A&A Author Guide: Crafting Stellar Scientific Papers

1. Understanding the A&A Author Guide

The A&A author guide serves as a comprehensive resource for authors preparing manuscripts for submission to Astronomy & Astrophysics (A&A), a leading international journal in the field. This guide aims to facilitate the creation of high-quality, clear, and concise scientific papers that adhere to the journal’s established standards. By providing detailed instructions and recommendations on various aspects of writing, including grammar, style, and formatting, the A&A author guide helps authors ensure that their work is presented in a professional and accessible manner. The ultimate goal is to promote effective communication of scientific findings and contribute to the advancement of knowledge in astronomy and astrophysics. Access more resources at CONDUCT.EDU.VN to elevate your authoring skills and gain confidence in producing outstanding manuscripts.

1.1 Purpose of the A&A Author Guide

The primary purpose of the A&A author guide is to assist authors in preparing their manuscripts in accordance with the standards and expectations of the Astronomy & Astrophysics journal. It serves as a comprehensive reference tool, providing clear and concise guidelines on various aspects of scientific writing, including grammar, style, formatting, and referencing. By following the recommendations outlined in the guide, authors can ensure that their papers are well-written, easily understood, and consistent with the established conventions of the journal. This not only enhances the readability and impact of their work but also streamlines the review and publication process. For more information, contact us at 100 Ethics Plaza, Guideline City, CA 90210, United States. Whatsapp: +1 (707) 555-1234. Visit our website: CONDUCT.EDU.VN.

1.2 Scope of the Guide: What It Covers

The A&A author guide covers a wide range of topics relevant to scientific writing and manuscript preparation. These topics include, but are not limited to, the following:

• Grammar and style: The guide provides recommendations on grammar, punctuation, sentence structure, and word choice to ensure clarity and accuracy in writing.
• Formatting: It outlines the specific formatting requirements for A&A manuscripts, including font size, line spacing, margins, and heading styles.
• Figures and tables: The guide offers guidance on how to create effective figures and tables that present data clearly and concisely.
• Equations and mathematical expressions: It provides instructions on how to format equations and mathematical expressions to ensure readability and consistency.
• References: The guide explains how to properly cite sources and create a reference list that adheres to A&A’s citation style.
• Abbreviations and acronyms: It offers recommendations on the use of abbreviations and acronyms to avoid confusion and maintain consistency.
• Units and symbols: The guide provides a list of commonly used units and symbols in astronomy and astrophysics, along with guidelines on their proper usage.

1.3 Who Should Use This Guide?

The A&A author guide is intended for anyone who is preparing a manuscript for submission to Astronomy & Astrophysics. This includes:

• Researchers: The guide is an essential resource for researchers in astronomy and astrophysics who are writing up their findings for publication.
• Students: Students who are working on research projects or theses can use the guide to ensure that their writing meets the standards of the field.
• Language editors: Language editors can use the guide to ensure consistency in their editing and to help authors improve the clarity and accuracy of their writing.
• Anyone interested in scientific writing: The guide provides valuable insights into the principles of clear and effective scientific writing, which can be applied to other fields as well.

1.4 How to Navigate the Guide Effectively

To make the most of the A&A author guide, it is recommended to familiarize yourself with its structure and contents before you begin writing. The guide is typically organized into sections, each covering a specific aspect of scientific writing or manuscript preparation. You can use the table of contents or the index to quickly locate the information you need. In addition, the guide may include examples, tables, and figures to illustrate key concepts and recommendations. It is important to carefully read and understand these examples, as they can help you apply the guidelines correctly. Finally, if you have any questions or doubts, do not hesitate to consult with experienced colleagues or contact the A&A editorial office for clarification.

2. Key Principles of Clear and Concise Writing

Clear and concise writing is essential for effective communication in scientific papers. It ensures that readers can easily understand the author’s ideas and findings, without being distracted by unnecessary jargon, convoluted sentences, or ambiguous language. By adhering to the principles of clarity and concision, authors can enhance the readability and impact of their work, and increase the likelihood that it will be well-received by the scientific community. CONDUCT.EDU.VN provides additional guidance on writing with impact.

