Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 369-388 of 770
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Late Maastrichtian And Paleocene Calcareous Nannofossils From Ain Dabadib Section, Nw Kharga Oasis, Egypt
( Qatar University , 1991 , Article)On terms of calcareous nannofossils, the late Maastrichtian and Paleocene sediments were subdivided into several biozones. The Cretaceous-Tertiary boundary is marked by a hiatus concerning the latest Maastrichtian and the ... -
Lead-Induced Malformations and Kidney Destruction of Developing Chick Embryos
( Qatar University , 1993 , Article)Two doses of lead nitrate, 0.5 and 0.1 mg/egg, were injected into the eggs after 3 days of indubation. Lead nitrate increased mortality rate and decreased the body weight of developing embryos. The lead nitrate also decreased ... -
Light Microscopic Study On Schistosoma Mansoni Induced Hepatic And Splenic Lesions Following Praziquantel Treatment
( Qatar University , 1989 , Article)Hepatic and splenic lesions were developed in mice of both sexes following their exposure to cercariae of Schistosoma mansoni (70 cercariae / animal). After 12 weeks of infection, the liver showed the formation of typical ... -
The Likelihood Function For A Progressive Disease Model With A Bivariate Survival Function
( Qatar University , 1995 , Article)A model for the natural history of a progressive disease is developed. The model has three disease states and can be expressed as the joint distribution of two survival random variables. Covariate information is incorporated ... -
Lineament Analysis Of Qatar Peninsula Based On Landsat Imagery
( Qatar University , 1990 , Article)Photo-interpretation of Landsat MSS images of Qatar Peninsula reveals several surface lineaments of different types, extentions and trends. Some of these photo-lineaments are of structural nature while others represent ... -
Liquid chromatographic separation of the enantiomers of racemic A aminophosphonates as their n-3, 5-dinitrobenzoyl derivatives On chiral fluorocarbinol stationary phases
( Qatar University , 1994 , Article)The enantiomers of a wide variety of a-aminoaryl (or alkyl) phosphonate esters are separated by liquid chromatography as their N-3,5-dinitrobenzoyl derivatives on three chiral fluorocarbinol stationary phases. In addition ... -
A List of Marine Algae from Seashores of Iran (Hormozgan Province)
( Qatar University , 1999 , Article)Seashores of Hromzgan province in south of Iran were studied for collection and recogna-tion of algal flora (1991-1996). 150 species of marine algae were recognized, including 36 Chlorophyta (16 new). 33 Phaeophyta (15 ... -
Lithofacies and depositional environments Of the lower jurassic sediments In central Saudi Arabia
( Qatar University , 1999 , Article)The lithofacies, microfacies and sedimentary environments of the surface Lower. Jurassic sediments in central Saudi Arabia are studied. The Lower Jurassic is represented by the marine clastic Marrat Frormation which is ... -
Lower Eocene Black Shale Beds Of Rus Formation In North Of Oman-Possible Oil Shales
( Qatar University , 1994 , Article)A suite of samples from some black shale beds of lower Eocene Rus Formation from north of Oman have been investigated through detailed geochemical analyses. The obtained results indicate that these shale beds contain a ... -
Lumping Processes of Periodic ARMA Processes
( Qatar University , 2004 , Article)In this article various lumping processes are defined for periodic ARMA (PARMA) processes, namely, the forward, the backward and the cyclic lumping processes. The inter-relations between the parameters of these lumping ... -
Magnetic Studies on High - Tc Bi - Pb- Sr - Ca - Cu - O Ceramics
( Qatar University , 1997 , Article)The superconducting material with a nominal composition BiI 6 Pb0 4 Sr2 Ca2 Cu3 Ox has been recently synthesized and characterized by the authors using the Q- factor method. The Q-factor data reported in this work shows ... -
Mangrove As A Bioindicator For Environmental Pollution In The Coastal Marine Environments-Review
( Qatar University , 1999 , Article)Mangrove stand components have been used widely as bioindicators for different types of environmental pollution including heavy metals, organic pollutants and hydrocarbons as as well as in the detection of ozone depletion ... -
Marine Algae As Bioindicators Of Pollution Levels In The Arabian Gulf
( Qatar University , 1995 , Article)The extensive distribution of several marine macroalgal species makes them a potential bioindicator tool for monitoring existing levels of different types of marine pollutants in the region. The present work illustrates ... -
The marine Mollusca of the Qatari waters, Arabian Gulf
( Qatar University , 1997 , Article)The species composition of the mollusca community in the Qatari waters of the Arabian Gulf, is reported. Data were obtained from analysis of samples collected during 1996 - 1997. A total of 246 species were recorded, ... -
A Markov Chain Model For River Flow
( Qatar University , 1996 , Article)This paper is concerned with a trinary transformation of river flow. The transformed flow is modeled as a three-states Markov chain and both upcrossing and downcrossing problems are studied simultaneously. The stationary ... -
A Mathematical Model Of The Dynamics Of Schistosomiasis
( Qatar University , 1996 , Article)In this work the authors develop a mathematical model for the dynamics of a major helminth parasite of man, schistosomiasis. The model is a system of coupled non-linear equations. Numerical experimentations with the model ... -
Measurements Of Radon Permeability Through Some Membranes
( Qatar University , 1994 , Article)The diffusion of 222Rn through different types of membranes has been studied by an equilibrium method using a Si surface barrier a-detector with a resolution of 14 keV FWHM for ^'Am. The permeability constant for Aluminized ... -
Mechanism of Dehydration of Ethanol over Alumina
( Qatar University , 1981 , Article)The dehydration reaction of ethanol to ether and ethylene was kinetically investigated in a flow system using •y-alumina. Pyridine was found to inhibit the formation of ethylene and ether. The rate of ethylene formation ... -
Mechanism Of The Inhibition Afforded By Some Hydrazone Oxime Derivatives Towards Aluminium In 2m Naoh Solution
( Qatar University , 1991 , Article)The effect of some hydrazone oxime derivatives on the corrosion of aluminium in 2M NaOH solution was studied by polarization and weight-loss techniques. Polarization data indicated that all inhibitors tested were of a mixed ... -
Meiofaunal Life of Man-Made Wastewater Ponds in Qatar
( Qatar University , 2002 , Article)The meiofaunal life of two wastewater ponds around Doha City was studied for the period October 2000-October 2001. The substrate nature of the two ponds was found to be similar in mean particle sizes but the densities of ...
