منابع مشابه
Absolute Expediency and Imitative Behaviour
This paper analyses a model of learning by imitation, where besides the decision maker, there is a population of individuals facing the same decision problem. We analyse a property called Absolute Expediency, which requires that the decision maker’s expected payo¤ increases from one round to the next for every decision problem and every state of the population. We give a simple characterisation...
متن کاملThe STAR automaton: expediency and optimality properties
We present the STack ARchitecture (STAR) automaton. It is a fixed structure, multiaction, reward-penalty learning automaton, characterized by a star-shaped state transition diagram. Each branch of the star contains D states associated with a particular action. The branches are connected to a central "neutral" state. The most general version of STAR involves probabilistic state transitions in re...
متن کاملForty million years of mutualism: evidence for eocene origin of the yucca-yucca moth association.
The obligate mutualism between yuccas and yucca moths is a major model system for the study of coevolving species interactions. Exploration of the processes that have generated current diversity and associations within this mutualism requires robust phylogenies and timelines for both moths and yuccas. Here we establish a molecular clock for the moths based on mtDNA and use it to estimate the ti...
متن کاملFlorivores Limit Cost of Mutualism in the Yucca–yucca Moth Association
Multispecies interactions may have important consequences for the ecology and evolution of mutualism by changing the cost-to-benefit ratio. Here I determine whether florivorous beetles can limit moth populations and influence the costs of the mutualism between yuccas and their pollinating moths. Yucca moths actively pollinate yucca flowers, and their larvae feed on a portion of the seeds. I use...
متن کاملWildfire , timber salvage , and the economics of expediency Jeffrey
Administrative planning rules and legal challenges can have significant economic impacts on timber salvage programs on public lands. This paper examines the costs of the delay in salvage caused by planning rules and the costs associated with the volume reductions forced by legal challenges in one case study. The fires on the Bitterroot National Forest in the northern Rocky Mountains in the Unit...
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ژورنال
عنوان ژورنال: Nature
سال: 1994
ISSN: 0028-0836,1476-4687
DOI: 10.1038/368588a0