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  • 1
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    Schnellverfahren zur jodometrischen Bestimmung des Wasserstoffgehaltes organischer Verbindungen (1967)
    Springer
    Details
    Publication Date: 1967-09-01
    Print ISSN: 0026-3672
    Electronic ISSN: 1436-5073
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 2
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    Untersuchungen �ber die quantitative Umsetzung des organischen Wasserstoffes in Schwefels�ure (1967)
    Springer
    Details
    Publication Date: 1967-09-01
    Print ISSN: 0026-3672
    Electronic ISSN: 1436-5073
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 3
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    Bifurcation Analysis of a Class of Parametrized Two-Point Boundary Value Problems (2000)
    Springer
    Details
    Publication Date: 2000-10-01
    Print ISSN: 0938-8974
    Electronic ISSN: 1432-1467
    Topics: Mathematics , Physics
    Published by Springer
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  • 4
    Electronic Resource
    Electronic Resource
    Ein Hochdruck-Kapillarviskosimeter mit elektronischer Druckmessung (1964)
    Springer
    Rheologica acta 3 (1964), S. 244-249 
    Details
    ISSN: 1435-1528
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Zusammenfassung Die Konstruktion eines neuen Hochdruck-Kapillarviskosimeters wird beschrieben. Die Druckmessung erfolgt elektronisch direkt an der Meßflüssigkeit. Das Lösen von Druckgas in der Meßflüssigkeit wird verhindert. Durch Temperaturfühler vor und nach der Kapillare können Erwärmungseffekte verfolgt werden. Weitere Verbesserungsmöglichkeiten werden besprochen und einige Messungen mitgeteilt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02096157
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of wheat resistance, the parasitoid Aphidius rhopalosiphi, and the entomopathogenic fungus Pandora neoaphidis, on population dynamics of the cereal aphid Sitobion avenae (2000)
    Springer
    Entomologia experimentalis et applicata 97 (2000), S. 109-114 
    Details
    ISSN: 1570-7458
    Keywords: Sitobion avenae ; Aphidius rhopalosiphi ; Pandora neoaphidis ; Entomophthorales ; tritrophic effects ; wheat resistance ; natural enemies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The influence of wheat (Triticum aestivumL.) resistance, the parasitoid Aphidius rhopalosiphiDe Stephani-Perez (Hymenoptera: Braconidae) and the entomopathogenic fungus Pandora neoaphidis(Remaudière et Hennebert) Humber (Zygomycetes: Entomophthorales) on the density and population growth rate of the cereal aphid Sitobion avenae(F.) (Hemiptera: Aphididae) was studied under laboratory conditions. Partial wheat resistance was based on hydroxamic acids, a family of secondary metabolites characteristic of several cultivated cereals. The partial resistance of wheat cultivar Naofén, the action of the parasitoid and the joint action of the parasitoid and fungus, reduced aphid density. The lowest aphid densities were obtained with the combination of the parasitoid and the fungus, but wheat resistance under these circumstances did not improve aphid control. Significant reductions of population growth rate (PGR) of aphids were obtained with the joint action of wheat resistance and natural enemies. In particular, the combined effects of parasitoids and fungi showed significantly lower PGR than the control without natural enemies in both wheat cultivars. Our results support the hypothesis that wheat resistance and the utilization of biological control agents could be complementary strategies in an integrated pest management program against cereal aphids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004048600899
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  • 6
    Electronic Resource
    Electronic Resource
    The Influence of Previous Experience and Starvation on Aphid Feeding Behavior (2000)
    Springer
    Journal of insect behavior 13 (2000), S. 699-709 
    Details
    ISSN: 1572-8889
