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Journal articles on the topic 'Spiral wave'

Author: Grafiati

Published: 4 June 2021

Last updated: 6 February 2022

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1

Campos, L. M. B. C., and P. J. S. Gil. "On spiral coordinates with application to wave propagation." Journal of Fluid Mechanics 301 (October 25, 1995): 153–73. http://dx.doi.org/10.1017/s0022112095003843.

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We introduce a possibly new system of orthogonal curvilinear coordinates, whose coordinate curves are logarithmic spirals in the plane, supplemented by a cylindrical coordinate for three dimensions. It is shown that plane spiral coordinates form a oneparameter family, with equal scale factors along the two orthogonal coordinate curves, and constant Christoffel symbols. The equations of magnetohydrodynamics, which include those of fluid mechanics, are written in spiral coordinates and used to find a state of magnetohydrostatic equilibrium under a radial gravity field and spiral magnetic field,

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2

DELLNITZ, MICHAEL, MARTIN GOLUBITSKY, ANDREAS HOHMANN, and IAN STEWART. "SPIRALS IN SCALAR REACTION–DIFFUSION EQUATIONS." International Journal of Bifurcation and Chaos 05, no. 06 (1995): 1487–501. http://dx.doi.org/10.1142/s0218127495001149.

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Spiral patterns have been observed experimentally, numerically, and theoretically in a variety of systems. It is often believed that these spiral wave patterns can occur only in systems of reaction–diffusion equations. We show, both theoretically (using Hopf bifurcation techniques) and numerically (using both direct simulation and continuation of rotating waves) that spiral wave patterns can appear in a single reaction–diffusion equation [ in u(x, t)] on a disk, if one assumes "spiral" boundary conditions (ur = muθ). Spiral boundary conditions are motivated by assuming that a solution is infin

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3

BIKTASHEVA, I. V., A. V. HOLDEN, and V. N. BIKTASHEV. "LOCALIZATION OF RESPONSE FUNCTIONS OF SPIRAL WAVES IN THE FITZHUGH–NAGUMO SYSTEM." International Journal of Bifurcation and Chaos 16, no. 05 (2006): 1547–55. http://dx.doi.org/10.1142/s0218127406015490.

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Dynamics of spiral waves in perturbed, e.g. slightly inhomogeneous or subject to a small periodic external force, two-dimensional autowave media can be described asymptotically in terms of Aristotelean dynamics, so that the velocities of the spiral wave drift in space and time are proportional to the forces caused by the perturbation. The forces are defined as a convolution of the perturbation with the spirals Response Functions, which are eigenfunctions of the adjoint linearized problem. In this paper we find numerically the Response Functions of a spiral wave solution in the classic excitabl

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4

Luo, Jinming, Xingyong Zhang, and Jun Tang. "Complex-Periodic Spiral Waves Induced by Linearly Polarized Electric Field in the Excitable Medium." International Journal of Bifurcation and Chaos 29, no. 05 (2019): 1950071. http://dx.doi.org/10.1142/s0218127419500718.

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Complex-periodic spiral waves are investigated extensively in the oscillatory medium. In this paper, the linearly polarized electric field (LPEF) is employed to induce complex-periodic spiral waves in the excitable medium with abnormal dispersion. As the amplitude of LPEF is increased beyond a threshold, the simple-periodic spiral wave converts into an irregularly complex-periodic one, in which, the local dynamics exhibit several regular spikes followed by one missed spiking period. Furthermore, with the increase of the LPEF amplitude, the missed spiking period follows different numbers of reg

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NIKOLAEV, E. V., V. N. BIKTASHEV, and A. V. HOLDEN. "ON BIFURCATIONS OF SPIRAL WAVES IN THE PLANE." International Journal of Bifurcation and Chaos 09, no. 08 (1999): 1501–16. http://dx.doi.org/10.1142/s021812749900105x.

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We describe the simplest bifurcations of spiral waves in reaction–diffusion systems in the plane and present the list of model systems. One-parameter bifurcations of one-armed spiral waves are fold and Hopf bifurcations. Multiarmed spiral waves may additionally undergo a period-doubling pitchfork bifurcation, when two congruent spiral wave solutions, having the "double" period, branch from the original spiral wave at the bifurcation point.

