Biomedical subjects
Publications and source records attributed to S Nelms.
Ulcerative keratitis is one of the most common vision-threatening diseases of the horse. Successful therapy, however, can be achieved in the majority of cases provided the diagnosis is made early and the treatment is specific for the disease. This article reviews the pathophysiology, clinical signs, and contemporary medical and surgical approaches to bacterial and fungal ulcerative keratitis in the horse.
The modification of subjects' attention by two prosodic features was investigated using their reaction times to a nonspeech stimulus which coincided with these features. By using a foreign language unfamiliar to the subjects (Czechoslovakian), the influence of semantic and syntactic knowledge was controlled. The results indicate that for native speakers of English intonation fall is a relatively more important cue to the perceptual segmentation of speech than is pause.
The performance of four commercially available ICPMS instruments of three different types was compared by means of uranium "isotopic measurements". Examined were two quadrupole sector (different generation, different manufacturer), one single detector double focusing magnetic sector and one multiple collector double focusing magnetic sector instruments. The same samples of the IRMM-072 series were used under routine conditions to measure the 233U/235U and the 233U/238U ratios which, in these samples, vary over almost three orders of magnitude from approximately 1 to approximately 2 x 10(-3). Within expanded (k = 2) uncertainties, good agreement was observed between the certified values and the data internally corrected for mass-discrimination effects. The magnitude of the evaluated uncertainties was different for each type of instrument. With the multiple collector instrument, expanded uncertainties varied from +/- 0.04% to +/- 0.24% for the 233U/235U ratio, and from +/- 0.08% to +/- 0.27% for the 233U/238U ratio. They were approximately 1 to 5 times larger with the single detector magnetic sector instrument, and approximately 10 to 25 times larger with both quadrupole sector instruments. With the multiple collector instrument, repeatability of the measurements seemed to be limited by the difficulty of correcting properly for instrumental background, whereas with the single detector magnetic sector instrument the counting statistics was the only limitation (on smallest ratios). Apparent mass-discrimination was clearly found to be larger but more reproducible (and hence easier to correct for) in the case of magnetic sector instruments than for both quadrupole sector instruments. If space charge effects were the main source of mass-discrimination for all instruments, these results are in contradiction with the hypothesis of the size of mass-discrimination decreasing with the acceleration voltage. With the single detector magnetic sector instrument in particular (when operated by changing the ion energy only), our results pointed at more than only one major source of mass-discrimination, with variable size depending on the ratios measured.