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Aberration
An aberration is something that deviates from the normal way. Aberration may also refer to: Biology and medicine *Form (zoology) or aberration, a rare mutant butterfly or moth wing pattern *Cardiac aberrancy, aberration in the shape of the EKG signal *Chromosome aberration, abnormal number or structure of chromosomes Entertainment *''Aberration'', a DLC for the video game '' Ark: Survival Evolved'' * ''Aberration'' (film), a 1997 horror film * ''Aberration'' (EP), by Neurosis, 1989 *Aberrations, or abbies, human-like creatures in the American TV series ''Wayward Pines'' Optics and physics *Astronomical aberration, phenomenon wherein objects appear to move about their true positions in the sky *Chromatic aberration, failure of a lens to focus all colors on the same point * Defocus aberration, in which an image is out of focus *Optical aberration, an imperfection in image formation by an optical system * Relativistic aberration, the distortion of light at high velocities *Spher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomical Aberration
In astronomy, aberration (also referred to as astronomical aberration, stellar aberration, or velocity aberration) is a phenomenon which produces an apparent motion of celestial objects about their true positions, dependent on the velocity of the observer. It causes objects to appear to be displaced towards the direction of motion of the observer compared to when the observer is stationary. The change in angle is of the order of ''v/c'' where ''c'' is the speed of light and ''v'' the velocity of the observer. In the case of "stellar" or "annual" aberration, the apparent position of a star to an observer on Earth varies periodically over the course of a year as the Earth's velocity changes as it revolves around the Sun, by a maximum angle of approximately 20 arcseconds in right ascension or declination. The term ''aberration'' has historically been used to refer to a number of related phenomena concerning the propagation of light in moving bodies. Aberration is distinct fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Aberration
In optics, aberration is a property of optical systems, such as lenses, that causes light to be spread out over some region of space rather than focused to a point. Aberrations cause the image formed by a lens to be blurred or distorted, with the nature of the distortion depending on the type of aberration. Aberration can be defined as a departure of the performance of an optical system from the predictions of paraxial optics. In an imaging system, it occurs when light from one point of an object does not converge into (or does not diverge from) a single point after transmission through the system. Aberrations occur because the simple paraxial theory is not a completely accurate model of the effect of an optical system on light, rather than due to flaws in the optical elements. An image-forming optical system with aberration will produce an image which is not sharp. Makers of optical instruments need to correct optical systems to compensate for aberration. Aberration can be ana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus ''shift''). Longitudinal aberration is typical at long focal lengths. Transverse aberration occurs when different wavelengths are focused at different posit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Aberration
In optics, spherical aberration (SA) is a type of aberration found in optical systems that have elements with spherical surfaces. Lenses and curved mirrors are prime examples, because this shape is easier to manufacture. Light rays that strike a spherical surface off-centre are refracted or reflected more or less than those that strike close to the centre. This deviation reduces the quality of images produced by optical systems. Overview A spherical lens has an aplanatic point (i.e., no spherical aberration) only at a radius that equals the radius of the sphere divided by the index of refraction of the lens material. A typical value of refractive index for crown glass is 1.5 (see list), which indicates that only about 43% of the area (67% of diameter) of a spherical lens is useful. It is often considered to be an imperfection of telescopes and other instruments which makes their focusing less than ideal due to the spherical shape of lenses and mirrors. This is an important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Defocus Aberration
In optics, defocus is the aberration in which an image is simply out of focus. This aberration is familiar to anyone who has used a camera, videocamera, microscope, telescope, or binoculars. Optically, defocus refers to a translation of the focus along the optical axis away from the detection surface. In general, defocus reduces the sharpness and contrast of the image. What should be sharp, high-contrast edges in a scene become gradual transitions. Fine detail in the scene is blurred or even becomes invisible. Nearly all image-forming optical devices incorporate some form of focus adjustment to minimize defocus and maximize image quality. In optics and photography The degree of image blurring for a given amount of focus shift depends inversely on the lens f-number. Low f-numbers, such as to 2.8, are very sensitive to defocus and have very shallow depths of focus. High f-numbers, in the 16 to 32 range, are highly tolerant of defocus, and consequently have large dept ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Relativistic Aberration
Relativistic aberration is the relativistic version of aberration of light, including relativistic corrections that become significant for observers who move with velocities close to the speed of light. It is described by Einstein's special theory of relativity. Suppose, in the reference frame of the observer, the source is moving with speed v\, at an angle \theta_s\, relative to the vector from the observer to the source at the time when the light is emitted. Then the following formula, which was derived by Einstein in 1905 from the Lorentz transformation, describes the aberration of the light source, \theta_o\,, measured by the observer: :\cos \theta_o=\frac \, In this circumstance, the rays of light from the source which reach the observer are tilted towards the direction of the source's motion (relative to the observer). It is as if light emitted by a moving object is concentrated conically, towards its direction of motion; an effect called relativistic beaming. Also, light ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome Aberration
