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  • 1
    Electronic Resource
    Electronic Resource
    Temperature dependence of the rate constants for the addition of hydroxyl to benzene and to some monosubstituted aromatics (aniline, bromobenzene, and nitrobenzene) and the unimolecular decay of the adducts. Part 2. Kinetics into a quasi-equilibrium (1986)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 90 (1986), S. 3251-3259 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100405a040
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  • 2
    Electronic Resource
    Electronic Resource
    Feeding performance of Lake Victoria rock cichlids: testing predictions from morphology (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 53 (1998), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Cichlid fishes that seem specialized phenotypically to exploit certain resources often act as generalists in the field. It is attempted to resolve this paradox by measuring feeding performance. There are two ways of feeding, namely suction feeding and biting, that set conflicitng demands on the anatomy. Rock-dwelling cichlids of the genus Neochromis are specialized biters, feeding largely on filamentous algae and benthic organisms. Pundamilia nyererei is one of the most specialized suction feeders among rock cichlids, its diet being zooplankton and insect larvae. A morphological analysis showed that the three Neochromis species are better adapted anatomically to biting than P. nyererei, while P. nyererei is better adapted to suction feeding. Feeding performance was tested on algal substitute and Chaoborus larvae, representing filamentous algae and zooplankton, respectively. As expected the Neochromis species fed most efficiently on algal substitute, N. rufocaudalis and N. omnicaeruleus taking per bite 2.6 times as much as P. nyererei, and N. greenwoodi 1.7 times. Unexpectedly, the species examined were all well able to collect Chaoborus. P. nyererei collected only 1.2 times as many larvae per suction act as the Neochromis species. Analysis of the stomach contents showed that P. nyererei punctured, or lacerated, the larvae with the pharyngeal jaws, while the Neochromis species swallowed them mostly intact. Thus, feeding on Chaoborus, P. nyererei may be optimizing energy gain and not intake rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1998.tb01022.x
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  • 3
    Electronic Resource
    Electronic Resource
    The tilapiine fish stock of Lake Victoria before and after the Nile perch upsurge (2002)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 60 (2002), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Since the beginning of fisheries in Lake Victoria, two native tilapiine species, Oreochromis esculentus and Oreochromis variabilis, were the main target of the local fishermen. A continuous increase in fishing pressure led initially to a declining catch per unit of effort, and a smaller average fish size; eventually, there was a reduced landing of tilapiines. To boost the fisheries, three alien tilapiine species and the Nile perch Lates niloticus were introduced. Thirty years after its introduction, Oreochromis niloticus appeared to be the most successful tilapiine species. It replaced the indigenous tilapiines almost completely before the Nile perch came to dominate the ecosystem of Lake Victoria. Reduced fishing pressure on the tilapiines in the 1980s, due to the shift of the local fishery towards the Nile perch, resulted in an increase in the stock of O. niloticus and an increase in average fish size. Subsequently, the total mass of O. niloticus landed increased. The stocks of the indigenous tilapiines did not recover but declined to extremely low levels, or vanished from the main lake. Currently, these species still occur in satellite lakes of Lake Victoria, from which O. niloticus is absent. Nile perch feed on O. niloticus; however, the limited overlap in distribution between piscivorous Nile perch and O. niloticus of consumable sizes is probably an important factor in explaining the coexistence of the two species. The main cause of the disappearance of the native tilapiine species is presumed to be competitive dominance by O. niloticus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.2002.tb02413.x
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  • 4
    Electronic Resource
    Electronic Resource
    Direct mate choice maintains diversity among sympatric cichlids in Lake Victoria (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 53 (1998), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mate choice may play an important role in animal speciation. The haplochromine cichlids of Lake Victoria are suitable to test this hypothesis. Diversity in ecology, coloration and anatomy evolved in these fish faster than postzygotic barriers to gene flow, and little is known about how this diversity is maintained. It was tested whether recognizable forms are selection-maintained morphs or reproductively isolated species by investigating in the field reproductive timing, location of spawning sites, and mate choice behaviour. There was a large interspecific overlap in timing of breeding and location of spawning sites, which was largest in members of the same genus. Behavioural mate choice of such closely related taxa was highly assortative, such that it is likely that they are sexually isolated species and that direct mate choice is the major force that directs gene flow and maintains form diversity. The results differ from what is known about recent radiations of other lacustrine fish groups where speciation seems to be driven by diverging microhabitat preferences or diverging timing of reproduction, but are in agreement with predictions from models of speciation by diverging mate preferences.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1998.tb01016.x
