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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 22 (1966), S. 648-649 
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Zusammenfassung Bei den tuberkulösen Meerschweinchen wurde in der Niere eine erhöhte Aktivität der Glukose-6-Phosphatase beobachtet. Isoniazid hat die erhöhte Aktivität des Enzyms nicht erniedrigt, wenn es tuberkulösen Tieren vom 8. bis zum 38. Tage nach der Infektion oral verabreicht wurde. Es wird angenommen, dass die erhöhte Aktivität Ausdruck der Adaptionsfähigkeit von Glukose-6-Phosphatase ist.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 58 (1983), S. 415-417 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The experiments on Eucalyptus trees reported here demonstrate that allelopathic effects can be mediated by insects grazing on foliage. We show that the allelochemical nature of insect frass suppresses germination, growth and survival of herb layer species, that plant species vary in their tolerance of this material, and that as a result, the structure and composition of associated, herbaceous understory plant communities are markedly affected by frass fall.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 112 (1997), S. 179-186 
    ISSN: 1432-1939
    Keywords: Key wordsPlutella xylostella ; Population density ; Oviposition preference ; Population dynamics ; Diet breadth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Although ecological specialists exploit a relatively limited resource base, it is unclear whether specialization limits local population density. Here, we focus on the relationship between diet specialization and local population density of a phytophagous insect, the diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae). We compared key life history traits and food plant use among five pairs of high- and low-density populations from widely separate geographical areas. Moths from populations that persist at high densities were more generalized in food plant use than moths from low-density populations. In particular, the oviposition preference and larval performance of moths from some high-density populations were less variable across a suite of food plants, suggesting that moths from high- density populations had a broader diet. In addition, low- density populations were less similar to each other, exhibiting opposing preferences for particular plant species. Hence diet breadth may explain some of the persistent differences in the population density of diamondback moths in the field, consistent with the idea that ecological specialization may be generally associated with population density.
    Type of Medium: Electronic Resource
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 67 (1985), S. 118-120 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our previously published experiments on allelopathic effects of insect frass in Eucalyptus communities (Silander et al. 1983) have been criticized on the grounds that our estimates of annual frass production were exscessive (Ohmart 1985). However, we spanned the entire array of estimates of frass fall available from eucalypt communities, and we demonstrated allelopathic effects at even the lowest levels suggested by Ohmart. We suggest that average values of frass fall per hectare are irrelevant because they ignore both large scale variation among sites in time and space, and small scale variation in patchiness of frass accumulation. At the ecological scales relevant to germinating seeds, frass concentrations in local pockets may be considerably higher than the averages calculated for the entire ground surface.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-1939
    Keywords: Specialization ; Herbivores ; Parasitoids ; Enemy-free space
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The pressure to escape natural enemies may shape how herbivorous insects use their plant resources. On wild crucifers, ovipositional preferences of the diamondback moth (Plutella xylostella; DBM) were similar to searching preferences of its main parasitoid, an ichneumonid wasp (Diadegma insulare). But on cultivated crucifers, these species had opposite preferences. In addition, DBM ovipositional preferences did not correlate with growth or reproduction on several foodplants. We interpret these patterns as evidence of evolution for use of enemy-free space in agricultural systems.
    Type of Medium: Electronic Resource
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 80 (1989), S. 211-214 
    ISSN: 1432-1939
    Keywords: Pieris rapae ; Nitrogen ; Brassica ; Insect-plant interactions ; Nutritional ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To test the prediction that P. rapae egg densities increase with N fertilizer in large-scale systems as they do in model systems with potted plants, we used field experiments with Brassica oleracea var. acephala L. (collards and kale) planted in pots or large field plots, and treated with different levels of nitrogen fertilizer. In small-scale field experiments with potted kale and collards, egg densities were significantly higher on plants with high N than those with low N. But in larger scale experiments with field-grown collards, average seasonal P. rapae egg densities were not significantly correlated with leaf N content. These differences among experiments did not depend on the magnitude of the difference in foliage N levels.
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Planta 135 (1977), S. 217-223 
    ISSN: 1432-2048
    Keywords: Killer ; Phytochrome ; Pisum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract “Killer”, a substance extracted from stem tissue of etiolated pea seedlings (Pisum sativum L. v. Alaska), interacts specifically with the far-red-absorbing form of phytochrome (Pfr) in vitro in a temperature-independent, rapid, stoichiometric fashion to cause a loss of phytochrome photoreversibility. The chromatographic, solubility, and spectral properties of partially purified fractions indicate that Killer is a cyclic, unsaturated molecule containing ionizible hydroxyl groups; its molecular weight is unknown, although probably low. Possible mechanisms by which the Killer-phytochrome interaction results in the loss of photoreversibility are discussed.
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Journal of low temperature physics 34 (1979), S. 17-31 
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: We examine the anatomy of the quantitative properties of thermal transport across a solid-liquid boundary as it is described by acoustic mismatch theory. The single parameter, the Kapitza resistance, is a function of four loss parameters and one thermal transport parameter, the thermal diffusivity of the fluid. The loss parameters are to be determined from the dispersion relations for phonons at the peak of the thermal excitation in the material. The temperature dependence of the Kapitza resistance depends on the variation of the phonon excitation in the material with temperature, the familiar temperature-cubed factor, and the variation of the loss factors with temperature and frequency for phonons at the thermal peak, and the variation of the diffusivity with temperature. Since these parameters are undetermined and experimentally rather inaccessible, we conclude that for the present the Kapitza resistance must be viewed as a technological heat transport parameter. Some discussion is given of the part played by second sound in helium II in the surface heat transport process.
    Type of Medium: Electronic Resource
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  • 19
    ISSN: 1572-9125
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Methods of interval mathematics are used to find upper and lower bounds for the solution of two-point boundary-value problems at discrete mesh points. They include interval versions of shooting and of finite-difference techniques for linear and non-linear differential equations of second order, and of finite-difference methods for Sturm-Liouville eigenvalue problems. Good results are obtained whenever the difficulties of dependency-width can be avoided, and particularly for the finite-difference method when the associated matrix is anM matrix.
    Type of Medium: Electronic Resource
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