ペナンブラ
WordNet
- a fringe region of partial shadow around an umbra
- of questionable or minimal quality; "borderline grades"; "marginal writing ability" (同)marginal
- a line determining the limits of an area (同)edge, bound
- the line or plane indicating the limit or extent of something (同)bound, bounds
- of or pertaining to the region of partial shadow around an umbra
PrepTutorEJDIC
- (日食・月食の)半影 / (太陽の黒点周囲り)半影部 / (絵画で)明暗(濃淡)の境目
- (…の)国境線,境界線《+『of』(『between』)+『名』[+『and』+『名』]》 / 国境線上の,境界線上の / どっちつかずの,不明確な
- 『境界線』,境(border) / 限界
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2016/03/24 16:18:18」(JST)
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Shadows
For other uses, see Umbra (disambiguation) and Penumbra (disambiguation).
Umbra, penumbra, and antumbra, for a lunar eclipse
Umbra (A) and penumbra (B)
The umbra, penumbra and antumbra are three distinct parts of a shadow, created by any light source after impinging on an opaque object. For a point source only the umbra is cast.
These names are most often used for the shadows cast by celestial bodies, though they are sometimes used to describe levels of darkness, such as in sunspots.
Contents
- 1 Umbra
- 2 Penumbra
- 3 Antumbra
- 4 See also
- 5 References
Umbra
Umbra, penumbra and antumbra formed through windows and shutters
The umbra (Latin for "shadow") is the innermost and darkest part of a shadow, where the light source is completely blocked by the occluding body. Such an opaque object does not let light through it. An observer in the umbra experiences a total eclipse. The umbra of a round body occluding a round light source forms a right circular cone; to a viewer at the cone's apex, the two bodies are equal in apparent size. The distance from the Moon to the apex of its umbra is roughly equal to that between the Moon and Earth. Because the Earth is 3.7 times wider than the Moon, its umbra extends correspondingly farther, roughly 1.4 million kilometers.[1]
Penumbra
"Penumbra" redirects here. For other uses, see Penumbra (disambiguation).
The penumbra (from the Latin paene "almost, nearly" and umbra "shadow") is the region in which only a portion of the light source is obscured by the occluding body. An observer in the penumbra experiences a partial eclipse. An alternative definition is that the penumbra is the region where some or all of the light source is obscured (i.e., the umbra is a subset of the penumbra). For example, NASA's Navigation and Ancillary Information Facility defines that a body in the umbra is also within the penumbra.[2]
Earth's shadow, to scale, showing the extent of the umbral cone beyond the Moon's orbit (yellow dot, also to scale)
Antumbra
The antumbra (from Latin ante, "before") is the region from which the occluding body appears entirely contained within the disc of the light source. An observer in this region experiences an annular eclipse, in which a bright ring is visible around the eclipsing body. If the observer moves closer to the light source, the apparent size of the occluding body increases until it causes a full umbra.
See also
References
- ^ "Lecture 9: Eclipses of the Sun & Moon". ohio-state.edu. Retrieved July 16, 2015.
- ^ Event Finding Subsystem Preview Navigation and Ancillary Information Facility.
UpToDate Contents
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English Journal
- Acute Blockage of Notch Signaling by DAPT Induces Neuroprotection and Neurogenesis in the Neonatal Rat Brain After Stroke.
- Li Z1, Wang J2, Zhao C1, Ren K1, Xia Z3, Yu H4, Jiang K5,6.
- Translational stroke research.Transl Stroke Res.2016 Apr;7(2):132-140. Epub 2015 Dec 22.
- Notch signaling is critically involved in various biological events. Notch undergoes cleavage by the γ-secretase enzyme to release Notch intracellular domain that will translocate into nucleus to result in expression of target gene. γ-Secretase inhibitors have been developed as potential treatment
- PMID 26691164
- Dosimetric characteristics of brass mesh as bolus under megavoltage photon irradiation.
- Richmond ND1, Daniel JM1, Whitbourn JR1, Greenhalgh AD1.
- The British journal of radiology.Br J Radiol.2016 Mar;89(1059):20150796. doi: 10.1259/bjr.20150796. Epub 2016 Jan 12.
- OBJECTIVE: This article presents a set of dosimetric measurements describing the properties of brass mesh (Whiting and Davis, Attleboro Falls, MA) under megavoltage photon irradiation conditions, with particular relevance to its use in breast radiotherapy.METHODS: The effectiveness of brass mesh as
- PMID 26756812
- Normobaric hyperoxia markedly reduces brain damage and sensorimotor deficits following brief focal ischaemia.
- Ejaz S1, Emmrich JV2, Sitnikov SL1, Hong YT3, Sawiak SJ3, Fryer TD3, Aigbirhio FI3, Williamson DJ3, Baron JC4.
- Brain : a journal of neurology.Brain.2016 Mar;139(Pt 3):751-64. doi: 10.1093/brain/awv391. Epub 2016 Jan 14.
- 'True' transient ischaemic attacks are characterized not only clinically, but also radiologically by a lack of corresponding changes on magnetic resonance imaging. During a transient ischaemic attack it is assumed that the affected tissue is penumbral but rescued by early spontaneous reperfusion. Th
- PMID 26767570
Japanese Journal
- 当院における急性主幹動脈閉塞症に対する血栓回収療法 : Penumbra 5MAX ACE導入後の治療成績 (第36回山形県対脳卒中治療研究会)
- Effectiveness of Mechanical Thrombectomy Using the Penumbra System for Acute Ischemic Stroke Due to Large Vessel Occlusion
- JNET : journal of neuroendovascular therapy : official journal of the Japanese Society for Neuroendovascular Therapy 10(3), 101-107, 2016-07
- NAID 40020894359
- 脳梗塞の診断の変遷と現況 (特集 脳卒中 : 新時代の治療を求めて)
Related Links
- スウェーデンのデベロッパ,Frictional Gamesの開発した「Penumbra」は,フリーのアドベンチャーゲームだ。プレイヤーは一人の青年となり,失踪した父親の手がかりを追って,古いノートに記されたグリーンランドの某所に出かける。
- Penumbra SMART COIL Neurovascular Access Devices BENCHMARK 071 5MAX and 4MAX DDC Neuron System Select Catheter PX SLIM Velocity® Surgical Tools Apollo System Peripheral Peripheral Thrombectomy ...
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