The researchers estimated global water vapor flow from land at 67,000 km3/year. Deforestation has led to a 3,000 km3/year decrease in water vapor flow, while irrigation has caused an almost equivalent increase.

On a global scale, decreases in water vapor flow due to deforestation cancel out increased flow associated with irrigation. However, the spatial pattern of water vapor flow has changed substantially, leading to major regional effects obscured in global estimates. In areas where increased food production leads to both widespread deforestation and irrigation, as in the Indian Ocean basin, the change in vapor flow may trigger disruptions of the Asian monsoon system.

The researchers suggest that such land use changes need to be considered when developing climate models.

Potential Pheromone Activates Brains of Homosexual Men

A potential pheromone found in male perspiration activates the brains of homosexual men and heterosexual women in a similar manner, researchers report.

While it is unclear if humans respond to pheromones, candidate compounds include a testosterone derivative called 4,16-androstadien-3-one (AND), and the estrogen-like steroid estra-1,3-5(10),16-tetraen-3-ol (EST).

In a previous study, Ivanka Savic and colleagues demonstrated that the hypothalamus region of the brain becomes activated when men smell EST and women smell AND, but not vice versa.

In the current study, the researchers examined whether brain activation patterns induced by EST and AND corresponded with sexual orientation, rather than with biological gender. The scientists compared brain activity between homosexual men, and heterosexual men and women, in response to smelling EST, AND, and ordinary odors, such as lavender.

The researchers observed that AND activated the hypothalamus in homosexual men and heterosexual women, but not hetero
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Contact: Leikny Johnson
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Proceedings of the National Academy of Sciences (PNAS)
9-May-2005