A jet breaks into droplets that elongate into ellipses...in turn unstable to buckling, as soon as they are thin enough for one wavelength to develop. We end up with these structures that can also be understood through symmetry arguments - see this beautiful work: journals.aps.org/prl/abstract...

When C.reinhardtii cells swim one behind each other, they tend to pull on their neighbors, leading to a pearling instability. In contrast, when they swim side to side, they push on their neighbors, leading to a buckling instability. We control both by steering these phototactic cells with light.

Happy to share that our work on active phase separation by photophobic microalgae is now published in PRL!
journals.aps.org/prl/abstract...

When surrounded by multiple light sources, cells hide behind each other, leading to the quick formation of a macroscopic branching pattern.

And finally, a picture from Irene Joliot-Curie's album (from a small exhibition outside the Curie museum in Paris). She took it in 1939 also in Mont Blanc massif, at the summit of Mt Tondu. In 2023 the Glacier de Tré-la-Tête has hugely receded

..and the Glacier d'Argentiere, that will soon no longer be visible from the village (another old picture displayed at the school)

Here is another view of the Glacier des Bossons that I paired with the current picture.

Another picture displayed in the school shows the Glacier des Bossons as seen from Chamonix a century ago.

The school of physics was founded in 1951 by Cécile DeWitt-Morette, a French physicist then postdoc in the US.

This picture of the Mer de Glace, which is displayed in the school, was taken two years before; since then it has lost ~2,5km in length and 200m in thickness.

Les Houches! Thanks to the organizers and all the participants for a great week of Soft matter & Biophysics in this stunning place