Archive for September, 2007
Power Laws in Arid Ecosystems
Recently in Nature: Two papers claiming to find power-law distributions in the patch sizes of vegetation. [1,2] Using field data from arid Mediterranean regions, Kefi et al found a power law distribution (, where N is the number of patches and S is the patch size) for areas with low grazing, and a truncated power [...]
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Modelling Ethnic Violence
A new paper* in Science purports to predict patterns of ethnic violence from simple assumptions of inter-group dynamics, ignoring all institutional and historical factors peculiar to the situation. Their assumptions are as follows:
1. Individuals preferentially move to areas where more individuals of the same type reside.
2. The size of patches of each type grows as [...]
Filed under: mathematics | Leave a Comment
Journal Club Update
We’re having a journal club tomorrow (or first session ever) at 730pm at Matrix in Biopolis. If you’d like to come, drop us a reply here or just send us an email. We’re looking at graphene tomorrow.
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A New Kind of Swallowing
For some organisms, one set of sharp teeth is not enough. Imagine having these in your throat:
Those are the second set of jaws possessed by moray eels, according to this paper in Nature.* There are even videos here and here where you can actually see the secondary jaws shooting out to pull the prey down [...]
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quantum mechanical eigen-problem
All materials have properties that can be attributed to the nature of their chemical bonds. A table is hard and stiff primarily because the bonds and the arrangement of atoms with their bonds are hard and stiff. A liquid is fluid like because the intra-molecular forces are negligible or there exists no bonds between the [...]
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In this paper by Bru et. al. , the universal dynamics of tumor growth, an experiment measuring the topological roughness of tumors grown both in vivo and in vitro is presented. The cell lines were of colon adenocarcinoma. They found that the local roughness obeyed a scaling law with critical exponents corresponding to a familiar growth kinetics [...]
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Benjamin Libet, 1916-2007
I first read about Benjamin Libet’s famous experiments ‘disproving’ the existence of free will in Daniel Dennett’s outrageously named (but excellent) book Consciousness Explained (I was once at a book signing in Chicago where Daniel Dennett, promoting his psychology/sociology of religion book Breaking the Spell, mentioned that he thought Pascal Boyer’s biology/anthropology of religion treatise [...]
Filed under: psychology | 1 Comment
Hermann Weyl’s Space Time Matter
The blurb says that Nature calls this book “The standard treatise on the general theory of relativity”. I’m only 42 pages into it but I’m ready to vouch that it’s the most outstanding physics/math text I’ve encountered. I’m a fan of verbal exposition over terse mathematics, as long as said verbal exposition is accompanied by [...]
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Is Menopause Adaptive?
A short comment in TREE by McAuliffe and Whitehead [1] suggest the occurrence of menopause in some species of whales as evidence for the adaptive role of menopause in humans. Why? Well, we we have no idea if humans in the pre-modern age (before written records of menopause and so on were possible) experienced menopause. [...]
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The Dimensionality of Spacetime
I was pointed to this old-ish paper by Max Tegmark [1] by a draft philosophy paper that used some of its results. Tegmark tries to answer the question of why there are three dimensions of space and one dimension of time. As usual, I do not completely understand the math, but I can grasp enough [...]
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