Entrainment and Unit Velocity: Surprises in an Accelerated Exclusion Process

We introduce a class of distance-dependent interactions in an accelerated exclusion process inspired by the observation of transcribing RNA polymerase speeding up when “pushed” by a trailing one. On a ring, the accelerated exclusion process steady state displays a discontinuous transition, from being homogeneous (with augmented currents) to phase segregated. In the latter state, the holes appear loosely bound and move together, much like a train. Surprisingly, the current-density relation is simply J=1-ρ, signifying that the “hole train” travels with unit velocity.

Entrainment and Unit Velocity: Surprises in an Accelerated Exclusion Process

We introduce a class of distance-dependent interactions in an accelerated exclusion process inspired by the observation of transcribing RNA polymerase speeding up when “pushed” by a trailing one. On a ring, the accelerated exclusion process steady state displays a discontinuous transition, from being homogeneous (with augmented currents) to phase segregated. In the latter state, the holes appear loosely bound and move together, much like a train. Surprisingly, the current-density relation is simply J=1-ρ, signifying that the “hole train” travels with unit velocity.

Applied Developmental Psychology as an Implementation of the Life-Span View of Human Development

Application of knowledge about psychological development should, ideally, be theory based. As such, these applications represent “natural ontogenetic experiments”; the results of the evaluation of such interventions feed back to the theory, helping to support, falsify, or refine the ideas from the theory which led to the particular application. Such applied developmental intervention research is central within a currently popular perspective of life-span human development. Thus, applied developmental intervention research provides critical tests of such key concepts within this life-span perspective as: plasticity; multidirectionality; the synthesis of continuous and discontinuous processes across ontogeny; contextual embeddedness; and the role of individuals as agents in their own development. This paper elucidates some of the major features of the dynamic linkage between applied developmental psychology and this view of life-span human development. Key elements of this life-span perspective and the facts of developmental intervention, as seen from this perspective, are specified. Finally, the doctoral training program at the authors' institution is presented as one example of how this link may be institutionalized in the form of graduate education.