Jellyfish serve as a model for bioengineers for the same reason yeast were once so valuable to geneticists: they're simple to deconstruct.

The truth, of course, is that the only necessary and sufficient condition for human beings to murder one another is the simple fact of being human.

Vaccines save lives; fear endangers them. It's a simple message parents need to keep hearing.

When we're awake, cortisol can fragment memories - one reason eyewitness crime scene accounts are so unreliable. But at night that very fragmentation allows creative recombinations of ideas.

The brain sits snugly inside the skull, but it's not a completely flush fit - there is still a layer of fluid between bone and soft tissue that serves as a natural shock absorber. Some shocks, however, can't be absorbed, and when the head gets clobbered too hard, the brain can twist or torque or rattle around inside its skeletal casing.

A close family member once offered his opinion that I exhibit the phone manners of a goat, then promptly withdrew the charge - out of fairness to goats.