Nature Publishing Group will begin depositing manuscripts into PubMed Central six months after publication on behalf of authors, starting later this summer, according to a release. But some open access publishing advocates say this is just a way for the publisher to maintain an embargo period, rather than making content immediately available.

Earlier this year the National Institutes of Health issued a mandate that required all biomedical research papers sponsored by NIH funds to be deposited in PubMed Central within 12 months of publication. Many publishing groups have objected to this mandate, saying that it violates their copyrights and publishing models.

David Hoole, head of content licensing and brand marketing at Nature, told The Scientist that the free service is meant to help authors comply with the NIH mandate. Authors will decide whether to have Nature deposit for them into PubMed Central during the article submission process.

Nature has assembled a team of about half a dozen people, including a new head of author services, to manage the PubMed Central submissions, and Hoole said they are devoting significant resources to make sure it's done right.

But some open access advocates question Nature's motives. The purpose of this new service is to "lock in [Nature's] embargo," Stevan Harnad, cognitive scientist at the University of Southampton, UK, and vocal open access supporter, told The Scientist. Nature is hoping, he added, that if given the choice, authors will choose the convenience of letting Nature deposit for them after six months, rather than take the time to do it themselves immediately.

"We believe that the top level journals operate better under a subscription model rather than free publication model," Hoole said. "The six-month embargo protects a subscription model, more than a zero [cost] model does." During the six-month embargo, people still have to pay to read Nature content.

Authors should not need the convenience of having someone else deposit for them into PubMed Central, Harnad added. His group calculated that it only takes six minutes on the authors' parts to deposit final, peer-reviewed papers in PubMed Central.

Some institutions, like Harvard University, have adopted their own mandates, requiring authors to deposit accepted manuscripts into a university repository immediately. In the case of Harvard, Nature offered to help them populate their repository but Harvard refused to accept Nature's six-month embargo, Hoole said. So authors getting published in Nature have gotten exemptions from their university to submit to the institutional repository.