(n.) An opening; an open space; a gap, cleft, or chasm; a passage perforated; a hole; as, an aperture in a wall.
(n.) The diameter of the exposed part of the object glass of a telescope or other optical instrument; as, a telescope of four-inch aperture.
Example Sentences:
(1) Both apertures were repaired with great caution using individual sutures without resection of the hernial sac.
(2) By moving an electronic pen over a digitizing tablet, the subject could explore a line drawing stored in memory; on the display screen a portion of the drawing appeared to move behind a stationary aperture, in concert with the movement of the pen.
(3) The procedure consists of a Kirschner wire used as the means of traction on the remaining soft tissue of the lower lip, using the upper teeth or pyriform aperture bone as remote fixed points for tissue traction.
(4) The calibrated aperture in the bottom of each well is small enough to retain fluid contents by surface tension during monolayer growth, but also permits fluid to enter the wells when transfer plates are lowered into receptacles containing washing buffer or test sera.
(5) Acute toxicity consisted primarily of pain within the AA aperture (74%), pain outside the aperture (33%), and bladder spasm (26%) or systemic stress (25%).
(6) Latex particles, including BCR Certified Reference Material CRM 166a, have important applications for checking linearity and for calibrating aperture-impedance instruments used to determine red-cell volumes.
(7) The distance between the apertures on the screen as well as the subject's distance from the screen served as experimental parameters.
(8) When the highly crystalline core contents are suitably oriented to transmit their Bragg reflections through the objective aperture, regular fringes separated by 2-9.5 A have been visualized.
(9) Aperture size was modulated during flight on some trials in an attempt to test between these possibilities, but the results were inconclusive.
(10) When examined with the 3 mm aperture, the average resolving power of the IOLs was 81% of the diffraction limit; when examined with the 4 mm aperture, the average resolving power was 67% of the diffraction limit.
(11) Its principle consists in repairing the tissue defect resulting from the excision of the lower lip by the additional surgical removal of one or two soft tissue triangles from the region of the nasolabial fold and in achieving primarily, by means of horizontal relieving incisions at the base of the lip defect, an extension of the mouth aperture.
(12) Temporal fluctuations of stomatal aperture are important to water use efficiency.
(13) Specific microscope components and objectives are used, and the numerical apertures are adjusted such that light diffraction colors are produced to allow differentiation of the various biological entities and their habitat materials.
(14) Topographical corneal thickness changes were monitored in 10 subjects who each wore a hydrogel contact lens with a large central aperture ("donut" lens) for 6 hours.
(15) The theory is based on a three-dimensional model and the electromagnetic field is assumed to be generated by a prescribed electric field along a ring-shaped aperture.
(16) Quantitative analysis of an area 27 microns in diameter, or a total analysed volume of 1.1 microns3, was performed by using a mechanical aperture in the ion optical system.
(17) We evaluated both low- and high-power lenses and varied the input aperture size between 1, 3, and 5 mm.
(18) Subjects were asked to match the speeds of two moving random-dot patterns seen through circular apertures.
(19) However, our experience has shown us that in certain cases, there are some possibilities of aperture if we feel ourself free enough with our medical identity and if we keep silent as long as the patient is not able to hear us.
(20) The estimated doses to the third, fourth, fifth, and sixth cranial nerves was calculated at a saggital plane 13 to 15 mm from the pituitary by using computer-drawn dosimetry charts for the respective aperture size.
Spiracle
Definition:
(n.) The nostril, or one of the nostrils, of whales, porpoises, and allied animals.
(n.) One of the external openings communicating with the air tubes or tracheae of insects, myriapods, and arachnids. They are variable in number, and are usually situated on the sides of the thorax and abdomen, a pair to a segment. These openings are usually elliptical, and capable of being closed. See Illust. under Coleoptera.
(n.) A tubular orifice communicating with the gill cavity of certain ganoid and all elasmobranch fishes. It is the modified first gill cleft.
(n.) Any small aperture or vent for air or other fluid.
Example Sentences:
(1) The spiracular organ is a tube (skate) or pouch (shark) with a single pore opening into the spiracle.
(2) Therefore the interneurones have reciprocal effects on the antagonistic motoneurones of the spiracles.
(3) The spiracular organ is a lateral line derived receptor associated with the first gill cleft (spiracle).
(4) The LKIR neurons in the abdominal ganglia form efferent axons supplying the lateral cardiac nerves, spiracles, and the segmental perivisceral organs.
(5) During the process of emergence this gas moves into the exuvial space through the adult spiracles and then follows the exuvial fluid into the alimentary canal.
(6) Three Drosophila genes have been identified that are important in controlling the development of the head, two of which, empty spiracles and orthodenticle, have been cloned and shown to contain a homeobox.
(7) The second stage is sensitive to 31 degrees and coincides with the period of black rings formation on anterior spiracles in the 3rd laval instar.
(8) The final model which includes both tympana and spiracles is able to simulate both the hearing directionality and, in part, the frequency selectivity of the system.
(9) The reduced spiracles play little or no role in gill ventilation.
(10) Spiracles of insects open in high carbon dioxide tensions and close in high oxygen tensions.
(11) Rickettsiae-like structures were found in the salivary gland cells of Drosophila auraria during different larval and prepupal developmental stages, from the early 3rd instar up to 14 hr after spiracle inversion.
(12) The closer muscles of the left and the right spiracles of a thoracic segment are both innervated by two motoneurones, which spike in a variety of patterns during expiration.
(13) The closer motoneurones of each thoracic spiracle whose somata are in the pro-, meso- or metathoracic ganglia all receive the same excitatory synaptic inputs.
(14) They influence three aspects of ventilation; (a) the closing and opening movements of the thoracic spiracles, (b) some aspects of abdominal pumping movements and (c) the recruitment of some motoneurones controlling head pumping.
(15) We report here that three previously identified zygotic genes buttonhead (btd), empty spiracles (ems) and orthodenticle (otd) may behave like gap genes that mediate bcd function in the embryonic head.
(16) The dominant oscillator overrides local oscillators in the abdominal ganglia and thus sets the rhythm for the entire abdomen, and it also controls spiracle opening and closing in several thoracic and abdominal segments.
(17) Posterior spiracles of newly hatched first instar larvae of Hypoderma bovis (L.) and H. lineatum (DeVill.)
(18) The empty spiracles (ems) gene of Drosophila melanogaster is necessary for proper head formation and the development of the posterior spiracles.
(19) Despite this, the spiracles of one segment may remain shut while those on other segments continue to open and close rhythmically.
(20) We show that two genes, lines and empty spiracles, act downstream of tailless to repress central and promote terminal cell fates along the anteroposterior axis of the termini.