Placenta

PLACENTA invites submission of full-length papers and short communications of high quality research that provide novel insight into any aspect of placental biology. Technical notes are welcome if a new technique or methodology is described that clarifies or expands experimental studies. Case reports are acceptable if they illustrate a key point about placental biology, yet should not include an extensive literature review. Book reviews and letters to the Editors are selectively published. Letters to the Editors may comment on any issue important to placentology, including comments about articles published in PLACENTA or may communicate isolated findings that do not justify publication as a short communication. Reviews (Current Topics) and topic overviews (Current Opinion) are usually solicited by the Editors.

PLACENTA covers all aspects of the human and animal placenta including evolution, development, histology, physiology, metabolism, endocrinology, microbiology, pathology, immunology, pharmacology, cell biology, biochemistry, and molecular mechanisms underlying placental function. We welcome articles describing clinical aspects of placental structure or function and studies of implantation, comparative placentation, fetoplacental interactions, trophoblastic neoplasia and placental vascular biology. Authors should justify use of cell lines as models for trophoblast function.

All manuscripts should be written in English and each will be evaluated in a similar manner, irrespective of country of origin. Neither the journal, nor the publisher will assume any responsibility for statements in the articles, which are the sole responsibility of the authors.

Unless requested otherwise, manuscripts from Europe and Africa will be handled by Graham Burton (Cambridge, UK), manuscripts from North and Central America and Canada will be handled by Yoel Sadovsky (Pittsburgh, USA) and those from Australasia, Asia, India, Middle East and South America by Vicky Clifton (Adelaide, Australia).

Types of papers

Original articles: a full-length report of original basic or clinical investigation that provides novel insight and places the findings in a mechanistic, functional, or evolutionary context (2000-3000 words, up to 45 references, and up to 6 tables and/or figures). A structured abstract of no more than 250 words with the following sections (objectives, study design, main outcome measures, results, conclusions) is required. The rest of the paper should be structured as follows: Introduction, Methods, Results, Discussion, References.

NOTE
Original (full length) articles must be between 2000-3000 words (includes the abstract, introduction, methods, results and discussion), excluding up to forty-five (45) references

Short communications/Technical notes: descriptive studies or methodological advances must not exceed 1,000 words with no more than two (2) tables or illustrations and twenty-five (25) references. An unstructured abstract of no more than 100 words is required. The text should also be structured in four parts: Introduction, Methods, Results and Discussion, but the Results and Discussion sections may be combined.

Abstract, Introduction, Methods, Results and Discussion must NOT exceed 1,000 words and is excluding twenty-five (25) number of references."

Review articles: a comprehensive review of prior publications relating to an important clinical subject (2000-3000 words and 30-50 references). An unstructured abstract of no more than 250 words is required. The Introduction should indicate why the topic is important and should state the specific objective(s) of the review. The Conclusion should include the clinical implications and observations regarding the need for additional research. Systematic reviews should follow the PRISMA guidelines. Meta-analysis of observational studies should follow the MOOSE guidelines.
Further information can be obtained from the EQUATOR web site: http://www.equator-network.org/resource-centre/library-of-health-research-reporting/reporting-guidelines.

Case reports: must not exceed 1,000 words and ten (10) references and two (2) tables and/or figures.

Letters to the Editor: a question or challenge to an article published recently in the journal. Letters must be received within 6 weeks of publication of the article to which they refer and should be no longer than 250 words with up to 7 references and 1 figure and/or table.

NOTE
Placenta will not charge authors for pages for publication of articles.

Contact details for submission

Submission of manuscripts proceeds entirely online at http://ees.elsevier.com/plac



Ethics in publishing

For information on Ethics in publishing and Ethical guidelines for journal publication see http://www.elsevier.com/publishingethics and http://www.elsevier.com/ethicalguidelines.

Policy and ethics

The work described in your article must have been carried out in accordance with The Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments involving humans http://www.wma.net/en/30publications/10policies/b3/index.html; EU Directive 2010/63/EU for animal experiments http://ec.europa.eu/environment/chemicals/lab_animals/legislation_en.htm; Uniform Requirements for manuscripts submitted to Biomedical journals http://www.icmje.org. This must be stated at an appropriate point in the article.

