Synchronization Synchronizing wave

In everyday life a dear distinction is made between particles and waves. A particle has a well-defined mass, and its position and velocity can be accurately determined as a function of time by applying Newton s laws of motion. Waves do not have mass in the normal sense and cannot be precisely located they are best described in terms of a characteristic frequency and wavelength. Waves also have the important properly that they can interact with one another to produce interference patterns, a process known as diffraction. An example of this is shown in Figure 1.1, where interference is observed between two synchronous wave sources. When w e look at the interaction of electrons with a metal surface we find that they can be diffracted in a similar way, and it must be concluded that they, too, have wave-like properties, although they are normally... 

The local dynamics of tire systems considered tluis far has been eitlier steady or oscillatory. However, we may consider reaction-diffusion media where tire local reaction rates give rise to chaotic temporal behaviour of tire sort discussed earlier. Diffusional coupling of such local chaotic elements can lead to new types of spatio-temporal periodic and chaotic states. It is possible to find phase-synchronized states in such systems where tire amplitude varies chaotically from site to site in tire medium whilst a suitably defined phase is synclironized tliroughout tire medium 51. Such phase synclironization may play a role in layered neural networks and perceptive processes in mammals. Somewhat suriDrisingly, even when tire local dynamics is chaotic, tire system may support spiral waves... 

The Cardiac Cycle. The heart (Eig. lb) performs its function as a pump as a result of a rhythmical spread of a wave of excitation (depolarization) that excites the atrial and ventricular muscle masses to contract sequentially. Maximum pump efficiency occurs when the atrial or ventricular muscle masses contract synchronously (see Eig. 1). The wave of excitation begins with the generation of electrical impulses within the SA node and spreads through the atria. The SA node is referred to as the pacemaker of the heart and exhibits automaticity, ie, it depolarizes and repolarizes spontaneously. The wave then excites sequentially the AV node the bundle of His, ie, the penetrating portion of the AV node the bundle branches, ie, the branching portions of the AV node the terminal Purkinje fibers and finally the ventricular myocardium. After the wave of excitation depolarizes these various stmetures of the heart, repolarization occurs so that each of the stmetures is ready for the next wave of excitation. Until repolarization occurs the stmetures are said to be refractory to excitation. During repolarization of the atria and ventricles, the muscles relax, allowing the chambers of the heart to fill with blood that is to be expelled with the next wave of excitation and resultant contraction. This process repeats itself 60—100 times or beats per minute... 

The pay-off roll is unwound by the tension of the sheet, caused by the speed of the recoiler at the finishing line and the bridles positioned at different locations. The pay-off roll motors therefore operate in a regenerative mode and can feed-back the energy thus saved to the source of supply, if desired. This can be done by using a full-wave synchronous inverter, as shown in Figures 6.31 or 6.33. 

Nonciliated cells separate fields of ciliated epithelial cells from each other. Synchronized ciliary movement, with a beat frequency in human proximal airways under normal conditions of 8-15 EIz, propels mucus along the mucociliary escalator at a rate of up to 25 mm/min. Beat frequencies appear to slow to roughly 7 Hz in more distal airways. Cilia move in the same direction and in phase within each field but cilia in adjacent fields move in slightly different directions and are phase shifted. These beat patterns result in metachronal waves that steadily move mucus at higher velocities ( -12-18 mm/min) than would be achievable by summing the motion of individual cilia. 

Metachronal wave Synchronized ciliary movement over a relatively large... 

Figure 14-4A. Oscillogram shows variation of current to a synchronous motor driving a reciprocating compressor, The compressor is two-cylinder, horizontal, double-acting, and operates at 257 rpm. Line A is the envelope of the current wave. Difference B-C is current variation. Value B-C divided by the rated full load current is the percentage of current variation. (Used by permission Oscarson, G. L. E-M Synchronizer, 200 SYN 52, p. 11. Dresser-Rand Company.)...

Rapid eye movement sleep. Sleep stage characterized by rapid movements of the eyes and asynchronous EEG activity in the theta-frequency (5-10Hz) range. Counterpart is slow wave sleep, characterized by other electrophysiological (synchronized low frequency l-2Hz, large amplitude EEG and neuronal sharp wave-ripple oscillations) and endocrine (growth hormone surge) activities. 

Figure 1, Forcing functions for monomer (fu) and initiator (fi) feeds (a) sinusoidal (b) square-wave (c) reception vessel valve operating sequences which are synchronized with the feed policies (see Figure 2 for the location of the valves...

Press the sync control button to synchronize the defibrillator o Look for markers on R waves indicating synchronized mode o If needed, adjust monitor gain until synchronized markers... 

Intracerebroventricular infusion of CST-14 dramatically increases the amount of slow wave activity in rats, at the expense of wakefulness. The mechanism by which CST-14 enhances cortical synchronization has been established through the interaction of CST-14 with acetylcholine, a neurotransmitter known to be involved in the maintenance of cortical desynchronization. Application of acetylcholine (ACh) in the anesthetized animal increases fast activity, and this effect is blocked with the simultaneous addition of CST-14. These data suggest that CST-14 increases slow wave sleep by antagonizing the effects of ACh on cortical excitability. In addition to this mechanism, cortistatin may enhance cortical... 

FIG. 1. Phenylephrine (PE)-mediated asynchronous wave-like [Ca2+] oscillations and contraction in the rabbit inferior vena cava. (A) [Ca2+] oscillations recorded in neighbouring smooth muscle cells within the intact vessel are not synchronized between cells as they each display different frequency of oscillations. (B) Individual Ca2+ spike in PE-mediated [Ca2+]j oscillations are wave-like as different regions (1, 2 and 3) in the same ribbon-shaped VSMC experience sequential rise of [Ca2+] in time. (C) The [PE]-dependence in force generation is compared to the [PE]-dependence in the percentage recruitment of cells, the amplitude of the [Ca2+]j oscillations, the frequency of the [Ca2+]j oscillations and the apparent velocity of the recurring Ca2+ waves. (Experimental traces reproduced, with permission from Lee et al 2001.)... 

Wier Yes, we reported this in 1999 in pressurized arteries. Nifedipine produced a complete relaxation but the synchronous Ca2+ waves continued. 

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