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domingo, abril 20, 2008

Ubiquity


Como vocês sabem, este não é um blog jornalístico de divulgação científica, mas um "weblog" de viagem na vida científica. Isso quer dizer que vou registrando aqui notícias e referências que vou encontrando nas minhas navegações, idéias para papers, idéias "malucas" que um dia talvez poderiam se mostrar frutíferas, divulgação dos meus trabalhos e dos meus amigos, comentários diversos "sem ciência" e principalmente tudo o que acho que vou esquecer se não anotar. Ah, sim, tem uma dose exagerada de "auto-centrismo" (eufemisticamente falando), mas o blogueiro que não tiver ego que atire a primeira pedra...

Bom, hoje, de novo, vou divulgar um livro que recomendo aos meus alunos. Abaixo, meu review na Amazon, escrito sob o pseudônimo literário de B. B. Jenitez:

This is the book that I would like to have written. Although being a popular account, it is scientifically accurate and carefull in its suggestions, always informing the reader what is consolidated science and what is scientific speculation. In contrast to a previous review, I have read all the pages of this book. Since I am a physicist working in this very subject (self-organized criticality), I probably can say that if someone use the example of a Gaussian (bell shaped curve) to illustrate that the power laws discussed in the book are trivial, well, this person have not understood anything. Gaussians have exponential decays, so they predict that very larg events (catastrophes) will occur with vanishing probability. For example, the heigh of people is distributed as a Gaussian. What is the probability of finding a 3 meter person? Zero.

Distributions wich have power law tails, depending on the power exponent, may have no well defined variance or even average value. This means that there is no "average" earthquake, and that very big earthquakes (or other cathastrophes) are not "acts of God" but have a no desprezible chance of occur due to simple chain reactions of events.
I have introduced my students to ideas like critical states and modern physical thinking by using this book. So, I can recommend it to any reader without reserve. The emphasis by the author that critical chain reactions of events must be accounted by any view of History and Society is an important mind tool in our increasing interconnected (and, because it, prone to global chain reactions) world.

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