M. Lewkowicz

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

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 coefficient 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 (for the above mentioned filter), below which individuals are at risk.

Geometry of Hamiltonian chaos.

The characterization of chaotic Hamiltonian systems in terms of the curvature associated with a Riemannian metric tensor in the structure of the Hamiltonian is extended to a wide class of potential models of standard form through definition of a conformal metric. The geodesic equations reproduce the Hamilton equations of the original potential model when a transition is made to an associated manifold. We find, in this way, a direct geometrical description of the time development of a Hamiltonian potential model. The second covariant derivative of the geodesic deviation in this associated manifold results in (energy dependent) criteria for unstable behavior different from the usual Lyapunov criteria. We discuss some examples of unstable Hamiltonian systems in two dimensions.

DISCRIMINATION BETWEEN HEALTHY AND SICK CARDIAC AUTONOMIC NERVOUS SYSTEM BY DETRENDED HEART RATE VARIABILITY ANALYSIS

Multiresolution Wavelet Transform and Detrended Fluctuation Analysis have recently been proven to be excellent methods in the analysis of Heart Rate Variability and in distinguishing between healthy subjects and patients with various dysfunctions of the cardiac nervous system. We argue that it is possible to obtain a distinction between healthy subjects/patients of at least similar quality by, first, detrending the time-series of RR-intervals by subtracting a running average based on a local window with a length of around 32 data points, then calculating the standard deviation of the detrended time-series. The results presented here indicate that the analysis can be based on very short time-series of RR-data (7–8 minutes), which is a considerable improvement relative to 24-hour Holter recordings.

Dynamics of particle-hole pair creation in graphene.

The process of coherent creation of particle-hole excitations by an electric field in graphene is quantitatively described. We calculate the evolution of the current density, number of pairs, and energy after switching on the electric field. In particular, it leads to a dynamical visualization of universal finite resistivity without dissipation in pure graphene. We show that the dc conductivity of pure graphene is pi/2e;{2}/h rather than the often cited value of 4/pie;{2}/h. This value coincides with the ac conductivity calculated and measured recently at optical frequencies. The effect of temperature and random chemical potential (charge puddles) are considered and explain the recent experiment on suspended graphene. A possibility of Bloch oscillations is discussed within the tight binding model.

Ballistic transport in graphene beyond linear response

The process of coherent creation of particle-hole excitations by an electric field in graphene is quantitatively described beyond linear response. We calculate the evolution of current density, number of pairs and energy in ballistic regime for electric field

COMPARISON OF RECENT METHODS OF ANALYZING HEART RATE VARIABILITY

E

Chiral Anomaly and Strength of the Electron-Electron Interaction in Graphene

using the tight-binding model. While for ballistic flight times smaller than

Description of complex time series by multipoles

{t}_{nl}\ensuremath{\propto}{E}^{\ensuremath{-}1/2}

Heart Rate Variability Density Analysis (Dyx) and Prediction of Long‐Term Mortality after Acute Myocardial Infarction

current is linear in

Statistical analysis of the DIAMOND MI study by the multipole method

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