Conflict of interest

All authors are requested to disclose any actual or potential conflict of interest including any financial, personal or other relationships with other people or organizations within three years of beginning the submitted work that could inappropriately influence, or be perceived to influence, their work. See also http://www.elsevier.com/conflictsofinterest.

Submission declaration

Submission of an article implies that the work described has not been published previously (except in the form of an abstract or as part of a published lecture or academic thesis), that it is not under consideration for publication elsewhere, that its publication is approved by all authors and tacitly or explicitly by the responsible authorities where the work was carried out, and that, if accepted, it will not be published elsewhere including electronically in the same form, in English or in any other language, without the written consent of the copyright-holder.

Contributors

Submission of multi-authored manuscripts to this journal requires the consent of each author and all have to sign the covering letter. All authors of, and all contributors (including medical writers and editors) must specify their individual contributions at the end of the text. The following format is suggested: 'I declare that I participated in the (here list contributions made to the study) and that I have seen and approved the final version. I have the following conflicts of interest' (list here all relevant conflicts and source of funding). This should be listed in the 'Comments' field in EES.

Changes to authorship

This policy concerns the addition, deletion, or rearrangement of author names in the authorship of accepted manuscripts:
Before the accepted manuscript is published in an online issue: Requests to add or remove an author, or to rearrange the author names, must be sent to the Journal Manager from the corresponding author of the accepted manuscript and must include: (a) the reason the name should be added or removed, or the author names rearranged and (b) written confirmation (e-mail, fax, letter) from all authors that they agree with the addition, removal or rearrangement. In the case of addition or removal of authors, this includes confirmation from the author being added or removed. Requests that are not sent by the corresponding author will be forwarded by the Journal Manager to the corresponding author, who must follow the procedure as described above. Note that: (1) Journal Managers will inform the Journal Editors of any such requests and (2) publication of the accepted manuscript in an online issue is suspended until authorship has been agreed.
After the accepted manuscript is published in an online issue: Any requests to add, delete, or rearrange author names in an article published in an online issue will follow the same policies as noted above and result in a corrigendum.

Copyright

Upon acceptance of an article, authors will be asked to complete a 'Journal Publishing Agreement' (for more information on this and copyright see http://www.elsevier.com/copyright). Acceptance of the agreement will ensure the widest possible dissemination of information. An e-mail will be sent to the corresponding author confirming receipt of the manuscript together with a 'Journal Publishing Agreement' form or a link to the online version of this agreement.
Subscribers may reproduce tables of contents or prepare lists of articles including abstracts for internal circulation within their institutions. Permission of the Publisher is required for resale or distribution outside the institution and for all other derivative works, including compilations and translations (please consult http://www.elsevier.com/permissions). If excerpts from other copyrighted works are included, the author(s) must obtain written permission from the copyright owners and credit the source(s) in the article. Elsevier has preprinted forms for use by authors in these cases: please consult http://www.elsevier.com/permissions.

Retained author rights

As an author you (or your employer or institution) retain certain rights; for details you are referred to: http://www.elsevier.com/authorsrights.

Role of the funding source

You are requested to identify who provided financial support for the conduct of the research and/or preparation of the article and to briefly describe the role of the sponsor(s), if any, in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. If the funding source(s) had no such involvement then this should be stated. Please see http://www.elsevier.com/funding.

Funding body agreements and policies

Elsevier has established agreements and developed policies to allow authors whose articles appear in journals published by Elsevier, to comply with potential manuscript archiving requirements as specified as conditions of their grant awards. To learn more about existing agreements and policies please visit http://www.elsevier.com/fundingbodies.

Language and language services

Please write your text in good English (American or British usage is accepted, but not a mixture of these). Authors who require information about language editing and copyediting services pre- and post-submission please visit http://webshop.elsevier.com/languageservices or our customer support site at http://support.elsevier.com for more information.

