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Author Kronfeld, D.S.; Custalow, S.E.; Ferrante, P.L.; Taylor, L.E.; Wilson, J.A.; Tiegs, W. url  doi
openurl 
  Title Acid-base responses of fat-adapted horses: relevance to hard work in the heat Type Journal Article
  Year 1998 Publication Applied Animal Behaviour Science Abbreviated Journal Appl. Anim. Behav. Sci.  
  Volume 59 Issue 1-3 Pages 61-72  
  Keywords Acid-base; Strong ion difference; pCO2; Exercise; Fat adaptation; Corn oil; Ambient heat; Horse  
  Abstract Feeding and training may affect acid-base responses to strenuous exercise. Acidosis usually correlates with higher blood lactate concentrations during intense exercise, but alkalosis has been found in several studies of horses, and higher lactate responses during sprints have been found in fat adapted horses. To elucidate these unexpected findings, we applied a comprehensive physicochemical approach to evaluate acid-base responses during exercise in fat adapted horses. In incremental tests and repeated sprints, changes in blood [H+] were dependent upon corresponding changes in pCO2 but not strong ion difference (SID, the algebraic sum of ions of sodium, potassium, chloride and lactate). The influence of changes in [Lac-] were largely offset by changes in [Na+], [K+] and [Cl-], so that SID was unchanged and did not contribute to the exercise induced acidemia, so it may be inaccurate to term this a lacticacidosis. During repeated sprints, central venous [H+] increased (acidosis) but arterial [H+] decreased (alkalosis). These changes were consistent with concurrent changes in venous and arterial pCO2 but not SID. Fat adaptation decreased mixed venous pCO2 during repeated sprints, which is consistent with the lower respiratory quotient associated with fat oxidation. Less pulmonary work to eliminate CO2 could benefit horses under hot and humid conditions, especially those with mildly reduced pulmonary function. The blood lactate response was decreased during aerobic tests but increased during anaerobic tests on fat adapted horses. Fat adaptation appears to facilitate the metabolic regulation of glycolysis, by sparing glucose and glycogen at work of low intensity, but by promoting glycolysis when power is needed for high intensity exercise. The blood lactate response to repeated sprints was increased more by the combination of fat adaptation and oral supplementation of sodium bicarbonate than by the sum of the responses to fat alone or bicarbonate alone. This synergism suggests that need for further studies of the interaction of fat adaptation with dietary cation-anion balance, especially under hot conditions. These results integrate harmoniously with previous findings of lower feed intake and fecal output, lower loads of heat and CO2, lower water losses in the feces and by evaporation, and less spontaneous activity and reactivity in fat adapted horses. Thus fat adaptation confers several advantages on horses and presumably other equids used for hard work, especially in the heat.  
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  ISSN 0168-1591 ISBN Medium  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 4832  
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Author Watts, D.J.; Strogatz, S.H. url  doi
openurl 
  Title Collective dynamics of /`small-world/' networks Type Journal Article
  Year 1998 Publication Abbreviated Journal Nature  
  Volume 393 Issue 6684 Pages 440-442  
  Keywords  
  Abstract Networks of coupled dynamical systems have been used to model biological oscillators Josephson junction arrays excitable media, neural networks spatial games11, genetic control networks12 and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes. Here we explore simple models of networks that can be tuned through this middle ground: regular networks 'rewired' to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them 'small-world' networks, by analogy with the small-world phenomenon (popularly known as six degrees of separation). The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices.  
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  Series Volume Series Issue Edition  
  ISSN 0028-0836 ISBN Medium  
  Area Expedition Conference  
  Notes 10.1038/30918 Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 4989  
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Author Gosling, S.D. url  doi
openurl 
  Title Personality dimensions in spotted hyenas (Crocuta crocuta) Type Journal Article
  Year 1998 Publication Journal of Comparative Psychology (Washington, D.C. : 1983) Abbreviated Journal J Comp Psychol  
  Volume 112 Issue 2 Pages 107-118  
  Keywords Animals; Carnivora/*psychology; Female; Humans; Male; *Personality; Personality Assessment/statistics & numerical data; Psychometrics; Reproducibility of Results; Species Specificity; Temperament  
  Abstract Personality ratings of 34 spotted hyenas (Crocuta crocuta) were made by 4 observers who knew the animals well. Analyses suggest that (a) hyena personality traits were rated with generally high reliability; (b) 5 broad dimensions (Assertiveness, Excitability, Human-Directed Agreeableness, Sociability, and Curiosity) captured about 75% of the total variance; (c) this dimensional structure could not be explained in terms of dominance status, sex, age, or appearance; and (d) as expected, female hyenas were more assertive than male hyenas. Comparisons with previous research provide evidence for the cross-species generality of Excitability, Sociability, and especially Assertiveness. Discussion focuses on methodological issues in research on animal personality and on the potential contributions this research can make for understanding the biological and environmental bases of personality.  
