Über krystallisierte Acetylcellulose

The Science of Nature -     

Vertical movements, behavior, and habitat of bigeye tuna (Thunnus obesus) in the equatorial eastern Pacific Ocean, ascertained from archival tag data

The results presented in this report are based on analyses of 16,721 days of data downloaded from 96 archival tags recovered from bigeye tuna (Thunnus obesus; 54–159 cm in length, 0.97–5.44 years of age) at liberty from 31 to 1,508 days in the equatorial eastern Pacific Ocean. Analyses of daily timed depth and temperature records resulted in the classification of the data into three daily behavior types: characteristic, associative (associated with floating objects), and other. There is a significant positive correlation between the proportion of time fish exhibit characteristic behavior and increasing length, and significant negative correlations between the proportion of time bigeye exhibit associative and other behavior with increasing length. For the smallest (54–80 cm) to largest (100–159 cm) length classes, the vertical habitats utilized when exhibiting non-associative behaviors were 99 and 98% of the time above the thermocline depth (60 m) during the night, at the same average depth of 34 m, and 60 and 72% of the time below the thermocline during the day at average depths of 163 and 183 m, respectively. For the same smallest to largest length classes, when exhibiting associative behavior, the average nighttime and daytime depths were 25 and 21, and 33 and 37 m, respectively. The apparent effects of the environment on the behavior of the fish are discussed.     

Book review

Environmental Management, (3 Volumes) Editors B. Nath, L. Hens and D. Devuyst (Brussels, Vubpress: 1993. Approx. 890 Pp. Paperback) (£25 Per Volume) Isbn 90 5487 035 4-6

The Chemistry and Deposition of Nitrogen Species in the Troposphere, Editor A. T. Cocks, Publisher Royal Society of Chemistry, 1993, X + 134pp., Isbn 0 85186 355 8, Price £35.00.     

Illinois State Water Survey Bulletin 75: New Precipitation Frequency Study for Illinois

Storm frequency estimates and their temporal distributions are important in determining estimates of runoff or peak flow rates in many engineering and hydrological problems. Illinois State Water Survey Bulletin 70 has been serving as the design rainfall standard in Illinois since its publication in 1989. Although Bulletin 70 represented the best available data at the time of its publication, the standards needed to be reevaluated and updated after more than three decades and with the growing evidence of the nonstationary nature of heavy precipitation. The trends in heavy precipitation in Illinois prompted the creation of a new frequency study named Bulletin 75, providing precipitation frequencies for event durations ranging from 5 min to 10 days and for recurrence intervals ranging from 2 months to 500 years. The results are presented for the same 10 geographic sections in Illinois as in Bulletin 70 to maintain the continuity of hydrologic studies and compatibility with regulations. The primary goal of this paper is to outline some of the key methodological issues and challenges, to compare the results with the previous sources, and to highlight the effects of the changing precipitation standards on the development of amendments to existing ordinances. Lake County in Illinois, as one of the most affected urban areas with the highest change in heavy precipitation, was selected to illustrate issues related to the application of modified precipitation standards.