What's the difference between penumbra and shadow?

Penumbra


Definition:

  • (n.) An incomplete or partial shadow.
  • (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.

Shadow


Definition:

  • (n.) Shade within defined limits; obscurity or deprivation of light, apparent on a surface, and representing the form of the body which intercepts the rays of light; as, the shadow of a man, of a tree, or of a tower. See the Note under Shade, n., 1.
  • (n.) Darkness; shade; obscurity.
  • (n.) A shaded place; shelter; protection; security.
  • (n.) A reflected image, as in a mirror or in water.
  • (n.) That which follows or attends a person or thing like a shadow; an inseparable companion; hence, an obsequious follower.
  • (n.) A spirit; a ghost; a shade; a phantom.
  • (n.) An imperfect and faint representation; adumbration; indistinct image; dim bodying forth; hence, mystical representation; type.
  • (n.) A small degree; a shade.
  • (n.) An uninvited guest coming with one who is invited.
  • (n.) To cut off light from; to put in shade; to shade; to throw a shadow upon; to overspead with obscurity.
  • (n.) To conceal; to hide; to screen.
  • (n.) To protect; to shelter from danger; to shroud.
  • (n.) To mark with gradations of light or color; to shade.
  • (n.) To represent faintly or imperfectly; to adumbrate; hence, to represent typically.
  • (n.) To cloud; to darken; to cast a gloom over.
  • (n.) To attend as closely as a shadow; to follow and watch closely, especially in a secret or unobserved manner; as, a detective shadows a criminal.

Example Sentences:

  • (1) Findings on plain X-ray of the abdomen, using the usual parameters of psoas and kidney shadows in the Nigerian, indicate that the two communities studied are similar but urinary calculi and urinary tract distortion are significantly more prominent in the community with the higher endemicity of urinary schistosomiasis.
  • (2) One of the most interesting aspects of the shadow cabinet elections, not always readily interpreted because of the bizarre process of alliances of convenience, is whether his colleagues are ready to forgive and forget his long years as Brown's representative on earth.
  • (3) Speaking to pro-market thinktank Reform, Milburn called for “more competition” and said the shadow health team were making a “fundamental political misjudgment” by attempting to roll back policies he had overseen.
  • (4) Shadow education secretary Tristram Hunt said people would see through her attempts to distance herself from Gove.
  • (5) An attempt to eliminate the age effect by adjusting for age differences in monaural shadowing errors, fluid intelligence, and pure-tone hearing loss did not succeed.
  • (6) A ­senior shadow minister, who has not been named by the Telegraph in its exposé of MPs' expenses , was yesterday asked by county councillors not to campaign for next month's local elections.
  • (7) Luciana Berger, Labour shadow secretary for mental health, also expressed alarm.
  • (8) A small band of shadow cabinet members have lined up to refuse to serve in posts they haven’t even been offered, on the basis of objection to economic policies they clearly haven’t read.
  • (9) If two sources of radiation are used, it is decisive to cover with lead the zones of half-shadow on the field limits.
  • (10) The amount of intimidation and abuse that has taken place make it very unlikely that women will be clamouring to go back.” Another former shadow minister said they were also not convinced they would stand again.
  • (11) The risk of "Gesunde Befundträger" (healthy carriers of pulmonary lesions) to develop pulmonary tuberculosis is compared with that of persons with X-ray shadows in the lung.
  • (12) These echoes, however, are not associated with acoustic shadowing.
  • (13) Ed Balls, the shadow home secretary, today called on the head of the Metropolitan police to reopen the investigation into phone hacking by the News of the World.
  • (14) A 43-year-old lady was hospitalized due to easy fatiguability in the legs during exercise, and for evaluation of an abnormal shadow in the chest X-ray, and hypertension.
  • (15) The shadow attorney general, Mark Dreyfus, said Heydon had “got it wrong” in his decision and had “not really approached this as an ordinary, fair-minded person would”.
  • (16) I think it would have been appropriate and right and respectful of people’s feelings to have done so.” There was also confusion over Labour policy sparked by conflicting comments made by Corbyn and his new shadow work and pensions secretary, Owen Smith.
  • (17) He has his job to do and he has to do it the way he thinks best.” On Saturday night, in a sign of the growing concern at the top of the party about the affair, one shadow cabinet member told the Observer : “The issue is already echoing back at us on the doorsteps.” At all levels, there was despair that the furore had turned the spotlight on to Labour’s difficulties as a time when the party had hoped to take advantage of the Tories’ second byelection loss at the hands of Ukip.
  • (18) The first site we explored was a big burial cairn in the shadow of Carn Menyn, where the Stonehenge bluestones come from."
  • (19) There will have to be very direct conversations about his platform,” one shadow cabinet member said, but others have insisted there can be no accommodation with Corbyn’s politics.
  • (20) He is shadow home secretary and will have to defend himself.