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  • 1
    ISSN: 1435-9456
    Keywords: Key words Armpit effect ; Brood parasites ; Conspecific recognition ; Phenotype matching ; Self-referencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Most birds and mammals learn characteristics of conspecifics from their parents and siblings. In interspecific brood parasites, however, early social learning could lead to species recognition errors because young are reared among heterospecifics. Conceivably, juvenile parasites might inspect and memorize aspects of their own phenotype, and later match features of encountered individuals to that template. We tested for such self-referent phenotype matching by manipulating feather colors of hand-reared fledglings (n = 21) of the parasitic brown-headed cowbird (Molothrus ater). In simultaneous choice trials (n = 6 trials/subject) between dyed and normal-colored adult females, juvenile cowbirds (〈 2 months old) approached more quickly and associated preferentially with individuals that were colored similar to themselves. These preferences remained even when differences between the associative behaviors of juvenile males and females were controlled statistically. Our data imply that cowbirds incorporate their own plumage color into their recognition template. This provides the first evidence of self-referent phenotype matching through experimental manipulation of a recognition cue.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 251 (1973), S. 818-828 
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Zusammenfassung Die Arbeit gibt einen Überblick über das Mäandermodell kondensierter Polymere im amorphen Zustand. In einem ersten Abschnitt wird das Bündelmodell aus nahezu gestreckten Ketten kurz beschrieben und seine Nahordnung mit experimentellen Aussagen verglichen. Danach wird gezeigt, daß Superstrukturen aus enggefalteten Kettenbündeln thermodynamisch stabil sind, wofür in erster Linie die Vertauschungsentropie der Segmentzeilen verantwortlich ist. Die Freie Enthalpie, die Geometrie und der Trägheitsradius mäanderförmig gefalteter Moleküle werden berechnet. Sie sind nur von molekularen Parametern wie Kettenabstand, Kinksegmentlänge und Faltenenergie bestimmt. Alle Resultate stehen in Übereinstimmung mit experimentellen Ergebnissen, einschließlich neuerer Befunde vonPetermann undGleiter (51, 52).
    Notes: Summary This paper gives a survey of the meander model of condensed polymers in their amorphous state. In a first part the bundle model of nearly straight chains is shortly described together with its short range order which agrees with the experimental evidence. Next, superstructures composed of tightly folded bundles are shown to be thermodynamically stable mainly by virtue of the segment-lines interchange entropy. TheGibbs free energy, the geometry and the radius of gyration of meanderlike folded molecules are evaluated. They only depend on molecular parameters like the interchain distance, the length of a kink segment and the energy of a fold. All results are in agreement with experimental evidence including recent reports byPetermann andGleiter (51, 52).
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Rheologica acta 20 (1981), S. 139-154 
    ISSN: 1435-1528
    Keywords: Polypropylene melt ; shear flow ; stress building up ; relaxation ; model theory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Summary A polypropylene melt was exposed to steady and unsteady shear flow in a cone- and -plate-rheogoniometer. The experimentally determined values of shear viscosity and first normal-stress difference were mathematically described with the help of a model theory. The model is of integral-type and based on memory-functions with a set of shear-rate dependent relaxation times (Bogue- and Bogue-White-model). A physical interpretation was given for the relaxation times using the work of Goodeve and Gillespie. For unsteady flow Bogue proposed an averaging mode for the second invariant of the rate of deformation tensor, which is necessary for calculating the relaxation times. In a more recent study the averaging was extended to the relaxation time itself. This step is explained more thoroughly in this paper. The complete set of equations for the stresses in start-up flow, steady flow and stop of shear flow are presented and compared with experimental data. Excellent agreement was obtained for shear-stress build-up and relaxation and the stresses in steady flow. Poor agreement was found between experiment and theory for the build-up and relaxation of the first normal-stress difference. This may be explained either by insufficiencies of the theory or experimental difficulties. Finally, a proposition is made for adopting the theoretical model to steady extensional flow.
