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Sinistral
Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use different terms (such as dextro- and laevo-rotary in chemistry, or clockwise and anticlockwise in physics) or simply use left and right (as in anatomy). Relative direction and chirality are distinct concepts. Relative direction is from the point of view of the observer; a completely symmetric object has a left side and a right side, from the observer's point of view, if the top and bottom and direction of observation are defined. Chirality, however, is observer-independent: no matter how one looks at a right-hand screw thread, it remains different from a left-hand screw thread. Therefore, a symmetric object has sinistral and dextral directions arbitrarily defined by the position of the observer, while an asymmetric object that shows chirality may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod Shell
The gastropod shell is part of the body of many gastropods, including snails, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium storage. Some gastropods appear shell-less (slugs) but may have a remnant within the mantle, or in some cases the shell is reduced such that the body cannot be retracted within it (semi-slug). Some snails also possess an operculum that seals the opening of the shell, known as the Aperture (mollusc), aperture, which provides further protection. The study of mollusc shells is known as conchology. The biological study of gastropods, and other molluscs in general, is malacology. Shell morphology terms vary by species group. Shell layers The gastropod shell has three major layers secreted by the Mantle (mollusc), mantle. The calcareous central layer, ostracum, is typically made of calcium carbonate (CaCO3) precipitated into an organic matrix ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dextral Shear
Sinistral and dextral, in some scientific fields, are the two types of chirality ("handedness") or relative direction. The terms are derived from the Latin words for "left" (''sinister'') and "right" (''dexter''). Other disciplines use different terms (such as Dextrorotary, dextro- and Laevorotary, laevo-rotary in Chirality (chemistry), chemistry, or Clockwise#Usage, clockwise and anticlockwise in Chirality (electromagnetism), physics) or simply use left and right (as in Anatomical terms of location#Directional terms, anatomy). Relative direction and chirality are distinct concepts. Relative direction is from the point of view of the observer; a completely symmetric object has a left side and a right side, from the observer's point of view, if the top and bottom and direction of observation are defined. Chirality, however, is observer-independent: no matter how one looks at a right-hand screw thread, it remains different from a left-hand screw thread. Therefore, a symmetric objec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chirality
Chirality () is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from its mirror image; that is, it cannot be superposed (not to be confused with superimposed) onto it. Conversely, a mirror image of an ''achiral'' object, such as a sphere, cannot be distinguished from the object. A chiral object and its mirror image are called '' enantiomorphs'' (Greek, "opposite forms") or, when referring to molecules, ''enantiomers''. A non-chiral object is called ''achiral'' (sometimes also ''amphichiral'') and can be superposed on its mirror image. The term was first used by Lord Kelvin in 1893 in the second Robert Boyle Lecture at the Oxford University Junior Scientific Club which was published in 1894: Human hands are perhaps the most recognized example of chirality. The left hand is a non-superposable mirror ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jeremy (snail)
Jeremy was a left-coiled garden snail studied by researchers from the University of Nottingham. The snail had a rare condition that caused its shell to coil to the left; in most snails the shell coils to the right. It was hoped that the condition would be due to a mutation, and that genes identified from this snail and its offspring would help scientists unlock genetic markers in humans and other animals. At first it was thought to be a rare genetic mutation, although later work revealed that it was likely due to an accident in early development. Jeremy was named after the left-wing British Labour politician Jeremy Corbyn, on account of it being a " lefty" snail, but also due to Corbyn's reported love of gardening. The snail became famous worldwide after a public appeal to find other left-coiled snails for a mate. Jeremy had 56 offspring and died on 11 October 2017, aged "at least two" years. Life A retired scientist found Jeremy in southwest London. He contacted the Univer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphidromus Perversus
''Amphidromus perversus'' is a species of air-breathing land snail, a Terrestrial animal, terrestrial pulmonate gastropod mollusc in the family Camaenidae. ''Amphidromus perversus'' is the type species of the genus ''Amphidromus'', by the subsequent designation of Eduard von Martens (1860). Subspecies * ''Amphidromus perversus butoti'' Laidlaw & Solem, 1961 * ''Amphidromus perversus kadatuaensis'' Dharma, 2007 * ''Amphidromus perversus emaciatus'' (von Martens, 1867) (uncertain > taxon inquirendum, based on invalid original name; no replacement name has been proposed) * ''Amphidromus perversus natunensis'' Fulton, 1896 * ''Amphidromus perversus perversus'' (Carl Linnaeus, Linnaeus, 10th edition of Systema Naturae, 1758) * ''Amphidromus perversus siglerae'' Thach, 2018 ;Synonyms: * ''Amphidromus perversus melanomma'' (Pfeiffer, 1852): synonym of ''Amphidromus melanomma'' (L. Pfeiffer, 1852) * ''Amphidromus perversus rufocinctus'' Fruhstorfer, 1905: synonym of ''Amphidromus perv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flatfish
