| Records |
| Author |
Rosa, P.A.J.; Azevedo, A.M.; Aires-Barros, M.R. |
| Title |
Application of central composite design to the optimisation of aqueous two-phase extraction of human antibodies |
Type |
Journal Article |
| Year |
2007 |
Publication |
Journal of Chromatography. A |
Abbreviated Journal |
J Chromatogr A |
Volume  |
1141 |
Issue |
1 |
Pages |
50-60 |
| Keywords |
Analysis of Variance; Animals; Antibodies/*chemistry/*isolation & purification; Buffers; Chemical Fractionation/*methods; Horses; Humans; Hydrophobicity; Isoelectric Point; Models, Biological; Molecular Weight; Myoglobin/chemistry/isolation & purification; Osmolar Concentration; Phase Transition; Polyethylene Glycols; Serum Albumin/chemistry/isolation & purification; Sodium Chloride |
| Abstract |
The partition of human antibodies in aqueous two-phase systems (ATPSs) of polyethylene glycol (PEG) and phosphate was systematically studied using first pure proteins systems and then an artificial mixture of proteins containing 1mg/ml human immunoglobulin G (IgG), 10mg/ml serum albumin and 2mg/ml myoglobin. Preliminary results obtained using pure proteins systems indicated that the PEG molecular weight and concentration, the pH value and the salts concentration had a pronounced effect on the partitioning behaviour of all proteins. For high ionic strengths and pH values higher than the isoelectric point (pI) of the contaminant proteins, IgG could be selectively recovered on the top phase. According to these results, a face centred composite design was performed in order to optimise the purification of IgG from the mixture of proteins. The optimal conditions for the isolation of IgG were observed for high concentrations of NaCl and low concentrations of both phase forming components. The best purification was achieved using an ATPS containing 8% (w/w) PEG 3350, 10% (w/w) phosphate pH 6 and 15% (w/w) NaCl. A recovery yield of 101+/-7%, a purity of 99+/-0% and a yield of native IgG of 97+/-4% were obtained. Back extraction studies of IgG to a new phosphate phase were performed and higher yields were obtained using 10% phosphate buffer at pH 6. The total extraction yield was 76% and the purity 100%. |
| Address |
IBB Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Tecnico, Av Rovisco Pais, 1049-001 Lisbon, Portugal |
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Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0021-9673 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:17196214 |
Approved |
no |
| Call Number |
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Serial |
1842 |
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| Author |
Wolf, M.; van Doorn, G.S.; Leimar, O.; Weissing, F.J. |
| Title |
Life-history trade-offs favour the evolution of animal personalities |
Type |
Journal Article |
| Year |
2007 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
447 |
Issue |
7144 |
Pages |
581-584 |
| Keywords |
Aggression/physiology/psychology; Animals; Behavior, Animal/*physiology; *Evolution; Exploratory Behavior/physiology; Models, Biological; Personality/*physiology; Predatory Behavior/physiology; Reproduction/physiology; Risk-Taking; Selection (Genetics) |
| Abstract |
In recent years evidence has been accumulating that personalities are not only found in humans but also in a wide range of other animal species. Individuals differ consistently in their behavioural tendencies and the behaviour in one context is correlated with the behaviour in multiple other contexts. From an adaptive perspective, the evolution of animal personalities is still a mystery, because a more flexible structure of behaviour should provide a selective advantage. Accordingly, many researchers view personalities as resulting from constraints imposed by the architecture of behaviour (but see ref. 12). In contrast, we show here that animal personalities can be given an adaptive explanation. Our argument is based on the insight that the trade-off between current and future reproduction often results in polymorphic populations in which some individuals put more emphasis on future fitness returns than others. Life-history theory predicts that such differences in fitness expectations should result in systematic differences in risk-taking behaviour. Individuals with high future expectations (who have much to lose) should be more risk-averse than individuals with low expectations. This applies to all kinds of risky situations, so individuals should consistently differ in their behaviour. By means of an evolutionary model we demonstrate that this basic principle results in the evolution of animal personalities. It simultaneously explains the coexistence of behavioural types, the consistency of behaviour through time and the structure of behavioural correlations across contexts. Moreover, it explains the common finding that explorative behaviour and risk-related traits like boldness and aggressiveness are common characteristics of animal personalities. |
| Address |
Theoretical Biology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, Kerklaan 30, 9751 NN Haren, The Netherlands |
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Thesis |
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Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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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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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:17538618 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4098 |
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| Author |
Bell, A.M. |
| Title |
Evolutionary biology: animal personalities |
Type |
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| Year |
2007 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
447 |
Issue |
7144 |
Pages |