  Address Department of Psychology, University of California, Berkeley 94720-1650, USA. samiam@uclink.berkeley.edu  
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  Series Volume Series Issue Edition  
  ISSN 0735-7036 ISBN Medium  
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  Notes PMID:9642781 Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5019  
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Author Oakenfull, E.A.; Ryder, O.A. doi  openurl
  Title Mitochondrial control region and 12S rRNA variation in Przewalski's horse (Equus przewalskii) Type Journal Article
  Year 1998 Publication Animal Genetics Abbreviated Journal Anim Genet  
  Volume 29 Issue 6 Pages 456-459  
  Keywords Animals; DNA, Mitochondrial/*genetics; Female; *Genetic Variation; Horses/*genetics; Male; Pedigree; RNA, Ribosomal/*genetics  
  Abstract Variation in the control region and the 12S rRNA gene of all surviving mitochondrial lineages of Przewalski's horse was investigated. Variation is low despite the present day population being descended from 13 individuals probably representing animals from three different regions of its range. Phylogenetic comparison of these sequences, with sequences for the domestic horse, does not resolve the ancestral status of either horse.  
  Address Center for Reproduction of Endangered Species, Zoological Society of San Diego, CA 92112, USA  
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  Series Volume Series Issue Edition  
  ISSN 0268-9146 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:9883508 Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5040  
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Author Matsumura, S.; Kobayashi, T. url  doi
openurl 
  Title A game model for dominance relations among group-living animals Type Journal Article
  Year 1998 Publication Behavioral Ecology and Sociobiology Abbreviated Journal Behav. Ecol. Sociobiol.  
  Volume 42 Issue 2 Pages 77-84  
  Keywords Dominance – Hawk-dove games – Resource-holding potential – Asymmetry – Evolutionarily stable strategy  
  Abstract Abstract   We present here an attempt to understand behaviors of dominant individuals and of subordinate individuals as behavior strategies in an asymmetric “hawk-dove” game. We assume that contestants have perfect information about relative fighting ability and the value of the resource. Any type of asymmetry, both relevant to and irrelevant to the fighting ability, can be considered. It is concluded that evolutionarily stable strategies (ESSs) depend on the resource value (V), the cost of injury (D), and the probability that the individual in one role will win (x). Different ESSs can exist even when values of V, D, and x are the same. The characteristics of dominance relations detected by observers may result from the ESSs that the individuals are adopting. The model explains some characteristics of dominance relations, for example, the consistent outcome of contests, the rare occurrence of escalated fights, and the discrepancy between resource holding potential (RHP) and dominance relations, from the viewpoint of individual selection.  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5102  
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Author Keil, N.M., Sambraus, H.H. url  openurl
  Title “Intervenors” in agonistic interactions amongst domesticated goats Type Journal Article
  Year 1998 Publication Zeitschrift fur Säugetierkunde Abbreviated Journal Z. Säugetierk.  
  Volume 63 Issue 5 Pages 266-272  
  Keywords Behaviour; Domestication; Goat; Intervention; Rank order  
  Abstract Social behaviour was observed in individually marked goats in two herds. The goats from one herd (n = 98) were horned, those of the other herd (n = 83) were polled. By recording agonistic interactions within the herds, a dominance index was determined for each animal. In both herds, intervention took place. Intervention is defined as one animal pushing in between two fighters, and thus ending the fight. More cases of intervention took place per individual animal amongst the horned goats than amongst the polled ones. Goats which intervened in fights on several occasions usually had a high dominance index. Members of the herd which were observed intervening only once had an average dominance index in both herds of almost 0.5. In some cases, goats very low in the rank order intervened a fight. Only rarely did the intervenors have a lower dominance index than the two fighters. In 103 cases, the direct dominance relationship between a fighting animal and the intervenor was known. In 95 cases (92.2%), the intervenor was dominant to the herd member in this fight and in just eight cases (7.8%), it was subordinate. It could not be determined what advantage the intervenor gained from its activity. It is possible that, at least in certain cases, a particularly relationship existed between the intervenor and one of the fighters.  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5236  
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Author Dugatkin, L.A. url  doi
openurl 
  Title Breaking up fights between others: a model of intervention behaviour Type Journal Article
  Year 1998 Publication Proceedings of the Royal Society of London. Series B: Biological Sciences Abbreviated Journal Proc. R. Soc. Lond. B  
  Volume 265 Issue 1394 Pages 433-437  
  Keywords  
  Abstract To examine when and why animals break up fights between others in their group, I modelled whether ‘winner’ and ‘loser’ effects might be one element driving the evolution of intervention behaviour. I considered one particular type of intervention: when the intervener simply breaks up fights between two others, but does not favour either party in so doing. When victories at time T + 1 are more likely given a victory at time T (i.e. winner effects), intervention is often favoured. Intervention is favoured in these circumstances because the intervening party in essence stops others from ‘getting on a roll’ and climbing up any hierarchy that exists. However, when loser effects alone are at work (defeats at time T + 1 are more likely given a defeat at time T), breaking up fights between others is never selected. If both winner and loser effects are operating simultaneously, then the likelihood of intervention behaviour evolving is a function of the relative strength of these two effects. The greater the winner effect relative to the loser effect, the more likely intervention behaviour is to evolve.  
