• While the text in our “Instant expert” pull-out guide to dark matter (5 February) said that the Z boson transmits the weak nuclear force, the caption on p iv said otherwise. The caption was incorrect.
• In a bungled attempt at clarification of a letter by Valerie Yule about using concert technology to help older people discriminate dialogue (19 March, p 33), we added a sentence saying that compensating for the difficulty of picking out voices from low-frequency background noise “often requires that the radio or television be turned up to a level unpleasant for younger ears”. She points out that “Turning up the volume only makes the noise louder for older ears”. Our apologies for the error.
