• Our report about photonic crystals (28 July, p 28) should have attributed their properties to an array of micro-spheres, not of atoms.
• We wrote: “Even in eastern Europe abortion rates have halved from 90 abortions per 1000 women in 2005, to 44 per 1000 in 2003” (20 October, p 8) That should have been “90 abortions per 1000 women in 1995…”.
