Poincare plots are commonly used to study nonlinear behaviour of physiologic signals. Analysis of Poincare plots for various lags can provide interesting insights into the autonomic control of the heart. Furthermore, the width of Poincare plots can be considered as a criterion of short-term variability in heart rate signals. The hypothesis that Poincare plot indexes of heart rate variability (H...

The Lindstedt series were introduced in the XIX century in Astronomy to study perturbatively quasi-periodic motions in Celestial Mechanics. In Mathematical Physics, after getting the attention of Poincaré, who studied them widely by pursuing to all orders the analysis of Lindstedt and Newcomb, their use was somehow superseded by other methods usually referred to as KAM theory. Only recently, af...

Recenzja książki: Iwona Lindstedt, „Piszę tylko muzykę”. Kazimierz Serocki, Kraków 2020. Książka Iwony Lindstedt o Serockim to jedna z najbardziej wartościowych propozycji PWM-u, adresowana do szerokiego odbiorcy. Jest lekturą wymagającą i obszerną, gdyż wymyka się kategorii popularnych dziś wydań kieszonkowych, ocierających niebezpiecznie zarzut „wszystkiego niczego jednocześnie“. Nie uwodzi r...

Heart rate variability (HRV) provides a noninvasive method to monitor functioning of the autonomous nervous system. HRV has been proposed as a potential tool for objective assessment of the level of sedation in critical care. In this paper we studied whether different linear and non-linear analysis methods may discriminate different levels of sedation in cardiac surgery patients. In addition we...

Presently T-wave alternans (TWA) has become a clinical index of non-invasive diagnosis for heart sudden death prediction, and detecting T-wave alternate accurately is particularly important. This paper introduces an algorithm for detecting TWA using Poincare mapping method which is a technique for nonlinear dynamic systems to display periodic behavior. Sample series of beat to beat cycles were ...

We study the possibility of constructing non-BPS charged black holes in 5D Poincare supergravity by partially violating superconformal Killing spinor equations. However, solutions to these modified first order equations are inconsistent with the second order equations of motion beyond the near horizon region. Instead we find, for special prepotentials, that the consistent asymptotically flat ex...

In this paper, we prove that every metric line in the Poincare ball model of hyperbolic geometry is exactly a classical line of itself. We also proved nonexistence of periodic lines in the Poincare ball model of hyperbolic geometry.