Seminars and Colloquiums
for the week of March 2, 2009
Speakers:
Ms. Carrie Eaton, Monday
Associate Professor Nikolay Brodskiy, Tuesday
Mr. Alvaro Martinez-Perez, Universidad Complutense de Madrid, Tuesday
Dr. Seyed Moghadas, Institute for Biodiagnostics, National Research
Council, Canada, Wednesday
Assistant Professor Remus Nicoara, Wednesday
Professor Francisco Ruiz del Portal, Universidad Complutense de Madrid, Wednesday
Mr. Kirill Yakovlev, Thursday
Mr. Jose Higes, Universidad Complutense de Madrid, Thursday
Monday, March 2
MATH ECOLOGY SEMINAR
TIME: 11:20 – 12:10 p.m.
ROOM: Dabney 575
SPEAKER: Ms. Carrie Eaton
TITLE: “Ecological Networks”
Tuesday, March 3
WORKSHOP ON COURSE GEOMETRY
TIME: 2:30 – 3:20 p.m.
ROOM: AC 113A
SPEAKER: Associate Professor Nikolay Brodskiy
TITLE: "Amenability III "
TOPOLOGY SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113A
SPEAKER: Mr. Alvaro Martinez-Perez, Universidad Complutense de Madrid
TITLE: “Quasi-isometries between visual hyperbolic spaces”
ABSTRACT: We prove that a PQ-symmetric homeomorphism between two complete metric spaces can be extended to a quasi-isometry between their hyperbolic approximations.
This result is used to prove that two visual Gromov hyperbolic spaces are quasi-isometric if and only if there is a PQ-symmetric homeomorphism between their boundaries.
Wednesday, March 4
COLLOQUIUM – NIMBioS Job Candidate
TIME: 3:30 – 5:00 p.m.
ROOM: A-118 VTH (Voss Veterinary Teaching Hospital)
SPEAKER: Seyed Moghadas, Institute for Biodiagnostics, National Research
Council, Canada
TITLE: “Dynamics of resistance emergence in influenza infection with
compensatory mutations”
ABSTRACT: Evolutionary responses of influenza viruses invoke strategies
to escape the pressures that limit their replication and spread. Compensatory mutations are among well-known responses that can result in the generation of escape mutants from immune recognition or emergence of highly transmissible drug resistant viruses. In this talk, by developing a mathematical model, I will investigate the role of these mutations in the evolution of resistance in the context of viral-immune dynamics. Model simulations, using parameter estimates reported in the published literature, suggest that resistance is unlikely to emerge without compensation for the large fitness cost associated with the initial rise of resistant mutants. The results show that, in the absence of virus-specific immune memory, the time for start of treatment and the efficacy of drugs in suppressing viral replication are critical measures in the invasion of compensated mutants. However, pre-existing immune responses can irresistibly impede viral replication and prevent the
outgrowth of resistance, regardless of treatment regimens. While uncertainties of parameter values pertaining to the in vivo dynamics remain to be addressed, the findings suggest that the presence of immune memory may be a key factor in preventing lethal consequences of infection.
ANALYSIS SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113A
SPEAKER: Assistant Professor Remus Nicoara
TITLE: “Continuous deformations of commuting squares and subfactors, II”
ABSTRACT: In the early 80's V. Jones introduced the theory of subfactors, as a Galois theory for inclusions of von Neumann algebras. A subfactor can be viewed as a group-like object that encodes the symmetries of a quantum physical or mathematical situation. In this second talk I will discuss subfactor invariants and introduce the notion of commuting squares, squares of *-algebras which arise as invariants and construction data for subfactors.
TOPOLOGY SEMINAR
TIME: 3:35 – 4:25 p.m.
ROOM: AC 113
SPEAKER: Professor Francisco Ruiz del Portal, Universidad Complutense de Madrid
TITLE: “Indices of the iterates of R3-homeomorphisms at fixed points which are isolated invariant sets (joint work with P, Le Calvez and J.M. Salazar)”
ABSTRACT: Let \(U \subset {\mathbb R}3\) be an open set and \(f:U \rightarrow f(U) \subset {\mathbb R}3\) be a homeomorphism. Let \(p \in U\) be a fixed point. It is known that, if \(\{p\}\) is not an isolated invariant set, the sequence of the fixed point
indices of the iterates of \(f\) at \(p\), \((i(f^n,p))_{n\geq 1}\), is, in general, unbounded.
In this talk we will show that when \(\{p\}\) is an isolated invariant set, the sequence \((i(f^n,p))_{n\geq 1}\) is periodic. Conversely, for any periodic sequence of integers \((I_n)_{n \geq1}\) satisfying Dold's necessary congruences, there exists an
orientation preserving homeomorphism such that \(i(f^n,p)=I_n\) for every \(n\geq 1\).
Finally if I have time we will also present an application to the study of the local structure of the stable/unstable sets at \(p\).
Thursday, March 5
PROBABILITY SEMINAR
TIME: 12:40- 1:55 p.m.
ROOM: HBB 132
SPEAKER: Mr. Kirill Yakovlev
TITLE: "Two-step variation for processes driven by fractional Brownian motion with applications in testing for jumps in the high frequency data. Part 3”
TOPOLOGY SEMINAR
TIME: 2:30 - 3:20 p.m.
ROOM: AC 113A
SPEAKER: Mr. Jose Higes, Universidad Complutense de Madrid
TITLE: “Coarse embeddings into abelian groups”
ABSTRACT: We study the problem of detecting countable groups that are (bijectively) coarsely equivalent to countable abelian groups. Such class of groups contains abelian-by-finite groups and locally finite-by-abelian groups.
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.
Week of:
Past notices:
Seminars from 2007-2008 academic year
Seminars from 2006-2007 academic year