We explore the finite model theory of the characterisation theorems for modal and guarded fragments of first-order logic over transition systems and relational structures of width two. A new construction of locally acyclic bisimilar covers provides a useful analogue of the well known tree-like unravellings that can be used for the purposes of finite model theory. Together with various other finitary bisimulation respecting model transformations, and Ehrenfeucht–Fraïssé game arguments, these covers allow us to upgrade finite approximations for full bisimulation equivalence (...) towards approximations for elementary equivalence. These techniques are used to prove several ramifications of the van Benthem–Rosen characterisation theorem of basic modal logic for refinements of ordinary bisimulation equivalence, both in the sense of classical and of finite model theory. (shrink)

If objective physics is dependent on observer properties as Einstein showed, physical reality becomes an ‘interface reality'. Einstein's principle of observer-relativity is extended to micro motions in the observer. The resulting ‘micro relativity’ can be studied using model universes. In a classical billiard universe, the interface is characterized by ‘micro time reversals'. These time reversals cannot be ‘edited out'. They perturb every small-mass object to be observed. And they perturb every fast-moving object to be observed. The implied ‘action noise’ and (...) a ‘velocity limit', respectively, are reminiscent of Planck's constant and the speed of light , in the real world. To check whether there exists a connection with the real world, the observer temperature can be inserted into the two fundamental constants h and c. This leads to a specific value for the ‘observer diameter’ . Search for a cell class clustered around this size in the brain would amount to a ‘Privacy-of-Physics test'. Four such ‘PoP tests’ can be indicated so far. The idea that certain relational properties of the world may be as observer-private as consciousness, is therefore falsifiable. (shrink)

CHAPTER ONE THE PHILOSOPHER MOSAIC IN NAPLES Ever since the discovery in Torre Annunziata of a duplicate1 of the Villa Albani mosaic showing a group of ...

The cellular capacity to internalise objects, involving attachment, engulfment and uptake, exists in virtually all organisms. Many uptake reactions are associated with cell signalling. However, the mechanical forces that form endocytotic vesicles are not known. We propose a ‘leverage‐mediated’ uptake mechanism involving lateral cross‐linking processes on the cell surface that can generate the configurational energy to create an inverse curvature of the membrane. BioEssays 26:1344–1350, 2004. © 2004 Wiley Periodicals, Inc.

Recent studies suggest that insects use pattern recognition molecules to distinguish prokaryotic pathogens and fungi from “self” structures. Less understood is how the innate immune system of insects recognizes endoparasitic Hymenoptera and other eukaryotic invaders as foreign. Here we discuss candidate recognition factors and the strategies used by parasitoids to overcome host defense responses. We suggest that host–parasitoid systems are important experimental models for studying how the innate immune system of insects recognizes foreign invaders that are phylogenetically more closely related (...) to their hosts. The strategies used by parasitoids suggest that insects may employ “hidden-self” recognition molecules for attacking foreign objects intruding the open circulatory system. BioEssays 23:344–351, 2001. © 2001 John Wiley & Sons, Inc. (shrink)

This study examines the extent to which the highly diverse and volatile Dutch electorate received a diverse offer of political newspaper coverage during the 2006 general election campaign. We measured the level of diversity of five subscription based national newspapers with a partisan history and two free dailies. Two forms of diversity were examined: party diversity and issue diversity. The diversity of party coverage in the free dailies was greater than the diversity across all newspapers. Whereas free dailies paid a (...) relatively large amount of attention to new and opposition parties, traditional newspapers paid a relatively large amount of attention to the parties with whom they were aligned during the period of “pillarization”. Conversely, we only found small differences in the distribution of attention to issues. The diversity of issue coverage across newspapers was larger than the diversity within newspapers. (shrink)