Hückel's rule in organic chemistry, also known as the 4n + 2 rule
Hückel's rule, a method of determining aromaticity in organic molecules
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Behavior (e.g., gathering insulation when it is cold, moving into shade when it is hot)
"Liebermeister's rule" states that in adult febrile tachycardia, pulse-beats increase at a rate of approximately eight beats per minute to each degree Celsius.
In the case of marine crustaceans, it has been proposed that the increase in size with depth occurs for the same reasons as the increase in size with latitude (Bergmann's rule): both trends involve increasing size with decreasing temperature.
In 1909, the entomologist Carlo Emery noted that social parasites among insects (e.g., cleptoparasites) tend to be parasites of species or genera to which they are closely related.
This pattern appears to be an example of Allen's rule and is seen in other New Zealand Pompilids but is less marked in E. insularis due to its greater extent of sexual dimorphism with the males always being more uniformly dark.
It was named after the zoologist Constantin Wilhelm Lambert Gloger, who first remarked upon this phenomenon in 1833 in a review of covariation of climate and avian plumage color.
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However absorption of a certain amount of UV radiation is necessary for the production of certain vitamins, notably vitamin D (see also Osteomalacia).
Hückel method, a method for the determination of energies of molecular orbitals
The Hückel method can be derived from the Ritz method, with a few further assumptions concerning the overlap matrix S and the Hamiltonian matrix H.
Snegov's career in literature was a hard one: being subjected to repression during Stalin's rule, he remained under informal suspicion in later life.
Foster's rule, also known as the Island rule or the Island effect, where island populations of animals change in size
Augustus Matthiessen (1831-1870), British physicist and chemist, notable for Matthiessen's rule.
Kin selection based on Hamiliton’s Rule provides an explanation to the population genetics framework and specifies the patterns of local and family genetic makeup that results in the most favorable outcome.
It was pointed out by Henry Rzepa that the conversion of intermediate 5 to 6 can proceed by either a Hückel or a Möbius transition state.
Edgar Heilbronner had described twisted annulenes which had Möbius topology, but in including the twist of these systems, he concluded that Möbius systems could never be lower in energy than the Hückel counterparts.
According to Hund's rule, each orbital is filled with one electron with parallel spin, avoiding the Coulomb repulsion by filling one orbital with two electrons.
It is widely used, for example, by naval architects to numerically integrate hull offsets and cross-sectional areas to determine volumes and centroids of ships or lifeboats.
Thorson's rule (named after Gunnar Thorson by S. A. Mileikovsky in 1971)