The head-related transfer function (HRTF) is dependent on the position of the sound source (both direction and distance) and is also affected by individual anatomical parameters. Individualized HRTFs have been shown to affect the perception of sound direction, but have not been considered in distance perception. This work aims to discover, by means of psychoacoustic experiments for a virtual reproduction system through a pair of in-ear headphones, the effect of individualized HRTF on auditory distance perception for a nearby sound source. The individualized HRTFs of six subjects and the non-individualized HRTFs of a mannequin at seven distances between 0.2 and 1.0 m and five lateral azimuths between 45X and 135X in the horizontal plane were processed with white noise to generate binaural signals. Further, the individualized and non-individualized HRTFs were used in the auditory distance perception experiments. Results of distance perception show that the variance of distance perception results among subjects is significant, the reason could be the stimuli are lack of dynamic cue and early reflections, or the auditory difference of distance perception among subjects. However, via the analyses of mean slope of perceptual distance and correlation between the perceptual and real distance, we find that the individualized HRTF cue has insignificant influence on distance perception.
The aim of this study was to determine to what extent the ions present in hard water (125 mg/L of MgCl2 and 500 mg/L of CaCl2) may intensify the feed-induced decrease in oxytetracycline (OTC) absorption rate in broiler chickens after single oral administration at a dose of 15 mg/kg. Drug concentrations in plasma were determined by liquid chromatography-tandem mass spectrometry and combined, compartmental and non-compartmental approach was used to assess OTC pharmacokinetics.
The administration of feed decreased the absolute bioavailability (F) of OTC from 12.70%±4.01 to 6.40%±1.08, and this effect was more pronounced after the combined administration of OTC with feed and hard water (5.31%±0.90). A decrease in the area under the concentration- time curve (AUC0-t), (from 10.18±3.24 μg·h/ml in control to 5.13 μg·h/ml±1.26 for feed and 4.26 μg·h/ml±1.10 for feed and hard water) and the maximum plasma concentration of OTC (Cmax) (from 1.22±0.18 μg/ml in control, to 1.01 μg/ml ±0.10 for hard water, 0.68 μg/ml±0.10 for feed and 0.61 μg/ml±0.10 for feed and hard water) was observed. The results of this study indicate that feed strongly decreases F, AUC0-t and Cmax of orally administered OTC. The ions present in hard water increase this inhibitory effect, which suggests that, therapy with OTC may require taking into account local water quality and dose modification, particularly when dealing with outbreaks caused by less sensitive microorganisms.
Studies on food preference of herbivores include no-choice test and test with choice or multiple choice. Conclusions from statistic analyses of these tests are compared descriptively. The definition of compatibility index and consumption growth index has enabled us to use nonparametric test for verification of hypotheses about homogeneity of the consumption growths of selected plant species under no-choice and multiple choice conditions. The studies were conducted on food preference of the slug Deroceras reticulatum. It has been found that Chamaenerion angustifolium, Geraniumpusillum and Potentilla anserina can be used to reduce this slug feeding on cultivated plants. It has been also found that seedlings of Polygonum aviculare can be used as alternative food for slugs.