Abstract: The object of this study was to determine the limb support sequence during the transitions from walk to trot and from trot to walk in dressage horses under saddle and to test the null hypothesis that the limb support sequence during the transitions is not related to the level of training. Sixteen dressage horses training at novice to FEI Grand Prix level were videotaped performing an average of 9 transitions each from walk to trot and from trot to walk. The 30-Hz videotapes were viewed in slow motion, and based on the limb support sequence the transitions were categorized into two types. In type 1 transitions there were no intermediate steps between the walk and trot sequences. Type 2 transitions were characterized by intermediate steps, including a single support phase. The Kendall rank-order correlation coefficient showed that a higher level of training was positively associated with an increased percentage of type 1 transitions for both walk-to-trot transitions (p < or = 0.05) and trot-to-walk transitions (p < or = 0.01). No significant preference for initiating or completing the trot on the left or right diagonal was found using the binomial test for individual horses and the Wilcoxon signed-ranks test for the group.

Abstract: Abstract. Competition for food is thought to play a key role in the social organization of group-living female primates, leading to the prediction that individual foraging success will be partly regulated by dominance relationships. Among adult females in a group of free-ranging olive baboons, dominance rank was significantly correlated with nutrient acquisition rates (feeding rates and daily intakes), but not with dietary diversity or quality, nor with activity budgets. The mean daily food intake of the three highest-ranking females was 30% greater than that of the three lowest-ranking females, providing an explanation for relationships between female rank and fertility found in a number of other studies of group-living primates. The intensity of feeding competition, as measured by supplant rates and spatial clustering of individuals, increased during the dry season, a period of low food availability, seemingly because foods eaten then were more clumped in distribution than those eaten in the wet season. Implications for models of female social structure and maximum group size are discussed.

Abstract: Four experiments were designed to find evidence of observational learning in cattle. The experiments were run on ten experimental heifers, each observing a demonstrator mate performing a task, and on ten control heifers, each observing a non-demonstrator mate. The mates and observers were separated by wire netting in Experiments 1-3, but were in the same room in Experiment 4. The task to be learned was to push a panel to get food into a box. All naive animals were able to observe while their mate performed the task. The observers in Experiments 1 and 4 were Salers heifers that had no prior experience of the testing room; those in Experiment 2 were Salers heifers that were accustomed to the room; those in Experiment 3 were Aubrac or Limousin heifers that had already eaten in the room.
The behaviour of the observers was influenced by their mates: activity at or near the boxes was enhanced by the presence of demonstrators in Experiment 2 (box contacts: 38.0 +/- 16.2 vs. 22.1 +/- 11.9 for experimental and control heifers, respectively; P<0.05), while activity in other parts of the room in Experiment 3 was enhanced when non-demonstrator mates were present (wall sniffing: 5.4 +/- 13.9 vs. 13.9 +/- 13.7; P<0.05). Overall, 26 experimental heifers vs. 19 controls learned the task (P>0.05). The time spent eating was longer when the observer only had visual contact with a demonstrator (Experiment 1: 15.9 +/- 1.6 vs. 11.6 +/- 1.8 min), but was lower when physical contacts with the demonstrator were possible (Experiment 4: 4.6 +/- 8.8 vs. 5.4 +/- 2.2 min; P<0.05).
Ten out of the 11 Limousin heifers learned the task, compared with only three out of the nine Aubrac heifers (P<0.05). The latter spent more time near the door and sniffed the walls more often than the former (2.0 +/- 1.9 vs. 0.4 +/- 0.6 min, P<0.05, and 18.1 +/- 13.4 vs. 2.7 +/- 6.5 min, P<0.01), as though they were trying to flee the situation.
When animals observed a demonstrator, their attention was drawn to stimuli involved in the task but acquisition of knowledge was not greatly improved.

Abstract: In a two-choice discrimination paradigm, a bottlenose dolphin discriminated relational dimensions between visual numerosity stimuli under monocular viewing conditions. After prior binocular acquisition of the task, two monocular test series with different number stimuli were conducted. In accordance with recent studies on visual lateralization in the bottlenose dolphin, our results revealed an overall advantage of the right visual field. Due to the complete decussation of the optic nerve fibers, this suggests a specialization of the left hemisphere for analysing relational features between stimuli as required in tests for numerical abilities. These processes are typically right hemisphere-based in other mammals (including humans) and birds. The present data provide further evidence for a general right visual field advantage in bottlenose dolphins for visual information processing. It is thus assumed that dolphins possess a unique functional architecture of their cerebral asymmetries.

Abstract: : This article presents a meta-analysis of the literature on stress and immunity in humans. The primary analyses include all relevant studies irrespective of the measure or manipulation of stress. The results of these analyses show substantial evidence for a relation between stress and decreases in functional immune measures (proliferative response to mitogens and natural killer cell activity). Stress is also related to numbers and percent of circulating white blood cells, immunoglobulin levels, and antibody titers to herpesviruses. Subsequent analyses suggest that objective stressful events are related to larger immune changes than subjective self-reports of stress, that immune response varies with stressor duration, and that interpersonal events are related to different immune outcomes than nonsocial events. We discuss the way neuroendocrine mechanisms and health practices might explain immune alteration following stress, and outline issues that need to be investigated in this area. Copyright (C) 1993 by American Psychosomatic Society