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Table of Contents Abstract Case History Discussion References Abstract In contrast to squamous cell carcinoma of the penis, scrotal carcinoma has historically been a disease of chimney sweeps, associated with [...]

A simulation model of a time-sharing system with a finite noncontiguous store and an infinite auxiliary store is used to study the variation of system parameters such as store size, number of jobs allowed to execute simultaneously, job-scheduling algorithm, etc. The effects of these variations on a measure of system performance is used to ascertain which of the parameters controllable by the job-scheduling algorithm, including the scheduling itself, require optimization, and which of the parameters not normally controllable by the scheduling algorithm have a marked effect on system performance. System performance is based upon the mean cost of delay to all jobs processed. It is shown that significant improvements in the measure of system performance can be obtained by using variable time-slice techniques and by selecting the optimum round-robin cycle time. It appears that these features would benefit from optimization whereas other parameters controllable by the scheduling algorithm affect system performance in a predictable manner and would not benefit from optimization. Features not normally under the control of the scheduling algorithm can also have a marked effect on the measure of performance; in particular, supervisor overheads, the size of the store, and the speed of the CPU. A comparison is made between the results of the simulation model and two analytical equations for quantum-oriented nonpreemptive time-sharing systems. The comparison is found to be very favorable. [ABSTRACT FROM AUTHOR]

The levels of antigen-specific antibodies (Abs) and immunoglobulins in the cervical mucus of women vary with the menstrual cycle; the highest levels occur during menses, and the lowest occur during the periovulatory period. The rhesus macaque is a widely used animal model of female genital tract immunity. We sought to determine whether rhesus macaques have a cyclical pattern of changing cervicovaginal Ab and immunoglobulin levels that is similar to that of the human female. This study examined the relationship of the stages of the menstrual cycle to genital mucosal and systemic immunoglobulin concentrations and Ab levels in rhesus macaques. In all seven rhesus macaques studied, the immunoglobulins G and A and some antibodies in cervicovaginal lavages varied with the stages of the menstrual cycle, and in many cases this variation reached the level of statistical significance. In a pattern similar to that of women, the highest levels of Abs and immunoglobulins occurred during menses, and the lowest levels occurred around the time of ovulation. However, the Ab and immunoglobulin levels in serum and rectal lavages did not change with the menstrual cycle stage. The results of this study are consistent with the hypothesis that the ovarian hormones that drive the menstrual cycle influence genital tract immunity in female primates.

A total of 56 steers and heifers (28 purebred Chianina [late maturing] and 28 Hereford × Angus crossbred [early maturing]) were allotted to a 2 (breed-type) × 2 (sex class) × 4 (days on feed) factorial arrangement. Eight cattle (four late maturing and four early maturing) were slaughtered 1 d after allotment; the remaining 48 cattle were fed a high-concentrate diet for either 77, 128 or 182 d. Adjusted fat thickness, percentage of shankless round fat and percentage of carcass fat from early maturing (EM) cattle increased (P< .05) over days on feed (1.5 to 19.9 mm, 5.3 to 21.0% and 12.0 to 36.1%). These fatness measures on the carcasses of late maturing (LM) cattle increased (P< .05) up to 77 d then generally stabil- ized. A breed × days on feed (DOF) interaction (P< .05) resulted from yield grades increasing over time for EM carcasses (1.6 to 3.7), but yield grade for LM carcasses did not vary across DOF (1.5 to 1.3). Muscle to bone ratios (M:B) for the round were higher (P< .05) for EM carcasses than for LM carcasses (6.3 vs 5.6). USDA quality grades increased (P< .05) for both breed groups, but they increased at a faster rate for the carcasses from the EM breed-type. A breed × DOF (cubic) interaction (P< .05) occurred for tenderness, which resulted from loin steaks from LM carcasses that were “very tender” with 0 DOF and became “slightly tender” with any level of grain feeding. The loin steaks from EM carcasses were “slightly tough” with 0 DOF and became “moderately tender” with grain feeding. The later maturing cattle produced carcasses with about 50% less fat, 2 to 10% more saleable product and lower M:B ratios and USDA quality grades than the earlier maturing cattle. Results indicate that low-fat beef with desirable palatability could be produced by cattle of a late maturing breed-type.