Vol. 12 Issue 3
Mahmoud A. El Banhawy, Mohamed F. El-Asmar, Fathalla M. Hassan and Tarek R. Rahm
The effects of an intramuscular injection of the sublethal dose of the venom of the non-horned Cerastes cerastes snaks, as well as its purified hemorrhagic toxin "HR-a", on some cellular components of the liver cells of mice were histochemically demonstrated. After 24 h. of injection , depletion of polysaccharide and fat contents were observed in the hepatic cells of mice injected with the hemorrhagic fraction, whereas no changes were recorded in sections obtained from venom-treated animals. On the other hand, depletion of RNA contents was induced in cells of venom-injected animals, but no changes in such contents were detected in cells of HR-a injected animals. The hepatic cell's nuclei were mostly negative for DNA reaction in materials obtained from envenomated mice. However, margination of DNA was prominent due to the injection of the hemorrhagic toxin. A severe degree of protein depletion was also detected in the hepatocytes post-injection with either the venom or the hemorrhagic toxin.
Wafica, M. Aboul Naga
The concentration of humic substances as humic and fulvic acids in Lake Edku sediment cores accounts for 54% of the total organic carbon in the three cores sediment samples. The total average trace metal concentrations of Fe, Mn, Zn, Cu, Pb and Cd are 55150, 1019,79, 52,42 and 3.5ug g-1, respectively in sediment core samples. The most abundant metals present in the humic acids were Fe, Zn, Cu, Pb, Mn and Cd. Significant portions of the total Pb, Cu and Zn found in the sediments were associated with humic acids. Smaller portions of Cd was found, whereas insignificant fractions of the total sedimentary Fe and Mn were recovered in association with humic acids. It is of interest to mention that while the total humic carbon represents only 29.5% of the total organic carbon, the humic acids contribute about 83% of lead and 75% of copper. These results reflect the importance of humic acids as a sink for these metals in lake sediment cores.
Abdullah M. Alshamsi
This paper examines the efficiency of the use of set-retarding superplasticizers in concrete and cement mixes for the purpose of reducing water content. Water-cement ratio was reduced from 0.6 to O.S for the concrete mixes and from 0.27 to 0.205 for cement pastes. Five different tests were performed: setting times, workability, compressive strength, porosity and water absorption. With the exception of workability batches, all samples were cured at 20°C, 35°C and 50°C. Three different curing regimes were employed; air curing, 3-day water curing and continuous water curing. Workability was measured both indoors (20°C + 65% RH) and or outdoors (38°C + 50% RH). Results indicate that high temperatures accelerate setting, workability loss and strength development but 28-day strength results were lower when compared to normal temperatures. The inclusion of superplasticizers improved the hardened concrete properties due to the lower wlc ratio but these improvements were smaller at high temperatures.
Eissa, A.M., Shehab El-Din, T.M. and Dawood, A.M
The present investigation was carried out during the 1990/91 and 1991/92 seasons to determine the optimum planting date for maximizing wheat production under AI-Qassim conditions. The experiments were conducted at the Agricultural experimental Station, College of Agriculture and Veterinary Medicine, King Saud University, Al-Qassim Branch, Saudi Arabia. Two high - yielding spring wheat cultivars; Yecora Rojo and West Bread, were planted in six dates; November 16, December 1 and 16, January 1 and 16 and February 1. The experiments were set up in a split plot design with four replications. Results revealed that planting dates had significant effects on all studied traits. Significant cultivar x planting date, planting date x season and cultivar x planting date x season interactions existed for grain yield and its components, plant height and days to heading. The best planting date for Yecora Rojo cultivar was January 1st and for West Bread cultivar was December 16 in the first season while the first of December was the best planting date for both cultivars in the second season for maximizing grain yield. Spikes per square meter and kernels per spike significantly increased while kernel weight non-significantly decreased as planting date was delayed from November to December. It could be concluded that the optimum period for planting date in Al-Qassim region lies within the first two weeks of December. Expanding planting to January 1st could be possible, while planting after this period would result in yield reduction.
Mohammed O. Ghandorah and Yahya A. Refay
This study was carried out to evaluate four sugar beet cultivars grown at four different sowing dates at Deirab Agricultural Experimental Station, College of Agriculture , King Saud University during the winter of 1990 and 1991.