    Keywords: feeding behavior ; previous experience ; starvation ; stylet ; xylem ingestion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It was hypothesized that (1) previous experience of aphids on a host plant leads to differences in their feeding behavior relative to aphids without previous experience on it and that (2) a change in the physiological state of the aphid modifies their experience-induced behavior. Using electronic recording, the feeding behavior of the aphid Sitobion fragariae (Walker) on wheat Triticum aestivum L. and oat Avena sativa L. was examined, comparing aphids with or without previous experience on a given host and with or without a period of starvation before assessing probing behavior. All comparisons were performed within a single aphid clone to minimize the effect of genetic variation. Feeding behavior on wheat was significantly affected by previous experience and starvation. The effect of previous experience interacted with the host plant where feeding behavior was tested. Aphids feeding on wheat following previous experience on wheat showed a longer time and a higher number of pathway activities and less time in waveform F (i.e., mechanical stylet work and penetration difficulties) than did aphids feeding on wheat after a previous experience on oat. No differences in the time from the beginning of the recording until the first salivation into the sieve elements were found. When aphids were subjected to a period of starvation, the time devoted to xylem ingestion increased compared with that of nonconstrained aphids. These results are discussed in terms of factors affecting foraging decisions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007844027368
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  • 7
    Electronic Resource
    Electronic Resource
    Untersuchungen über die quantitative Umsetzung des organischen Wasserstoffes in Schwefelsäure (1967)
    Springer
    Microchimica acta 55 (1967), S. 872-884 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A volumetric procedure has been described for determining the hydrogen content of organic compounds in the form of sulfuric acid. The combustions were conducted in the presence of sulfur, sulfur dioxide, or carbon disulfide in an oxygen atmosphere. Sulfur dioxide is oxidized to sulfur trioxide on a platinum catalyst in the combustion tube, and the water resulting from the combustion combines with the sulfur trioxide formed to yield concentrated sulfuric acid. This condenses in an absorption vessel attached to the combustion tube. Any excess sulfur trioxide is expelled from the oleum during the purging period by warming. After the absorber has been swept out, the sulfuric acid equivalent to the hydrogen content of the samples is titrated acidimetrically.
    Abstract: Résumé On présente une méthode volumétrique pour déterminer la teneur en hydrogène de composés organiques, sous forme d'acide sulfurique. Les combustions s'effectuent en présence de soufre, d'anhydride sulfureux ou de sulfure de carbone en atmosphère d'oxygène. L'anhydride sulfureux est oxydé en anhydride sulfurique sur catalyseur au platine placé dans le tube à combustion. Il se forme ensuite de l'acide sulfurique concentré au contact de l'eau produite par la combustion. Celle-ci se condense dans un récipient pour absorption relié au tube à combustion. On chasse l'anhydride sulfurique en excès de l'oléum pendant la période de balayage, par échauffement. Après balayage de l'absorbeur on titre par acidimétrie l'acide sulfurique équivalent à la teneur en hydrogène de l'échantillon.
    Notes: Zusammenfassung Eine volumetrische Methode zur Bestimmung des Wasserstoffgehaltes organischer Verbindungen in Form von Schwefelsäure wird dargelegt. Die Verbrennungen werden in Gegenwart von Schwefel, Schwefeldioxid oder Schwefelkohlenstoff in Sauerstoffatmosphäre durchgeführt. Das Schwefeldioxid wird an dem im Verbrennungsrohr untergebrachten Platinkatalysator zu Schwefeltrioxid oxydiert, das mit dem bei der Verbrennung entstandenen Wasser konz. Schwefelsäure bildet. Diese kondensiert in einem dem Verbrennungsrohr angeschlossenen Absorptionsgefäß. Das überschüssige Schwefeltrioxid vertreibt man aus dem Oleum im Laufe der Spülungsperiode durch Erwärmen. Nach der Ausspülung des Absorbers wird die dem Wasserstoffgehalt der Proben äquivalente Schwefelsäure acidimetrisch titriert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01216830
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  • 8
    Electronic Resource
    Electronic Resource
    Schnellverfahren zur jodometrischen Bestimmung des Wasserstoffgehaltes organischer Verbindungen (1967)
    Springer
    Microchimica acta 55 (1967), S. 920-928 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A new method for the iodometric determination of the hydrogen content of organic materials has been described. The sample is mixed with powdered sulfur and decomposed at 1200° C in a stream of nitrogen over quartz wool or a platinum-quartz wool catalyst. The sulfur-bearing pyrolysis products yield hydrogen sulfide that is then, absorbed in a zinc sulfate-sodium acetate solution and titrated iodometrically. The optimal reaction conditions were thoroughly studied and also explained from the theoretical standpoint.
