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Gr. 9 Sc: Pesky Harmonics
I have received an off-line message from Mr. Hernan Toro of the Universidad
Pontificia Bolivariana in which the following points are made. Dr. Toro is
an electronics engineer. I have asked for, and been given, permission to
quote from his message. In giving permisssion Mr. Toro asked that I add:
"Mr. Toro said they were conjectures."
1. The long wave lengths that come with low frequencies would be so much
longer than the thickness of any lining of a hadrosaur's airway that the
difference between the real situation and my model can be ignored.
2. Any vocalization would probably include high frequency harmonics which
would be detected by predators. However, it is possible that these higher
frequencies would be dampened by the lining so that predators could not hear
them after all.
I (Della) have been re-reading some of Dr. David Weishampel's work and I
note that in Parasaurolophus the presence of lateral diverticula can cause
cancellation of some of the higher harmonics. Also, I have read in several
places now that low frequencies travel greater distances than high
frequencies. If Parasaurolophus used vocalizations for long distance
communication, maybe I don't have a problem. If I can put these ideas
together with Mr. Toro's idea, maybe I can eliminate those pesky high
Does anyone have any reaction to these comments?