5
Aprile
ore 12.0014.00
Aula Consiglio 
Anton Bovier
Stochastic individual based models: from scaling limits to modelling of cancer therapies
Stochastic individual base models, that is,
measure valued Markov processes describing the evolution of interacting biological populations,
have proven over the last years to be effective models in deriving key features of the theory of
adaptive dynamics, such as the canonical equation of adaptive dynamics, the trait substitution
sequence and the polymorphic evolution sequence. In this talk I review these models an the diverse
emerging scaling limits, and I report on recent progress in applying such models to the modelling of
cancer therapies, and in particular to immunotherapy and combination
therapies of melanoma, based on experimental data by colleagues from the Bonn university hospital.

8
Marzo
ore 12.0014.00
Aula Consiglio 
Antonio De Simone
Flagellar swimming and amoeboid motion in Euglena
gracilis: the how and why of a behavioral change in a unicellular
organism
Euglena gracilis is a
unicellular protist exhibiting different motility strategies: swimming
by flagellar propulsion, or crawling thanks to large amplitude shape
changes of the whole body (a behavior known as amoeboid motion, or
metaboly).
Swimming is propelled by the nonplanar beating of a composite
flagellum powered by an axoneme, with molecular motors sliding over
microtubule bundles (arranged according to the “standard” 9+2
architecture).
The nonplanar
beating of the flagellum leads in turn to helical
trajectories coupled with body rotations, and these rotations play an
important role in the phototactic behavior of E. gracilis.
Confinement triggers a behavioral change, namely, E. gracilis switches
from flagellar swimming to ameboid motion, which is propelled by
peristaltic waves along the body of the organism. These are powered by
molecular motors driving the relative sliding of pellicle strips lying
underneath the plasma membrane. The mechanisms controlling the gait
switch in this unicellular organism are still unknown.
Our most recent findings on the motility of E. gracilis, which are the
result of a combined theoretical and experimental analysis, will be
surveyed.
Image: flagellar shapes and resulting trajectories
of the cell body (green) and eyespot (red) of Euglena gracilis

22
Febbraio
ore 12.0014.00
Aula Consiglio 
Karl Sigmund
Social learning leads to the recurrence of
corruption
Cooperation can be
sustained by institutions that punish freeriders. Such institutions,
however, tend to be subverted by corruption if they are not closely
watched. Monitoring can uphold a regime of honesty and cooperation, but
usually comes at a price. The temptation to skip monitoring regularly
leads to outbreaks of corruption and the breakdown of cooperation. We
model the corresponding cycle by means of evolutionary game theory,
using analytical methods and numerical simulations. The results confirm
the view that transparency is a major factor in fighting corruption.

18
Gennaio
ore 12.0014.00
Aula Consiglio 
Andrea
Puglisi
Granular Brownian Motion
Granular materials are
made of macroscopic particles, called grains: sand, rice, sugar and
powders are typical examples. They are important in our everyday life,
in many industrial applications and in the prevention of geophysical
hazards. In physics,
mainly in the realm of nonequilibrium statistical mechanics, granular
systems are an inspiring source of phenomena and questions. The
simplest model of granular material is a "fluid" made of inelastic hard
spheres. For such a system  in the dilute limit  the classical
program of kinetic theory (Boltzmann equation, ChapmanEnskogbased
hydrodynamics, and much more) has been developed by physicists and
mathematicians in the last decades. In this seminar, after recalling a
few key results of such a theoretical activity, I will focus on a
series of experiments made in my laboratory in the last 5 years. They
concern the statistical properties of a massive probe immersed in a
steady state granular fluid. The fluid is obtained by
vibrofluidization of a large number of hard spheres of different
materials, while the probe is a rigid rotator whose angular
displacement and angular velocity are the key observables. In the
dilute limit one conjectures a Markovian approximation for the
rotator's dynamics which explains many aspects of the experiment,
including a qualitative understanding of "motor effects" in the
presence of rotator's asymmetries. Further noticeable facts appear when
the granular fluid is not dilute, mainly the violation of the
mobilitydiffusivity Einstein relation, and anomalous diffusion. For
these phenomena a predictive theory is lacking and only
phenomenological models are available.

