[Fun] Japonais

Pas si fous ces japonais! Une serie de videos pour un programme televise Japonais pour eduquer les enfants, "PitagoraSuicchi". D'apres wikipedia, ce type de machines fut introduit par "Rube Goldberg, un dessinateur de "cartoons", les petites bandes dessinnees dans les journaux. Le programme televise est surtout un spectacle de marionnettes, mais il en profite pour introduire des concepts scientifiques, ponctue par ces petites videos Autre chose que les japoniaiseries de Club Dorothee de mon enfance :) Si ces machines vous rappellent quelque chose, c'est peut-etre une reminiscence de "Retour vers le futur", numeros 1 et 3, ou Emmet Brown fait son cafe ou de la glace avec une machine horriblement complique. Ou alors, les machines de Coyotte pour attrapper son "beep-beep". Moi, ca me rappelle indirectement la Machine de Turing a Vapeur de l'universite de Washington :)

[Fun] Risk Party

Kawai!!!!!
Originally uploaded by LeJyBy.

Apres un week-end passe principalement a dormir et a faire le menage, avant et apres mes 10 km en monocycle pour la "Terry Fox Run", j'ai fini mon dimanche par une gentille soiree "Risk" avec un nouveau groupe d'amis, dont une charmante Serbe que vous pouvez admirer ci-joint [Edit: J'ai aussi trouve une italienne!]. Ca fait du bien de socialiser en dehors des cercles habituels, de ne pas parler boulot, d'etre insouciant, d'etre integre aussi vite dans un nouveau groupe (j'ai joue au foot une fois avec eux, et soudain je suis invite personellement a toutes les soirees...). Ca me rappelle Paris! :)

J'ai aussi un nouveu jouet pour m'amuser, un clavier musical usb de trois octaves. En conjonction avec GarageBand, sous Mac OS, c'est un merveilleux instrument. Je joue un accompagnement (tres basic) au piano, le met a jouer en loupe, puis joue de l'armonica, du concertino et de la clarinette (je n'ai pas encore ose m'enregistrer au trombone, meme si j'ai fait des progres) par dessus. Et comme chaque instrument est enregistre separement, je peux adapter le volume de chacun, couper les parties que je n'aime pas, le pied total! Il ne me manque que le temps pour enregistrer un autre CD ;)

[Science] Quasicrystals

I saw an awesome talk yesterday, part of the series organized by the Perimeter Institute. Paul Steinhardt is a famous physicist from Princeton. He described the history of the research on "quasicrystals", how it went from the status of an impossibility, then to the status of a theoretical possibility, to finally reach the status of a admitted fact, with at each step some people (physicists) claiming that the next step was impossible. I appreciate to its right value the remark from Paul when I chatted with him after the talk: "it just proves that you should not trust results unless they are formally proved". Allelouia! Finally a physicist saw the light!!! ;) [Edit 2006/09/18: Although by saying so, he once again claim a "proof" which isn't one, merely an example...]

His talk was very good, reaching scientists as well as children, with several sessions with a webcam pointed from above to a brightly lighted table, allowing him to do live demonstrations. I heard about it but that's the first I saw. I would like to have one in class, and it would certainly be a must for video conferences. Does not seem expensive, we should see them arrive soon at the university. He also exhibited a 3d construction obtained through a "3d printer", which you can see on the picture on the side, hold by another Paul. I heard about those 3d printers, but again that was the first time I saw for real an objected thus created. I guess we will wait long before we get those at the University though...

One thing excited me a lot. The quasicrystals are based on a relaxation of the definition of a crystal, which permit materials with similar or stronger properties than crystals. The main arguments against their real existence, as opposed to a theoretical object, was that to create them one would need non-local rules. This was ultimately solved by finding a set of local rules allowing to create quasicrystals. You can see an example of how those local rules are implemented in the real world on the pictures on the right: the notches identify the faces and forbid some alignments, forbidding local moves which could result in a contradiction in the global construction.

I had the same problem with the Bak Sneppen model, a model of evolution on which I worked for quite a while: we have a model with nice properties, which could explain many things in Nature, but it uses non local rules, so that detractors claim that this model can't be true. I asked Paul Steinhardt if he knew some mathematical analysis of quasicrystals, so that I could try to apply their analysis in space time rather than in the 3 geometric dimension, but he claims that mathematicians refuse to work on those. He made me wanting to look more at this problem, I will do some more bibliography! [Edit 2006/09/18: Of course, there is a large bibliography in Mathematics about such processes, and that actually I knew some of it...] The video of the talk should soon be uploaded on the mediasite of the Perimeter Institute, and you can read the abstract of the talk.