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  • Hemocytes  (2)
  • Key words Insect herbivory  (1)
  • NaX-zeolite catalyst  (1)
  • AERODYNAMICS
  • Springer  (4)
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  • Springer  (4)
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  • 1
    ISSN: 1432-1939
    Keywords: Key words Insect herbivory ; Host-plant density ; Perennial weed ; Biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper contributes to the relatively sparse literature on the effects of insect herbivory on the population dynamics of plants and is probably unique in that it reports the long-term effects of combinations of three insect herbivore species on the population densities of a moderately long-lived tree species. The tree is Sesbania punicea, a leguminous perennial from South America that has been the target of a biological control programme in South Africa for almost 20 years. Sixteen infestations of the weed have been monitored for periods of up to 10 years to determine changes in the density of the mature, reproductive plants under the influence of different combinations of three biological control agents (i.e. with one, two or three of the agent species present in the weed infestation). The three biological control agents, all weevil species, include Trichapion lativentre, which primarily destroys the flower-buds, Rhyssomatus marginatus, which destroys the developing seeds, and Neodiplogrammus quadrivittatus, whose larvae bore into the trunk and stems of the plants. While T. lativentre occurs throughout the range of the weed in South Africa, the other two species are less mobile, more recent introductions and are largely confined to the vicinity of selected release sites. There has been a significant decline in the density of mature S. punicea in areas where two or more of the agents are established. The decline of the weed has been most evident where N. quadrivittatus is active and particularly so where both of the other two weevil species are also present.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of thermal analysis and calorimetry 38 (1992), S. 739-748 
    ISSN: 1572-8943
    Keywords: kinetic analysis ; NaX-zeolite catalyst ; surface reactions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Mit Modellrechnungen für eine irreversible Oberflächenreaktion 1. Ordnung konnte gezeigt werden, daß durch Anwendung der Methode der Variation der Heizgeschwindigkeit auf die Desorptionskurve des Ausgangsstoffes die näherungsweise Bestimmung der Aktivierungsenergie der Desorption des Ausgangsstoffes bzw. der Oberflächenreaktion möglich ist, je nachdem ob das Verhältnis der Aktivierungsenergien für die Oberflächenreaktion und der Desorption des Ausgangsstoffes größer oder kleiner als eins ist. Die Möglichkeiten der kinetischen Auswertung werden auf die isomerisierung von Cyclopropan an einem NaX-Zeoliten angewendet. Die erhaltene Adsorptionswärme für Cyclopropan und die Aktivierungsenergie für die Reaktion stimmen gut mit Literatur-werten von isothermen Messungen im Impulsreaktor überein.
    Notes: Abstract By means of model calculations it could be shown for an irreversible surface reaction of 1st order that the determination of the activation energy of the desorption of the reactant or, respectively, of the surface reaction is possible by application of the method of variation of the heating rate to the desorption curve of the reactant, according to circumstances whether the ratio of the activation energy of the surface reaction and of the desorption of the reactant is greater or smaller than one. The possibilities of the kinetic evaluation are applied to the isomerization of cyclopropane on a NaX-zeolite catalyst. The resulting heat of adsorption of cyclopropane and the activation energy of the reaction agree well with the values of literature obtained by isothermal measurements in a pulse reactor.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0878
    Keywords: Insect ; Hemocytes ; Capsules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sterile fragments of cellophane, cat-gut, cotton, or beef muscle implanted into the body cavity of Locusta migratoria and Melolontha melolontha are immediately surrounded by granular hemocytes which form a multi-layered capsule around each foreign body. The cytoplasm of the granular hemocytes of the outer zone of the capsule in both species shows an accumulation of fibrous material (microtubules and microfilaments). None of the implanted material appeared to be degraded.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 162 (1975), S. 343-348 
    ISSN: 1432-0878
    Keywords: Insects ; Hemocytes ; Capsules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Of the three hemocyte types present in the blood of Calliphora, only one participates in capsule formation around implanted cellophane. This hemocyte, the thrombocytoid, shows in the blood a tendency to dissociate into numerous small cytoplasmic fragments, comparable to the mammalian megakaryocyte. This tendency is dramatically increased during the process of encapsulation. Most of the intact thrombocytoids and the numerous fragments participating in capsule formation do not show any particular modifications in their cytoplasm during this process, which corresponds to a mere sequestration of the implant. Dense material, resulting from necrotic cell debris and hemolymph lipoproteins, is often observed between the cellophane and encapsulating thrombocytoids, which apparently participate in the resorption of this material.
    Type of Medium: Electronic Resource
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