QLS - 2 Guest Seminars - 8 and 9 January 2018

[Quantitative Life Sciences]

The QLS section will host two guest seminars:

- Monday 8 January at  11:30 - ICTP, Central Area, 2nd floor, SISSA 
building, Via Beirut

Title: "Disentangling bacterial invasiveness from lethality in an 
experimental host-pathogen system "

Speaker: Tommaso Biancalani - Massachusetts Institute of Technology


Abstract:
Understanding virulence remains a central problem in human health, pest 
control, disease ecology and evolutionary biology. Bacterial virulence 
is typically quantified by phenomenological indicators such as the 
/LT50/ (i.e. the time taken to kill 50% of an infected population). 
However, virulence emerges as a result of complex processes that occur 
at different stages: the pathogen needs to breach the primary host 
defenses, find a suitable environment to replicate, and finally express 
the virulence factors that cause lethality. It is well-known that 
pathogens exhibit a very broad spectrum of strategies to accomplish 
these three tasks, yet, phenomenological indicators such as the /LT50/ 
cannot distinguish the ability of the pathogen to invade the host from 
its ability to kill the host. Here, we propose a physical host-pathogen 
theory that shows how to disentangle colonization, growth, and pathogen 
lethality from the survival kinetics of a host population. Experimental 
data from /Caenorhabditis elegans/ nematodes exposed to various human 
pathogens shows that host mortality becomes severe only once the 
pathogen population has reached its carrying capacity within the host. 
In the talk, I will present our theory and compare predictions against 
experimental data.

Indico web page: http://indico.ictp.it/event/8470/

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- Tuesday 9 January at 12:00 - ICTP, Central Area, 2nd floor, SISSA 
building, Via Beirut

Title: "Records of Entropy Production at the Nanoscale"

Speaker: Edgar Roldan, Max Planck Institute for the Physics of Complex 
Systems, Dresden, Germany

Abstract:
The laws of thermodynamics can be extended to the nanoscale, where 
fluxes are fluctuating quantities. Little is known about extreme-value 
statistics of thermodynamic fluxes characterising the most extreme 
deviations from the average behaviours. Using Martingale theory, we 
study statistics of the negative records of stochastic entropy 
production in nonequilibrium steady states, and derive universal 
inequalities for such distributions of records. Furthermore, we explore 
the implications of our results in two non-equilibrium nanoscopic 
systems: single-electron transistors and molecular motors. We report on 
the experimental measurement of stochastic entropy production and of 
records of negative entropy in a metallic double dot under a constant 
external DC bias. Experimental results on the double dot confirm our 
theory and reveal a novel bound for the maximal heat that a mesoscopic 
system can absorb from its environment. We also explore our results in 
active biological processes and find predictions for the maximal 
excursion of a molecular motor against the direction of an external force.

Indico web page: http://indico.ictp.it/event/8473/


Everyone interested is most welcome to attend!

-- 
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