About AOP
All monthly Nature Clinical Practice Journals offer Advance Online Publication (AOP) Practice Points on their websites.
Each journal's website includes an AOP table of contents, in which Practice Points are listed in order of publication date (beginning with the most recent). Each article carries a digital object identifier (doi), which serves as a unique electronic identification tag for that article. As soon as the monthly issue is printed, articles will be removed from the AOP table of contents, assigned a page number and transferred to that issue's table of contents on the website. The doi remains attached to the article to provide a persistent identifier.
We believe that rapid online publication is a valuable service to readers, and we encourage you to visit our sites often.
Top of pageFrequently asked questions
Q. How often are new articles published AOP?
A. New Practice Points are uploaded to the AOP section of our website once per week.
Q. Can the AOP version of the article be considered definitive?
A. Yes. Different publishers have different policies, and some journals choose to publish unedited versions of articles on their websites. Our policy, however, is to publish only the final edited version of the article. The article is thus complete in every respect except that instead of having a volume/issue/page number as an identifier, it has a doi.
Q. What is a digital object identifier?
A. A digital object identifier (doi) is an identifier string (combination of numbers and letters) that can be assigned to an item of editorial content and that provides a unique identifier for that item. The doi system is administered by the International doi Foundation, a not-for-profit organization, with the aim of providing a common format for cross-linking of electronic content from different publishers. The doi search system for the doi is maintained by CrossRef, a not-for-profit organization whose aim is to enable the ongoing usage of doi as a reference linking standard. Nature Publishing Group is a founding member and board member of CrossRef.
Q. What do the numbers in the doi signify?
A. The doi has two components, a prefix (before the slash) and a suffix (after the slash). The prefix is composed of a server identifier (10) and a unique identifier assigned to a particular publisher — for example, the identifier for the Nature Publishing Group is 1038. Therefore the entire doi prefix for an article published by the Nature Publishing Group is 10.1038. The suffix is an arbitrary number provided by the publisher. It can be composed of numbers and/or letters. It does not necessarily have any systematic significance — for instance, it does not automatically indicate the page number or the date of publication. Each doi is registered in a central resolution database that associates it with one or more corresponding web locations (URLs). For example, the doi 10.1038/ncponc0024 connects to http://dx.doi.org/10.1038/ncponc0024.
Q. What is CrossRef?
A. CrossRef is a not-for-profit organization that develops and maintains a system to assist in the linking of published papers based on their dois.
Q. How can I use a doi to find a paper?
A. There are two ways to use a doi to find a paper:
1. dois from other articles can be embedded into the linking coding of an article's reference section. In Nature Clinical Practice journals these appear as "|Article|" in the reference section of the online journal. When |Article| is clicked it opens another browser window and takes you to the entrance page (often the abstract) for that article. Depending on the source of the article, this page can be on the Nature Publishing Group site or a site of another publisher. This service is enabled by CrossRef.
2. If you know a doi, you can insert it directly into your browser's location bar as follows. For the DOI 10.1038/ncponc0024, you would have to type http://dx.doi.org/10.1038/ncponc0024. This will bring you to the entrance page of the desired article.
Q. Does Medline use dois?
A. Medline currently captures dois along with online publication dates in its records and is working on enhancing its level of support for the doi system.
Q. Does The Institute for Scientific Information (the 'Impact factor people') use dois?
A. The Institute for Scientific Information (ISI) currently captures dois in their records. However, the doi is recorded at the same time as the volume/issue/page number. Therefore, it is not using the doi to capture information prior to print publication, but rather recording it simply as an additional piece of information to complete its records.
Q. What is the 'official' publication date?
A. Many journals, and most abstracting and indexing services (including Medline and Institute for Scientific Information), still cite the print date as the publication date. This is an evolving standard, however, and the trend now is for publishers to state both the 'Online Publication Date' and the 'Print Publication Date'. Nature Publishing Group will continue to publish both dates for our own papers, and we hope that the scientific communities and abstracting and indexing services will recognize these dates.
For legal purposes (for example, establishing intellectual property rights), it is our assumption that online publication will constitute public disclosure. This is, however, for the courts to decide; our role as a publisher is to provide clear documentation of the publication history, online and in print.
Q. What determines the order in which AOP papers are listed on the website?
A. AOP material is listed in order of online publication date, most recent first. The order of AOP listing does not necessarily correspond to the order of subsequent print publication.
Q. How do I cite a paper that is an AOP but is not in print?
A. One advantage of the doi system is that papers can be cited using a doi only, before final pagination and print publication. The doiI is a persistent identifier, which remains with the article even after it is published in print. We recommend citing dois as follows: At the end of the reference citation, type the complete doi (for example, doi: 10.1038/ncponc0024).
Q. How does AOP affect the calculation of impact factors?
A. Impact factors are calculated by ISI. At present, ISI bases its calculations on the date of print publication alone. It is possible that the ISI will choose to change this policy in the future, but under the present system, AOP has no effect on impact factor calculations.
For a full explanation of how impact factors are calculated, see: http://www.isinet.com/essays/journalcitationreports/7.html
Q. Must I subscribe to the journal in order to read AOP articles?
A. Yes. Access to the full-text article requires a paid subscription or a site license.
