BIOELECTRIC ACTIVITY OF THE BRAIN IN PUPILS WITH DIFFERENT ACADEMIC SUCCESS. REPORT 2. THE RELATIONSHIP BETWEEN THE ACADEMIC SUCCESS AND PATTERNS OF BIOELECTRIC ACTIVITY OF THE CORTEX

Background. The paper presents the study of the factors of academic success and failure in students, which is a relevant and socially significant problem. Academic failure often results in behavior deviations, drug abuse and other types of dangerous behavior. Therefore, it is of utmost importance to establish the reasons of academic failure, as well as the ways to improve academic performance. Aim. The paper aims to establish the features of responses of academically successful and unsuccessful 12-year-old children to cognitive load based on EEG data. Materials and methods. Twelve-year-old schoolchildren (n = 51) from Ekaterinburg participated in the study. Participants were divided into two groups depending on their academic performance. EEG recording was performed using the CONAN-m equipment (Informatics and Computers, Russia). Monopolar EEG recordings were obtained from 10 symmetrical leads in different conditions: during resting wakefulness (for eyes open and closed) and when solving experimental tasks of three types (simple arithmetic task, verbal and logical task, spatial thinking task). The differences between the samples of academically successful and unsuccessful children were assessed using the Wilcoxon nonparametric test. Results. Differences were revealed in a number of EEG indicators both at rest and when solving experimental tasks between academically successful and unsuccessful schoolchildren. The responses of academically successful children to cognitive load were characterized by predominant ctivation of the anterior cortical areas with a focus of activity in the left frontal area. Academically unsuccessful children were characterized by a more generalized type of EEG response with a focus of activity in the caudal areas of the cortex, especially when solving a figure rotation task. It was also found that successful children made mistakes when solving a figure rotation task and unsuccessful ones-when solving verbal and logical tasks. Conclusion. Children with low academic success were found to have characteristic features of the functioning of the cerebral cortex, which hampered the perception of educational material presented in the form of a logically structured message. However, these children were able to brilliantly operate with visual-spatial information. This must be taken into account when working with such children to improve their academic performance.

R fluids

A theory of collisionless fluids is developed in a unified picture, where nonrotating (?f1 = ?f2 = ?f3 = 0) figures with some given random velocity component distributions, and rotating (?f1 = ?f2 = ?f3 ) figures with a different random velocity component distributions, make adjoint configurations to the same system. R fluids are defined as ideal, self-gravitating fluids satisfying the virial theorem assumptions, in presence of systematic rotation around each of the principal axes of inertia. To this aim, mean and rms angular velocities and mean and rms tangential velocity components are expressed, by weighting on the moment of inertia and the mass, respectively. The figure rotation is defined as the mean angular velocity, weighted on the moment of inertia, with respect to a selected axis. The generalized tensor virial equations (Caimmi and Marmo 2005) are formulated for R fluids and further attention is devoted to axisymmetric configurations where, for selected coordinate axes, a variation in figure rotation has to be counterbalanced by a variation in anisotropy excess and vice versa. A microscopical analysis of systematic and random motions is performed under a few general hypotheses, by reversing the sign of tangential or axial velocity components of an assigned fraction of particles, leaving the distribution function and other parameters unchanged (Meza 2002). The application of the reversion process to tangential velocity components is found to imply the conversion of random motion rotation kinetic energy into systematic motion rotation kinetic energy. The application of the reversion process to axial velocity components is found to imply the conversion of random motion translation kinetic energy into systematic motion translation kinetic energy, and the loss related to a change of reference frame is expressed in terms of systematic motion (imaginary) rotation kinetic energy. A number of special situations are investigated in greater detail. It is found that an R fluid always admits an adjoint configuration where figure rotation occurs around only one principal axis of inertia (R3 fluid), which implies that all the results related to R3 fluids (Caimmi 2007) may be ex- tended to R fluids. Finally, a procedure is sketched for deriving the spin parameter distribution (including imaginary rotation) from a sample of observed or simulated large-scale collisionless fluids i.e. galaxies and galaxy clusters.

Figure Rotation of Dark Halos in Cold Dark Matter Simulations

We investigate the rotation of dark matter halos identified in ΛCDM simulations. After removing halos that contain a significant amount of substructure, about 82% of the remaining halos were found to undergo coherent rotation over 5h−1 Gyr. The rotation speeds follow a log-normal distribution. The average rotation speed of a halo was 0.11h rads/Gyr. Less than half of the selected halos showed alignment between their rotation and minor axes. We found no correlation between halo properties, such as total mass, and the rotation speed.