539-540 |
| Keywords |
Aggression/physiology/psychology; Animals; Behavior, Animal/*physiology; *Evolution; Humans; *Models, Biological; Personality/genetics/*physiology; Reproduction/genetics/physiology; Risk-Taking; Selection (Genetics) |
| Abstract |
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English |
Summary Language |
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Series Title |
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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:17538607 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
4099 |
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| Author |
Grosenick, L.; Clement, T.S.; Fernald, R.D. |
| Title |
Fish can infer social rank by observation alone |
Type |
Journal Article |
| Year |
2007 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
445 |
Issue |
7126 |
Pages |
429-432 |
| Keywords |
Aggression/physiology; Animals; Cognition/*physiology; Female; Fishes/*physiology; Learning/*physiology; Male; Models, Biological; *Social Dominance; Territoriality |
| Abstract |
Transitive inference (TI) involves using known relationships to deduce unknown ones (for example, using A > B and B > C to infer A > C), and is thus essential to logical reasoning. First described as a developmental milestone in children, TI has since been reported in nonhuman primates, rats and birds. Still, how animals acquire and represent transitive relationships and why such abilities might have evolved remain open problems. Here we show that male fish (Astatotilapia burtoni) can successfully make inferences on a hierarchy implied by pairwise fights between rival males. These fish learned the implied hierarchy vicariously (as 'bystanders'), by watching fights between rivals arranged around them in separate tank units. Our findings show that fish use TI when trained on socially relevant stimuli, and that they can make such inferences by using indirect information alone. Further, these bystanders seem to have both spatial and featural representations related to rival abilities, which they can use to make correct inferences depending on what kind of information is available to them. Beyond extending TI to fish and experimentally demonstrating indirect TI learning in animals, these results indicate that a universal mechanism underlying TI is unlikely. Rather, animals probably use multiple domain-specific representations adapted to different social and ecological pressures that they encounter during the course of their natural lives. |
| Address |
Department of Biological Sciences, Stanford University, Stanford, California, 94305, USA. logang@stanford.edu |
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Place of Publication |
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English |
Summary Language |
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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:17251980 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
600 |
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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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Original Title |
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Series Title |
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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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| Area |
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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 |
Rands, S.A.; Cowlishaw, G.; Pettifor, R.A.; Rowcliffe, J.M.; Johnstone, R.A. |
| Title |
Spontaneous emergence of leaders and followers in foraging pairs |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
423 |
Issue |
6938 |
Pages |
432-434 |
| Keywords |
Animals; *Energy Metabolism; Food; *Food Chain; *Models, Biological; Motor Activity; *Social Behavior; Time Factors |
| Abstract |
Animals that forage socially often stand to gain from coordination of their behaviour. Yet it is not known how group members reach a consensus on the timing of foraging bouts. Here we demonstrate a simple process by which this may occur. We develop a state-dependent, dynamic game model of foraging by a pair of animals, in which each individual chooses between resting or foraging during a series of consecutive periods, so as to maximize its own individual chances of survival. We find that, if there is an advantage to foraging together, the equilibrium behaviour of both individuals becomes highly synchronized. As a result of this synchronization, differences in the energetic reserves of the two players spontaneously develop, leading them to adopt different behavioural roles. The individual with lower reserves emerges as the 'pace-maker' who determines when the pair should forage, providing a straightforward resolution to the problem of group coordination. Moreover, the strategy that gives rise to this behaviour can be implemented by a simple 'rule of thumb' that requires no detailed knowledge of the state of other individuals. |
| Address |
Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK. s.rands@zoo.cam.ac.uk |
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Thesis |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
PMID:12761547 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5138 |
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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 |
| Abstract |
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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 |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12606989 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
467 |
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| Author |
Conradt, L.; Roper, T.J. |
| Title |
Group decision-making in animals |
Type |
Journal Article |
| Year |
