Browsing Qatar University Science Journal - [From 1981 TO 2007] by Title
Now showing items 359-378 of 770
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Investigations on the growth abnormalities of medicago sativa l. Under field conditions
( Qatar University , 1996 , Article)Morphological growth abnormalities were pursued and studied in field-grown alfalfa (Medicago sativa L.) in Al-Kharj agricultural area, south east of Riyadh. Significant differences between normal and abnormal plants were ... -
Iodometric microdetermination of phosphorus in organic compounds by use of An amplification reaction
( Qatar University , 1994 , Article)A high chemical amplification method is described for the iodometric microdetermination of phosphorus in organic compounds. This method depends on combustion by the oxygen flask, absorption of the combustion products in ... -
Ionic Conductivity and Ionic Jump Distance of Nuclear Detectors Group CR-39 and BM-355
( Qatar University , 2000 , Article)Electric properties of two nuclear detectors (CR-39 and BM-355) have been investigated as a function of temperature differences. The conductivity appears to be ionic and it was increased with the temperature increase for ... -
Irrigation, Planting Date And Intra-Row Spacing Effects On Soybean Grown Under Dry Farming Systems
( Qatar University , 1987 , Article)Two soybean cultivars (Glycine maxima (L) Merr.) differing in maturity period, leaf size and stem height were sown five times at fortnight intervals during the rainy season at four intra—row spacings under supplementary ... -
Isolation and Characterization of Pollulan Produced by a Local Isolate of Aureobasidium Pullulans
( Qatar University , 2000 , Article)A local isolate of Aureobasidium pullulans was obtained from fig leaves surface. The isolate was identified as A. pullulans on the basis of appearance of polymorphism in the colonies, melanin pigment and pullulan production ... -
Karyotype, Meiosis And Sperm Formation In The Land Snail Macrochlamys Indica
( Qatar University , 1994 , Article)Karyotype analysis, meiosis and sperm formation of the land snail Macrochlamys indica collected from different farms of ornamental plants in Doha city of the State of Qatar were investigated. The chromosome number is n=24 ... -
Khashm Formation, A New Lithostratigraphic Unit Within The Cretaceous Wasia Group Of Arabia
( Qatar University , 1988 , Article)The Khashm Formation is introduced as a new lithostratigraphic unit to include the sandstones and shale interbeds which constitute the upper part of the Cretaceous Wasia Group (s. /.) outcropping in central Arabia. It ... -
Kinetics and Mechanistic Studies of the Bromination of Some Substituted Tetralones, Part 1
( Qatar University , 2000 , Article)The rate of bromination of 2-benzal-l-tetralone (II) and its derivatives p-methyl (12), 77-chloro (13), ffi-chloro (14), and p-nitro (15) have been studied in chloroform. The study indicated first order dependence on each ... -
Krein's Method For Singular Mixed Problems
( Qatar University , 1993 , Article)In this paper, the spectral relations of the Fredholm integral equation of the first kind for the mixed problems with singular kernel are obtained. -
Krein's method for solving the integral equation of the first kind With logarithmic kernel
( Qatar University , 1993 , Article)Consider the Fredholm's integral equation of the first kind with logarithmic kernel K(IXI) = (- In Ixl. The aim of this paper is to establish the equivalence of Krein's method of solving the equation with the following ... -
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 ...