2.1 Avoiding Wordiness and Redundancy

Wordiness and redundancy are common pitfalls in scientific writing. They can make sentences longer and more complex than necessary, obscuring the author’s intended meaning and making it harder for readers to follow the argument. To avoid wordiness and redundancy, authors should:

• Use concise language: Choose the most direct and precise words to express your ideas.
• Eliminate unnecessary phrases: Cut out phrases that do not add substantive meaning to the sentence.
• Avoid repetition: Do not repeat the same idea or information multiple times in the same paragraph or section.
• Use active voice: Active voice is generally more concise and direct than passive voice.

Example:

• Wordy: “Due to the fact that the experiment was conducted under controlled conditions, we were able to obtain accurate results.”
• Concise: “Because the experiment was conducted under controlled conditions, we obtained accurate results.”

2.2 Using Precise and Specific Language

Precise and specific language is crucial for avoiding ambiguity and ensuring that readers understand the author’s intended meaning. To use precise and specific language, authors should:

• Choose words with clear meanings: Avoid using vague or ambiguous words that can be interpreted in multiple ways.
• Provide specific details: Include relevant details and examples to support your claims and make your writing more concrete.
• Define technical terms: Clearly define any technical terms or jargon that may be unfamiliar to readers.
• Use appropriate units and symbols: Use the correct units and symbols for all measurements and quantities.

Example:

• Vague: “The star was very bright.”
• Precise: “The star had an apparent magnitude of -2.0.”

2.3 Structuring Sentences for Maximum Clarity

The structure of sentences can have a significant impact on their clarity and readability. To structure sentences for maximum clarity, authors should:

• Keep sentences relatively short: Long sentences can be difficult to follow and understand. Aim for an average sentence length of 20-25 words.
• Use simple sentence structures: Avoid complex sentence structures with multiple clauses and subclauses.
• Place the main idea at the beginning of the sentence: This helps readers quickly grasp the central point of the sentence.
• Use parallel structure: When listing items or ideas, use parallel grammatical structures to create a sense of balance and coherence.

Example:

• Complex: “Although the data were noisy and the analysis was complicated, we were able to obtain statistically significant results, which suggests that our hypothesis is likely to be correct.”
• Simple: “Despite noisy data and complicated analysis, we obtained statistically significant results. These results support our hypothesis.”

2.4 Avoiding Jargon and Technical Terms When Possible

While jargon and technical terms are often necessary in scientific writing, they can also make papers difficult to understand for readers who are not experts in the field. To make your writing more accessible, you should:

• Use jargon and technical terms sparingly: Only use them when they are necessary to convey precise meaning.
• Define jargon and technical terms: When you do use them, clearly define them the first time they appear in the paper.
• Use plain language equivalents: When possible, use plain language equivalents for jargon and technical terms.
• Consider your audience: Keep in mind the background and knowledge level of your intended audience when deciding whether to use jargon and technical terms.

3. Mastering A&A Style Conventions

Adhering to the specific style conventions of Astronomy & Astrophysics is crucial for ensuring that your manuscript is consistent with the journal’s standards and expectations. These conventions cover a wide range of aspects, including grammar, punctuation, formatting, and referencing. By mastering these conventions, you can enhance the readability and professionalism of your work, and increase the likelihood that it will be favorably reviewed and accepted for publication. CONDUCT.EDU.VN offers detailed resources to help you master A&A style.

3.1 Spelling and Grammar: British vs. American English

A&A accepts both British and American English spellings and grammar. However, it is important to be consistent throughout your manuscript. Choose one style and stick to it. Here are some common differences between British and American English:

Feature	British English	American English
Spelling	colour, centre	color, center
Grammar	use of “shall”	less use of “shall”
Punctuation	use of single quotes	use of double quotes

3.2 Punctuation: Commas, Semicolons, and Colons

Proper punctuation is essential for clarity and readability. Here are some guidelines for using commas, semicolons, and colons in A&A manuscripts:

• Commas: Use commas to separate items in a list, to set off introductory phrases and clauses, and to separate independent clauses joined by a coordinating conjunction (e.g., and, but, or).
• Semicolons: Use semicolons to join two closely related independent clauses that are not joined by a coordinating conjunction, or to separate items in a list when those items already contain commas.
• Colons: Use colons to introduce a list, an explanation, or a quotation.

