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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 15 (1993), S. 301-307 
    ISSN: 1432-0789
    Keywords: Mesofauna ; Amino sugar ; Soil micro-flora ; Beech forest ; Moder ; Lime
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In December 1988, litter bags (mesh size: 45 and 1000 μm) were exposed in the organic layer of unlimed and limed moder soil under beech forest in the Solling area of Germany. Bags were retrieved on three sampling dates (May, September, and November 1989) and amounts (g m-2) of glucosamine and galactosamine were determined. Horizon-specific differences generally explained by far the largest part of the treatment variance. In the substrate sampled in December 1988 from the unlimed area glucosamine increased by a factor of 11.8 from the L 1 layer to the H layer and galactosamine by a factor of 15.9. With the exception of the F2 layer, the hexosamine amounts found in the limed substrate sampled in December 1988 were higher in all horizons than in the corresponding horizons sampled from the unlimed area. Exclusion of mesofauna from the 45-μm litter bags generally reduced the level of amino sugars at both sites. The difference between the two mesh sizes was most pronounced in the lowermost horizons (F2 and H) and quite small in the upper horizons. The exclusion of mesofauna significantly increased the glucosamine: galactosamine ratio in the two L layers of the unlimed soil on all sampling dates. Seasonal fluctuations suggested that the actual amino sugar content of the organic layer was essentially the function of two components, the first reflecting long-term accumulation of microbial metabo-lites, and the second reflecting short term fluctuations in the microbial colonization of various C sources together with spatial and temporal differences in the ability of the microflora to produce and to decompose hexosamines. The results of this study show that the mesofauna in the beech forest soils investigated significantly affected both the amino sugar components measured, and thus stimulated the accumulation of one of the most important N pools in forest soils.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Sensitivity to magnetic atoms and low intrinsic absorption characterize the interaction of neutrons with matter. Consequently, polarized neutron reflectivity provides a unique means of performing depth-resolved vector magnetometry. We have used this technique to determine the magnetization depth profiles of Fe/Cr superlattices. Superlattices of bilayer composition [55 A(ring) Fe/17 A(ring) Cr], grown at 523 K, exhibit biquadratic coupling with large saturation fields (∼3 kOe), while those grown at 293 K are ferromagnetically ordered. We have directly measured the evolution of the coupling angle between adjacent Fe layers as a function of applied field and will discuss how bilinear, biquadratic, and external field terms produce the observed order. The weaker coupling found in the Fe/Al system makes possible the investigation of a range of spin configurations at temperatures that do not endanger the sample. We have mapped the phase diagram of a [42 A(ring) Fe/12 A(ring) Al/39 A(ring) Fe] (100) trilayer and find evidence of biquadratic coupling at low temperatures and fields (e.g., when H=180 Oe, the Fe layer spins relax away from ferromagnetic alignment below T≈170 K). Our measurements agree qualitatively with energy minimization calculations and the results of bulk magnetometry.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured the polarized neutron specular reflectivity of superlattices of nominal composition (5.0 nm Fe/1.7 nm Cr) grown by molecular-beam epitaxy. This chromium thickness lies at a minimum of the oscillatory bilinear (180°) coupling parameter, so these films are especially sensitive to biquadratic (90°) terms. One set of films was grown at a substrate temperature of 293 K and another at 593 K. Using neutron reflection, we find that the films grown at 523 K exhibit a 90° magnetic moment rotation between successive Fe layers, while the 293 K films are remanently ferromagnetically ordered in small applied fields (H=1.7 mT). Furthermore, we have observed that films grown at elevated temperature exhibit a larger amount of diffuse x-ray scattering due to conformal roughness than those grown at room temperature. These results suggest that the biquadratic coupling could be induced by the structure of the interfaces. We will also present the field and temperature dependence of the neutron reflectivity from the biquadratic films.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The 2-ML (monolayer) oscillation period has been observed in the magnetization as well as in the magnetoresistance of Fe/Cr/Fe trilayers. Kerr effect measurements were performed in order to verify the periodicity and determine the kind of the coupling between the Fe layers. The magnetoresistance loops show characteristic steps at magnetic field values at which the size of the magnetization changes.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of food quality 15 (1992), S. 0 
    ISSN: 1745-4557
