Qatar University Science Journal - [From 1981 TO 2007]: المرسلات الحديثة
السجلات المعروضة 61 -- 80 من 770
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Ferricretes of the Early Tertiary Dammam Formation in the Dukhan Area, Western Qatar: mineralogy, geochemistry, and environment of deposition
( Qatar University , 2003 , Article)Ferricretes of the Middle Eocene Dammam Formation, Western Qatar, were investigated using petrographic and ore microscopy, IR TGA, XRD, and geochemical analyses. The ferricretes mainly consist of goethite, which is very ... -
Mycoflora And Natural Occurrence Of Mycotoxins Of Chicken Stock
( Qatar University , 1993 , Article)Twenty four species and one species variety (belonging to 11 genera) and 20 species with the addition of two species varieties (belonging to 7 genera) were isolated on glucose-Czapek's agar and glucose-Czapek's agar medium ... -
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 ... -
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 ... -
Record of a fruiticose lichen, Ramalina farinacea (L.) Ach. for Qatar
( Qatar University , 1997 , Article)Lichens are thallophytic lower plants. Ramalina farinacea (L.) Ach., family Ramalinaceae, is the only fruticose lichen recorded in Qatar. It occurs on stony terrain bordering the coastline in association with other more ... -
Nannobiostrat1graphy Of The Late Cretaceous Paleocene Succession In Esh El-Mallaha Range, Eastern Desert, Egypt
( Qatar University , 1990 , Article)This paper emphasis the biostratigraphic significance of thirty nannofossil species recorded from the Maestrichtian - Paleocene succession in Esh El-Mellaha Range, Eastern Desert, Egypt. These species participated in making ... -
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 ... -
Charge transfer complex formation constants of edta with methylviologen And its zwitterionic derivatives
( Qatar University , 1994 , Article)In the photochemical cycle of the labelled, tris (2,2'bipyridine) ruthenium(II), Ru(bpy)32+, the photo excited label is oxidized through electron transfer quenching by methylviologen (l,l'-dimethyl-4,4'-bipyridinium dication, ... -
A study of contamination of the northern Jordan valley agricultural fields by various metal ions using regression analysis.
( Qatar University , 2000 , Article)Geochemical analysis were performed in lower subsurface soil samples of 10,20,30 and 40cm depth, collected from seven regions in the northern Jordan valley. Eighteen descriptors (variables) for each sample were used. Among ... -
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 ... -
Geology, Petrography, Geochemistry And Petrogenesis Of The Egyptian Younger Granites
( Qatar University , 1990 , Article)One hundred and thirty nine new chemical analyses of major and trace elements for 26 plutons and masses pertaining to the Egyptian Younger Granites are presented together with the chemical analyses of 13 biotites, 32 ... -
Diagenesis of the middle eocene "nummulite bank" of The giza pyramids plateau, Egypt: petrologic and 18o/16o evidence
( Qatar University , 1994 , Article)The Middle Eocene "nummulite bank" of the Giza Pyramids Plateau has been extensively altered diagenetically. The result of a study involving petrography, cathodoluminescence, and 18O/160 and 13C/12C data, provide information ... -
Tectonic Setting and Petrogenetic Evolution of Wadi Erier Rocks, South Eastern Desert, Egypt
( Qatar University , 2003 , Article)A combination of geologic, petrographic and chemical criteria is used to classify the Erier basement rocks into three suites namely, the metagabbro-diorite (MGD) suite, the tonalite-granodiorite (TG) suite and the ... -
Gravitohydrodynamic Instability Of A Streaming Fluid Cylinder
( Qatar University , 1996 , Article)The capillary-gravitodynamic instability of a self-gravitating fluid cylinder (radius R«) dispersed in a self-gravitating medium of negligible motion has been developed. General stability criteria are derived, upon utilizing ... -
Preliminary Assessment of the Effect of Saline Water Used in Irrigation on the Growth of the Local Barley Cultivar (Harma)
( Qatar University , 2001 , Article)ABSTRACT The effect of gradual increase m soil salinity, using diluted solutions ofseawater, on growth and yield of the local barley cul-tivar (Harma) was examined. Harma barley did not withstand osmotic shock higher than ... -
A 6th-order local approximation by a cubic curve
( Qatar University , 1997 , Article)We derive and present a MAPLE program for the construction of a parametric cubic polynomial curve which has sixth-order contract with a given smooth curve at a given point, thus providing a local sixth-order approximation ... -
Palaeozoogeography of Shallow Marine Ostracoda from Holocene Sediments-Southern Iraq
( Qatar University , 1999 , Article)The Holocene palaeozoogeography of southern Iraq (Southern Mesopotamian Basin) have been studied according to the distribution of thirteen species of shallow marine ostracoda belonging to twelve genera. Their distributary ... -
Nitrogen Transformations As Affected By Some Factors at Cultivated Soils In Saudi Arabia
( Qatar University , 2000 , Article)The influence of serial concentration of salts (0.5, 1.0 and 1.5%), application of organic matter (0.5, 1.0 and 1.5% of wheat straw) and varying soil moisture content (50, 70 and 90%) on nitrification in sandy loam soil ... -
Sulphur Oxidation In Saudi Arabian Agricultural Soils
( Qatar University , 1996 , Article)Laboratory studies were conducted to determine the oxidation of elemental sulphur in eight localities of Saudi Arabian soils. The effect of sulphur application on related properties of calcareous soils in Saudi Arabia was ... -
The Effect of Cutting Height on Forage Yield and Performance of Alfalfa Cultivars
( Qatar University , 1999 , Article)Six exotic alfalfa (Medicago sativa L.) cultivars were evaluated for their forage yield performance and persistency under different cuttings heights during 1991/1992 in UAE. Cultivars revealed a highly significant difference ...
