asymmetry
Asymmetry is side difference . Asymmetry as the opposite of symmetry is only spoken of if there are also symmetrical shapes in the respective area.
medicine
In medicine, asymmetry is used when parts of the body in pairs, such as eyes, ears or limbs, differ significantly from one another in terms of shape, size or position, or when the sides of the body are significantly different compared to the halves reflected on the median plane .
Although humans belong to the bilateria or bilateral animals, their bodies are not built on the same side. This can be seen in unpaired internal organs such as the heart , which are not in the middle but on one side (lateralization). The typical left-right asymmetry of their position is determined by signal proteins (e.g. Nodal ) in embryogenesis . The ontogenetic development very seldom leads to deviating positions of organs or transpositions of vessels ( heterotaxia ), possibly with a mirror image of the position ( situs inversus ); A development process without a break in symmetry ( isomerism ) is extremely rare .
The paired structures are created bilaterally symmetrically. However, if you take a closer look, most of them are not designed strictly symmetrically in the following, but usually show lateral differences. Not only are the two auricles slightly different in shape and their distances from the head differ by an average of 2 mm. Characteristically, the face also shows a left half that is different from the right. In most cases, neither arms nor both legs are exactly the same length. Likewise, they are not equally strong, and one side is preferred for certain movement patterns . The situation is similar with parts of the brain that can anatomically differ from one side to the other and, in some regions, are also lateralized according to functional preference .
A symmetry in body structure can therefore only be spoken of with certain restrictions and in relation to an abstract model such as a building plan. For the whole body it is not given, even in exceptional cases.
mathematics
In mathematics, a relation that does not meet the condition for symmetry is called a non-symmetric relation , and one that also fulfills the conditions for asymmetry is called an asymmetric relation .
The term antisymmetry must be distinguished from this ; even an antisymmetric relation cannot be symmetric.
mechanics
In mechanics , asymmetry often has disadvantages, for example in the case of unequal loading by external forces . In the construction industry , one also tries often to avoid asymmetrical construction methods. For example, the effects of earthquakes , but also of wind forces on symmetrical high-rise buildings, are somewhat lower; this property is particularly important when building foundations .
For some applications, however, asymmetry is intentionally created, such as with the mechanical eccentric , with certain applications of the lever law or with the dipped beam of car headlights.
Communications engineering
In communications engineering jargon , asymmetrical signal transmission is often referred to as "asymmetrical" or "asymmetrical" for short. For example, unbalanced cable means a cable for unbalanced signal transmission . The term “asymmetrical” is misleading in this context, as even a slight deviation from perfect symmetry (geometry) is called “asymmetry”. In communications engineering, however, what is meant is asymmetrical signal transmission in which an alternating voltage is transmitted that is related to a ground potential . A symmetrical signal transmission with disturbed symmetry can also be referred to as asymmetrical, there being a significant difference to asymmetrical signal transmission.
Cryptography
In cryptography, encryption systems in which both sides - sender and recipient - need the same key are called symmetrical. In contrast, there are encryption systems in which the sender and recipient use different keys, the asymmetrical cryptosystems .
chemistry
In chemistry , chiral (optically active) molecules are called asymmetric centers (better: stereogenic centers), especially in the case of carbon compounds. In so-called chiral centers , for example, a carbon atom has four different substituents . With the help of the Fischer rules or the CIP system, such organic molecules can be assigned unambiguous names that clearly describe the spatial (three-dimensional) structure.
art
In art , asymmetry tends to attract more interest than mirror-like similarity. A painting or photo, for example, often appears flat when the subject is placed exactly in the middle. A diagonal in the foreground also enlivens almost every graphic , as can often be seen in linoleum or woodcuts .
Even with the stage design or in the music , more attention or tension can be achieved if a structure is not exactly mirror-symmetrical .
While in the Baroque a creative will to create a cross-genre correlates forms and emphasizes central elements through symmetrical arrangements, in the subsequent Rococo period, asymmetrical and irregular shapes become the characteristic design feature for ornamental decorations.
In general, for many topics in art, as well as in the design of facades, displays, squares, parks, gardens, etc., a symmetrical room layout is preferred, but a division that comes close to the golden ratio (about 5: 8).
Economic theory
The goal of the private or commercial sale , it is either profit to achieve or avoid potential losses. For this purpose, asymmetrical information is sought in the communication with the potential buyer with the help of sales psychology. The buyer should only apparently have a choice, ideally between the alternatives offered by the provider. The subjects of asymmetrical information display are regularly advertising , sales talks and contract negotiations.
Social sciences
One speaks of power asymmetry when actors in a situation have structurally unequal opportunities for action. In communication , asymmetrical communication is given when the parties involved in the conversation are not equal. Example: Conflict of interest between a manager and a subordinate employee.
Compare: Paul Watzlawick | cybernetics
Linguistics / semiotics
In linguistics, too, there is much discussion about the asymmetrical nature of linguistic signs.
Web links
Remarks
- ↑ See SI Karcevskij: Du dualisme assymétrique du signe linguistique. In: Znakolog 6-7 (1994/95), Trier 1996, 19-26 (from the French by Heinrich Pfandl under the title: On the asymmetrical dualism of the linguistic sign).