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Professor of Biology and Mathematics
H. weiss

I am a Biomathematican and very recently moved to Penn State from Georgia Tech (I also had appointments at Emory in Public Health and PBEE). Bacteria and their viruses (phages) provide a way to study ecological and evolutionary processes in real time under the well-controlled laboratory conditions. Many of the questions that our group studies lie at the intersection of fundamental science and improving human and animal health. We develop new approaches to mathematical modeling to better understand the role of the physical structure in how bacteria grow and evolve. To complement this computational work, we work closely with microbiologists, biochemists, virologists, physicians, veterinarians, etc. and combine mathematical models with experiments. In recent years I have taught courses in virus dynamics, population genetics, dynamics and bifurcations, advanced linear algebra, and stochastic processes.



One of our group’s main research foci is to combine mathematical modeling and laboratory experiments to study how populations and communities of bacteria grow and evolve in physically structured environments, and how to most effectively employ antimicrobials and bacteriophages to eliminate the harmful bugs. The physical structure is particularly critical for the treatment of surface-associated infections (e.g., endocarditis, osteomyelitis,  CF infections). It is not uncommon that such infections are susceptible to an antibiotic, but antibiotic therapy fails. We love to investigate puzzles like this. We also study the perturbation of the gut microbiome by oral antibiotics and try to find ways of speeding recovery to the normal state. Our spatial models consist of PDEs, agent based models, and network models, and we take our numerical analysis seriously.

Another main foci is to find ways to mitigate infectious disease transmission, especially during air travel. In the first phase of our FlyHealthy project, we collaborated with Emory Boeing, Delta, TSA, and the J. Craig Venter Institute to quantify several key drivers of direct transmission of large droplet mediated respiratory infectious diseases (e.g., Influenza) on transcontinental US flights, as well as study the airplane cabin microbiome. We are hoping, in the not too distant future, to carry out a similar study for aerosol transmission (TB, Measles, and SARS are all transmitted via aerosols).