Examples:

• “The telescope observed three stars: Alpha Centauri, Beta Crucis, and Gamma Cygni.” (colon introducing a list)
• “The data were noisy; however, we were still able to obtain statistically significant results.” (semicolon joining two independent clauses)
• “We analyzed the data, and we found a significant correlation.” (comma separating independent clauses joined by a coordinating conjunction)

3.3 Capitalization and Abbreviations

Proper capitalization and abbreviation usage are important for maintaining consistency and professionalism in your manuscript. Here are some guidelines:

• Capitalization: Capitalize the first word of a sentence, proper nouns, and the first word of titles and headings.
• Abbreviations: Use abbreviations sparingly, and always define them the first time they appear in the paper. Use standard abbreviations whenever possible. Avoid using abbreviations in the abstract and introduction, unless they are very well-known.

Examples:

• “The Hubble Space Telescope (HST) has revolutionized our understanding of the universe.” (abbreviation defined)
• “We used the standard deviation (SD) to measure the spread of the data.” (abbreviation defined)

3.4 Numbers and Units

When writing about numbers and units, adhere to the following guidelines:

• Numbers: Spell out numbers one through nine, and use numerals for 10 and above. However, use numerals for all numbers when they are used with units of measurement.
• Units: Use SI units whenever possible. Always include a space between the number and the unit (e.g., 10 cm, not 10cm). Use negative exponents instead of slashes (e.g., m s-1, not m/s).

Examples:

• “We observed five planets.”
• “The star is located 10 parsecs away.”
• “The velocity of the gas is 300 km s-1.”

4. Avoiding Common Language Errors

Even experienced writers can make language errors, particularly when writing in a second language. Being aware of common errors and taking steps to avoid them can significantly improve the clarity and professionalism of your manuscript. CONDUCT.EDU.VN offers comprehensive language support resources.

4.1 Subject-Verb Agreement

Subject-verb agreement is a fundamental grammatical rule that requires the verb in a sentence to agree in number with its subject. Singular subjects take singular verbs, and plural subjects take plural verbs.

Examples:

• Incorrect: “The data shows a clear trend.”
• Correct: “The data show a clear trend.”
• Incorrect: “Each of the stars are bright.”
• Correct: “Each of the stars is bright.”

4.2 Incorrect Tense Usage

Using the correct tense is essential for conveying the correct meaning and avoiding confusion. In scientific writing, the past tense is typically used to describe completed actions or events, while the present tense is used to describe general truths or established facts.

Examples:

• Incorrect: “We will observe the star last night.”
• Correct: “We observed the star last night.”
• Incorrect: “The universe was expanding.”
• Correct: “The universe is expanding.”

4.3 Misplaced Modifiers

A misplaced modifier is a word, phrase, or clause that is placed in the wrong position in a sentence, making the sentence confusing or ambiguous. To avoid misplaced modifiers, make sure that modifiers are placed as close as possible to the words they modify.

Examples:

• Incorrect: “We observed the galaxy with a telescope that was very faint.”
• Correct: “We observed the very faint galaxy with a telescope.”
• Incorrect: “The star was studied by astronomers using a new technique extensively.”
• Correct: “The star was extensively studied by astronomers using a new technique.”

4.4 Confusing Words (e.g., Affect vs. Effect)

English has many pairs of words that are easily confused, such as “affect” and “effect,” “there,” “their,” and “they’re,” and “its” and “it’s.” To avoid using these words incorrectly, take the time to learn their meanings and usage.

• Affect vs. Effect: “Affect” is typically used as a verb, meaning “to influence,” while “effect” is typically used as a noun, meaning “a result.”
• There, Their, They’re: “There” indicates a place, “their” indicates possession, and “they’re” is a contraction of “they are.”
• Its vs. It’s: “Its” indicates possession, while “it’s” is a contraction of “it is.”

5. Understanding the Role of Language Editors

Language editors play a crucial role in ensuring the clarity, accuracy, and consistency of scientific papers. They are skilled professionals who are trained to identify and correct language errors, improve sentence structure, and ensure that the manuscript adheres to the journal’s style conventions. Understanding the role of language editors can help authors work more effectively with them and improve the overall quality of their manuscripts. CONDUCT.EDU.VN connects you with experienced language editors.

