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  • Articles  (10)
  • Clamator glandarius  (6)
  • Industrial Chemistry and Chemical Engineering  (4)
  • 1995-1999  (10)
  • 1960-1964
  • 1
    ISSN: 1432-1939
    Keywords: Key words Brood parasitism ; Clamator glandarius ; Coevolution ; Parasite counter-defences ; Pica pica
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A long-term study of the interactions between a brood parasite, the great spotted cuckoo Clamator glandarius, and its primary host the magpie Pica pica, demonstrated local changes in the distribution of both magpies and cuckoos and a rapid increase of rejection of both mimetic and non-mimetic model eggs by the host. In rich areas, magpies improved three of their defensive mechanisms: nest density and breeding synchrony increased dramatically and rejection rate of cuckoo eggs increased more slowly. A stepwise multiple regression analysis showed that parasitism rate decreased as host density increased and cuckoo density decreased. A logistic regression analysis indicated that the probability of changes in magpie nest density in the study plots was significantly affected by the density of magpie nests during the previous year (positively) and the rejection rate of mimetic model eggs (negatively). These results are consistent with a hypothesis (the intermittent arms race hypothesis) of spatially structured cyclic changes in parasitism. During periods of parasitism, host defences continuously improve, and as a consequence, the fitness gains for parasites decrease. When host defences against parasites reach a high level, dispersing parasites have a selective advantage if they are able to emigrate to areas of low resistance. Once parasites have left an area hosts will lose their defensive adaptations due to their cost in the absence of parasitism. The scene is then set for re-colonization by great spotted cuckoos.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1939
    Keywords: Key words Brood parasitism ; Clamator glandarius ; Egg laying ; Multiple parasitism ; Territory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We analysed the spatial and temporal pattern of egg laying in great spotted cuckoo females using microsatellite typing to determine parentage of the eggs and nestlings found in host (magpie) nests. The results showed that there were no exclusive laying territories in the study area. Cases of multiparasitism could be due to single females laying two or more eggs in a nest, or to several females using the same nest. In the latter case multiparasitism was due to a shortage of available host nests. We argue that the need for very large laying areas and the likely small cost of sharing parental care for chicks make the costs of defending territories higher than the benefits, which has constrained the evolution of territoriality in this species.
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  • 3
    ISSN: 1432-0762
    Keywords: Brood parasitism ; Clamator glandarius ; Chick recognition ; Pica pica ; Supernormal stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hosts of brood parasites have evolved the ability to discriminate non-mimetic and even mimetic eggs, but not non-mimetic chicks. Here we demonstrate that the great spotted cuckoo Clamator glandarius does not provide its magpie Pica pica host with a super-normal stimulus that helps to avoid recognition, because single cuckoo chicks introduced into otherwise unparasitized magpie nests are not fed at a higher frequency than single magpie chicks introduced to parasitized magpie nests. Another series of experiments demonstrated that magpies have the ability to discriminate cuckoo chicks, mainly when these are introduced at the end of the nestling period, and especially when the cuckoo chick together with a magpie chick is presented to adult magpies outside the nest. This supports the idea that cuckoos exploit the obligatory reaction of magpies to feed all young that have been hatched in their nests and whose “signatures” they have learnt. Furthermore, the experimental cuckoo chicks in parasitized magpie nests were more likely to be accepted than they were in non-parasitized nests. This supports the hypothesis that magpies may learn to recognise their own nestlings as those present in the nest and may indicate that a comparison between cuckoo and magpie nestlings is the basis of discrimination.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 19 (1996), S. 538-542 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A Comparative study of different Lewis acids (metal chlorides of valences, I, II, III, IV) has been made. These catalysts are used in the synthesis of a high molecular weight ester in a stirred tank reactor using octanoic acid and n-octyl alcohol as reactants. It was found that the best efficiency of the formatted ester (n-octyl octanoate) was obtained with ferric chloride. This could be explained by the high electronegativity and the existence of free d orbitals in the Lewis acid.
    Additional Material: 7 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 20 (1997), S. 287-292 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The development and optimization of the synthesis of an analogue of sperm whale oil have been carried out. The product is an ester with characteristics similar to those of natural sperm whale oil. A central composite design was applied in the synthesis of this fine chemical. The variables selected for the present study are reaction temperature, initial concentration of catalyst and working pressure. Temperature is the most significant factor in the esterification process, and its influence is positive. Pressure influence can be neglected, and the catalyst concentration has a positive influence on the process. Depending on the temperature value, the influence of the interactions can be more important than that of the other two main effects, pressure and catalyst concentration. Response surface models have been found adequate to represent the yield of ester. The commercial quality of the synthesized product is very similar to that of natural spermaceti. Because of its low cost, this synthesis process is considered, from an economical point of view, very attractive.
    Additional Material: 3 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 19 (1996), S. 410-419 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: General simple criteria to predict and analyze the influence on trickle-bed reactors behavior of three phenomena, namely, plug flow deviations, external wetting efficiency and external mass transfer resistance, are developed. Criteria predictions are compared with results arising from a comprehensive mathematical model widely employed to describe trickle-bed reactors behavior and with other particular criteria reported in the literature. Present criteria applications to different sets of experimental data exemplify their practical utility for various actual situations and verify their validity. Besides, they constitute simple tools to diagnose detrimental on trickle-bed reactors operation.
