| Records |
| Author |
Gonzalez-Fernandez, J.M.; Atta, S.E. |
| Title |
Facilitated transport of oxygen in the presence of membranes in the diffusion path |
Type |
Journal Article |
| Year |
1982 |
Publication |
Biophysical Journal |
Abbreviated Journal |
Biophys J |
| Volume |
38 |
Issue |
2 |
Pages |
133-141 |
| Keywords |
Animals; Biological Transport, Active; Cell Membrane/*metabolism; Diffusion; Dogs; Horses; Humans; Kinetics; Mathematics; *Models, Biological; Muscles/*metabolism; Oxygen/*metabolism |
| Abstract |
Most of the experimental observations on facilitated transport have been done with millipore filters, and all the theoretical studies have assumed homogeneous spatial properties. In striated muscle there exist membranes that may impede the diffusion of the carrier myoglobin. In this paper a theoretical study is undertaken to analyze the transport in the presence of membranes in the diffusion path. For the numerical computations physiologically relevant values of the parameters were chosen. The numerical results indicate that the presence of membranes tends to decrease the facilitation. For the nonlinear chemical kinetics of the reaction of oxygen with the carrier, this decrement also depends on the location of the membranes. At the higher oxygen concentration side of each membrane the flow of combined oxygen is transferred to the flow of dissolved oxygen. The reverse process occurs at the lower concentration side. Jump discontinuities of the concentration of the oxygen-carrier compound at each membrane are associated with these transfers. The decrement of facilitation is due to the cumulative effect of these jump discontinuities. |
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English |
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| ISSN |
0006-3495 |
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| Notes |
PMID:7093418 |
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no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
3806 |
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| Author |
Santamaria, S.; Bobbert, M.F.; Back, W.; Barneveld, A.; van Weeren, P.R. |
| Title |
Effect of early training on the jumping technique of horses |
Type |
Journal Article |
| Year |
2005 |
Publication |
American Journal of Veterinary Research |
Abbreviated Journal |
Am J Vet Res |
| Volume |
66 |
Issue |
3 |
Pages |
418-424 |
| Keywords |
Age Factors; Analysis of Variance; Animals; Biomechanics; Forelimb/physiology; Gait/*physiology; Hindlimb/physiology; Horses/growth & development/*physiology; Locomotion/*physiology; Models, Biological; Physical Conditioning, Animal/*methods |
| Abstract |
OBJECTIVE: To investigate the effects of early training for jumping by comparing the jumping technique of horses that had received early training with that of horses raised conventionally. ANIMALS: 40 Dutch Warmblood horses. PROCEDURE: The horses were analyzed kinematically during free jumping at 6 months of age. Subsequently, they were allocated into a control group that was raised conventionally and an experimental group that received 30 months of early training starting at 6 months of age. At 4 years of age, after a period of rest in pasture and a short period of training with a rider, both groups were analyzed kinematically during free jumping. Subsequently, both groups started a 1-year intensive training for jumping, and at 5 years of age, they were again analyzed kinematically during free jumping. In addition, the horses competed in a puissance competition to test maximal performance. RESULTS: Whereas there were no differences in jumping technique between experimental and control horses at 6 months of age, at 4 years, the experimental horses jumped in a more effective manner than the control horses; they raised their center of gravity less yet cleared more fences successfully than the control horses. However, at 5 years of age, these differences were not detected. Furthermore, the experimental horses did not perform better than the control horses in the puissance competition. CONCLUSIONS AND CLINICAL RELEVANCE: Specific training for jumping of horses at an early age is unnecessary because the effects on jumping technique and jumping capacity are not permanent. |
| Address |
Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, NL-3584 CM Utrecht, The Netherlands |
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English |
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0002-9645 |
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| Notes |
PMID:15822585 |
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no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4037 |
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| Author |
McClearn, G.E. |
| Title |
Behavioral genetics |
Type |
Journal Article |
| Year |
1971 |
Publication |
Behavioral Science |
Abbreviated Journal |
Behav Sci |
| Volume |
16 |
Issue |
1 |
Pages |
64-81 |
| Keywords |
Amino Acid Metabolism, Inborn Errors; Animals; Aptitude; Behavior, Animal; Chromosome Aberrations; Cognition; Cytogenetics; Female; *Genetics, Behavioral; Genetics, Population; Humans; Intelligence; Mental Retardation; Mice; Models, Biological; Personality; Phenylketonurias; Pregnancy; Research; Schizophrenia; Sex Chromosome Aberrations; Twins |
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English |
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Edition |
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| ISSN |
0005-7940 |
ISBN |
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Conference |
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| Notes |
PMID:5105941 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4150 |
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| Author |
Reimers, M.; Schwarzenberger, F.; Preuschoft, S. |
| Title |
Rehabilitation of research chimpanzees: stress and coping after long-term isolation |
Type |
Journal Article |
| Year |
2007 |
Publication |
