2:00 pm Friday, February 26, 2010
Math/ICES Center of Numerical Analysis Seminar: Representation theoretic patterns in three dimensional cryo-electron microscopy by Ronny Hadini (Austin) in ACE 4.304
Three dimensional cryo-electron microscopy (3D cryo-EM, for short) is the problem of determining the three dimensional structure of a large molecule from the set of images, taken by an electron microscope, of randomly oriented and positioned identical molecular particles which are frozen in a thin layer of ice. A solution to this problem is of particular interest, since it promises to be an entirely general technique which does not require crystallization or other special preparation stages. Present approaches to the problem fail with particles that are too small, cryo-EM images that are too noisy or at resolutions where the signal-to-noise ratio becomes too small. In my talk, I will describe a novel algorithm, referred to as the intrinsic reconstitution algorithm, due to Amit Singer and Yoel Shkolnisky, which constitutes a basic step for the solution of the 3D cryo-EM problem. The appealing property of this new algorithm is that it exhibits remarkable numerical stability to noise. My main goal is to give a conceptual explanation, based on representation theory, for the admissibility (correctness) and the numerical stability of the intrinsic reconstitution algorithm. If time permits, I will mention some recent results concerning more elaborate aspects of the cryo-EM problem. This work is joint with Amit Singer (Princeton) and is a part of an ongoing project conducted jointly with Shamgar Gurevich (IAS), Yoel Shkolnisky (Tel-Aviv University) and Fred Sigworth (Yale). Submitted by
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