Buongiorno inoltro l'annuncio per il OWPS di domani, che sarà relazionato alla biologia. Saluti Alessandra
---------- Forwarded message --------- Da: One World Probability ow.probability@gmail.com Date: mer 10 mar 2021 alle ore 09:32 Subject: [owps] One World Probability Seminar Thursday March 11, 2021 To: owps@lists.bath.ac.uk
Tomorrow's speakers in the One World Probability Seminar are (Note: all times are in UTC. *Due to time changes, you should check what that translates to in your location*) ------------------------------------------------
(14:00-15:00 UTC) Speaker: Viet Chi Tran (Université Gustave Eiffel) Title: Limit Theorems for Historical Particle Systems Abstract: To describe the evolving phylogenies of a birth and death process with trait structure and ecological interactions, we build a historical process inspired by works by Dawson and Perkins (1991 and 1995): it is a càdlàg process whose value at time t is a measure on lineages stopped at this time, i.e. paths describing the trait ancestries of the individuals living at time t. The dynamics may depend on past traits and allows interactions between individuals through their lineages. We establish the convergence of the individual-based birth-death process to a nonlinear historical superprocess, under the assumptions of large populations, small individuals and allometric demographies. The limit is described here by a macroscopic martingale problem. Because of the interactions, the branching property fails and we use fine couplings between our population and independent branching particles. This is a joint work with Sylvie Méléard.
(15:00-16:00 UTC) Speaker: Sylvie Méléard (École Polytechnique, Paris) Title: Historical Processes and Dynamics of Phylogenies in a Population with Climate Change Abstract: We investigate in a simple model how the phylogenies of living individuals are shaped by the adaptation to a varying environment. In this model, the individuals are characterised by one-dimensional real traits (or positions). The stochastic individual-based birth-death process depends on a time-changing growth rate that shifts the optimal trait to the right and depends on a nonlinear logistic competition term. The macroscopic behaviour is described by a PDE that admits a unique positive stationary solution. We are interested here in the ancestral lineages of the living individuals in the stationary regime. The dynamic of these lineages is modelled by a historical process, approximatively close to a similar one with non-linearity frozen to its stationary value. We then use a many-to-one identity together with Feynman-Kac's formula and fine stochastic calculus to completely describe the limiting distribution, in large populations, of the path of an individual drawn at random at a given time. This path, in reversed time, is approximated by a simple Ornstein-Uhlenbeck. It shows how the lagged bulk of the present population stems from ancestors once optimal in trait but still in the tail of the trait distribution in which they lived. This talk is based on a joint work with Vincent Calvez, Benoit Henry and Viet Chi Tran. ------------------------------------------------
The zoom link will appear the day before on the OWPS website: https://www.owprobability.org/one-world-probability-seminar https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.owprobability.org%2Fone-world-probability-seminar&data=04%7C01%7Cowps%40lists.bath.ac.uk%7C043912ddefd34c12a1c008d8e39ef0ae%7C377e3d224ea1422db0ad8fcc89406b9e%7C0%7C0%7C637509619066442081%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=dpNKsBeZWxjA1wRqPg5b7GnEmR4mAwzdob3%2FOo9RTyg%3D&reserved=0
It can also be directly accessed through the link below: https://uniroma1.zoom.us/j/86028841260?pwd=bUxyVUYzSjY5dDR4d3krb2lDTHZDQT09 https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Funiroma1.zoom.us%2Fj%2F86028841260%3Fpwd%3DbUxyVUYzSjY5dDR4d3krb2lDTHZDQT09&data=04%7C01%7Cowps%40lists.bath.ac.uk%7C043912ddefd34c12a1c008d8e39ef0ae%7C377e3d224ea1422db0ad8fcc89406b9e%7C0%7C0%7C637509619066452036%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=cQfHHjy6ddUxMwSSqj3JyjYtChFm1kRUA3lVNQCdUrk%3D&reserved=0 Meeting-ID: 860 2884 1260 Passcode: 868252
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We hope to see you all tomorrow! One World Probability Team