Hormones and Behavior |
Abbreviated Journal |
Horm Behav |
| Volume |
51 |
Issue |
3 |
Pages |
428-435 |
| Keywords |
Adaptation, Psychological/*physiology; Animals; *Animals, Laboratory; Exploratory Behavior; Hydrocortisone/analysis/metabolism; Male; Models, Biological; *Pan troglodytes; Social Dominance; Social Environment; *Social Isolation/psychology; Stress/*rehabilitation/veterinary; Time |
| Abstract |
We report on the permanent retirement of chimpanzees from biomedical research and on resocialization after long-term social isolation. Our aim was to investigate to what extent behavioral and endocrine measures of stress in deprived laboratory chimpanzees can be improved by a more species-typical social life style. Personality in terms of novelty responses, social dominance after resocialization and hormonal stress susceptibility were affected by the onset of maternal separation of infant chimpanzees and duration of deprivation. Chimpanzees, who were separated from their mothers at a younger age and kept in isolation for more years appeared to be more timid personalities, less socially active, less dominant and more susceptible to stress, as compared to chimpanzees with a less severe deprivation history. However, permanent retirement from biomedical research in combination with therapeutic resocialization maximizing chimpanzees' situation control resulted in reduced fecal cortisol metabolite levels. Our results indicate that chimpanzees can recover from severe social deprivation, and may experience resocialization as less stressful than solitary housing. |
| Address |
Department of Natural Sciences, Institute of Biochemistry, University of Veterinary Medicine, Veterinarplatz 1, 1210 Vienna, Austria. reimers@wild-vet.at |
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English |
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0018-506X |
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Conference |
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| Notes |
PMID:17292368 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4188 |
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| Author |
Flack, J.C.; de Waal, F.B.M.; Krakauer, D.C. |
| Title |
Social structure, robustness, and policing cost in a cognitively sophisticated species |
Type |
Journal Article |
| Year |
2005 |
Publication |
The American Naturalist |
Abbreviated Journal |
Am Nat |
| Volume |
165 |
Issue |
5 |
Pages |
E126-139 |
| Keywords |
Animals; *Behavior, Animal; Cognition; Conflict (Psychology); Female; Macaca nemestrina/*physiology; Male; Models, Biological; *Social Behavior |
| Abstract |
Conflict management is one of the primary requirements for social complexity. Of the many forms of conflict management, one of the rarest and most interesting is third-party policing, or intervening impartially to control conflict. Third-party policing should be hard to evolve because policers personally pay a cost for intervening, while the benefits are diffused over the whole group. In this study we investigate the incidence and costs of policing in a primate society. We report quantitative evidence of non-kin policing in the nonhuman primate, the pigtailed macaque. We find that policing is effective at reducing the intensity of or terminating conflict when performed by the most powerful individuals. We define a measure, social power consensus, that predicts effective low-cost interventions by powerful individuals and ineffective, relatively costly interventions by low-power individuals. Finally, we develop a simple probabilistic model to explore whether the degree to which policing can effectively reduce the societal cost of conflict is dependent on variance in the distribution of power. Our data and simple model suggest that third-party policing effectiveness and cost are dependent on power structure and might emerge only in societies with high variance in power. |
| Address |
Santa Fe Institute, Santa Fe, New Mexico 87501, USA. jflack@santafe.edu |
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English |
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Series Issue |
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Edition |
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| ISSN |
1537-5323 |
ISBN |
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| Notes |
PMID:15795848 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
168 |
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| Author |
Flack, J.C.; Girvan, M.; de Waal, F.B.M.; Krakauer, D.C. |
| Title |
Policing stabilizes construction of social niches in primates |
Type |
Journal Article |
| Year |
2006 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
439 |
Issue |
7075 |
Pages |
426-429 |
| Keywords |
Animals; Conflict (Psychology); Female; Macaca nemestrina/*physiology/*psychology; Male; Models, Biological; *Social Behavior |
| Abstract |
All organisms interact with their environment, and in doing so shape it, modifying resource availability. Termed niche construction, this process has been studied primarily at the ecological level with an emphasis on the consequences of construction across generations. We focus on the behavioural process of construction within a single generation, identifying the role a robustness mechanism--conflict management--has in promoting interactions that build social resource networks or social niches. Using 'knockout' experiments on a large, captive group of pigtailed macaques (Macaca nemestrina), we show that a policing function, performed infrequently by a small subset of individuals, significantly contributes to maintaining stable resource networks in the face of chronic perturbations that arise through conflict. When policing is absent, social niches destabilize, with group members building smaller, less diverse, and less integrated grooming, play, proximity and contact-sitting networks. Instability is quantified in terms of reduced mean degree, increased clustering, reduced reach, and increased assortativity. Policing not only controls conflict, we find it significantly influences the structure of networks that constitute essential social resources in gregarious primate societies. The structure of such networks plays a critical role in infant survivorship, emergence and spread of cooperative behaviour, social learning and cultural traditions. |
