About 200 years in the Western United States, according to a study in Nature Geoscience.
More strikingly, Archaeopteryx appeared in the same group, according to the study in Nature.
The study in Nature Neuroscience was small and didn't test anyone under the age of 50.
William Sutherland, the author of a study in Nature magazine last spring, compared the die-off to an environmental catastrophe.
A recent study in Nature suggests that there are more of these potentially threatening small meteors than we previously thought.
The extra synthetic DNA forms a third base pair, X-Y, according to the study in Nature.
Ankur R. Desai of the University of Wisconsin-Madison, an author of the study in Nature Geoscience, said the effect was due to ice, or lack of it.
Dr Adam Rutherford, presenter, Inside Science, Radio 4 3 December Earlier this month, publication of a study in Nature sent shock waves through the science of human origins.
Tiny particles in the second cream diffuse the light and give the layer a youthful appearance, according to a study in Nature Materials.
A study in Nature Geoscience suggests that northern bogs may lose a significant portion of their peat as global temperatures rise.
But a study in Nature Geoscience suggests that while drought may lead to the worst incidences of burning, land use and population density also play roles.
