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  • 1
    Digitale Medien
    Digitale Medien
    Effects of herbicide and timing of removal on interference between barley and weeds (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Weed research 28 (1988), S. 0 
    Details
    ISSN: 1365-3180
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Field experiments were done during the rainy season of 1984–85 and 1985–86 at Harma, Qatar. A weed survey of barley fields was conducted with the primary purpose of identifying the weed vegetation present. The effects of time of hand-weeding and of application of the herbicide metoxuron on the yield and yield components of barley were studied. Removing weeds at 15,30,45 and 60 days after sowing gave yields similar to that of the clean-weeded check. Neither a critical period nor a threshold density below which no yield loss occurred were observed. Metoxuron (1,2 and 3 kg ha−1) gave good to excellent broad-leaved and grass-weed control. The use of this herbicide at the rate of 1 kg ha−1 showed considerable promise.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3180.1988.tb00810.x
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  • 2
    Digitale Medien
    Digitale Medien
    A study of assimilation and translocation in Cuscuta hyalina Heyne ex Roth., Orobanche ramosa L. and Striga hermonthica Benth. (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Weed research 16 (1976), S. 0 
    Details
    ISSN: 1365-3180
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Quantitative determinations of chlorophyll showed that Cuscuta hyalina and Striga hermonthica possess chlorophyll. No trace of chlorophyll was found in Orobanche ramosa. Autoradiographic evidence showed that both radiocarbon and radiophosphorous moved from host to parasite in alt three species. Photosynthesis occurs in S. hermonthica when the parasite is isolated from its host. The adventitious roots of S. hermonthica and O. ramosa appear to be functional in absorbing a proportion of the required inorganic substances and water. S. hermonthica is a hemiparasite, O. ramosa is a holoparasite but C. hyalina is best described as a partial parasite.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-3180.1976.tb00385.x
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  • 3
    Digitale Medien
    Digitale Medien
    Purification of α-amylase from Bacillus lentus cultures (1992)
    Springer
    Applied microbiology and biotechnology 38 (1992), S. 312-314 
    Details
    ISSN: 1432-0614
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Acetone fractionation of Bacillus lentus culture filtrate yielded the highest α-amylase activity and the 66.6% fraction reached 13-fold that of the crude enzyme preparation. Gel filtration and ion exchange chromatography afforded a pure α-amylase (relative molecular mass, 42 000). The pure enzyme was highly active on starch and dextrin. It produced a mixture of oligosaccharides as major products of starch hydrolysis. Maximal activity was reached at 70° C and pH 6.1. Ca2+, Na+, K+ and Sr2+ ions stabilized or slightly stimulated the enzyme whereas Ag+, Co2+, Hg2+, Zn2+, Cd2+ and Fe3+ ions strongly inhibited the activity. The enzyme contained 16 amino acids, of which aspartic and glutamic acids were present in the highest proportions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00170078
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  • 4
    Digitale Medien
    Digitale Medien
    Pattern in the distribution of Acacia tortilis (Forsk.) Hayne (1986)
    Springer
    GeoJournal 12 (1986), S. 403-407 
    Details
    ISSN: 1572-9893
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract The distribution pattern of the Acacia tortilis in several sites in Qatar was investigated using the Greig-Smith-Kershaw method of pattern analysis. Neither random nor regular dispersion were detected and the distribution of the species was of the contagious type in almost every site. Pattern analyses showed two consistent scales: a smaller scale pattern attributed to an intrinsic factor of restricted dispersal of seeds and a larger scale pattern related to past and present biotic interference.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00262363
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  • 5
    Digitale Medien
    Digitale Medien
    Soil properties and moisture characteristics and their relationship with crop mid-day stress in the Sudan Gezira (1991)
    Springer
    GeoJournal 23 (1991), S. 233-237 
    Details
    ISSN: 1572-9893
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geographie
