Â鶹´«Ã½

During the SARS outbreak, I have become deeply concerned by the failure of medical professionals to understand basic statistics. By 14 April, 1190 people had contracted SARS and 47 of these had died. Such numbers have been widely cited as meaning there is a 3.9 per cent chance of death. The calculation is this: the …

I'm glad to see that Â鶹´«Ã½ is drawing attention to the immediate and longer-term dangers of widespread contamination with depleted uranium munitions in Iraq, and previously Kuwait and Kosovo (19 April, p 4) . However, there are a few points I'd like to direct your readers' attention to. Saying that tank shells are "tipped …

You cite a three-day study showing that any beverage is as effective for keeping the body hydrated as eight glasses of plain water (5 April, p 26) . Water is passed through the kidneys, whose jobs include maintaining proper balances of water and many different acids and salts in the body, and removing toxins and …

The arguments about genetically modified crops seem to be based on the proposition that it is possible for the technique to be proved either safe or unsafe (5 April, p 44) . This is in the interests of the proponents of GM organisms, because once you accept the idea that altering the genetic code of …

Your correspondent Tim Lister, in failing to see the necessity for better spam filters, has himself missed the point (12 April, p 28) . Whitelisting (the practice of only accepting mail from known sources) does not work because many email users, especially businesses, expect – indeed, wish to – receive mail from people they do …

I thought you might be interested to know that in 1956, IBM – which was then heavily into timekeeping systems – developed a pendulum clock that was radio-controlled by a short-wave signal from the National Institute of Standards and Technology radio station WWV. The concept for this clock was about the same as that described …

The example of room-temperature superconductivity that you report is unconvincing (12 April, p 17) . It is clear from the original paper by Johan Prins that it would be quite impossible to detect superconductivity with his measurements. In his experiment he found that the current through his crystal did not change detectably when the thickness …

The article on flower-shaped crystals of indium nitride suggested these were the first flower-shaped crystals to be created (1 March, p 15) . In fact, this is a good example of man imitating nature. Natural, flower-shaped crystal groups much larger than the bonsai crystals you illustrated have been known to mineralogists for centuries. For example, …

We were gratified to read your report of the "new" tuberculosis test that could soon replace the familiar 100-year-old "tuberculin skin test" (12 April, p 21) . Your readers might like to know that a very similar test already exists, has been approved by the US Food and Drug Administration and was launched worldwide years …

Discovering the reason behind the counter-intuitive effect of damage to the brain as it floats in its saline solution was brilliant work (5 April, p 21) . However, there is a very simple experiment anyone can do to give the same fascinating result. Buy a helium balloon with a ribbon, tie it down in a …

Following up your correspondence on pubs with names like The Office (29 March, p 30) , has anybody told you about the little town of Chatteris in Cambridgeshire where there is a very handy pub called Walk the Dog? "Yes, dear, I'm just going to…"