5.1 What Language Editors Do

Language editors perform a variety of tasks to improve the quality of scientific papers. These tasks may include:

• Correcting grammar and punctuation errors: Language editors carefully review manuscripts to identify and correct any grammar or punctuation errors.
• Improving sentence structure: They may rewrite sentences to make them clearer, more concise, and more grammatically correct.
• Ensuring consistency: Language editors ensure that the manuscript is consistent in terms of spelling, capitalization, abbreviation usage, and other style elements.
• Checking for accuracy: They may check the accuracy of facts, figures, and references.
• Providing feedback to authors: Language editors may provide feedback to authors on how to improve their writing.

5.2 What Language Editors Do Not Do

It is important to understand the limitations of language editors. They are not responsible for:

• Rewriting the entire paper: Language editors are not expected to rewrite the entire paper or to make substantial changes to the content.
• Conducting original research: They are not responsible for conducting original research or for verifying the accuracy of the scientific findings.
• Guaranteeing publication: Language editors cannot guarantee that a manuscript will be accepted for publication.

5.3 How to Respond to Language Editor Feedback

When you receive feedback from a language editor, it is important to carefully review their comments and suggestions. Consider each comment thoughtfully and make the necessary revisions to your manuscript. If you disagree with a comment, you can politely explain your reasoning to the language editor. However, it is generally best to defer to the language editor’s judgment, as they are experts in language and style.

5.4 The Value of Professional Editing Services

While the A&A author guide provides valuable guidance on scientific writing, it is not a substitute for professional editing services. If you are not a native English speaker or if you are unsure about the quality of your writing, it is highly recommended to hire a professional editor to review your manuscript. A professional editor can identify and correct errors that you may have missed, and can help you improve the clarity, accuracy, and overall quality of your paper.

6. Leveraging CONDUCT.EDU.VN Resources for Authors

CONDUCT.EDU.VN provides a wealth of resources designed to support authors in preparing high-quality scientific papers. These resources include detailed guides, templates, checklists, and links to other helpful websites. By leveraging these resources, authors can enhance their writing skills, improve the clarity and accuracy of their manuscripts, and increase their chances of publication success.

6.1 Accessing Writing Guides and Templates

CONDUCT.EDU.VN offers a variety of writing guides and templates that can help authors structure and format their manuscripts according to A&A standards. These resources cover topics such as:

• Abstract writing: How to write a clear and concise abstract that effectively summarizes the key findings of your paper.
• Introduction writing: How to write an engaging introduction that provides context for your research and clearly states your objectives.
• Methods writing: How to describe your methods in detail, ensuring that other researchers can reproduce your work.
• Results writing: How to present your results clearly and objectively, using tables and figures effectively.
• Discussion writing: How to interpret your results and discuss their implications in the context of previous research.
• Reference formatting: How to format your references according to A&A’s citation style.

6.2 Utilizing Checklists for Manuscript Preparation

CONDUCT.EDU.VN provides checklists that authors can use to ensure that they have addressed all the essential elements of manuscript preparation. These checklists cover topics such as:

• Grammar and spelling: Checking for grammar and spelling errors.
• Punctuation: Ensuring that punctuation is used correctly.
• Formatting: Verifying that the manuscript is formatted according to A&A standards.
• Figures and tables: Ensuring that figures and tables are clear, accurate, and properly labeled.
• References: Checking that all references are cited correctly and that the reference list is complete.

6.3 Connecting with Expert Support

CONDUCT.EDU.VN connects authors with expert support, including language editors, subject matter experts, and publishing consultants. These experts can provide valuable feedback on your manuscript and help you improve its clarity, accuracy, and overall quality.

6.4 Staying Updated on Publishing Best Practices

CONDUCT.EDU.VN keeps authors updated on the latest publishing best practices, including guidelines on ethical conduct, data management, and open access publishing. By staying informed about these issues, authors can ensure that they are meeting the highest standards of scientific integrity.

7. The Importance of Ethical Conduct in Publishing

Ethical conduct is paramount in scientific publishing. It ensures the integrity of research, promotes trust within the scientific community, and safeguards the reputation of both authors and journals. Adhering to ethical guidelines is not only a moral obligation but also a critical factor in the credibility and impact of your work. CONDUCT.EDU.VN emphasizes ethical publishing practices.

