Letters archive

James Clarage's calculations of Google's energy usage assume that all their "nearly a million" servers do is perform searches (3 April, p 20) . In fact, Google uses these data centres for many things: hosting YouTube and Gmail, caching just about every web page in existence and being one of the world's largest web advertisers …

In her letter on the ability of the peer-review process to effectively challenge scientific dogma, Deepa Coleman notes that "there is no such person as a disinterested scientist". In the next letter, Bruce Denness states: "What peer review guarantees is the attainment of mediocrity in the most efficient way" (20 March, p 24) . Combining …

In discussing the conservation management of Cousin Island (24 April, p 36), Graham Lawton says the island was bought from "the Seychelles royal family" in 1968. In fact, the island was purchased by BirdLife International from a Mrs Jumeau , whose husband had run it as a coconut plantation. The article is also mistaken in …

In your compendium on human endurance, Graham Lawton asserts that there are no records of a person having been killed by intentional sleep deprivation (17 April, p 37) . There may not have been any scientific experiments, but there is a well-documented case from classical history. Perseus, the last king of Macedon, after being captured …

Ian Gilbert cites many examples of how civilian life has benefited from military scientific advances (17 April, p 25) but he misses a subtle point: military spending does not in itself increase the number of innovators, it just excludes them from the constraints of the civilian market. Military activity itself depends on the existence of …

In calculating the payback times for investment in alternative energy systems (27 March, p 46) , Ed Douglas used an erroneous assumption. He stated, for example, that payback for the photovoltaic system costing £11,000 would take 55 years, so that you recoup £200 per year. Such calculations assume that a single rate of inflation applies …

Wendy Zukerman reports that old folks might be grumpier than younger people because their brains have a reduced ability to cope with stress (10 April, p 10) . Being in my mid-70s, I have considered the question at length. My theory is that, as we become increasingly aware of our mortality, we redefine the things …

Miroslav Hundak states that physical changes in the brain create variations in conscious experience, proving that consciousness must be controlled by the physical properties of the brain (10 April, p 24) . However, if we take a mechanistic analogy we see that the correlation may not be causal. An engine could be running perfectly, despite …

I read with interest the article about the "brainstorming" session sponsored by MIT and Sandia National labs last month in Washington, DC. Phil McKenna wrote that the "world's leading experts" on using boreholes to bury nuclear waste got the idea that with this disposal method we could safely bury radioactive material all over the US …

• Contrary to the caption for the map in our article on mass extinction, Jersey is one of the Channel Islands, and is not part of the UK (24 April, p 38) . • It is hydroxyl radicals, rather than ions, that would oxidise sulphur dioxide emitted from the Toba supervolcano (17 April, p 28) …