This Friday's collloquium in the Dartmouth physics department might interest
some people on this list:
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COLLOQUIUM
"Does the Magnetic Compass of Birds Involve a Coherent Quantum Process?"
by
Thorsten Ritz
Physics and Astronomy
UC Irvine
ABSTRACT: Many animals, including migratory and non-migratory birds derive directional
information from the geomagnetic field to orient their movements. This magnetic
compass has been well characterized behaviorally, but the underlying reception
mechanism has remained enigmatic. For many years, the use of biological magnetic
materials such as magnetite crystals, had been assumed to underlie biological
compasses. Recently, the suggestion that magnetically sensitive photochemical
radical-pair reactions can provide a basis for magnetic sensitivity has received
renewed attention. The radical pair model proposes a role of spin-selective processes
as the magnetically sensitive step, suggesting a role of quantum physics in a
key biological response. We will review behavioral, spin-chemical, and neurobiological
evidence from our and other groups supporting this suggestion. We will address
how a radical-pair based sensor should be designed to be optimally sensitive to
weak magnetic fields. Finally, we will discuss future avenues of research towards
identifying not only the mechanism, but also the chemical nature of the receptors
underlying magnetoreception, and in particular the photoreceptor chryptochrome,
an emerging candidate for the long sought after magnetoreceptor.
Ritz, T., P. Thalau, J. Phillips, R. Wiltschko, W. Wiltschko. Resonance effects
indicate a radical pair mechanism for avian magnetic compass. Nature 429:177 (2004).
Ritz, T., M.Ahmad, H. Mouritsen, R. Wiltschko, W. Wiltschko
Photoreceptor-based magnetoreception: optimal design of receptor molecules, cells,
and neuronal processing. J. R. Soc. Interface 7:S135-S146 (2010)
Friday, May 13, 2011
3:30 pm 104 Wilder
Refreshments 3:00 pm 103 Wilder
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