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

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.

Apex

The highest point, peak, or tip of any structure.

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.

apex

In architecture or construction, the highest point, peak, or tip of any structure.

apex

apexclick for a larger image
Top-center portion of a parachute canopy where suspension lines cross.
References in periodicals archive ?
75 produce ROS in the elongating zone of the root apex after only 2
It is now generally accepted that the root apex plays a major role in Al detection and response mechanisms (Delhaize and Ryan 1995; Kochian 1995; Rengel 1996).
A previous study suggested that constitutive phosphate exudation from the root apex in Atlas 66 could be a separate mechanism contributing to Al tolerance, in addition to Al-inducible malate release that was present (Pellet et al.
Fenestration of the root apex is a relatively uncommon complication of pulpal-periradicular disease.
The axial pressure (penetration resistance) on the root apex (tip) causes root deformation such as shorter and thicker roots (Bengough and Mullins, 1990; Materechera et al.
The mean linear attenuation coefficients in the mid labial region in 1 mm steps from incisor tip to the root apex were measured and calibrated against the aluminium wire standard with a linear correlation coefficient of 1.
On the basis of the hematoxylin staining results, Alp appears to confer Al tolerance by an Al exclusion mechanism acting at the root apex, which has been shown to be the site of Al phytotoxicity (Kochian, 1995).
2011) found that up to one half of the total of Al in the root apex was located in the symplasm.
Endodontic anatomy (root canal morphology) of primary teeth, in particular of molars is difficult to predict because of the resorption, shape, dimension and position of the root apex are often continuously altered.
Results showed that the proposed technique, with mesial and vertical angle variation, using the anterior tooth film holder had improved the dissociation of buccal and lingual root canals in maxillary premolars in both radiographic systems, conventional and digital, with larger root apex distances.
Scanning electron microscopy showed that the suspension-derived embryos have the morphology of a typical grass embryo including a developed scutellar region, protruding coleoptile and root apex (Fig.
As in the case of the shoot apical meristem, recent studies of the root apex consistently support the classical concept of the apical cell as the functional apical initial of the root meristem.