Browsing Mathematics by Title
Now showing items 5271 of 290

Computation of the response functions of spiral waves in active media
(American Physical Society, 2009)Rotating spiral waves are a form of selforganization observed in spatially extended systems of physical, chemical, and biological natures. A small perturbation causes gradual change in spatial location of spiral's rotation ... 
A Computer Simulation Study of Anatomy Induced Drift of Spiral Waves in the Human Atrium
(Hindawi Publishing Corporation, 2014)The interaction of spiral waves of excitation with atrial anatomy remains unclear. This simulation study isolates the role of atrial anatomical structures on spiral wave spontaneous drift in the human atrium. We implemented ... 
Conditions for propagation and block of excitation in an asymptotic model of atrial tissue.
(2006)Detailed ionic models of cardiac cells are difficult for numerical simulations because they consist of a large number of equations and contain small parameters. The presence of small parameters, however, may be used for ... 
Conditions for sinktosource transitions and runaway feedbacks from the land carbon cycle
(Cambridge University Press, 200602)The first GCM climatecarbon cycle simulation indicated that the land biosphere could provide a significant acceleration of 21st century climate change (Cox et al. 2000). In this numerical experiment the carbon storage was ... 
Cone exchange transformations and boundedness of orbits
(Cambridge University Press, 2010)We introduce a class of twodimensional piecewise isometries on the plane that we refer to as cone exchange transformations (CETs). These are generalizations of interval exchange transformations (IETs) to 2D unbounded ... 
Confidence in Classification: A Bayesian Approach
(Springer Verlag, 2006)Bayesian classification is currently of considerable interest. It provides a strategy for eliminating the uncertainty associated with a particular choice of classifiermodel parameters, and is the optimal decisiontheoretic ... 
Control of scrollwave turbulence using resonant perturbations
(American Physical Society, 2008)Turbulence of scroll waves is a sort of spatiotemporal chaos that exists in threedimensional excitable media. Cardiac tissue and the BelousovZhabotinsky reaction are examples of such media. In cardiac tissue, chaotic ... 
Controlbased continuation of unstable periodic orbits
(American Society of Mechanical Engineers (ASME), 2011)We present an experimental procedure to track periodic orbits through a fold (saddlenode) bifurcation and demonstrate it with a parametrically excited pendulum experiment where the tracking parameter is the amplitude of ... 
Controlling unstable chaos: stabilizing chimera states by feedback
(American Physical Society, 2014)We present a control scheme that is able to find and stabilize an unstable chaotic regime in a system with a large number of interacting particles. This allows us to track a high dimensional chaotic attractor through a ... 
Convergence to local random attractors
(Taylor & Francis, 2003)Random attractors allow one to classify qualitative and quantitative aspects of the longtime behaviour of stochastically forced systems viewed as random dynamical systems (RDS) in an analogous way to attractors for ... 
Correcting the finiteensemble bias of the ignorance score
(Royal Meteorological Society, 2015)This study considers the application of the Ignorance Score (also known as the Logarithmic Score) in the context of ensemble verification. In particular, we consider the case where an ensemble forecast is transformed to a ... 
Countertraveling waves in rotating RayleighBénard convection.
(American Physical Society, 2008)Linear and nonlinear countertraveling waves in a fluidfilled annular cylinder with realistic noslip boundary conditions uniformly heated from below and rotating about a vertical axis are investigated. When the gap of ... 
Criteria for robustness of heteroclinic cycles in neural microcircuits.
(BioMed Central / SpringerOpen, 2011)We introduce a test for robustness of heteroclinic cycles that appear in neural microcircuits modeled as coupled dynamical cells. Robust heteroclinic cycles (RHCs) can appear as robust attractors in LotkaVolterratype ... 
Critical fronts in initiation of excitation waves
(American Physical Society, 2007)We consider the problem of initiation of propagating waves in a onedimensional excitable fiber. In the FitzHughNagumo theory, the key role is played by "critical nucleus" and "critical pulse" solutions whose (center) ... 
Cycling chaos: its creation, persistence and loss of stability in a model of nonlinear magnetoconvection
(Elsevier, 1998)We examine a model system where attractors may consist of a heteroclinic cycle between chaotic sets; this `cycling chaos' manifests itself as trajectories that spend increasingly long periods lingering near chaotic invariant ... 
Cycling chaotic attractors in two models for dynamics with invariant subspaces
(American Institute of Physics, 2004)Nonergodic attractors can robustly appear in symmetric systems as structurally stable cycles between saddletype invariant sets. These saddles may be chaotic giving rise to "cycling chaos." The robustness of such attractors ... 
Decelerating defects and nonergodic critical behaviour in a unidirectionally coupled map lattice
(Elsevier, 2003)We examine a coupled map lattice (CML) consisting of an infinite chain of logistic maps coupled in one direction by inhibitory coupling. We find that for sufficiently strong coupling strength there are dynamical states ... 
Declining summer snowfall in the Arctic: Causes, impacts and feedbacks
(Springer Verlag, 2012)Recent changes in the Arctic hydrological cycle are explored using in situ observations and an improved atmospheric reanalysis data set, ERAInterim. We document a pronounced decline in summer snowfall over the Arctic Ocean ... 
Dengue epidemic early warning system for Brazil
(UNISDR Scientific and Technical Advisory Group, 2015)The problem Brazil has reported more cases of dengue fever than anywhere else in the world this century1. Many cities have tropical and subtropical climate conditions that allow the dengue mosquito to thrive during warmer, ... 
Dependency of global mean precipitation on surface temperature
(American Geophysical Union (AGU), 2008)We investigate the causes of temperature dependent changes in global precipitation in contemporary General Circulation Models (GCMs) subjected to a doubling of atmospheric CO2 concentration. By analyzing the energy budget ...