Poor Mojo's Newswire

Cannabis smoke is well known to be more harmful to the lungs than tobacco, because smokers inhale cannabis one-third more deeply and hold it in their lungs for up to four times as long as cigarette smokers do. Yet while we have a list of more than 4000 chemicals and toxins present in tobacco smoke from dozens of studies, there is no comparable list for cannabis.

So David Moir of Health Canada and his colleagues set out to make a direct comparison, using machines that "smoke" the cigarettes and then collect and analyse the smoke. They found that directly inhaled cannabis smoke contained 20 times as much ammonia and five times as much hydrogen cyanide as tobacco smoke.

Liz Hawkins of the Whale Research Centre at Southern Cross University in Lismore, New South Wales, Australia, eavesdropped on bottlenose dolphins living off the western coast of Australia for her three-year study.

"This communication is highly complex, and it is contextual, so in a sense, it could be termed a language," says Hawkins, who presented her work at a meeting of the Society for Marine Mammalogy in Cape Town, South Africa, this month.

At the same time, researchers studying the microbes that could infect astronauts recently found that at least one, salmonella, becomes significantly more virulent in weightlessness.

"The question of immunity is a potentially big problem for astronauts on long trips and those who may be living on the moon in the future," said Millie Hughes-Fulford, a former astronaut who is researching the effects of "microgravity" on immunity. Her NASA-supported research has led her to conclude that weightlessness itself is a major cause of the problem.

In the past 5,000 years, genetic change has occurred at a rate roughly 100 times higher than any other period, say scientists in the US.

This is in contrast with the widely-held belief that recent human evolution has halted.

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"Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin," he added. "We are getting less alike, not merging into a single, mixed humanity."

This is happening, he said, because "there has not been much flow" between different regions since modern humans left Africa to colonise the rest of the world. And there is no evidence that it is slowing down, he added.