19 August 2005
Vol 309, Issue 5738

About The Cover

Cover image expansion

COVER A crystal of colloidal particles far below its melting temperature. A grain boundary rises diagonally from left to right, separating sections of the crystal with different orientations. Circles denote the time-averaged position of each particle, with red indicating a lower degree and blue a higher degree of positional fluctuation about its equilibrium position. See page 1207. [Image: A. M. Alsayed et al.]