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Related to Branchial arches: Branchial cyst, branchial fistula

ARCH

Autoregressive Conditional Heteroskedasticity

A statistical measure of the average error between a best fit line and actual data that uses past data to predict future performance. General Autoaggressive Conditional Heteroskedasticity is the most common way of doing this. See also: Fractal Distribution.
References in periodicals archive ?
As this is an anomaly of the first and second branchial arches, most alterations are associated with structures developed from these arches, (28) presenting wide phenotypic variation.
aureus continued even after surgical removal of the gill rakers and microbranchiospines, indicating that the surfaces of the branchial arches themselves are involved in the generation of inertial lift forces (Smith and Sanderson, 2007).
For clarity of presentation, we have depicted the elements that make up the braincase as the neurocranial cartilage [ILLUSTRATION FOR FIGURE 4E-H OMITTED], whereas those elements derived from the seven pharyngeal arches (the mandibular, hyoid, and five branchial arches) and from the pectoral girdle are presented as the pharyngeal-pectoral cartilage [ILLUSTRATION FOR FIGURE 4I-L OMITTED].
It results from an aberrant development of the 1st and 2nd branchial arches. It has an incidence of approximately 1 in 5600, more common among males with a ratio of 2:1 and also common among whites.
They arise as a result of an abnormal development of the branchial arches and their corresponding ectoderm-lined branchial clefts.
However, in general, the branchial apparatus structures develop between the 4th and 6th week of gestation and consist of 6 pairs of mesodermal branchial arches separated by 5 paired endodermal pharyngeal pouches internally and 5 paired ectodermal branchial clefts externally.
Other proposed theories are mesodermal dysplasia of Ist and IInd branchial arches. Benzodiazepenes, coccaine and misoprostol has also been implicated as the cause of Mobius syndrome.
(1) Those 2 cases were associated with Goldenhar syndrome, a hereditary disorder characterized by several abnormalities that affect the first and the second branchial arches. In this article, the author presents a new and novel case of this unusual malformation.
It results from failure of fusion of mandibular and maxillary processes of the first branchial arch (1) and so Tessier cleft 7 is also associated with anomalies of the structures arising from first and second branchial arches. The reported incidence varies from 1 in 100 to 1 in 300 of all facial clefts (2).
At the fifth week of fetal development, the first and second branchial arches of the pharyngeal wall undergo a downward proliferation and meet the epicardial ridge, thereby closing the communication of the second, third, and fourth clefts with the exterior surface of the neck.
The dlx homobox gene codes for regional specification of branchial arches and mutation in these genes is associated with the aberrant branchial arches.