170 research outputs found
Genetics of attention and executive functioning
Full text linkBoomsma, D.I. [Promotor]Verhulst, F.C. [Promotor]Posthuma, D. [Copromotor
Genetica van aandacht en aandachtsproblemen. Kan executief functioneren dienen als cognitief endofenotype?
No full textThe Genetic Relation between Working Memory Speed and Working Memory Capacity in Children
No full textAttention problems, inhibitory control, and intelligence index overlapping genetic factors: A study in 9, 12 and 18-year-old twins
No full textWhat have we learned from recent twin studies about the etiology of neurodevelopmental disorders?
No full textPurpose of Review: The relative influence of genes and environment on the liability to neurodevelopmental disorders (NDDs) can be investigated using a twin design. This review highlights the results of the most recent twin studies of NDDs. Purpose of Review: Recent twin studies have confirmed that NDDs show moderate-to-high heritability, and that from an etiological viewpoint both autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are best regarded as the extremes on a continuous liability distribution. Both ASD and ADHD show high heritability in childhood and a substantial drop in heritability in adulthood, which is likely explained by the use of different assessment strategies in childhood versus adulthood, or by a complex mechanism of gene-by-environment interaction. NDDs show substantial comorbidity among each other, and with other mental health problems, which is partly because of a shared genetic etiology between different disorders. Summary: The findings of twin studies implicate substantial heritability of NDDs, and warrant large-scale molecular genetic studies for such traits. © 2013 Wolters Kluwer Health | Lippincott Williams & Wilkins
Assessment of Cavitation Erosion with a Multiphase Reynolds-Averaged Navier-Stokes Method
No full textCavitation erosion is one of the remarkable catastrophic consequences of cavitation. Predicting the cavitation aggressiveness quantitatively and predicting the most probable location of cavitation erosion are complex problems that currently still motivate an important amount of basic and applied research in the fields of hydrodynamics, physics and metallurgy. The work addresses two main issues: Numerical simulations of cavitating flows over hydrofoils; and an assessment of the risk of cavitation erosion on the surface of hydrofoils. The capability of the multiphase RANS method to predict the relevant and critical unsteady cavitation dynamics in the flow over hydrofoils has been investigated on two NACA hydrofoils (NACA0015 hydrofoil and NACA0018-45 hydrofoil) in the 2D and 3D domain, respectively. It was found that the large-scale structures and the typical unsteady cavitation dynamics predicted by the RANS method implemented in FLUENT were in fair agreement with the observations from experiments. To find the best criteria for an assessment of the risk of cavitation erosion, current erosion risk assessment models and methodologies that use computational fluid dynamic tools or experimental results as input were reviewed and evaluated. An erosion intensity function was proposed based on the mean value of those values of the time derivative of the local pressure that exceeds a certain threshold, and was evaluated for the NACA0015 hydrofoil and NACA0018-45 hydrofoil. A good correlation was found between the locations with the high erosion risk obtained from the computations and the damage area observed from paint tests.Marine & Transport TechnologyMechanical, Maritime and Materials Engineerin
Erosive aggressiveness of collapsing cavitating structures
No full textThe erosive aggressiveness of idealized cavities collapsing on a flat surface is investigated by numerical simulation, employing the cavitation intensity approach by Leclercq et al (2017) as a measure of the local energy impact rate. We propose a more straight forward formulation of the cavitation intensity model and verify that it satisfies energy conservation requirements for the accumulated surface energy. Based on the cavitation intensity model, statistical aggressiveness indicators are proposed. The indicators account for the rapidness and frequency of the collapse events. The aggressiveness indicators are further applied to a NACA0015 hydrofoil surface.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Ship Hydromechanics and Structure
Pod power and rotation rate rediction
No full textMarine and Transport TechnologyMechanical, Maritime and Materials Engineerin
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