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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 29 (1999), S. 424-429 
    ISSN: 1432-0789
    Schlagwort(e): Key words Azolla species ; Gibberellic acid ; Megasporocarp percentage ; Sporocarp number ; Sporulation frequency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Azolla microphylla strains used in the study sporulate throughout the year while Azolla caroliniana and Azolla pinnata strains show sporulation only during November–March, the favourable period for sporulation. Application of gibberellic acid (GA) at a concentration of 2.5–100.0 μg ml–1 substantially enhanced the sporulation frequency and number of sporocarps (mega plus micro) per plant in Azolla microphylla (two strains) during the unfavourable period (September–October) by 77.3–200.0%. The increase in the number of microsporocarps was more than that of the megasporocarps. The sporulation frequency and number of sporocarps in Azolla pinnata (two strains) and Azolla caroliniana during the favourable season also increased considerably due to GA (2.5–10.0 μg ml–1) application. The optimum GA concentration for the sporulation of the three Azolla species was 2.5 μg ml–1, which was used in the subsequent investigations. Efficacy of GA for enhancing sporulation was tested across 20 Azolla pinnata strains. A significant positive response was observed in all the strains. Of them, 17 strains for the sporulation frequency and 15 strains for the sporocarp number showed a 〉25% increase due to GA treatment. Under field conditions, Azolla microphylla (two strains), Azolla caroliniana and Azolla pinnata exhibited 66.0–88.1% higher sporulation frequency and 42.8–52.6% higher sporocarp number due to GA application. However, the proportion of megasporocarps to total sporocarps did not change.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Biology and fertility of soils 32 (2000), S. 458-462 
    ISSN: 1432-0789
    Schlagwort(e): KeywordsAzolla genotypes ; Megasporocarp percentage ; Phosphorus fertilization ; Sporocarp number ; Sporulation frequency
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Geologie und Paläontologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract  Phosphorus application decreased the sporulation frequency and number of sporocarps per plant in all the three Azolla species and 21 A. pinnata strains evaluated in this study. The number of megasporocarps tended to be more depressed than the number of microsporocarps. Nevertheless, the sporulation of A. caroliniana was less sensitive to P than that of A. pinnata and A. microphylla. Its sporulation frequency in the mineral medium did not decrease at 2.5 μg P ml–1 and remained unaffected between 5 and 20 μg P ml–1. The sporulation frequency and sporocarp number in this species in the soil culture also were not significantly affected by an increase in the dose of P from 10.7 to 21.4 or 21.4 to 32.1 mg pot–1. Large variations in the degree of inhibition of sporulation due to the application of P (21.4 mg pot–1) also occurred among the A. pinnata strains tested.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 0992-7689
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract An attempt is made to confirm the generation mechanism of plasmaspheric ELF hiss emissions observed aboard GEOS-1 satellite in the equatorial region both at small and large wave normal angles by calculating their magnetic field intensities in terms of incoherent Cerenkov radiation mechanism and cyclotron resonance instability mechanism, using appropriate and suitable plasma parameters. The ELF intensities calculated by Cerenkov radiation mechanism, being 4 to 5 orders of magnitude lower than the observed intensities, rule out the possibility of their generation by this mechanism. On the other hand, the intensities calculated under electron cyclotron resonance instability mechanism are found to be large enough to account for both the observed intensity and propagation losses and hence to confirm that plasmaspheric ELF hiss emissions observed aboard GEOS-1 satellite both at small and large wave normal angles were originally generated in the equatorial region by this mechanism just near the inner edge of the plasmapause. The difference in the observed intensities of two types of the emissions has been attributed to the propagation effect rather than the generation efffect.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Il nuovo cimento della Società Italiana di Fisica 11 (1989), S. 927-932 
    ISSN: 0392-6737