Patient details

Unless you have written permission from the patient (or, where applicable, the next of kin), the personal details of any patient included in any part of the article and in any supplementary materials (including all illustrations and videos) must be removed before submission. For further information see http://www.elsevier.com/patientphotographs.

Submission

Submission to this journal proceeds totally online. Use the following guidelines to prepare your article. Via the homepage of this journal, http://ees.elsevier.com/plac, you will be guided stepwise through the creation and uploading of the various files. The system automatically converts source files to a single PDF file of the article, which is used in the peer-review process. Please note that even though manuscript source files are converted to PDF files at submission for the review process, these source files are needed for further processing after acceptance. All correspondence, including notification of the Editors' decision and requests for revision, takes place by e-mail removing the need for a paper trail.

Referees

To expedite the review process Authors are required to provide the editorial office with the names and email addresses of up to 5 potential Referees that are able to competently review the article submitted for possible publication. The Referees are not to be associated with or involved with the article in any way or be from the same institution as the Author(s) involved with the article.



Use of wordprocessing software

It is important that the file be saved in the native format of the wordprocessor used. The text should be in single-column format. Keep the layout of the text as simple as possible. Most formatting codes will be removed and replaced on processing the article. In particular, do not use the wordprocessor's options to justify text or to hyphenate words. However, do use bold face, italics, subscripts, superscripts etc. When preparing tables, if you are using a table grid, use only one grid for each individual table and not a grid for each row. If no grid is used, use tabs, not spaces, to align columns. The electronic text should be prepared in a way very similar to that of conventional manuscripts (see also the Guide to Publishing with Elsevier: http://www.elsevier.com/guidepublication). Note that source files of figures, tables and text graphics will be required whether or not you embed your figures in the text. See also the section on Electronic artwork.
To avoid unnecessary errors you are strongly advised to use the 'spell-check' and 'grammar-check' functions of your wordprocessor.

LaTeX

If the LaTeX file is suitable, proofs will be produced without rekeying the text. The article should preferably be written using Elsevier's document class 'elsarticle', or alternatively any of the other recognized classes and formats supported in Elsevier's electronic submissions system, for further information see http://www.elsevier.com/wps/find/authorsview.authors/latex-ees-supported.
The Elsevier 'elsarticle' LaTeX style file package (including detailed instructions for LaTeX preparation) can be obtained from the Quickguide: http://www.elsevier.com/latex. It consists of the file: elsarticle.cls, complete user documentation for the class file, bibliographic style files in various styles, and template files for a quick start.

Article structure

Introduction
The Introduction should describe the question addressed by the report, the relevant background and must state the objective of the research. The literature review should be relevant but not detailed.

Materials and methods
The Methods section should describe the research methodology in sufficient detail that others could reasonably be expected to be able to duplicate the work. However, if the methodology has been previously published, the appropriate reference should be cited, and a full description is not required. The sequences of oligonucleotides, if not previously published, should be provided. Novel DNA or protein sequences should be deposited in an appropriate database (eg, Genbank, EMBL, SWISS-PROT), with the accession numbers included in the manuscript (see below). Provide suppliers' names for all antibodies used. Methods of statistical analysis should be identified and, when appropriate, the basis for their selection stated. Statistical software programs used should be cited in the text. P values should be expressed to no more than three decimal places. Reports in which statistical difference is lacking must provide some indication of the study's power to detect such differences, and this information must be included in the abstract.

Results
The Results section should present the findings in appropriate detail. Tables and figures may be used, but duplication between text and tables or figures is to be avoided.

Discussion
The Discussion section should be used to critically appraise the implications of the findings and to compare them with those of other studies. Repetition of the results section should be avoided.

Conclusions
The main conclusions of the study may be presented in a short Conclusions section, which may stand alone or form a subsection of a Discussion or Results and Discussion section.

