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Vereecken C.,Research Foundation Flanders FWO Vlaanderen
Public health nutrition

To evaluate a web-based nutritional knowledge questionnaire for primary-school children. Children's nutritional knowledge was assessed in five domains: healthy choices (twenty-seven items), estimated recommended portions/servings (eight items), nutrient content (five items), main food function (five items) and categorization of food items (eight items). The questionnaires were completed in school. A convenience sample of 576 Belgian children (aged 7-12 years) from fourteen primary schools completed the questionnaire once, 386 completed the questionnaire twice. Healthy choices could be answered correctly by 73 % of the children, nutrients by 59 %, food categorization by 49 %, main function by 38 % and portion estimation by 36 %. Children's test-retest intra-class correlations were 0·75 for healthy choices, 0·33 for nutrients, 0·61 for food categorization, 0·44 for main function, 0·47 for portion estimation and 0·76 for the total scale. The intra-class correlation was lower in the youngest age group (grade 2: 0·51, grade 4: 0·65, grade 6: 0·66). The total score was significantly lower in the retest. The instrument was in general positively evaluated by the children. The instrument is a promising, practical, inexpensive tool with acceptable test-retest reliability in fourth and sixth graders. Source

Vandenbosch L.,Catholic University of Leuven | Vandenbosch L.,Research Foundation Flanders FWO Vlaanderen | Vandenbosch L.,University of Antwerp | Beyens I.,Catholic University of Leuven | And 2 more authors.
European Journal of Pediatrics

Online communication is associated with offline romantic and sexual activity among college students. Yet, it is unknown whether online communication is associated with the initiation of romantic and sexual activity among adolescents. This two-wave panel study investigated whether chatting, visiting dating websites, and visiting erotic contact websites predicted adolescents’ initiation of romantic and sexual activity. We analyzed two-wave panel data from 1163 Belgian adolescents who participated in the MORES Study. We investigated the longitudinal impact of online communication on the initiation of romantic relationships and sexual intercourse using logistic regression analyses. The odds ratios of initiating a romantic relationship among romantically inexperienced adolescents who frequently used chat rooms, dating websites, or erotic contact websites were two to three times larger than those of non-users. Among sexually inexperienced adolescents who frequently used chat rooms, dating websites, or erotic contact websites, the odds ratios of initiating sexual intercourse were two to five times larger than that among non-users, even after a number of other relevant factors were introduced. Conclusion: This is the first study to demonstrate that online communication predicts the initiation of offline sexual and romantic activity as early as adolescence. Practitioners and parents need to consider the role of online communication in adolescents’ developing sexuality.What is Known:• Adolescents increasingly communicate online with peers.• Online communication predicts romantic and sexual activity among college students.What is New:• Online communication predicts adolescents’ offline romantic activity over time.• Online communication predicts adolescents’ offline sexual activity over time. © 2015, Springer-Verlag Berlin Heidelberg. Source

Simoen E.,Interuniversity Microelectronics Center | Mitard J.,Interuniversity Microelectronics Center | De Jaeger B.,Interuniversity Microelectronics Center | Eneman G.,Interuniversity Microelectronics Center | And 10 more authors.
IEEE Transactions on Electron Devices

Low-frequency noise in strained Ge epitaxial layers, which are grown on a reverse-graded relaxed SiGe buffer layer, has been evaluated for different front-end processing conditions. It has been shown that the 1/f noise in strong inversion is governed by trapping in the gate oxide (number fluctuations) and not affected by the presence of compressive strain in the channel. However, some impact has been found from the type of halo implantation used, whereby the lowest noise spectral density and the highest hole mobility are obtained by replacing the standard As halo by P implantation. At the same time, omitting the junction anneal results in poor device characteristics, which can be understood by considering the presence of a high density of nonannealed implantation damage in the channel and the gate stack near the source and the drain. © 2006 IEEE. Source

Vereecken C.A.,Research Foundation Flanders FWO Vlaanderen | Vereecken C.A.,Ghent University | De Bourdeaudhuij I.,Ghent University | Maes L.,Ghent University
European Journal of Clinical Nutrition

Objectives: To investigate the reproducibility of the HELENA Food Frequency Questionnaire (FFQ) developed as a basis for an online tailored intervention and to compare the FFQ with four computerized 24-h recalls. Subjects/methods: A convenience sample of 48 Belgian-Flemish adolescents completed four computerized 24-h recalls, the FFQ and a retest 1-2 weeks later. Correlations, the Wilcoxon's signed rank test and Bland and Altman's plots were used to compare the intakes of 22 food groups, energy (kcal), fibre (g, μg/1000 kcal), vitamin C (mg, mg/1000 kcal), calcium (mg, mg/1000 kcal), iron (mg, mg/1000 kcal) and fat (g, % from total energy).Results: Reproducibility correlations were good (0.46-0.90). De-attenuated correlations between both methods were high (≥0.51) for all nutrients and nutrient densities, except for fibre (g), vitamin C (mg) and percent energy from fat (respectively 0.23, 0.40 and 0.30). On a food group level correlations were significant (r unadjusted >0.3) for most (17/22) food groups. No systematic differences were found between test and retest; comparison with the recalls resulted in a significantly higher intake of bread, breakfast cereals, other snacks, vegetables, potatoes, coffee and tea, alcoholic beverages, energy, and most nutrients. No significant difference was found for calcium, whereas an underestimation was found for nutrient density of calcium and fat. Conclusions: The overestimation in seven food groups, resulting in an overestimation of energy, fibre, iron and vitamin C, and underestimation of percentage energy from fat, needs to be considered when the estimated intakes are used for tailored feedback. © 2010 Macmillan Publishers Limited All rights reserved. Source

Naudts J.,University of Antwerp | Verhulst T.,University of Antwerp | Verhulst T.,Research Foundation Flanders FWO Vlaanderen
Journal of Physics: Conference Series

We introduce the notion of a generalised symmetry M of a hamiltonian H. It is a symmetry which has been broken in a very specific manner, involving ladder operators R and R †. In Theorem 1 these generalised symmetries are characterised in terms of repeated commutators of H with M. Breaking supersymmetry by adding a term linear in the supercharges is discussed as a motivating example. The complex parameter γ which appears in the definition of a generalised symmetry is necessarily real when the spectrum of M is discrete. Theorem 2 shows that γ must also be real when the spectrum of H is fully discrete and R and R † are bounded operators. Any generalised symmetry induces a partitioning of the spectrum of H in what we call M-multiplets. The hydrogen atom in the presence of a symmetry breaking external field is discussed as an example. The notion of stability of eigenvectors of H relative to the generalised symmetry M is discussed. A characterisation of stable eigenvectors is given in Theorem 3. Source

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