SPATIOTEMPORAL IRREGULARITY IN A TWO-DIMENSIONAL MODEL OF CARDIAC TISSUE

1991 ◽  
Vol 01 (01) ◽  
pp. 219-225 ◽  
Author(s):  
A. V. PANFILOV ◽  
A. V. HOLDEN
Keyword(s):  
Cardiac Tissue ◽  
Numerical Solutions ◽  
Spiral Waves ◽  
Excitable Medium ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Two Dimensional Model ◽  
Solutions Of Equations

Meandering spiral waves are well-known solutions of equations that represent a two-dimensional excitable medium. Numerical solutions of a model for a sheet of cardiac tissue show transient meandering vortices that break down spontaneously into spatiotemporal irregularity.

Chaotic Phenomena in Fast Plastic Deformation (in the Case of Cutting)

2005 ◽  
Vol 473-474 ◽  
pp. 369-374 ◽  
Author(s):  
Zoltán Pálmai
Keyword(s):  
Plastic Deformation ◽  
Jacobian Matrix ◽  
Extreme Conditions ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Chaotic Phenomena ◽  
Two Dimensional Model ◽  
Solutions Of Equations ◽  
Autonomous Differential Equations ◽  
Continuous Chip

Technologies applied in machining metals are often characterised by highly localised shear strain, which can be regarded nearly as adiabatic, and which might lead to thermoplastic instability in certain cases. In cutting, similar incidents can be observed in the shear zone, in which γ=2–50, dγ/dt≈104 s-1, dT/dt=106 K/s, and under such extreme conditions chaotic phenomena may occur occasionally. Chip formation can be described by a two-dimensional model, where the variation of shear stress τ and temperature T in time are given by autonomous differential equations, while the material characteristics are determined by exponential constitutive functions. The solutions of equations can be classified by the coefficients of the characteristic equation of the Jacobian matrix. Two types of stable focuses and Hopf bifurcation can possibly occur, which corresponds to the two types of chips; continuous chip and segmental chip. The model should be broadened to describe the typical chaotic phenomena.

scholarly journals Living cardiac tissue slices: An organotypic pseudo two-dimensional model for cardiac biophysics research

2014 ◽  
Vol 115 (2-3) ◽  
pp. 314-327 ◽  
Author(s):  
Ken Wang ◽  
Derek Terrar ◽  
David J. Gavaghan ◽  
Razik Mu-u-min ◽  
Peter Kohl ◽  
...  
Keyword(s):  
Cardiac Tissue ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Tissue Slices ◽  
Two Dimensional Model

Commitment to pro- versus counter-attitudinal behavior and the dynamics of social representations

2002 ◽  
Vol 61 (1) ◽  
pp. 34-44 ◽  
Author(s):  
Eric Tafani ◽  
Lionel Souchet
Keyword(s):  
Higher Education ◽  
Social Representations ◽  
Cognitive Restructuring ◽  
Social Representation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Social Actions ◽  
The Social ◽  
Two Dimensional Model ◽  
Students Attitudes

This research uses the counter-attitudinal essay paradigm ( Janis & King, 1954 ) to test the effects of social actions on social representations. Thus, students wrote either a pro- or a counter-attitudinal essay on Higher Education. Three forms of counter-attitudinal essays were manipulated countering respectively a) students’ attitudes towards higher education; b) peripheral beliefs or c) central beliefs associated with this representation object. After writing the essay, students expressed their attitudes towards higher education and evaluated different beliefs associated with it. The structural status of these beliefs was also assessed by a “calling into question” test ( Flament, 1994a ). Results show that behavior challenging either an attitude or peripheral beliefs induces a rationalization process, giving rise to minor modifications of the representational field. These modifications are only on the social evaluative dimension of the social representation. On the other hand, when the behavior challenges central beliefs, the same rationalization process induces a cognitive restructuring of the representational field, i.e., a structural change in the representation. These results and their implications for the experimental study of representational dynamics are discussed with regard to the two-dimensional model of social representations ( Moliner, 1994 ) and rationalization theory ( Beauvois & Joule, 1996 ).

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