A propos du centre ou de la direction fonctionnelle

The Inria research centre in Lyon is the 9th Inria research centre, formally created in January 2022. It brings together approximately 300 people in 17 research teams and research support services.

Its staff are distributed in Villeurbanne, Lyon Gerland, and Saint-Etienne.

The Lyon centre is active in the fields of software, distributed and high-performance computing, embedded systems, quantum computing and privacy in the digital world, but also in digital health and computational biology.

Contexte et atouts du poste

Scientific context:

Slime molds (Physarum polycephalum) are unicellular organisms that display two levels of fractality. First, their intracellular cytoskeleton forms a complex cytoplasmic fractal network of "veins". The vein network allows the transport of respiratory gases, molecules and organelles within a cell ranging from 500 μm² to 10 m². The vein network shows properties of almost self-similarity and complex patterns that emerge from simple rules, which are hallmarks of fractal geometry. This network adapts continuously in response to environmental conditions, optimizing the transport for resource delivery and resilience. In addition, the slime mold plasma membrane presents an irregular appearance with numerous invaginations at multiple scales. The membrane invaginations are involved in the uptake of nutrients, transport of water and ions, extrusion of molecules, secretion of slime. This membrane is a dynamic structure, constantly changing as the organism moves, feeds, and explores its environment. Like the vein network, the membrane can display complex, adaptive behavior that can fold and unfold at various length scales, thus also exhibiting a fractal-like organization.

The aim of the project is to model the multiscale functioning and growth of slime molds using fractal geometry.

This works takes place in the ANR project Fractals (2025-2028).

Partners:

• Claire David, Sorbonne Université, Paris
• Christophe Godin, Inria-ENS de Lyon, Lyon
• Audrey Dussutour, CNRS & University Paul Sabatier, Toulouse
• Michel Lapidus, University of California, USA

Mission confiée

Post-doc project:

A 2-years post-doc position is open in the project to model the functioning and growth of the slime mold. On the one hand, graphs describing the fractal vein network in space and time of the slime mold will be available (based on previous work of the partners that relies on segmentation of 2D images of the slime mold structure and dynamics). On the other new concepts and tools from fractal theory will be used and further developed in the project to model the transport of substances in such fractal structures. The goal of the work will be to adapt the new mathematical fractal theory to the modeling of substance transport through these fractal networks using an adapted form of differential equations on fractals, solve these equations and study the properties of such dynamical models. A 2D computational model of the slime mold growth will be implemented as a proof on concept to map the theoretical development of the model onto quantitative observations and test responses of the model to various types of changes in the growth conditions (e.g. temperature, nutrients, etc.).

Principales activités

Main activities :

• Conceive a mathematical model of the slime mold growth, including transport and geometrical processes, based on fractal and differential formalisms
• Develop a computational implementation of this model to carry out growth simulations and test biological/physical hypotheses
• Analyze the results and compare them with biological data obtained by our partners
• Publish the results in international journals/conferences

Avantages

• Subsidized meals
• Partial reimbursement of public transport costs
• Leave: 7 weeks of annual leave + 10 extra days off due to RTT (statutory reduction in working hours) + possibility of exceptional leave (sick children, moving home, etc.)
• Possibility of teleworking (90 days / year) and flexible organization of working hours Social, cultural and sports events and activities
• Access to vocational training
• Social security coverage under conditions

Rémunération

2788 € gross salary / month