More than an eon ago, the sun shone dimmer than it does today, but the Earth stayed warm due to a strong greenhouse gas effect, geoscience theory holds. Astronomer Carl Sagan coined this “the Faint Young Sun Paradox,” and for decades, researchers have searched for the right balance of atmospheric gases that could have kept early Earth cozy.
When dehydration strikes, part of the brain can swell, neural signaling can intensify, and doing monotonous tasks can get harder.
By analyzing genomic sequences from more than 400 strains of the bacterium that causes anthrax, researchers have provided the first evidence that the severity – technically known as virulence – of specific strains may be related to the number of copies of certain plasmids they carry. Plasmids are genetic structures of the cell that can reproduce independently, and are responsible for producing the anthrax toxin and other virulence factors.