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  • Messor barbarus  (3)
  • Polymer and Materials Science  (3)
  • 5-methoxyindoleamines  (1)
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Materialart
Erscheinungszeitraum
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Separation and o-phthaldehyde fluorometric determination of 5-hydroxy- and 5-methoxyindoleamines by thin-layer chromatography: Selected applications
    Amsterdam : Elsevier
    Analytical Biochemistry 174 (1988), S. 275-279 
    Details
    ISSN: 0003-2697
    Schlagwort(e): 5-hydroxyindoleamines ; 5-methoxyindoleamines ; fluorescence ; platelets ; thin-layer chromatography
    Quelle: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Thema: Biologie , Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1016/0003-2697(88)90546-5
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Responses of the trunk routes of a harvester ant to plant density (1993)
    Springer
    Oecologia 93 (1993), S. 109-113 
    Details
    ISSN: 1432-1939
    Schlagwort(e): Trunk routes ; Harvester ants ; Phalanx ; Guerilla ; Messor barbarus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Messor barbarus is a Mediterranean harvester ant that constructs physically defined trunk routes on the ground to connect nest entrances with foraging areas. Some responses of these trunk routes to plant density (and therefore resource abundance) were analyzed by testing the preferential allocation of different parts (trunk route ends, segments and branching points) in a patchy environment. Maps of grass density in four categories and Messor barbarus trunk routes were compiled for a Mediterranean pasture in Central Spain over four consecutive years. The proportions of the density categories in each year were used to calculate random expected frequencies of the trunk route points and the predominance of higher or lower grass densities. Trunk route ends discriminate and selectively reach patches with a greater abundance of resources in all study years. Branching points are also allocated preferentially in areas with higher vegetation density, but only in years with a predominance of the higher categories of grass density. In these years, the colonies of Messor barbarus have a “phalanx” strategy at a colonial level, and branching is more profuse. Finally, trunk route segments do not indicate any preference for crossing determined vegetation densities, but rather connect successive branching points or trunk route ends by the shortest route. These results concur with a model of structural strategy change (“guerilla” — “phalanx”) (Hutchings 1988) at the level of trunk routes. They are probably constituted by “transitory” sections with few branches, that expand other more profusely branched sections which are more dedicated to foraging.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00321199
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  • 3
    Digitale Medien
    Digitale Medien
    Asymmetric interactions between plants and seed-harvesting ants in a Mediterranean pasture (2000)
    Springer
    Ecological research 15 (2000), S. 449-452 
    Details
    ISSN: 1440-1703
    Schlagwort(e): asymmetric interactions ; foraging strategies ; Messor barbarus ; seed-harvesting ants ; vegetation dynamics
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: A four-year study on the interactions between plants and seed-harvesting ants in a Mediterranean pasture is reviewed in this paper. As previously reported in many studies on plant–herbivore interactions, ant–plant relationships are also asymmetric; plants had a larger impact on herbivore dynamics than vice versa. However, the asymmetry did not refer to population dynamics but rather to animal foraging strategies. Ants did not exert a significant influence on vegetation dynamics in terms of plant abundance. The main constraints underlying vegetation change were self-regulation and rainfall. In contrast, the structural characteristics and abundance of vegetation had a significant impact on several important features of food harvesting by ants. This influence was not only associated with their feeding requirements but also with their foraging activities.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1046/j.1440-1703.2000.00364.x
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  • 4
    Digitale Medien
    Digitale Medien
    Temperature-vegetation structure interaction: the effect on the activity of the ant Messor barbarus (L.) (1992)
    Springer
    Plant ecology 99-100 (1992), S. 119-128 
    Details
    ISSN: 1573-5052
