1,326 research outputs found

    Discrimination of the Healthy and Sick Cardiac Autonomic Nervous System by a New Wavelet Analysis of Heartbeat Intervals

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    We demonstrate that it is possible to distinguish with a complete certainty between healthy subjects and patients with various dysfunctions of the cardiac nervous system by way of multiresolutional wavelet transform of RR intervals. We repeated the study of Thurner et al on different ensemble of subjects. We show that reconstructed series using a filter which discards wavelet coefficients related with higher scales enables one to classify individuals for which the method otherwise is inconclusive. We suggest a delimiting diagnostic value of the standard deviation of the filtered, reconstructed RR interval time series in the range of 0.035\sim 0.035 (for the above mentioned filter), below which individuals are at risk.Comment: 5 latex pages (including 6 figures). Accepted in Fractal

    Inverse eigenvalue problem for discrete three-diagonal Sturm-Liouville operator and the continuum limit

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    In present article the self-contained derivation of eigenvalue inverse problem results is given by using a discrete approximation of the Schroedinger operator on a bounded interval as a finite three-diagonal symmetric Jacobi matrix. This derivation is more correct in comparison with previous works which used only single-diagonal matrix. It is demonstrated that inverse problem procedure is nothing else than well known Gram-Schmidt orthonormalization in Euclidean space for special vectors numbered by the space coordinate index. All the results of usual inverse problem with continuous coordinate are reobtained by employing a limiting procedure, including the Goursat problem -- equation in partial derivatives for the solutions of the inversion integral equation.Comment: 19 pages There were made some additions (and reformulations) to the text making the derivation of the results more precise and understandabl

    Inverse Spectral-Scattering Problem with Two Sets of Discrete Spectra for the Radial Schroedinger Equation

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    The Schroedinger equation on the half line is considered with a real-valued, integrable potential having a finite first moment. It is shown that the potential and the boundary conditions are uniquely determined by the data containing the discrete eigenvalues for a boundary condition at the origin, the continuous part of the spectral measure for that boundary condition, and a subset of the discrete eigenvalues for a different boundary condition. This result extends the celebrated two-spectrum uniqueness theorem of Borg and Marchenko to the case where there is also a continuous spectru

    Application of approximation theory by nonlinear manifolds in Sturm-Liouville inverse problems

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    We give here some negative results in Sturm-Liouville inverse theory, meaning that we cannot approach any of the potentials with m+1m+1 integrable derivatives on R+\mathbb{R}^+ by an ω\omega-parametric analytic family better than order of (ωlnω)(m+1)(\omega\ln\omega)^{-(m+1)}. Next, we prove an estimation of the eigenvalues and characteristic values of a Sturm-Liouville operator and some properties of the solution of a certain integral equation. This allows us to deduce from [Henkin-Novikova] some positive results about the best reconstruction formula by giving an almost optimal formula of order of ωm\omega^{-m}.Comment: 40 page

    Development of teacher’s language personality in the modern information and educational environment of the university

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    Цель: исследовать структуру и содержание развития языковой личности педагога и выявить субъективные и средовые факторы, влияющие на полноту самореализации его личностного потенциала в профессиональной деятельности и общении. Методология: используются когнитивно-дискурсивный и синергетический методы. Выводы: Повышение эффективности и качества иноязычного профессионального образования в решающей степени зависит от сформированности триединой основы образовательного процесса: компетентная личность преподавателя – эффективный современный учебник – мотивированный на учебу студент.The aim of the article is to examine the structure and content of the teacher’s language personality development and to identify subjective and environmental factors affecting the completeness of personal potential self-realization in professional activity and communication. Methodology: cognitive-discursive and synergetic methods are used. Conclusions: Improving the efficiency and quality of foreign language professional education depends crucially on the formation of the triune basis of the educational process: a competent teacher's personality – an effective modern textbook - a student motivated to study

    Primordial pairing and binding of superheavy charge particles in the early Universe

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    Primordial superheavy particles, considered as the source of Ultra High Energy Cosmic Rays (UHECR) and produced in local processes in the early Universe, should bear some strictly or approximately conserved charge to be sufficiently stable to survive to the present time. Charge conservation makes them to be produced in pairs, and the estimated separation of particle and antiparticle in such pair is shown to be in some cases much smaller than the average separation determined by the averaged number density of considered particles. If the new U(1) charge is the source of a long range field similar to electromagnetic field, the particle and antiparticle, possessing that charge, can form primordial bound system with annihilation timescale, which can satisfy the conditions, assumed for this type of UHECR sources. These conditions severely constrain the possible properties of considered particles.Comment: Latex, 4 pages. The final version to appear in Pis'ma ZhETF (the conditions for the primordial binding are specified, some refs added

    Stability of the inverse resonance problem on the line

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    In the absence of a half-bound state, a compactly supported potential of a Schr\"odinger operator on the line is determined up to a translation by the zeros and poles of the meropmorphically continued left (or right) reflection coefficient. The poles are the eigenvalues and resonances, while the zeros also are physically relevant. We prove that all compactly supported potentials (without half-bound states) that have reflection coefficients whose zeros and poles are \eps-close in some disk centered at the origin are also close (in a suitable sense). In addition, we prove stability of small perturbations of the zero potential (which has a half-bound state) from only the eigenvalues and resonances of the perturbation.Comment: 21 page

    Reconstruction of the optical potential from scattering data

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    We propose a method for reconstruction of the optical potential from scattering data. The algorithm is a two-step procedure. In the first step the real part of the potential is determined analytically via solution of the Marchenko equation. At this point we use a diagonal Pad\'{e} approximant of the corresponding unitary SS-matrix. In the second step the imaginary part of the potential is determined via the phase equation of the variable phase approach. We assume that the real and the imaginary parts of the optical potential are proportional. We use the phase equation to calculate the proportionality coefficient. A numerical algorithm is developed for a single and for coupled partial waves. The developed procedure is applied to analysis of 1S0^{1}S_{0} NNNN, 3SD1^{3}SD_{1} NNNN, P31P31 πN\pi^{-} N and S01S01 K+NK^{+}N data.Comment: 26 pages, 8 figures, results of nucl-th/0410092 are refined, some new results are presente
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