| Address |
Santa Fe Institute, Santa Fe, New Mexico 87501, USA. jflack@santafe.edu |
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English |
Summary Language |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1476-4687 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:16437106 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
298 |
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| Author |
Cameron, E.Z. |
| Title |
Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism |
Type |
Journal Article |
| Year |
2004 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
| Volume |
271 |
Issue |
1549 |
Pages |
1723-1728 |
| Keywords |
Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors |
| Abstract |
Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios. |
| Address |
Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za |
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English |
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Edition |
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0962-8452 |
ISBN |
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| Notes |
PMID:15306293 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
413 |
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| Author |
Johnson, D.D.P.; Stopka, P.; Knights, S. |
| Title |
Sociology: The puzzle of human cooperation |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
421 |
Issue |
6926 |
Pages |
911-2; discussion 912 |
| Keywords |
Altruism; *Cooperative Behavior; Evolution; Humans; *Models, Biological; Punishment; Reward; Risk |
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| Address |
Olin Institute for Strategic Studies, Harvard University, Cambridge, Massachusetts 02138, USA. dominic@post.harvard.edu |
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English |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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| Notes |
PMID:12606989 |
Approved |
no |
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refbase @ user @ |
Serial |
467 |
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| Author |
Scheffer, M.; van Nes, E.H. |
| Title |
Self-organized similarity, the evolutionary emergence of groups of similar species |
Type |
Journal Article |
| Year |
2006 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
| Volume |
103 |
Issue |
16 |
Pages |
6230-6235 |
| Keywords |
Animals; *Competitive Behavior; *Ecosystem; *Evolution; *Models, Biological |
| Abstract |
Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes. |
| Address |
Aquatic Ecology and Water Quality Management Group, Department of Environmental Sciences, Wageningen University, P.O. Box 8080, 6700 DD, Wageningen, The Netherlands. marten.scheffer@wur.nl |
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English |
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Edition |
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0027-8424 |
ISBN |
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Conference |
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| Notes |
PMID:16585519 |
Approved |
no |
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refbase @ user @ |
Serial |
510 |
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| Author |
Mettke-Hofmann, C.; Gwinner, E. |
| Title |
Long-term memory for a life on the move |
Type |
Journal Article |
| Year |
2003 |
Publication |
Proceedings of the National Academy of Sciences of the United States of America |
Abbreviated Journal |
Proc. Natl. Acad. Sci. U.S.A. |
| Volume |
100 |
Issue |
10 |
Pages |
5863-5866 |
| Keywords |
Animals; Germany; Israel; Memory/*physiology; Models, Biological; Periodicity; Songbirds/*physiology |
| Abstract |
Evidence is accumulating that cognitive abilities are shaped by the specific ecological conditions to which animals are exposed. Long-distance migratory birds may provide a striking example of this. Field observations have shown that, at least in some species, a substantial proportion of individuals return to the same breeding, wintering, and stopover sites in successive years. This observation suggests that migrants have evolved special cognitive abilities that enable them to accomplish these feats. Here we show that memory of a particular feeding site persisted for at least 12 months in a long-distance migrant, whereas a closely related nonmigrant could remember such a site for only 2 weeks. Thus, it seems that the migratory lifestyle has influenced the learning and memorizing capacities of migratory birds. These results build a bridge between field observations suggesting special memorization feats of migratory birds and previous neuroanatomical results from the same two species indicating an increase in relative hippocampal size from the first to the second year of life in the migrant but not in the nonmigrant. |
| Address |
Max Planck Research Centre for Ornithology, Department of Biological Rhythms and Behaviour, Von-der-Tann-Strasse 7, 82346 Andechs, Germany. mettke-hofmann@erl.ornithol.mpg.de |
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English |
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Series Title |
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Series Issue |
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Edition |
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0027-8424 |
ISBN |
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| Notes |
PMID:12719527 |
Approved |
no |
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refbase @ user @ |
Serial |
511 |
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