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  • 5
    Electronic Resource
    Electronic Resource
    Lost zooplanktivorous cichlid from Lake Victoria reappears with a new trade (2003)
    Oxford, UK : Blackwell Science, Ltd
    Ecology of freshwater fish 12 (2003), S. 0 
    Details
    ISSN: 1600-0633
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract –  The zooplanktivorous cichlid Haplochromis pyrrhocephalus, which was one of the most common haplochromine species in the Mwanza Gulf of Lake Victoria, had almost completely disappeared after the Nile perch upsurge in the 1980s. In the second half of the 1990s, this species suddenly reappeared in the strongly changed ecosystem. Gut content investigation revealed a change in diet. Currently, H. pyrrhocephalus eats large prey more frequently than in the past. These large prey comprise fish, shrimps and molluscs. The latter two were never encountered in specimens from the past. Particularly feeding on molluscs was unexpected, as it had been suggested that, because of anatomical constraints, molluscivory and zooplanktivory are incompatible in cichlid fish. Our observations provide a new example of the extreme versatility in feeding behaviour in haplochromine cichlids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1600-0633.2003.00023.x
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  • 6
    Electronic Resource
    Electronic Resource
    Aggregation behavior of hydrophobically modified β-cyclodextrins in aqueous solution (1996)
    Springer
    Journal of inclusion phenomena and macrocyclic chemistry 25 (1996), S. 25-28 
    Details
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Three amphiphilic β-cyclodextrins in aqueous solution were investigated upon their aggregation behavior. Surface methods, conductivity and scattering methods were used to determine the cmc and radius of gyration of the aggregates. Depending on the cotenside it was possible to shift the cmc to lower concentrations. Above the cmc small spherelike aggregates existed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01041529
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  • 7
    Electronic Resource
    Electronic Resource
    Destruction of fisheries in Africa's lakes (1985)
    [s.l.] : Nature Publishing Group
    Nature 315 (1985), S. 19-20 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] LAKE Victoria in East Africa, with an area of some 68,635 km2, has a naturally rich and diverse fish fauna and formerly supported important fisheries, based largely on herbivores and detritus feeders of the family Cichlidae1·3. Fisheries based on such short food chains are ecologically the most ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/315019a0
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  • 8
    Electronic Resource
    Electronic Resource
    Über Gefäßveränderungen bei Paralytikern (1925)
    Springer
    European archives of psychiatry and clinical neuroscience 74 (1925), S. 326-336 
    Details
    ISSN: 1433-8491
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01814190
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  • 9
    Electronic Resource
    Electronic Resource
    Über anatomische Befunde am Verdauungsapparat von Schizophrenen (1929)
    Springer
    European archives of psychiatry and clinical neuroscience 88 (1929), S. 624-630 
    Details
    ISSN: 1433-8491
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01814160
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  • 10
    Electronic Resource
    Electronic Resource
    Micelle-polymer complexes as studied by the ESR spin probe technique (1987)
    Springer
    Colloid & polymer science 265 (1987), S. 42-44 
    Details
    ISSN: 1435-1536
    Keywords: Micelle-polymer complexes ; electron spin resonance ; rotational correlation times ; headgroup packing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Complexes between sodium dodecyl sulfate micelles and the water-soluble polymers poly(N-vinylpyrrolidone), poly(ethylene oxide) and a copolymer of poly (vinyl alcohol) and poly(vinyl acetate) have been studied in aqueous solution by the electron spin resonance (ESR) technique using di-tert-butyl nitroxide as a spin probe. The effective rotational correlation times reveal lowering of the critical micelle concentration and decreased headgroup packing in the micelle upon interaction with the polymers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01422662
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