Applied Math Seminar

James D. Englehardt, Ph.D., P.E.
Professor, Environmental Engineering
University of Miami

will present

Why Does North America Have the Highest Cancer Rate in the World?
A Suggested Alternative to the Central Limit Theorem in Nonlinear Correlated Systems and Networks and Its Use in Dose-response Assessment

Friday, April 25, 2008, 4:30pm
Ungar Room 402


Abstract: The magnitudes of hurricanes, solar flares, citation rates, web connections, illness severities, and many other complex system outcomes are observed to have asymptotic power law distributions. However, power laws typically require truncation or empirical cutoff, often requiring additional parameters. The Weibull form on the other hand has been shown to model a broad range of complex system outcome sizes directly. Weibull-form distributions, continuous and proposed discrete, will be shown in this talk to be stable, attracting distributions of outcome size in multiplicative, correlated systems. Multiplicative systems are considered zeroth order models of many complex systems, and system outcome causes are typically inter-related and correlated. And while power laws are also multiplicatively stable in correlated systems, the Weibull emerges naturally from finite-mean, exponentially-distributed cause sizes. Also, in well-correlated systems even sums tend towards the parent distribution. Thus, the Weibull form may have generality in nonlinear correlated systems analogous to that of the Gaussian in linear independent systems. Accordingly, the Weibull is suggested with simple models to simulate nonlinear system outcomes such as simulated illness severities. A corresponding emergent multivariate dose-response function for chemical mixtures is then derived, accounting for covariance structure. The result is validated versus data on chloroform-induced liver necrosis in mice, and toluene/benzene-induced embryo mortality in Japanese medaka. Further empirical verification is suggested, with the goal of timely predictive Bayesian dose-response assessments based on available and possibly conflicting information, to shed light on chemical drivers of cancer and other disease.

---

Combinatorics Seminar

Professor Eric Gottlieb
Rhodes College

will present

Fair Division, Voting Theory, and Posets

Thursday, March 6, 2008, 2:00pm
Ungar Room 411


Abstract: We describe a way to use posets to bring techniques from voting theory to bear on the problem of fairly distributing indivisible items. One of the posets that plays an important role is isomorphic to the quotient of a Coxeter group by a maximal parabolic subgroup. We will also mention a number of practical obstacles to the implementation of this program.

---

Geometry and Physics Seminar

Professor N. Saveliev
University of Miami

will present

Asymptotics for End-periodic Dirac Operators

Wednesday, March 5, 2008, 4:00pm
Ungar Room 411

---

Geometry and Physics Seminar

Y. Soibelman
KSU

will present

Quantizing K3 Surfaces

Wednesday, January 30, 2008, 4:00pm
Ungar Room 411

---

Geometry and Physics Seminar

A. Kuznetsov
RAS

will present

Categorical Resolutions of Singularities

Monday, January 28, 2008, 4:00pm
Ungar Room 411


Abstract: I will give a definition of a categorical resolution of singularities and explain how such resolutions can be constructed.

---

Applied Math Seminar

Lev Kapitanski
University of Miami

will present

Dynamics with Choice

Friday, November 16, 2007, 4:30pm
Ungar Room 402


Abstract: Dynamics with choice is a generalization of discrete-time dynamics where instead of the same evolution operator at every time step there is a choice of operators to transform the current state of the system. This notion is new interesting from the mathematical point of view. At the same time, many real life processes studied in chemical physics, engineering, biology and medicine, from autocatalytic reaction systems to switched systems to cellular biochemical processes to malaria transmission in urban environments, exhibit the properties described by dynamics with choice. Based on our recent work with Sanja Zivanovic, I will describe preliminary results concerning the long-term behavior in the dynamics with choice.

---

Geometry and Physics Seminar

Professor B. de Oliveira
University of Miami

will present

Symmetric Differentials and the Geometry and Topology of Projective Manifolds

Wednesday, October 10, 2007, 4:00pm
Ungar Room 402

---

Geometry and Physics Seminar

Professor S. Kaliman
University of Miami

will present

Algebraic Volume Density Property of Affine Algebraic Varieties

Wednesday, October 3, 2007, 4:00pm
Ungar Room 402


Abstract: Recall that the algebraic density property of affine algebraic manifold means that the Lie algebra generated globally integrable algebraic vector fields coincides with the space of all algebraic vector fields. We discuss recent developments in the study of this property and more complicated algebraic volume density property which means the similar equality for the Lie algebra and the space of vector fields with additional requirement that their divergence with respect to a given volume form is zero.

---

Applied Math Seminar

Professor Suzanne Lenhart
University of Tennessee

will present

Rabies in Raccoons:
Optimal Control for a Discrete Time Model on a Spatial Grid

Friday, September 14, 2007, 4:30pm
Ungar Room 402


Abstract: An epidemic model for rabies in raccoons is formulated with discrete time and spatial features. The goal is to analyze the strategies for optimal distribution of vaccine baits to minimize the spread of the disease and the cost of implementing the control. Discrete optimal control techniques are used to derive the optimality system, which is then solved numerically to illustrate various scenarios.

---

Geometry and Physics Seminar

L. Katzarkov
University of Miami

will present

A Different Look at the Hodge Conjecture

Wednesday, September 12, 2007, 4:00pm
Ungar Room 402

---

Geometry and Physics Seminar

Leonid Parnovski
University College London

will present

Bethe-Sommerfeld Conjecture for Periodic Pseudo-differential Operators

Wednesday, September 5, 2007, 4:00pm
Ungar Room 402

---

Geometry and Physics Seminar

Dr. Alexander Silbergleit
GP-B W.W.Hansen Experimental Physics Laboratory
Stanford University

will present

Gravity Probe B Relativity Science Mission:
Instrument, Flight, Data Analysis, and the First Glimpses of the Result

Wednesday, April 18, 2007, 4:30pm
Physics Conference Room

---

Geometry and Physics Seminar

Professor A. Akhmedov
Georgia Institute of Technology

will present

Small Exotic 4-Manifolds

Monday, April 9, 2007, 4:00pm
Ungar Room 506


Abstract: In this talk, we will present the new examples of symplectic manifolds with same integral cohomology as S^2 x S^2. We also discuss the generalization of these examples as well as its application in the construction of simply connected 4-manifolds with small Euler characteristic.