Stationary states of a spherical Minority Game with ergodicity breaking

Using generating functional and replica techniques, respectively, we study the dynamics and statics of a spherical Minority Game (MG), which in contrast with a spherical MG previously presented in J.Phys A: Math. Gen. 36 11159 (2003) displays a phase with broken ergodicity and dependence of the macroscopic stationary state on initial conditions. The model thus bears more similarity with the original MG. Still, all order parameters including the volatility can computed in the ergodic phases without making any approximations. We also study the effects of market impact correction on the phase diagram. Finally we discuss a continuous-time version of the model as well as the differences between on-line and batch update rules. Our analytical results are confirmed convincingly by comparison with numerical simulations. In an appendix we extend the analysis of the earlier spherical MG to a model with general time-step, and compare the dynamics and statics of the two spherical models.Comment: 26 pages, 8 figures; typo correcte

How the Belgian wind farm business made us discover the challenging environment of marine sand dunes

During the last decade, it has become clear that sand dunes are important features in the Belgian wind farm concession area. Because they influence not only the design seabed levels, but also the hydrodynamic forcings and installation methods for both cable and foundations, the study of the seabed morphodynamics is essential for all wind farm projects. This paper starts with an overview of the geographic and morphological setting of the Belgian wind farm concession areas and presents an overview of the key features of the bedforms in the different concessions. Next the importance and impact of the sand dunes during the design and development of these wind farms is illustrated by exploring the different types of studies and investigations which have been performed in relation to seabed & morphology, the hydrodynamic loadings, the installation methods and the environmental impact assessments

Perspectives on Systematic Analyses of Gene Function in Arabidopsis thaliana: New Tools, Topics and Trends

Since the sequencing of the nuclear genome of Arabidopsis thaliana ten years ago, various large-scale analyses of gene function have been performed in this model species. In particular, the availability of collections of lines harbouring random T-DNA or transposon insertions, which include mutants for almost all of the ~27,000 A. thaliana genes, has been crucial for the success of forward and reverse genetic approaches. In the foreseeable future, genome-wide phenotypic data from mutant analyses will become available for Arabidopsis, and will stimulate a flood of novel in-depth gene-function analyses. In this review, we consider the present status of resources and concepts for systematic studies of gene function in A. thaliana. Current perspectives on the utility of loss-of-function and gain-of-function mutants will be discussed in light of the genetic and functional redundancy of many A. thaliana genes

Numerical modelling of the extreme wave climate in the Belgian harbours: part 3. Marina of Blankenberge

The design of water and wave retaining walls and flood risk analyses need hydrodynamic boundary conditions. These boundary conditions are needed during a storm with return period 1000yrs and during the super storms which were defined in the risk analysis study. The modelling of the extreme wave climate is decoupled to the wave penetration and the lacal generation of waves by the extreme wind speed. The wave penetration is modelled with Mike 21 BW as was done for Oostende and Zeebrugge. MILDwave is not used this time because non-linear effects (e.g. long wave generation, wave setup) are too important in this case. Instead another nonlinear model SWASH is applied. The modelling of local generation of waves by wind is still done with the spectral model SWAN.First the bathymetry files are created based on the dredging plan of Blankenberge marina, and all the suitable settings used for the Mike 21 BW and the SWASH are investigated. Since SWASH model does not have so much application examples, Wenduine physical model is used to validate the model. Consequently, a sensitivity analysis is conducted for both models to study which parameter is important for the wave climate inside the marina. The most severe offshore wave direction for the design of the wave retaining walls is decided based on the 1000 year storm. After the calculation of the wave penetration in the case of 1000 year storm and +7.9 mTAW storm, locally generated wind waves are also simulated by SWAN. All extreme wind speeds and directions for the 1000-year storm and the super storms are modelled. Finally, long and short wave energy of the wave penetration models is separated and a superposition of the short wave energy and the SWAN model is done to obtain the total extreme wave climate in the marina of Blankenberge. The maximum surface elevation of the long wave energy and the wave setup provide an increase of the still water level to take into account for design purpose