Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and digital video data, and is often one of the last stages of audio production to compact disc.
Hepatic porphyria. Hepatic porphyrias is a form of porphyria in which the enzyme deficiency occurs in the liver. Examples include (in order of synthesis pathway): Acute intermittent porphyria. Porphyria cutanea tarda and Hepatoerythropoietic porphyria.
Chester porphyria is a unique type of porphyria with the signs and symptoms of acute intermittent porphyria (AIP) and the biochemical defects of both AIP and variegate porphyria (VP). Chester porphyria does not conform to any of the recognized types of acute porphyria.