Letters archive

While I agree population mobility and urbanisation are contributing factors to the size of the current Ebola outbreak (9 August, p 6) , it is important to stress that there are many factors at play. I recently returned from Guéckédou, Guinea, where I worked with the World Health Organization's Global Outbreak Alert and Response Network. …

Your recent cover story explores what it would mean to fly in an aircraft without a human at the controls (9 August, p 30) . While it will certainly be possible to build autonomous passenger aircraft, the majority of airports would be unable to handle them. In order that aircraft can execute an automatic landing, …

Paul Marks's excellent article on pilotless aircraft inevitably recalls the famous joke told to the Royal Aeronautical Society by the late, great Peter Masefield . It concerns the world's first automatic landing on scheduled services by a BEA Trident on 10 June 1965. The pilot drew attention to this historic first, and assured the passengers …

Fred Pearce is right to highlight the disagreement over how electricity should be delivered to the world's poorest people (2 August, p 26) . However, he is wrong to reiterate the idea that widespread adoption of solar panels might lock poor communities into a future that is "low-energy and low-income". The answer is quite simple …

I once worked as the manager of a small electricity company in south-west Uganda. We supplied a hospital and the community using hydroelectricity, but the supply was limited and so we needed to promote alternative sources too. The first need in homes is for lighting and telephones, which can be provided by solar power. Homes …

The jury is still out on the link between saturated fat and heart disease, according to Jon White (2 August, p 32) . While this is a reasonable conclusion, dairy fat has been increasingly vindicated by a series of large, long-term studies. Drinking milk has been shown to be associated with a small but worthwhile …

One of the best simulations of long-haul space flights and planetary habitats may well be saturation diving (2 August, p 13) . There are now years of experience of the process, which contains most of the elements of space travel, including cramped and unpleasant surroundings in complicated tubular habitats, limited washing and toilet facilities, poor …

The southern Gulf of California in Mexico offers an opportunity to observe rogue waves on a small scale (26 July, p 42) . Gale-force north winds blow for days in winter, raising waves of 2 metres that are interspersed with 6-metre-high rogues, all travelling in the same direction. The rogues travel almost intact across wide …

I enjoyed Michael Brooks's feature exploring California's water problems (26 July, p 36) . The proposed $25 billion pipeline to address water shortages will not provide any additional water, and may cause more problems than it solves. A better solution is desalination plants to get water from the Pacific Ocean. The San Francisco Chronicle reported …

In arguing for access to a greater variety of therapies on the UK National Health Service (NHS), Sian Lloyd makes claims that I think are contradictory (26 July, p 30). She says that therapists who are able to choose from a wider range of therapies are more likely to help people, while at the same …

Readers have recently discussed athletes' use of xenon as a performance-enhancing substance (26 July, p 31) . The gas has been classified appropriately as a drug for many years. When administered in sufficient concentration with supplemental oxygen, xenon is a potent general anaesthetic. Its high cost is the principal reason it is not used in …

Jihadi threats surely arise from basic differences in philosophy between people (26 July, p 30) . This is a problem of fundamentalism, a term which applies to the many religions which require strict adherence to a particular interpretation of an established text. Such differences will not be resolved by military or punitive actions, which are …

Jacob Aron's article on bird flocks behaving like waves reminded me of something I observed a few years ago (2 August, p 16) . I saw two flocks, one of gulls and one of crows, of about 20 birds each. They were making a lot of noise because the flocks were on a collision course. …