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SUMMARYA total of 495 calves in 16 batches were examined (117 calves in 4 batches in 1979 and 378 in 12 batches in 1982). They were purchased in markets, transported by road to a farm in Somerset and reared on a milk substitute diet for a period of up to five weeks. Salmonella typhimurium phage type DT 193 was endemic in 1979 and phage type DT 204c in 1982. The mortality rates in the two years were 9S4 % and 1-9% respectively. The causes of death were not investigated although the majority were probably due to salmonellosis.The rate of isolation of S. typhimurium from the rectal faeces of calves in all groups was either zero or relatively low on arrival. It rose to a peak (which was higher in 1979) in the second or third weeks before declining to low levels by the end of the fourth week of residence on the farm.Data from 162 calves, examined twice weekly for four weeks in 1982, indicated that the distribution of infected calves, based on the number of times that S. typhimurium was isolated from each, was not random. The calves could be assigned to two main categories; those from which the organism was never isolated and those from which it was isolated at least twice. This suggested that salmonella infected calves actively excreted the organism.The association between salmonella excretion and medication of sick animals with antibacterial drugs was strongest during the second week. Over the four-week period nearly 40 % of the calves found to be excreting S. typhimurium were not treated, indicating a high incidence of subelinical infection.Salmonella excretion by the calves followed a regular pattern and infection was self-limiting within five weeks. The peak in the salmonella excretion rate and the mortality rate were higher in 1979 when phage type DT 193 was the endemic strain. However, in 1982 the calves received 100 p.p.m. furazolidone in their milk ration during the first week of their stay on the farm, and this may have contributed to the differences noted between the two years.

seasons to study the effect of preceding crop, rates and splitting of nitrogen fertilizer on bread wheat production and nitrogen use efficiency. The experiment was carried out in randomization complete block design (RCBD) using splitsplit plot arrangement with three replications. Cropping system (corn-clover-wheat and corn-fallow-wheat) were assigned in main-plots while nitrogen fertilizer rates (56.25, 75.00 and 93.75 kg N/fed) were allotted in sub-plots and splitting doses of nitrogen (two, three and four equal doses) were allocated in sub-sub plots. The obtained data showed that plant height, spike length, number of spikes/m 2 , number of grains/spike, weight of grains/spike, seed index, grain yield, straw yield and nitrogen use efficiency were significantly affected by cropping sequence in favor of planting wheat after clover (fahl berseem) in the two growing seasons except nitrogen use efficiency in the first season. Increasing nitrogen fertilizer rates resulted in significant increase in all previous traits except nitrogen use efficiency trait which was decreased by increasing nitrogen fertilizer rates in both seasons. Moreover, splitting nitrogen rates into four equal doses significantly increased all studied traits as compared to three or two equal splits in the two growing seasons. Also, all interactions had a significant effect on all studied traits in both seasons. The highest mean values of grain yield (27.47 and 28.22 ard/fed in the first and second seasons, respectively) were obtained from the sequence of corn-clover-wheat when received highest nitrogen rate (93.75 kg N/fed) which was applied at four equal doses.

designed BPF are as follows: W 1 5 1.5 mm, W 2 5 1.0 mm, W 3 5 0.6 mm, W 4 5 1.0 mm, W 5 5 0.88 mm, L 1 5 5.7 mm, L 2 5 5.88 mm, L 3 5 9.23 mm, L 4 5 11.0 mm, L 5 5 12.0 mm, L 6 5 3.51 mm, d 1 5 0.17 mm, d 2 5 0.17 mm, d 3 5 0.17 mm, and d 4 5 0.17 mm.ABSTRACT: In this article, an ultrawideband (UWB) antenna with triple band-rejection characteristics is proposed. The antenna is compact with size of 22.5 3 24 mm 2 . Matching between a sector-disk shaped radiating patch and the 50-X microstrip line is manipulated through a proximity-feed technique. An elliptically-shaped aperture is etched in the ground plane to enhance the antenna bandwidth. Double shunt stubs are used to get more enhancement of the impedance bandwidth of the