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David Fitzgerald worries that the frequency of computer terms in neuroscience indicates a bias in research methods ( Letters , 13 July ). Rest assured that most neuroscientists are careful to make a distinction between the models we use to understand our data and the metaphors we use to explain our work to the general …

You say each proposed wind farm hub in the North Sea will power up to 12 million UK homes ( 20 July, p 10 ). You don't mention how many days of the year there is enough wind for it to power that number, nor how much fuel will be consumed by power stations standing …

Anil Ananthaswamy reports that two different ways of measuring the present-day expansion of the universe produce different values of the Hubble constant ( 20 July, p 34 ). This brings to mind the principle that measurement changes the phenomenon observed at the quantum scale. The current mess of string theory suggests this may be happening …

I love all your articles about the 1969 moon landing ( 13 July, p 36 ). I was a close observer at that time at Electronic Associates , a company that helped it happen. Digital computers of that time weren't fast enough to do the critical calculations determining the time to ignite the engines and …

Simon Ings observes that The Hummingbird Project is scripted and filmed like a true-life story, and asks who would make up a thriller about high-frequency trading infrastructures ( 13 July, p 30 ). He says the film springs entirely from the head of writer-director Kim Nguyen. Has Nguyen not read Flash Boys: A Wall Street …

Graham Lawton praises London's self-declared status as a National Park City ( 20 July, p 24 ). Born and raised in the South Wales valleys, I have always felt the lure of green spaces. Lawton made me realise that I associate London as strongly with birdwatching and strolling around Hyde Park as I do with …

Lawton praises London as the world's first National Park City. In Finland, we have nine National Urban Parks, created under the Land Use and Building Act of 1999 . At present, Helsinki is in the long and tedious process of trying to decide whether to join places such as Turku, Forssa and Kuopio.

I was shocked by Lawton's claim that the artificiality of ecosystems dominated by invasive species doesn't matter. He notes that Hawaii is now a hotchpotch of mostly invasive and introduced species. That's true – and the harm caused is incalculable. More than half of honeycreepers, a group of bird species endemic to Hawaii, have gone …

Vijay Koul's experience makes him concerned about the viability of willow seeds (Letters, 13 July ). Indeed, they are generally very short-lived in natural situations. For several years, we have been developing a protocol for long-term storage of Salicaceae species at the Millennium Seed Bank . This procedure addresses all stages, from seed collection in …

I found Helen Thomson's report of findings that one in 10 people in vegetative states may be conscious very interesting ( 29 June, p 38 ). On 30 December 1990, I experienced a severe head injury in a car crash. I was placed in an induced coma, so I was more deeply unconscious for the …