Search results for "pun"
showing 10 items of 1409 documents
Intermittent-Type Chaos in Nonsinusoidal Driven Oscillators
2000
The intermittent-type chaos occurring in rf- and dc- nonsinusoidal driven oscillators is investigated analytically and numerically. The attention is focused on a general class of oscillators in which the total potential VRP(,r) is the Remoissenet-Peyrard potential which has constant amplitude and is 2π-periodic in , and whose shape can be varied as a function of parameter r ( |r| < 1). A simple physical model for calculating analytically the Melnikov function is proposed. The onset of chaos is studied through an analysis of the phase space, a construction of the bifurcation diagram and a computation of the Lyapunov exponent. The parameter regions of chaotic behaviour predicted by the theore…
Chaotic Cyclotron and Hall Trajectories Due to Spin-Orbit Coupling
2020
We demonstrate that the synergistic effect of a gauge field, Rashba spin-orbit coupling (SOC), and Zeeman splitting can generate chaotic cyclotron and Hall trajectories of particles. The physical origin of the chaotic behavior is that the SOC produces a spin-dependent (so-called anomalous) contribution to the particle velocity and the presence of Zeeman field reduces the number of integrals of motion. By using analytical and numerical arguments, we study the conditions of chaos emergence and report the dynamics both in the regular and chaotic regimes. {We observe the critical dependence of the dynamic patterns (such as the chaotic regime onset) on small variations in the initial conditions …
Charge control in laterally coupled double quantum dots
2011
4 figuras, 4 páginas.-- PACS number(s): 78.67.Hc, 73.21.La, 78.55.Cr
Linear inverse filtering improves spatial separation of nonlinear brain dynamics: a simulation study.
2000
We examined topographic variations in nonlinear measures based on scalp voltages, which were generated by two simulated current dipoles each placed in a different hemisphere of a spherical volume conductor (three-shell model). Dipole dynamics were that of a three-torus and the x-component of the Lorenz-system and scalp voltage were calculated for a configuration of 29 electrode positions. Although estimates for correlation dimension D2 and Lyapunov exponent L1 were close to the theoretical values for the original time series, the simulated scalp voltage data showed almost no topographic resolution of dipole positions. In order to enhance topographic differentiation, we constructed linear in…
Rich dynamics and anticontrol of extinction in a prey-predator system
2019
This paper reveals some new and rich dynamics of a two-dimensional prey-predator system and to anticontrol the extinction of one of the species. For a particular value of the bifurcation parameter, one of the system variable dynamics is going to extinct, while another remains chaotic. To prevent the extinction, a simple anticontrol algorithm is applied so that the system orbits can escape from the vanishing trap. As the bifurcation parameter increases, the system presents quasiperiodic, stable, chaotic and also hyperchaotic orbits. Some of the chaotic attractors are Kaplan-Yorke type, in the sense that the sum of its Lyapunov exponents is positive. Also, atypically for undriven discrete sys…
Relaxation, postponement, and features of the attractor in a driven varactor oscillator
1990
The driven varactor oscillator is investigated by numerical integration of its ODEs using the standard model of circuit theory. Attention is given to some properties of the basic relaxation mechanism. For time dependent amplitudes of the sinusoidal driving voltage the post-ponement of the bifurcations is characterized by transient Lyapunov numbers. The postponement of the first bifurcation shows the same dependence on the sweep velocity as in the case of the nonautonomous quadratic map. The shapes of the attractors are displayed in extended phase space. Generalized Renyi-dimensionsD 0 andD 1 have been determined in the chaotic region. A corresponding twodimensional Pioncare map indicates se…
Chaotic Antiferromagnetic Nano-Oscillator driven by Spin-Torque
2021
We theoretically describe the behavior of a terahertz nano-oscillator based on an anisotropic antiferromagnetic dynamical element driven by spin torque. We consider the situation when the polarization of the spin-current is perpendicular to the external magnetic field applied along the anisotropy easy-axis. We determine the domain of the parametric space (field, current) where the oscillator demonstrates chaotic dynamics. Characteristics of the chaotic regimes are analyzed using conventional techniques such as spectra of the Lyapunov exponents. We show that the threshold current of the chaos appearance is particularly low in the vicinity of the spin-flop transition. In this regime, we consi…
Refractive index change dependence on Ge(1) defects inγ-irradiated Ge-doped silica
2009
We present an experimental study regarding the effects of the $\ensuremath{\gamma}$ radiation on silica glass doped with Ge up to $10\text{ }000$ ppm molar produced by the sol-gel technique. We have determined the irradiation-induced changes in the refractive index $(\ensuremath{\Delta}n)$ as a function of the oxygen deficiency of the samples, evaluated from the ratio between the germanium lone pair centers (GLPC) and the Ge content. $\ensuremath{\Delta}n$ at 1500 nm have been estimated using optical-absorption spectra in the range 1.5--6 eV. We have found that $\ensuremath{\Delta}n$ is independent of Ge differences for GLPC/Ge values $l{10}^{\ensuremath{-}4}$, while it depends on Ge for la…
Pool punishment in public goods games: How do sanctioners’ incentives affect us?
2021
Abstract Centralized sanctioning in social dilemmas has been shown to increase efficiency with respect to standard decentralized peer punishment. In this context, we explore the impact of sanctioners’ motivations through their payoff scheme, not only on their actions but also on the actions of the monitored individuals. To do so, we compare the implementation of two different payoff schemes for the monitor in a centralized sanctioning framework: (i) a fixed payoff scheme and (ii) a variable payoff scheme contingent on the level of cooperation achieved. We find that providing the sanctioner with a contingent payoff has a negative impact on contributions. This occurs although sanctioners impl…
ULTRASOUND (US) GUIDED DIAGNOSTIC PROCEDURES AND MALIGNANT PLEURAL EFFUSIONS
2022
Introduction: Malignant pleural effusion (PE) is a rather frequent complication of several intrathoracic and extrathoracic tumors and has an incidence of about 660 patients per million inhabitants per year. Materials and methods: We retrospectively studied (2000 to 2018) the utility of US guided percutaneous puncture (PP) of PE, in the diagnosis/therapy of 121 patients (67 women and 54 men) with PE and suspected malignant neoplasm, mean age 52 years (39-78 years), Results: The diagnostic accuracy of the US guided PP fluid examination, (diagnoses of malignant PE), was 91.7% (111/121), with sensitivity of 89.5% (86/96) and specificity of 100%. (25/25). 10 patients did not have confirmation of…