Raman Scattering In Hydrogen Halide Gases

We have measured the Q branch vibrational Raman cross sections of the hydrogen halide gases HCl, HBr, and HI relative to that of N2. We also measured the variation of the HI cross section as a function of the incident laser frequency. The absence of preresonance behavior in HI suggests that the virtual states primarily responsible for Raman scattering lie near or above the ionization potential. This in turn implies that the variation of the Raman cross section among the hydrogen halide molecules results primarily from a variation in the magnitude of the dipole matrix elements rather than from a variation in the energy of the virtual states involved. Copyright © 1975 American Institute of Physics.6393996400

Prevalence of Escherichia coli O157:H7 in cow-calf herds in Kansas

Fecal samples from cows and calves and samples of water sources were collected monthly for 8 months from 10 Kansas cow-calf farms to determine the prevalence of E. coli O157:H7. The bacterium was found in 8% of fecal samples from cows that were within 24 hours of calving, 1.4% of fecal samples from cows which were not within 24 hours of calving, 1.4% of calf fecal samples, and 1.5% of water samples. E. coli O157:H7 was identified from at least one sample on all farms

Expanding the nuclear forensic toolkit: chemical profiling of uranium ore concentrate particles by synchrotron X-ray microanalysis

Nuclear forensic trace evidence may include particles of unknown nuclear or radiological substances which would need to be indentified in an investigation. In this study we report the novel application of synchrotron X-ray microanalysis techniques to characterise the chemistry of particles derived from several uranium ore concentrates (UOCs). Using a combination of micro-focused X-ray diffraction and X-ray absorption spectroscopy, the uranium speciation in particles of 12 UOCs from different geographical sources was identified. Particles were classified based on their composition; four samples were found to contain only U3O8, four samples were comprised of various U(VI) species and the final four were binary mixtures. In addition to U3O8, the identified materials included ammonium, sodium and copper uranate species, and various hydroxide and sulphate phases. Differences in the crystal structure of UOCs which contained the same material were identifiable by μ-XRD, and were hypothesised to be as a result of differences in process conditions. Consistency in particle speciation was assessed in several samples, some of which were found to contain variable levels of two component materials and minor crystalline impurities. Although this variability limits the intrinsic interpretation of single particle microanalysis data in terms of sample provenance, the non-destructive and highly specific analysis of nuclear fuel cycle materials demonstrated in this study will be of value to complex nuclear forensic investigations

Effects of tetracycline on shedding of susceptible and resistant salmonella spp. experimentally inoculated into pigs

The objective of this experiment was to study the influence of tetracycline on the transfer of antibiotic resistance in an in vivo swine model experimentally infected with antibiotic-resistant and antibiotic susceptible Salmonella spp. Tetracycline reduced the amount and duration of shedding of tetracycline- susceptible Salmonella. However, tetracycline had no effect on shedding of resistant Salmonella. We also have evidence that resistance was transferred from the resistant to the susceptible strain of Salmonella

Prevalence of Escherichia coli O157:H7 in cow-calf herds in Kansas

Fecal samples from cows and calves and samples of water sources were collected monthly for 8 months from 10 Kansas cow-calf farms to determine the prevalence of E. coli O157:H7. The bacterium was found in 8% of fecal samples from cows that were within 24 hours of calving, 1.4% of fecal samples from cows which were not within 24 hours of calving, 1.4% of calf fecal samples, and 1.5% of water samples. E. coli O157:H7 was identified from at least one sample on all farms