Essential title page information

• Title. Concise and informative. Titles are often used in information-retrieval systems. Avoid abbreviations and formulae where possible.
• Author names and affiliations. Where the family name may be ambiguous (e.g., a double name), please indicate this clearly. Present the authors' affiliation addresses (where the actual work was done) below the names. Indicate all affiliations with a lower-case superscript letter immediately after the author's name and in front of the appropriate address. Provide the full postal address of each affiliation, including the country name and, if available, the e-mail address of each author.
• Corresponding author. Clearly indicate who will handle correspondence at all stages of refereeing and publication, also post-publication. Ensure that telephone and fax numbers (with country and area code) are provided in addition to the e-mail address and the complete postal address. Contact details must be kept up to date by the corresponding author.
• Present/permanent address. If an author has moved since the work described in the article was done, or was visiting at the time, a 'Present address' (or 'Permanent address') may be indicated as a footnote to that author's name. The address at which the author actually did the work must be retained as the main, affiliation address. Superscript Arabic numerals are used for such footnotes.

Abstract

A concise and factual abstract is required. The abstract should state briefly the purpose of the research, the principal results and major conclusions. An abstract is often presented separately from the article, so it must be able to stand alone. For this reason, References should be avoided, but if essential, then cite the author(s) and year(s). Also, non-standard or uncommon abbreviations should be avoided, but if essential they must be defined at their first mention in the abstract itself.

Keywords

Immediately after the abstract, provide a maximum of 6 keywords, using American spelling and avoiding general and plural terms and multiple concepts (avoid, for example, 'and', 'of'). Be sparing with abbreviations: only abbreviations firmly established in the field may be eligible. These keywords will be used for indexing purposes.

Abbreviations

Define abbreviations that are not standard in this field in a footnote to be placed on the first page of the article. Such abbreviations that are unavoidable in the abstract must be defined at their first mention there, as well as in the footnote. Ensure consistency of abbreviations throughout the article.

Acknowledgements

Collate acknowledgements in a separate section at the end of the article before the references and do not, therefore, include them on the title page, as a footnote to the title or otherwise. List here those individuals who provided help during the research (e.g., providing language help, writing assistance or proof reading the article, etc.).

Nomenclature and units

Authors should adhere to the internationally accepted convention for the naming of proteins and genes. For the human, gene symbols should be italicised, with all letters in uppercase (e.g., EGF for epidermal growth factor). Protein designations are the same as the gene symbol, but are not italicised; all letters are in uppercase (EGF). mRNAs and cDNAs use the same formatting conventions as the gene symbol. The same principles apply for the mouse, except that only the first letter should be in uppercase (Egf and Egf). For full details and other species refer to http://en.wikipedia.org/wiki/Gene_nomenclature.

Follow internationally accepted rules and conventions: use the international system of units (SI). If other quantities are mentioned, give their equivalent in SI. You are urged to consult IUB: Biochemical Nomenclature and Related Documents: http://www.chem.qmw.ac.uk/iubmb/ for further information.

Database linking

Elsevier aims at connecting online articles with external databases which are useful in their respective research communities. If your article contains relevant unique identifiers or accession numbers (bioinformatics) linking to information on entities (genes, proteins, diseases, etc.) or structures deposited in public databases, then please indicate those entities according to the standard explained below.
Authors should explicitly mention the database abbreviation (as mentioned below) together with the actual database number, bearing in mind that an error in a letter or number can result in a dead link in the online version of the article.
Please use the following format: Database ID: xxxx
Links can be provided in your online article to the following databases (examples of citations are given in parentheses):
• ASTM: ASTM Standards Database (ASTM ID: G63)
• CCDC: Cambridge Crystallographic Data Centre (CCDC ID: AI631510)
• GenBank: Genetic sequence database at the National Center for Biotechnology Information (NCBI) (GenBank ID: BA123456)
• GEO: Gene Expression Omnibus (GEO ID: GSE27196; GEO ID: GPL5366; GEO ID: GSM9853)
• MI: EMBL-EBI OLS Molecular Interaction Ontology (MI ID: 0218)
• MINT: Molecular INTeractions database (MINT ID: 6166710)
• NCBI Taxonomy: NCBI Taxonomy Browser (NCBI Taxonomy ID: 48184)
• NCT: ClinicalTrials.gov (NCT ID: NCT00222573)
• OMIM: Online Mendelian Inheritance in Man (OMIM ID: 601240)
• PDB: Worldwide Protein Data Bank (PDB ID: 1TUP)
• TAIR: The Arabidopsis Information Resource database (TAIR ID: AT1G01020)
• UniProt: Universal Protein Resource Knowledgebase (UniProt ID: Q9H0H5)

