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Why Polio Isn't Going Away

As the number of cases of the paralytic disease fall, world health officials have to grapple with a vexing problem: a component of the most widely used polio vaccine now causes more disease than the virus it is supposed to fight

By Helen Branswell

The Limits of Breath Holding

It's logical to think that the brain's need for oxygen is what limits how long people can hold their breath. Logical, but not the whole story

By Michael J. Parkes

Quantum Gravity in Flatland

Imagine space were 2-D rather than 3-D. How would the force of gravity work? The surprising answers are guiding physicists to a unified theory of nature

By Steven Carlip

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