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Autowave Reverberator
In the theory of autowave phenomena an autowave reverberator is an autowave vortex in a two-dimensional active medium. A reverberator appears a result of a rupture in the front of a plane autowave. Such a rupture may occur, for example, via collision of the front with a nonexcitable obstacle. In this case, depending on the conditions, either of two phenomena may arise: a ''spiral wave'', which rotates around the obstacle, or an ''autowave reverberator'' which rotates with its tip free. Introduction The ''reverberator'' was one of the first autowave solutions, researchers found, and, because of this historical context, it remains by nowadays the most studied autowave object. Up until the late 20th century, the term "''auto-wave reverberator''" was used very active and widely in the scientific literature, written by soviet authors, because of active developing these investigations in USSR (for more details, see "A brief history of autowave researches" in Autowave). And, inasmuc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autowave
Autowaves are self-supporting non-linear waves in active media (i.e. those that provide distributed energy sources). The term is generally used in processes where the waves carry relatively low energy, which is necessary for synchronization or switching the active medium. Introduction Relevance and significance In 1980, the Soviet scientists G.R. Ivanitsky, V.I. Krinsky, A.N. Zaikin, A.M. Zhabotinsky, B.P. Belousov became winners of the highest state award of the USSR, Lenin Prize "''for the discovery of a new class of autowave processes and the study of them in disturbance of stability of the distributed excitable systems''." A brief history of autowave researches The first who studied actively the self-oscillations was Academician AA Andronov, and the term "''auto-oscillations''" in Russian terminology was introduced by AA Andronov in 1928. His followers from Lobachevsky University further contributed greatly to the development of ''autowave theory''. The s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bifurcation Memory
Bifurcation memory is a generalized name for some specific features of the behaviour of the dynamical system near the bifurcation. General information The phenomenon is known also under the names of "''stability loss delay for dynamical bifurcations''" and "''ghost attractor''". The essence of the effect of bifurcation memory lies in the appearance of a special type of transition process. An ''ordinary transition process'' is characterized by asymptotic approach of the dynamical system from the state defined by its initial conditions to the state corresponding to its stable stationary regime in the basin of attraction of which the system found itself. However, near the bifurcation boundary can be observed two types of transition processes: passing through the place of the vanished stationary regime, the dynamic system slows down its asymptotic motion temporarily, "as if recollecting the defunct orbit", with the number of revolutions of the phase trajectory in this area of bif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlinear Systems
In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists because most systems are inherently nonlinear in nature. Nonlinear dynamical systems, describing changes in variables over time, may appear chaotic, unpredictable, or counterintuitive, contrasting with much simpler linear systems. Typically, the behavior of a nonlinear system is described in mathematics by a nonlinear system of equations, which is a set of simultaneous equations in which the unknowns (or the unknown functions in the case of differential equations) appear as variables of a polynomial of degree higher than one or in the argument of a function which is not a polynomial of degree one. In other words, in a nonlinear system of equations, the equation(s) to be solved cannot be written as a linear combination of the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biomedical Cybernetics
Biomedical cybernetics investigates signal processing, decision making and control structures in living organisms. Applications of this research field are in biology, ecology and health sciences. Fields * Biological cybernetics * Medical cybernetics Methods * Connectionism * Decision theory * Information theory * Systeomics * Systems theory See also * Cybernetics * Prosthetics * List of biomedical cybernetics software References * * *Kitano, H. (Hrsg.) (2001). Foundations of Systems Biology. Cambridge (Massachusetts), London, MIT Press The MIT Press is a university press affiliated with the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts (United States). It was established in 1962. History The MIT Press traces its origins back to 1926 when MIT publish ..., . * External links *ResearchGate topic on biomedical cybernetics Cybernetics {{Systemstheory-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Science
Computational science, also known as scientific computing or scientific computation (SC), is a field in mathematics that uses advanced computing capabilities to understand and solve complex problems. It is an area of science that spans many disciplines, but at its core, it involves the development of models and simulations to understand natural systems. * Algorithms ( numerical and non-numerical): mathematical models, computational models, and computer simulations developed to solve science (e.g., biological, physical, and social), engineering, and humanities problems * Computer hardware that develops and optimizes the advanced system hardware, firmware, networking, and data management components needed to solve computationally demanding problems * The computing infrastructure that supports both the science and engineering problem solving and the developmental computer and information science In practical use, it is typically the application of computer simulation and other fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biophysics
Biophysics is an interdisciplinary science that applies approaches and methods traditionally used in physics to study biological phenomena. Biophysics covers all scales of biological organization, from molecular to organismic and populations. Biophysical research shares significant overlap with biochemistry, molecular biology, physical chemistry, physiology, nanotechnology, bioengineering, computational biology, biomechanics, developmental biology and systems biology. The term ''biophysics'' was originally introduced by Karl Pearson in 1892.Roland Glaser. Biophysics: An Introduction'. Springer; 23 April 2012. . The term ''biophysics'' is also regularly used in academia to indicate the study of the physical quantities (e.g. electric current, temperature, stress, entropy) in biological systems. Other biological sciences also perform research on the biophysical properties of living organisms including molecular biology, cell biology, chemical biology, and biochemistry. Overview ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (such as with exercise) or abnormal (such as with electrical problems within the heart). Complications Tachycardia can lead to fainting. When the rate of blood flow becomes too rapid, or fast blood flow passes on damaged endothelium, it increases the friction within vessels resulting in turbulence and other disturbances. According to the Virchow's triad, this is one of the three conditions that can lead to thrombosis (i.e., blood clots within vessels). Causes Some causes of tachycardia include: * Adrenergic storm * Anaemia * Anxiety * Atrial fibrillation * Atrial flutter * Atrial tachycardia * Atrioventricular reentrant tachycardia * AV nodal reentrant tachycardia * Brugada syndrome * Circulatory shock and its various causes ( obstr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiology
Cardiology () is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery. Specializations All cardiologists study the disorders of the heart, but the study of adult and child heart disorders each require different training pathways. Therefore, an adult cardiologist (often simply called "cardiologist") is inadequately trained to take care of children, and pediatric cardiologists are not trained to treat adult heart disease. Surgical aspects are not included in cardiology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refractory Period (physiology)
Refractoriness is the fundamental property of any object of autowave nature (especially excitable medium) not to respond on stimuli, if the object stays in the specific ''refractory state''. In common sense, refractory period is the characteristic recovery time, a period that is associated with the motion of the image point on the left branch of the isocline \dot = 0 (for more details, see also Reaction–diffusion and Parabolic partial differential equation). In physiology, a refractory period is a period of time during which an organ or cell is incapable of repeating a particular action, or (more precisely) the amount of time it takes for an excitable membrane to be ready for a second stimulus once it returns to its resting state following an excitation. It most commonly refers to electrically excitable muscle cells or neurons. Absolute refractory period corresponds to depolarization and repolarization, whereas relative refractory period corresponds to hyperpolarization ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vortex
In fluid dynamics, a vortex ( : vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in the wake of a boat, and the winds surrounding a tropical cyclone, tornado or dust devil. Vortices are a major component of turbulent flow. The distribution of velocity, vorticity (the curl of the flow velocity), as well as the concept of circulation are used to characterise vortices. In most vortices, the fluid flow velocity is greatest next to its axis and decreases in inverse proportion to the distance from the axis. In the absence of external forces, viscous friction within the fluid tends to organise the flow into a collection of irrotational vortices, possibly superimposed to larger-scale flows, including larger-scale vortices. Once formed, vortices can move, stretch, twist, and interact in complex ways. A moving vortex carries s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
