Stripping Down Science Read Free

stock from which modern dogs derive originally.
The difference between a dog and a wolf amounts to about 15,000 years of selective breeding by humans. The fact that just three genes account for the coat differences across such a broad range of dog breeds shows that, in each case, single mutations have produced each coat trait and have subsequently been bred by us into all of the other dogs around today.

    FACT BOX
    Cats have their owners under their paws
Those who prefer to keep a cat rather than man’s more traditional best friend, beware. Your moggy may well be resorting to mewing-related manipulation to tap into your sensitive side.
According to Sussex University scientist (and cat-owner) Karen McComb, 8 there are two ‘flavours’ of purring: one when a cat is contented and a second ‘solicitation’ sound produced with ‘purr-pose’ such as when the animal is after something. ‘In my cat’s case, it’s usually at 5 am when it wakes me up wanting to go out,’ says McComb.
To find out whether humans fall for this feline trick, she recorded the purrs of 10 cats and played them to a group of 50 volunteers, which included both cat-owners and non-cat-owners. Participants from both groups pricked up their ears at the solicitation purrsand judged them to be more urgent-sounding, distracting and unpleasant.
To find out why, McComb acoustically analysed the two purr types and found a significant difference. A contented cat produces a steady purr that rumbles along at about 27 Hz, just above the threshold of human low-frequency hearing. But a cat craving attention or food adds an extra sound – effectively a ‘mini-meow’ nestled inside the ongoing purr. Intriguingly, this 380 Hz additional sound is within the same frequency range as a human baby’s cry, which we all know from bitter experience is very distracting. The effect also appears to be more manifest amongst cats that have a close one-to-one relationship with their owners.
This suggests that, once they get to know you, cats craftily tap into a sonic sensitivity linked to your child-nurturing instincts, meaning you’re more likely to feed them than throw them out …

Recession, depression, repossession, febrile economy, credit crunch, quantitative easing … Few have escaped the headlines, or the impact, of the financial crisis that’s gripped the world in the latter part of the ‘noughties’. Given the grim state of the world economy, you’d be forgiven for thinking that just about the only people who might profit from a recession are bailiffs, bankruptcy lawyers and newspaper publishers with a penchant for monetary puns and wordplays. But there is a silver lining to the present gloomy outlook: your health is likely to be a beneficiary too!
    This sounds counterintuitive, because we’re always being told that prosperity makes people live longer. But it turns out this is a myth of almost similar proportions to Barack Obama’s US rescue package. Instead, it’s official: new work has shown that, alongside share prices, death rates drop during a recession.
    This relationship was revealed when Jose Tapia Granados and Ana Diez Roux, both based at theUniversity of Michigan, 9 compared mortality rates with the state of the US economy over the period straddling the 1930s Great Depression, with striking results. In the years 1923, 1926, 1929 and 1936–37, they report, there were economic booms. But in each of these years, the population mortality rates also peaked. However, in 1921, 1930–33 and 1938, which were all recessions or depressions, the death rates among children and adults fell to their lowest levels. Initially this seems surprising because one would assume that, during recessions, people would be financially stretched, have little money for healthcare and healthy living and would be generally more stressed, all of which would add up to a higher risk of dying. It seems