Archive for August 30th, 2006

Symmetry breaking!

August 30, 2006

Symmetry breaking transitions in equilibrium shapes of coherent precipitates is the first PhD thesis to come out of the computational materials science lab at IISc Bangalore. Spontaneous symmetry breaking is also well known in phase transitions in condensed matter systems (and many others, as the Wiki article indicates). So, I was surprised when I saw the title Symmetry breaking and genetic assimilation at Pharyngula. However, after I read those parts that explain symmetry, and its breaking, it sort of makes sense to me. According to Pharyngula,

A hallmark of the Bilaterians, like us and flatworms and fish and cows, is bilateral symmetry: we have left and right halves that are at least superficially mirror images of one another. However, underlying that is a secondary asymmetry. Our hearts are lopsided because one half has a harder job to do than the other; our livers are mostly on one side of our body; and some organisms, such as snails, have a characteristic handedness to their spiral form.

Also, apparently,

There are organisms that exhibit bilateral asymmetries which are not determined genetically; different individuals have right- or left-handed organs, and the parental pattern is not passed on to their progeny.

Makes sense isn’t it? So, evolution is nothing but a phase transition — how the system (species) evolves in response to the changes in the parameters (environment).

In any case, it was nice to see a familiar concept in an area that is very different from mine!

PDFs of public domain books!

August 30, 2006

According to this story from Boing Boing, Google Books offers pdfs of public domain books; and the story also links to Flatland by Edwin Abbott Abbott 😉 Have fun!