External stimuli

Information processing. Stimuli external to a cell, such as hormone signals or light intensity, are detected by specific proteins that transfer a signal to the interior of the cell. A well-characterized example is the visual protein rhodopsin, located in membranes of retinal cells. 

External stimulus flow meters are generally electrical in nature. These devices derive their signal from the interaction of the fluid motion with some external stimulus such as a magnetic field, laser energy, an ultrasonic beam, or a radioactive tracer. 

Referring to Fig. 9, the effect of the shear is to catalyze the reaction, presumably through suppression of the interfacial barrier by stretching the flow. The latter is believed to reduce the diffusion path, promoting the reaction rate, and hence the rate of increase in the viscosity. A similar effect is produced with temperature as a parameter, which also augments the reaction rate. The modified reaction rate constant in case of any external stimulus or perturbation acting on the system may be computed from the scalar K, where ... 

AKAPs are a diverse family of about 75 scaffolding proteins. They are defined by the presence of a structurally conserved protein kinase A (PKA)-binding domain. AKAPs tether PKA and other signalling proteins to cellular compartments and thereby limit and integrate cellular signalling processes at specific sites. This compartmentalization of signalling by AKAPs contributes to the specificity of a cellular response to a given external stimulus (e.g. a particular hormone or neurotransmitter). 

The successful initiation of high energy material, which would include an entire variety of substances such as BlkPdr, smokeless or NC type powder, pyrot or display powder, and HE material, is accomplished by the application of a small external stimulus, provided by a suitable source of energy... 

Cytokines. Nonspecific water-soluble glycoproteins with a short half-life produced and secreted abruptly by white blood cells in response to an external stimulus, and which act as chemical messengers between cells. 

Tropism. Response/reaction of an organism to an external stimulus shown as movement. 

By external stimulus at the plate electrode, migration of the ions in the solvent is induced, which changes the spatial concentration and so the local course of reactions [68]. By this means, weak electrical fields change the propagation velocity of the reaction zone through the capillary strong electrical fields ( supercritical ) further affect the global feature of the reaction in the capillary. 

By external stimulus at the wire electrode, a reaction is initiated which propagates from the center in all directions evenly and so forms an expanding ring [68]. 

For the catalytic oxidation of malonic acid by bromate (the Belousov-Zhabotinskii reaction), fimdamental studies on the interplay of flow and reaction were made. By means of capillary-flow investigations, spatio-temporal concentration patterns were monitored which stem from the interaction of a specific complex reaction and transport of reaction species by molecular diffusion [68]. One prominent class of these patterns is propagating reaction fronts. By external electrical stimulus, electromigration of ionic species can be investigated. 

Several methods exist for measuring the electron work functions of metals. In all these methods one determines the level of an external stimulus (light, heat, etc.) required to extract electrons from the metal. 

The steady state is disturbed and the system exhibits transient behavior when at least one of its parameters is altered under an external stimulus (perturbation). Transitory processes that adjust the other parameters set in (response) and at the end produce a new steady state. The time of adjustment (transition time, relaxation time) is an important characteristic of the system. 

The velocities of the propagation of electrical signals that have values from 0.0005 to 40m/s are sufficiently high to facilitate rapid long-distance communication and account for the rapid response phenomena observed in plants. Both the speed of propagation and the duration of action potential depend on the type of external stimulus. 

Compared with phagocytosis, pinocytosis appears to be a universal phenomenon in all cells, including phagocytes. Unlike phagocytosis, which is mediated by the serum opsonin, pinocytosis does not require any external stimulus. Pinocytosis is divided into two types fluid-phase pinocytosis and adsorptive pinocytosis (see Fig. 3B). Fluid-phase pinocytosis is a nonspecific, continuous process, and it is believed to be useful as a general process for transporting macromolecular constructs through epithelia, some endothelia, and into various blood cells. Adsorptive pinocytosis, in... 

Davies, J. A. et al., J. Chem. Soc., Dalton Trans., 1980, 2246-2249 Extremely sensitive to thermal and mechanical shock, occasionally detonating spontaneously without external stimulus, it should only be prepared and used in solution. The solid is an extreme hazard, and the acetone-solvated complex is also explosive. 

Two terms which help define a control system are input and output. Control system input is the stimulus applied to a control system from an external source to produce a specified response from the control system. In the case of the central heating unit, the control system input is the temperature of the house as monitored by the thermostat. 

Control system input is the stimulus applied to a control system from an external source to produce a specified response from the control system. 

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