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LEI, AI ZHONG, QIAN SHU LI, WEIGUO XU, and DAIPING HU. "SPIRAL WAVE MAINTAINED BY NOISE." Fluctuation and Noise Letters 04, no. 03 (2004): L447–452. http://dx.doi.org/10.1142/s0219477504002051.

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The effect of Gaussian white noise on a chemical wavefront is studied in a modified FitzHugn–Nagumo model by applying numerical simulations. A rotating spiral waves can be formed if the medium is excitable enough and the fronts has a free end, when the reaction diffusion system is disturbed by a certain non-zero level noise. It is counterintuitive that noise plays a constructive role in the product and propagation of single spiral waves in this letter. Weak or strong noise will make against the product and propagation of spiral waves. In a certain noise level, spiral wave can be maintained in

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7

Punacha, Shreyas, Sebastian Berg, Anupama Sebastian, Valentin I. Krinski, Stefan Luther, and T. K. Shajahan. "Spiral wave unpinning facilitated by wave emitting sites in cardiac monolayers." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2230 (2019): 20190420. http://dx.doi.org/10.1098/rspa.2019.0420.

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Rotating spiral waves of electrical activity in the heart can anchor to unexcitable tissue (an obstacle) and become stable pinned waves. A pinned rotating wave can be unpinned either by a local electrical stimulus applied close to the spiral core, or by an electric field pulse that excites the core of a pinned wave independently of its localization. The wave will be unpinned only when the pulse is delivered inside a narrow time interval called the unpinning window (UW) of the spiral. In experiments with cardiac monolayers, we found that other obstacles situated near the pinning centre of the s

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Kuo, Samuel R., and Natalia A. Trayanova. "Action potential morphology heterogeneity in the atrium and its effect on atrial reentry: a two-dimensional and quasi-three-dimensional study." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 364, no. 1843 (2006): 1349–66. http://dx.doi.org/10.1098/rsta.2006.1776.

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Atrial fibrillation (AF) is believed to be perpetuated by recirculating spiral waves. Atrial structures are often characterized with action potentials of varying morphologies; however, the role of the structure-dependent atrial electrophysiological heterogeneity in spiral wave behaviour is not well understood. The purpose of this study is to determine the effect of action potential morphology heterogeneity associated with the major atrial structures in spiral wave maintenance. The present study also focuses on how this effect is further modulated by the presence of the inherent periodicity in

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9

Lu, Wei, Yu Lan, Rongzhen Guo, Qicheng Zhang, Shichang Li, and Tianfang Zhou. "Spiral Sound Wave Transducer Based on the Longitudinal Vibration." Sensors 18, no. 11 (2018): 3674. http://dx.doi.org/10.3390/s18113674.

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A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite ele

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10

Wang, Chunni, Jun Ma, Bolin Hu, and Wuyin Jin. "Formation of multi-armed spiral waves in neuronal network induced by adjusting ion channel conductance." International Journal of Modern Physics B 29, no. 07 (2015): 1550043. http://dx.doi.org/10.1142/s0217979215500435.

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The Hodgkin–Huxley neuron model is used to describe the local dynamics of nodes in a two-dimensional regular network with nearest-neighbor connections. Multi-armed spiral waves emerge when a group of spiral waves rotate the same core synchronously. Here we have numerically investigated how multi-armed spiral waves are formed in such a system. Under the appropriate conditions, multi-armed spiral waves were able to develop as a result of adjusting the conductance of ion channels of particular neurons in the network. In a realistic neuron model, it can be practiced by blocking potassium of ion ch

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11

DAVTDENKO, JORGE M. "Spiral Wave Activity:." Journal of Cardiovascular Electrophysiology 4, no. 6 (1993): 730–46. http://dx.doi.org/10.1111/j.1540-8167.1993.tb01258.x.

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12

Diks, C., B. Hoekstra, and J. Degoede. "Spiral wave dynamics." Chaos, Solitons & Fractals 5, no. 3-4 (1995): 645–60. http://dx.doi.org/10.1016/0960-0779(93)e0047-f.

