The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Patrick Marquie - One of the best experts on this subject based on the ideXlab platform.
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Propagation Failure in discrete bistable reaction diffusion systems theory and experiments
Physical Review E, 2001Co-Authors: Jeanchristophe Comte, Saverio Morfu, Patrick MarquieAbstract:Wave front Propagation Failure is investigated in discrete bistable reaction-diffusion systems. We present a theoretical approach including dissipative effects and leading to an analytical expression of the critical coupling beyond which front Propagation can occur as a function of the nonlinearity threshold parameter. Our theoretical predictions are confirmed by numerical simulations and experimental results on an equivalent electrical diffusive lattice.
Jeanchristophe Comte - One of the best experts on this subject based on the ideXlab platform.
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Propagation Failure in discrete bistable reaction diffusion systems theory and experiments
Physical Review E, 2001Co-Authors: Jeanchristophe Comte, Saverio Morfu, Patrick MarquieAbstract:Wave front Propagation Failure is investigated in discrete bistable reaction-diffusion systems. We present a theoretical approach including dissipative effects and leading to an analytical expression of the critical coupling beyond which front Propagation can occur as a function of the nonlinearity threshold parameter. Our theoretical predictions are confirmed by numerical simulations and experimental results on an equivalent electrical diffusive lattice.
Thomas Erneux - One of the best experts on this subject based on the ideXlab platform.
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propagating waves in discrete bistable reaction diffusion systems
Physica D: Nonlinear Phenomena, 1993Co-Authors: Thomas Erneux, Gregoire NicolisAbstract:Abstract We consider a discrete bistable reaction-diffusion system modeled by N coupled Nagumo equations. We develop an asymptotic method to describe the phenomenon of Propagation Failure. The Nagumo model depends on two parameters: the coupling constant d and the bistability parameter a. We investigate the limit a→0 and d(a)→0 and construct traveling front solutions. We obtain the critical coupling constant d = d ∗ (a) above which Propagation is possible and determine the Propagation speed c = c(d) if d>d ∗ . We investigate two different cases for the initiation of a propagating front solution. Case 1 considers a uniform steady state distribution. A propagating front appears as the result of a fixed boundary condition. Case 2 also considers a uniform steady state distribution but a propagating front appears as the result of a localized perturbation.
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Propagation Failure in arrays of coupled bistable chemical reactors
The Journal of Physical Chemistry, 1992Co-Authors: J P Laplante, Thomas ErneuxAbstract:We consider a one-dimensional array of coupled stirred tank reactors. Each reactor operates with the bistable chlorite-iodide reaction. The reaction admits two stable steady sites (A and B). At time zero, all reactors are at steady state A except the first reactor which is at steady state B. Provided the coupling (exchange rate) between each reactor is sufficiently large, a propagating wave joining A to B is initiated. We determine the speed of the front and show that it fails to propagate if the exchange rate is below a nonzero value. In addition, we investigate the time history of the front and identify three distinct stages. First, we note a boundary layer regime corresponding to the end of the front and the approach to the final uniform steady state. We explain all three stages by analyzing a simple model
Saverio Morfu - One of the best experts on this subject based on the ideXlab platform.
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Propagation Failure in discrete bistable reaction diffusion systems theory and experiments
Physical Review E, 2001Co-Authors: Jeanchristophe Comte, Saverio Morfu, Patrick MarquieAbstract:Wave front Propagation Failure is investigated in discrete bistable reaction-diffusion systems. We present a theoretical approach including dissipative effects and leading to an analytical expression of the critical coupling beyond which front Propagation can occur as a function of the nonlinearity threshold parameter. Our theoretical predictions are confirmed by numerical simulations and experimental results on an equivalent electrical diffusive lattice.
Nicola A. Maffiuletti - One of the best experts on this subject based on the ideXlab platform.
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Central and Peripheral Fatigue after Electrostimulation-Induced Resistance Exercise
2014Co-Authors: Delphine Boerio, Marc Jubeau, Raphael Zory, Nicola A. MaffiulettiAbstract:induced by a typical session of electromyostimulation (EMS) of the triceps surae muscle. Methods: A series of neuromuscular tests including voluntary and electrically evoked contractions were performed before and immediately after 13 min of EMS (75 Hz) in 10 healthy individuals. Results: Maximal voluntary contraction torque of the plantar flexor muscles significantly decreased (9.4%; P 0.001) after EMS, and this was accompanied by an impairment of central activation, as attested by twitch interpolation results (P 0.05), whereas soleus maximal Hoffmann reflex and tibialis anterior coactivation did not change significantly. Contractile properties associated with paired stimuli and maximal M-wave amplitude for both soleus and medial gastrocnemius muscles (9.4 and 38.7%, respectively) were significantly affected by EMS (P 0.05), whereas postactivation potentiation did not change. Conclusion: A single bout of EMS resulted in fatigue attributable to both central and peripheral factors. The most obvious alteration in the function of the central nervous system is a decrease in the quantity of the neural drive to muscle from the supraspinal centers. On the other hand, neuromuscular Propagation Failure was more evident for the muscle with the higher percentage of Type II fibers. Key Words: TRICEPS SURAE, TORQUE, H REFLEX, EMG ACTIVITY, ACTIVATION LEVEL Fatigue is defined as any exercise-induced reduction inforce generating capacity of a muscle (4), and canoriginate from peripheral and/or central factors. Pe-ripheral fatigue is typically associated with alterations at or below the neuromuscular junction, whereas central fatigue is defined as a progressive reduction in voluntary activatio
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Central and peripheral fatigue after electrostimulation-induced resistance exercise
Medicine and Science in Sports and Exercise, 2005Co-Authors: Delphine Boerio, Marc Jubeau, Raphael Zory, Nicola A. MaffiulettiAbstract:PURPOSE: To investigate central and peripheral fatigue induced by a typical session of electromyostimulation (EMS) of the triceps surae muscle. METHODS: A series of neuromuscular tests including voluntary and electrically evoked contractions were performed before and immediately after 13 min of EMS (75 Hz) in 10 healthy individuals. RESULTS: Maximal voluntary contraction torque of the plantar flexor muscles significantly decreased (-9.4%; P < 0.001) after EMS, and this was accompanied by an impairment of central activation, as attested by twitch interpolation results (P < 0.05), whereas soleus maximal Hoffmann reflex and tibialis anterior coactivation did not change significantly. Contractile properties associated with paired stimuli and maximal M-wave amplitude for both soleus and medial gastrocnemius muscles (-9.4 and -38.7%, respectively) were significantly affected by EMS (P < 0.05), whereas postactivation potentiation did not change. CONCLUSION: A single bout of EMS resulted in fatigue attributable to both central and peripheral factors. The most obvious alteration in the function of the central nervous system is a decrease in the quantity of the neural drive to muscle from the supraspinal centers. On the other hand, neuromuscular Propagation Failure was more evident for the muscle with the higher percentage of Type II fibers.
