A recent literature search had Jennifer Rohn, a posdoc at University College London, seeing double. On her Nature Network blog, Mind the Gap, she describes how she turned up what seemed to be the exact same paper, with the same author list, published in two journals (http://go.nature.com/SDZ8Ja).

On closer inspection, Rohn finds that the two papers are identical. One is published in Cell, whereas the other features as a chapter in a meeting proceedings book. “How common is this sort of double publication? And how do people feel about it?” asks Rohn, opening up a lengthy discussion.

Those commenting speculate that the book chapter was an obligation filled with an easy, already-finished manuscript or that a junior author submitted the second version without the senior author's knowledge. One commenter wonders whether a duplicate set he found should be turned in as scientific misconduct. Meanwhile, on a related note, another person observes that publishing papers in different languages reaches more readers. Doubling up, it seems, is a grey area of scientific publication.