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Tofu was prepared from samples of Amsoy 71 and Vinton or Vinton 81 soybeans grown in different environments. Relationships between soybean, soymilk and tofu protein, lipid, phytic acid, calcium, copper and iron were examined. All components except lipid in soybeans were significantly correlated with the same component in soymilk, but only phytic acid, copper and iron were significantly correlated in soybeans and tofu (moist basis). When relationships were examined on a dry basis, soybean and tofu protein were significantly correlated (r = 0.93).Soybean phytic acid was significantly correlated with tofu calcium (r = 0.90). Tofu calcium and hardness (r = 0.73) and springiness (r = 0.83). were significantly related, and tofu protein was significantly related to fracturability (r = 0.75).The higher-protein varieties (Vinton/Vinton 81) generally produced tofu that had a higher protein content and a firmer, more springy texture than that of the Amsoy 71 beans. Phytic acid may preferentially bind the calcium coagulant, altering the curd structure and the yield, composition and texture of the resulting tofu.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford [u.a.] : International Union of Crystallography (IUCr)
    Acta crystallographica 50 (1994), S. 1256-1258 
    ISSN: 1600-5759
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 167 (1990), S. 757-769 
    ISSN: 1432-1351
    Keywords: Ontogeny ; Auditory fovea ; Tonotopy ; Sexual dimorphism ; Rhinolophus rouxi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This report describes the ontogenesis of tonotopy in the inferior colliculus (IC) of the rufous horseshoe bat (Rhinolophus rouxi). Horseshoe bats are deaf at birth, but consistent tonotopy with a low-to-high frequency gradient from dorsolateral to ventromedial develops from the 2nd up to the 5th week. The representation of the auditory fovea is established in ventro-mediocaudal parts of the IC during the 3rd postnatal week (Fig. 3). Then, a narrow frequency band 5 kHz in width, comprising 16% of the bat's auditory range, captures 50–60 vol% of the IC (Fig. 3c). However, foveal tuning is 10–12 kHz (1/3 octave) lower than in adults; foveal tuning in females (65–68 kHz) is 2–3 kHz higher than in males (62–65 kHz). Thereafter, foveal tuning increases by 1–1.5 kHz per day up to the 5th postnatal week, when the adult hearing range is established (Figs. 4, 5). The increase of sensitivity and of tuning sharpness of single units also follows a low-to-high frequency gradient (Fig. 6). Throughout this development the foveal tuning matches the second harmonic of the echolocation pulses vocalised by these young bats. The results confirm the hypothesis of developmental shifts in the frequency-place code for the foveal high frequency representation in the IC.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 167 (1990), S. 771-784 
    ISSN: 1432-1351
    Keywords: Ontogeny ; Audition ; Vocalisation ; Sensorimotor interaction ; Rhinolophus rouxi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Horseshoe bats (Rhinolophus rouxi) were deafened in their 3rd–5th postnatal week. Subsequently their vocalisations were monitored to evaluate the impact of audition on the development of echolocation pulses. Hearing impairment affected the echolocation pulses as follows: the frequency of the constant frequency (CF) component was altered by between + 4 kHz and − 14 kHz, and the dominance of the second harmonic of the pulses was neutralised by a relative increase in intensity of the first and third harmonics. A second experiment focused on possible influences of acoustical self-stimulation with echolocation pulses on the establishment of auditory fovea representation in the inferior colliculus (IC). Frequency control of echolocation pulses was disrupted by larynx denervation. Thereafter, the bats produced multiharmonic echolocation signals (4–11 harmonics) varying in frequency. IC tonotopy, however, as monitored by stereotaxic electrophysiology, showed the same developmental dynamics as seen in control specimens (Fig. 10). Both experiments indicate that throughout postnatal development echolocation pulses are under auditory feedback control, whereas maturation of the auditory fovea and shifts in its frequency tuning represent an innate process. The significance of this postnatal development might be the adjustment of the vocal motor system of each bat to the frequency of its ‘personal’ auditory fovea.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-1114
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract A new method for the determination of the velocity field with all three velocity components in a light sheet was demonstrated that combines conventional particle tracking anemometry (PTA) with an intensity analysis of the particle flecks. The correlation between intensity and the dimension perpendicular to the light sheet was obtained from the monotonous variation of the laser light intensity across the width of the light sheet.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 98 (1994), S. 234-234 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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