Footnotes

Footnotes should be used sparingly. Number them consecutively throughout the article, using superscript Arabic numbers. Many wordprocessors build footnotes into the text, and this feature may be used. Should this not be the case, indicate the position of footnotes in the text and present the footnotes themselves separately at the end of the article. Do not include footnotes in the Reference list.
Table footnotes
Indicate each footnote in a table with a superscript lowercase letter.

Artwork

Electronic artwork
General points
• Make sure you use uniform lettering and sizing of your original artwork.
• Save text in illustrations as 'graphics' or enclose the font.
• Only use the following fonts in your illustrations: Arial, Courier, Times, Symbol.
• Number the illustrations according to their sequence in the text.
• Use a logical naming convention for your artwork files.
• Provide captions to illustrations separately.
• Produce images near to the desired size of the printed version.
• Submit each figure as a separate file.

A detailed guide on electronic artwork is available on our website:
http://www.elsevier.com/artworkinstructions
You are urged to visit this site; some excerpts from the detailed information are given here.
Formats
Regardless of the application used, when your electronic artwork is finalised, please 'save as' or convert the images to one of the following formats (note the resolution requirements for line drawings, halftones, and line/halftone combinations given below):
EPS: Vector drawings. Embed the font or save the text as 'graphics'.
TIFF: Color or grayscale photographs (halftones): always use a minimum of 300 dpi.
TIFF: Bitmapped line drawings: use a minimum of 1000 dpi.
TIFF: Combinations bitmapped line/half-tone (color or grayscale): a minimum of 500 dpi is required.
If your electronic artwork is created in a Microsoft Office application (Word, PowerPoint, Excel) then please supply 'as is'.
Please do not:
• Supply files that are optimised for screen use (e.g., GIF, BMP, PICT, WPG); the resolution is too low;
• Supply files that are too low in resolution;
• Submit graphics that are disproportionately large for the content.

Color artwork
Please make sure that artwork files are in an acceptable format (TIFF, EPS or MS Office files) and with the correct resolution. If, together with your accepted article, you submit usable color figures then Elsevier will ensure, at no additional charge, that these figures will appear in color on the Web (e.g., ScienceDirect and other sites) regardless of whether or not these illustrations are reproduced in color in the printed version. For color reproduction in print, you will receive information regarding the costs from Elsevier after receipt of your accepted article. Please indicate your preference for color: in print or on the Web only. For further information on the preparation of electronic artwork, please see http://www.elsevier.com/artworkinstructions.
Please note: Because of technical complications which can arise by converting color figures to 'gray scale' (for the printed version should you not opt for color in print) please submit in addition usable black and white versions of all the color illustrations.

Figure captions
Ensure that each illustration has a caption. Supply captions separately, not attached to the figure. A caption should comprise a brief title (not on the figure itself) and a description of the illustration. Keep text in the illustrations themselves to a minimum but explain all symbols and abbreviations used.

Tables

Number tables consecutively in accordance with their appearance in the text. Place footnotes to tables below the table body and indicate them with superscript lowercase letters. Avoid vertical rules. Be sparing in the use of tables and ensure that the data presented in tables do not duplicate results described elsewhere in the article.

Table(s) for studies of human placenta

Authors submitting manuscripts about human placentas are strongly encouraged, but not required, to complete Table 1: Clinical characteristics of pregnancies for placentas studied, available as a download here: Guide for authors Table 1. In the Methods section of the author's manuscript, please cite the source for this Table as: Nelson DM, Burton GJ, A technical note to improve the reporting of studies of the human placenta, Placenta (2010), doi:10.1016/j.placenta.2010.12.008 and complete the clinical data listed in the downloaded Table. Table 1 should then appear immediately after the references in the author's submitted manuscript so that reviewers will have easy access to the data contained. Multiple tables can be included in studies when patients from different clinical groups are studied, e.g. controls, preeclampsia, diabetes mellitus, etc. Editors will assure that authors will not be penalized for multiple entries of "unknown" into the Table, both by instructions to reviewers and by evaluation of the content of reviews. The reference citation above and the Table(s) reporting clinical characteristics are not included in the tally of Figures and Tables for the manuscript as a whole. If the author's manuscript is accepted for publication in Placenta, the Table will be cited in a footnote to direct readers to Supplementary Data where the Table 1 will appear for viewing. Again, the Table will not count in the page allocation of the author's manuscript.