    Notes: Zusammenfassung Eine neue Methode zur jodometrischen Bestimmung des Wasserstoffgehaltes organischer Verbindungen wird beschrieben. Die Probe wird mit Schwefelpulver vermischt und bei 1200° C im Stickstoff strom über Quarzwolle oder einem Platin- Quarzwollekatalysator zersetzt. Aus den schwefelhaltigen Pyrolyseprodukten bildet sich Schwefelwasserstoff, der in einer Zinksulfat-Natriumacetatlösung absorbiert und jodometrisch titriert wird. Die optimalen Reaktionsbedingungen wurden eingehend untersucht und auch in theoretischer Hinsicht erklärt.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01216837
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  • 9
    Electronic Resource
    Electronic Resource
    Expression of stylar incompatibility in the Andean clonal tuber crop oca (Oxalis tuberosa Mol., Oxalidaceae) (2000)
    Springer
    Sexual plant reproduction 13 (2000), S. 105-111 
    Details
    ISSN: 1432-2145
    Keywords: Key words Oca ; Oxalis tuberosa ; Floral heteromorphy ; Self-incompatibility ; Pollen fertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  Long-, mid-, and short-styled clonal accessions of oca (Oxalis tuberosa) were intercrossed in a complete diallelic design. Pollen tube growth in styles was monitored in all diallelic crosses. Pollen fertility was estimated by two tests: staining of pollen grains with aceto-carmine and detection of β-galactosidase activity by the substrate X-Gal. The two methods of pollen fertility estimation were equally useful to detect fertility levels. Pollen originating from short stamens had the highest fertility (85%) and pollen from long stamens had the lowest fertility (70%). Pollen fertility was high throughout, but its degree varied with the stylar morph on which the pollen was formed. Long-styled accessions had the highest rates of fertile pollen. Differences in pollen fertility at different anther levels in the same style morph were also apparent. Pollen grain diameter of the six morph-anther level combinations was inversely correlated with pollen fertility. Pollen grains from long stamens were the largest and pollen grains from short stamens were the smallest. Neither pollen fertility nor pollen grain size had an influence on pollen tube growth in the style or on fruit and seed set. Pollen tubes growing within the styles were inhibited at a different level for each of the 18 cross combinations in the diallel. Although legitimate crosses had greatest pollen tube growth, some of the illegitimate inter- and intramorph crosses had equally high scores. Of all illegitimate crosses, mid-styled seed parents had the lowest level of stylar incompatibility. Fruit and seed set were highly correlated with the extent of pollen tube growth in the style. The number of pollen tubes entering ovules in a flower was in good agreement with the number of seeds produced per fruit. Therefore, it is concluded that stylar incompatibility is the major determinant of limited seed formation in oca even in the most successful legitimate cross combinations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004970000040
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  • 10
    Electronic Resource
    Electronic Resource
    Bifurcation Analysis of a Class of Parametrized Two-Point Boundary Value Problems (2000)
    Springer
    Journal of nonlinear science 10 (2000), S. 507-531 
    Details
    ISSN: 1432-1467
    Keywords: Key words. bifurcation, equivariance, nonlinear boundary value problem, shell equations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Summary. In this paper, we study the solution manifold M of a class of nonlinear parametrized two-point boundary value problems. Typical representatives of this class are the shell equations of Bauer, Reiss, Keller [2] and Troger, Steindl [29]. The boundary value problems are formulated as an abstract operator equation T(x,λ)=0 in appropriate Banach spaces. By exploiting the equivariance of T , we obtain detailed information about the structure of M. Moreover, we show how these theoretical results can be used to compute efficiently interesting parts of M with numerical standard techniques. Finally, we present numerical results for the shell equations given in [2] and [29].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003320010004
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