The Scientific Abstract The abstract is a digest of the report which should specify the problem and briefly state the conclusion or results. Informative rather than descriptive, it should state what the report tells, the methods and type of data used, not what the report is about. The abstract is prepared from information already written in the report. Most abstracts begin with a statement emphasizing the work done, the content of the report, or the findings/ conclusions. From Report Planning, Preparation, and Review Workshop, USGS CAWater Resources District, April 1991 The abstract is a digest of the report and should be concise. Much of a report's usefulness depends on the adequacy of the abstract. A well-prepared abstract enables readers to identify the basic content of a report quickly and accurately, and thus to decide whether they need to read the document in its entirety. For the author, the abstract is an opportunity to state, in condensed form, what s/he considers to be the real contribution to knowledge. Authors must bear in mind that many people will read no more than titles and abstracts of their reports Indicative abstracts are used for data compilations containing no conclusions and tell the reader about the general content of the report. Informative abstracts contain the essential facts and conclusions in the report. The abstract should contain the same basic information and tone (balance, emphasis) as that of the report. When findings are too numerous for all to be included, give priority to significant discoveries, findings that contradict previous theories or results, findings relevant to a practical problem, or findings that are important to a cooperator or other funding agency. Do not state what the report contains, but, rather, what it contributes. The abstract should also include: 1. Information that accurately reflects the article's title and content; 2. A topic sentence about the report's major thesis; 3. Geographic location; 4. The problems, primary objectives, and scope of study or the reasons why the report was written, unless obvious; 5. The type of report (e.g. water-quality study); 6. The methodology, especially if new techniques or special procedures; 7. Type and accuracy of data collected and used; 8. Whether numerical values are new or derived, of a single observation or repeated measurements; 9. Principal findings; 10. Conclusions, including whether results meet the objectives of the study, how the results can be applied, suggestions for further study. Water Resources Division Publications Guide, 1986 Any but the briefest scientific paper is preceded by an informative abstract. Early rough draft summaries must not be made over into abstracts; the abstract should be a concise summary of the completed manuscript. Preparation of a good abstract--one that summarizes the important content of the report and nothing more--deserves as much thought, rewriting, and polishing as any other part of the report. An author's conclusions are the most valuable part of a report or abstract, but within space limitations the abstract should also indicate the method of attack and the type of data used and should clearly orient the paper in place and function. It should supplement the paper, not duplicate it, and it should not be a mere expansion of the table of contents. The Survey sets no specific limits on the lengths of abstracts in its publications but short abstracts are more likely to be read than long ones and are more apt to be included in their entirety in abstract journals. Suggestions to Authors of the Reports of the USGS, Seventh Edition Exposure of Delta Smelt to Multiple Pesticides during Larval and Juvenile Stages. Kuivila, K.M.*, Moon, G.E., Orlando, J.L., and Houston, J.R., U.S. Geological Survey, Sacramento, CA. 1) The cause(s) of the decline since 1983 of Delta smelt abundance in San Francisco Bay Estuary are not known. 2) One possible factor is pesticide toxicity during vulnerable larval and juvenile stages, but the concentrations of pesticides are not well characterized in Delta smelt spawning and nursery habitat. 3) The objective of this study was to quantify the exposure of Delta smelt to dissolved pesticides during these sensitive life stages. 4) Water samples were analyzed for pesticides from two major spawning areas (northwestern and central Sacramento-San Joaquin Delta) and one nursery area (Suisun Bay) during the spring and summer of 1998 and 1999. 5) The two spawning areas are closer to sources of pesticides than the nursery area and, as would be expected, more pesticides were detected at higher concentrations. Pesticides detected included carbaryl, carbofuran, diazinon, eptam, metolachlor, molinate, simazine, sulfotep, thiobenbarb, and trifluralin with maximum concentrations ranging from 0.46 to 7.7 ug/L. 6) Although these concentrations are well below LC50 values for the individual pesticides, the combination of multiple pesticides could potentially cause sublethal effects, especially during early development of the larvae. In addition, the duration of exposure to elevated pesticide concentrations was weeks to months whereas most toxicity testing is only conducted for days to weeks. 