TODAY! "Physics of complex systems: Fast forward" seminars - 21 February

[Quantitative Life Sciences]

Dear All,

On Wednesday, 21 February, the Session "Physics of complex systems: Fast 
forward" of the Spring College on the Physics of Complex Systems 
<https://indico.ictp.it/event/10459/overview> 
https://indico.ictp.it/event/10459/other-view?view=ictptimetable will 
feature two seminars:

_14:00 - 15:00 - Modelling computations in brain circuits with low-rank 
neural networks - Francesca MASTROGIUSEPPE __(Champalimaud Research, 
Portugal)_

Abstract:
Our brain consists of billions of neurons, arranged in a multitude of 
areas and densely interconnected through trillions of synapses. How do 
interactions within this large complex network support the computations 
that are required by our everyday behaviour? Current experimental 
technologies enable the investigation of this question in animal models 
on a large scale. However, due to the heterogeneity and complexity of 
the resulting data, building mechanistic models of computations in 
neural circuits that are together interpretable, flexible, and 
data-grounded remains challenging.

In this presentation, I will introduce a new class of mathematical 
models, named low-rank neural networks, aiming to address these 
challenges. These models are rooted in the idea of integrating concepts 
and tools from dimensionality reduction, a statistical approach that has 
demonstrated promise in the analysis of experimental data, into neural 
network models. The key strength of low-rank networks is that they can 
be easily analysed mathematically, by using tools from statistical 
physics and random matrix theory. I will show how this formalism can be 
used to address standing theoretical questions in neuroscience and 
artificial neural networks. I will also briefly discuss how those models 
can be used to extract insight from large-scale experimental data, with 
a focus on neural data collected from multiple cortical areas in the 
brain of non-human primates.

_
15:30 - 16:30 - Self-organization of bacterial ecosystems from micro to 
macro -  Alberto DINELLI (Université Paris Cité, Laboratoire Matière et 
Systèmes Complexes-MSC, France)_

Abstract:
 From bacterial suspensions to bird flocks, the living world is 
permeated with agents that are able to exert non-conservative forces on 
their surroundings, and, as such, behave as active particles. Due to 
their intrinsically out-of-equilibrium nature, these systems exhibit a 
rich variety of emergent phenomena, such as collective motion, phase 
separation in the absence of attractive forces, run-and-chase dynamics, 
and much more.

In this talk, I will discuss how motility regulation in bacterial 
systems shapes the collective organization of the community. In 
particular, I will consider quorum-sensing interactions, through which 
bacteria adapt their motility based on the local density of their peers. 
Starting from the microscopic dynamics of interacting bacteria, I will 
show how one can derive the large-scale hydrodynamics of the system, 
which in turns allows to predict and characterize the emerging 
phenomenology.

I will show how this framework can be applied to account for the 
self-organization of bacterial ecosystems, where multiple species of 
bacteria live and interact in the same environment. By explicitly 
bridging microscopic and macroscopic dynamics, I will show that, under 
conditions that are derived explicitly, the system is effectively 
described by a large-scale equilibrium theory. In turn, this will allow 
us to account quantitatively, and without fitting parameters, for the 
rich behaviors observed in microscopic simulations including phase 
separation, demixing, and multi-phase coexistence. Finally, when the 
effective-equilibrium condition is violated, I will show the emergence 
of a wealth of dynamical patterns, corresponding to a run-and-chase 
dynamics between different bacterial strains.

_Venue: Kastler Lecture Hall, Adriatico Guest House, Riva Massimiliano e 
Carlotta, Grignano I - 34151 Trieste (Italy)_


Best regards,
Erica

-- 
Erica Sarnataro
Group Secretary
Quantitative Life Sciences
The Abdus Salam International Centre for Theoretical Physics (ICTP)
Trieste,  Italy
Tel. +39-040-2240623
www.ictp.it/research/qls.aspx
e-mail:qls at ictp.it