7.1 Avoiding Plagiarism and Self-Plagiarism

Plagiarism is the act of presenting someone else’s work as your own, without giving proper credit. Self-plagiarism is the act of republishing your own previously published work without proper attribution. Both plagiarism and self-plagiarism are considered serious ethical violations. To avoid plagiarism and self-plagiarism, you should:

• Always cite your sources: Give credit to the original authors of any ideas, data, or text that you use in your manuscript.
• Use quotation marks: Use quotation marks to indicate that you are quoting someone else’s words.
• Paraphrase carefully: When paraphrasing someone else’s ideas, make sure that you are expressing them in your own words and that you are still citing the original source.
• Obtain permission: If you are republishing your own previously published work, obtain permission from the copyright holder.

7.2 Ensuring Data Integrity and Reproducibility

Data integrity refers to the accuracy and reliability of your research data. Reproducibility refers to the ability of other researchers to replicate your findings using the same data and methods. To ensure data integrity and reproducibility, you should:

• Collect data carefully: Use appropriate methods to collect data and minimize errors.
• Document your methods: Clearly document your methods so that other researchers can reproduce your work.
• Store data securely: Store your data securely to prevent loss or damage.
• Share data openly: Share your data openly whenever possible, to promote transparency and reproducibility.

7.3 Declaring Conflicts of Interest

A conflict of interest is a situation in which your personal interests could potentially bias your research. Conflicts of interest can be financial, professional, or personal. To avoid conflicts of interest, you should:

• Disclose any potential conflicts of interest: Disclose any potential conflicts of interest to the journal editor.
• Recuse yourself from research: If you have a significant conflict of interest, you may need to recuse yourself from the research.

7.4 Following Authorship Guidelines

Authorship guidelines specify who should be listed as an author on a scientific paper. Generally, an author should have made a significant contribution to the research, including:

• Conceiving and designing the study: Developing the research question and designing the study.
• Collecting data: Collecting and analyzing data.
• Interpreting results: Interpreting the results of the study.
• Writing the manuscript: Writing and revising the manuscript.

8. Optimizing Your Paper for Discoverability (SEO)

Optimizing your paper for discoverability, also known as search engine optimization (SEO), can significantly increase its visibility and impact. By using relevant keywords, structuring your paper effectively, and promoting it online, you can make it easier for other researchers to find and cite your work. CONDUCT.EDU.VN offers SEO strategies for researchers.

8.1 Keyword Research and Selection

Keywords are words or phrases that people use to search for information online. To optimize your paper for discoverability, you should:

• Identify relevant keywords: Identify keywords that are relevant to your research topic.
• Use keyword research tools: Use keyword research tools to find keywords that are frequently searched for.
• Include keywords in your title, abstract, and keywords list: Include your keywords in your title, abstract, and keywords list.

8.2 Structuring Your Paper for Readability

A well-structured paper is easier to read and understand, which can improve its discoverability. To structure your paper for readability, you should:

• Use clear and concise headings: Use clear and concise headings to break up your paper into logical sections.
• Use bullet points and lists: Use bullet points and lists to present information in an organized manner.
• Use visuals: Use visuals, such as figures and tables, to illustrate your points.

8.3 Promoting Your Paper Online

Promoting your paper online can significantly increase its visibility and impact. To promote your paper online, you should:

• Share your paper on social media: Share your paper on social media platforms such as Twitter, Facebook, and LinkedIn.
• Create a ResearchGate profile: Create a ResearchGate profile and upload your paper.
• Contact relevant researchers: Contact relevant researchers and let them know about your paper.

8.4 Monitoring Your Paper’s Impact

Monitoring your paper’s impact can help you assess its effectiveness and identify areas for improvement. To monitor your paper’s impact, you should:

• Track citations: Track the number of times your paper has been cited by other researchers.
• Monitor downloads: Monitor the number of times your paper has been downloaded.
• Check Altmetric scores: Check the Altmetric scores to see how your paper is being discussed online.

9. Preparing Figures and Tables Effectively

Figures and tables are essential components of scientific papers. They allow you to present data in a clear and concise manner, making it easier for readers to understand your findings. However, poorly prepared figures and tables can be confusing and misleading. To prepare figures and tables effectively, you should:

9.1 Choosing the Right Type of Visual

The type of visual you choose will depend on the type of data you are presenting. Some common types of visuals include:

• Graphs: Use graphs to show relationships between variables.
• Tables: Use tables to present numerical data in an organized manner.
• Photographs: Use photographs to show images of objects or phenomena.
• Diagrams: Use diagrams to illustrate processes or concepts.