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13

YUAN, GUO-YONG, XIAO-MING WANG, GUANG-RUI WANG, and SHI-PING YANG. "EFFECT OF EXTERNAL PERIODIC PULSES ON SPIRAL DYNAMICS AND CONTROL OF SPIRAL WAVES." International Journal of Modern Physics B 27, no. 28 (2013): 1350158. http://dx.doi.org/10.1142/s0217979213501580.

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In this paper, we study the effect of external periodic pulses on spiral dynamics. Resonant entrainment bands were observed on the period T-axis, and T is close to rational multiples of the path curvature period of the spiral tip on the bands. It is also shown that spiral waves are drifted and eliminated by applying the driving method with suitable control parameters, and we reveal the mechanism which forces the spiral wave to periodically shift and rotate. In the domain near the spiral tip, the bidirectional wave excitations are periodically generated by external pulses, and each excitation i

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14

Majumder, Rupamanjari, Rahul Pandit, and A. V. Panfilov. "Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue." American Journal of Physiology-Heart and Circulatory Physiology 307, no. 7 (2014): H1024—H1035. http://dx.doi.org/10.1152/ajpheart.00593.2013.

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Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast in

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15

YUAN, GUOYONG, ZHICHENG FENG, AIGUO XU, GUANGRUI WANG, and SHAOYING CHEN. "DYNAMICS IN EXCITABLE MEDIA SUBJECTED TO A SPECIFIC SPATIOTEMPORAL WAVE UNDER TWO SCHEMES." International Journal of Bifurcation and Chaos 22, no. 06 (2012): 1250148. http://dx.doi.org/10.1142/s0218127412501489.

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The dynamics in excitable media driven by a specific spatiotemporal wave are studied by investigating wave states, the motion of tips and synchronized behaviors. We demonstrate that multiple-armed spiral waves can be generated in excitable media with rest initial conditions by directly injecting a rigidly rotating spiral wave, also that the meandering driver can induce the spiral wave, with the wider excited parts and the same frequency as the driving wave, in the driven system. It is more interesting to find that the higher similarity between the driving and driven waves occurs when the drivi

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16

MA, JUN, AI-HUA ZHANG, JUN TANG, and WU-YIN JIN. "COLLECTIVE BEHAVIORS OF SPIRAL WAVES IN THE NETWORKS OF HODGKIN-HUXLEY NEURONS IN PRESENCE OF CHANNEL NOISE." Journal of Biological Systems 18, no. 01 (2010): 243–59. http://dx.doi.org/10.1142/s0218339010003275.

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Collective behaviors of spiral waves in the networks of Hodgkin-Huxley neuron are investigated. A stable rotating spiral wave can be developed to occupy the quiescent areas in networks of neurons by selecting appropriate initial values for the variables in the networks of neurons. In our numerical studies, most neurons are quiescent and finite (few) numbers of neurons are selected with different values to form a spiral seed. In this way, neurons communicating are carried by propagating spiral wave to break through the quiescent domains (areas) in networks of neurons. The effect of membrane tem

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MA, JUN, YA JA, JUN TANG, and YONG CHEN. "PARAMETER FLUCTUATION-INDUCED PATTERN TRANSITION IN THE COMPLEX GINZBURG–LANDAU EQUATION." International Journal of Modern Physics B 24, no. 23 (2010): 4481–500. http://dx.doi.org/10.1142/s0217979210056530.

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Parameter fluctuation, which is often induced by the noise, temperature, deformation of the media etc., plays an important role in changing the dynamics of the system. In this paper, the problem of parameter fluctuation-induced pattern transition in the Complex Ginzburg–Landau equation (CGLE) is investigated. At first, the perpendicular-gradient initial values are used to generate spiral wave and spiral turbulence under appropriate parameters. At second, the parameter is perturbed with the periodical and/or random signal to simulate the parameter fluctuation, respectively. Then a class of line

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18

LI, FAN, and JUN MA. "SELECTION OF SPIRAL WAVE IN THE COUPLED NETWORK UNDER GAUSSIAN COLORED NOISE." International Journal of Modern Physics B 27, no. 21 (2013): 1350115. http://dx.doi.org/10.1142/s0217979213501154.

