Letters archive

While your article on regulation of the oestrogen mimic bisphenol A (23 October, p 26) was in press, Canada declared BPA "toxic". Under North American Free Trade Agreement rules, affected parties in the US can challenge this ruling on the grounds that it restricts trade within NAFTA. It will be interesting to see how this …

Thank you for the all-too-brief article on super-evolution among the "50 Ideas" ( 9 October, p 32 ). It is clear enough to me that surviving millions of years is about resilient ecosystems, not selfish individuals. Even bacterial mats seem more aware of their community responsibilities than selfish capitalists. Looking at the heterogeneous colonies walking …

Brian Bowsher, celebrating SI units' anniversary, states that all bar one "have been defined by universal, natural constants" (30 October, p 29) . But one SI base unit, the metre, is defined in terms of light travel based on another SI unit, the second. While the speed of light might be a universal, natural constant, …

I was fascinated to learn that trauma experienced by mice can affect their offspring through epigenetic transfer (6 November, p 8) , but searched the article in vain for one name: Jean-Baptiste Lamarck. Since he died before Darwin published On the Origin of Species , he did not get the chance to adjust his theories …

For 50 years we were assured that our ancestors became bipedal and naked as a result of living on the savannah. More recently it has been established that they became bipedal before they ever lived on the savannah. Why then did we ever acquire this unique form of locomotion? Your eight-page guide to human origins …

You seem to exaggerate the problem of solar power overloading the electricity grid (30 October, p 4) . I understand that buildings with solar panels draw power from the grid when they need it but may supply it to the grid if they generate more than they need. I can't believe it is beyond the …

The problems outlined in your article on hybrid helicopters (16 October, p 20) have been solved several times during the history of flight. One notable British example was the Fairey Rotodyne, designed in the 1950s by the same company that produced the Swordfish torpedo bomber, used by the Royal Navy in the second world war. …

Some writers in your section "Science wakes up to morality" ( 16 October, p 41 ) clearly feel they are engaged in territorial wars against philosophy and religion. Several contributors, notably Patricia Churchland, plainly think that neurobiological explanation supersedes all other kinds of inquiry. But would a detailed account of the brain states used in …

Evelyn Fox Keller's apparent dismissal of the use of statistical analysis to resolve the nature/nurture debate is too sweeping (18 September, p 28) . Imagine you could take a random sample of embryos and environments from a given community and try out all combinations of genes and environment. Standard regression tests would reveal which has …

Your article about the healing power of pets (6 November, p 30) reminded me of a visit I made to a Reform synagogue in Boston one Friday evening this summer. I was most surprised to see that one of the congregants, sitting quietly in the front row next to some children, was a small white …

• The cyber-security test range in Fareham, Hampshire, UK, is not a Ministry of Defence facility as we mistakenly implied. It was built, is owned and was opened by Northrop Grumman, with defence minister Gerald Howarth MP as its guest of honour (23 October, p 21) .