apex

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Related to root apex: root morphology

apex

1. the highest point; vertex
2. Astronomy the point on the celestial sphere, lying in the constellation Hercules, towards which the sun appears to move at a velocity of 20 kilometres per second relative to the nearest stars
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

apex

1. (solar apex) The point on the celestial sphere toward which the Sun and the Solar System are moving relative to the stars in our vicinity. The apex lies in the constellation Hercules at a position RA 18h, dec +30°, close to the star Vega. The point diametrically opposite to the direction of this relative solar motion is the antapex (or solar antapex); it lies in the constellation Columba. The position of the apex can be determined from an analysis of the proper motions, radial velocities, and parallaxes of stars, based on the assumption that solar motion is equal and opposite to the group motion of stars. The velocity of this motion has been calculated as about 19.5 km s–1 with respect to the local standard of rest, when all available information on proper motion and radial velocity is used. The value is lower when only the stars in the Sun's immediate neighborhood are considered. Solar motion produces the secular parallax of stars.
2. The point on the celestial sphere toward which the Earth appears to be moving, at a given time, as a result of its orbital motion around the Sun.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006

Apex

The highest point, peak, or tip of any structure.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved

apex

[′ā‚peks]
(anatomy)
The upper portion of a lung extending into the root.
The pointed end of the heart.
The tip of the root of a tooth.
(botany)
The pointed tip of a leaf.
(engineering)
In architecture or construction, the highest point, peak, or tip of any structure.
(geology)
The part of a mineral vein nearest the surface of the earth.
(mathematics)
The vertex of a triangle opposite the side which is regarded as the base.
The vertex of a cone or pyramid.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

apex

In architecture or construction, the highest point, peak, or tip of any structure.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

apex

apexclick for a larger image
Top-center portion of a parachute canopy where suspension lines cross.
An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved
References in periodicals archive ?
A de novo synthesis citrate transporter, Vigna umbellata multidrug and toxic compound extrusion, implicates in Al-activated citrate efflux in rice bean (Vigna umbellata) root apex. Plant, Cell & Environment, Oxford, v.
In the present study all the accessory canals in both maxillary and mandibular canines were found in the apical one-third region within 2 mm from the root apex (Table 3).
In vitro evaluation of apical sealing in root apex treated with demineralization agents and retrofiled with mineral trioxide aggregate through marginal dye leakage.
distributed over the entire surface of the root apex. However,
(1999) showed that high concentrations of Al (250 [micro]M; 80 min treatment) significantly decreased POD activity in the first 6 mm of the root apex in the sensitive inbred line of maize but not the tolerant inbred line.
Staining with hematoxylin indicated that Al was located in the root apex of both Al-sensitive Soft Touch and Al-tolerant Cayenne (Fig.
One exception is exclusion of Al from the root tip, achieved by Al-induced release of organic acids that chelate Al and thus prevent its entry into the root apex (Miyasaka et al., 1991; Delhaize et al., 1993b; Pellet et al., 1995; Ryan et al., 1995a, b).
On radiographic examination, the maxillary left central incisor showed an immature root apex with a diameter of >2.0 mm.
Key Words: Primary teeth, Pulp therapy, Root Apex Locator, Vital teeth, Necrotic teeth.
The action of microorganisms, enzymes, toxins, metabolic products, cellular constituents and inflammatory mediators, associated with the degree of virulence and host responses, determine the different pathologies that reach the root apex. (2,6) Symptomatic apical periodontitis is associated with very virulent microorganisms and/or less resistant host and with weakened defenses; asymptomatic apical periodontitis is related to the microorganisms of low virulence and/or to a more resistant host.