Proceedings of the National Academy of Sciences

Overview
The Proceedings of the National Academy of Sciences of the United States of America, usually referred to as PNAS, is the official journal of the United States National Academy of Sciences. PNAS is an important scientific journal that printed its first issue in 1915 and continues to publish highly cited research reports, commentaries, reviews, perspectives, feature articles, colloquium papers, profiles, letters to the editor, and actions of the Academy. Coverage in PNAS broadly spans the biological, physical, and social sciences. Although most of the papers published in the journal are in the biomedical sciences, PNAS recruits papers and publishes special features in the physical and social sciences and in mathematics. PNAS (abbreviated Proc Natl Acad Sci USA for referencing and indexing purposes ) is published weekly in print, and daily online in PNAS Early Edition CODEN: PNASC8.

History
PNAS was established by the National Academy of Sciences (NAS) in 1914, with its first issue published in 1915. The NAS itself had been founded in 1863, a private institution, but chartered by the U.S. Congress, with the goal to "investigate, examine, experiment, and report upon any subject of science or art." By 1914, the Academy was well established.

Prior to the start of the journal, NAS published three volumes of organizational transactions, consisting mostly of minutes of meetings and annual reports. In accordance with the guiding principles established by Astronomer George Ellery Hale, the foreign secretary of NAS in 1914, PNAS publishes brief first announcements of Academy members' and foreign associates' more important contributions to research and of work that appears to a member to be of particular importance.

The first managing editor of the journal was mathematician Edwin Bidwell Wilson.

Peer review
All research papers published in PNAS are peer-reviewed. The standard mode is for papers to be submitted directly to PNAS rather than going through an Academy member. Members may handle the peer review process for up to 4 of their own papers per year--this is an open review process because the member selects and communicates directly with the referees. These submissions and reviews, like all for PNAS, are evaluated for publication by the PNAS Editorial Board. Members may also communicate up to 2 papers from non-members to PNAS each year. This is an anonymous review process in that the identities of the referees are not revealed to the authors. Referees are selected by the NAS member.

Dual use papers and national security
In 2003, PNAS issued an editorial stating its policy on publication of sensitive material in the life sciences. PNAS stated that it would "continue to monitor submitted papers for material that may be deemed inappropriate and that could, if published, compromise the public welfare." This statement was in keeping with the efforts of several other journals. In 2005 PNAS published an article titled "Analyzing a bioterror attack on the food supply: The case of botulinum toxin in milk" despite objections raised by the U.S. Department of Health and Human Services. The paper was published with a commentary by the president of the Academy at the time, Bruce Alberts, titled "Modeling attacks on the food supply".

Impact
PNAS is widely read by researchers, particularly those involved in basic sciences, around the world. PNAS Online receives 11.6 million hits per month. The journal is notable for its policy of making research articles freely available online to everyone 6 months after publication (delayed open access), or immediately if authors have chosen the "open access" option (hybrid open access). Immediately free online access (without the 6-month delay) is provided for more than 140 developing countries and for some categories of papers such as colloquia. Abstracts, tables of contents, and online supporting information are free. Anyone can sign up to receive free tables of contents by email.

Because PNAS is self-sustaining and receives no direct funding from the government or the National Academy of Sciences, the journal charges authors publication fees and subscription fees to offset the cost of the editorial and publication process. The journal's impact factor for 2004 was 10.452, for 2005 was 10.231, and 2006 was 9.643 (as measured by Thomson ISI). PNAS is the second most cited scientific journal with 1,338,191 citations from 1994–2004 (the Journal of Biological Chemistry is the most cited journal over this period with 1,740,902 citations in total).