Letters archive

While we don't know whether parallel universes exist, there is something we do know: whenever a physicist writes a book about them, the web erupts with claims they are unscientific nonsense. Mark Buchanan's review of my book Our Mathematical Universe was no exception (18 January, p 46) . "Is this still science," he wonders, "or …

The views of ecologist Chris Thomas on the resilience of the biosphere were refreshing and long overdue (11 January, p 28) . As he points out, extinctions, hybridisations and the generation of new species are fundamental to the constant fine-tuning of Earth's biosphere, and offer some consolation in the face of fears of species decline. …

In her letter, Weibina Heesterman fears that new life forms evolving after a human-induced mass extinction event "might be a glut of insect forms rather than cuddly koala-type creatures" (1 February, p 33) . Yet the evolution of new species of insect and other invertebrates would hardly be surprising considering that they will also be …

I enjoyed your look at sugar's health effects, and was fascinated by the statement that "fructose doesn't affect leptin production ; one small study even suggests it ups the level of its counterpart ghrelin, the hormone that makes you hungry". In other words, fructose encourages overeating (1 February, p 34) . This fits my experience …

Discussing Fyodor Dostoevsky's epilepsy, Anil Ananthaswamy asks if mystics through the ages had comparable "ecstasies" (25 January, p 44) . Seven decades ago, historian Joseph Klausner's book From Jesus to Paul outlined reasons for thinking that St Paul had epileptic seizures. In 1987, David Landsborough developed this diagnosis in the Journal of Neurology, Neurosurgery & …

I enjoyed the article on nitrogen-hungry pitcher plants and their relationship with defecating mammals (1 February, p 43) . But I am not 5 years old so don't need the prissy and childish word "poo" to assault my eyes. Excreta, faeces or droppings are perfectly acceptable; dung is perhaps not, as it implies manure. Shit …

The notion of using high-intensity focused ultrasound waves in cancer surgery sounds interesting (4 January, p 38) . However, as a pathologist, I have some concerns. You can make a case for sonic waves cooking an in situ tumour to oblivion, but in practice the inspection of a removed tumour remains important in order to …

Based on the assumption that brainstem death means life has ended, I would draw the opposite conclusions to medical ethicist Richard Huxtable in his look at the debate over life support for pregnant Marlise Muñoz and teenager Jahi McMath in the US. Both were diagnosed brain dead (25 January, p 26) . There was a …

• Muñoz's fetus was not viable. The Texas hospital involved has now ended life support on the orders of a state district judge.

I used to reject the concept of intergenerational memory transfer that John O'Hara highlights in his letter (18 January, p 29) . Then I woke up. I have a pointer, my fourth. These dogs were bred to find birds, and then on command, get the birds to break cover so they could be shot. None …

The crops listed in your article championing the urban vertical farm as a "new, environmentally friendly way to feed the rapidly swelling populations of cities worldwide" are lettuce, spinach, kale, tomatoes, peppers, basil and strawberries (18 January, p 17) . Tasty, but no rice, wheat, maize or potatoes. Sounds more like garnishings for the wealthy …

Alan Coulson says his Morris Minor car could evade a new system that disables the vehicles of uncooperative drivers by firing radio pulses at them (25 January, p 31) . I also own one, but would like to note that Morris Minor drivers are seldom the target of a police pursuit and in any case …

Liam Drew's article advising of a decline in dementia rates is welcome news (11 January, p 32) . I've worked for four years in caring for older people. Daily I see the ruination of lives that dementia brings. I'm convinced that high levels of stress hormones, called corticosteroids, are responsible for the ravages to the …

I was fascinated to learn about Markus Buehler's use of musical structures to improve the design of materials (1 February, p 30) . That set me thinking: what novel structures and materials might already lurk undetected in the huge library of musical compositions? I feel an app coming on, for hooking up a 3D printer …

John Cryan and Timothy Dinan's article on the links being demonstrated between various psychological problems and particular strains of gut bacteria is encouraging in its suggestion that these may provide future treatments (25 January, p 28) . However, the jump to suggesting that the ideal treatment may be a genetically modified organism containing genes from …

Cryan and Dinan show that our gut flora powerfully affect us. Despite some counter examples – infections and the success of faecal transplants – our flora seems to be either self-managing or managed by us, for example through diet. It would be good to know how much of which, and whether we can intervene in …

• We briefly lost our bearings in our look at Braess's paradox (18 January, p 30) . Physicist Adilson Motter is at Northwestern University in Evanston, Illinois, not Northeastern University.