9.2 Ensuring Clarity and Accuracy

Clarity and accuracy are essential for effective figures and tables. To ensure clarity and accuracy, you should:

• Label axes and columns clearly: Label the axes of graphs and the columns of tables clearly and concisely.
• Use appropriate units: Use appropriate units for all measurements.
• Include error bars: Include error bars on graphs to show the uncertainty in your data.
• Use a clear and concise caption: Write a clear and concise caption that describes the figure or table.

9.3 Following A&A Formatting Guidelines

A&A has specific formatting guidelines for figures and tables. To ensure that your figures and tables meet these guidelines, you should:

• Use the correct font size and style: Use the correct font size and style for labels and captions.
• Use appropriate line weights: Use appropriate line weights for lines and borders.
• Use a consistent style: Use a consistent style for all figures and tables in your manuscript.

9.4 Making Figures Accessible

Make your figures accessible to readers with disabilities by:

• Providing alt text: Provide alt text for all figures so that screen readers can describe the figure to visually impaired readers.
• Using high contrast: Use high contrast colors to make your figures easier to see.
• Avoiding the use of color alone to convey information: Avoid using the use of color alone to convey information, as this may be difficult for colorblind readers to understand.

10. Frequently Asked Questions (FAQ) About A&A Author Guidelines

This section addresses some frequently asked questions about the A&A author guidelines, providing quick and concise answers to common concerns. For more detailed information, please consult the full A&A author guide or visit CONDUCT.EDU.VN.

Q1: Where can I find the most up-to-date version of the A&A author guide?

A: The most up-to-date version of the A&A author guide can be found on the Astronomy & Astrophysics website or through CONDUCT.EDU.VN.

Q2: Does A&A accept papers written in both British and American English?

A: Yes, A&A accepts papers written in both British and American English, but consistency is key. Choose one style and stick to it throughout the manuscript.

Q3: How should I format my references according to A&A style?

A: A&A has a specific citation style that must be followed. Detailed instructions on reference formatting can be found in the A&A author guide.

Q4: What should I do if I am unsure about the meaning of a particular guideline?

A: If you are unsure about the meaning of a particular guideline, consult with experienced colleagues or contact the A&A editorial office for clarification. You can also find helpful resources on CONDUCT.EDU.VN.

Q5: Is it necessary to hire a professional editor to review my manuscript before submission?

A: While it is not mandatory, it is highly recommended, especially if you are not a native English speaker or if you are unsure about the quality of your writing. Professional editing services can significantly improve the clarity and accuracy of your paper.

Q6: How can I ensure that my figures and tables are clear and effective?

A: Ensure that your figures and tables are clearly labeled, use appropriate units, include error bars, and have a clear and concise caption. Also, follow A&A’s formatting guidelines for figures and tables.

Q7: What is plagiarism, and how can I avoid it?

A: Plagiarism is the act of presenting someone else’s work as your own, without giving proper credit. To avoid plagiarism, always cite your sources, use quotation marks when quoting someone else’s words, and paraphrase carefully.

Q8: How can I optimize my paper for discoverability?

A: Optimize your paper for discoverability by using relevant keywords, structuring your paper effectively, and promoting it online. Include keywords in your title, abstract, and keywords list.

Q9: What are the ethical considerations I should keep in mind when publishing a scientific paper?

A: Ethical considerations include avoiding plagiarism and self-plagiarism, ensuring data integrity and reproducibility, declaring conflicts of interest, and following authorship guidelines.

Q10: Where can I find additional resources and support for writing scientific papers?

A: Additional resources and support for writing scientific papers can be found on CONDUCT.EDU.VN, which provides detailed guides, templates, checklists, and links to other helpful websites.

Navigating the intricacies of scientific publishing doesn’t have to be daunting. Whether you’re grappling with style conventions or seeking to elevate your manuscript’s clarity, CONDUCT.EDU.VN is your trusted partner. Our comprehensive resources empower you to overcome challenges, ensuring your work meets the highest standards of excellence. Don’t let uncertainty hold you back—visit conduct.edu.vn today and unlock the tools you need to publish with confidence. Contact us at 100 Ethics Plaza, Guideline City, CA 90210, United States. Whatsapp: +1 (707) 555-1234.