Vol. 12 Issue 1
J. Abdul-Salam and B.S. Sreelatha
A philophthalmid cercaria, Cercaria kuwaitae IV sp. n., is described from the prosobranch gastropod, Cerithidea cingulata (Gmelin 1790) from Kuwait Bay. Details are presented on the morphology and behavior of the cercariae. Scanning electron microscopy was used to study the surface features of the cercariae and daughter rediae. This is the first record of a philophthalmid cercaria from the Arabian Gulf region.
Jumah Shakhanbeh
Mechanical response of the rat C-Polymodal nociceptors (C-PMNs) to repeated controlled forces (10-100 mN) was studied before, during and after acute severe reduction in the blood pressure (hypotension). Von Frey pressure thresholds of these units were not affected by the hypotensive conditions. However, the mechanical response of the C-PMN units to repeated controlled mechanical forces was markedly decreased in 9 units (out of 10 units) during and after hypotension compared to their normal response before hypotension. The reduction in the excitability of the rat C-PMNs to strong mechanical stimulation under the conditions of acute hypotension is probably due to the decrease in the amount of oxygen supply with the subsequent accumulation of metabolites nearby their nerve terminals.
Ahmed S. Babeir and Mohammed F. Wahby
Cultivated land had been multiplied many times in Saudi Arabia in the last decade. Merit thereby was due to the use of agricultural tractors.
The objectives of this study were to determine the distribution pattern of farm tractors among farmers in the country during the period of 1979 to 1990, to determine the power indicator, and to predict the future need for tractor power level and numbers.
Results showed that tractor numbers decreased yearly with an average of 250.4tractors, and the highest number of tractors were distributed in 1983. Tractor average power ranged between 49.7 kW to more than 80 kW with an average yearly increase of 2.58 kW, whereas power indicator ranged from 2.5 kW/ha to 16.6 kW/ha in the different regions of the Kingdom.
This was due to small parcels of farms, as well as, owning more than one tractor by farmer. Power indicator increased yearly with an average of 0.33 at the country level. Recommendations of this study were:
(1) To follow another method for distributing farm tractors depends on average power requirements per unit area for farms.
(2) Tractor average power must not exceed 80kW in the future except for big agricultural projects.
(3) Average number of tractors for next decade will be between 1130 to 1485 per year.