References

Authors are responsible for the accuracy of references. The 'Vancouver' style is used. References appearing for the first time in a table or figure should be cited in the text where the table or figure is mentioned. References cited must have been published in peer-reviewed publications.

Citation in text
Please ensure that every reference cited in the text is also present in the reference list (and vice versa). Any references cited in the abstract must be given in full. Unpublished results and personal communications are not recommended in the reference list, but may be mentioned in the text. If these references are included in the reference list they should follow the standard reference style of the journal and should include a substitution of the publication date with either 'Unpublished results' or 'Personal communication'. Citation of a reference as 'in press' implies that the item has been accepted for publication.

Web references
As a minimum, the full URL should be given and the date when the reference was last accessed. Any further information, if known (DOI, author names, dates, reference to a source publication, etc.), should also be given. Web references can be listed separately (e.g., after the reference list) under a different heading if desired, or can be included in the reference list.

Reference style
Text: Indicate references by number(s) in square brackets in line with the text. The actual authors can be referred to, but the reference number(s) must always be given.
List: Number the references (numbers in square brackets) in the list in the order in which they appear in the text.
Examples:
Reference to a journal publication:
[1] Van der Geer J, Hanraads JAJ, Lupton RA. The art of writing a scientific article. J Sci Commun 2010;163:51–9.
Reference to a book:
[2] Strunk Jr W, White EB. The elements of style. 4th ed. New York: Longman; 2000.
Reference to a chapter in an edited book:
[3] Mettam GR, Adams LB. How to prepare an electronic version of your article. In: Jones BS, Smith RZ, editors. Introduction to the electronic age, New York: E-Publishing Inc; 2009, p. 281–304.
Note shortened form for last page number. e.g., 51–9, and that for more than 6 authors the first 6 should be listed followed by 'et al.' For further details you are referred to 'Uniform Requirements for Manuscripts submitted to Biomedical Journals' (J Am Med Assoc 1997;277:927–34) (see also http://www.nlm.nih.gov/bsd/uniform_requirements.html).

Journal abbreviations source
Journal names should be abbreviated according to
Index Medicus journal abbreviations: http://www.nlm.nih.gov/tsd/serials/lji.html;
List of title word abbreviations: http://www.issn.org/2-22661-LTWA-online.php;
CAS (Chemical Abstracts Service): http://www.cas.org/sent.html.

Video data

Elsevier accepts video material and animation sequences to support and enhance your scientific research. Authors who have video or animation files that they wish to submit with their article are strongly encouraged to include these within the body of the article. This can be done in the same way as a figure or table by referring to the video or animation content and noting in the body text where it should be placed. All submitted files should be properly labeled so that they directly relate to the video file's content. In order to ensure that your video or animation material is directly usable, please provide the files in one of our recommended file formats with a preferred maximum size of 50 MB. Video and animation files supplied will be published online in the electronic version of your article in Elsevier Web products, including ScienceDirect: http://www.sciencedirect.com. Please supply 'stills' with your files: you can choose any frame from the video or animation or make a separate image. These will be used instead of standard icons and will personalize the link to your video data. For more detailed instructions please visit our video instruction pages at http://www.elsevier.com/artworkinstructions. Note: since video and animation cannot be embedded in the print version of the journal, please provide text for both the electronic and the print version for the portions of the article that refer to this content.

