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supersonic sauropods



Just got a copy of Mhyrvold and Currie 1997, Paleobiology 23(4): 393-409,
"Supersonic sauropods? Tail dynamics in the diplodocids."  An interesting
read.

A question for the authors if they're out there: How did you incorporate
damping into your model? I don't see it anywhere. Bullwhips aside,
muscle-tendon contractile units today are generally modeled using
"spring-dashpot" theory as an abstraction (most basic muscle textbooks and
physiology courses will discuss this). I think I can see the spring part,
but was there any damping in the model?

This really matters, IMHO. Applying 20-50 thousand N-m torque at the base
of the tail doesn't mean it's transmitted 100% to the tip (or am I wrong?)
-- damping due to energy dissipation in cartilages and other soft tissues
will take its toll. Or maybe I'm missing something here, or have
misremembered my comparative physiology classwork. I'll reread the paper
but I couldn't find any discussion of this assumption in it.

I thought I'd ask, with all due respect to the authors of course. It's
always nice to see people testing functional hypotheses using biomechanics
rather than telling functional stories using gestalt impressions of the
inner workings of biology.

                        John R. Hutchinson
                 Department of Integrative Biology
                  3060 Valley Life Sciences Bldg.
                University of California - Berkeley
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         http://ucmp1.berkeley.edu/people/jrh/homepage.html