    Abstract: Schlüsselwörter Polypropylenschmelze, Scherströmung, Spannungsaufbau, Relaxation, Modelltheorie
    Notes: Zusammenfassung Eine Polypropylenschmelze wurde im Kegel-Platte-Rheometer stationären und instationären Scherbeanspruchungen ausgesetzt. Die Meßwerte der Scherviskosität und der ersten Normalspannungsdifferenz wurden mit Hilfe einer Modelltheorie beschrieben. Diese Modelltheorie ist vom Integraltyp und baut auf Gedächtnisfunktionen mit diskreten deformationsgeschwindigkeitsabhängigen Relaxationszeiten auf (Bogue- und Bogue-White-Modell). Für diese Relaxationszeiten konnte mit Hilfe der Arbeiten von Goodeve und Gillespie eine physikalische Interpretation gegeben werden. Für instationäre Strömungen wurde von Bogue eine Mittelwertsbildung der zweiten Invarianten des Deformationsgeschwindigkeitstensors, der in den Relaxationszeiten enthalten ist, vorgeschlagen. Die Mittelwertbildung wurde in einer neueren Arbeit auf die Relaxationszeit selbst erweitert und erfährt hier eine physikalische Deutung. Die Gleichungen für den Spannungsaufbau, die Spannungen der stationären Scherströmung und der Relaxation der Spannungen wurden für die angeführte Modelltheorie dargestellt und mit den experimentellen Ergebnissen verglichen. Für die stationäre Scherströmung und den Aufbau und die Relaxation der Scherspannung konnte eine ausgezeichnete Übereinstimmung zwischen Rechnung und Experiment erzielt werden. Für den Aufbau und die Relaxation der ersten Normalspannungsdifferenz wurden erhebliche Abweichungen zwischen den Meßwerten und den theoretischen Werten gefunden. Dies kann in der Unzulänglichkeit der Theorie, aber auch im Ablauf des Experimentes begründet sein. Es wurde erläutert, wie die Modelltheorie für stationäre Dehnströmungen eingesetzt werden kann.
    Type of Medium: Electronic Resource
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  • 4
    Publication Date: 2007-12-14
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 5
    Publication Date: 2016-05-12
    Description: Chemical Reviews DOI: 10.1021/acs.chemrev.6b00077
    Print ISSN: 0009-2665
    Electronic ISSN: 1520-6890
    Topics: Chemistry and Pharmacology
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  • 6
    Publication Date: 2014-09-12
    Description: There is growing empirical support for teaching in nonhuman animals. To unravel the evolutionary dynamics of teaching, we need to understand its costs and benefits. In superb fairy-wrens ( Malurus cyaneus ), females teach their embryos by calling to them: embryos learn a vocal password, and hatchlings incorporate the learned vocal password into their begging calls to solicit parental feeding. The more a female teaches (higher call rate), the better the embryos learn (greater call similarity), leading to more food provisioning by parents. Given these direct benefits, we would expect all female fairy-wrens to call often to maximize embryonic learning in their genetic progeny, yet they do not. Teaching the password carries a severe cost: nest predation was higher at both natural and artificial nests that had more incubation calls. At artificial nests, predation was 8-fold higher for high incubation call rate (30 calls per hour) and 5-fold higher for low incubation call rate (15 calls per hour) compared with nests without any incubation calls. At natural nests, nests that were depredated during incubation had higher incubation call rate (18.3 calls per hour) than nests that survived (11.4 calls per hour). Mother fairy-wrens must trade-off the costs of calling and the benefits of learning to optimize fitness benefits of teaching.
    Print ISSN: 1045-2249
    Electronic ISSN: 1465-7279
    Topics: Biology
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  • 7
    Publication Date: 2018-03-06
    Description: By definition, teaching is both cooperative and costly and so we appreciate Cordony’s (2017) commentary in this spirit. We also agree that the cost of teaching in the superb fairy-wren ( Malurus cyaneus ) system can and should be more fully explored. Kleindorfer, Hoi, et al. (2014) quantified a cost of incubation calling ( Colombelli-Négrel et al. 2012 ) to fairy-wren mothers through the detection of higher egg predation at nests with more incubation calls. The commentary raises 2 main concerns: that 1) Kleindorfer, Hoi, et al. (2014) misinterpreted the operational definition of cost in animal teaching by Caro and Hauser (1992) and its operational interpretation by Thornton and Raihani (2010) , because 2) nest predation is neither an immediate nor a personal cost to the mother.
    Print ISSN: 1045-2249
    Electronic ISSN: 1465-7279
    Topics: Biology
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  • 8
    Publication Date: 2017-08-04
    Description: Coloration mediates the relationship between an organism and its environment in important ways, including social signaling, antipredator defenses, parasitic exploitation, thermoregulation, and protection from ultraviolet light, microbes, and abrasion. Methodological breakthroughs are accelerating knowledge of the processes underlying both the production of animal coloration and its perception, experiments are advancing understanding of mechanism and function, and measurements of color collected noninvasively and at a global scale are opening windows to evolutionary dynamics more generally. Here we provide a roadmap of these advances and identify hitherto unrecognized challenges for this multi- and interdisciplinary field.
    Keywords: Anatomy, Morphology, Biomechanics, Online Only
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
  • 10
    Publication Date: 2010-06-06
    Print ISSN: 0025-3162
    Electronic ISSN: 1432-1793
    Topics: Biology
    Published by Springer
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