    Schlagwort(e): Microclimate ; Canopy type ; Evergreen oak ecosystem ; Colony activity ; Ants ; Messor barbarus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Several canopy types in an evergreen oak forest with open pastures have been used to examine climatic features of this system related to temperature. Circadian variation in temperature seems to be related to structural characteristics of the vegetation, with an apparent influence of the plant micro- and meso-environments analyzed. The activity of a population of granivorous ants (Messor barbarus (L.)), studied in the same area, showed a clear dependence on ambient temperature, but, although the colonies were always inside one of the vegetation types, there was no significant relationship between the activity of ants and grasscover. This, together with other observations, indicates that the possible controlling effect of the vegetation is limited by the tolerance of ants (when faced with adverse conditions) during each daily foraging period.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00118217
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  • 5
    Digitale Medien
    Digitale Medien
    Alternative synthetic strategies for Schiff base derived liquid crystal polymers: A comparative study (1996)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2603-2611 
    Details
    ISSN: 0887-624X
    Schlagwort(e): liquid crystal polymers ; polyazomethines ; polyethers ; polyesters ; nematic ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Semiflexible liquid crystalline polymers based on Schiff bases as mesogenic cores have been synthesized through different synthetic strategies. The mesogenic cores are derived from 1,5-naphthalenediamine linked to a polymethylenic spacer by means of ether or ester groups. The synthetic strategies differ in the disconnection of the molecules to design the synthesis of the repeating units. Polymers were synthesized either as polyazomethines, where imine bonds are formed in the polymer synthesis, or as polyethers or polyesters, where the ether or ester groups are formed at the polymer-forming stage. The influence of the synthetic method and the linking groups between mesogenic core and flexible spacer on the thermal and mesogenic properties has been analyzed by DSC, thermogravimetry, and optical microscopy. The possibility of obtaining hydroxy-functionalized polymers by different synthetic strategies has been studied as well as the influence of these groups on the thermal and mesogenic properties. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Kinetic investigations on the photopolymerization of di- and tetrafunctional methacrylic monomers in polymeric matrices. ESR and calorimetric studies. II. Postpolymerization reactions (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2785-2791 
    Details
    ISSN: 0887-624X
    Schlagwort(e): postpolymerization reactions ; ESR ; polymeric matrices termination reactions ; H-transfer reactions ; kinetic constants ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction kinetics in the dark of photopolymerized mono- and dimethacrylates in a polymeric binder has been studied. Electron spin resonance spectroscopy (ESR) provided useful information regarding the nature of the radicals involved in postpolymerization reactions. Computer simulations were performed to study the decay of the propagating radicals by considering normal bimolecular termination and transfer reactions of the radicals to the binder. Differences were found in the termination reactions for mono- and difunctional monomers when they were photopolymerized in a solid medium. Absolute kinetic constants for H-transfer reaction with the binder, relative kinetic rate constants for radical-radical coupling, and average lifetimes for the radicals have been calculated. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2785-2791, 1998
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Kinetic investigations on the photopolymerization of di- and tetrafunctional (meth)acrylic monomers in polymeric matrices. ESR and calorimetric studies. I. Reactions under irradiation (1998)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 36 (1998), S. 2775-2783 
    Details
    ISSN: 0887-624X
    Schlagwort(e): photopolymerization kinetics ; ESR ; polymeric binders ; radical environment ; photocalorimetry ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The photopolymerization of several di- and tetrafunctional (meth)acrylic monomers in the presence of a styrene-butadiene-styrene polymeric matrix (SBS) has been studied. Electron spin resonance spectroscopy (ESR) and differential scanning photocalorimetry (photo-DSC) were used as monitoring techniques to identify the photogenerated radicals and analyze photopolymerization profiles, radical environments, and radical secondary reactions. The study of the photopolymerization and/or photocrosslinking reactions of these monomers in the solid media was carried out by taking into consideration different factors, such as the influence of both monomer and photoinitiator structures on the hydrogen abstraction in the binder with formation of benzylic and allylic radicals, the polymerization of the monomers itself and the hydrogen abstraction reaction in the polymerized acrylic chains. Finally, irradiation of the system SBS/photoinitiator in the absence of monomer was also accomplished. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2775-2783, 1998
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
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