Hebrew University
 
Please note special time and location!
This week we are blessed with TWO talks  (Ryzhik at 1pm, Yakovenko at
2pm) at our seminar.
The location has changed to Manchester  209   for BOTH  talks.
 
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 Special Jerusalem Analysis and PDEs double seminar
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
First talk by: Lenya Ryzhik (Stanford),
Date: November 24th, 2011.
Time: ((13:00))   13:15  
Place: Manchester 209.
 
Title: Biomixing by chemotaxis and enhancement of biological
reactions.
 
 Abstract: See below.
 
Second talk by: Sergei Yakovenko (Weizmann)
More details, including the abstract, are given in a separate 
announcement.
 
Date and time and place: All as above, but one hour later=14:00
 
Abstract for Lenya Ryzhik's talk:
-------------------------
 
Many processes in biology involve both reactions and chemotaxis. However,
the question of interaction between chemotaxis and reactions  has not yet
been addressed either analytically or numerically. We consider a model
with a single density function involving diffusion, advection, chemotaxis,
and absorbing reaction. The model is motivated by studies of coral
broadcast spawning, where experimental observations of the efficiency of
fertilization rates significantly exceed the data obtained from numerical
models that do not take chemotaxis (attraction of sperm gametes by a
chemical secreted by egg gametes) into account. We prove that in the
framework of our model, chemotaxis plays a crucial role. There is a rigid
limit to how much the fertilization efficiency can be enhanced if there is
no chemotaxis but only advection and diffusion. On the other hand, when
 chemotaxis is present, the fertilization rate can be arbitrarily close to
being complete provided that the chemotactic attraction is sufficiently
strong. This is a joint work with Sasha Kiselev.
 
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Technion Math Net-2 (TECHMATH2)
Editor: Michael Cwikel   <techm@math.technion.ac.il> 
Announcement from: Dan Mangoubi   <mangoubi@math.huji.ac.il>