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Blaisdell, A. P., Sawa, K., Leising, K. J., & Waldmann, M. R. (2006). Causal reasoning in rats. Science, 311(5763), 1020–1022.
Abstract: Empirical research with nonhuman primates appears to support the view that causal reasoning is a key cognitive faculty that divides humans from animals. The claim is that animals approximate causal learning using associative processes. The present results cast doubt on that conclusion. Rats made causal inferences in a basic task that taps into core features of causal reasoning without requiring complex physical knowledge. They derived predictions of the outcomes of interventions after passive observational learning of different kinds of causal models. These competencies cannot be explained by current associative theories but are consistent with causal Bayes net theories.
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Permyakov, S. E., Khokhlova, T. I., Nazipova, A. A., Zhadan, A. P., Morozova-Roche, L. A., & Permyakov, E. A. (2006). Calcium-binding and temperature induced transitions in equine lysozyme: new insights from the pCa-temperature “phase diagrams”. Proteins, 65(4), 984–998.
Abstract: The most universal approach to the studies of metal binding properties of single-site metal binding proteins, i.e., construction of a “phase diagram” in coordinates of free metal ion concentration-temperature, has been applied to equine lysozyme (EQL). EQL has one relatively strong calcium binding site and shows two thermal transitions, but only one of them is Ca(2+)-dependent. It has been found that the Ca(2+)-dependent behavior of the low temperature thermal transition (I) of EQL can be adequately described based upon the simplest four-states scheme of metal- and temperature-induced structural changes in a protein. All thermodynamic parameters of this scheme were determined experimentally and used for construction of the EQL phase diagram in the pCa-temperature space. Comparison of the phase diagram with that for alpha-lactalbumin (alpha-LA), a close homologue of lysozyme, allows visualization of the differences in thermodynamic behavior of the two proteins. The thermal stability of apo-EQL (transition I) closely resembles that for apo-alpha-LA (mid-temperature 25 degrees C), while the thermal stabilities of their Ca(2+)-bound forms are almost indistinguishable. The native state of EQL has three orders of magnitude lower affinity for Ca(2+) in comparison with alpha-LA while its thermally unfolded state (after the I transition) has about one order lower (K = 15M(-1)) affinity for calcium. Circular dichroism studies of the apo-lysozyme state after the first thermal transition show that it shares common features with the molten globule state of alpha-LA.
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Balenghien, T., Fouque, F., Sabatier, P., & Bicout, D. J. (2006). Horse-, bird-, and human-seeking behavior and seasonal abundance of mosquitoes in a West Nile virus focus of southern France. J Med Entomol, 43(5), 936–946.
Abstract: After 35 yr of disease absence, West Nile virus (family Flaviviridae, genus Flavivirus, WNV) circulation has been regularly detected in the Camargue region (southern France) since 2000. WNV was isolated from Culex modestus Ficalbi, which was considered the main vector in southern France after horse outbreaks in the 1960s. Recent WNV transmissions outside of the Cx. modestus distribution suggested the existence of other vectors. To study potential WNV vectors, horse- and bird-baited traps and human landing collections of mosquitoes were carried out weekly from May to October 2004 at two Camargue sites: one site in a wet area and the other site in a dry area, both chosen for their past history of WNV transmission. At the wet site, the most abundant species in bird-baited traps were Culex pipiens L. and Cx. modestus; both species also were found in lower proportions on horses and humans. The most abundant species in horse-baited traps and human landing collections were Aedes caspius (Pallas), Aedes vexans (Meigen), and Anopheles hyrcanus (Pallas) sensu lato; some of these species were occasionally collected with avian blood at the end of the summer. Anopheles maculipennis Meigen sensu lato was an abundant horse feeder, but it was rarely collected landing on human bait and never contained avian blood. At the dry site, Cx. pipiens was the most abundant species in bird- and horse-baited traps. The seasonal and circadian dynamics of these species are analyzed, and their potential in WNV transmission in Camargue discussed.
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Wittemyer, G., & Getz, W. M. (2006). A likely ranking interpolation for resolving dominance orders in systems with unknown relationships. Behaviour, 143(7), 909–930.
Abstract: n many animal systems agonistic interactions may be rare or not overt, particularly where such interactions are costly or of high risk as is common for large mammals. We present a technique developed specifically for resolving an optimized dominance order of individuals in systems with transitive (i.e. linear) dominance relationships, but where not all relationships are known. Our method augments the widely used I&SI method (de Vries, 1998) with an interpolation function for resolving the relative ranks of individuals with unknown relationships. Our method offers several advantages over other dominance methods by enabling the incorporation of any proportion of unknown relationships, resolving a unique solution to any dominance matrix, and calculating cardinal dominance strengths for each individual. As such, this method enables novel insight into difficult to study behavioural systems.
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Krcmar, S., & Maric, S. (2006). Analysis of the feeding sites for some horse flies (Diptera, Tabanidae) on a human in Croatia. Coll Antropol, 30(4), 901–904.
