Tuesday, January 26

COLLOQUIUM
TIME:  12:00 – 12:50 p.m.
ROOM:  403 NIMBioS Building
SPEAKER: Professor Eunha Shim, Yale University (NIMBioS candidate)
TITLE:  “Antiviral resistance during an influenza pandemic: optimal
antiviral strategies driven by individual and population interest”
ABSTRACT: Planning a response to an outbreak of a pandemic strain of influenza is a public health priority, and antiviral drugs play a critical role in mitigating the influenza pandemic. However, the administration of antivirals has epidemiological and evolutionary repercussions that affect both the individual patient and the population. Although individuals benefits from reduced probability and/or severity of infection, they may experience adverse effects of antivirals. Within the population, antiviral intervention reduces transmission, but also selects for drug resistance. To evaluate how the balance among these factors results in optimal coverage for both the individual and the population, we developed an epidemiological game-theoretic model of pandemic influenza. We parameterize the model with survey data on actual perceptions regarding infection risk, the level of resistance, the efficacy and adverse effects of antivirals, and the willingness to pay for antivirals during pandemic influenza. We find that the demand for antivirals driven by self-interest (i.e. the Nash strategy) during pandemic influenza would likely be far lower than that which would maximize overall utility for the population (i.e. utilitarian strategy), if individuals made decisions based on their beliefs. However, we demonstrate that the discrepancy between the Nash and utilitarian strategies can be brought into alignment to some extent by providing individuals with accurate knowledge about the epidemiology and risk of pandemic influenza. Thus, public education about the infection risk and the level of resistance associated with antivirals may promote antiviral drug use closer to achieve optimal levels for the population.

Wednesday, January 27

ANALYSIS SEMINAR
TIME:  3:35 p.m.
ROOM:  HBB 132
SPEAKER: Professor Ken Stephenson
TITLE:  “Come and watch me circle pack!”
ABSTRACT: I've spent years developing circle packing software so that I can run concrete experiments in complex function theory.  In those years I've become a committed "experimentalist", and I'd like to share some of what I've learned --- not just about complex functions, but about programming and computation, about the culture of modern science, and about mathematics as an enterprise.

In this first seminar, I will run through some experiments involving conformal mapping, finite Blaschke products, harmonic mappings, and random triangulations. This is very visual stuff and should be understandable without any complex analysis background (or interest). Moreover, my subsequent talk(s) will not be about complex analysis as much as they are about the difficulties experimentalists face, both from computers and people.

Thursday, January 28

COLLOQUIUM
TIME:  1:15 – 2:15 p.m.
ROOM:  223-224 University Center
SPEAKER: Professor Xiao Wang, Department of Biomedical Engineering, Boston University (NIMBioS Candidate)
TITLE:  “Programming Gene Regulation: From Synthetic Gene Networks to Cell Differentiation”
ABSTRACT: Synthetic gene networks can be constructed from bottom up with desired properties. However, constructing predictable gene networks with desired functions remains a challenge. It is because of unpredictability of the assembled networks and the lack of well-characterized components. Here I present the bottom-up and diversity-based approaches that combine promoter synthesis and mathematical modeling to quickly construct gene networks with desired properties. In the bottom-up approach, a hybrid promoter is engineered to allow the study of gene regulation under increasingly complex conditions. We develop a stochastic model that quantitatively captures the means and distributions of the expression from the engineered promoter, and show that the model can be extended to reveal some counterintuitive predictions that are confirmed experimentally. In the diversity-based approach, promoters with random strength diversities are synthesized and characterized in parallel. When coupled with mathematical modeling to simulate the network at a whole system level, promoters that are optimal for the intended functions can be selected before the actual network assembly, without the need for post-hoc modifications. This approach will first be demonstrated in yeast by constructing negative feedforward loop networks. Then the method will be used to produce a synthetic gene network that acts as a timer, tunable by component choice. We utilize this network to control the timing of yeast flocculation phenotype, to illustrate a practical application of our approach. The construction of a synthetic cellular counter will also be presented.

Finally, ongoing research on gene regulation networks that are responsible for cell fate determination will be presented. Stem cell differentiation from a pluripotent state to one of many different cell fates is a very important biological manifestation of multistability, the property of having two or more mutually exclusive states over time. Recent works have indicated that this multistability arises from inherently nonlinear dynamical systems. We develop the algorithm to screen for highly connected transcription factor regulation networks that show several stable steady states. Such networks are studied in detail to uncover design principles of gene regulation and roles of stochasticity in cell differentiation. Potential construction of synthetic biology prototypes will also be discussed.

If you are interested in giving or arranging a talk for one of our seminars or colloquiums, please review our calendar.

If you have questions, or a date you would like to confirm, please contact Dr. Steve Wise.

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Past notices:

Seminars from 2008-2009 academic year

Seminars from 2007-2008 academic year

Seminars from 2006-2007 academic year

Seminars from 2005-2006 academic year