Phenotypic Variation and Bistable Switching in Bacteria

Microbial research generally focuses on clonal populations. However, bacterial cells with identical genotypes frequently display different phenotypes under identical conditions. This microbial cell individuality is receiving increasing attention in the literature because of its impact on cellular differentiation, survival under selective conditions, and the interaction of pathogens with their hosts. It is becoming clear that stochasticity in gene expression in conjunction with the architecture of the gene network that underlies the cellular processes can generate phenotypic variation. An important regulatory mechanism is the so-called positive feedback, in which a system reinforces its own response, for instance by stimulating the production of an activator. Bistability is an interesting and relevant phenomenon, in which two distinct subpopulations of cells showing discrete levels of gene expression coexist in a single culture. In this chapter, we address techniques and approaches used to establish phenotypic variation, and relate three well-characterized examples of bistability to the molecular mechanisms that govern these processes, with a focus on positive feedback.

Genetic Programming for Prediction and Control

The relatively ‘new’ field of genetic programming has received a lot of attention during the last few years. This is because of its potential for generating functions which are able to solve specific problems. This paper begins with an extensive overview of the field, highlighting its power and limitations and providing practical tips and techniques for the successful application of genetic programming in general domains. Following this, emphasis is placed on the application of genetic programming to prediction and control. These two domains are of extreme importance in many disciplines. Results are presented for an oral cancer prediction task and a satellite attitude control problem. Finally, the paper discusses how the convergence of genetic programming can be significantly speeded up through bulk synchronous model parallelisation

Two Contexts for Economics in Competition Law - Justifying Competition Law in the Face of Consumers' Bounded Rationality - Deterrence Effects and Competitive Effects

Competition law accommodates two different contexts within which economics may be applied, each defined by a distinct type of cause-effect relationships. First, there are effects of competition law on business conduct (deterrence effects), embodying the fact that businesses take into account legal sanctions when planning their actions. The field studying these effects is Economic Analysis of Law. Second, there are effects of business conduct on competition (competitive effects), which occur through the influence of businesses with market power on behaviour of their customers, suppliers and competitors. This influence falls within the ambit of Industrial Organization. Awareness of the distinction makes it possible to appreciate certain aspects of the application of economics to competition law issues. For instance, within the discourse on this application, the context of competitive effects receives significantly more attention than the context of deterrence effects. Also the often voiced observation that economics and competition law are closely related regards predominantly the former context