The geologically recent giant impact basins at Vesta's south pole

Dawn's global mapping of Vesta reveals that its observed south polar depression is composed of two overlapping giant impact features. These large basins provide exceptional windows into impact processes at planetary scales. The youngest, Rheasilvia, is 500 kilometers wide and 19 kilometers deep and finds its nearest morphologic analog among large basins on low-gravity icy satellites. Extensive ejecta deposits occur, but impact melt volume is low, exposing an unusual spiral fracture pattern that is likely related to faulting during uplift and convergence of the basin floor. Rheasilvia obliterated half of another 400-kilometer-wide impact basin, Veneneia. Both basins are unexpectedly young, roughly 1 to 2 billion years, and their formation substantially reset Vestan geology and excavated sufficient volumes of older compositionally heterogeneous crustal material to have created the Vestoids and howardite-eucrite-diogenite meteorites.     

Differential diagnosis and management of human-directed aggression in cats.

Human-directed aggression in cats should be evaluated as a multifactorial problem. It results from the combined actions of heredity, environment, learning, human social requirements (or needs), client interactions, lack of understanding of normal feline behavior, unrealistic client expectations, and lack of meeting the cat's basic ethologic needs. Managing human-directed aggression in cats encompasses the use of environmental modification, therapies, and, when and if needed, regulatory drugs so as to increase learning capabilities and adaptation and decrease danger to the human victims.     

Pyrethrum dermatitis.II. The allergenicity of pyrethrum oleoresin and its cross-reactions with the saline extract of pyrethrum flowers

Tests on sensitised guinea pigs have indicated that crude pyrethrum oleoresin contains two types of allergens. The more potent are compounds with similar allergenic determinants to the allergens present in the 0.9% saline extract of pyrethrum flowers which have been tentatively classified as glycoproteins or glycopeptides with molecular weights distributed between about 60 000 and 200 000. The second class of allergens is the sesquiterpene lactones, principally pyrethrosin but these are of minor importance due to their low concentration in pyrethrum oleoresin. Contrary to a recent report, no allergenic activity was obtained from pyrethrin II.     

Organophosphorus poisoning: A comparative study of the toxicity of carbophenothion to the Canada goose,the pigeon and the Japanese quail

The acute single dose oral toxicity of carbophenothion (S-4-chlorophenylthiomethyl OO-diethyl phosphorodithioate) has been determined in Canada geese (Branta canadensis), pigeons (Columba livia) and Japanese quail (Coturnix coturnix japonica). At post mortem examination gross pathological changes were observed in Canada geese and pigeons and esterase levels were determined by conventional and electrophoretic methods on extracts of liver and brain from these two species. Carbophenothion residue levels were determined in liver, brain and gizzard contents from the geese and pigeons. The overall pattern of results suggests that esterase inhibition may not be the dominant factor in carbophenothion poisoning in geese. It is suggested that a brain carbophenothion residue level of 1 part/10⁶ is indicative of death by poisoning in geese.     

Chemical modifications of the insecticide binding sites on human serum albumin: Role of indole,bilirubin, and fatty acid binding sites

Interaction of carbamate and organophosphorus insecticides with chemically modified human serum albumin was studied by solubilization and difference spectra of bound insecticides and quenching of albumin fluorescence. Chemical modification involved oxidation of 1 tryptophan and 4 histidine residues, acetylation of 4 tyrosine and 26 lysine residues, and reaction of 7 arginine residues with 1,2-cyclohexanedione. There was a decrease in binding due to modification of arginine, tryptophan, and tyrosine residues and an increased binding due to lysine acetylation. The presence of bilirubin and octanoate also decreased the binding of insecticides. Changes in fluorescence of bound ANS due to binding of insecticides to albumin indicate localized perturbation of albumin conformation. The binding of insecticides was not affected by palmitate at physiological concentrations (molar ratio less than 2) although higher fatty acid concentrations caused a decrease. These preliminary observations suggest that warfarin, indole, and bilirubin sites are probably among the multiple insecticide binding sites.     

Alteration of neutrophil function associated with coccidiosis in cattle: influence of decoquinate and dexamethasone

Twenty Holstein steers subclinically infected with coccidia were allotted to 2 groups of 10 steers each. One group received a diet containing 0.5 mg of decoquinate/kg of body weight. After 25 days on the diet, there was no difference between the groups in lymphocyte blastogenic responsiveness to mitogens; however, there were differences in neutrophil function. Lymphocytes from steers of the decoquinate-fed group had decreased random migration under agarose, enhanced cytochrome C reduction, and enhanced iodination activity. Other measures of neutrophil function evaluated (chemotactic index, Staphylococcus aureus ingestion, and antibody-dependent and -independent cell-mediated cytotoxicity) were not affected. After 30 days of decoquinate feeding, half of the cattle in each group received 5 daily IM injections of dexamethasone (0.04 mg/kg of body weight). The dexamethasone-treated steers from the group that did not have decoquinate in the diet developed clinical coccidiosis, whereas the decoquinate-treated steers remained clinically normal. Lymphocyte and neutrophil function were again evaluated for a 3-day period beginning 4 days after dexamethasone treatment was halted. Neutrophils from the steers that developed clinical coccidiosis after dexamethasone administration had significantly (P less than 0.05) inhibited random migration under agarose, cytochrome C reduction, and iodination activity, but significantly (P less than 0.01) enhanced S aureus ingestion. The feeding of decoquinate prevented the inhibition of neutrophil cytochrome C reduction and lessened the inhibition of neutrophil iodination in the dexamethasone-treated group. Dexamethasone treatment was associated with an inhibition of lymphocyte blastogenic responsiveness to phytohemagglutinin in principals as well as controls.     

Conium maculatum (poison hemlock) toxicosis in a flock of range turkeys

Five 20-week-old tom turkeys from a flock of range turkeys were presented for examination; the flock had a history of salivation, tremors, paralysis, and increased mortality. Necropsy revealed numerous seeds identified as seeds from Conium maculatum (poison hemlock) within the crop, proventriculus, and gizzard. Histopathologic alterations were limited to catarrhal enteritis. Clinical signs of Conium maculatum toxicosis abated after the turkeys were removed from their range, which was infested with poison hemlock.     

Optimization of the metham-sodium dose in controllingVerticillium dahliae in potato

In fields naturally infested withVerticillium dahliae, metham-sodium at 400, 600 and 800 1/ha was applied to reduce the fungal population. Metham-sodium delayed and reduced disease incidence at all doses tested compared with the control; this effect was maximal at 800 1/ha. However, an optimal yield (maximum kg potato/liter metham-sodium) was obtained at 600 1/ha.     

Cost-benefit analysis and investment appraisal in relation to pest control measures

A distinction is drawn between cost-benefit analysis and investment appraisal. Both are methods for evaluating projects, with cost-benefit analysis looking at proposals from the angle of the larger community in contrast to investment appraisal which looks at them from the individual, or firm, point of view. The time value of money is examined and also the treatment by cost-benefit analysis of social values and other elements outside the purview of investment appraisal, the so-called externalities or spillovers. Cost-benefit analysis of pest control measures is shown to depend heavily on analysis of the complexities and interactions of the biological/biochemical systems involved. This leads to the conclusion that the main thrust of cost-benefit studies in the pesticide field is to improve our understanding of pest problems and thereby to improve the efficiency of pest control measures, to the benefit of both the industry and the public.