ARCH

(redirected from branchial arch)
Also found in: Dictionary, Thesaurus, Medical, Legal, Encyclopedia, Wikipedia.
Related to branchial arch: branchial arch derivatives

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 ?
Diagnosis: Astyanax minor is distinguished from Iguacu Astyanax by combination of following characters: infraorbital 3 deep but not in contact with preopercle, leaving a narrow naked area between its border and preopercle; premaxillary external series with 4-6, usually 5 or 6 pentacuspid or heptacuspid teeth; first branchial arch 9-12, usually 10 rakers in upper branch and 13-16, usually 14 or 15 rakers in lower branch; a narrow and elongated vertical humeral bar.
Distinguished from all other congeners by the combination of the following features: anterior portion of trunk wider than deep, jaws short, snout blunt, tip of anal fin rounded in male, caudal fin elliptical to acuminate in male, pelvic-fin tip not reaching to urogenital papilla in male, dorsal-fin origin posterior to anal-fin base, dorsal-fin rays 5-6, anal-fin rays 8-10, frontal squamation S-patterned, frontal scales arranged circularly, canal preopercular short and opened, contact organs absent, longitudinal series of scales 32-34, gill rakers of first branchial arch 1 + 7, dark brown oblique bars on flank, transverse black bar through the chin, and no black spot on dorsal portion of caudal fin.
Similarly, there is an apparent modal difference in the total number of gill rakers on the first branchial arch between A.
and by the branchial spines in the inferior branch of the first branchial arch (13 to 14 for D.
The embryologic migration pattern of the second branchial arch tract originates in the tonsillar fossa, travels over third arch structures, and terminates in the middle to lower two-thirds of the lateral portion of the neck.
The orientation of teeth changes along these gill-raker tubercles, being curved towards the middle of the pharyngeal cavity in the upper part of the crown and directed at right angles to the surface of the branchial arch closer to the base.
Mouth longer, upper jaw 2 reaching to below pupil; gill opening broader, extending forward to below middle or posterior part of pupil; caudal fin without enlarged black spots; tongue tip bilobed; pectoral rays 13-15; pelvic rays unbranched; second dorsal spine longest; 13-18 elongate and pointed gill rakers on outer face of lower part of first branchial arch 2a.
In the first branchial arch the neural crest cells migrate towards the mandible, followed by their migration to the maxilla and lastly to the nasofrontal region.
Of these diverse anomalies, second branchial cleft lesions are the most common, accounting for approximately 95% of all branchial arch pathologies.
Based on imaging and the clinical history a diagnosis of branchial fistula of fourth branchial arch was made.
1) It occurs as the result of a developmental anomaly of the first branchial arch, and it may be associated with other branchial cleft abnormalities.
It develops from 3rd branchial arch and also receives contribution from the neural crest.