annulus

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annulus

[′an·yə·ləs]
(anatomy)
Any ringlike anatomical part.
(botany)
An elastic ring of cells between the operculum and the mouth of the capsule in mosses.
A line of cells, partly or entirely surrounding the sporangium in ferns, which constricts, thus causing rupture of the sporangium to release spores.
A whorl resembling a calyx at the base of the strobilus in certain horsetails.
(mathematics)
The ringlike figure that lies between two concentric circles.
(mycology)
A ring of tissue representing the remnant of the veil around the stipe of some agarics.
References in periodicals archive ?
David, "Axial Couette-Poiseuille Flow of Power-Law Viscoplastic Fluids in Concentric Annuli," J.
Internal growth annuli were defined as areas of discontinuity of the prismatic layer that extended from the nacreous layer to the periostracum (Fig.
12 and 13, for the thin and thick annuli, respectively.
Otoliths for which there was agreement in the annuli count were assigned a final margin category if any two of the margin categories from multiple readings for a single otolith were the same.
Majumder, "Melting of Phase Change Material in a Concentric Horizontal Annuli of Arbitrary Cross Section," Appl.
Drill Cuttings Transport by Non-Newtonian Drilling Fluids Through Inclined, Eccentric Annuli," PhD dissertation, U.
Fin ray annuli, each defined as a single pair of opaque and translucent bands completely encircling the cross-section hemisphere without partial and split checks (Ehrhardt et al.
In the otoliths of young Pacific cod (under 6 years), there is a tendency for sub-annual marks (also known as "checks") to be very dark and evenly spaced, making them difficult to distinguish from annuli.
This fraction was added to the number of annuli read in the otoliths to avoid any potential bias in growth estimates due to differences in sampling date (Gordoa and Moll, 1997).
Further variation exists on exactly which combination of annuli to use.
Age was esimated as the annulus count because permit both spawn and form annuli at about the same time of year.
We counted annuli and assessed edge condition in sagittal otoliths of 3791 red snapper collected from the northern Gulf of Mexico off Louisiana during the periods from 1989 to 1992 and from 1995 to 1998.