Science Conference. Despite dramatic advances in cancer biology and a widening array of treatment options, cancer continues to cause devastating suffering not only to hundreds of thousands of patients who die of it each year in the United States, but also to some patients who are successfully treated and become cancer survivors. Pain, depression, and fatigue are prominent contributors to suffering in many of these individuals. Clinical research on these symptoms holds out the hope of relief for suffering through better understanding of these symptoms and the development of new, more effective treatments.

The ability of 1-year-old infants to remember the location of a nonvisible target was investigated in 3 experiments. Infants searched for a toy hidden in one of many possible locations within a circular bounded space. The presence, number, and spatial arrangement of local cues or "landmarks" within this space were varied. The results of Experiment 1 showed that search performance was highly successful when a landmark was coincident with the location of the toy ("direct"), but less successful when a landmark was adjacent to the target location ("indirect"). The results of Experiment 2 suggested that search with an indirect landmark may be more fragile than search with no landmarks at all. In Experiments 3a and 3b, 2 different configurations of indirect landmarks were employed; search performance was equally poor with both of these and was inferior to search with no landmarks. It is concluded that infants of this age are able to associate a nonvisible target with a direct landmark and are able to code the distance and direction of a target with respect to themselves or with respect to the larger framework. However, there was no evidence that they can code the distance and direction of a target relative to another object. The difficulty of coding with indirect landmarks is interpreted in terms of cognitive complexity and conflict between spatial strategies.

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In this article, we study transitive flows on manifolds or on manifold-like phase spaces. These are flows in which at least one orbit is dense. By quantifying the nature of the set of dense orbits, a variety of transitivity types is obtained. We explore conditions under which products or 'scaled' products of transitive flows are again transitive. We also investigate a connection between transitivity and topologically strong mixing.