Perspective: network-guided pattern formation of neural dynamics

The understanding of neural activity patterns is fundamentally linked to an understanding of how the brain's network architecture shapes dynamical processes. Established approaches rely mostly on deviations of a given network from certain classes of random graphs. Hypotheses about the supposed role of prominent topological features (for instance, the roles of modularity, network motifs, or hierarchical network organization) are derived from these deviations. An alternative strategy could be to study deviations of network architectures from regular graphs (rings, lattices) and consider the implications of such deviations for self-organized dynamic patterns on the network. Following this strategy, we draw on the theory of spatiotemporal pattern formation and propose a novel perspective for analyzing dynamics on networks, by evaluating how the self-organized dynamics are confined by network architecture to a small set of permissible collective states. In particular, we discuss the role of prominent topological features of brain connectivity, such as hubs, modules and hierarchy, in shaping activity patterns. We illustrate the notion of network-guided pattern formation with numerical simulations and outline how it can facilitate the understanding of neural dynamics

Internationalisation of Innovation: Why Chip Design Moving to Asia

This paper will appear in International Journal of Innovation Management, special issue in honor of Keith Pavitt, (Peter Augsdoerfer, Jonathan Sapsed, and James Utterback, guest editors), forthcoming. Among Keith Pavitt's many contributions to the study of innovation is the proposition that physical proximity is advantageous for innovative activities that involve highly complex technological knowledge But chip design, a process that creates the greatest value in the electronics industry and that requires highly complex knowledge, is experiencing a massive dispersion to leading Asian electronics exporting countries. To explain why chip design is moving to Asia, the paper draws on interviews with 60 companies and 15 research institutions that are doing leading-edge chip design in Asia. I demonstrate that "pull" and "policy" factors explain what attracts design to particular locations. But to get to the root causes that shift the balance in favor of geographical decentralization, I examine "push" factors, i.e. changes in design methodology ("system-on-chip design") and organization ("vertical specialization" within global design networks). The resultant increase in knowledge mobility explains why chip design - that, in Pavitt's framework is not supposed to move - is moving from the traditional centers to a few new specialized design clusters in Asia. A completely revised and updated version has been published as: " Complexity and Internationalisation of Innovation: Why is Chip Design Moving to Asia?," in International Journal of Innovation Management, special issue in honour of Keith Pavitt, Vol. 9,1: 47-73.

A Biologically Informed Hylomorphism

Although contemporary metaphysics has recently undergone a neo-Aristotelian revival wherein dispositions, or capacities are now commonplace in empirically grounded ontologies, being routinely utilised in theories of causality and modality, a central Aristotelian concept has yet to be given serious attention – the doctrine of hylomorphism. The reason for this is clear: while the Aristotelian ontological distinction between actuality and potentiality has proven to be a fruitful conceptual framework with which to model the operation of the natural world, the distinction between form and matter has yet to similarly earn its keep. In this chapter, I offer a first step toward showing that the hylomorphic framework is up to that task. To do so, I return to the birthplace of that doctrine - the biological realm. Utilising recent advances in developmental biology, I argue that the hylomorphic framework is an empirically adequate and conceptually rich explanatory schema with which to model the nature of organism

A Model of Genome Size Evolution for Prokaryotes in Stable and Fluctuating Environments

Temporal variability in ecosystems significantly impacts species diversity and ecosystem productivity and therefore the evolution of organisms. Different levels of environmental perturbations such as seasonal fluctuations, natural disasters, and global change have different impacts on organisms and therefore their ability to acclimatize and adapt. Thus, to understand howorganisms evolve under different perturbations is a key for predicting how environmental change will impact species diversity and ecosystem productivity. Here, we developed a computer simulation utilizing the individual-based model approach to investigate genome size evolution of a haploid, clonal and free-living prokaryotic population across different levels of environmental perturbations. Our results showthat a greater variability of the environment resulted in genomes with a larger number of genes. Environmental perturbations were more effectively buffered by populations of individuals with relatively large genomes. Unpredictable changes of the environment led to a series of population bottlenecks followed by adaptive radiations. Our model shows that the evolution of genome size is indirectly driven by the temporal variability of the environment. This complements the effects of natural selection directly acting on genome optimization. Furthermore, species that have evolved in relatively stable environments may face the greatest risk of extinction under global change as genome streamlining genetically constrains their ability to acclimatize to the new environmental conditions, unless mechanisms of genetic diversification such as horizontal gene transfer will enrich their gene pool and therefore their potential to adapt