AT dogs had increased mechanical asymmetry at 4 and 8 weeks compared to the CM group revealing surgery worsened limb function. There was no significant difference in mechanical symmetry between groups at 26 and 52 weeks.

Sound trotting dogs can have asymmetries in limb and joint mechanics. These natural mechanical asymmetries should be taken into account when considering models to evaluate stresses at joints and when considering surgery for cruciate ligament rupture.

The role of affective correspondence between signal and outcome in associative learning was studied in 2 experiments with 4-month-olds. In Experiment 1, an infant-directed (ID) speech segment, categorized by adults as having consoling acoustic properties for infants, was either paired or unpaired with smiling or sad face reinforcers. In other groups, a sad adult-directed (AD) speech segment signaled the smiling or sad faces. Later, all speech segments were tested for their ability to increase infants' visual interest in a checkerboard. Positive summation was observed only when the consoling ID speech segment had signaled the sad face. In Experiment 2, an arousing ID speech segment signaled the smiling or sad face. Positive summation was evident in both conditions. These results show that infants sometimes selectively associate speech segments and faces. Discussion centers on the basis for the selective association.

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