A flatfish is a member of the Ray-finned fish, ray-finned demersal fish Order (biology), suborder Pleuronectoidei, also called the Heterosomata. In many species, both eyes lie on one side of the head, one or the other migrating through or around the head during development. Some species face their left sides upward, some face their right sides upward, and others face either side upward. The most primitive members of the group, the Threadfin, threadfins, do not resemble the flatfish but are their closest relatives. Many important food fish are in this order, including the flounders, sole (fish), soles, turbot, plaice, and halibut. Some flatfish can camouflage themselves on the ocean floor. Taxonomy Due to their highly distinctive morphology, flatfishes were previously treated as belonging to their own order, Pleuronectiformes. However, more recent taxonomic studies have found them to group within a diverse group of nektonic marine fishes known as the Carangiformes, which also inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strike Slip Fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults. Energy release associated with rapid movement on active faults is the cause of most earthquakes. Faults may also displace slowly, by aseismic creep. A ''fault plane'' is the plane that represents the fracture surface of a fault. A '' fault trace'' or ''fault line'' is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geological maps to represent a fault. A ''fault zone'' is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laterality
The term laterality refers to the preference most humans show for one side of their Human body, body over the other. Examples include Handedness, left-handedness/right-handedness and left/right-footedness; it may also refer to the primary use of the left or right hemisphere in the brain. It may also apply to animals or plants. The majority of tests have been conducted on humans, specifically to determine the effects on language. Human Most humans are right-handed. Many are also right-sided in general (that is, they prefer to use their right human eye, eye, right foot and right ear if forced to make a choice between the two). The reasons for this are not fully understood, but it is thought that because the left cerebral hemisphere of the brain controls the right side of the body, the right side is generally stronger; it is suggested that the Lateralization of brain function, left cerebral hemisphere is dominant over the right in most humans because in 90–92% of all humans, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anatomical Terms Of Location
Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and axes. The meaning of terms that are used can change depending on whether a vertebrate is a biped or a quadruped, due to the difference in the neuraxis, or if an invertebrate is a non-bilaterian. A non-bilaterian has no anterior or posterior surface for example but can still have a descriptor used such as proximal or distal in relation to a body part that is nearest to, or furthest from its middle. International organisations have determined vocabularies that are often used as standards for subdisciplines of anatomy. For example, '' Termi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dexter And Sinister
''Dexter'' and ''sinister'' are terms used in heraldry to refer to specific locations in an Escutcheon (heraldry), escutcheon bearing a coat of arms, and to the other elements of an Achievement (heraldry), achievement. ''Dexter'' (Latin for 'right') indicates the right-hand side of the shield, as regarded by the bearer, i.e. the bearer's proper right, and to the left as seen by the viewer. ''Sinister'' (Latin for 'left') indicates the left-hand side as regarded by the bearer – the bearer's proper left, and to the right as seen by the viewer. In vexillology, the terms ''Glossary of vexillology, hoist'' and ''Glossary of vexillology, fly'' are preferred, although these are not direct equivalents, as their meaning varies with the direction in which the flag is flying. Significance The dexter side is considered the side of greater honour, for example when Impalement (heraldry), impaling two arms. Thus, by tradition, a husband's arms occupy the dexter half of his shield, his wif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastropod
Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and from the land. There are many thousands of species of sea snails and sea slug, slugs, as well as freshwater snails, freshwater limpets, land snails and slugs. The class Gastropoda is a diverse and highly successful class of mollusks within the phylum Mollusca. It contains a vast total of named species, second only to the insects in overall number. The fossil history of this class goes back to the Furongian, Late Cambrian. , 721 family (taxonomy), families of gastropods are known, of which 245 are extinct and appear only in the fossil record, while 476 are currently neontology, extant living fossil, with or without a fossil record. Gastropoda (previously known as univalves and sometimes spelled "Gasteropoda") are a major part of the phylum Mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shear Zone
In geology, a shear zone is a thin zone within the Earth's crust or upper mantle that has been strongly deformed, due to the walls of rock on either side of the zone slipping past each other. In the upper crust, where rock is brittle, the shear zone takes the form of a fracture called a Fault (geology), fault. In the lower crust and mantle, the extreme conditions of pressure and temperature make the rock ductile. That is, the rock is capable of slowly deforming without fracture, like hot metal being worked by a blacksmith. Here the shear zone is a wider zone, in which the ductile rock has slowly flowed to accommodate the relative motion of the rock walls on either side. Because shear zones are found across a wide depth-range, a great variety of different rock types with their characteristic structures are associated with shear zones. General introduction A shear zone is a zone of strong deformation (with a high strain rate) surrounded by rocks with a lower state of Deforma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
