: "In-transition to Western" (higher red meat and alcohol intake; followed by middle-aged men), "Western" (higher meats/eggs and energy-dense foods intake; followed by younger men), and "Traditional-Healthier" (higher intake of fruit, vegetables and fish, characteristic of older women). Most individuals followed the same pattern on both days, but around 26% transited between "In-transition to Western" and "Western". The prevalence of the dietary patterns using a single recall day (40%, 27%, 33%, respectively) is different from the usual prevalence obtained by the latent transition probabilities (48%, 36%, 16%). Conclusion: Three dietary patterns, largely dependent on age and sex, were identified for the Portuguese adult population: "In-transition to Western" (48%), "Western" (36%), and "Traditional-Healthier" (16%), but 26% were transient between patterns. Dietary patterns are, in general, deviating from traditional habits

    Scaling of spontaneous rotation with temperature and plasma current in tokamaks

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    Using theoretical arguments, a simple scaling law for the size of the intrinsic rotation observed in tokamaks in the absence of momentum injection is found: the velocity generated in the core of a tokamak must be proportional to the ion temperature difference in the core divided by the plasma current, independent of the size of the device. The constant of proportionality is of the order of 10kms1MAkeV110\,\mathrm{km \cdot s^{-1} \cdot MA \cdot keV^{-1}}. When the intrinsic rotation profile is hollow, i.e. it is counter-current in the core of the tokamak and co-current in the edge, the scaling law presented in this Letter fits the data remarkably well for several tokamaks of vastly different size and heated by different mechanisms.Comment: 5 pages, 3 figure
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