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The selection and breakup of spiral wave in a coupled network is investigated by imposing Gaussian colored noise on the network, respectively. The dynamics of each node of the network is described by a simplified Chua circuit, and nodes are uniformly placed in a two-dimensional array with nearest-neighbor connection type. The transition of spiral wave is detected by changing the coupling intensity, intensity and correlation time τ in the noise. A statistical variable is used to discern the parameter region for breakup of spiral wave and robustness to external noise. Spiral waves emerge in the

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Zykov, V. S. "Spiral wave initiation in excitable media." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 376, no. 2135 (2018): 20170379. http://dx.doi.org/10.1098/rsta.2017.0379.

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Spiral waves represent an important example of dissipative structures observed in many distributed systems in chemistry, biology and physics. By definition, excitable media occupy a stationary resting state in the absence of external perturbations. However, a perturbation exceeding a threshold results in the initiation of an excitation wave propagating through the medium. These waves, in contrast to acoustic and optical ones, disappear at the medium's boundary or after a mutual collision, and the medium returns to the resting state. Nevertheless, an initiation of a rotating spiral wave results

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20

Pérez-Muñuzuri, V., M. Gómez-Gesteira, and V. Pérez-Villar. "A geometrical-kinematical approach to spiral wave formation: super-spiral waves." Physica D: Nonlinear Phenomena 64, no. 4 (1993): 420–30. http://dx.doi.org/10.1016/0167-2789(93)90053-4.

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21

Wu, Yong, Bing Wang, Xiaoxiao Zhang, and Hao Chen. "Spiral wave of a two-layer coupling neuronal network with multi-area channels." International Journal of Modern Physics B 33, no. 29 (2019): 1950354. http://dx.doi.org/10.1142/s0217979219503545.

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Using the Hindmarsh–Rose (HR) model, a two-layer neuronal network is constructed to study the spiral wave dynamics. The first layer generates spiral wave induced by random values of boundary under appropriate coupling intensity and external force, and the second layer is in the different states. Coupling channels between the two layers are set in multiple areas and spiral wave of first layer affect second layer via the coupling channels. The spatiotemporal pattern of neuronal network is investigated in the second layer. It is shown that spiral wave can be found under appropriate conditions, mu

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22

Yashima, Masaaki, Toshihiko Ohara, Yoshiyuki Hirayama, Takao Katoh, and Kyoichi Mizuno. "Spiral Wave during Ventricular Fibrillation." Nihon Ika Daigaku Igakkai Zasshi 5, no. 2 (2009): 74. http://dx.doi.org/10.1272/manms.5.74.

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23

Xu, Li Jun, Guo Yong Yuan, and Zhen Cheng Luo. "Effect of Dichotomous Noise on Dynamics of Spiral Waves." Applied Mechanics and Materials 538 (April 2014): 451–54. http://dx.doi.org/10.4028/www.scientific.net/amm.538.451.

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This paper mainly researched the effect of dichotomous noise on the dynamics of spiral wave, provided a method to eliminate spiral waves by dichotomous noise. Spiral wave dynamics show regular changes under the action of dichotomous noise with noise strength, time correlation parameter, this rule change can be explained by spectral analysis.

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HUANG, LONG, JUN MA, JUN TANG, and FAN LI. "TRANSITION OF ORDERED WAVES IN NEURONAL NETWORK INDUCED BY DIFFUSIVE POISONING OF ION CHANNELS." Journal of Biological Systems 21, no. 01 (2013): 1350002. http://dx.doi.org/10.1142/s0218339013500022.

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Normal physiological activities are often affected by some drugs, and some ion channels are blocked due to the katogene of drugs. This paper investigates the propagation of ordered waves in neuronal networks induced by diffusive poisoning, where the process is measured by increasing the number of neurons in the poisoned area of the networks. A coefficient of poisoning K is defined to measure the time units from one poisoned site to the adjacent site, a smaller K means that more neurons are poisoned in a certain period (a higher poisoning speed). A statistical factor of synchronization R in the

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Guo-Yong, Yuan, Zhang Guang-Cai, Wang Guang-Rui, Chen Shi-Gang, and Sun Peng. "Elimination of Spiral Waves and Competition between Travelling Wave Impulses and Spiral Waves." Chinese Physics Letters 22, no. 2 (2005): 291–94. http://dx.doi.org/10.1088/0256-307x/22/2/007.

