Computerized posturography for data analysis and mathematical

Mechanisms of balance control are investigated on computerized posturography data on vertical two-legged and uncomfortable one-legged stance measured on healthy subjects. Oscillations of the centre of mass in the course of 30 s standing and the corresponding trajectories for a step forward off the force platform have been computed. Spectral analysis of the time series revealed three main harmonics for the studied postures. When a volunteer was balancing standing on one leg, all the harmonics were shifted towards the high frequencies and the sway amplitude was twice increased in comparison with comfortable two-legged vertical stance. Decomposition of the sway trajectories into the rambling and trembling components has been carried out. It was shown that in the course of the one-legged stance the balance control strategy includes ‘scanning’ of the larger area with bigger sway amplitudes in the vicinity of the stable state as compared to two-legged stance. A mathematical model of the body as a multi-link system is considered. Mass and inertia of each body segment and torques in joints are taken into consideration. The calculated own and forced frequencies of the model correspond to the spectral analysis of the posturography data. One-legged stance is proposed as an excellent tool for revealing the balance problems. It is shown that investigation of the oscillations and trajectories of the centre of mass for the step forward off the force platform is perspective for medical diagnostics to distinguish between the spine and joint pathologies

Posturographic study of the human body vibrations for clinical diagnos-tics of the spine and joint pathology

Body sway at different stances can be detected in every individual and it is peculiar to normal healthy state. The most accessible and common method of detection of the sway parameters is the measurement of the position of the centre of mass (COM) using the force platform. Com-puterized posturography is widely used as a convenient test for diagnostics of different musculoskeletal, vestibular, nervous, auditory and visual pathology, age-related changes and even the emotional state of the individual. The posturographic data can be used for elaboration novel types and control systems of mobile robots

Computerized posturography for data analysis and mathematical modelling of postural sway during different two-legged and one-legged human stance

Mechanisms of balance control are investigated on computerized posturography data on vertical two-legged and uncomfortable one-legged stance measured on healthy subjects. Oscillations of the centre of mass in the course of 30 s standing and the corresponding trajectories for a step forward off the force platform have been computed. Spectral analysis of the time series revealed three main harmonics for the studied postures. When a volunteer was balancing standing on one leg, all the harmonics were shifted towards the high frequencies and the sway amplitude was twice increased in comparison with comfortable two-legged vertical stance. Decomposition of the sway trajectories into the rambling and trembling components has been carried out. It was shown that in the course of the one-legged stance the balance control strategy includes ‘scanning’ of the larger area with bigger sway amplitudes in the vicinity of the stable state as compared to two-legged stance. A mathematical model of the body as a multi-link system is considered. Mass and inertia of each body segment and torques in joints are taken into consideration. The calculated own and forced frequencies of the model correspond to the spectral analysis of the posturography data. One-legged stance is proposed as an excellent tool for revealing the balance problems. It is shown that investigation of the oscillations and trajectories of the centre of mass for the step forward off the force platform is perspective for medical diagnostics to distinguish between the spine and joint pathologie

Computerized posturography for data analysis and mathematical modelling of postural sway during different two-legged and one-legged human stance

Mechanisms of balance control are investigated on computerized posturography data on vertical two-legged and uncomfortable one-legged stance measured on healthy subjects. Oscillations of the centre of mass in the course of 30 s standing and the corresponding trajectories for a step forward off the force platform have been computed. Spectral analysis of the time series revealed three main harmonics for the studied postures. When a volunteer was balancing standing on one leg, all the harmonics were shifted towards the high frequencies and the sway amplitude was twice increased in comparison with comfortable two-legged vertical stance. Decomposition of the sway trajectories into the rambling and trembling components has been carried out. It was shown that in the course of the one-legged stance the balance control strategy includes ‘scanning’ of the larger area with bigger sway amplitudes in the vicinity of the stable state as compared to two-legged stance. A mathematical model of the body as a multi-link system is considered. Mass and inertia of each body segment and torques in joints are taken into consideration. The calculated own and forced frequencies of the model correspond to the spectral analysis of the posturography data. One-legged stance is proposed as an excellent tool for revealing the balance problems. It is shown that investigation of the oscillations and trajectories of the centre of mass for the step forward off the force platform is perspective for medical diagnostics to distinguish between the spine and joint pathologie

Fixed Volume Effect on Polar Properties and Phase Diagrams of Ferroelectric Semi-ellipsoidal Nanoparticles

For advanced applications in modern industry it is very important to reduce the volume of ferroelectric nanoparticles without serious deterioration of their polar properties. In many practically important cases fixed volume (rather than fixed size) corresponds to realistic technological conditions of nanoparticles fabrication. The letter is focused on the theoretical study of the behavior of ferroelectric polarization, paramagnetoelectric coefficient and phase diagrams of semi-ellipsoidal nanoparticles with fixed volume V. Our approach combines the Landau-Ginzburg-Devonshire phenomenology, classical electrostatics and elasticity theory. Our results show that the size effects of the phase diagrams and polarization of semi-ellipsoidal BiFeO3 nanoparticles nontrivially depends on V. These findings provide a path to optimize the polar properties of nanoparticles by controlling their phase diagrams at a fixed volume.Comment: 15 pages, 5 figures, we added the section IV. Paramagnetoelectric (PME) coefficient at fixed volume in this version and changed title and abstract accordingl

