Symmetry in locomotor central pattern generators and animal gaits
Article Abstract:
It has been established that any central pattern generator, an intraspinal network of neurons able to generate a rhythmic output, fulfilling all of six assumed conditions must be made up of eight identical cells. There are two forms of symmetry in the network: ipsilateral symmetry, that cyclically and simultaneously permutes cells on both left and right, and contralateral symmetry, that interchanges cells on the left with cells on the right. The model prescribes only the symmetries of the central pattern generator, not the differential equations, but still leads to a number of predictions.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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A gathering of groups
Article Abstract:
It has been possible to apply methods of computer algebra to count and construct all finite groups with 1,000 elements or less. This research highlights the irregularity of the group-theory landscape. Three basic methods are used: the Frattini method, the cyclic-extensions method and the upward-extension method. The first two apply to so-called soluble groups, which can be constructed from components of prime order. The third is used for groups that are not soluble.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2000
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Holes and hot spots
Article Abstract:
The Laplace operator is at the core of classical theories of heat, light, sound, magnetism, gravitation, fluid mechanics and electricity. Krzysztof Burdzy and Wendelin Werner have tackled the so-called hot spots conjecture, showing that the expected answer is wrong, based on physical insight about the geometry of bicycle wheels.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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