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Agladze, Konstantin, Matthew W. Kay, Valentin Krinsky, and Narine Sarvazyan. "Interaction between spiral and paced waves in cardiac tissue." American Journal of Physiology-Heart and Circulatory Physiology 293, no. 1 (2007): H503—H513. http://dx.doi.org/10.1152/ajpheart.01060.2006.

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For prevention of lethal arrhythmias, patients at risk receive implantable cardioverter-defibrillators, which use high-frequency antitachycardia pacing (ATP) to convert tachycardias to a normal rhythm. One of the suggested ATP mechanisms involves paced-induced drift of rotating waves followed by their collision with the boundary of excitable tissue. This study provides direct experimental evidence of this mechanism. In monolayers of neonatal rat cardiomyocytes in which rotating waves of activity were initiated by premature stimuli, we used the Ca2+-sensitive indicator fluo 4 to observe propaga

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Muhammad, Ibrahim, and Hao Bai. "Circumferential and Spiral Waves in Piezoelectric Cylinders." Advanced Materials Research 622-623 (December 2012): 142–46. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.142.

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Study of the guided waves in piezoelectric cylinders based on a semi-analytical finite element method is presented. In the study, the dispersion equation was formulated as a generalized eigenvalue problem by treating mechanical displacements and electric potential with one dimensional quadratic finite element model through the thickness of the cylinder. Here the general eigenvalue problem is depended on three parameters, namely, the frequency, the axial wave number and the circumferential wave. A non-integer circumferential wave is introduced here for studying the guided spiral wave. A wave sp

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Ceperley, Peter H., and Alon Koren. "Acoustic spiral wave field." Journal of the Acoustical Society of America 93, no. 4 (1993): 2278. http://dx.doi.org/10.1121/1.406581.

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Qian Yu. "Spatiotemporal modulation induced coexistence of meandering spiral wave and travelling spiral wave." Acta Physica Sinica 62, no. 5 (2013): 058201. http://dx.doi.org/10.7498/aps.62.058201.

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Sellwood, J. A. "The Lifetimes of Spirals and Bars." Proceedings of the International Astronomical Union 10, H16 (2012): 321. http://dx.doi.org/10.1017/s1743921314005857.

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Simulations of isolated galaxy disks that are stable against bar formation readily manifest multiple, transient spiral patterns. It therefore seems likely that some spirals in real galaxies are similarly self-excited, although others are clearly driven by tidal interactions or by bars. The rapidly changing appearance of simulated spirals does not, however imply that the patterns last only a fraction of an orbit. Power spectrum analysis reveals a few underlying, longer-lived spiral waves that turn at different rates, which when super-posed give the appearance of swing-amplified transients. Thes

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Foerster, P., S. C. Muller, and B. Hess. "Curvature and spiral geometry in aggregation patterns of Dictyostelium discoideum." Development 109, no. 1 (1990): 11–16. http://dx.doi.org/10.1242/dev.109.1.11.

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Aggregation patterns of the slime mould Dictyostelium discoideum were recorded using dark-field equipment combined with video techniques. Computerized image processing allowed the analysis of wave collision structures, expanding concentric circles and rotating spirals in terms of wave velocity and front geometry, as previously done in the Belousov-Zhabotinskii reaction, a chemical system showing similar patterns. We verified the linear relationship between the normal velocity and the curvature of wave fronts predicted by a reaction-diffusion model. The proportionality factor, which in this cas

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Kharche, Sanjay R., Irina V. Biktasheva, Gunnar Seemann, Henggui Zhang, and Vadim N. Biktashev. "A Computer Simulation Study of Anatomy Induced Drift of Spiral Waves in the Human Atrium." BioMed Research International 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/731386.

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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 realistic and idealised 3D human atria models to investigate the functional impact of anatomical structures on the long-term (∼40 s) behaviour of spiral waves. The drift of a spiral wave was quantified by tracing its tip trajectory, which was correlated to atrial anatomical features. The interaction of spiral waves with the following idealised geometries was investigated: (

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Paullet, Joseph E., та G. Bard Ermentrout. "Spiral Waves in Spatially Discrete λ-ω Systems". International Journal of Bifurcation and Chaos 08, № 01 (1998): 33–40. http://dx.doi.org/10.1142/s0218127498000036.

