A qualitative mathematical model of a circadian rhythm in crayfish.

Yabo Wu

Biological rhythm is an very important phenomenon in organisms. Many
mathematical models have been used to simulate this oscillatory behavior.
In my presentation, I'm going to introduce a qualitative mathematical
model on a circadian rhythm in crayfish, based on Miguel Lara-Aparicio and
Santiago Lopes De Medrano's work. This model consists of two coupled Van
Der Pol like oscillator in which a dynamical response is obtained mainly
through an Hopf bifurcation. The hypothetical underlying biological
mechanism is also discussed.



Streptococcus pneumoniae infections

Venita DePuy

Streptococcus pneumoniae is the leading cause of community-acquired
bacterial pneumonia in the United States, and is responsible for an
estimated 1 million worldwide deaths annually.  This talk will discuss
nasopharyngeal carriage, invasive pneumococcal disease, vaccinations, and
competition between serotypes.  Discussion of current research will include
SIS and SIRS models with vaccination, direct and indirect competition, and
serotype replacement issues.