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Three examples of Turing patterns Six stable states from Turing equations, the last one forms Turing patterns. The Turing pattern is a concept introduced by English mathematician Alan Turing in a 1952 paper titled "The Chemical Basis of Morphogenesis" which describes how patterns in nature, such as stripes and spots, can arise naturally and autonomously from a homogeneous, uniform state.
While theory in colloquial usage may denote a hunch or conjecture, a scientific theory is a set of principles that explains an observable phenomenon in natural terms. [127] [128] "Scientific fact and theory are not categorically separable", [129] and evolution is a theory in the same sense as germ theory or the theory of gravitation. [130]
Fick's first law relates the diffusive flux to the gradient of the concentration. It postulates that the flux goes from regions of high concentration to regions of low concentration, with a magnitude that is proportional to the concentration gradient (spatial derivative), or in simplistic terms the concept that a solute will move from a region of high concentration to a region of low ...
The Hill equation can be used to describe dose–response relationships, for example ion channel-open-probability vs. ligand concentration. [ 9 ] Dose is usually in milligrams, micrograms , or grams per kilogram of body-weight for oral exposures or milligrams per cubic meter of ambient air for inhalation exposures.
The metabolic theory of ecology (MTE) [1] is the ecological component of the more general Metabolic Scaling Theory [2] and Kleiber's law. It posits that the metabolic rate of organisms is the fundamental biological rate that governs most observed patterns in ecology.
Note that this simple theory predicts that this contribution to the diffusiophoretic motion is always up a salt concentration gradient, it always moves particles towards higher salt concentration. By contrast, the sign of the electric-field contribution to diffusiophoresis depends on the sign of β ζ {\displaystyle \beta \zeta } .
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration , molar concentration , number concentration , and volume concentration . [ 1 ]
The chemical gradient, or difference in solute concentration across a membrane. The electrical gradient, or difference in charge across a membrane. If there are unequal concentrations of an ion across a permeable membrane, the ion will move across the membrane from the area of higher concentration to the area of lower concentration through ...