Applied Math Seminar
Fall Quarter 2002
3:15 p.m.
Sloan Mathematics Corner
Building 380, Room 380-C


Friday, November 15, 2002


Charles R. Steele
Division of Mechanics and Computation
Department of Mechanical Engineering
Stanford University

Two topics in Biology: Hearing and Plant Morphogenesis


Abstract:

Hearing is the sense for which the input is perhaps easiest to characterize - air pressure as a function of time. Recent advances toward understanding the middle and inner ear will be discussed. The inner ear provides a real-time fourier analysis of the sound. How this occurs can be explained with an application of asymptotic methods to 3-D fluid-elastic waves. To make it interesting, there is nonlinearity involving a feed-back process that can have instabilities leading to ringing in your ear.

A different topic is the pattern formation in plant growth. It seems likely that Turing's reaction-diffusion theory is not the correct explanation. Instead there is considerable evidence that the mechanism is due to mechanical instability of the growth surface.

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