The Zwicker tone is an auditory aftereffect. If you listen to a noise that contains all pitches of notes except for one, then switch it off, you hear the missing tone linger, even though it was never played. This auditory illusion cannot be explained by the apparatus of the ear itself, and must arise in the brain. This paper shows how some simple models of neurons in the brain can show the Zwicker effect. Understanding how the Zwicker tone works should lead to an understanding of how tinnitus, a long-term auditory phantom, occurs.

Journal article: Available to journalists on request

2) Breathing bubbles in DNA zippers
G. Altan-Bonnet, A. Libchaber, O. Krichevsky
Physical Review Letters (Print issue: April 4, 2003)

Have you ever had a zipper with a bubble? The two sides get separated for a few teeth before joining back together. Exactly the same thing can happen in DNA molecules except that in DNA, the bubbles can open and close, a process called "breathing". Physicists have now watched DNA breathing bubbles for the first time by attaching small lightbulbs to the DNA strands and watching them move. (The lightbulbs are actually fluorophores which glow back when illuminated with UV light.) The researchers see that bubbles can move along a DNA molecule with one end closing up as the other end opens. Bubbles can also get stuck in certain places and a variety of sizes of bubbles occur in DNA molecules.

Journal article: Available to journalists on request

3) Origins of solar flares
D. Hughes, M. Paczuski, R.O. Dendy, P. Helander, K.G. McClements
Physical Review Letters (Print issue: April 4, 2003)

You can think of the magnetic field beneath the photosphere of the Sun as a giant ball of yarn. Magnetic flux tubes, like loose threads, a
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Contact: David Harris
harris@aps.org
301-209-3238
American Physical Society
28-Mar-2003