• The DOI for Steven Clapcote’s paper on epileptic mice (8 August, p 14) is 10.1073/pnas.0904817106.
• The Planck length – the quantum of distance – is 1.6 × 10-35 metres, not “about 10-33 metres” (15 August, p 26).
Letter: For the record
Published 26 August 2009
Issue no. 2723 published 29 August 2009