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The existence of stable spiral wave solutions in a spatially discrete λ-ω system is proven. The waves are shown to exist only if the coupling parameter d is sufficiently small. There is a critical value dc such that if d>dc, the spiral wave solution ceases to exists. This is in agreement with the behavior of such waves in spatially continuous λ-ω systems on finite domains.

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Dong, Xunde, Chen Song, and Cong Wang. "Spiral Tip Identification via Deterministic Learning." International Journal of Bifurcation and Chaos 29, no. 03 (2019): 1950040. http://dx.doi.org/10.1142/s0218127419500408.

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A spiral tip can be considered as a wave source, i.e. a wave is sent out after the tip rotates one circle. Therefore, the dynamics of the spiral tip is vital to understand the behavior of spiral waves. In this paper, we study the spiral tip dynamics from a new perspective by using deterministic learning. A Barkley model described by partial differential equations (PDEs) is employed to illustrate the method. It is first transformed into a set of ordinary differential equations (ODEs) by using finite difference method. Then, the position states of spiral tip are extracted from the spiral wave ge

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Qiu, Hua, Zheng Su, and Cha Xiong. "Experimental investigation on multi-cycle two-phase spiral pulse detonation tube of two configurations." Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 233, no. 11 (2018): 4166–75. http://dx.doi.org/10.1177/0954410018817455.

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The spiral tube structure is an effective method to shorten the axial length of the pulse detonation chamber. In this article, spiral pulsed detonation tube with two kinds of spiral configuration was experimentally investigated. Liquid gasoline and air were used as fuel and oxidant, respectively, and equivalence ratios were controlled to about 1.0. Based on the transient pressure along the tube, the propagation characteristics of the pressure waves in the multi-cycle spiral pulsed detonation tubes, such as pressure peaks, wave velocities and propagation process, were analyzed. Results showed t

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MA, JUN, JUN TANG, CHUN-NI WANG, and YA JIA. "PROPAGATION AND SYNCHRONIZATION OF Ca2+ SPIRAL WAVES IN EXCITABLE MEDIA." International Journal of Bifurcation and Chaos 21, no. 02 (2011): 587–601. http://dx.doi.org/10.1142/s0218127411028635.

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Ca2+ spiral wave is observed in a large number of cell types. Based on a Ca2+ model presented by Atri et al., the propagation and synchronization of the intracellular Ca2+ spiral waves are numerically studied and some interesting results are obtained. (i) The largest Lyapunov exponents versus bifurcation parameter is calculated to investigate the oscillation of Ca2+ and it is found that almost all of the largest Lyapunov exponents are negative except for some others that are very close to zero (with an order of magnitude about 10-4 to 10-5). (ii) The two controllable parameters — the concentra

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Li, Guang-Zhao, Yong-Qi Chen, Guo-Ning Tang, and Jun-Xian Liu. "Spiral Wave Dynamics in a Response System Subjected to a Spiral Wave Forcing." Chinese Physics Letters 28, no. 2 (2011): 020504. http://dx.doi.org/10.1088/0256-307x/28/2/020504.

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Sawa, T., and M. Fujimoto. "Bisymmetric Spiral Magnetic Fields and Gravitational Instabilities of Galactic Disks." Symposium - International Astronomical Union 140 (1990): 125–26. http://dx.doi.org/10.1017/s0074180900189727.

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Linearized equations of motion are solved for the self-gravitating gaseous disk in interaction with the Lorentz force due to the bisymmetric spiral (BSS) magnetic fields. Since the pattern velocity of the BSS fields is very close to that of the spiral density wave, a nearly-resonant interaction occurs between these two waves to enhance spiral condensation of gas. The BSS fields seem to compensate the spiral density waves for their secular dispersion.