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  Notes 10.1098/rspb.1998.0313 Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5240  
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Author Henzi, S.P.; Lycett, J.E.; Weingrill, T. url  doi
openurl 
  Title Mate guarding and risk assessment by male mountain baboons during inter-troop encounters Type Journal Article
  Year 1998 Publication Animal Behaviour. Abbreviated Journal Anim. Behav.  
  Volume 55 Issue 6 Pages 1421-1428  
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  Abstract Aggressive herding of females is a frequent but not invariant response by male savannah baboons,Papio cynocephalus, to encounters with other troops. While males in some troops are consistently more likely to herd than those in others, not all inter-troop encounters result in herding, even within particular troops. This suggests that males assess the risk of male invasion posed by each encounter and respond accordingly. We used data from baboon troops in the Drakensberg mountains to determine the rules males follow in deciding whether to herd. Consistent differences between troops were explained only by the adult sex ratio. Males were more likely to herd if the sex ratio of their own troop was female biased, a finding that is concordant with the observation that males are more likely to immigrate into troops where the sex ratio is more female biased than the population average. Differences within troops were a consequence only of encounter distance, with herding being more likely at closer distances. We found a negative correlation between the angle of approach to the other troop and the subsequent angle of deflection. We interpret this to mean that herding functions to increase the distance between the interacting troops, thereby curtailing opportunities for strange males to inspect the troop and determine its sex ratio. In this way, possibly unlike those in other populations, the decision rules of these male baboons are geared to protecting longer-term reproductive prospects.  
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  ISSN 0003-3472 ISBN Medium  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5311  
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Author Wittling, W.; Block, A.; Schweiger, E.; Genzel, S. url  doi
openurl 
  Title Hemisphere Asymmetry in Sympathetic Control of the Human Myocardium Type Journal Article
  Year 1998 Publication Brain and Cognition Abbreviated Journal Brain Cogn.  
  Volume 38 Issue 1 Pages 17-35  
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  Abstract Hemisphere asymmetry in sympathetic control of myocardial performance was studied in healthy human subjects using lateralized film presentation for selective sensory stimulation of the hemispheres and impedance cardiography for the evaluation of cardiac output, systolic time intervals and myocardial contractility. Results revealed a clear and consistent right hemisphere predominance in sympathetically mediated control of various components of myocardial performance. There is reason to assume that the obtained hemisphere differences in autonomic control of the heart are self-reliant processes not depending on emotion-related hemisphere asymmetry. As far as we know, this is the first study examining the distinct roles of the cerebral hemispheres in neural control of ventricular myocardial functions.  
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  ISSN 0278-2626 ISBN Medium  
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  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5351  
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Author Potts, R. doi  openurl
  Title Variability selection in hominid evolution Type Journal Article
  Year 1998 Publication Evolutionary Anthropology: Issues, News, and Reviews Abbreviated Journal Evol. Anthropol.  
  Volume 7 Issue 3 Pages 81-96  
  Keywords variability selection; hominids; environment; adaptation; natural selection; evolution  
  Abstract Variability selection (abbreviated as VS) is a process considered to link adaptive change to large degrees of environment variability. Its application to hominid evolution is based, in part, on the pronounced rise in environmental remodeling that took place over the past several million years. The VS hypothesis differs from prior views of hominid evolution, which stress the consistent selective effects associated with specific habitats or directional trends (e.g., woodland, savanna expansion, cooling). According to the VS hypothesis, wide fluctuations over time created a growing disparity in adaptive conditions. Inconsistency in selection eventually caused habitat-specific adaptations to be replaced by structures and behaviors responsive to complex environmental change. Key hominid adaptations, in fact, emerged during times of heightened variability. Early bipedality, encephalized brains, and complex human sociality appear to signify a sequence of VS adaptations—i.e., a ratcheting up of versatility and responsiveness to novel environments experienced over the past 6 million years. The adaptive results of VS cannot be extrapolated from selection within a single environmental shift or relatively stable habitat. If some complex traits indeed require disparities in adaptive setting (and relative fitness) in order to evolve, the VS idea counters the prevailing view that adaptive change necessitates long-term, directional consistency in selection. © 1998 Wiley-Liss, Inc.  
  Address  
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  Publisher John Wiley & Sons, Inc. Place of Publication Editor  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1520-6505 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number (up) Equine Behaviour @ team @ Serial 5461  
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