news 2020

Seasonal fluctuations drive the dynamics of many infectious diseases. For instance, the flu spreads more readily in winter. Two scientists from the University of Nantes 1 and the CNRS 2 in Montpellier have developed a mathematical model to predict the risk of the emergence of an epidemic, depending on the time of the year at which the pathogen is introduced.

What makes ships mysteriously slow down or even stop as they travel, even though their engines are working properly? This was first observed in 1893 and was described experimentally in 1904 without all the secrets of this "dead water" being understood. An interdisciplinary team from the CNRS and the University of Poitiers has explained this phenomenon for the first time: the speed changes in ships trapped in dead water are due to waves that act like an undulating conveyor belt on which the boats move back and forth.

Usain Bolt's 200m record has not been beaten for ten years and Florence Griffith Joyner's for more than thirty years. And what about if the secret behind beating records was to use mathematics' Thanks to a mathematical model, Amandine Aftalion, CNRS researcher at the Centre d'analyse et de mathématique sociales (CNRS/EHESS), and Emmanuel Trélat, a Sorbonne Université researcher at the Laboratoire Jacques-Louis Lions (CNRS/Sorbonne Université/ Université de Paris) have proved that the geometry of athletic tracks could be optimised to improve records.