【文章內(nèi)容簡(jiǎn)介】 n poses the questions addressed in the early part of Results. Beyond this point, the anization of Results differs from one paper to another. In some papers, the results are presented without extensive discussion, which is reserved for the following section. This is appropriate when the data in the early parts do not need to be interpreted extensively to understand why the later experiments were done. In other papers, results are given, and then they are interpreted, perhaps taken together with other findings not in the paper, so as to give the logical basis for later experiments. The fourth section is the Discussion. This section serves several purposes. First, the data in the paper are interpreted。 that is, they are analyzed to show what the authors believe the data show. Any limitations to the interpretations should be acknowledged, and fact should clearly be separated from speculation. Second, the findings of the paper are related to other findings in the field. This serves to show how the findings contribute to knowledge, or correct the errors of previous work. As stated, some of these logical arguments are often found in the Results when it is necessary to clarify why later experiments were carried out. Although you might argue that in this case the discussion material should be presented in the Introduction, more often you cannot grasp its significance until the first part of Results is given. Finally, papers usually have a short Acknowledgements section, in which various contributions of other workers are recognized, followed by a Reference list giving references to papers and other works cited in the text. Papers also contain several Figures and Tables. These contain data described in the paper. The figures and tables also have legends, whose purpose is to give details of the particular experiment or experiments shown there. Typically, if a procedure is used only once in a paper, these details are described in Materials and Methods, and the Figure or Table legend refers back to that description. If a procedure is used repeatedly, however, a general description is given in Materials and Methods, and the details for a particular experiment are given in the Table or Figure legend. Variations on the anization of a paper In most scientific journals, the above format is followed. Occasionally, the Results and Discussion are bined, in cases in which the data need extensive discussion to allow the reader to follow the train of logic developed in the course of the research. As stated, in some journals, Materials and Methods follows the Discussion. In certain older papers, the Summary was given at the end of the paper. The formats for two widelyread journals, Science and Nature, differ markedly from the above outline. These journals reach a wide audience, and many authors wish to publish in them。 accordingly, the space limitations on the papers are severe, and the prose is usually highly pressed. In both journals, there are no discrete sections, except for a short abstract and a reference list. In Science, the abstract is selfcontained。 in Nature, the abstract also serves as a brief introduction to the paper. Experimental details are usually given either in endnotes (for Science) or Figure and Table legends and a short Methods section (in Nature). Authors often try to circumvent length limitations by putting as much material as possible in these places. In addition, an increasingly mon practice is to put a substantial fraction of the lessimportant material, and much of the methodology, into Supplemental Data that can be accessed online. Many other journals also have length limitations, which similarly lead to a need for conciseness. For example, the Proceedings of the National Academy of Sciences (PNAS) has a sixpage limit。 Cell severely edits many papers to shorten them, and has a short word limit in the abstract。 and so on. In response to the pressure to edit and make the paper concise, many authors choose to condense or, more typically, omit the logical connections that would make the flow of the paper easy. In addition, much of the background that would make the paper accessible to a wider audience is condensed or omitted, so that the lessinformed reader has to consult a review article or previous papers to make sense of what the issues are and why they are important. Finally, again, authors often circumvent page limitations by putting crucial details into the Figure and Table legends, especially when (as in PNAS) these are set in smaller type. Back to outline 2. Reading a scientific paper Although it is tempting to read the paper straight through as you would do with most text, it is more efficient to anize the way you read. Generally, you first read the Abstract in order to understand the major points of the work. The extent of background assumed by different authors, and allowed by the journal, also varies as just discussed. One extremely useful habit in reading a paper is to read the Title and the Abstract and, before going on, review in your mind what you know about the topic. This serves several purposes. First, it clarifies whether you in fact know enough background to appreciate the paper. If not, you might choose to read the background in a review or textbook, as appropriate. Second, it refreshes your memory about the topic. Third, and perhaps most importantly, it helps you as the reader integrate the new information into your previous knowledge about the topic. That is, it is used as a part of the selfeducation process that any professional must continue throughout his/her career. If you are very familiar with the field, the Introduction can be skimmed or even skipped. As stated above, the logical flow of most papers goes straight from the Introduction to Results。 accordingly, the paper should