The Experts below are selected from a list of 61713 Experts worldwide ranked by ideXlab platform
Kenneth Showalter - One of the best experts on this subject based on the ideXlab platform.
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Wave front interaction model of stabilized Propagating Wave segments
Physical Review Letters, 2005Co-Authors: V S Zykov, Kenneth ShowalterAbstract:A Wave front interaction model is developed to describe the relationship between excitability and the size and shape of stabilized Wave segments in a broad class of weakly excitable media. These Wave segments of finite size are unstable but can be stabilized by feedback to the medium excitability; they define a separatrix between spiral Wave behavior and contracting Wave segments. Unbounded Wave segments (critical fingers) lie on the asymptote of this separatrix, defining the boundary between excitable and subexcitable media. The model predictions are compared with results from numerical simulations.
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Feedback stabilization of unstable Propagating Waves.
Physical review. E Statistical nonlinear and soft matter physics, 2002Co-Authors: Eugene Mihaliuk, Tatsunari Sakurai, Florin Chirila, Kenneth ShowalterAbstract:Propagating Wave segments are stabilized to a constant size and shape by applying negative feedback from the measured Wave area to the excitability of the medium. The locus of steady-state Wave size as a function of excitability defines the perturbation threshold for the initiation of spiral Waves. This locus also defines the excitability boundary for spiral Wave behavior in active media.
Katsushige Sato - One of the best experts on this subject based on the ideXlab platform.
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optical imaging of the spontaneous depolarization Wave in the mouse embryo origins and pharmacological nature
Annals of the New York Academy of Sciences, 2013Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we revealed previously in the chick and rat embryos that this correlated activity is a widely Propagating Wave of neural depolarization, which we termed the depolarization Wave. One important consideration is whether a depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the depolarization Wave in the mouse embryo by summarizing spatiotemporal characteristics and pharmacological natures of the widely Propagating Wave activity. The findings show that a synchronized Wave with common characteristics is expressed in different species, suggesting its fundamental roles in neural development.
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spontaneous depolarization Wave in the mouse embryo origin and large scale propagation over the cns identified with voltage sensitive dye imaging
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we have revealed previously that this correlated activity is a widely Propagating Wave of neural depolarization, which we termed the depolarization Wave. We have observed in the chick and rat embryos that the activity spread over an extensive region of the CNS, including the spinal cord, hindbrain, cerebellum, midbrain and forebrain. One important consideration is whether a depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the depolarization Wave in the mouse embryo by showing that the widely Propagating Wave appeared independently of the localized spontaneous activity detected previously with Ca(2+) imaging. Furthermore, we mapped the origin of the depolarization Wave and revealed that the Wave generator moved from the rostral spinal cord to the caudal cord as development proceeded, and was later replaced with mature rhythmogenerators. The present study, together with an accompanying paper that describes pharmacological properties of the mouse depolarization Wave, shows that a synchronized Wave with common characteristics is expressed in different species, suggesting fundamental roles in neural development.
Yoko Momosesato - One of the best experts on this subject based on the ideXlab platform.
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optical imaging of the spontaneous depolarization Wave in the mouse embryo origins and pharmacological nature
Annals of the New York Academy of Sciences, 2013Co-Authors: Yoko Momosesato, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we revealed previously in the chick and rat embryos that this correlated activity is a widely Propagating Wave of neural depolarization, which we termed the depolarization Wave. One important consideration is whether a depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the depolarization Wave in the mouse embryo by summarizing spatiotemporal characteristics and pharmacological natures of the widely Propagating Wave activity. The findings show that a synchronized Wave with common characteristics is expressed in different species, suggesting its fundamental roles in neural development.
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spontaneous depolarization Wave in the mouse embryo origin and large scale propagation over the cns identified with voltage sensitive dye imaging
European Journal of Neuroscience, 2012Co-Authors: Yoko Momosesato, Tomoharu Nakamori, Katsushige SatoAbstract:: Spontaneous embryonic movements, called embryonic motility, are produced by correlated spontaneous activity in the cranial and spinal nerves, which is driven by brainstem and spinal networks. Using optical imaging with a voltage-sensitive dye, we have revealed previously that this correlated activity is a widely Propagating Wave of neural depolarization, which we termed the depolarization Wave. We have observed in the chick and rat embryos that the activity spread over an extensive region of the CNS, including the spinal cord, hindbrain, cerebellum, midbrain and forebrain. One important consideration is whether a depolarization Wave with similar characteristics occurs in other species, especially in different mammals. Here, we provide evidence for the existence of the depolarization Wave in the mouse embryo by showing that the widely Propagating Wave appeared independently of the localized spontaneous activity detected previously with Ca(2+) imaging. Furthermore, we mapped the origin of the depolarization Wave and revealed that the Wave generator moved from the rostral spinal cord to the caudal cord as development proceeded, and was later replaced with mature rhythmogenerators. The present study, together with an accompanying paper that describes pharmacological properties of the mouse depolarization Wave, shows that a synchronized Wave with common characteristics is expressed in different species, suggesting fundamental roles in neural development.