2003 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
421 |
Issue |
6919 |
Pages |
155-158 |
| Keywords |
Animals; Behavior, Animal/*physiology; *Decision Making; Democracy; Group Processes; *Models, Biological; Population Density; Social Behavior |
| Abstract |
Groups of animals often need to make communal decisions, for example about which activities to perform, when to perform them and which direction to travel in; however, little is known about how they do so. Here, we model the fitness consequences of two possible decision-making mechanisms: 'despotism' and 'democracy'. We show that under most conditions, the costs to subordinate group members, and to the group as a whole, are considerably higher for despotic than for democratic decisions. Even when the despot is the most experienced group member, it only pays other members to accept its decision when group size is small and the difference in information is large. Democratic decisions are more beneficial primarily because they tend to produce less extreme decisions, rather than because each individual has an influence on the decision per se. Our model suggests that democracy should be widespread and makes quantitative, testable predictions about group decision-making in non-humans. |
| Address |
School of Biological Sciences, University of Sussex, Brighton BN1 9QG, UK. l.conradt@sussex.ac.uk |
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Place of Publication |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:12520299 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
5136 |
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| Author |
Wilson, A.M.; McGuigan, M.P.; Su, A.; van Den Bogert, A.J. |
| Title |
Horses damp the spring in their step |
Type |
Journal Article |
| Year |
2001 |
Publication |
Nature |
Abbreviated Journal |
Nature |
| Volume |
414 |
Issue |
6866 |
Pages |
895-899 |
| Keywords |
Animals; Biomechanics; Elasticity; Forelimb; Gait; Horses/anatomy & histology/*physiology; Leg Bones/*physiology; Locomotion; Models, Biological; Muscle Fibers/physiology; Muscle, Skeletal/anatomy & histology/*physiology; Tendons/anatomy & histology/*physiology; Vibration |
| Abstract |
The muscular work of galloping in horses is halved by storing and returning elastic strain energy in spring-like muscle-tendon units.These make the legs act like a child's pogo stick that is tuned to stretch and recoil at 2.5 strides per second. This mechanism is optimized by unique musculoskeletal adaptations: the digital flexor muscles have extremely short fibres and significant passive properties, whereas the tendons are very long and span several joints. Length change occurs by a stretching of the spring-like digital flexor tendons rather than through energetically expensive length changes in the muscle. Despite being apparently redundant for such a mechanism, the muscle fibres in the digital flexors are well developed. Here we show that the mechanical arrangement of the elastic leg permits it to vibrate at a higher frequency of 30-40 Hz that could cause fatigue damage to tendon and bone. Furthermore, we show that the digital flexor muscles have minimal ability to contribute to or regulate significantly the 2.5-Hz cycle of movement, but are ideally arranged to damp these high-frequency oscillations in the limb. |
| Address |
Department of Veterinary Basic Sciences, The Royal Veterinary College, Hatfield, Herts AL9 7TA, UK. awilson@rvc.ac.uk |
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Place of Publication |
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English |
Summary Language |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0028-0836 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:11780059 |
Approved |
no |
| Call Number |
Equine Behaviour @ team @ |
Serial |
2300 |
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| Author |
Zhou, W.-X.; Sornette, D.; Hill, R.A.; Dunbar, R.I.M. |
| Title |
Discrete hierarchical organization of social group sizes |
Type |
Journal Article |
| Year |
2005 |
Publication |
Proceedings. Biological sciences / The Royal Society |
Abbreviated Journal |
Proc Biol Sci |
| Volume |
272 |
Issue |
1561 |
Pages |
439-444 |
| Keywords |
Anthropology, Cultural; *Group Structure; Humans; *Models, Biological; *Social Behavior; *Social Environment |
| Abstract |
The 'social brain hypothesis' for the evolution of large brains in primates has led to evidence for the coevolution of neocortical size and social group sizes, suggesting that there is a cognitive constraint on group size that depends, in some way, on the volume of neural material available for processing and synthesizing information on social relationships. More recently, work on both human and non-human primates has suggested that social groups are often hierarchically structured. We combine data on human grouping patterns in a comprehensive and systematic study. Using fractal analysis, we identify, with high statistical confidence, a discrete hierarchy of group sizes with a preferred scaling ratio close to three: rather than a single or a continuous spectrum of group sizes, humans spontaneously form groups of preferred sizes organized in a geometrical series approximating 3-5, 9-15, 30-45, etc. Such discrete scale invariance could be related to that identified in signatures of herding behaviour in financial markets and might reflect a hierarchical processing of social nearness by human brains. |
| Address |
State Key Laboratory of Chemical Reaction Engineering, East China University of Science and Technology, Shanghai 200237, China |
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English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0962-8452 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:15734699 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
549 |
| Permanent link to this record |
