Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 738-757 of 770
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Trace Metals In Qatari Fish And Shellfish
( Qatar University , 1991 , Article)Fish, prawns and crabs purchased at the retail market in Doha, were analysed for cadmium, chromium, copper, lead and zinc. The results indicated significantly elevated concentrations of cadmium in the flesh of the Qatari ... -
Trace Metals in Wastewater Ponds in Qatar
( Qatar University , 2002 , Article)A one-year monitoring program was conducted to determine the extent of metal contamination in two wastewater ponds in Qatar. Abu-Hamour pond receives untreated domestic and industrial waste while Abu-NakhIa pond receives ... -
Translation - invariant Positive-definite Generalized Kernels of Infinite Number of Variables
( Qatar University , 1981 , Article)In the theory of spectral analysis of positive-definite j<.ernels, there exist well-developed methods based on the ideas of Krein connected with the construction of a Hilbert space by means of a kernel [ 1, 11]. In the ... -
Transmetalation Mechanisms
( Qatar University , 1993 , Article)Transmetalation is the stoichiometric replacement of the metals in a polymetallic target T with different metals from reagents called transmetalators, TM. Transmetalation at useful rates under mild conditions is an excellent ... -
Treptodemus Latus and chauhnotrema spiniacetabulum (tirematoda: digenea); Hemirhamphidae, parasites of the fish, hemirhamphus marginatus from Qatari waters
( Qatar University , 2000 , Article)The fish Hemiramphus marginatus recently examined from Qatari waters was found to be infected with two species of degenetic trematodes: Treptodemus latus Manter, 1961 and Chauhanotrema spiniacetabulum Nahhas ans Sey, 1998. ... -
Triaryl And Trialkyl Phosphites As Corrosion Inhibitors For Copper In Nitric Acid
( Qatar University , 1992 , Article)Some triaryl and trialkyi phosphites were investigated as inhibitors of the corrosion of copper in nitric acid. The values of inhibitor efficiency from weight-loss measurements are in good agreement with those obtained ... -
Two Forms Of The Backlund Transformation Of A Third Order Differential Equation
( Qatar University , 1996 , Article)Two explicit forms of Backlund transformation of third order dispersive differential equation are derived. The method of derivation depends on the use of a transformation that couples the equation with its modified one. -
Two Notes On Modular P-Algebras
( Qatar University , 1988 , Article)According to the definition of congruence .pairs which is given by T. Katrinak, every congruence relation of a modular p-algebra can be uniquely determined by a congruence pair. In the present paper, we characterize strong ... -
A Two-Point Boundary Value Problem for a Second Order Differential Equation with Parameter
( Qatar University , 1982 , Article) -
Ultrastructural localization of acid and alkaline Phosphatases, glucose-6-phosphatase and odium-potassium Atpase enzymes in the neurosecretory and oesophageal Cells of earthworm
( Qatar University , 1994 , Article)In the present study we have localized acid and alkaline phosphatases, glucose-6-phosphatase and sodium-potassium ATPase (Na-K-ATPase) in ultra-thin sections of cerebral neurosecretory cells and oesophageal cells of the ... -
ultrastructural observations on the effect of the insecticide "aldrin" on some neurosecretory cells of the cerebral ganglion of the earthworm aporrectodea caliginosa
( Qatar University , 1994 , Article)The effect of the insecticide "Aldrin" on the neuroglia and neurosecretory cells of the earthworm Aporrectodea caliginosa was studied. The fine changes on the organdies of certain neurosecretory cells was observed by light ... -
Ultrastructural Study Of Type "B" Neurosecretory Cells In The Earthworm Nervous System
( Qatar University , 1991 , Article)Neurosecretory cell types Bi—B5 are widely distributed throughout the cerebral, subesophageal, nerve cord and peripheral ganglia of the oligochaete Aporrectodea caliginosa, Lumbricus terrestris, Eisenia foetida, Octolasion ... -
The ultrastructure of some stages of haemogregarina Tarentannulari infecting the gecko Tarentola annularis
( Qatar University , 1995 , Article)Certain blood and schizogonic stages of Haemogregarina larentannulari - occuring in the vertebrate host Tarenlola annularis - were studied by electron microscopy. Certain crylhrocytic stages, as well as some schizogonic ... -
Urea Hydrolysis and Urease Activity in Saudi Arabian Soils
( Qatar University , 2000 , Article)Soil samples were collected from eight different localities m Saudi Arabia, and analysed for mechanical properties as well as for urea hydrolysis. The urease enzyme activity of these calcareous soils was also investigated. ... -
Variability Of Wind System And Its Expected Effects On Oil Slick Movement In The Arabian Gulf
( Qatar University , 1992 , Article)The marine data required for the models of the oil spill movement prediction (current and wind data) are discussed. The available water current data in the Arabian Gulf can not be used with confidence because of lack of ... -
Variation Of The Electrical Properties Of Manganese Thin Films With Deposition Conditions
( Qatar University , 1989 , Article)The behaviour of the electrical properties of manganese thin films of different thickness (240 - 1500 A) evaporated under different deposition conditions was studied. The effect of the rate of evaporation (1-7 A/s), the ... -
Vertical Distribution And Inter-Relations Of Oxygen And Nutrients In The Arabian Gulf And The Gulf Of Oman In Summer
( Qatar University , 1990 , Article)The distribution patterns of oxygen and nutrients (phosphate, nitrate, nitrite and ammonia) were studied along the Arabian shelf of the Arabian Gulf and the Gulf of Oman, including the Strait of Hormuz, during September, ... -
Vibrational Analysis Of TaBr5
( Qatar University , 1987 , Article)Vibrational analysis for TaBr5 is achieved on the basis of D3h symmetry and employing GF matrix method. Each vibration is quantitatively assigned according to the calculated values of the potential energy distributions. ... -
Viscous Behavior of Dilute CMC Salt Solution Before and After Photodegradation
( Qatar University , 2006 , Article)Photodegradation curve of carboxymethylcellulose (CMC) in aqueous solution has been reported. Densities and solution viscosities of very dilute CMC salt solution before and after UV-irradiation have been measured. ... -
Vitamin - a and limb regeneration in stages of the egyptian toad, bufo regularis Reuss-histological study
( Qatar University , 1995 , Article)The histogenesis of regenerated limbs, of both control and treated /larvae/ with 30 I.U./ml of retinol palmitate for 3 days, was studied in two larval stages (viz. stages 53 & 54) of the anuran amphibian, Bufo regularis ...