6,392 research outputs found

    Seven zero nine zero computer program for determination of precision lattice constants

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    Computer program for calculation of lattice parameters for cubic, tetragonal, and hexagonal crystals - magnesium oxide and aluminum oxid

    XTH acts at the microfibril-matrix interface during cell elongation

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    Sulphorhodamine-labelled oligosaccharides of xyloglucan are incorporated into the cell wall of Arabidopsis and tobacco roots, and of cultured Nicotiana tabacum cells by the transglucosylase (XET) action of XTHs. In the cell wall of diffusely growing cells, the subcellular pattern of XET action revealed a 'fibrillar' pattern, different from the xyloglucan localization. The fibrillar fluorescence pattern had no net orientation in spherical cultured cells. It changed to transverse to the long axis when the cells started to elongate, a feature mirroring the rearrangements of cortical microtubules and the accompanying cellulose deposition. Interference with the polymerization of microtubules and with cellulose deposition inhibited this strong and 'fibrillar'-organized XET-action, whereas interference with actin-polymerization only decreased the intensity of enzyme action. Epidermal cells of a mutant with reduced cellulose synthesis also had low XET action. Root hairs (tip-growing cells) exhibited high XET-action over all their length, but lacked the specific parallel pattern. In both diffuse- and tip-growing cell types extraction of the incorporated fluorescent xyloglucans by a xyloglucan-specific endoglucanase reduced the fluorescence, but the 'fibrillar' appearance in diffuse growing cells was not eliminated. These results show that XTHs act on the xyloglucans attached to cellulose microfibrils. After incorporation of the fluorescent oligosaccharides, the xyloglucans decorate the cellulose microfibrils and become inaccessible to hydrolytic enzymes

    Erprobung und Bewertung eines neuen Geräts zur Unterstockpflege (SIEGWALD HS 1200) im ökologischen Weinbau

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    A new system for under-vine cultivation (SIEGWALD HS 1200) was tested over a period of two years in four farms with organic viticulture and compared with their customary systems. The SIEGWALD system has well proved its worth. The total costs were comparable to those of other systems. All tractors met the requirements of the SIEGWALD system. Vine trunks were not injured, except in one vineyard. Negative consequences for the fauna on the soil surface and for predatory mites (Typhlodromus pyri) in the canopy were not found

    Price Elasticity of Demand for Term Life Insurance and Adverse Selection

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    This paper provides an empirical estimate of price' and risk' elasticities of demand for term life insurance for those who purchase some insurance. It finds that the elasticity with respect to changes in premiums is generally higher than the elasticity with respect to changes in risk. It also finds that the elasticity, in the range of -0.3 to -0.5, is sufficiently low that adverse selection in term life insurance is unlikely to lead to a death spiral and may not even lead to measured effects of adverse selection on total purchases.

    First measurements of the index of refraction of gases for lithium atomic waves

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    We report here the first measurements of the index of refraction of gases for lithium waves. Using an atom interferometer, we have measured the real and imaginary part of the index of refraction nn for argon, krypton and xenon, as a function of the gas density for several velocities of the lithium beam. The linear dependence of (n1)(n-1) with the gas density is well verified. The total collision cross-section deduced from the imaginary part is in very good agreement with traditional measurements of this quantity. Finally, as predicted by theory, the real and imaginary parts of (n1)(n-1) and their ratio ρ\rho exhibit glory oscillations

    The Flash Pattern of Photosynthetic Oxygen Evolution after Treatment with Low Concentrations of Hydroxylamine as a Function of the Previous S1/S0-Ratio Further Evidence that NH2OH Reduces the Water Oxidizing Complex in the Dark

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    Flash induced oxygen evolution patterns of isolated PS II complexes from the cyanobacterium Synechococcus were measured with a Joliot-type electrode. By suitable preflash and dark adaptation procedures, samples were prepared in the state S1 (100%), as well as enriched in S0 (60% S0, 40% S,). After treatment with low concentrations of NH2OH (≤ 100 μм), the two flash patterns were identical. This is further evidence for a reduction of the water oxidizing complex by hydroxylamine in the dark. Two reduced states (S-1 and S-2) below S0 are formed by this reduction
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