National Research University – Higher School of Economics

About: National Research University – Higher School of Economics is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Population & Computer science. The organization has 12873 authors who have published 23376 publications receiving 256396 citations.

"N"-Back Working Memory Task: Meta-Analysis of Normative fMRI Studies with Children.

Abstract: The n-back task is likely the most popular measure of working memory for functional magnetic resonance imaging (fMRI) studies. Despite accumulating neuroimaging studies with the n-back task and children, its neural representation is still unclear. fMRI studies that used the n-back were compiled, and data from children up to 15 years (n = 260) were analyzed using activation likelihood estimation. Results show concordance in frontoparietal regions recognized for their role in working memory as well as regions not typically highlighted as part of the working memory network, such as the insula. Findings are discussed in terms of developmental methodology and potential contribution to developmental theories of cognition. [ABSTRACT FROM AUTHOR]

Brascamp–Lieb-Type Inequalities on Weighted Riemannian Manifolds with Boundary

Abstract: It is known that by dualizing the Bochner–Lichnerowicz–Weitzenbock formula, one obtains Poincare-type inequalities on Riemannian manifolds equipped with a density, which satisfy the Bakry–Emery Curvature-Dimension condition (combining a lower bound on its generalized Ricci curvature and an upper bound on its generalized dimension). When the manifold has a boundary, an appropriate generalization of the Reilly formula may be used instead. By systematically dualizing this formula for various combinations of boundary conditions of the domain (convex, mean-convex) and the function (Neumann, Dirichlet), we obtain new Brascamp–Lieb-type inequalities on the manifold. All previously known inequalities of Lichnerowicz, Brascamp–Lieb, Bobkov–Ledoux, and Veysseire are recovered, extended to the Riemannian setting and generalized into a single unified formulation, and their appropriate versions in the presence of a boundary are obtained. Our framework allows to encompass the entire class of Borell’s convex measures, including heavy-tailed measures, and extends the latter class to weighted-manifolds having negative generalized dimension.

Interaction of a large amplitude interfacial solitary wave of depression with a bottom step

Abstract: This paper is devoted to the study of the transformation of a finite-amplitude interfacial solitary wave of depression at a bottom step. The parameter range studied goes outside the range of weakly nonlinear theory (the extended Korteweg–de Vries or Gardner equation), and we describe various scenarios of this transformation in terms of the incident wave amplitude and the step height. The dynamics and energy balance of the transformation are described. Several numerical simulations are carried out using the nonhydrostatic model based on the fully nonlinear Navier–Stokes equations in the Boussinesq approximation. Three distinct runs are discussed in detail. The first simulation is done when the ratio of the step height to the lower layer thickness after the step is about 0.4 and the incident wave amplitude is less than the limiting value estimated for a Gardner solitary wave. It shows the applicability of the weakly nonlinear model to describe the transformation of a strongly nonlinear wave in this case. In the second simulation, the ratio of the step height to the lower layer thickness is the same as that in the first run but the incident wave amplitude is increased and then its shape is described by the Miyata–Choi–Camassa solitary wave solution. In this case, the process of wave transformation is accompanied by shear instability and the billows that result in a thickening of the interface layer. In the third simulation, the ratio of the step height to the thickness of the lower layer after the step is 1.33, and then the same Miyata–Choi–Camassa solitary wave passes over the step, it undergoes stronger reflection and mixing between the layers although Kelvin–Helmholtz instability is absent. The energy budget of the wave transformation is calculated. It is shown that the energy loss in the vicinity of the step grows with an increase of the ratio of the incident wave amplitude to the thickness of the lower layer over the step.