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Abdeen, Shameer, Daniel Kennefick, Julia Kennefick, et al. "Determining the co-rotation radii of spiral galaxies using spiral arm pitch angle measurements at multiple wavelengths." Monthly Notices of the Royal Astronomical Society 496, no. 2 (2020): 1610–19. http://dx.doi.org/10.1093/mnras/staa1596.

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ABSTRACT The spiral arms spanning disc galaxies are believed to be created by density waves that propagate through galactic discs. We present a novel method of finding the co-rotation radius where the spiral arm pattern speed matches the velocities of the stars within the disc. Our method uses an image-overlay technique, which involves tracing the arms of spiral galaxies on images observed in different wavelengths. Density wave theory predicts that spiral arms observed from different wavelengths show a phase crossing at the co-rotation radius. For the purpose of this study, 20 nearby galaxies

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Xie, Fagen, Zhilin Qu, Alan Garfinkel, and James N. Weiss. "Electrical refractory period restitution and spiral wave reentry in simulated cardiac tissue." American Journal of Physiology-Heart and Circulatory Physiology 283, no. 1 (2002): H448—H460. http://dx.doi.org/10.1152/ajpheart.00898.2001.

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Theoretical and experimental studies have shown that restitution of the cardiac action potential (AP) duration (APD) plays a major role in predisposing ventricular tachycardia to degenerate to ventricular fibrillation, whereas its role in atrial fibrillation is unclear. We used the Courtemanche human atrial cell model and the Luo-Rudy guinea pig ventricular model to compare the roles of electrical restitution in destabilizing spiral wave reentry in simulated two-dimensional homogeneous atrial and ventricular tissue. Because atrial AP morphology is complex, we also validated the usefulness of e

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Song, Chen, Xunde Dong, and Cong Wang. "Spiral Tip Recognition via Deterministic Learning." International Journal of Bifurcation and Chaos 30, no. 06 (2020): 2050093. http://dx.doi.org/10.1142/s0218127420500935.

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The spiral tip is vital to the understanding of the spiral wave behaviors. Most studies of spiral tip dynamics focused on the prevention, control, and elimination of spiral wave, while few studies focused on the recognition of spiral wave. In real systems with the spiral wave, the recognition of the spiral wave should be before control or elimination. In the paper, we study the recognition of the spiral tip via deterministic learning. It mainly consists of two phases: the identification phase and the recognition phase. In the identification phase, the dynamics of spiral tips of the training se

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CASSIA-MOURA, R., FAGEN XIE, and HILDA A. CERDEIRA. "EFFECT OF HETEROGENEITY ON SPIRAL WAVE DYNAMICS IN SIMULATED CARDIAC TISSUE." International Journal of Bifurcation and Chaos 14, no. 09 (2004): 3363–75. http://dx.doi.org/10.1142/s0218127404011375.

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There is considerable spatial heterogeneity in the electrical properties of the heart muscle and there are indications that anisotropic conduction may play an important role in the pathogenesis of clinical cardiac arrhythmias. Spiral waves of electrical activity are related to reentrant cardiac arrhythmias as ventricular tachycardia and ventricular fibrillation, and the generation of a wave breakup is hypothesized to underlie the transition from ventricular tachycardia to ventricular fibrillation — the leading cause of sudden cardiac death. Here we investigate the effect of heterogeneity on sp

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JACQUIR, S., S. BINCZAK, B. XU, et al. "INVESTIGATION OF MICRO SPIRAL WAVES AT CELLULAR LEVEL USING A MICROELECTRODE ARRAYS TECHNOLOGY." International Journal of Bifurcation and Chaos 21, no. 01 (2011): 209–23. http://dx.doi.org/10.1142/s0218127411028374.

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During cardiac arrhythmia, functional reentries may take the form of spiral waves. The purpose of this study was to induce spiral waves by an electrical stimulation of cultured neonatal rat cardiomyocytes using a microelectrode arrays technology. In basal conditions, cardiac muscle cells in monolayer culture displayed a planar wavefront propagation. External electrical impulse trains induced severe arrhythmia and spiral waves appeared. This in vitro generation of spiral wave opens a new way to test the anti-arrhythmic drugs and for strategies at microscopically scale.

