An investigation of the nonlinear dynamics of a heart model is presented. The model compartmentalizes the heart into one part that beats autonomously (the x oscillator), representing the pacemaker or SA node, and a second part that beats only if excited by a signal originating outside itself (the y oscillator), representing typical cardiac tissue. Both oscillators are modeled by piecewise linea...

 In this work, time domain analysis is used to solve Adler’s equation in order to obtain the required time, for an oscillator under external injection, reaching the steady-state condition. Mathematical approach has been applied to fully describe the transient of frequency acquisition in injection-locked LC and Ring oscillators considering their time-varying nature. Then, the analysis is verifie...

Constraints on the possible shape and clustering , as well as optical properties, of grains responsible for the 2175Å interstellar extinction feature (interstel-lar UV bump) are discussed. These constraints are based on the observation that the peak position of the inter-stellar UV feature is very stable (variations < ∼ 1%), that the large variations in width (< ∼ 25%) are uncorrelated with the...

Almost all organisms show some kind of time periodicity in their behavior. Especially in mammals the neurons of the suprachiasmatic nucleus form a biological clock regulating the activity-inactivity cycle of the animal. This clock is stimulated by the natural 24-hour light-dark cycle. In our model of this system we consider each neuron as a so called phase oscillator, coupled to other neurons f...

The one-dimensional harmonic oscillator in a box problem is used to introduce the concept of an oblique-basis shell-model theory. The method is applied to nuclei by combining traditional spherical shell-model states with SU(3) collective configurations. An application to Mg, using the realistic two-body interaction of Wildenthal, is used to explore the validity of this oblique-basis, mixed-symm...

A room-temperature mechanical oscillator undergoes thermal Brownian motion with an amplitude much larger than the associated a single phonon of excitation. This can be read out and manipulated using laser light cavity-optomechanical approach. By performing strong quantum measurement (i.e., counting photons in sidebands imparted on laser), we herald addition subtraction phonons 300 K motional st...

Bioluminescence techniques allow accurate monitoring of the circadian clock in single cells. We have analyzed bioluminescence data of Per gene expression in mouse SCN neurons and fibroblasts. From these data, we extracted parameters such as damping rate and noise intensity using two simple mathematical models, one describing a damped oscillator driven by noise, and one describing a self-sustain...

The literature on quantum mechanics in a finite-dimensional Hilbert space is substantial. This paper is devoted to an algebraic model for a quantum oscillator allowing finite-dimensional representations, thus leading to a finite oscillator model. The canonical one-dimensional quantum oscillator (in the convention m = ω = ~ = 1) is described by a position operator q̂, a momentum operator p̂ and a ...