F P Keenan - One of the best experts on this subject based on the ideXlab platform.
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Propagating Wave phenomena detected in observations and simulations of the lower solar atmosphere
The Astrophysical Journal, 2012Co-Authors: D B Jess, Sergiy Shelyag, Mihalis Mathioudakis, Peter H Keys, D J Christian, F P KeenanAbstract:We present high-cadence observations and simulations of the solar photosphere, obtained using the Rapid Oscillations in the Solar Atmosphere imaging system and the MuRAM magnetohydrodynamic (MHD) code, respectively. Each data set demonstrates a wealth of magnetoacoustic oscillatory behavior, visible as periodic intensity fluctuations with periods in the range 110-600 s. Almost no Propagating Waves with periods less than 140 s and 110 s are detected in the observational and simulated data sets, respectively. High concentrations of power are found in highly magnetized regions, such as magnetic bright points and intergranular lanes. Radiative diagnostics of the photospheric simulations replicate our observational results, confirming that the current breed of MHD simulations are able to accurately represent the lower solar atmosphere. All observed oscillations are generated as a result of naturally occurring magnetoconvective processes, with no specific input driver present. Using contribution functions extracted from our numerical simulations, we estimate minimum G-band and 4170 A continuum formation heights of 100 km and 25 km, respectively. Detected magnetoacoustic oscillations exhibit a dominant phase delay of –8° between the G-band and 4170 A continuum observations, suggesting the presence of upwardly Propagating Waves. More than 73% of MBPs (73% from observations and 96% from simulations) display upwardly Propagating Wave phenomena, suggesting the abundant nature of oscillatory behavior detected higher in the solar atmosphere may be traced back to magnetoconvective processes occurring in the upper layers of the Sun's convection zone.
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Propagating Wave phenomena detected in observations and simulations of the lower solar atmosphere
arXiv: Solar and Stellar Astrophysics, 2012Co-Authors: D B Jess, Sergiy Shelyag, Mihalis Mathioudakis, Peter H Keys, D J Christian, F P KeenanAbstract:We present high-cadence observations and simulations of the solar photosphere, obtained using the Rapid Oscillations in the Solar Atmosphere imaging system and the MuRAM magneto-hydrodynamic code, respectively. Each dataset demonstrates a wealth of magneto-acoustic oscillatory behaviour, visible as periodic intensity fluctuations with periods in the range 110-600 s. Almost no Propagating Waves with periods less than 140s and 110s are detected in the observational and simulated datasets, respectively. High concentrations of power are found in highly magnetised regions, such as magnetic bright points and intergranular lanes. Radiative diagnostics of the photospheric simulations replicate our observational results, confirming that the current breed of magneto-hydrodynamic simulations are able to accurately represent the lower solar atmosphere. All observed oscillations are generated as a result of naturally occurring magnetoconvective processes, with no specific input driver present. Using contribution functions extracted from our numerical simulations, we estimate minimum G-band and 4170 Angstrom continuum formation heights of 100 km and 25 km, respectively. Detected magneto-acoustic oscillations exhibit a dominant phase delay of -8 degrees between the G-band and 4170 Angstrom continuum observations, suggesting the presence of upwardly Propagating Waves. More than 73% of MBPs (73% from observations, 96% from simulations) display upwardly Propagating Wave phenomena, suggesting the abundant nature of oscillatory behaviour detected higher in the solar atmosphere may be traced back to magnetoconvective processes occurring in the upper layers of the Sun's convection zone.
V S Zykov - One of the best experts on this subject based on the ideXlab platform.
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Wave front interaction model of stabilized Propagating Wave segments
Physical Review Letters, 2005Co-Authors: V S Zykov, Kenneth ShowalterAbstract:A Wave front interaction model is developed to describe the relationship between excitability and the size and shape of stabilized Wave segments in a broad class of weakly excitable media. These Wave segments of finite size are unstable but can be stabilized by feedback to the medium excitability; they define a separatrix between spiral Wave behavior and contracting Wave segments. Unbounded Wave segments (critical fingers) lie on the asymptote of this separatrix, defining the boundary between excitable and subexcitable media. The model predictions are compared with results from numerical simulations.
