short talks

Saturday, November 4, 2006 - 10:40am - 11:40am
EE/CS 3-180
  • 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.