Preliminary Evaluation of Baits and Traps for Harvesting Orconectid Crayfish from Earthen Ponds

Four commercially available crayfish baits and two trap types were evaluated for efficiency in trapping Orconecres virilis and O. immunis from 13 unmanaged, contiguous earthen ponds in southern Illinois from May through October 1988. Specifically, this study compared three long-life baits and one one-day bait to gizzard shad, and four-funnel submerged pillow traps to three-funnel stand-up pyramid traps in matched-pair comparisons. Data from O. immunis harvest was not included in the final evaluation because of the relatively low numbers caught (343). The three long-life baits attracted significantly more O. virilis than did gizzard shad, but the attractability of the one-day bait was not significantly different from shad. There were no significant differences between four-funnel pillow traps and three-funnel pyramid traps or between catch per unit effort from deep or shallow ends of typical culture ponds. These data indicate that wild populations of O. virilis are susceptible to trapping with typical baits and traps used in the southern United States, and these methods may be more effective than those currently employed.     

Cytologic features of a meningioma in a dog

Meningiomas are one of the most common nervous system tumors in dogs. They are mostly solitary, benign, intracranial tumors of the transitional type. Tentative diagnosis can usually be made on historical data, clinical and neurological signs, and radiographs, with an antemortem diagnosis confirmed by exploratory surgery and histologic evaluation of biopsy. The literature contains many reports of the gross, histological and ultrastructural morphology of canine meningiomas, but little on the cytologic features of these tumors. This report describes the cytologic appearance of an intracranial meningioma in a 9-year-old Miniature Schnauzer.     

Efficacy of acyclovir against herpesvirus infection in Quaker parakeets.

We evaluated the efficacy of acyclovir against experimentally induced herpesvirus infection (Pacheco's parrot disease) in Quaker parakeets. Thirty-two of 40 birds were challenge-exposed with 0.1 ml of a suspension of herpesvirus (10(4) median cell culture infective doses [CCID50]) given IM. Treatment with acyclovir was started 24 hours later and was continued for 7 days. The birds were allotted to 5 groups of 8 birds each. There was a considerable difference in mortality between groups 1-5. Of 8 bird in each group, 6 died in group 1 (control), 1 died in group 2 (gavage), 3 died in group 3 (low dose, IM), 4 died in group 4 (high dose, IM), and none died in group 5 (contact controls). There was a significant (P = 0.023) difference in mortality between groups 1 and 2, thus the oral form of acyclovir administered by gavage was the most efficacious therapeutic regimen. Clinical signs and death occurred after discontinuation of acyclovir in groups 2 and 3, whereas the mean time of death for the control group was 6 days after challenge exposure. Herpesvirus was recovered by inoculation of chick embryo cell culture with pooled tissue suspensions from all birds that died. Histologic evidence of herpesvirus infection was found in most birds that died, with the control group having the most severe lesions. Surviving Quaker parakeets were transferred to cages with seronegative Quaker parakeets with no known exposure to herpesvirus. There have been no deaths attributable to herpesvirus infection in a period exceeding 2 years.     

Investigations into the toxicity of Echium plantagineum in sheep: 2. Pen feeding experiments

In a pen feeding trial fresh Echium plantagineum was fed as the sole diet to crossbred sheep with or without a history of previous access to the plant. Control groups received a diet of lucerne chaff and oats. During the trial, sheep on the Echium diet lost weight and deaths occurred with histological evidence of excessive copper accumulation, usually accompanied by pyrrolizidine alkaloid damage, in the liver and biochemical evidence of liver toxicity. It is concluded that E. plantagineum alone is not a suitable fodder for sheep and can be toxic due to its pyrrolizidine alkaloid content and high copper to molybdenum ratio.     

The radio-frequency single-electron transistor (RF-SET): A fast and ultrasensitive electrometer

A new type of electrometer is described that uses a single-electron transistor (SET) and that allows large operating speeds and extremely high charge sensitivity. The SET readout was accomplished by measuring the damping of a 1.7-gigahertz resonant circuit in which the device is embedded, and in some ways is the electrostatic "dual" of the well-known radio-frequency superconducting quantum interference device. The device is more than two orders of magnitude faster than previous single-electron devices, with a constant gain from dc to greater than 100 megahertz. For a still-unoptimized device, a charge sensitivity of 1.2 x 10(-5) e/hertz was obtained at a frequency of 1.1 megahertz, which is about an order of magnitude better than a typical, 1/f-noise-limited SET, and corresponds to an energy sensitivity (in joules per hertz) of about 41 Planck's over 2pi.     

Lithospheric Contributions to Arc Magmatism: Isotope Variations Along Strike in Volcanoes of Honshu, Japan

Major chemical exchange between the crust and mantle occurs in subduction zone environments, profoundly affecting the chemical evolution of Earth. The relative contributions of the subducting slab, mantle wedge, and arc lithosphere to the generation of island arc magmas, and ultimately new continental crust, are controversial. Isotopic data for lavas from a transect of volcanoes in a single arc segment of northern Honshu, Japan, have distinct variations coincident with changes in crustal lithology. These data imply that the relatively thin crustal lithosphere is an active geochemical filter for all traversing magmas and is responsible for significant modification of primary mantle melts.