No abstract

Bottom backscatter measurements have been made at six shallow-water sites over the frequency range 20–85 kHz for bottom types including silt, sand, and gravel. Bottom samples were taken at all experimental sites, and some sites are well characterized in terms of seabed acoustic parameters and roughness. A slight frequency dependence was observed, and scattering strength was generally found to decrease as grazing angle decreased. Backscatter measurements in four azimuthal directions showed no measurable anisotropy for grazing angles between 10° and 40°. Spatial variability of backscatter strength was measured along two tracks approximately 35 and 75 km long.

No abstract

An analytical method developed for the determination of total methiocarb residues on grapes included initial extraction with acetonitrile, oxidation of residues to methiocarb sulfone with m-chloroperbenzoic acid, derivatization with methanesulfonyl chloride, and quantitation by sulfur pecific flame photometric gas chromatography. Grape juice, pomace, and wine were analyzed to determine the fate of methiocarb during vinification. Samples were also analyzed for the individual metabolites of methiocarb by using similar methods but omitting the oxidation step. Total residue on Pinot noir grapes treated 4 times at 4.5 kg /ha was 46 ppm 7 days after a handgun application and 7.4 ppm if the material was applied by airplane. Residues on White Riesling grapes treated with a concentrate sprayer at the same rate ranged from 12 to 19 ppm 7 days after last application. About 50-80% of the residue on fruit was removed from the vinification process with pomace and additional reductions occurred during the settling of juice. Total residue in wines made from grapes treated 7 days before harvest was 4.9 ppm in White Riesling wine and 4.6 ppm in Pinot noir wine which represented 26 and 13% of the initial residue on grapes.

SYNOPSIS A method has been described for the estimation of calcium and magnesium in serum and urine using atomic absorption spectrophotometry. The precision and accuracy of the techniques have been determined and were found to be acceptable.The range of values for calcium and magnesium in the sera of normal adults was found to be: serum calcium (corrected to a specific gravity of 1 026) 8 38-10 08 mg. per 100 ml.; serum magnesium 1.83-2-43 mg. per 100 ml.A wide variety of methods has been used for the estimation of calcium and magnesium in biological fluids. Among the more recent, the technique employing the principle of atomic absorption spectroscopy appears to offer a relatively specific method, and one in which interference from other factors can be reduced to a mininum.The apparatus employed in this laboratory is a Techtron atomic absorption spectrophotometer model A.A.3, manufactured