Science: Theoretically ...
Monday 09 December 1996
Why don't models of ozone depletion in the Arctic match reality? Because, say a team in Paris in the latest Nature, the computer models can't reproduce the tiny variations in spatial distribution of the ozone-eating chemicals. These could account for big discrepancies between forecast and observed ozone depletion around the North Pole, they say. While models work well with the Antarctic, the polar air circulation is less uniform in our hemisphere. To back up their suggestion, the researchers used an ultra high-resolution model to show that ozone depletion really is sensitive to small-scale differences. For the winter of 1994-95, the effect is large enough to account for the Arctic ozone depletion being 40 per cent greater than models predicted.
The River Nile's great bend, where it zigzags from its northerly path to head southwest for almost 200 miles before heading north again, is probably due to tectonic forces. A report in Science based on radar-sensing data from the Nasa space shuttle suggests that the southwesterly movement is comparatively recent, caused by geological uplift from faults in younger rock beneath it. The northwards flow dates from Precambrian strata. So it's not civil engineering to make the cruises longer.
Family-linked cases of Alzheimer's disease tend to occur at an earlier age than the "spontaneous" forms. The role of the genetic link - a gene known as PS2 - is becoming clearer. New US research has found that PS2 mutation produces a molecule which makes neurons more likely to commit "cell suicide" (apoptosis). Perhaps, say the team at the National Institutes of Health in Bethesda, Maryland, the molecule makes neurons more sensitive to the "normal insults" of ageing, adding to the toxic burden in the patients' brains.
Massively fat, diabetic and infertile: it's no fun being a mouse deficient in leptin. That's the hormone encoded by the "Ob" (for obese) gene which helps you lose weight by suppressing appetite and stimulating your metabolism. But as dieters will have suspected, leptin isn't the only player in the weight charades. A neuropeptide called NPY, known to regulate energy balance, reaches high levels in leptin-deficient mice. But mice that don't produce leptin or NPY are less obese than their leptin-deficient mates and suffer less from diabetes or sterility. Gene therapy for weight loss? The day might not be far off. It's just that you would have to mediate a lot of genes.
- 2 Mystery man who gave mum heart-warming note on train 'wanted to put a smile on her face'
- 5 Amal Clooney gives excellent answer to fashion question at European Court of Human Rights
King Salman: Just five days in, Saudi Arabia's new king has already overseen a beheading
Mystery man who gave mum heart-warming note on train 'wanted to put a smile on her face'
Michelle Obama highlights harsh restrictions faced by Saudi women after meeting King Salman without wearing a headscarf
Amal Clooney gives excellent answer to fashion question at European Court of Human Rights
Mafia's wall of silence broken: Victim of Cosa Nostra's extortion rackets in its Corleone heartland co-operates with authorities for the first time ever
'We would evict Queen from Buckingham Palace and allocate her council house,' say Greens
French court convicts three over homophobic tweets, in case hailed as a 'significant victory' by LGBT rights campaigners
Greece elections: Syriza and EU on collision course after election win for left-wing party
British Muslim school children suffering a backlash of abuse following Paris attacks
British grandmother Lindsay Sandiford faces execution by firing squad in Indonesia
Liberal Democrat minister defends comments suggesting immigration causes pub closures
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