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Neutron velocity spectroscopy using the Nevis synchrocyclotron. Progress report, July 30, 1972--June 30, 1973

Description: The period August 1, 1972, to June 30, 1973, was marked by the continuing of the analysis of the vast amounts of data obtained during 1968 and 1970 pulsed-neutron time-of-flight spectroscopy runs using the Nevis Synchrocyclotron. Many major research papers from that period have now appeared in print. The numerous evolving results for even A nuclei having atomic mass 150 < A < 190 have given first conclusive (and growing) confirmation of Dyson's theories concerning level spacing systematics. Monte Carlo studies leading to a better understanding of the implications of these theories have also been published. The important paper on /sup 238U and /sup 232/Th is now published, as is that for the Yb isotopes. Papers on the W isotopes, on Na, and on K have been submitted for publication. Results for the Gd and Sm isotopes, for the Cd isotopes, for Ta, for argon, for calcium, for sodium, for potassium, for copper (63/Cu and /sup 65/Cu), and for chlorine are contained in the full report COO- 2174-15. (auth)
Date: June 1, 1973
Creator: Rainwater, J.
Partner: UNT Libraries Government Documents Department

Secondary succession: Composition of the vegetation and primary production in the field-to-forest at Brookhaven, Long Island, N.Y.

Description: Natural communities respond to disruption through a series of changes in plant and animal communities that are broadly predictable. The field-to-forest sere of central Long Island follows the pattern set forth earlier for the Piedmont of North Carolina and for New Jersey. The communities of herbs that occur in the years immediately after abandonment are followed by an Andropogon stage which is replaced before the 20th year by pine forest. The pine is replaced in the next 25 years by oak-pine, which in the normal Course is followed by oak-hickory. With repeated burning the oak-pine stage in various combinations of oaks and pine may be maintained indefinitely. Diversity, measured as number of species per unit land area, increased in this sere through the 3-5th years after abandonment to a maximum, dropped, and rose again in the later forest stages. Exotics were a conspicuous part of the communities of the earlier stages but their importance diminished as succession progressed and their contribution to net production was zero beyond the 20th year. The removal of exotics would probably not have changed the pattern of diversity appreciably. Net primary production increased with succession in this sere with major changes occurring as life-forms of the dominants shifted to woody plants. The peak net production was in the most mature forest, about 1200 g/m{sup 2}/yr. Root/shoot ratios declined from 4-5 in the early stages of succession to 0.3-0.5 with later stages. The standing crop of organic matter including humus throughout the sere was about 15 times the net production, indicating a halftime of residence for all organic matter throughout the sere of about 10 years.
Date: August 23, 1973
Creator: Woodwell,G.M.; Holt, B. R. & Flaccus, E.
Partner: UNT Libraries Government Documents Department