In this paper, we argue that object-oriented models must be able to represent three kinds of taxonomic structures: static subclasses, dynamic subclasses and role classes. If CAR is a static subclass of V EHICLE, then a vehicle that is not a car can never migrate to the CAR subclass. If EMPloyee is a dynamic subclass of PERSON, then a PERSON that is not an employee may migrate to EMP. In both ca...

Our increasingly urbanized society and our technology-mediated lifestyles distance most of us from the biological and non-human physical world. Environmental problems present a challenge for education and outreach because they are inherently complex, interdependent, and interrelated. The need for environmentally literate citizens has never been greater. We need people who can work toward an eco...

Visual search for feature singletons is slowed when a task-irrelevant, but more salient distracter singleton is concurrently presented. While there is a consensus that this distracter interference effect can be influenced by internal system settings, it remains controversial at what stage of processing this influence starts to affect visual coding. Advocates of the "stimulus-driven" view mainta...

Every real algebraic variety is isomorphic to the set of totally mixed Nash equilibria of some three-person game, and also to the set of totally mixed Nash equilibria of an N-person game in which each player has two pure strategies. From the Nash-Tognoli Theorem it follows that every compact differentiable manifold can be encoded as the set of totally mixed Nash equilibria of some game. Moreove...