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QIAN, YU, YUANYUAN MI, and XIAODONG HUANG. "CONTROL OF SPIRAL WAVE BREAKUP BY SPATIOTEMPORAL MODULATION." International Journal of Bifurcation and Chaos 21, no. 05 (2011): 1341–48. http://dx.doi.org/10.1142/s0218127411029203.

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The control of spiral wave breakup due to Doppler instability has been investigated. It is found that by applying the spatiotemporal modulation method with suitable control parameters, spiral wave breakup can be prevented. Further numerical simulations show that preventing spiral wave breakup is a result of the decrease of meandering motion of the spiral tip.

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Mckenzie, A., and J. Sneyd. "On the Formation and Breakup of Spiral Waves of Calcium." International Journal of Bifurcation and Chaos 08, no. 10 (1998): 2003–12. http://dx.doi.org/10.1142/s0218127498001650.

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We study spiral waves in a model of Ca 2+ dynamics in the Xenopus laevis oocyte. Spiral waves in the model were initiated by simulating the release of inositol 1,4,5-trisphosphate ( IP 3), a common experimental protocol. No artificial heterogeneities needed to be imposed on the system for the spontaneous formation of spiral waves. Increasing the size of the IP 3 additions caused a decrease in the rotation period, and the breakup of the spiral wave, irregular spatiotemporal patterns occurred. Similar disorganized patterns are sometimes seen experimentally; based on our simulations we predict th

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GRAY, RICHARD A., and JOSÉ JALIFE. "SPIRAL WAVES AND THE HEART." International Journal of Bifurcation and Chaos 06, no. 03 (1996): 415–35. http://dx.doi.org/10.1142/s0218127496000163.

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The human heart normally beats at a fairly regular rate of once per second. Under abnormal conditions, however, the heart may beat irregularly, at fast rates, leading quickly to death. The most dangerous of these irregular heart rhythms are due to recirculating electrical waves of activity. However, the detailed mechanisms of these “reentrant arrhythmias” are unclear. It has been suggested that these recirculating waves are spiral waves. This review article presents recent studies of the heart providing evidence that reentrant arrhythmias result from spiral waves of electrical activity. Spiral

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PUSTOVOIT, MARK A., and VALERY I. SBITNEV. ""SPIRAL WAVE–TRAVELING CLUSTERING" INTERMITTENCY AND 1/f-NOISE IN A 2D COUPLED MAP LATTICE." International Journal of Bifurcation and Chaos 09, no. 05 (1999): 929–37. http://dx.doi.org/10.1142/s0218127499000663.

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Intermittency of checkerboard spiral waves and traveling clusterings originating from sudden shrinking of the strange attractor of the 2D CML in the neighborhood of the saddle-node bifurcation boundary is found. A power-law probability density for lifetimes in the spiral wave (laminar) phase is observed, while in the checkerboard clusterings (bursting) phase the above quantity exhibits an exponential decay. This difference can be interpreted through the self-organized behavior of the spiral waves, and the passive relaxation of the disordered checkerboard clusterings.

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Dobysheva, Lyudmila V., and Anatoly K. Arzhnikov. "Theoretical Investigation of the Magnetic Order in FeAs." Solid State Phenomena 190 (June 2012): 11–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.190.11.

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The magnetic structure of the iron monoarsenide FeAs is studied using ﬁrst-principlescalculations. We consider the collinear and non-collinear (spin-spiral wave) magnetic orderingand magnetic anisotropy. It is analitically shown that a magnetic triaxial anisotropy resultsin a sum of two spin-spiral waves with opposite directions of wave vectors and diﬀerent spinamplitudes, so that the magnetic moments in two perpendicular directions do not equal eachother.

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Gottwald, Georg, Alain Pumir, and Valentin Krinsky. "Spiral wave drift induced by stimulating wave trains." Chaos: An Interdisciplinary Journal of Nonlinear Science 11, no. 3 (2001): 487–94. http://dx.doi.org/10.1063/1.1395624.

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Huang, Xiaoying, Weifeng Xu, Jianmin Liang, Kentaroh Takagaki, Xin Gao, and Jian-young Wu. "Spiral Wave Dynamics in Neocortex." Neuron 68, no. 5 (2010): 978–90. http://dx.doi.org/10.1016/j.neuron.2010.11.007.

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