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Asymmetry

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	Topics Asymmetry Topic Home Asymmetry is the absence of, or a violation of, a symmetrySymmetry Symmetry is a characteristic feature of geometrical shapes, systems, equations, and other real or conceptual objects —t... . Asymmetry in organisms Due to how cellCell (biology) The cell is the structural and functional unit of all living organisms, and is sometimes called the "building block of life.... s divide in organismOrganism In biology and ecology, an organism is a living complex adaptive system of organs that influence each other in such a way t... s, asymmetry in organisms is fairly usual in at least one dimension, with biological symmetrySymmetry (biology) Symmetry in biology is the balanced distribution of duplicate body parts or shapes.... also being common in at least one dimension. Louis PasteurLouis Pasteur Overview Louis Pasteur was a French microbiologist and chemist.... proposed that biological molecules are asymmetric because the cosmic [i.e. physical] forces that preside over their formation are themselves asymmetric. While at his time, and even now, the symmetry of physical processes are highlighted, it is known that there are fundamental physical asymmetries, starting with time. Further, truly fundamental left-right symmetry violation is now known in particle physics (see Parity violation below). Asymmetries useful to the organism Asymmetry and important evolutionary traits, such as the left humanHuman Humans, or human beings, are bipedal primates belonging to the mammalian species *Homo sapiens* under the fami... lungLung The lung is the essential respiration organ in air-breathing vertebrates.... being smaller than the right to make room for the asymmetrical heartHeart Summary The heart is a hollow, muscular organ in vertebrates, responsible for pumping blood through the blood vessels by repeated, r... . HandednessHandedness Handedness is an attribute of human beings defined by their unequal distribution of fine motor skill between the left and ri... is an asymmetry in skill development in people and animals. Training the neural pathways in a skill with one hand (or paw) takes less effort than doing the same with both hands. Nature also provides several examples of handedness in traits that are usually symmetric. The following are examples of animals with obvious left-right asymmetries: Fiddler crabFiddler crab Note: A separate disambiguation page exists for the initials UCA.... s have one big claw and one small claw. The narwhalNarwhal The Narwhal is an Arctic species of cetacean with a body similar to that of a Beluga whale and Irrawaddy Dolphin.... 's tusk is a left incisor which can grow up to 10 feet in length and forms a left-handed helix. FlatfishFlatfish The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciform... have evolved to swim with one side upward, and as a result have both eyes on one side of their heads. Several species of owlOwl An owl is a solitary, mainly nocturnal bird of prey.... s exhibit asymmetries in the size and positioning of their ears, which is thought to help locate prey. Asymmetry as an indicator of unfitness Certain disturbances during the development of the organism, resulting in birth defects. Injuries after cell division that cannot be biologically repaired, such as a lost limbLimb (anatomy) Overview A limb is a jointed, or prehensile , appendage of the human or animal body.... from an accident. Since birth defects and injuries are likely to indicate poor health of the organism, defects resulting in asymmetry often put an animal at a disadvantage when it comes to finding a mate. In particular, a degree of facial symmetryFacial symmetry Facial symmetry is one of a number of traits associated with health, physical attractiveness and beauty of a person or anim... is associated with physical attractiveness, but complete symmetry is both impossible and probably unattractive. Asymmetry in chemistry Certain molecules are chiralChirality (chemistry) The term chiral is used to describe an object which is non-superimposable on its mirror image.... ; that is, they cannot be superposed upon their mirror image. Some sugarFacts About Sugar In general use, non-scientists take "sugar" to mean sucrose, also called "table sugar" or saccharose, a white crystalline solid di... s are chiral: glucoseGlucose Glucose , a monosaccharide , is one of the most important carbohydrates in biology.... (also called dextrose) and fructoseFructose Fructose is a simple sugar found in many foods and one of the three most important blood sugars along with glucose and gal... (sometimes called levulose or invert sugar) are chiral isomers of the same molecule, C₆H₁₂O₆. The word invert comes from the way that sugar syrups rotate plane-polarized light. A sucrose or glucose solution rotates the plane of polarization of the light to the right, while a fructose syrup rotates it strongly to the left. Asymmetry in physics Asymmetry arises in physics in a number of different realms. Thermodynamics ThermodynamicsThermodynamics Thermodynamics is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical ... is asymmetrical in timeEntropy (arrow of time) Entropy is the only quantity in the physical sciences that "picks" a particular direction for time, sometimes called an arrow of t... : the entropyEntropy In thermodynamics, entropy, symbolized by S, is a state function of a thermodynamic system defined by the differential q... in a closed system can only increase with time. A consequence of this is Clausius' Second Law, which states that there is no thermodynamic process whose sole effect is to extract a quantity of heat from a colder reservoir and deliver it to a hotter reservoir. Particle physics SymmetrySymmetry in physics Symmetry in physics refers to various features of a physical system that can be said to exhibit the property of symmetry &md... is one of the most powerful tools in particle physicsParticle physics Particle physics is a branch of physics that studies the elementary constituents of matter and radiation, and the interactio... , because it has become evident that practically all laws of nature originate in