Structure changes in Er160 from low to ultrahigh spin

A spectroscopic investigation of the γ decays from excited states in Er160 has been performed in order to study the changing structural properties exhibited from low spin up toward ultrahigh spin (I~60). The nucleus Er160 was populated by the reaction Cd116(Ca48,4nγ) at a beam energy of 215 MeV, and resulting γ decays were studied using the Gammasphere spectrometer. New rotational structures and extensions to existing bands were observed, revealing a diverse range of quasiparticle configurations, which are discussed in terms of the cranked shell model. At spins around 50 there is evidence for oblate states close to the yrast line. Three rotational bands that have the characteristics of strongly deformed triaxial structures are observed, marking a return to collectivity at even higher spin. The high-spin data are interpreted within the framework of cranked Nilsson-Strutinsky calculations

Phytoplankton in a temperate-zone salt marsh: Net production and exchanges with coastal waters

Phytoplankton production and associated variables were measured in Flax Pond, a 52 ha salt marsh on the north shore of Long Island, New York, from July 1972 to October 1973. Measurements made up to five times per day, once per week, yielded a mean annual net primary production, determined by the 14 C technique, of 20.5 mg C/m 3 /h; daily means were as high as 60.0 mg C/m 3 /h. However, when productivity was calculated for the entire marsh ecosystem, the shallow water in the salt marsh produced only 11.7 g C/m 2 of marsh/year. There was a net flux of phytoplankton from the coastal waters into the marsh; during the summer up to 0.2 g chlorophy 11/m 2 of marsh was carried in with the tides daily and remained in the marsh. Analysis of the productivity data, as well as variables associated with productivity (pH, standing crop, nutrients, extinction coefficient), indicated that the aquatic portion of the marsh behaved more as a net consumer rather than a net producer of phytoplankton.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46630/1/227_2004_Article_BF00391561.pd

Diverse collective excitations in 159Er up to high spin

A spectroscopic investigation of the γ decays from excited states in 159Er has been performed to study the changing structural properties exhibited as ultrahigh spins (I>60) are approached. The nucleus of 159Er was populated by the reaction 116Cd(48Ca,5nγ) at a beam energy of 215 MeV, and the resulting γ decays were studied using the Gammasphere spectrometer. New rotational bands and extensions to existing sequences were observed, which are discussed in terms of the cranked shell model, revealing a diverse range of quasiparticle configurations. At spins around 50, there is evidence for a change from dominant prolate collective motion at the yrast line to oblate non-collective structures via the mechanism of band termination. A possible strongly deformed triaxial band occurs at these high spins, which indicates collectivity beyond 50. The high-spin data are interpreted within the framework of cranked Nilsson-Strutinsky calculations

Degradation of mangrove leaf litter by the tropical sesarmid crab Chiromanthes onychophorum

In high-diversity tropical mangrove swamps, the relationship between the breakdown to detritus of mangrove plant litter and secondary production of associated estuaries is little understood. This study examined one step in this relationship, the breakdown of mangrove leaf litter to detrital-sized particles by the sesarmid crab Chiromanthes onychophorum , locally very abundant in mangrove swamps of peninsular Malaysia. Contents of the proventriculus (stomach) and of the posterior hindgut, including rectum, were analyzed and particle sizes were measured. Gut contents consisted of more than 95% by volume of mangrove leaf fragments. Particles in the hindgut were of smaller mean size than those in the proventriculus. It is concluded that C. onychophorum consumes fallen leaves or their fragments, incompletely digests them, and returns them to the environment as fecal matter in a more finely-divided state than when they were ingested. C. onychophorum may therefore be a significant agent of mangrove leaf degradation to detrital-sized particles in swamp areas where it is abundant.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46633/1/227_2004_Article_BF00455032.pd