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Showing posts from October, 2009

Optogenetics

This is a little deviation from the usual topic.
Scientist are able to genetically modify neurons that respond to light. They are in fact able to do this in a targeted manner. A patient would then have some LEDs inside his skull, emitting some light. In response the selected neurons start to fire. They demonstrated the technology by making mice run counterclockwise when they turn on the light. This is input to the brain. Earlier, it was demonstrated that neurons can be genetically modified to emit light when they are firing. Are we heading towards rewiring the brain and turning it into a light computer?
The motivation for the research is to cure diseases like Parkinson's disease, when the patient has all the circuity and muscles but is just unable to make the movements. In fact, the researchers are already testing this technology on primates. Source: Wired Nov. 2009, "Powered by Photons" pp. 109--113. The wikipedia entry for optogenetics is here.

Pitfalls of optimality in statistics

I was reading a little bit about robust statistics, as we are in the process of putting together a paper about entropy estimation where robustness comes up as an issue. While searching on the net for the best material to understand this topic (I am thinking about posting another article about what I have found), I have bumped into a nice paper (downloadable from here) by Peter J. Huber, one of the main figures in robust statistics, where he talks about a bunch of pitfalls around pursuing optimality in statistics. Huber writes eloquently -- he gives plenty of examples, motivates definitions. He is just great. I can only recommend this paper or his book. Now, what are the pitfalls he writes about? He distinguishes 4 types with the following syndromes:
The fuzzy concepts syndrome: sloppy translation of concepts into mathematics. Think about uniform vs. non-uniform convergence (sloppy asymptotics). In statistics a concrete example is the concept of efficiency which is defined in a non-unif…