symmetries. Violations of symmetry therefore present theoretical and experimental puzzles that lead to a deeper understanding of nature. Asymmetries in experimental measurements also provide powerful handles that are often relatively free from background or systematic uncertainties. Parity violation Main article: parity (physics)Parity (physics) In physics, a parity transformation is the simultaneous flip in the sign of all spatial coordinates:... Until the 1950s, it was believed that fundamental physics was left-right symmetric; i.e., that interactions were invariant under parityParity (physics) In physics, a parity transformation is the simultaneous flip in the sign of all spatial coordinates:... . Although parity is conserved in electromagnetismElectromagnetism Electromagnetism is the physics of the electromagnetic field; a field encompassing all of space which exerts a force on part... , strong interactions and gravity, it turns out to be violated in weak interactions. The Standard ModelStandard Model The Standard Model of particle physics is a theory which describes the strong, weak, and electromagnetic fundamental forces,... incorporates parity violation by expressing the weak interaction as a chiralChirality (physics) A phenomenon is said to be chiral if it is not identical to its mirror image.... gauge interaction. Only the left-handed components of particles and right-handed components of antiparticles participate in weak interactions in the Standard Model. A consequence of parity violation in particle physics is that neutrinos have only been observed as left-handed particles (and antineutrinos as right-handed particles). In 1956-1957 Chien-Shiung WuChien-Shiung Wu Chien-Shiung Wu was a Chinese American physicist with an expertise in radioactivity.... , E. Ambler, R. W. Hayward, D. D. Hoppes, and R. P. Hudson found a clear violation of parity conservation in the beta decay of cobalt-60. Simultaneously, R. L. GarwinRichard Garwin Richard L. Garwin, is an American physicist.... , Leon Lederman, and R. Weinrich modified an existing cyclotron experiment and immediately verified parity violation. CP violation Main article: CP-violationCP-violation In physics, and specifically particle physics, CP violation is a violation of the postulated CP symmetry of th... After the discovery of the violation of parity in 1956-57, it was believed that the combined symmetry of parity (P) and simultaneous charge conjugation (C), called CP, was preserved. For example, CP transforms a left-handed neutrino into a right-handed antineutrino. In 1964, however, James CroninJames Cronin James Watson Cronin is an American nuclear physicist.... and Val Fitch provided clear evidence that CP symmetry was also violated in an experiment with neutral kaons. CP violation is one of the necessary conditions for the generation of a baryon asymmetry in the universe. Combining the CP symmetry with simultaneous time reversalT-symmetry T-symmetry is the symmetry of physical laws under a time reversal transformation—... (T) produces a combined symmetry called CPT symmetryCPT symmetry CPT symmetry is a fundamental symmetry of physical laws under transformations that involve the inversions of charge, parity ... . CPT symmetry must be preserved in any Lorentz invariant local quantum field theoryQuantum field theory Quantum field theory is the quantum theory of fields.... with a HermitianSelf-adjoint operator Overview On a finite-dimensional inner product space, a self-adjoint operator is one that is its own adjoint, or, equivalently, one w... HamiltonianHamiltonian (quantum mechanics) Overview The quantum Hamiltonian is the physical state of a system, which may be characterized as a ray in an abstract Hilbert space ... . As of 2006, no violations of CPT symmetry have been observed. Baryon asymmetry of the universe Main article: baryogenesisBaryogenesis In physical cosmology, baryogenesis is the generic term for hypothetical physical processes that produced an asymmetry betwe... The baryons (i.e., the protons and neutrons and the atoms that they comprise) observed in the universe are overwhelmingly matterMatter In physics, matter is commonly defined as the substance of which physical objects are composed, not counting the contributio... as opposed to anti-matterAnti-Matter Anti Matter was the first single off the album Take Me To Your Leader by MF DOOM under the Monsta Island Czars aliases Ki... . This asymmetry is called the baryon asymmetryBaryon asymmetry The baryon asymmetry problem in astrophysics refers to the apparent fact that the baryons in the universe which have been ob... of the universe. Isospin violation IsospinIsospin In physics, and specifically, particle physics, isospin is a symmetry of the strong interaction as it applies to the interac... is the symmetry transformation of the weak interactions. The concept was first introduced by Werner HeisenbergWerner Heisenberg Werner Karl Heisenberg was a celebrated German physicist and Nobel laureate, one of the founders of quantum mechanics, and ... in nuclear physicsNuclear physics Nuclear physics is the branch of physics concerned with the nucleus of the atom.... based on the observations that the masses of the neutronNeutron In physics, the neutron is a subatomic particle with no net electric charge and a mass of 939.573 MeV/c .... and the protonProton In physics, the proton is a subatomic particle with an electric charge of one positive fundamental unit , a diameter of abo... are almost identical and that the strength of the strong interactionStrong interaction The strong interaction or strong force is today understood to represent the interactions between quarks and gluons as ... between any pair of nucleons is the same, independent of whether they are protons or neutrons. This symmetry arises at a more fundamental level as a symmetry between up-type and down-type quarkQuark In particle physics, quarks are one of the two basic constituents of matter .... s. Isospin symmetry in the strong interactions can be considered as a subset of a larger flavor symmetry group, in which the strong interactions are invariant under interchange of different types of quarks. Including the strange quarkStrange quark The strange quark is a