Oral Interview of Rolf Slen

https://red.mnstate.edu/oral_interviews/1330/thumbnail.jp

Study of Damage Propagation at the Interface Localization-Delocalization Transition of the Confined Ising Model

The propagation of damage in a confined magnetic Ising film, with short range competing magnetic fields ($h$) acting at opposite walls, is studied by means of Monte Carlo simulations. Due to the presence of the fields, the film undergoes a wetting transition at a well defined critical temperature $T_w(h)$. In fact, the competing fields causes the occurrence of an interface between magnetic domains of different orientation. For $T T_w(h)$) such interface is bounded (unbounded) to the walls, while right at $T_w(h)$ the interface is essentially located at the center of the film. It is found that the spatio-temporal spreading of the damage becomes considerably enhanced by the presence of the interface, which act as a ''catalyst'' of the damage causing an enhancement of the total damaged area. The critical points for damage spreading are evaluated by extrapolation to the thermodynamic limit using a finite-size scaling approach. Furthermore, the wetting transition effectively shifts the location of the damage spreading critical points, as compared with the well known critical temperature of the order-disorder transition characteristic of the Ising model. Such a critical points are found to be placed within the non-wet phase.Comment: 22 pages, 13 figures include

EFFECT OF ESTRADIOL AND TESTOSTERONE INJECTIONS AND THYROIDECTOMY ON WOOL GROWTH IN SHEARLING SHEEP

An experiment was conducted to determine the effect of relatively high doses of estradiol and testosterone, with and without thyroidectomy, on clean wool production and certain endocrine glands of shearling sheep. The administration of 5 milligrams of estradiol intramuscularly at biweekly intervals to sheep with thyroids caused a reduction in the average weight of clean wool (p &lt;.05) and fibre length (p &lt;.01). This treatment produced increases (p &lt;.01) in thyroid, pituitary, and adrenal weights. The administration of estradiol to thyroidectomized ewes reduced the weight of clean wool (p &lt; 05) when compared with the thyroidectomized controls but no such response was observed in wethers. Testosterone administered at levels of 175 milligrams bi-weekly produced no effect on weights of clean wool, in ewes or wethers, but when it was administered to thyroidectomized animals average fibre lengths were decreased (p &lt;.05). </jats:p

WOOL PRODUCTION OF RANGE EWES AT THREE INTENSITIES OF GRAZING

Mature, white-faced ewes grazed mixed prairie range at the rate of 1.7, 2.0, and 2.5 ha per animal unit month (AUM) for 9 months annually over an 18-year period at the Canada Agriculture Research Substation, Manyberries, Alberta. As intensity of grazing decreased, production of raw and clean wool and body weight at shearing increased significantly. The average regressions of fleece weight on body weight at shearing were 0.034, 0.031, and 0.026 kg of raw fleece and 0.024, 0.020, and 0.018 kg of clean fleece for ewes on the heavy, moderate, and light rates of grazing, respectively. There were no differences in the wool characteristics measured or in body weight at shearing of two subgroups of ewes, one receiving phosphorus supplement and salt and another salt alone, when alfalfa hay was fed during 3 winter months. To obtain maximum production of wool per ewe, the stocking rate should be set at not less than 2.0 ha per AUM. </jats:p

THE INFLUENCE OF PROTEIN AND ENERGY CONTENT OF THE RATION ON LAMB AND WOOL PRODUCTION OF RANGE EWES

Two feeding experiments were carried out with range ewes to determine the influence of the protein and energy content of the ration on lamb and wool production. When the energy content of the ration was increased approximately 10 per cent during early pregnancy [digestible crude protein (D.C.P.) intake was approximately 0.14 pound and digestible energy intake was approximately 3.2 therms daily on the basal ration], body weight gains and wool production of the ewes were increased (P &lt; 0.05 and P &lt; 0.01, respectively), but birth weights of the lambs in one experiment and 6-week weights of the lambs in both experiments were not affected significantly. However, when the energy content of the ration was increased during late pregnancy and early lactation (D.C.P. intake between 0.12 and 0.24 pound and digestible energy intake approximately 3.7 therms in Experiment 1, and 2.7 therms in Experiment 2, daily on the basal ration), body weight gains of the ewes were not affected, wool production was depressed (not significant in all cases), birth and 6-week weights of single lambs and birth weights of twin lambs in Experiment 1 were not affected. In Experiment 2, increasing the energy content of the ration reduced (P &lt; 0.05) the birth weights of twin lambs.When the protein content of the rations was increased (from 0.16 to 0.20 to 0.24, and from 0.12 to 0.14 to 0.16 pound D.C.P. intake daily in Experiments 1 and 2, respectively), there was no increase in body weights of the ewes or birth weights of single lambs, but there was an increase (P &lt; 0.05) in the birth weights of twin lambs and an increase (P &lt; 0.01) in wool production of the ewes. Increasing the protein content of the rations increased the 6-week weights of single and twin lambs in Experiments 1 and 2 (P &lt; 0.05). The results of these experiments suggest that the minimum average protein requirement for pregnant and lactating ewes was approximately 0.10 and 0.11 pound D.C.P. per pound of T.D.N. intake for maximum lamb and wool production, respectively.A nitrogen-balance and wool-growth study using non-pregnant, mature ewes showed that increasing the energy intake at low levels of protein intake caused a reduction in the apparent but not the "true" digestibility of the protein, no change in the biological value of the protein, and a reduction in weight of clean wool produced. At a higher level of protein intake, an increase in energy content of the ration resulted in no change in the apparent or true digestibility of protein but in an increase in wool production. </jats:p