(n.) The time when the sun enters one of the equinoctial points, that is, about March 21 and September 22. See Autumnal equinox, Vernal equinox, under Autumnal and Vernal.
(n.) Equinoctial wind or storm.
Example Sentences:
(1) Dose rates are integrated with respect to time to obtain estimates of mean doses for various periods during clear days at Rockville in mid summer and near the autumnal equinox.
(2) The date of the spring equinox varies from 19 to 21 March depending on location and corrections due to the mismatch between the Gregorian calendar, which logs 365 days a year, and the duration of Earth's orbit around the sun, which takes 365.25 days to complete.
(3) Plasma melatonin was measured at the summer and winter solstices and the autumn and spring equinoxes in Romney Marsh sheep held under natural conditions in South Australia (35 degrees S).
(4) Female Suffolk sheep were pinealectomized around the vernal equinox to eliminate the major environmental input to the reproductive system (photoperiod) and then either isolated from, or maintained with, pineal-intact gonad-intact sheep.
(5) At 6-14 days after each of the solstices and equinoxes, six females were exposed to a photoperiod equivalent to the natural day length at these times.
(6) Seven out of 14 acrophases of cyclic indices occurred just before autumnal equinox and three before vernal equinox.
(7) While the equinox signals a time when day and night are equal, the moment when both share 12 hours apiece happens days earlier, because of atmospheric effects.
(8) At approximately the spring and autumn equinox and the summer and winter solstice, rats were killed at 3-h intervals over a 24 h period and their serum thyroxine (T4), triiodothyronine (T3) and reverse T3 levels were determined.
(9) At higher latitudes, where changes in daylength are pronounced, a steep increase in human conceptions coincides with the vernal equinox.
(10) With less than a week to go until the Sun crosses northwards over the equator at the vernal equinox, it is showing real signs of rebirth in another respect.
(11) Downstream of the zone, a man called Sanders arrives at a remote town called Port Matarre just before the equinox.
(12) In a group of six rams, the seasonal changes of melatonin were characterized in samples collected at 10-min intervals for an equal period before and after the median of the scotophase during the spring (March) and the autumn (September) equinoxes, and also during the summer (June) and the winter (December) solstices.
(13) The mitotic activity in the adenohypophysis of male rats during a 24 hours' cycle has been studied at the time of the spring equinox.
(14) Shortly after the autumnal equinox, three groups of ovariectomized ewes bearing s.c. Silastic implants of estradiol were placed in different lighting environments.
(15) In both stations, at solstice and equinox, thirty 15 month-old Holstein bulls were blood sampled for plasma LH, testosterone, thyroxine and triiodothyronine determination.
(16) Swedish law would not allow them to be sued in Sweden, but the British publishers of the paper, Equinox, withdrew it under the threat of a libel suit in the English courts.
(17) Interpreted according to this hypothesis, the sexual cycle of the mink under natural photoperiodic conditions is also explained by seasonal gonadotropic stimulation beginning after the autumn equinox when in our latitudes daily light duration is less than 12 hr.
(18) At the equinoxes and solstices, unrestricted subjects had hourly urine collections followed by venous blood sampling taken under natural light conditions for 24 hours.
(19) For those in the southern hemisphere, the same equinox marks the arrival of autumn and longer nights.
(20) The rats were analyzed at 3 h intervals during 24 h approximately at the time of the vernal and autumnal equinox and at the winter and summer solistice.
Nutation
Definition:
(n.) The act of nodding.
(n.) A very small libratory motion of the earth's axis, by which its inclination to the plane of the ecliptic is constantly varying by a small amount.
(n.) The motion of a flower in following the apparent movement of the sun, from the east in the morning to the west in the evening.
(n.) Circumnutation.
Example Sentences:
(1) The effect on the signal intensities of cerebrospinal fluid (CSF) and iophendylate (Pantopaque) and on CSF-iophendylate contrast was studied in vitro with a small-nutation-angle (alpha) gradient refocused magnetic resonance (MR) imaging technique (GRASS) as alpha, repetition time (TR), and echo time (TE) were varied.
(2) 2D 27Al nutation MAS NMR was used to corroborate the line assignment for the as-synthesized and the rehydrated AlPO4-17.
(3) The families that do not show consistent differences are not necessarily harbouring nutations at the same locus, or the same mutation at any particular locus.
(4) The mutation which makes T7 DNA sensitive to the endonuclease is separable from the amber nutation and located between am28 and am233 (gene 6).
(5) Solid-state 27Al NMR spectra of several aluminophosphate molecular sieves have been recorded with conventional magic-angle spinning (MAS), double-rotation (DOR) and quadrupole nutation with fast MAS.
(6) Enhanced resolution was obtained in the quadrupole nutation experiment at certain radiofrequency pulse strengths.
(7) There was a high correlation between measurements obtained with the variable nutation and partial saturation techniques.
(8) The one phase is the intermediate phase where dilatation of the cervix is almost complete and where there is an instinctive reflex that delivery is going to take place and this is very strong, and this is what starts off the oscillation (contra-nutation) of the sacrum and full engagement.
(9) The apparent T2 is influenced by the magnitude of the nutation angle inhomogeneity across the slice and paradoxically is not always more accurate with larger numbers of echoes.
(10) The accuracy of measurement of the spin-lattice relaxation time (T1) in biological systems using the variable nutation angle method is discussed using computer simulations.
(11) The spin nutation properties of frequency selective (space selective in combination with a magnetic field gradient) trains of radiofrequency micropulses were studied in a numeric model.
(12) Cross-polarization magic-angle spinning 13C and 15N NMR, rotational-echo double resonance 13C NMR, and delays alternating with nutation for tailored excitation-difference 13C NMR spectra have been obtained from lyophilized cell walls of Bacillus subtilis grown on a synthetic medium containing D,L-[2-13C, 15N]aspartate and D-[1-13C]alanine.
(13) Transparent pulses are defined by the property of having no net effect on stationary spins, while selectively nutating and dephasing flowing spins.
(14) This "variable nutation" techniques was investigated using a T1 phantom.
(15) We conclude that the variable nutation method may allow measurement of T1 relaxation times with a significant reduction in acquisition time compared to partial saturation techniques.