(n.) The shadow cast, in an eclipse, where the light is partly, but not wholly, cut off by the intervening body; the space of partial illumination between the umbra, or perfect shadow, on all sides, and the full light.
(n.) The part of a picture where the shade imperceptibly blends with the light.
Example Sentences:
(1) Our analysis showed that the interpolation errors are proportional to the curvature of the dose distribution and are relatively high in regions on either side of, but not including, the steepest part of the penumbra.
(2) Analysis of the penumbra width of cross dose distributions, as a function of field sizes, allowed us to postulate that the dmax shift could be due to the phantom scattered photons, which in turn were generated by the collimator scattered photons.
(3) If true, this is the first demonstration of the ischemic penumbra by MR imaging and may reflect our use of Wistar rats, a new image analysis technique, and ultra-high resolution MR imaging.
(4) The combination for this applicator of sharp penumbra and low out-of-field dose leads to reduced lung and opposite breast doses.
(5) An extracellular acidosis that occurs in the penumbra zone was investigated in vitro as to its role in the formation of cytotoxic cell swelling.
(6) The ischemic thresholds for the initial increase in CMRG and the complete depletion of ATP content represent the metabolic equivalent of the penumbra zone and provide a basis for the evaluation of therapeutic procedures for the treatment of stroke.
(7) If the entire cross-section is blocked, the point will be in the umbra of the shadow; if only a portion of the light is blocked, the point will be in the penumbra of the shadow.
(8) The mechanisms involved in this sequence of events and the role of pH changes in the development of the so-called "ischaemic penumbra" are discussed.
(9) In the light of these findings, we suggest that use of a selective antagonist of LTs may be helpful in reducing the ischemic penumbra during acute cerebral ischemia by controlling the vasogenic edema.
(10) Opening the hinge adjustment restores field flatness, without changing penumbra or the inverse square law behavior of the teletherapy unit.
(11) The area of "penumbra" could be estimated in regions with CBF value just above this threshold.
(12) In the penumbra zone, comparable trends were noted in OER and CMRO2 but the difference in the changes between the two groups did not reach statistical significance.
(13) The agreement is within experimental errors both in the penumbra region and along the central ray of the asymmetric field.
(14) These results confirm the concept of a metabolic penumbra.
(15) These wedges were designed to increase the penumbra width at the field junction from about 1.5 to about 3.5 cm, to achieve dose uniformity.
(16) These studies suggest that 1) the expression of 72-kd heat-shock protein in neurons precedes the development of ischemic cellular alterations detectable by conventional hematoxylin and eosin light microscopy methods; 2) there is a hierarchy of cell types and anatomic sites that express 72-kd heat-shock protein, and this hierarchy reflects cellular and anatomic vulnerability to ischemic cell damage; and 3) 72-kd heat-shock protein induction in neurons bordering a necrotic ischemic core may be the morphological equivalent of the ischemic penumbra.
(17) While within the penumbra, some direct sunlight falls on the Moon but little darkening of the disc will be noticed until a few minutes before the Moon begins to enter the umbra at 19:23.
(18) Measurements with the diode interfaced to an X-Y recorder required only a fraction of the time required with the chambers, minimizing error due to change in machine output, and permitted resolution of isodose lines in the penumbra.
(19) A typical spot has a central dark umbra, surrounded by a lighter penumbra.
(20) The rate in the penumbra differed (P = .01) from that in the predicted low-dose region, where scotoma did not increase with time.
Umbra
Definition:
(n.) The conical shadow projected from a planet or satellite, on the side opposite to the sun, within which a spectator could see no portion of the sun's disk; -- used in contradistinction from penumbra. See Penumbra.
(n.) The central dark portion, or nucleus, of a sun spot.
(n.) The fainter part of a sun spot; -- now more commonly called penumbra.
(n.) Any one of several species of sciaenoid food fishes of the genus Umbrina, especially the Mediterranean species (U. cirrhosa), which is highly esteemed as a market fish; -- called also ombre, and umbrine.
Example Sentences:
(1) If the entire cross-section is blocked, the point will be in the umbra of the shadow; if only a portion of the light is blocked, the point will be in the penumbra of the shadow.
(2) The frequency of chromosome aberrations was measured in cultured Umbra limi heart (U1-H) and Chinese hamster ovary (CHO) cells following exposure to the polycyclic aromatic hydrocarbons (PAH) 3,4-benzopyrene (BP), 1,2,5,6-dibenzanthracene (DBA), 1,2-benzanthracene (BA), and pyrene (PY), activated using S9 prepared from rainbow trout liver.
(3) While within the penumbra, some direct sunlight falls on the Moon but little darkening of the disc will be noticed until a few minutes before the Moon begins to enter the umbra at 19:23.
(4) On that occasion, the Moon traversed the northern part of the umbra and its southern regions, which just missed the shadow's core, are relatively dark.
(5) A typical spot has a central dark umbra, surrounded by a lighter penumbra.
(6) Due to the very limited amount of knowledge available on the cytochemistry and architecture of fish chromosomes, an extensive banding study was carried out on chromosomes of the central mudminnow, Umbra limi.
(7) The mudminnow, Umbra pygmaea, was chosen for this study, because of its ideal karyotype of 22 large chromosomes.
(8) Artificial "calculus", consisting of a mixture of shellac, umbra, pumice and plaster dissolved in ethanol, was painted on the root surfaces.
(9) The Moon stands over the southern Indian Ocean as it passes through the central dark umbra of the Earth's shadow, plunging deeper into the shadow than during any eclipse since 2000.
(10) It was concluded that the chromosomes of Umbra limi displayed typical responses to low level radiation exposure and that this fish would be an ideal cytogenetics model for this study of induced chromosome aberrations in fishes.
(11) The Moon's W limb has withdrawn from the umbra by 23:02 and finally exits the penumbra at 00:01.
(12) Totality, with the Moon entirely within the umbra, lasts from 20:22 until 22:03 with mid eclipse at 21:13.
(13) An in vivo system for the detection of sister chromatid exchange (SCE) in the central mudminnow, Umbra limi, is presented.
(14) A parasite of Plica plica in Guyana, previously called P. cnemidophori, is designated P. guyannense, while identification of Plica umbra parasites as P. tropiduri is corrected to P. vacuolatum and Fallisia simplex.
(15) The umbra is not illuminated evenly, though, since less of this indirect light penetrates to its core and the amount reaching different zones of the umbra is affected by varying atmospheric conditions.
(16) nov. from Plica umbra of Guyana; P. minasense tegui subsp.
(17) In the second type, motor activity was observed at any time; this type of periodism was typical of the dogfish Squalus acanthias and the hunchback Sciaena umbra.
(18) The central mudminnow, Umbra limi, was chosen fro this study because of its ideal karyotype consisting of 22 large meta- and submetacentric chromosomes.
(19) Observers in SE England may just glimpse the end of totality, but most of us may see nothing until it begins to emerge from the umbra.
(20) Mudminnows (Umbra pygmaea) and gar (Lepisosteus platyrhincus) were quite tolerant of exposure to acidic waters.