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Biomedical subjects

L E Trainor

Publications and source records attributed to L E Trainor.

5 recordsLinked to original sources
PubMed1992

A stochastic evolutionary model of molecular sequences.

A stochastic evolutionary model of molecular sequences is proposed. The basic forces in evolution are supposed to be mutation and selection. The concept is somewhat similar to Kauffman-Levin's concept of adaptive walks and corresponding analytical expressions have been developed. The selective force is divided into two parts: a slowly-varying part and a rapidly-changing fluctuation. The latter influences the distribution of sequences and results in an equation of motion along the flow line. The former plays a more important role in the emergence of evolutionary order. It is demonstrated that the asymmetry of selective forces would lead to a definite order of the system.

Animals↗
PubMed1989

Geometrical aspects of surface morphogenesis.

This paper is concerned with the morphogenesis of structures which form thin deformable sheets. A general formalism is presented for the deformation of a sheet in the presence of an isotropic local body stress. This formalism leads to a set of equations, based on the theory of shells, in which corrections are made in the geometry due to large deformations. Under certain conditions the equations may be solved to give the surface metric tensor as a function of the local tension. A numerical example based on a simple "threshold" model is also presented.

Elasticity↗
PubMed1989

Diffusion effects in calcium-regulated strain fields.

The Goodwin-Trainor equations for cellular morphogenesis, based on calcium ion regulation of the visco-elastic properties of the cellular cortex, are generalized to the situation where the concentration of calcium ions (free plus bound) is allowed to change locally. A stability analysis is presented which shows that the generalized equations are also stable against perturbations at low and high wave lengths and may, for certain parameter values, develop instabilities at intermediate wave lengths.

Animals↗
PubMed1985

A two vector field model of limb regeneration and transplant phenomena.

We propose a new field description of limb regeneration in developmental biology. Central to our approach is the recognition of the importance of vector fields as descriptors in problems involving polarities or a sense of direction. In limb regeneration these vector fields represent the organisms sense of the distal direction, and its sense of the circumferential ordering of structures. Essentially all experimental results obtained to date are consistent with or explained by the model.

Ambystoma↗