penumbra

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penumbra

 [pĕ-num´brah]
1. the part of a shadow in which there is a small amount of illumination from a light source.
2. blurring at the edges of a structure on a radiograph.

pe·num·bra

(pe-nŭm'bră),
The region of partial illumination or radiation caused by light or x-rays not originating from a point source; also called geometric unsharpness.
[Mod. L., fr. L. paene, almost, + umbra, shadow]

pe·num·bra

(pĕ-nŭm'bră)
1. radiology The blurred margin of an image.
2. radiation physics The region at the edges of a radiation beam over which a rapid change in dosage rate occurs.
Synonym(s): geometric unsharpness.
[Mod. L., fr. L. paene, almost, + umbra, shadow]

penumbra 

1. Region of very low illumination on a dark background.
2. Zone in which the brightness varies from some illumination to zero (umbra) in the shadow cast by an opaque object intercepting light from an extensive light source. See shadow.

pe·num·bra

(pĕ-nŭm'bră)
1. radiology the blurred margin of an image.
2. radiation physics the region at the edges of a radiation beam over which a rapid change in dosage rate occurs.
Synonym(s): geometric unsharpness.
[Mod. L., fr. L. paene, almost, + umbra, shadow]

penumbra

a blurred edge to an image, a halo effect, in an x-ray film caused usually by an overlarge focal spot exacerbated by a long object-to-film distance.
References in periodicals archive ?
statutes does not achieve its goal of giving penumbral value to
The group developed three small trailing penumbral spots on Aug 31 type Eao.
downward spiral that is this crisis's penumbral component, as
Katharine Bassard's interesting study of the changing symbolism of the cross in African American literature reveals authors in stark contrast New's Dickinson, who looks for spiritual vitality in the penumbral recesses of metaphor.
Douglas, who originated the notion of rights found in the Constitution's "penumbras" and "emanations," nevertheless made a point of excluding the Ninth Amendment from the Supreme Court's most famous penumbral ruling.
If the notion of penumbral privacy was novel, it certainly seemed less so when based upon the settled line of authority Meyer, Pierce, and Skinner was said to establish.
New Delhi, Feb 9 (ANI): A penumbral eclipse on a full moon day will be visible throughout country today.
Chapters address specific questions such as the role of glutamate/NMDA, the mechanisms of penumbral cells, the importance of intermittent hypoxia, and gene regulation under stressful conditions.
Given the penumbral riches, both historical and invented, that dance around the core narrative of the film, the college debates themselves barely register: the positions are repeatedly stacked in favor of Wiley, the interactions of the team are merely sketched, and deeper pedagogical questions of lasting importance remain buried.
Here are penumbral "individuals" who are distinctively endowed with techne, are highly skilled at what they do, and they willingly heed authority.
A partial eclipse will be seen within the much broader path of the moon's penumbral shadow, which includes northeastern North America, and most of Europe and Asia," it added.
Was the penumbral crime--it could be conspiracy, perjury, official misconduct, or a host and variety of others constituting "obstruction of justice" that always orbit a core crime investigation, if there ever was one--just another of the available pressure points, power-plays, and mechanisms in the powerful prosecutorial playbook?