Retention of Selenium in Kidneys,Liver and Striated Muscle After Prolonged Feeding of Therapeutic Amounts of Sodium Selenite to Pigs

Sodium selenite was mixed in a commercial pig food so as to increase the original selenium content (0.126 ppm) by 1.2 ppm. The supplemented food was given to 7 pigs during 78 days. A control group of as many pigs was given the non-supplemented commercial food. The pigs were killed, starting 4 hours after the last selenium-supplemented food had been given and then with intervals during the next 14 days. Small but significant increases of tissue selenium were noticed in liver and striated muscle as compared with the control animals. The kidneys showed no increase.     

STUDIES ON WEED SPECIES OF THE GENUS POLYGONUM L.

Summary. Seeds of Polygonam persiaria were collected from seven localities during 1962. In 1963 plants of these seven populations were grown in the field and sampled at regular intervals over the period 21st June to 13th August. At all samplings there were differences between populations in total dry weight, in leaf area index and in total nitrogen content, and populations also differed in the date of flowering. The populations also differed significantly in relative growth rate, leaf area ratio, net assimilation rate and relative nitrogen absorption rate. The variations in net assimilation rate did not appear to be closely associated with variations in leaf area index. Certain growth attributes were correlated with the latitude of origin, and it is tentatively suggested that the populations may represent genetically distinct latitudinal ecotypes.
Études sur des espèces de mauvaises herbes du genre Polygonum L.     

Giant radiation-induced color halos in quartz: solution to a riddle

The radii of radiation-induced color halos(RICHs) surrounding radioactive mineral inclusions in mica generally correspond closely to the calculated range of common uranogenic and thorogenic alpha particles in mica. Many exceptions are known, however, and these variants have led investigators to some rather exotic interpretations. Three RICHs found in quartz are identified as aluminum hole-trapping centers. Whereas the inner radii of these RICHs closely match the predicted range of the most energetic common alphas(39 micrometers), the color centers observed extend to 100 micrometers. Migration of valence-band holes down a radiation-induced charge potential might account for enigmatic RICHs. Such RICHs provide natural experiments in ultraslow charge diffusion.     

Alleviation of postanesthetic hypoxemia in the horse

This study was designed to investigate the effect of the nasotracheal insufflation of oxygen at a flow rate of 15 L/min on the arterial partial pressure of oxygen during the recovery period following inhalation anesthesia in the horse. It has been stated that this is a suitable flow rate to prevent postoperative hypoxemia but without any experimental evidence to support those statements. Horses being used for the study of healing of cartilage were anesthetized on two separate occasions. Following one period of anesthesia they were allowed to recover breathing room air, and following the other period of anesthesia oxygen was insufflated into the trachea at 15 L/min throughout the recovery period. This permitted each horse to act as its own control and allowed statistical analysis using Student's t-test for paired samples.

The insufflated horses had a higher arterial partial pressure of oxygen during the recovery period than did the noninsufflated horses (p < 0.05).

     

The detection and measurement of stray electrical leakages on dairy farms: effects on performance

Sources of stray electrical leakage from Power Supply Authority alternating current (AC), fence energiser pulses and randomly generated pulses and spikes on 55 dairy farms in the Waikato area were identified between December 1986 and March 1988. The electrical measurements were made using a specifically designed voltmeter able to detect voltages between 0.1V and 1500V, from single voltage spikes of two microseconds or greater duration from direct current (DC) as well as 50 Hz AC. Ninety-five sources of stray voltage were identified, and 53 per cent of properties had more than one source of >0.5V. The major source was from electric fence energisers. Rotary platform parlours were among the commonest sources of random or transient voltage spikes. Leakage of AC into one or other of the components of the milk transport system such as vat, plate cooler, milk lift pump and milk line was common. Owners acknowledged the improvements in milk production, reproductive performance and growth rate of calves after reduction of the exposure of dairy cattle to stray electrical leakage. A representative summary of five case records helps define the range of improvements that may possibly be achieved.