Editorial: APS now leaves copyright with authors for derivative works
http://link.aps.org/abstract/PRD/v78/e080001

“When you submit an article to an APS (American Physical Society) journal, we ask you to sign our copyright form. It transfers copyright for the article to APS, but keeps certain rights for you, the author. We have recently changed the form to add the right to make ‘derivative works’ that reuse parts of the article in a new work. ”

The importance of this change is discussed in the link above…

“the APS has been very generous, by the standards of journal publishers, in giving rights to its authors to use their articles as they wish…In the new agreement, copyright rests with the author for derivative works that contain at least 10% new material and not more than 50% of their article that is published in an APS journal. We believe that this will allow authors sufficient freedom to reuse material from their articles in APS journals when writing for a new audience, while protecting the APS from wholesale copying of our content.”