second-generation quark with a charge of -e and a strangeness of -1.... in this scheme gives rise to the Eight-fold WayFacts About Eightfold way (physics) In physics, the Eightfold Way is a term coined by American physicist Murray Gell-Mann for a theory organizing subatomic bary... scheme for classifying mesons and baryons. Isospin is violated by the fact that the masses of the up and down quarks are different, as well as by their different electric charges. Because this violation is only a small effect in most processes that involve the strong interactions, isospin symmetry remains a useful calculational tool, and its violation introduces corrections to the isospin-symmetric results. Asymmetries in collider experiments Because the weak interactionWeak interaction The weak interaction is one of the four fundamental interactions of nature.... s violate parity, colliderCollider A collider is a type of a particle accelerator with two opposite beams of the particles.... processes that can involve the weak interactions typically exhibit asymmetries in the distributions of the final-state particles. These asymmetries are typically sensitive to the difference in the interaction between particles and antiparticles, or between left-handed and right-handed particles. They can thus be used as a sensitive measurement of differences in interaction strength and/or to distinguish a small asymmetric signal from a large but symmetric background. A forward-backward asymmetry is defined as A_FB=(N_F-N_B)/(N_F+N_B), where N_F is the number of events in which some particular final-state particle is moving "forward" with respect to some chosen direction (e.g., a final-state electron moving in the same direction as the initial-state electron beam in electron-positron collisions), while N_B is the number of events with the final-state particle moving "backward". Forward-backward asymmetries were used by the LEP experiments to measure the difference in the interaction strength of the Z boson between left-handed and right-handed fermions, which provides a precision measurement of the weak mixing angle. A left-right asymmetry is defined as A_LR=(N_L-N_R)/(N_L+N_R), where N_L is the number of events in which some initial- or final-state particle is left-polarized, while N_R is the corresponding number of right-polarized events. Left-right asymmetries in Z boson production and decay were measured at the Stanford Linear ColliderStanford Linear Collider The Stanford Linear Collider was a linear accelerator that collided electrons and positrons at the Stanford Linear Accelerat... using the event rates obtained with left-polarized versus right-polarized initial electron beams. Left-right asymmetries can also be defined as asymmetries in the polarization of final-state particles whose polarizations can be measured; e.g., tau leptonTau lepton The tau lepton is a negatively charged elementary particle with a lifetime of 3×10−13 seconds and a mass of 1777... s. A charge asymmetry or particle-antiparticle asymmetry is defined in a similar way. This type of asymmetry has been used to constrain the parton distribution functionsParton (particle physics) In particle physics, the parton was a hypothetical fundamental particle considered, in the "parton model" of strong interact... of protons at the TevatronTevatron Summary Tevatron is a circular particle accelerator at the Fermi National Accelerator Laboratory in Batavia, Illinois and is current... from events in which a produced W boson decays to a charged lepton. The asymmetry between positively and negatively charged leptons as a function of the direction of the W boson relative to the proton beam provides information on the relative distributions of up and down quarks in the proton. Particle-antiparticle asymmetries are also used to extract measurements of CP violation from B mesonMeson In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin.... and anti-B meson production at the BaBarBaBar experiment In the field of particle physics BaBar is an international collaboration of more than 550 physicists and engineers investiga... and BelleBelle experiment The Belle Experiment is a particle physics experiment conducted by the Belle Collaboration, an international collaboration o... experiments. Lexical asymmetry Asymmetry is also relevant to grammarGrammar Grammar is the study of rules governing the use of language.... and linguisticsLinguistics Linguistics is the scientific study of human language.... , especially in the contexts of lexical analysisLexical analysis Lexical analysis is the processing of an input sequence of characters to produce, as output, a sequence of symbols called "l... and transformational grammarTransformational grammar Transformational grammar is a broad term describing grammars which have been developed in a Chomskian tradition.... . Enumeration example: In EnglishFacts About English language English is a widely distributed language that originated in England but is now the primary language in numerous countries.... , there are grammatical rules for specifying coordinate items in an enumeration or series. Similar rules exist for programming languageProgramming language A programming language is an artificial language that can be used to control the behavior of a machine, particularly a compu... s and mathematical notationMathematical notation Mathematical notation is used in mathematics, and throughout the physical sciences, engineering, and economics.... . These rules vary, and some require lexical asymmetry to be considered grammatically correct. For example in standard written English: We sell domesticated cats, dogs, and goldfish.### in-line asymmetric and grammatical We sell domesticated animals (cats, dogs, goldfish). ### in-line symmetric and grammatical We sell domesticated animals (cats, dogs, goldfish,). ### in-line symmetric and ungrammatical We sell domesticated animals: ### outline symmetric and grammatical - cats - dogs - goldfish See also Information asymmetryInformation asymmetry In economics, information asymmetry occurs when one party to a transaction has more or better information than the other pa... Asymmetric multiprocessingAsymmetric multiprocessing ASMP stands for Asymmetric Multiprocessing....