Typology and Factorial Conditioning of Suicidal Behavior of Adolescents

The problem of suicidal behavior of an individual continues to remain relevant, due to the increase in the number of suicides among people of different ages, on the one hand, and insufficient information about the factors of suicidal behavior of an individual. The purpose of the study is to identify the factors that determine the formation of a certain type of personality who committed suicidal attempts in adolescence. In order to identify the types of adolescent suicides, there was conducted a survey of 20 doctors in psychiatric clinical hospitals in Moscow. The survey results were processed using cluster analysis. To identify the factorial conditioning of suicidal behavior of each personality type, a complex of psychodiagnostic techniques was used, focused on the study of the characteristics of the emotional, value-semantic and behavioral spheres of the personality. The obtained empirical data were processed with the help of factor analysis. Three clusters have been identified that combine similar personality characteristics of suicides. It was specified that among adolescents there are the following personality types: “militant” (22%), “sacrifice” (54%) and “self-deprecating” (24%). Each type of adolescent suicide is due to the characteristics of the emotional, value-semantic and behavioral spheres of their personality. To develop targeted programs for the prevention of suicidal behavior among adolescents, it is necessary to take into account the results of the study, since such programs should be aimed at blocking the factors that form a certain type of suicide

Typology and Factorial Conditioning of Suicidal Behavior of Adolescents

The problem of suicidal behavior of an individual continues to remain relevant, due to the increase in the number of suicides among people of different ages, on the one hand, and insufficient information about the factors of suicidal behavior of an individual. The purpose of the study is to identify the factors that determine the formation of a certain type of personality who committed suicidal attempts in adolescence. In order to identify the types of adolescent suicides, there was conducted a survey of 20 doctors in psychiatric clinical hospitals in Moscow. The survey results were processed using cluster analysis. To identify the factorial conditioning of suicidal behavior of each personality type, a complex of psychodiagnostic techniques was used, focused on the study of the characteristics of the emotional, value-semantic and behavioral spheres of the personality. The obtained empirical data were processed with the help of factor analysis. Three clusters have been identified that combine similar personality characteristics of suicides. It was specified that among adolescents there are the following personality types: “militant” (22%), “sacrifice” (54%) and “self-deprecating” (24%). Each type of adolescent suicide is due to the characteristics of the emotional, value-semantic and behavioral spheres of their personality. To develop targeted programs for the prevention of suicidal behavior among adolescents, it is necessary to take into account the results of the study, since such programs should be aimed at blocking the factors that form a certain type of suicide

Typology and Factorial Conditioning of Suicidal Behavior of Adolescents

The problem of suicidal behavior of an individual continues to remain relevant, due to the increase in the number of suicides among people of different ages, on the one hand, and insufficient information about the factors of suicidal behavior of an individual. The purpose of the study is to identify the factors that determine the formation of a certain type of personality who committed suicidal attempts in adolescence. In order to identify the types of adolescent suicides, there was conducted a survey of 20 doctors in psychiatric clinical hospitals in Moscow. The survey results were processed using cluster analysis. To identify the factorial conditioning of suicidal behavior of each personality type, a complex of psychodiagnostic techniques was used, focused on the study of the characteristics of the emotional, value-semantic and behavioral spheres of the personality. The obtained empirical data were processed with the help of factor analysis. Three clusters have been identified that combine similar personality characteristics of suicides. It was specified that among adolescents there are the following personality types: “militant” (22%), “sacrifice” (54%) and “self-deprecating” (24%). Each type of adolescent suicide is due to the characteristics of the emotional, value-semantic and behavioral spheres of their personality. To develop targeted programs for the prevention of suicidal behavior among adolescents, it is necessary to take into account the results of the study, since such programs should be aimed at blocking the factors that form a certain type of suicide

Mesoscopic theory of defect ordering-disordering transitions in thin oxide films

Ordering of mobile defects in functional materials can give rise to fundamentally new phases possessing ferroic and multiferroic functionalities. Here we develop the Landau theory for strain induced ordering of defects (e.g. oxygen vacancies) in thin oxide films, considering both the ordering and wavelength of possible instabilities. Using derived analytical expressions for the energies of various defect-ordered states, we calculated and analyzed phase diagrams dependence on the film-substrate mismatch strain, concentration of defects, and Vegard coefficients. Obtained results open possibilities to create and control superstructures of ordered defects in thin oxide films by selecting the appropriate substrate and defect concentration.Comment: 30 pages, 5 figures, 1 appendi