Colloquia 2002
Mathematical Biology/Biocomplexity Colloquium
Date:
Wednesday, November 20, 2002
Time: 4:30 PM
Location: 117, Hayes-Healy Hall, Notre Dame
Speaker: Dr. Frithjof Lutscher
Center for Mathematical
Biology, Department of Mathematical and Statistical
Sciences, University of Alberta, Edmonton, AB T6G 2G1, Canada
Host: Mark S. Alber (Mathematics)
Title: Individual behavior and population patterns in Myxobacteria
Abstract:
It is well known that certain cell types and bacteria use long range signaling
to induce
coordinated movement behavior, e.g., chemotaxis. A major question is whether
or not
also short range signaling or local interaction can be the cause of coordinated
movement
behavior and morphogenetic processes. There is strong experimental evidence
that the
rippling behavior observed in Myxobacteria is caused by nearest neighbor
interaction
only. Several mathematical models have been developed which all confirm
that rippling
patterns can emerge from purely local interaction.
As a model problem
for these patterns, we derive and study a one-dimensional
hyperbolic system of Goldstein-Kac type with density dependent coefficients.
Linear
analysis and construction of invariant domains give qualitative conditions
on the coefficient
functions under which the system exhibits traveling wavetrain solutions
which look much
like rippling. The system is also able to produce aggregation. Simulations
of individual
paths show markedly different behavior of cells in the different emerging
population
patterns.
Mathematics/Physics/Biocomplexity Colloquium
Date:
Wednesday, November 13, 2002
Time: 4:30 PM
Location: 117, Hayes-Healy Hall, Notre Dame
Speaker: Joel L.
Lebowitz
Rutgers, The State University of New Jersey
A prolific researcher
in equilibrium and nonequilibrium statistical mechanics, Joel Lebowitz,
together
with Elliot Lieb, proved in 1970 the existence of the thermodynamic limit
for Coulomb systems. In
recent years, he has contributed to our understanding of nonequilibrium
systems. Prof. Lebowitz, a
member of the National Academy of Sciences, is not only a renowned mathematician
and physicist
but also a tireless organizer and editor in statistical mechanics. For
over thirty-five years, his famous
informal Conferences on Statistical mechanics, known as the ``Lebowitz
Meetings", have attracted
top international experts and have been invaluable to young people. He
is the editor-in-chief of the
Journal of Statistical Physics.
Host: Mark S. Alber (Mathematics)
Title: Microscopic Origin of Macroscopic Behavior
Abstract:
Statistical Mechanics provides a framework for describing how well-defined
behavior
may result from the nondirected activity of a multitude of interacting
individual entities. The
subject was developed for, and has had its greatest success so far in,
relating mesoscopic
and macroscopic thermal phenomena to the microscopic world of atoms and
molecules.
Some of the phenomena
are simple additive effects of the actions of individual atoms,
e.g., the pressure exerted by gas in the walls of its container, while
others are paradigms
of emergent behavior, having no direct counterpart in the properties of
dynamics of
individual atoms.Particularly fascinating and important examples of such
emergent
phenomena are phase transitions which would (or should) be astonishing
if they were not
so familiar.
I will give an overview
of recent developments in this field and discuss ways in which one
may adapt the methods of statistical mechanics to higher level collective
systems in which
the relevant basic constituents are themselves more complex than those
for which the
theory was developed.
TOP
Date:
Thursday, November 7, 2002
Time: 4-5 PM
Location: CCE, McKenna Hall Auditorium
Speaker: Prof. Steven
Vogel
James B. Duke Professor of Biology,
Duke University
Host: Glen Niebur (Aerospace & Mechanical Engineering)
Title: The Biomecanics of Ancient Tasks
Abstract:
Through most of our history, muscle has been almost our only engine, whether
our own or
that of a few domesticated animals. So, what we have done and how we have
done
things might just turn on the force and the power of muscle, from clearing
land to moving
stones, propelling boats, and throwing projectiles. The effectiveness
of our devices
depended on how well they could mate that strange engine of our tasks.
The history of
technology has physiological underpinnings.
Date:
Thursday, October 31, 2002
Time: 3:30 PM
Location: 118, Nieuwland Hall, Notre Dame
Speaker: Dr. David
Gidalevitz
University of Leeds
Title: Interaction of Antimicrobial Peptides with Artificial Biomembranes
Abstract:
The emergence of multi-drug resistant strains of bacteria has heightened
resurgent interest
in developing new classes of antibiotics. Over the recent years antimicrobial
peptides with
membrane-lytic activity have emerged as promising therapeutic agents.
One of the hurdles
in development of viable antimicrobial peptides-based drugs is lack of
understanding their
mechanism of action on molecular level. In this talk I will focus on our
very recent efforts
to bridge this gap. Biological membranes were modeled with a planar lipid
monolayer,
whose composition was modified according to a specific type of lipids
present in bacterial
or red blood cell membranes. Interaction of antimicrobial peptides with
cell membranes
is, therefore, represented as interaction between lipid monolayers deposited
on an
aqueous subphase and antimicrobial peptides dissolved in this subphase.
Such model
makes possible use of a variety of powerful and previously inaccessible
to this domain
area experimental techniques such as epifluorescence microscopy, X-ray
reflectivity and
grazing incidence X-ray diffraction.
http://www.leeds.ac.uk/chemeng/staff/Gidalevitz/
Mathematics/Biocomplexity Colloquium
Center for the Study
of Biocomplexity and Department of
mathematics
Date:
April 12, 2002 (Wednesday)
Time: 4:30 pm
Location: Hayes-Healy Hall, 127
Speaker: Hans G.
Othmer
Department of Mathematics, University of Minnesota
Host: Mark S. Alber (Mathematics)
Title: Macroscopic
Equations for Population Dynamics from Microscopic
Models of Individual Behavior
Abstract:
Chemotaxis in the bacterium E. coli is widely-studied because of its accessibility
and
because it incorporates processes that are important in the response of
numerous sensory
systems to stimuli: signal detection and transduction, excitation, adaptation,
and a change
in behavior. Quantitative data on the change in behavior is available
for this system, and
the major biochemical steps in the signal transduction/processing pathway
have been
identified. In this lecture we will discuss a mathematical model of single
cells that can
reproduce many of the major features of signal transduction, adaptation
and aggregation,
and which incorporates the interaction of the chemotactic proteins with
the flagellar
motor. We shall then address the problem of how to obtain macroscopic
chemotaxis
equations for population-level behavior from a forward Kolmogorov equation
that
incorporates certain features of the microscopic model.
Date:
Thursday, February 21, 2002
Time: 4:30 pm
Place: Hayes-Healy Hall, 129
Luc Rey-Bellet
University of Virginia
Host: Mark S. Alber (Mathematics)
Title: Heat conduction and nonequilibrium statistical mechanics
Abstract:
We discuss the properties of non equilibrium steady states of mechanical
systems coupled
to several Hamiltonian reservoirs at positive temperatures: existence,
uniqueness, rate of
convergence, heat flow and its fluctuations.
Last Updated: Friday, November 4, 2005