Qatar University Science Journal - [From 1981 TO 2007]: Recent submissions
Now showing items 621-640 of 770
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Studies on growth and chemical composition of tobacco varieties. IV - comparative effects of various combinations of fertilizers on economic potentialities of tobacco plants
( Qatar University , 1987 , Article)In two experiments, tobacco plants were treated with various combinations of ammonium nitrate (23% N) and compound C (3.5% N, 23% P and 16% K). At all levels used in experiment I, stem length and number of leaves were ... -
Distribution And Mineralogy Of The Clay Deposits In Saudi Arabia
( Qatar University , 1993 , Article)The main goal of this paper is to characterize the mineral clay deposits in Saudi Arabia; especially their mineral composition, deposit size, geological setting and possible uses. Different published reports and papers on ... -
A convenient synthesis of Carbocyclic fused Thieno [2,3-b] Pyridines and Carbocyclic fused IH-Pyrazolo [3,4-b] Pyridines
( Qatar University , 2001 , Article)A synthesis of Carbocyclic fused thieno [2,3-b] pyridines and carbocyclic fused 1H- pyrazolo [3,4-b] pyridines utilizing car-bocyclic fused 2(lh)-pyridinethiones as starting components is described. The structures of the ... -
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 ... -
Geochemistry of the st. Catherine basement rocks, Sinai, Egypt
( Qatar University , 1994 , Article)St. Catherine area, dominated by basement rocks encompass old continental gneisses, metasediments, greenstone belt, calc-alkaline granites (G-II-granites), rift-related volcanies (RV), and anorogenic within plate granites ... -
Factors Governing Mosquito Susceptibility To Bacillus Sphaericus Strains
( Qatar University , 1992 , Article)Three lyophilized strains of Bacillus sphaericus (1593-4, 2297 and SSII) were tested against four different mosquito species. Culex pipiens larvae demonstrated the highest level of susceptibility towards the 3 B. sphaericus ... -
Monovalent Anion Interaction on the Electron Flow of Photosystem II in Soyabean Cells
( Qatar University , 1994 , Article)Steady state of electron transport measurements from water to DMQ (2, 5 - dimethyl - P- benzoquinone) show a maximum bicarbonate effect (about four fold stimulation) following the addition of 5 mM HCO"3 to the previously ... -
Pollen Morphology of some Cultivated Varieties of Strawberry
( Qatar University , 1999 , Article)Pollen grains of twelve cultivated varieties of strawberries grown in Egypt were morphologically studied using both light microscopy and SEM observations. These varieties include eleven cultivars of Fragaria x ananassa ... -
Bayes Estimation of the Parameter of Burr Type II Distribution in Case of Type II Censoring
( Qatar University , 1997 , Article)Suppose that Xj, X2, ..., Xn is a random sample of failure times from a Burr type II (B2) distribution with parameter 9. Let x = (xj, x2, , xr) with xj < x2 S x3 < < xr be the observed failure censored sample of the first ... -
Assessment of heavy metal accumulation and performance Of some physiological parameters in zea mays l. And Vic1a faba l. Grown on soil amended by sewage Sludge resulting from sewage water Treatment in the state of qatar
( Qatar University , 1995 , Article)Pot experiment was conducted to explore extent of concerns regarding agricultural use of sewage sludge for crop production in the state of Qatar. Extent of heavy metal accumulation and its subsequent impact on physiological ... -
The electrical and optical properties of poly (4-ethylidene-l, 3-cyclopentylene vinylene)
( Qatar University , 1989 , Article)The intrinsic viscosity, electrical conductivity and IR absorbance were measured for the sample of poly (4—ethylidene—1, 3—cyclopentylene vinylene). The sample is strongly oxidized in air. Under vacuum the activation energy ... -
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, ... -
A Mixed Markovian Time Series Model
( Qatar University , 1997 , Article)We study a simple time series model the noise properties of the proposed model are derived. An algorithm based on the conditional mean and the conditional variance, for estimating the parameters of the proposed model is ... -
Stability of Logistic Autoregressive Model
( Qatar University , 2007 , Article)In this paper we propose a Logistic Autoregressive Model, which is a special case of polynomial Autoregressive Model. The aim of this paper is to study and find the stability conditions of the above model by using a dynamical ... -
Phospholipid Fatty Acids Compositions of Sponges from Qatar I- Haplosclerida
( Qatar University , 2006 , Article)The phospholipid fatty acid contents of six Haplosclerida sponges collected along Qatari ;ts, Arabian Gulf, were identified by coupling GC-MS experiments. More than hundred of rated and unsaturated fatty acids have been ... -
Bio Accumulation Of Chromium, Nickel, Lead And Vanadium In Some Commercial Fish And Prawn From Qatari Waters
( Qatar University , 1997 , Article)A total of 150 fish and prawn samples representing the most economically important species were collected during 1995-96 by experimental fishing in three locations covering the coastal waters of Qatar. Fish and prawn flesh ... -
The Reproducing Capacity of Gamma Irradiated Adults of Trogoderma Versicolor (Creutz)
( Qatar University , 1993 , Article)Male and female, Trogoderma versicolor (Creutz.) were irradiated by gamma radiation as newly emerged adults (12-24 hrs. after emergence). Males required higher doses than females to be sterilized and the reproductive ... -
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, ... -
Effects of the expected sea level rise on avicennia marina L: a case study in Qatar
( Qatar University , 1995 , Article)A simulation of the expected sea levels rise was carried out by imposing a state of protracted flooding on seedlings of the mangrove species Avicennia marina L. under natural conditions. The imposed flooding resulted in ... -
Biochemical studies on the blood and tissue components of the common Egyptian toad bufo regularis
( Qatar University , 1995 , Article)The effect of insulin and/or cortisone on the blood, serum and tissue levels of glucose, glycogen, pyruvic acid, lactic acid cholinesterase, alkaline phosphatase, aspartate amino transferase (AST), alanine amino-transferase ...
