Snuff hazard
Cancer-causing chemicals thought to be absent from smokeless tobacco products are present in moist snuff, a mouth tobacco mostly used in North America. At an American Chemical Society meeting, Irina Stepanov at the University of Minnesota reported that a dose of moist snuff delivers the same quantity of polycyclic aromatic hydrocarbons as five cigarettes. A similar form of tobacco, called snus, is popular in Scandinavia, but is not smoke-cured like the American version. Both kinds are banned from sale in all European Union countries except Sweden.
Global tilting
The tilt of Earth鈥檚 axis will change with global warming. If atmospheric carbon dioxide levels were to double by 2100, expansion of the warmer oceans would shift the Earth鈥檚 spin axis by roughly 1.5 centimetres per year (Geophysical Research Letters, ).
DNA evidence that lies
DNA evidence could be faked and planted at crime scenes, say researchers from Nucleix in Tel Aviv, Israel, which is designing tests to distinguish between authentic and deliberately contaminated samples. They showed how DNA left on an item, or constructed to match a known profile, could be turned into a blood or saliva sample.
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Self-medicating lambs
Lambs with a stomach parasite have been found to eat more food that is low in nutrients but high in antiparasitic tannins than healthy lambs do. After the parasite had cleared, the animals switched back to their normal diet, suggesting they self-medicate by changing their eating habits (Behavioural Processes, )
Nerve centre
Do all central nervous systems have the same origin? The soil-dwelling acorn worm has centralised nerves, both at its back and its front. As vertebrates have their CNS at the back, and invertebrates at the front, the worm may represent a transition between the two (Current Biology, ).