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Now showing items 121-130 of 451
Pyrrolizidine alkaloids from alkanna orientalis (L.) Boiss
(
Qatar University
, 1992 , Article)
Three pyrrolizidine alkaloids; 7-angelyl retronecine (I), 9-angelyl retronescine (II), and dihydroxytriangularine (III) were isolated by DCCC and VLC from Alkanna orientalis growing in Egypt. Their structures were elucidated ...
Homomorphisms And Subalgebras Of Ms-Algebras
(
Qatar University
, 1995 , Article)
According to the characterization of MS-algcbras from the subvaricty Kj by mean of the triple construction, we characterize the homomorphisms and the subalgebras of the MS-algcbras. Also, we solve the "Fill-in" problem for ...
A critical analysis of "harvest index"
(
Qatar University
, 1993 , Article)
The many ways in which harvest index ratio (HI) can be used are discussed. A selection of published values for HI are given. Attention is drawn to the confusion in calculating the HI such that some present methods of ...
Histology And Development Of Argas (Argas) Hermanni (Ixodoidea: Argasidae) Salivary Glands
(
Qatar University
, 1993 , Article)
The anatomy and histology of Argas (Argas) hermanni salivary glands were studied during nymphal and adult development. The paired salivary glands consist of 2 alveolar types. Type I alveoli consist of several cells forming ...
Incidence and characterization of bacillus cereus isolated From egyptian foods.
(
Qatar University
, 1993 , Article)
In this study, 178 strains of Bacillus cereus were isolated from different Egyptian foods. Isolation was performed, using MYP and PEMBA media and confirmed by staining and biochemical tests. B. cereus occurred in 98% of ...
Effects of electric and magnetic fields on the energy levels of a hydrogenic impurity in GaAs/Gal-xAl x As heterjunction
(
Qatar University
, 1997 , Article)
Variational method within the effective — mass approximation is used to calculate the shallow impurities states in GaAs / Gai_xAl^As heteroj unctions. Modified Fang-Howard wavefunction is used as the trial wavefunction. ...
Functional adaptations of fig trees (ficus carica, l.) In agroecosystems of the western mediterranean desert of Egypt.
(
Qatar University
, 1991 , Article)
The ecophysiological characteristics of fig (Fi'cus carica, L.) trees, growing with maximum activity during the hot and dry summer, were studied in relation to growth, carbon partitioning, nutrient balance and water use. ...
Constituents of plants growing in qatar xxv flavonoids of Picris Radicata (forssk.) Less.
(
Qatar University
, 1994 , Article)
Four flavonoids were isolated from the plant and were identified as apigenin, chrysin 7-glucoside, leuteoline and luteolin 7-glucoside.
Balanced Cross-Section Across The Southern Utah Overthrust Belt (Otb)
(
Qatar University
, 1995 , Article)
Balanced cross-sections are offering the chance of better understanding of areas of complex geological structures that are insufficiently understood.
Detailed field study and structural analysis by employing geometric ...
Effects Of Chemical Pesticides On The Gravid Females And Stadia Of The Woodlouse, Porcellio Scaber (Latreille) (Isopoda, Oniscidea)
(
Qatar University
, 1991 , Article)
Studies were made on the mortality rates of the gravid females, and on the survival and growth rates of the stadia of the woodlouse Porcellio scaber (Latreille) exposed for a period of 21 days to sub-lethal concentrations ...