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  2. Perceptual control theory - Wikipedia

    en.wikipedia.org/wiki/Perceptual_control_theory

    Perceptual control theory (PCT) is a model of behavior based on the properties of negative feedback control loops. A control loop maintains a sensed variable at or near a reference value by means of the effects of its outputs upon that variable, as mediated by physical properties of the environment.

  3. PDF/A - Wikipedia

    en.wikipedia.org/wiki/PDF/A

    PDF is a standard for encoding documents in an "as printed" form that is portable between systems. However, the suitability of a PDF file for archival preservation depends on options chosen when the PDF is created: most notably, whether to embed the necessary fonts for rendering the document; whether to use encryption; and whether to preserve additional information from the original document ...

  4. Negative selection (natural selection) - Wikipedia

    en.wikipedia.org/wiki/Negative_selection...

    In natural selection, negative selection [1] or purifying selection is the selective removal of alleles that are deleterious. This can result in stabilising selection through the purging of deleterious genetic polymorphisms that arise through random mutations.

  5. Thrombin - Wikipedia

    en.wikipedia.org/wiki/Thrombin

    2.3 Negative feedback. 3 Structure. 4 Gene. ... Download as PDF; Printable version; ... from a level of around 0.5 units/mL 1 day after birth, to a level of around 0. ...

  6. Hypothalamic–pituitary–thyroid axis - Wikipedia

    en.wikipedia.org/wiki/Hypothalamic–pituitary...

    Thyrotropic feedback control on a more detailed and quantitative level. [3] Thyroid homeostasis results from a multi-loop feedback system that is found in virtually all higher vertebrates. Proper function of thyrotropic feedback control is indispensable for growth, differentiation, reproduction and intelligence.

  7. Attenuator (genetics) - Wikipedia

    en.wikipedia.org/wiki/Attenuator_(genetics)

    Attenuation is a second mechanism of negative feedback in the trp operon. While the TrpR repressor decreases transcription by a factor of 70, attenuation can further decrease it by a factor of 10, thus allowing accumulated repression of about 700-fold. Attenuation is made possible by the fact that in prokaryotes (which have no nucleus), the ...

  8. Catabolism - Wikipedia

    en.wikipedia.org/wiki/Catabolism

    Released from alpha cells in the pancreas either when starving or when the body needs to generate additional energy; it stimulates the breakdown of glycogen in the liver to increase blood glucose levels; its effect is the opposite of insulin; glucagon and insulin are a part of a negative-feedback system that stabilizes blood glucose levels ...

  9. Synaptic fatigue - Wikipedia

    en.wikipedia.org/wiki/Synaptic_fatigue

    It is thought to be a form of negative feedback in order to physiologically control particular forms of nervous system activity. [1] It is caused by a temporary depletion of synaptic vesicles that house neurotransmitters in the synapse, generally produced by persistent high frequency neuronal stimulation. The neurotransmitters are released by ...