INTRODUCTION
When speaking about the abstract readers usually think of abstracts used in primary journals that enable scientists to keep up in active areas of research. An abstract should provide a brief summary of each of the main sections of the paper. American National Standards Institute defined "a well-prepared abstract" as one that "enables readers to identify the basic content of a document quickly and accurately, to determine its relevance to their interests, and thus to decide whether they need to read the document in its entirety". Scientists should master the fundamentals of abstract preparation for several reasons:
• a "heading" abstract is required by most journal;
• a "meeting" or "conference" abstract is a requirement for participation in scientific meetings - participation being sometimes determined on the basis of submitted abstracts;
• Many people will read the abstract, in the original journal or in any of secondary publications, either in printed edition or in online computer searches.
TYPES OF ABSTRACTS
There are two types of abstracts. The abstract used in primary journals is often referred to as an informative abstract. It is designed to condense the paper. It should briefly state the principal objectives and scope of the investigation, describe the methods employed, summarize the results and state the principal conclusions. That abstract is used as a "heading" in most journals today and often supplants the need for reading the full paper. Another common type of abstract is referred to as an indicative, somethimes called a descriptive, abstract. This type of abstract is designed to indicate the subjects dealt with in a paper. Because of its descriptive rather then substantive nature, it can seldom serve as a substitute for the full paper. Thus, it should not be used as "heading" abstracts in research papers, but may be used in other types of publications such as review papers and conference reports. The indicative abstracts are often of great value to reference librarians. Whatever the abstract used in the primary journals, some rules are usually applied and the following should be remembered :
• The abstract shoud never give any information or conclusion that is not stated in the paper.
• The abstract should not exceed 250 words and should be designed to define clearly what is dealt with in the paper.
• Most or all abstracts should be written in the past tense, because it refers to work done.
• The abstract should be typed as a single papragraph. Some medical journals now run "structured" abstracts consisiting of a few brief paragraphs.
• The language should be familiar to the potential reader.
• Use of obscure abbreviations and acronyms should be omitted.
• Unless a long term is used several times within an abstract, do not abbreviate the term.
• The literature must not be cited, except in rare instances, such as modification of a previously published method.
• Write the paper before you write the abstract, whenever possible.
CONFERENCE ABSTRACT
There are certain differences between "heading" abstract and "conference" abstract. However, the differences are less than previously stated and the most of the above rules apply to both types of abstracts. The essential purpose of the "conference" abstract is to attract and gain the acceptance of the conference organiser. The hallmark of an effective abstract is to avoid fine detail but to capture the key aspects of the presentation. Since the conference may be many months ahead, you may not know what data you will have by then or whether the findings will be positive or negative. Thus, you should give just enough to make your presentation sound novel and interesting, emphassising any new techniques or interseting uses of old ones. Give some data if you can and avoid the off-putting expression ". . . will be discussed". In recent years, the conference organizers usually set word length for abstracts which must be strictly adhered to, otherwise the abstract may be rejecetd e. g. states that the abstract must be no longer than 2000 characters(for online version) or restricted number of words (usally up to 250 words) , and must have sections labelled as folllows: Objective(s) , Methods, Results and Conclusion(s) . Titles should be used to capture the attention of the audience. They are short(often less than 10 words) and state the subject of the paper but never the conclusion. Setting the names of the authors and their affiliations are aslo predetermined by the instructions. In case anyone might want to get in touch with you after the conference, it is suggested to include your address, phone, fax and e-mail numbers. In comparison to primary journal literature abstracts where bibliographic, figures, or table-references are not recommended, in the "conference" abstracts it is allowed and even suggested to present results in figures or tables. It is helpful to the participants to include any key references in the abstract, so that they will be readily avilable in the abstract books. It is usually allowed to the participants to word the text, in the online abstract version only, up to the deadline for abstract submisson but it is also necessary to follow the conference instructions, such as fitting the abstract into camera-ready frame on the abstract form provided. In recent times, "conference abstracts" have fallen into disrepute because some conference organisers have published them no matter whether they were referred or not, whether they were accepted for the conference or not, and, if accepted, whether the authors had turned up and presented them or not. It may also be impossible to change the abstract before it enters the public domain, under your name, if other participants show your ideas or interpretations to be wrong. Therefore, it is of fundamental importance that the abstract be written clearly and simply. If you cannot attract the interest of the reviewer/conference organiser in your abstract, your cause may be lost.
REFERENCES
1. Day AR. How to write and published a scientific paper. Phoenix-New York: Oryx Press; 1998. p. 29-32.
2. Whmister F W. Biomedical research. How to plan, publish and present it. London: Springer. 1997. p. 155-6.
3. Savić J. Kako napisati, objaviti i vrednovti naučno delo u biomedicini. Beograd: Kultura; 1996. p. 8-56.
4. Philips JS. Principles of the scientific paper. In: EAU Publication Committee - Chairman: Prof. C. Schulman. editor. How to: write and publish scientific papers. Proceedings of the the educational symposium. "Effective Communications for Urologists"; 1999. p. 7-10.