Percolation of core melts at lower mantle conditions

Experiments at high pressure and temperature to determine the dihedral angle of core melts in lower mantle phases yielded a value of approximately 71 degrees for perovskite-dominated matrices. This angle, although greater than the 60 degrees required for completely efficient percolation, is considerably less than the angles observed in mineral matrices at upper mantle pressure-temperature conditions in experiments. In other words, molten iron alloy can flow much more easily in lower mantle mineralogies than in upper mantle mineralogies. Accordingly, although segregation of core material by melt percolation is probably not feasible in the upper mantle, core formation by percolation may be possible in the lower mantle.     

Effects of age on the electroencephalographic response to castration in lambs anaesthetised using halothane in oxygen

AIM: To use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex to the noxious stimulus of castration varied with age in lambs.

METHODS: Two groups of East Friesian lambs were selected according to age; the mean age of the younger group (n=21) was 12 (SD 2) days and the older group (n=20) was 29 (SD 1) days. Anaesthesia was induced via mask using 4% halothane in oxygen, and maintained using 1.5% halothane in oxygen at a flow rate of 4 L/min. Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiographic (ECG) readings commenced, and the lambs were castrated 15 min later, using rubber rings. Median and 95% spectral edge frequencies (F95) and total EEG power (ptot) were derived from data from the EEG.

RESULTS: Following castration, there was an increase in the median frequency (F50) in the younger lambs (p=0.002), and an increase in ptot in both groups (p=0.05), which was of greater magnitude in the older lambs. There were no significant changes in the F95. Both younger and older lambs exhibited a transient bradycardia (p=0.001 and p=0.01, respectively).

CONCLUSIONS: These differences in the cortical response between the two groups suggest that 2-week-old lambs undergo a qualitatively different perception of the noxious stimulus of castration compared to 4-week-old lambs.     

Quantitative determination of flesh mealiness in peach [Prunus persica L. (Batch.)] through paper absorption of free juice

A simple and rapid method was developed for quantitative determination of juiciness in peach flesh based on the absorption of free juice with ordinary absorbent paper after a flesh sample is squeezed by two metallic rolling cylinders. Juiciness data were compared with trained panel determinations on three peach cultivars kept at 4 °C and 90% RH for 7, 14 and 21 d plus a ripening period at 20 °C and 65% RH until the flesh reached 19.6 ± 9.2 N. There was a high correlation between panel judgment and paper absorption (r² = 0.75 in ‘Elegant Lady’, 0.77 in ‘O’Henry’ and 0.93 in ‘Ross’). A sub-sample of the juiciest and the mealiest fruit also were sorted after 14 and 21 d in cold storage. ‘Ross’, a non-melting peach cultivar, did not develop flesh mealiness during any evaluation period. During storage, there was a reduction in juiciness reaching 15% less after 21 d. Mealy fruit were exclusively observed with melting cultivars exposed to cold storage. The proposed method for determining juice content is easily executed and shows a high association with human perception of juiciness and mealiness in peach.     

Origin of the equine middle latency auditory evoked potential

Recordings of the middle latency of the auditory evoked potential (MLAEP) were made in eight conscious ponies. These traces were compared to those made under halothane anaesthesia with and without paralysis of the skeletal muscles. Recordings were also made from percutaneous electrodes placed along the neck with the same stimulus used for the auditory evoked potentials. The results of these experiments were used to deduce the origin of latencies in the auditory evoked potential occurring between 10 and 25 ms after the stimulus. The MLAEP was found to contain two positive peaks between the latencies of 10 and 25 ms. The first of these two peaks was not abolished by halothane anaesthesia or muscle paralysis. The second of these two peaks was abolished by halothane anaesthesia in all but one animal. In this animal the second peak was abolished by muscle paralysis. No peaks of corresponding latency were recorded from the percutaneous electrodes except from one electrode position at the caudal neck in one pony. The first peak of the middle latency auditory evoked potential seen in conscious ponies appeared to be of central nervous orign. The second peak appeared to be of muscular origin, possibly from the external auditory muscles. The second peak may be analogous to the post-auricular waveform described in man.     

Anticoccidial efficacy of diclazuril against recent field isolates of Eimeria from turkey farms in the United States.

In a series of laboratory tests, diclazuril was evaluated for efficacy against Eimeria adenoeides, E. meleagrimitis, E. gallopavonis, and a mixture of the three species. Four isolates of each of the species were tested. When given at 0.5, 1.0, and 1.5 ppm in the feed, diclazuril was highly efficacious against all three species and against mixtures of the three, as judged by protection against mortality from coccidiosis, reduction in droppings scores, and improvement of weight gains compared with unmedicated controls. When diclazuril was given at 1.0 ppm, the improvement in droppings scores and weight gains was better than when 0.5 ppm of diclazuril was given. Increasing the dosage to 1.5 ppm did not appear to offer any consistent or significant improvement over 1.0 ppm.