The results indicated that top yield, biological yield , total soluble solids (TSS), reducing sugars (RS) and non-reducing sugars (NRS) differed significantly among seasons and cultivars. In addition, there were significant differences between sowing dates with regard to all characters studied. Highly significant positive correlations were found between root yield and top yield and between biological yield , and root and top yield. A highly significant negative correlation was also found between the average weight of root and TSS.
Statistical analyses indicated that there were no important significant interactions for cultivars x seasons, cultivars x sowing date and cultivar x sowing date x seasons, indicating the stability of the four cultivars under different environments.
It could be concluded that the period from October 15 to November 1 was the most suitable period for sowing sugar beet in the Central Region of Saudi Arabia.
Shahina A. Ghazanfar and Dieter Rappenhöner
The vegetation of the Islands of Masirah and Shaghaf is broadly classified with that of Barr al Hikman (east-central Oman) and its adjacent areas. The detailed study shows 8 vegetation types which are related to the different landforms of the Islands. The highest number of species are recorded in the central mountain range in Masirah and the highest number of halophytes known from Shaghaf Wadis are identified as the most species-rich areas. Stipagrostis masirahensis and Euphorbia masirahensis are endemic Poecilohydric lichens, unknown elsewhere on mainland Oman, are present on limestone outcrops in the north and south of the central mountains in Masirah..
Ahmad K. Hegazy, Magda I. Soliman and Ibrahim A. Mashaly
Heliotropium curassavicum L. (Boraginaceae) has become a serious polycarpic weed infesting many agricultural fields in the newly reclaimed salt affected lands in the Deltaic Mediterranean coast of Egypt. Floristic composition of its plant communities, seed germination, phytomass allocation, adventitious root buds, cell division and karyotype analysis, and pollen fertility were investigated. The following results were obtained:
(1) The poor adaptation of its associated wild plants and the strong selection pressure in the Deltaic agro-ecosystems supported the dominance of H. curassavicum as a weed.
(2) Persistence of intermittent seed germination and seedling establishment in open areas increases the chance of its spreading.
(3) Synchronized pattern of dry phytomass allocation and phenological events through different stages of the life cycle.
(4) Ability to produce adventitious root buds allow for the plant's perennation and wide spreading.
(5) Chromosomal abnormalities during the cell division included lagging chromosomes, chromatin bridge, stickiness, mis-orientation and asynchrony. These abnormalities and the reduced pollen fertility made the species shifts its sexual reproduction to vegetative propagation by adventitious root buds.
A. A. Salamah
Yersinia enterocolitica and Yersinia pseudotuberculosis were isolated from 83 (20.4%) out of 406 rodents and from 64 (8.8%) out of 725 cat feces samples. The isolates from rodents include 59 Y. enterocolitica and 24 Y. pseudotuberculosis, whereas, the isolates from cat feces include 19 Y. enterocolitica and 45 Y. pseudotuberculosis. The rates of virulent Y. enterocolitica and Y. pseudotuberculosis in rodent isolates were found to be 10.2% and 79.2% respectively, whereas, for cat fecal isolates these rates were 42.1% and 86.7%, respectively. The highest incidence of the two species in both cat feces and rodents occurred in the cold months.
Said M. Al-Ghais and M. M. Kardousha
A total of 610 fish belonging to 4 species collected from both west and east coasts of U.A.E. during the period from September 1991 to May 1992 were investigated for the presence of helminth parasites larvae. The fish were Argyrops spinifer, Lethrinus miniatus, Lutjanus fulviflamma and Nemipterus japonicus. Two common types of larvae were detected, the nematode Anisakim sp. type I larvae and the cestode plerocercoid Floriceps sp. When a comparison was made between the west and east coasts the total prevalence of helminth infection in the fish species, found on the east coast (42.7%), was markedly higher than that noted on the west coast (29.4%)
Mohammed S. Al-Khalifa and Mohammed I. Siddiqui
The glycogen content of the haemocytes of the ixodid ticks, Hyalomma dromedarii and hyalomma arabica was investigated in males, females and nymphs of both tick species. Granular haemocytes, plasmatocytes and spherulocytes have a large glycogen content, but the oenocytoids and adipo haemocytes have very few glycogen granules, while the pro haemocytes are devoid of glycogen. All haemocytes of unfed ticks of both species, with the exception of granular haemocytes lacked glycogen granules. The glycogen granule counts of the haemocytes of fed female ticks of both species were much larger than those of fed male ticks. The role of glycogen synthesisand its utilization is discussed.