Search results
Results from the WOW.Com Content Network
Audio feedback (also known as acoustic feedback, simply as feedback, or the Larsen effect) is a special kind of positive feedback which occurs when a sound loop exists between an audio input (for example, a microphone or guitar pickup) and an audio output (for example, a loudly-amplified loudspeaker).
An example is a system in which a protein P that is a product of gene G "positively regulates its own production by binding to a regulatory element of the gene coding for it," [14] and the protein gets used or lost at a rate that increases as its concentration increases. This feedback loop creates two possible states "on" and "off".
The Hodgkin cycle represents a positive feedback loop in which an initial membrane depolarization leads to uncontrolled deflection of the membrane potential to near V Na. The initial depolarization must reach or surpass a certain threshold in order to activate voltage-gated Na + channels .
The activation of Mos leads to a positive feedback loop and therefore acts as “toggle switch” to create the all-or-nothing entrance into mitosis. Schematic of the MAPK signaling cascade. This feedback loop was first found by showing that MAPK-P (phosphorylated MAPK) concentrations increased in response to increasing levels of progesterone. [24]
Because all brain areas are bidirectionally coupled, these connections between brain areas form feedback loops. Positive feedback loops tend to cause oscillatory activity where frequency is inversely related to the delay time. An example of such a feedback loop is the connections between the thalamus and cortex – the thalamocortical radiations.
One of the most common forms of biological oscillation is genetic oscillation, which can take place when a transcription factor binds and represses its own promoter.This type of regulatory system is able to successfully describe the NFkB-IkB and p53-Mdm52 biological oscillating systems.
This is an example of a positive feedback loop. The ability of these channels to assume a closed-inactivated state causes the refractory period and is critical for the propagation of action potentials down an axon .
An effector is the target acted on, to bring about the change back to the normal state. At the cellular level, effectors include nuclear receptors that bring about changes in gene expression through up-regulation or down-regulation and act in negative feedback mechanisms. An example of this is in the control of bile acids in the liver. [4]