The explanations, particularly in the thorny field of quantum physics, are excellent, and the selection of subject matter skilfully winnows a vast field.

ECONOMIST: History of science: Time's arrow | The

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BBC: Health threat from computer use

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BBC: Ireland suffers identity crisis over neutrality

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BBC: Kenya split by wedding row

What they have found is that about 1, 800 protein-coding genes, some 7% of the total known, show signs of having been subject to recent natural selection.

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Cricket gives them the opportunity to watch world-class sportsmen, and the game is now well enough entrenched to have become the subject of bitter wrangles over team selection, and the skills of the coach, the former West Indian batsman, Gordon Greenidge (who was granted Bangladeshi citizenship after the national team qualified for the World Cup).

ECONOMIST: Meet the minnows

It would include a range of A-levels, with an expectation that pupils would study a less narrow selection of subjects - such as studying sciences with an arts subject.

BBC: A-level students facing shake-up

He said there was no guarantee that introducing a specific genetic change would have much impact in a population which was subject to the effects of many other natural selection processes.

BBC: The malaria parasite is spread by mosquitoes

The site also links to a wide selection of Halloween-related web pages, covering All Hallows' Eve subject matter from ghost stories to costumes to "mystic games" like a virtual Ouija board and a tarot card reading.

CNN: Halloween spirits are on The Web

Rather than a traditional trial setup, his patients pay tens of thousands of dollars for the privilege of participating in the studies (not the most ethical or effective subject selection strategy).

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