Drift of Riffle Beetles (Coleoptera: Elmidae) in a Small Illinois Stream

The daily and seasonal periodicities of drift of riffle beetles were examined in Polecat Creek. Illinois. during the spring and summer of 1978. Drift samples were collected from a single site over four 24-h periods. Dubiraphia vittata adults comprised 72% of the total numerical sample and exhibited greatest mean daily drift density in September. Macronychus glabratus adults were also common in drift collections, with highest densities re- corded during .\u27.lay and August. The drift of D. vittata and M. glabratus exhibited distinct patterns of die! periodicity with peaks occurring in the early hours of darkness. Substantial differences in drift densities between adult and larval stages were evident for D. vittata and M. glabratus. in both cases the adults were more prone to drift

Methods and standards development for three-dimensional mapping of the Antioch Quadrangle, Lake County, Illinois a pilot study

The Pilot Study for the Central Great Lakes Geologic Mapping Coalition (CGLGMC) focused on the Antioch Quadrangle, Lake County, Illinois developing a series of maps and digital products, several protocols for database development and maintenance and field procedures to acquire and integrate drilling and geophysical data from a quadangle area featuring complex glacial geology over a 25,000 year period.U.S. Geological Survey, Central Great Lakes Geologic Mapping CoalitionOpe

Inhibition of the Aminopeptidase from \u3cem\u3eAeromonas proteolytica\u3c/em\u3e by l-leucinethiol: Kinetic and Spectroscopic Characterization of a Slow, Tight-binding Inhibitor–enzyme Complex

The peptide inhibitor l-leucinethiol (LeuSH) was found to be a potent, slow-binding inhibitor of the aminopeptidase from Aeromonas proteolytica (AAP). The overall potency (KI*) of LeuSH was 7 nM while the corresponding alcohol l-leucinol (LeuOH) was a simple competitive inhibitor of much lower potency (KI=17 μM). These data suggest that the free thiol is likely involved in the formation of the E·I and E·I* complexes, presumably providing a metal ligand. In order to probe the nature of the interaction of LeuSH and LeuOH with the dinuclear active site of AAP, we have recorded both the electronic absorption and EPR spectra of [CoCo(AAP)], [CoZn(AAP)], and [ZnCo(AAP)] in the presence of both inhibitors. In the presence of LeuSH, all three Co(II)-substituted AAP enzymes exhibited an absorption band centered at 295 nm, characteristic of a S→Co(II) ligand-metal charge-transfer band. In addition, absorption spectra recorded in the 450 to 700 nm region all showed changes characteristic of LeuSH and LeuOH interacting with both metal ions. EPR spectra recorded at high temperature (19 K) and low power (2.5 mW) indicated that, in a given enzyme molecule, LeuSH interacts weakly with one of the metal ions in the dinuclear site and that the crystallographically identified μ-OH(H) bridge, which has been shown to mediate electronic interaction of the Co(II) ions, is likely broken upon binding LeuSH. EPR spectra of [CoCo(AAP)]-LeuSH, [ZnCo(AAP)]-LeuSH, and [Co_(AAP)]-LeuSH were also recorded at lower temperature (3.5–4.0 K) and high microwave power (50–553 mW). These signals were unusual and appeared to contain, in addition to the incompletely saturated contributions from the signals characterized at 19 K, a very sharp feature at geff∼6.5 that is characteristic of thiolate-Co(II) interactions. Combination of the electronic absorption and EPR data indicates that LeuSH perturbs the electronic structure of both metal ions in the dinuclear active site of AAP. Since the spin–spin interaction seen in resting [CoCo(AAP)] is abolished upon the addition of LeuSH, it is unlikely that a μ-S(R) bridge is established

Balancing reliability and cost to choose the best power subsystem

A mathematical model is presented for computing total (spacecraft) subsystem cost including both the basic subsystem cost and the expected cost due to the failure of the subsystem. This model is then used to determine power subsystem cost as a function of reliability and redundancy. Minimum cost and maximum reliability and/or redundancy are not generally equivalent. Two example cases are presented. One is a small satellite, and the other is an interplanetary spacecraft