Mathematical Research Seminar - Archive
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Title: Modelling viral evolution in a heterogeneous within-host environment: insights into the HIV co-receptor switch
Abstract: From the point of view of a pathogen, a host is a structured and a heterogeneous environment. In the case of HIV, for example, the existence of spatial structure is supported by the fact that the virus is found in different tissues while environmental heterogeneity originates from the ability of the pathogen to exploit different types of immune cells. To understand how heterogeneity of the within-host environment affects viral evolution we formulate a mathematical model and investigate the conditions under which viral diversification occurs within a host. Applying the model to the case of HIV, we show that the model captures three main properties of the so called co-receptor switch that is observed in many HIV infections: the initial dominance of virus strains that infect CCR5+ cells, the late switch in some (but not all) HIV infections and the associated drop in the number of uninfected T-cells. This suggests that the co-receptor switch may be a result of gradual adaptation of the virus population to target cell heterogeneity. More generally, we argue that mathematical modelling and evolutionary ecology can help us better understand the course of some infections. The talk is based on joint work with Samuel Alizon.
" Finite p-groups: the basics, generators, and automorphisms " (10 lectures) given by Prof. Gustavo A. Fernandez Alcober (University of the Basque Country, Bilbao, Spain).
Program:
1. Basic theory of finite p-groups.
2. Some special families of finite p-groups.
3. Generators of finite p-groups: the Frattini subgroup and the Burnside Basis Theorem.
4. Power-commutator presentations of finite p-groups.
5. Constructing automorphisms: von Dyck's theorem.
6. General structure of the automorphism group of a finite p-group
7. Automorphism groups of some known p-groups
8. Existence of outer automorphisms
9. Open problems about automorphism groups
16.04.2012 Lecturer: Rok Požar (IMFM Ljubljana).
Title: On the split structure of lifted groups
Abstract: Let p: X˜ → X be a regular covering projection of connected graphs, and let CTp denote the group of covering transformations. We present an algorithm for testing whether a given group of automorphisms G˜ ≤ Aut(X˜ ) lifts along p as a split extension of CTp by G in the case when CTp is abelian. Next, we present an algorithm for testing whether G lifts as a split extension such that some complement of CTp within G˜ has an orbit which is a section over a G-invariant set of vertices of X . Both algorithms are part of a larger package (implemented in MAGMA) for doing computations with graph covers. The implementation allows computing with graphs having semiedges.
Slides from the talk are available here: DOWNLOAD!
02.04.2012 Lecturer: dr. Martin Mačaj (Comenius University, Slovakia and UP FAMNIT).
Title: Nonorientable regular maps over linear fractional groups
Ob 25. obletnici Erasmusa je slovenska nacionalna agencija CMEPIUS pripravila natečaj »Erasmus in jaz«. Nagradili bodo najboljši video posnetek, fotografijo ali zgodbo z delovnim naslovom »Izkušnja z Erasmus mobilnosti kot priložnosti za osebni in strokovni razvoj študenta«. Razglasitev rezultatov in podelitev dobrih nagrad bo potekala 7. maja v Mariboru v okviru promocijske kampanje Mladi in mobilnost.
Danes, 02. april 2012, je zadnji dan za oddajo gradiva!!!
Več o natečaju izveste na spodnji povezavi http://www.cmepius.si/vzu/erasmus/natecaj-2012.aspx.
