Self-dual SU(2) invariant Einstein metrics and modular dependence of theta-functions

We simplify Hitchin's description of SU(2)-invariant self-dual Einstein metrics, making use of the tau-function of related four-pole Schlesinger system.Comment: A wrong sign in the formula for W_1 is corrected; we thank Owen Dearricott who pointed out this mistake in the original version of the pape

Two-band superconductors: Extended Ginzburg-Landau formalism by a systematic expansion in small deviation from the critical temperature

We derive the extended Ginzburg-Landau (GL) formalism for a clean s-wave two-band superconductor by employing a systematic expansion of the free-energy functional and the corresponding matrix gap equation in powers of the small deviation from the critical temperature tau = 1-T/T_c. The two lowest orders of this expansion produce the equation for T_c and the GL theory. It is shown that in agreement with previous studies, the two-band GL theory maps onto the single-band GL model and thus fails to describe the difference in the spatial profiles of the two band condensates. We prove that except for some very special cases, this difference appears already in the leading correction to the GL theory, which constitutes the extended GL formalism. We derive linear differential equations that determine the leading corrections to the band order parameters and magnetic field, discuss the validity of these equations, and consider examples of an important interplay between the band condensates. Finally, we present numerical results for the thermodynamic critical magnetic field and temperature-dependent band gaps (at zero field), which are in a very good agreement with those obtained from the full BCS approach in a wide temperature range. To this end, we emphasize the advantages of our extended GL theory in comparison with the often used two-component GL-like model based on an unreconstructed two-band generalization of the Gor'kov derivation

Mobile Hardware-Information System for Neuro-Electrostimulation

The article describes organizational principles of the mobile hardware-informational system based on the multifactorial neuro-electrostimulation device. The system is implemented with two blocks: the first block forms the spatially distributed field of low-frequency monopolar current pulses between two multielement electrodes in the neck region. Functions of the second block, specialized control interface, are performed by a smartphone. Information is exchanged between two blocks through a telemetric channel. The mobile hardware-informational system allows to remotely change the structure of the current pulses field, to control its biotropic characteristics and to change the targets of the stimulation. Moreover, it provides patient data collection and processing, as well as access to the specialized databases. The basic circuit solutions for the neuro-electrostimulation device, implemented by means of microcontroller and elements of high-level hardware integration, are described. The prospects of artificial intelligence and machine learning application for treatment process management are discussed. © 2018 Vladimir S. Kublanov et al.)is study was supported by the Act 211 of the Government of the Russian Federation (contract no. 02.A03.21.0006) and was funded by RFBR (project no, 18-29-02052)

Regularities of Changes in Structure and Texture of Low Modulus Alloy Zr-25Nb at Cold Rolling of Monocrystals with Different Orientations

The paper presents the results of studying the regularities of formation of the rolling texture in single crystals of Zr-25%Nb alloy, with different initial orientation relative to the external principal directions in the sheet: normal (ND) and rolling direction (RD). Varying the initial orientation of the single crystal made it possible to reveal stable orientations, among which are textural components {001} <100>, {001} <110>, {111} <110> and {111} <112>. For orientation <111> of single crystal, in the matrix of a quasi-single crystal it was possible to detect a finely dispersed ω-phase, which causes the appearance of an extended halo in the diffraction spectrum. The presence o

Physical degrees of freedom in stabilized brane world models

We consider brane world models with interbrane separation stabilized by the Goldberger-Wise scalar field. For arbitrary background, or vacuum configurations of the gravitational and scalar fields in such models, we construct the second variation Lagrangian, study its gauge invariance, find the corresponding equations of motion and decouple them in a suitable gauge. We also derive an effective four-dimensional Lagrangian for such models, which describes the massless graviton, a tower of massive gravitons and a tower of massive scalars. It is shown that for a special choice of the background solution the masses of the graviton excitations may be of the order of a few TeV, the radion mass of the order of 100 GeV, the inverse size of the extra dimension being tens of GeV. In this case the coupling of the radion to matter on the negative tension brane is approximately the same as in the unstabilized model with the same values of the fundamental five-dimensional energy scale and the interbrane distance.Comment: 17 pages, LaTeX, corrected typos, amended the normalization constants of the scalar modes and their coupling constants to matte

Principles of organization and control of the new implementation of the “SYMPATHOCOR-01” neuro-electrostimulation device

The paper describes peculiarities of the organizational and control principles of the new implementation of the “SYMPATHOCOR-01” device. Necessity of the device division into two blocks, having different functions, was justified. The specifics of the schematic implementation were mentioned. Advantages of the wireless connection between two blocks were shown. Particular possibilities and actual implementation of the control block via Android application for mobile devices were presented. The potential targets for the neuro-electrostimulation that affect autonomic processes were considered. Copyright © 2017 by SCITEPRESS – Science and Technology Publications, Lda. All rights reserved

On some possibilities of organizing a mobile hardware-information system for polyfactorial neuro-electrostimulation

In paper the organizational principles of the mobile hardware-information system for polyfactorial neuroelectrostimulation were considered. It was shown that the system can be implemented by three functionally separate blocks, one of which ensures the formation of a spatially distributed field of current pulses, the second is the specialized interface for the patient, and the third is the specialized interface for the doctor. The exchange of information between the blocks is provided by a telemetric communication channel or via the global network using mobile wearable computers (which can include a personal computer, tablet or smartphone). A personalized patient information system can be implemented on the basis of the neuroelectrostimulation system. In this case patient data can be placed on the server of the medical institution. The prospects for using artificial intelligence and machine learning to control the treatment process were discussed. © 2019 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved

Regular modes in rotating stars

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray dynamics to build an asymptotic theory for the subset of regular modes which are the easiest to observe and identify. Comparisons with 2D numerical simulations of oscillations in polytropic stars show that both the frequency and amplitude distributions of these modes can accurately be described by an asymptotic theory for almost all rotation rates. The spectra are mainly characterized by two quantum numbers; their extraction from observed spectra should enable one to obtain information about stellar interiors.Comment: 5 pages, 4 figures, discussion adde

Quaternionic factorization of the Schroedinger operator and its applications to some first order systems of mathematical physics

We consider the following first order systems of mathematical physics. 1.The Dirac equation with scalar potential. 2.The Dirac equation with electric potential. 3.The Dirac equation with pseudoscalar potential. 4.The system describing non-linear force free magnetic fields or Beltrami fields with nonconstant proportionality factor. 5.The Maxwell equations for slowly changing media. 6.The static Maxwell system. We show that all this variety of first order systems reduces to a single quaternionic equation the analysis of which in its turn reduces to the solution of a Schroedinger equation with biquaternionic potential. In some important situations the biquaternionic potential can be diagonalized and converted into scalar potentials