7) In a concurrent field study, University of California at Davis (UCD) scientists are measuring biomarkers, histopathology, DNA fragmentation, and growth rates of Delta smelt. The exposure results from this study will be related to the effects observed in the UCD study. I put the numbers in to show what an abstract should contain: 1. Big picture sentence about general problem 2) More specific sentence about problem addressed in this abstract 3) Objective of study/abstract 4) Method/approach - what we did 5) Results 6) Take home message(s) 7) What is next? Ongoing or future research direction on this topic or back to bigger picture. I tend to do it as an hourglass : big - small - big Summary of Suspended-Solids Concentration Data, San Francisco Bay, California, Water Year 1997 By Paul A. Buchanan and David H. Schoellhamer Abstract Suspended-solids concentration data were collected in San Francisco Bay during water year 1997 (October 1, 1996-September 30, 1997). Optical backscatterance sensors and water samples were used to monitor suspended solids at two sites in Suisun Bay, three sites in Central San Francisco Bay, and three sites in South San Francisco Bay. Sensors were positioned at two depths at most sites. Water samples were collected periodically and were analyzed for concentrations of suspended solids. The results of the analyses were used to calibrate the electrical output of the optical backscatterance sensors. This report presents the data-collection methods used and summarizes the suspended-solids concentration data collected from October 1996 through September 1997 (water year 1997). Calibration plots and plots of edited data for each sensor also are presented. Environmental Behavior and Fate of Methyl tert-Butyl Ether (MTBE) By Paul J. Squillace, James F. Pankow, Nic E. Korte, and John S. Zogorski U.S. Department of the Interior - U.S. Geological Survey National Water Quality Assessment Program (NAWQA) Fact Sheet FS-203-96 (Revised 2/98) Abstract When gasoline that has been oxygenated with methyl tert-butyl ether (MTBE) comes in contact with water, large amounts of MTBE can dissolve; at 25 degrees Celsius the water solubility of MTBE is about 5,000 milligrams per liter for a gasoline that is 10 percent MTBE by weight. In contrast, for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 milligrams per liter MTBE sorbs only weakly to soil and aquifer materials; therefore, sorption will not significantly retard MTBE's transport by ground water In addition, MTBE generally resists degradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 days in a regional airshed. MTBE in the air tends to partition into atmospheric water, including precipitation. However, washout of gas-phase MTBE by precipitation would not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation is nevertheless strong enough to allow for up to 3 micrograms per liter or more inputs of MTBE to surface and ground water. NOTES ON NUMERICAL RELIABILITY OF SEVERAL STATISTICAL ANALYSIS PROGRAMS by J. M. Landwehr1 and G. D. Tasker2 U. S. Geological Survey, 431 National Center, Reston, VA 20192 ABSTRACT This report presents a benchmark analysis of several statistical analysis programs currently in use in the USGS. The benchmark consists of a comparison between the values provided by a statistical analysis program for variables in the reference data set ANASTY and their known or calculated theoretical values. The ANASTY data set is an amendment of the Wilkinson NASTY data set that has been used in the statistical literature to assess the reliability (computational correctness) of calculated analytical results. HCDN: A U.S. Geological Survey streamflow data set for the United States for the study of climate variations, 1874 - 1988 USGS Open-File Report 92-129 By J.R. Slack and Jurate Maciunas Landwehr ABSTRACT Records of streamflow can provide an account of climatic variation over a hydrologic basin. The ability to do so is conditioned on the absence of confounding factors that diminish the climate signal. A national data set of streamflow records that are relatively free of confounding anthropogenic influences has been developed for the purpose of the variation in surface-water conditions throughout the United States. Records in the U.S. Geological Survey (USGS) National Water Storage and Retrieval System (WATSTORE) data base for active and discontinued streamflow gaging stations through water year 1988 (that is, through September 30, 1988) were reviewed jointly with data specialists in each USGS District office. The resulting collection of stations, each with its respective period of record satisfying the qualifying criteria, is called the Hydro-Climatic Data Network, or HCDN. The HCDN consists of 1,659 sites throughout the United States and its territories, totaling 73,231 water years of daily mean discharge values. For each station in the HCDN, information necessary for its identification, along with any qualifying comments about the available record and a set of descriptive watershed characteristics are provided in tabular format in this report, both on paper and on computer disk (enclosed). For each station in the HCDN, the appropriate daily mean discharge values were compiled, and statistical characteristics, including monthly mean discharges and annual mean, minimum and maximum discharges, were derived. The discharge data values are provided in a companion report.