Modelling dynamics of T cells in Type 1 Diabetes

Speaker: 

Professor Leah Keshet

Institution: 

UBC

Time: 

Friday, February 2, 2007 - 3:00pm

Location: 

MSTB 254

Type 1 diabetes (T1D) is an autoimmune disease in which immune cells
target and kill the insulin-secreting pancreatic beta cells.
Recent investigation of diabetes-prone (NOD) mice reveals large cyclic
fluctuations in the levels of T cells (cells of the adaptive
immune system) weeks before the onset of the disease. We extend
a previous mathematical model for T-cell dynamics to account for the
gradual killing of beta cells, and show how such cycles can arise
as a natural consquence of feedback between self-antigen and T-cell
populations. The model has interesting nonlinear dynamics
including Hopf and homoclinic bifurcations in biologically reasonable
regimes of parameters. The model fits into a larger program of
investigation of type 1 diabetes, and suggests experimental tests.

Bodies interacting with and through fluids

Speaker: 

Professor Mike Shelley

Institution: 

Courant Institute

Time: 

Thursday, February 15, 2007 - 4:00pm

Location: 

MSTB 254

The interaction of flowing fluids with free bodies -- sometimes
compliant, sometimes active, sometimes multiple -- constitutes a class
of beautiful dynamic boundary problems that are central to biology and
engineering. Examples range from how organisms locomote in fluids
(which depends strongly on scale) to how non-Newtonian stresses
develop in complex liquids (strongly dependent on the nature of
fluidic microstructure). I will discuss several interesting examples,
emphasizing how they are formulated mathematically so as to yield
models tractable for analysis or simulation, and show how this work
has interacted with experimental studies.

Can one make objects invisible?

Speaker: 

Professor Gunther Uhlmann

Institution: 

University of Washington

Time: 

Thursday, February 22, 2007 - 4:00pm

Location: 

MSTB 254

The subject of invisibility has fascinated people for thousands
of years. There has recently been considerable theoretical and practical
progress in understanding how to cloak objects. We will discuss some of
the recent work on the subject of invisibility which involves using
singular electromagnetic parameters, or singular Riemannian metrics.

Computational surface partial differential equations

Speaker: 

Professor Charlie Elliott

Institution: 

University of Sussex

Time: 

Thursday, March 15, 2007 - 4:00pm

Location: 

MSTB 254

Partial differential equations on and for evolving surfaces occur in many applications.
For example, traditionally they arise naturally in fluid dynamics and materials
science and more recently in the mathematics of images.
In this talk we describe computational approaches to the formulation and
approximation of transport and diffusion of a material quantity on an
evolving surface.
We also have in mind a surface which not only evolves in the normal direction
so as to define the surface evolution but also has a tangential velocity
associated with the motion of material points in the surface which advects material
quantities such as heat or mass.This is joint work with G. Dziuk

Universality for mathematical and physical systems

Speaker: 

Professor Percy Deift

Institution: 

Courant Institute

Time: 

Thursday, November 2, 2006 - 4:00pm

Location: 

MSTB 254

All physical systems in equilibrium obey the laws of
thermodynamics. In other words, whatever the precise nature of the
interaction between the atoms and molecules at the microscopic level,
at the macroscopic level, physical systems exhibit universal behavior in
the sense that they are all governed by the same laws and formulae of
thermodynamics.

The speaker will recount some recent history of universality ideas in
physics starting with Wigner's model for the scattering of neutrons
off large nuclei and show how these ideas have led mathematicians to
investigate universal behavior for a variety of mathematical systems.
This is true not only for systems which have a physical origin, but also
for systems which arise in a purely mathematical context such as the
Riemann hypothesis, and a version of the card game solitaire called
patience sorting.

The Distribution Functions of Random Matrix Theory

Speaker: 

Professor Craig Tracy

Institution: 

UC Davis

Time: 

Thursday, November 30, 2006 - 4:00pm

Location: 

MSTB 254

It is now believed, but proved only in a few cases, that the distribution
functions
of random matrix theory are universal for a wide class of stochastic
problems in combinatorics,
growth processes, and statistics. These developments will be surveyed.
No prior knowledge
of random matrix theory will be assumed.

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