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  • Author or Editor: A. Mohamed x
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Abstract  

Multielemental instrumental neutron activation analysis has been utilized for the determination of micro, trace and ultratrace amounts of Al, As, Au, Br, Ca, Cl, Co, Cr, F, Fe, K, La, Lu, Mg, Mn, Na, Sc, V and W in sugar cane refuses of Armant, Kom Ombo, Edfu, Deshna and Naga Hammady Factories. The element concentrations are below the safety baseline levels. Variations of results may be related to different botanic structures, different compositions of sugar cane plants or ecologic changes in soil. The method is accurate and precise. The relative errors are in the range of 0.3–12.3%.

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Abstract  

A systematic study has been carried out on the extraction of SeI4, by various water-immiscible organic solvents. Extraction has been investigated as a function of H2SO4 and Kl concentrations. It has been found that Se(IV) extraction is appreciably increased by addition of iodide ion to sulfuric acid solutions. On the other hand, the presence of water-miscible alcohols and acetone was found to enhance Se(IV) extraction from H2SO4–Kl solutions. In the light of the results, an extraction mechanism is suggested.

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This study was completed to assess the efficacy of certain chemical inducers (potassium dihydrogen phosphate, potassium monohydrogen phosphate, oxalic acid, salicylic acid, sodium salicylate, ferrous sulfate and magnesium sulfate) compare to flusilazole fungicide against Sphaerotheca fuliginea, the causative fungus of powdery mildew of cucumber under greenhouse conditions. The impact of these elicitors on some biochemical and growth characters of cucumber was also examined. The data demonstrated that the flusilazole was the best treatment against powdery mildew followed by salicylic acid, potassium dihydrogen phosphate, magnesium sulfate, ferrous sulfate, oxalic acid and potassium monohydrogen phosphate, respectively. Marked raise in the measured biochemical parameters (chlorophyll content, peroxidase and polyphenoloxidase) of treated cucumber compare to untreated control. Growth and yield characters (plant height, number of fruits/plant and yield/plant) of cucumber were remarkably increased in cucumber treated with examined elicitors compare to untreated control. The examined chemical inducers could be counted as stand by for control powdery mildew of cucumber.

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Field experiments were conducted at the Agricultural College and Research Institute (Killikulam), Tamil Nadu Agricultural University from September 1992 to June 1995 to optimize the herbicide dose and application techniques for cotton-based intercropping systems.283

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Cucumber (Cucumus sativus L. var. Beit alpha) seedlings were grown in two groups on boron-deficient (traces of boron) and boron-sufficient (10.0 µM boron) hydroponic media for 30 days under controlled conditions. At harvest, the concentrations of magnesium (Mg), iron (Fe), manganese (Mn), zinc (Zn) and copper (Cu) were determined in addition to boron (B) in the dry tissues of roots and leaves. The concentration of phenolic compounds in the roots was also determined. Peroxidase (POD) and catalase (CAT) enzyme activity was assayed in the fresh plant material. In addition, changes in the peroxidase and catalase isozyme patterns were also identified. The results showed that the vegetative growth of cucumber plants was negatively affected by boron deficiency. Biomass accumulation decreased by as much as 24.3% in the shoots and 49.1% in the roots. The nutrient concentrations in both the leaves and roots of B-stressed plants were substantially lower. Phenolic compounds were accumulated in significant amounts in the roots of deficient plants. The peroxidase and catalase enzyme activities were significantly increased in the tissues of deficient plants and new isozymes were induced or activated. The irregular biochemical changes occurring in B-deficient plants were explained as a plant physiological response to B-deficient conditions.

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Abstract  

Multielement neutron activation analysis has been applied to the determination of macro, micro and trace amounts of Al, Br, Ca, Cl, Co, Cr, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sc and V in molasses of Kom Ombo, Edfu, Armant, Naga Hammady and Abu Korkass cane sugar factories. The threshold element concentrations are acceptable and below the safety. Differences in element concentrations may be related to different botanic textures and structures, different compositions of sugar cane plants, corrosion of containers or changes in soil as a result of geochemical differentiation. The method is sensitive down to 0.038 ppm of V. The relative errors due to counting statistics are in the range of 0.2–11%.

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Abu-Dabbab area is characterized by high seismicity and complex tectonic setting, for these facts, a local geodetic network consisting of eleven geodetic benchmarks has been established. The crustal deformation data in this area are collected using the GPS techniques. Five campaigns of GPS measurements have been collected, processed and adjusted to get the more accurate positions of the GPS stations. The horizontal velocity vectors, the dilatational, the maximum shear strains and the principal strain rates were estimated. The magnitude of the movements is distributed inhomogeneous over the area and it varies in average between 3 and 6 mm/yr. The results of the deformation analyses indicate a significant contraction and extension across the southern central part of the study area which is characterized by high seismic activity represented by the clustering shape of the microearthquakes that trending NE-SW direction. The north and north-eastern parts are characterized by small strain rates. This study is an attempt to provide valuable information about the present state of the crustal deformation and its relationship to seismic activity and tectonic setting at Abu-Dabbab area.

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Shallow earthquake swarms of focal depths <10 km and magnitude <4 occurred beneath Aswan Lake in 1987 and 1993. The 1987 events are located along the E-W Kalabsha fault and their focal mechanism solution is strike-slip. Events of the 1993 sequence are distributed along a fault segment trending in the N-S direction and show a strike slip fault plane solution, too. Source parameters of 29 earthquakes from these two sequences are determined using a software developed by the Institute of Geophysics, Polish Academy of Science. The seismic moment and corner frequency data indicate weakness of the focal region of these swarms. The weakness may be produced by the presence of a fractured zone. Horizontal movements, which were collected by Kalabsha local geodetic network, are analyzed for epochs 1984-February 1987, February 1987-September 1987 and September 1987-November 1988. The results show different spatial patterns and magnitudes of the horizontal displacement. The large magnitude of the horizontal displacements suggests that the crustal deformation measurements are mixture of seismic and aseismic components. Moreover, correlation between the geodetic data and the stress pattern deduced from seismicity exists.

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