A chromosomal abnormality, chromosomal anomaly, chromosomal aberration, chromosomal mutation, or chromosomal disorder, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities, where there is an atypical number of chromosomes, or as structural abnormalities, where one or more individual chromosomes are altered. Chromosome mutation was formerly used in a strict sense to mean a change in a chromosomal segment, involving more than one gene. Chromosome anomalies usually occur when there is an error in cell division following meiosis or mitosis. Chromosome abnormalities may be detected or confirmed by comparing an individual's karyotype, or full set of chromosomes, to a typical karyotype for the species via genetic testing. Numerical abnormality An abnormal number of chromosomes is called aneuploidy, and occurs when an individual is either missing a chromosome from a pair (resulting in monosomy) or has more than two chromosome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aberration (film)
''Aberration'' is a 1997 horror film directed by Tim Boxell. It was set in the United States and shot in New Zealand, and stars Pamela Gidley as a woman who moves to her old childhood cabin in the woods, only to discover that it is overrun by a pack of murderous lizards. Plot An oddball animal biologist local field researcher named Marshall Clarke (Simon Bossell) is investigating the disappearance of local wildlife, and stumbles upon an unidentified slimy residue. Meanwhile, a woman named Amy Harding (Pamela Gidley) moves into her old cabin in the woods of Langdon, where she spent her family holidays as a child, along with her cat, Frankie, a large sum of money, and all of the personal belongings. While attempting to make the cabin habitable, Amy realises that a moist substance has spoiled a piece of cake she is about to eat and fears she may have mice. Outside, she meets Mr. Peterson (Norman Forsey), looking for his dog Florence, which was killed by an unseen creature, he te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wayward Pines
''Wayward Pines'' is an American mystery science fiction television series based on the ''Wayward Pines'' novels by Blake Crouch. Developed for television by Chad Hodge, the pilot was directed by M. Night Shyamalan, with both as executive producers. The series premiered on Fox on May 14, 2015, and the first season concluded on July 23, 2015. On December 9, 2015, Fox renewed the series for a second season which aired from May 25 to July 27, 2016. After the second season, the series was canceled in 2018. Premise In the first season, Ethan Burke (Matt Dillon) is a U.S. Secret Service agent investigating the disappearance of two fellow agents in the mysterious small town of Wayward Pines, Idaho. Ethan awakens from a car accident unable to contact the outside world and unable to leave. He finds one of the agents dead and the other, his former lover Kate Hewson (Carla Gugino), settled down in the seemingly idyllic town. But the inhabitants of Wayward Pines are trapped there by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiac Aberrancy
Cardiac aberrancy is a type of aberration in the shape of the EKG signal, representing activation of the heart muscle via the electrical conduction system of the heart. Aberration occurs when the electrical activation of the heart, which is caused by a series of action potentials is conducting improperly, which can be due to: * left anterior fascicular block * left posterior fascicular block * bundle branch block * Wolff–Parkinson–White syndrome Wolff–Parkinson–White syndrome (WPWS) is a disorder due to a specific type of problem with the electrical system of the heart. About 60% of people with the electrical problem developed symptoms, which may include an abnormally fast heartbeat ... See also * Electrocardiography {{circulatory-stub Cardiac electrophysiology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Survival Evolved
''Ark: Survival Evolved'' (stylized as ''ARK'') is a 2017 action-adventure survival video game developed by Studio Wildcard. In the game, players must survive being stranded on one of several maps filled with roaming dinosaurs, fictional fantasy monsters, and other prehistoric animals, natural hazards, and potentially hostile human players. The game is played from either a third-person or first-person perspective and its open world is navigated by foot or by riding a prehistoric animal. Players can use firearms and improvised weapons to defend against hostile humans and creatures, with the ability to build bases as a defense on the ground and on some creatures. The game has both single-player and multiplayer options. Multiplayer allows the option to form tribes of Players in a server. The max number of tribe mates varies from each server. In this mode, all tamed dinosaurs and building structures are usually shared between the members. There is a PvE mode where players cannot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Form (zoology)
In zoology, the word "form" or ''forma'' (literally Latin for form) is a strictly informal term that is sometimes used to describe organisms. Under the ''International Code of Zoological Nomenclature'' the term has no standing (it is not accepted). In other words, although form names are Latin, and are sometimes wrongly appended to a binomial name, in a zoological context, forms have no taxonomic significance at all. Usage of the term Some zoologists use the word "form" or "forma" to describe variation in animals, especially insects, as part of a series of terms and abbreviations that are appended to the binomen or trinomen. Many 'typical specimens' may be described, but none should be considered absolute, unconditional or categorical. Forms have no official status, though they are sometimes useful in describing altitudinal or geographical clines. As opposed to morphs (see below), a subpopulation usually consists of a single form only at any given point of time. ''forma geogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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