Saturday, November 4, 2006 - 10:40am - 11:40am
- Transmission and control of seasonal and pandemic influenza
Gerardo Chowell (Los Alamos National Laboratory)
Recurrent epidemics of influenza are observed seasonally around the world
with considerable health and economic consequences. Major changes in the
influenza virus composition through antigenic shifts can give rise to
pandemics. The reproduction number provides a measure of the
transmissibility of influenza. We estimated the reproduction number across
influenza seasons in the United States, France, and Australia for the last
3 decades. In regards to pandemic influenza, we estimated the reproduction
number for the first two epidemic waves during the 1918 influenza pandemic
in Geneva, Switzerland. I will discuss the public health implications of
our findings in terms of controlling regular influenza epidemics and an
influenza pandemic of comparable magnitude to that of 1918.
- Registration of 4D CT lung images
Edward Castillo (Rice University)
In collaboration with Guerrero et al from MD Anderson Cancer Center,
we are developing a new method for accurate registration of 4D CT lung
images which accounts for: (1) the compressible nature of the lungs,
(2) noise in the images, (3) the high computational workload required to
register 4D CT image sets.
In order to account for lung compressibility, voxel displacement is modeled
by the conservation of mass equation. Secondly, the
effects of noise are alleviated by applying the local-global approach of
Weickert et al. to the conservation of mass setting. Finally, the resulting large scale linear
systems are solved using a parallelizable, preconditioned conjugate gradient algorithm.
The new method has been implemented in serial and tested on two dimensional
sythetic images with promising results.
- Epidemic spread in populations at demographic equilibrium
Karen Ríos-Soto (Cornell University)
We introduce an integrodifference equation model to study the
spatial spread of epidemics through populations with overlapping and non-
overlapping epidemiological generations. Our focus is on the existence
of travelling wave solutions and their minimum asymptotic speed of
propagation c*. We contrast the results here with similar work carried
out in the context of ecological invasions. We illustrate the theoretical
results numerically in the context of SI (susceptible-infected) and SIS
(susceptible-infected-susceptible) epidemic models.