    Schlagwort(e): Fluids, plasmas and electric discharges ; Fermi-Thomas model ; Fusion reactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Summary The screening length of the deuterium ion by surrounding electrons in a palladium metal lattice, as estimated using two approaches—viz. the Thomas-Fermi screening theory and the Debye screening theory for plasmas in metal—is found to be less than the interatomic separation of ordinary hydrogen molecules. This has important implications for the possibility of cold nuclear fusion at room temperature, since slight fluctuations in equilibrium conditions may drive the deuterons to fuse together. The relative magnitudes of screening length for the cold nuclear fusion regime and classical hot nuclear regimes (inertial and magnetic confinement) reveal that in the former a comparatively smaller amount of energy is needed to overcome the repulsive Coulomb barrier between two deuterium ions.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 1660-1665 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Using different optical diagnostic methods, namely interferometric holography and shadowgraphy, and utilizing a piezoelectric transducer for precise velocity determination, the laws of reflection and transmission of laser-driven shock waves through an obstacle in water are studied. Experimental results on the velocity of transmitted and reflected shock waves from different materials are reported.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 59 (1986), S. 281-283 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The eigenvalue problem of whistler propagation in a magnetic trap is analyzed in the slab model. The plasma is comprised of three regions: (I) a≤x〈∞, (II) 0≤x≤a, and (III) −∞〈x≤0. Region II contains a hot-electron component and possesses a smaller magnetic field. The hot electrons have a temperature anisotropy and tend to destabilize the whistler mode. The dip in the magnetic field tends to confine the mode to region II.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 5194-5197 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Shock waves were produced in water by directing unfocused 0.4-J, 20-ns ruby (λ=0.693 μm) or 3-J, 8-ns Nd-glass (λ=1.06 μm) laser light onto the metalized surface of a thin plastic foil. The illuminated areas were 0.35 and 2.3 cm2, respectively, corresponding to laser irradiances of 52.6 and 68.4 MW cm−2. The radial propagation velocity and the profile of the generated waves have been measured via double-exposure interferometric holography and shadowgraphy. Using the obtained values of the shock velocities and the fringe shift in the interferograms, the pressure on the shock wave front, the thickness of the compressed water layer, the laser energy consumed in producing this layer, and the time required for its formation have been calculated.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 21 (1968), S. 0 
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The effects of phosphorus deficiency on carbohydrate fractions of Mentha arvensis L. var. piperascens were studied. Mint plants were grown in sand cultures under full nutrition and phosphorus deficiency conditions. Component organs, viz., leaf, stem and root, were sampled at four different stages of the growth cycle and analysed for various sugar fractions.In leaf and root phosphorus deficiency brought about a definite increase in all sugar fractions whereas in stem a reduction was noticed. The stem appeared to be the principal storage organ throughout the growth. Maximum sugar concentration was recorded at the age of 70 days, which represents the full maturity stage, and coincided with maximum essential oil accumulation.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 24 (1971), S. 0 
    ISSN: 1399-3054
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Biologie
    Notizen: The paper presents effects of phosphorus deficiency and seasonal variations on nitrogen and carbohydrate metabolism of Japanese mint (Mentha arvensis L. var. piperascens, Holmes). Mint plants were grown in sand cultures under full nutrition and under phosphorus deficiency conditions during winter and summer. Various nitrogen and sugar fractions were determined in the component parts at specified periods of growth stages. Phosphorus deficiency disturbed the nitrogen metabolism at the stages for amide and amino acid formation, which resulted in an accumulation of carbohydrates. The content of total soluble and total nitrogen was higher and that of insoluble nitrogen was lower in summer as compared with winter plants. Of the soluble fractions, the ammonia, amide and nitrate nitrogen were higher and the ‘rest’ nitrogen lower in winter plants. Nitrate formed the highest bulk of the pool of soluble nitrogen in winter, whereas in summer ‘rest’ nitrogen was most abundant. The content of total sugar in winter plants far exceeded that of summer plants, which was wholly due to increase in sucrose content. Glucose was the predominant reducing sugar in both seasons. However, the summer plants were richer in glucose than those from the winter.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of materials science 8 (1989), S. 524-526 
    ISSN: 1573-4811
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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