    Notizen: Abstract This study is mainly about the relationship of the moisture holding and release capacity of soils with their texture, particularly the clay fraction. Soil samples collected from various sites in the Sudan Gezira were analysed for physical and chemical properties and moisture characteristics. Generally the soils were clayey except the recent alluvium which was loamy. The pH was alkaline and the electric conductivity 〈 1.0 dS m−1. The studied soils were calcareous and very poor in organic matter, their intermediate to high water holding capacity being due mainly to the presence of large quantities of clay. Matric potentials of −0.4 to −1.5 MPa reduced soil moisture for all types of soils but the effects were not necessarily quantitatively equal. Permanent wilting point — moisture content at − 1.5 MPa — varied widely (10.5 – 22.0%) amongst the different soils and this was mainly attributed to texture and mineralogy of the soil clays. Bulk density decreased with increase in clay content. Calcium carbonate content was found to have no apparent relationship with the moisture content of these soils. The amount of silt fraction seems to have an overriding effect on the relationship between soil moisture availability in the recent alluvium soil and its subsequent release to growing plants. The results are discussed in relation to the phenomenon of mid-day stress observed in all grown crops of the Sudan Gezira.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00204840
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  • 6
    Digitale Medien
    Digitale Medien
    Production and properties of fibrinolytic enzyme fromStreptomyces sp. NRC 411 (1992)
    Springer
    World journal of microbiology and biotechnology 8 (1992), S. 267-269 
    Details
    ISSN: 1573-0972
    Schlagwort(e): Enzyme ; fibrinolysis ; Streptomyces
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract Of 16Streptomyces spp. investigated for the production of extracellular fibrinolytic enzyme, one species was chosen as the most promising producer. Using shaken cultures grown for 7 days, optimal conditions for enzyme production were pH 6.0, 5% (w/v) starch as carbon source, (NH4)2SO4 and soybean flour as nitrogen sources and KH2PO4 at 1.2 g/l. Maximal activity of the crude enzyme was at pH 6.0 and 45°C. Holding the enzyme at 37°C for 2 h decreased the activity by only 10%.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01201876
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  • 7
    Digitale Medien
    Digitale Medien
    Least-squares optimum-order regional geothermal gradient determination from deep borehole temperature data with application to the Western Desert of Egypt (1993)
    Springer
    Studia geophysica et geodaetica 37 (1993), S. 302-314 
    Details
    ISSN: 1573-1626
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Architektur, Bauingenieurwesen, Vermessung , Geologie und Paläontologie , Physik
    Notizen: Summary This paper discusses an approach to determining the least-squares optimum order of a polynomial fit to temperature-gradient data. The optimum is reached when two successive least-squares regional maps are sufficiently similar. This similarity is measured by the correlation factor between the polynomials. The approach was applied to the available deep bore-hole temperature data in the central part of the Northern Western Desert of Egypt. The fitting polynomial was found to be of the second degree. Assuming the thermal conductivity to be uniformly 2·2 Wm−1K−1 for the stratigraphic section in the Western Desert, the heat-flow density ranges between 35 and 70 mW/m2.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01624603
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  • 8
    Digitale Medien
    Digitale Medien
    Alkalien (1938)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 113 (1938), S. 285-288 
    Details
    ISSN: 1618-2650
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01358330
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  • 9
    Digitale Medien
    Digitale Medien
    Zirkonium, Hafnium, Thorium, Germanium (1938)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 113 (1938), S. 213-221 
    Details
    ISSN: 1618-2650
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01604244
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  • 10
    Digitale Medien
    Digitale Medien
    Kinetics and mechanism of isatin ring opening in aqueous binary mixtures of methanol and acetonitrile cosolvents (1998)
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 30 (1998), S. 463-469 
    Details
    ISSN: 0538-8066
    Schlagwort(e): Chemistry ; Physical Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Solvent effects on the kinetics of hydrolysis of isatin by sodium hydroxide have been investigated within the temperature range (30-55°C) in methanol-water and acetonitrile-water media of varying solvent compositions up to 70% (v/v) of the organic solvent component. The thermodynamic activation parameters were calculated and discussed in terms of solvation effects. The determined isokinetic temperatures, in both systems, revealed the existence of compensation effect arising from strong solute-solvent interactions; log k was correlated with both log [H2O] and the reciprocal of the dielectric constant. The first correlation was observed to be linear while the second was nonlinear. Finally a mechanism for the isatin ring opening was proposed, which accounts for the role and the effect of the solvent on the reaction rate. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 463-469, 1998
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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