Abstract: The landing patterns of horse flies on the human body were observed in Croatia. A total of 386 horse flies belonging to 22 species were sampled. The five most commonly collected species were used in the analysis. The stochastic linear connection is tight among the landings of the species Tabanus bromius, Tabanus maculicornis, Tabanus tergestinus, and Philipomyia graeca on the human body regions (matrix R). The preferred feeding area for these four species was the lower leg, whereas for the species Haematopota pluvialis it was the head and neck. Of the total number of horse flies that landed 44.81% were on the lower leg. Only 0.26% landed on the forearm. Chi-square analysis indicated non random landing patterns on human by these horse flies.
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Grange, S., & Duncan, P. (2006). Bottom-up and top-down processes in African ungulate communities: resources and predation acting on the relative abundance of zebra and grazing bovids. Ecography, 29(6), 899–907.
Abstract: African ungulate populations appear to be limited principally by their food resources. Within ungulate communities, plains zebras coexist with grazing bovids of similar body size, but rarely are the dominant species. Given the highly effective nutritional strategy of the equids and the resistance of zebras to drought, this is unexpected and suggests that zebra populations may commonly be limited by other mechanisms. Long-term research in the Serengeti ecosystem and in the Kruger National Park suggests that zebra could be less sensitive to food shortage, and more sensitive to predation, than grazing bovids: if this is a general principle, then, at a larger scale, resource availability should have a weaker effect on the abundance of zebra than on grazing ruminants of similar body size (wildebeest and buffalo), and zebras should be relatively more abundant in ecosystems where predators are rare or absent. We test these expectations using data on 23 near-natural ecosystems in east and southern Africa. The abundance of wildebeest is more closely related to resources than is that of zebra; buffalo are intermediate. We show that hyena densities are closely correlated with those of lions, and use the abundance of lions as an index of predation by large predators. The numerical response of lions to increases in the abundance of their prey was linear for mesoherbivores, and apparently so for the three species alone. Finally, the abundance of zebra relative to grazing bovids is lower in ecosystems with high biomasses of lions. These results indicate that zebras may commonly be more sensitive to top-down processes than grazing bovids: the mechanism(s) have not been demonstrated, but predation could play a role. If it is true, then when numbers of the large mammalian predators decline, zebra populations should increase faster than buffalo and wildebeest.
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Rosell, F., & Sanda, J. I. (2006). Potential risks of olfactory signaling: the effect of predators on scent marking by beavers. Behav. Ecol., 17(6), 897–904.
Abstract: Mammals scent mark their territories to advertise occupancy and ownership. However, signaling with scent for territorial defense can have a negative effect by advertising an individual's presence and location to predators. In this study, we measured responses to a simulated territorial intrusion by conspecific adult male Eurasian beavers (Castor fiber) either in the localized presence or in the absence of odor of a predator to test the hypothesis that the territorial defense of free-living beavers would be disrupted by the presence of predation risk in their natural environment. We predicted that beavers would significantly reduce their willingness to countermark intruder's scent in the presence of the scent of predators (wolf [Canis lupus] and lynx [Lynx lynx]), compared with a control (no odor), as responses are in general stronger to predator scent marks than nonpredator scent. Therefore, we also predicted that the effects of nonpredatory mammal scent (neophobic control) (eland [Taurotragus oryx] and horse [Equus cabalus]) are to be expected somewhere in between the effects of the predator odor and a control. Our results suggest that both predator and nonpredator scents reduce beavers response to a simulated intruder's scent mounds and therefore disrupt their territorial defense. However, predator scent had a stronger effect than nonpredator scent. Beavers may therefore be at great risk on territories with predators present because of the trade-off between predator avoidance and territorial defense. Our study demonstrates the potential of predation risk as a powerful agent of counterselection on olfactory signaling behavior.
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Milinovich, G. J., Trott, D. J., Burrell, P. C., van Eps, A. W., Thoefner, M. B., Blackall, L. L., et al. (2006). Changes in equine hindgut bacterial populations during oligofructose-induced laminitis. Environ Microbiol, 8(5), 885–898.
Abstract: In the horse, carbohydrate overload is thought to play an integral role in the onset of laminitis by drastically altering the profile of bacterial populations in the hindgut. The objectives of this study were to develop and validate microbial ecology methods to monitor changes in bacterial populations throughout the course of experimentally induced laminitis and to identify the predominant oligofructose-utilizing organisms. Laminitis was induced in five horses by administration of oligofructose. Faecal specimens were collected at 8 h intervals from 72 h before to 72 h after the administration of oligofructose. Hindgut microbiota able to utilize oligofructose were enumerated throughout the course of the experiment using habitat-simulating medium. Isolates were collected and representatives identified by 16S rRNA gene sequencing. The majority of these isolates collected belonged to the genus Streptococcus, 91% of which were identified as being most closely related to Streptococcus infantarius ssp. coli. Furthermore, S. infantarius ssp. coli was the predominant oligofructose-utilizing organism isolated before the onset of lameness. Fluorescence in situ hybridization probes developed to specifically target the isolated Streptococcus spp. demonstrated marked population increases between 8 and 16 h post oligofructose administration. This was followed by a rapid population decline which corresponded with a sharp decline in faecal pH and subsequently lameness at 24-32 h post oligofructose administration. This research suggests that streptococci within the Streptococcus bovis/equinus complex may be involved in the series of events which precede the onset of laminitis in the horse.
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Huxley, J. (2006). Equine interspecies aggression (Vol. 159).
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Burden, F., & Trawford, A. (2006). Equine interspecies aggression Comment on (Vol. 159).
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