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Transverse Orientation
Transverse orientation, keeping a fixed angle on a distant source of light for orientation, is a proprioceptive response displayed by some insects such as moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...s. By maintaining a constant angular relationship to a bright celestial light, such as the moon, they can fly in a straight line. Celestial objects are so far away that, even after travelling great distances, the change in angle between the moth and the light source is negligible; further, the moon will always be in the upper part of the visual field, or on the horizon. When a moth encounters a much closer artificial light and uses it for navigation, the angle changes noticeably after only a short distance, in addition to being often below the horizon. The moth instinctively at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fixed Point (mathematics)
A fixed point (sometimes shortened to fixpoint, also known as an invariant point) is a value that does not change under a given transformation. Specifically, in mathematics, a fixed point of a function is an element that is mapped to itself by the function. In physics, the term fixed point can refer to a temperature that can be used as a reproducible reference point, usually defined by a phase change or triple point. Fixed point of a function Formally, is a fixed point of a function if belongs to both the domain and the codomain of , and . For example, if is defined on the real numbers by f(x) = x^2 - 3 x + 4, then 2 is a fixed point of , because . Not all functions have fixed points: for example, , has no fixed points, since is never equal to for any real number. In graphical terms, a fixed point means the point is on the line , or in other words the graph of has a point in common with that line. Fixed-point iteration In numerical analysis, ''fixed-point iter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle
In Euclidean geometry, an angle is the figure formed by two Ray (geometry), rays, called the ''Side (plane geometry), sides'' of the angle, sharing a common endpoint, called the ''vertex (geometry), vertex'' of the angle. Angles formed by two rays lie in the plane (geometry), plane that contains the rays. Angles are also formed by the intersection of two planes. These are called dihedral angles. Two intersecting curves may also define an angle, which is the angle of the rays lying tangent to the respective curves at their point of intersection. ''Angle'' is also used to designate the measurement, measure of an angle or of a Rotation (mathematics), rotation. This measure is the ratio of the length of a arc (geometry), circular arc to its radius. In the case of a geometric angle, the arc is centered at the vertex and delimited by the sides. In the case of a rotation, the arc is centered at the center of the rotation and delimited by any other point and its image by the rotation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orientation (geometry)
In geometry, the orientation, angular position, attitude, bearing, or direction of an object such as a line, plane or rigid body is part of the description of how it is placed in the space it occupies. More specifically, it refers to the imaginary rotation that is needed to move the object from a reference placement to its current placement. A rotation may not be enough to reach the current placement. It may be necessary to add an imaginary translation, called the object's location (or position, or linear position). The location and orientation together fully describe how the object is placed in space. The above-mentioned imaginary rotation and translation may be thought to occur in any order, as the orientation of an object does not change when it translates, and its location does not change when it rotates. Euler's rotation theorem shows that in three dimensions any orientation can be reached with a single rotation around a fixed axis. This gives one common way of representing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proprioception
Proprioception ( ), also referred to as kinaesthesia (or kinesthesia), is the sense of self-movement, force, and body position. It is sometimes described as the "sixth sense". Proprioception is mediated by proprioceptors, mechanosensory neurons located within muscles, tendons, and joints. Most animals possess multiple subtypes of proprioceptors, which detect distinct kinematic parameters, such as joint position, movement, and load. Although all mobile animals possess proprioceptors, the structure of the sensory organs can vary across species. Proprioceptive signals are transmitted to the central nervous system, where they are integrated with information from other sensory systems, such as the visual system and the vestibular system, to create an overall representation of body position, movement, and acceleration. In many animals, sensory feedback from proprioceptors is essential for stabilizing body posture and coordinating body movement. System overview In vertebrates, limb ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moth
Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of which have yet to be described. Most species of moth are nocturnal, but there are also crepuscular and diurnal species. Differences between butterflies and moths While the butterflies form a monophyletic group, the moths, comprising the rest of the Lepidoptera, do not. Many attempts have been made to group the superfamilies of the Lepidoptera into natural groups, most of which fail because one of the two groups is not monophyletic: Microlepidoptera and Macrolepidoptera, Heterocera and Rhopalocera, Jugatae and Frenatae, Monotrysia and Ditrysia.Scoble, MJ 1995. The Lepidoptera: Form, function and diversity. Oxford, UK: Oxford University Press; 404 p. Although the rules for distinguishing moths from butterflies are not well establishe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Karl Kruszelnicki
Karl Sven Woytek Sas Konkovitch Matthew Kruszelnicki (born 1948), often referred to as "Dr Karl", is an Australian science communicator and populariser, who is known as an author and a science commentator on Australian radio and television. Kruszelnicki is the Julius Sumner Miller Fellow in the Science Foundation for Physics at the School of Physics, University of Sydney. Early life Kruszelnicki () was born in Helsingborg, Sweden, to Polish parents, Rina and Ludwik. Kruszelnicki's background was hidden from him for a long time, with his mother having told him that she was Swedish and a Lutheran but she was, in fact, Polish and Jewish. Both his parents were Holocaust survivors. His father Ludwik, a Polish Gentile, was turned in to the Gestapo for smuggling Jews out of Poland and was imprisoned at Sachsenhausen, a concentration camp used mainly for political prisoners. As the end of World War II approached, Ludwik avoided execution by swapping identities with a dead person. Rin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABC Online
The Australian Broadcasting Corporation (ABC) is the national broadcaster of Australia. It is principally funded by direct grants from the Australian Government and is administered by a government-appointed board. The ABC is a publicly-owned body that is politically independent and fully accountable, with its charter enshrined in legislation, the ''Australian Broadcasting Corporation Act 1983''. ABC Commercial, a profit-making division of the corporation, also helps to generate funding for content provision. The ABC was established as the Australian Broadcasting Commission on 1 July 1932 by an act of federal parliament. It effectively replaced the Australian Broadcasting Company, a private company established in 1924 to provide programming for A-class radio stations. The ABC was given statutory powers that reinforced its independence from the government and enhanced its news-gathering role. Modelled after the British Broadcasting Corporation (BBC), which is funded by a televi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
