[Events] MACSI Seminar (today at 4pm)

Sarah.Mitchell Sarah.Mitchell at staffmail.ul.ie
Fri Nov 20 08:00:40 GMT 2009

The department of Mathematics and Statistics invites you to a seminar by
Dr. Daniele Avitabile (Bristol Centre for Applied Nonlinear Mathematics,
University of Bristol, UK): 



Title:  Active Hearing Systems in mosquitoes: from mesoscopic to
macroscopic models


Abstract:  Insects have evolved diverse and delicate morphological
structures in order to capture the inherently low energy of a
propagating sound wave. In mosquitoes, the capture of acoustic energy,
and its transduction into neuronal signals, is assisted by the active
mechanical participation of the scolopidia. We have proposed a simple
mesoscopic mechanistic model of the active amplification in the mosquito
species Toxorhynchites brevipalpis. The model is based on the
description of the antenna as a forced-damped oscillator coupled to a
set of active threads (ensembles of scolopidia) that provide an
impulsive force when they twitch. This twitching is in turn controlled
by channels that are opened and closed if the antennal oscillation
reaches a critical amplitude. The model matches both qualitatively and
quantitatively with recent experiments: spontaneous oscillations,
nonlinear amplification, hysteresis, 2:1 resonances, frequency response,
gain loss due to hypoxia. The numerical simulations also generate new
hypotheses. In particular, the model seems to indicate that scolopidia
located toward the tip of the Johnston's organ are responsible for the
entrainment of the other scolopidia, and that they give the largest
contribution to the mechanical amplification. I will also introduce an
averaging of the mesoscopic model, allowing to describe quantitatively
the neuronal force at a macroscopic scale.



The seminar will take place on Friday 20th November, at 4pm, in A2-002.


If you have any questions regarding this seminar, please direct them to
Sarah Mitchell (061 202259, sarah.mitchell at ul.ie
<mailto:sarah.mitchell at ul.ie> ).  A full list of Seminars for this
semester can be found at: 





Supported by Science Foundation Ireland Mathematics Initiative funding,
MACSI - the Mathematics Applications Consortium for Science and Industry
(www.macsi.ie), centred at the University of Limerick, is dedicated to
the mathematical modelling and solution of problems which arise in
science, engineering and industry in Ireland





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