Qatar University Science Journal - [From 1981 TO 2007]: Recent submissions
Now showing items 361-380 of 770
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Subsurface geothermal investigation in the nile delta, egypt.
( Qatar University , 1983 , Article)The Nile Delta area is geothermally studied to define the behaviour of geothermal gradient in different wells and to determine the distribution of heat in some interesting rock formations. The geothermal investigation of ... -
Total Mercury Levels In The Coastal Environment Of Qatar (Arabian Gulf)
( Qatar University , 1999 , Article)The levels of total Mercury (t-Hg) were determined in various segments of the marine environment of Qatar. Several coastal stations, both on the East as well as the West coast of Qatar were worked for t-Hg in seawater, ... -
Cellulose - Decomposing Fungi From Saudi Arabian Soils
( Qatar University , 1996 , Article)Thirty fungal species belonging to fifteen genera were collected from 30 soil samples on cellulose Czapek agar. The highest number of fungal species was isolated from Dammam (20 species) followed by Niomas (18 species), ... -
Effects Of Gamma Radiation On The Sexual Attraction Of The Mediterranean Fruit Fly. Ceratitis Capitata Wied
( Qatar University , 1987 , Article)The Mediterranean fruit (ly, Ceratitis capitata Weid, was gamma irradiated as full grown pupae with 50, 70 and 90 gray. The produced adults were examined for their attractiveness to the non irradiated (normal) other sex. ... -
Constituents Of Centaurea Species
( Qatar University , 1992 , Article)A comprehensive review of Centaurea species including all the isolated consituents is given. The biological activities of the studied species are also reported. -
Regional catecholamine concentrations in brain and spinal cord of male albino rats treated with the synthetic pyrethroid cyfluthrine
( Qatar University , 1997 , Article)The principal objective of this study was to determine the modifications induced by the synthetic pyrethroid insecticide cyfluthrin in the concentrations of dopamine (DA), norepinephrine (NE) and epinephrine(E) in selected ... -
New Contributions To The Geology, Geochemistry And Tectonic Setting Of The Aswan Granites, Southern Egypt
( Qatar University , 1990 , Article)The Aswan granitic rocks occupy a region in southern Egypt between the stable Archaean craton of the south Western Desert and the less stable Pan-African belt of the south Eastern Desert. They include light-grey medium ... -
Constituents of catha edulis (alkaloids, triterpenoids and related substances and saponins)
( Qatar University , 1989 , Article)The study of the alkaloids of khat samples from Egypt and Yemen revealed qualitative and quantitative differences. Cathine and the dimer of cathinone occured in both samples, while norephedine was detected only in Yemen ... -
A Rational Exponential Model for Unconstrained Non-Linear Optimization
( Qatar University , 2002 , Article)In this Paper, a new algorithm based on the non-quadratic model is suggested for solving unconstrained optimization problems which modifies the classical conjugate gradiant methods. This technique has the same properties ... -
Ecology and biodiversity profile of the Genus Streptomyces in the soil of the State of Qatar
( Qatar University , 2007 , Article)Ecology and biodiversity profile of Streptomyces in the soil of Qatar have been studied in 123 soil samples from different sites distributed all over the country. Moisture contents of soils samples ranged between 0.2-8.8% ... -
An Approximation Leading To The Binomial Distribution In The Stochastic Treatment Of A Reversible Chemical Reaction
( Qatar University , 1992 , Article)The exact equilibrium distribution of the number of molecules of C in the reversible chemical reaction A+B ^=S: C is shown to converge to the binomial distribution when N is finite, M—»!K, K—>0 in such a way that KM is ... -
On an inverse scattering problem with a discontinuous coefficient On the whole line
( Qatar University , 1994 , Article)This paper is devoted to study the inverse scattering problem of a generalized Sturm-Liouville equation on the whole line.The solutions of the considered problem and their asymptotic behaviour are presented.The expansion ... -
The Adjoint Problem Of A Modified Sturm-Liouville Boundary Value Problem
( Qatar University , 1993 , Article)The authors give the solutions of the eigenvalue equation that is associated with a modified Stum-Liouille problem. The discrete specturm and hence the resolvent will be obtained by means of different types of solutions ... -
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 ... -
The relationship between heavy metal concentration and soil mycoflora in the Gizan region, Saudi Arabia
( Qatar University , 1997 , Article)Soil samples were collected from different places from the Gizan region, Saudi Arabia, and analyzed mechanically and chemically for mineral content. The soils were highly alkaline and sandy in texture in all cases. The ... -
Modelling Of The Basement Surface Of Siwa-Qattara Depression Area, Northern Western Desert Of Egypt
( Qatar University , 1990 , Article)Modelling study of the basement surface of Siwa-Qattara Depression area was done through the calculation of basement depth for 62 selected points using gravity interpretation methods. The constructed basement relief map ... -
Plant Population Density Effects On Yield Of Sorghum Grown In A Dry-Land Farming System
( Qatar University , 1996 , Article)Plant population studies in arid regions are very sparse and not well documented. A prerequisite in growing a successful sorghum (Sorghum bicolor [L.] Moench) crop is to obtain an adequate plant population. The response ... -
Constituents of plants growing in qatar xxiii. Flavonoids of francoeuria crispa
( Qatar University , 1993 , Article)Investigation of the flavonoid constituents of Francoeuria crispa, resulted in the isolation and identification of four flavonoids: quercetin, qucrcetin-3-O-gIucoside, quercetin-7-0-glucoside and quercetin-3-methyl ether. -
Sequence Of Ossification In The Skeleton Of Growing Lizard Chalcides Ocellatus Forscal (Scincidae, Reptilia)
( Qatar University , 1988 , Article)The distribution of cartilaginous and ossification rudiments were described in the live-bearing lizards, Chalcides ocellatus, at birth, one-month-old, and 12-month-old. The skeletal elements investigated are: neurocranium, ... -
Ecological Notes On The Floristic Composition And Endemic Species Of Saint Catherine Mountains, South Sinai, Egypt
( Qatar University , 1995 , Article)The present study is aimed at (1) giving complete list of all plant speciec growing in Saint Catherine mountains, (2) studying the relationship between species number and the amount of precipitation at the time of study ...