    Additional Material: 4 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemical Engineering & Technology - CET 19 (1996), S. 315-323 
    ISSN: 0930-7516
    Keywords: Chemistry ; Industrial Chemistry and Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Intermig impellers have been postulated as very efficient for mixing highly viscous non-Newtonian fluids (such as xanthan and mycelial broths). However, no formal characterisation has been published and no fair comparisons have been made, based on accurate power drawn measurements and using equal number of impeller stages and equal diameter, if compared (for example) with the performance of Rushton turbines. Characterisation of the shape, size, and evolution of the well-mixed zones or “caverns” were correlated with power drawn, for single and dual Rushton turbines and for one- as well as two-stage Intermig unslotted impellers. Cavern evolution studies were carried out in a mixing tank (diameter=0.205 m, H/T=1.6) equipped with an accurate air bearing dynamometer. Carbopol 940 (0.25 wt.-%) was used as a model, transparent fluid. Impeller to tank diameter ratio was 0.53 for both impellers. Caverns were visualised by injecting methylene blue in the well-mixed zones. A single Rushton turbine developed larger caverns if compared with one-stage Intermig of the same diameter under power drawn below 1.5 kW m-3. At higher power drawn, both impellers behaved very similarly, reaching a limit in cavern volume of about 40% of the total liquid volume, even at very high (20 kW m03) power drawn. A similar trend characterised dual combinations: below 3 kW m-3, dual Rushtons gave larger cavern volume if compared with the performance of two-stage Intermigs. In either case, power drawn higher than 3 kW m03 was sufficient to mix more than 90% of the liquid volume. The presence or absence of the slot in the Intermig did not influence cavern development. Experiments with a smaller if compared with those obtained with the larger Intermig (D/T = 0.53).
    Additional Material: 11 Ill.
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  • 8
    ISSN: 1432-0762
    Keywords: Key words Brood parasitism ; Clamator glandarius ; Chick recognition ; Pica pica ; Supernormal stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Hosts of brood parasites have evolved the ability to discriminate nonmimetic and even mimetic eggs, but not nonmimetic chicks. Here we demonstrate that the great spotted cuckoo Clamator glandarius does not provide its magpie Pica pica host with a supernormal stimulus that helps to avoid recognition, because single cuckoo chicks introduced into otherwise unparasitized magpie nests are not fed at a higher frequency than single magpie chicks introduced to parasitized magpie nests. Another series of experiments demonstrated that magpies have the ability to discriminate cuckoo chicks, mainly when these are introduced at the end of the nestling period, and especially when the cuckoo chick together with a magpie chick is presented to adult magpies outside the nest. This supports the idea that cuckoos exploit the obligatory reaction of magpies to feed all young that have been hatched in their nests and whose “signatures” they have learnt. Furthermore, the experimental cuckoo chicks in parasitized magpie nests were more likely to be accepted than they were in nonparasitized nests. This supports the hypothesis that magpies may learn to recognise their own nestlings as those present in the nest and may indicate that a comparison between cuckoo and magpie nestlings is the basis of discrimination.
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  • 9
    ISSN: 1432-0762
    Keywords: Brood parasitism ; Clamator glandarius ; Food allocation ; Pica pica ; Supernormal stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult magpies Pica pica provide parasitic great spotted cuckoo Clamator glandarius nestlings with a diet very similar to that fed to their own chicks. In both naturally and experimentally parasitized nests, great spotted cuckoo chicks were fed at a higher rate than magpie chicks in the same nest. This preferential allocation of food by magpie parents to great spotted cuckoo chicks is consistent with the supernormal stimulus hypothesis, because this result implies that cuckoo chicks provide stronger stimuli for parental care than host chicks. Great spotted cuckoo chicks receive most of the food brought to the nest by the foster parents, because they exploit a series of stimuli which jointly (or sometimes individually) operate as a supernormal stimulus. This hypothesis predicts that if any stimulus is masked, the efficiency of the cuckoo in eliciting parental care will decrease. Here, we analyze experimentally the effects of two of these stimuli, preferential feeding of large nestlings and of nestlings with conspicuous palatal papillae. Firstly, when we experimentally introduced one medium-sized (7–9 days) cuckoo chick into an unparasitized magpie nest where the largest magpie chick was 12–15 days old, the cuckoo did not receive significantly more food than the average or the largest magpie chick. Secondly, when unparasitized nests were experimentally parasitized with a cuckoo chick that had its gape painted to mimic that of magpie chicks, the parasitic cuckoo received less food than the average magpie chick.
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  • 10
    ISSN: 1432-0762
    Keywords: Key words Brood parasitism ; Clamator glandarius ; Food allocation ; Pica pica ; Supernormal stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Adult magpies Pica pica provide parasitic great spotted cuckoo Clamator glandarius nestlings with a diet very similar to that fed to their own chicks. In both naturally and experimentally parasitized nests, great spotted cuckoo chicks were fed at a higher rate than magpie chicks in the same nest. This preferential allocation of food by magpie parents to great spotted cuckoo chicks is consistent with the supernormal stimulus hypothesis, because this result implies that cuckoo chicks provide stronger stimuli for parental care than host chicks. Great spotted cuckoo chicks receive most of the food brought to the nest by the foster parents, because they exploit a series of stimuli which jointly (or sometimes individually) operate as a supernormal stimulus. This hypothesis predicts that if any stimulus is masked, the efficiency of the cuckoo in eliciting parental care will decrease. Here, we analyze experimentally the effects of two of these stimuli, preferential feeding of large nestlings and of nestlings with conspicuous palatal papillae. Firstly, when we experimentally introduced one medium-sized (7–9 days) cuckoo chick into an unparasitized magpie nest where the largest magpie chick was 12–15 days old, the cuckoo did not receive significantly more food than the average or the largest magpie chick. Secondly, when unparasitized nests were experimentally parasitized with a cuckoo chick that had its gape painted to mimic that of magpie chicks, the parasitic cuckoo received less food than the average magpie chick.
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