Supplementary data

Elsevier accepts electronic supplementary material to support and enhance your scientific research. Supplementary files offer the author additional possibilities to publish supporting applications, high-resolution images, background datasets, sound clips and more. Supplementary files supplied will be published online alongside the electronic version of your article in Elsevier Web products, including ScienceDirect: http://www.sciencedirect.com. In order to ensure that your submitted material is directly usable, please provide the data in one of our recommended file formats. Authors should submit the material in electronic format together with the article and supply a concise and descriptive caption for each file. For more detailed instructions please visit our artwork instruction pages at http://www.elsevier.com/artworkinstructions.

Submission checklist

The following list will be useful during the final checking of an article prior to sending it to the journal for review. Please consult this Guide for Authors for further details of any item.
Ensure that the following items are present:
One author has been designated as the corresponding author with contact details:
• E-mail address
• Full postal address
• Telephone and fax numbers
All necessary files have been uploaded, and contain:
• Keywords
• All figure captions
• All tables (including title, description, footnotes)
Further considerations
• Manuscript has been 'spell-checked' and 'grammar-checked'
• References are in the correct format for this journal
• All references mentioned in the Reference list are cited in the text, and vice versa
• Permission has been obtained for use of copyrighted material from other sources (including the Web)
• Color figures are clearly marked as being intended for color reproduction on the Web (free of charge) and in print, or to be reproduced in color on the Web (free of charge) and in black-and-white in print
• If only color on the Web is required, black-and-white versions of the figures are also supplied for printing purposes
For any further information please visit our customer support site at http://support.elsevier.com.



Use of the Digital Object Identifier

The Digital Object Identifier (DOI) may be used to cite and link to electronic documents. The DOI consists of a unique alpha-numeric character string which is assigned to a document by the publisher upon the initial electronic publication. The assigned DOI never changes. Therefore, it is an ideal medium for citing a document, particularly 'Articles in press' because they have not yet received their full bibliographic information. The correct format for citing a DOI is shown as follows (example taken from a document in the journal Physics Letters B):
doi:10.1016/j.physletb.2010.09.059
When you use the DOI to create URL hyperlinks to documents on the web, the DOIs are guaranteed never to change.

Proofs

One set of page proofs (as PDF files) will be sent by e-mail to the corresponding author (if we do not have an e-mail address then paper proofs will be sent by post) or, a link will be provided in the e-mail so that authors can download the files themselves. Elsevier now provides authors with PDF proofs which can be annotated; for this you will need to download Adobe Reader version 7 (or higher) available free from http://get.adobe.com/reader. Instructions on how to annotate PDF files will accompany the proofs (also given online). The exact system requirements are given at the Adobe site: http://www.adobe.com/products/reader/tech-specs.html.
If you do not wish to use the PDF annotations function, you may list the corrections (including replies to the Query Form) and return them to Elsevier in an e-mail. Please list your corrections quoting line number. If, for any reason, this is not possible, then mark the corrections and any other comments (including replies to the Query Form) on a printout of your proof and return by fax, or scan the pages and e-mail, or by post. Please use this proof only for checking the typesetting, editing, completeness and correctness of the text, tables and figures. Significant changes to the article as accepted for publication will only be considered at this stage with permission from the Editor. We will do everything possible to get your article published quickly and accurately – please let us have all your corrections within 48 hours. It is important to ensure that all corrections are sent back to us in one communication: please check carefully before replying, as inclusion of any subsequent corrections cannot be guaranteed. Proofreading is solely your responsibility. Note that Elsevier may proceed with the publication of your article if no response is received.

Offprints

The corresponding author, at no cost, will be provided with a PDF file of the article via e-mail. For an extra charge, paper offprints can be ordered via the offprint order form which is sent once the article is accepted for publication. The PDF file is a watermarked version of the published article and includes a cover sheet with the journal cover image and a disclaimer outlining the terms and conditions of use.



For inquiries relating to the submission of articles (including electronic submission) please visit this journal's homepage. Contact details for questions arising after acceptance of an article, especially those relating to proofs, will be provided by the publisher. You can track accepted articles at http://www.elsevier.com/trackarticle. You can also check our Author FAQs (http://www.elsevier.com/authorFAQ) and/or contact Customer Support via http://support.elsevier.com.

Author Information Pack