Computational models of learning and beyond: Symmetries of associative learning

The authors propose in this chapter to use abstract algebra to unify different models of theories of associative learning -- as complementary to current psychological, mathematical and computational models of associative learning phenomena and data. The idea is to compare recent research in associative learning to identify the symmetries of behaviour. This approach, a common practice in Physics and Biology, would help us understand the structure of conditioning as opposed to the study of specific linguistic (either natural or formal) expressions that are inherently incomplete and often contradictory

New artificial superlattices: correlation between structural disorder and transport properties

The development of thin film deposition techniques allowed the growth of new artificial materials leading to the discovery of new high Te superconducting compounds as infinite layer based superlattices [(BaCuO2)(m)/(CaCuo(2))(n)]). The order of the superlattice structure seems to be one of the crucial parameters to be improved so as to induce a superconductivity onset in these materials and to make them suitable for technological applications. In this paper we present a study on the correlation between structural disorder and transport properties of several artificial superlattices grown by pulsed laser ablation technique. Our goal was to simulate layered structure of copper oxide superconductors, so as to create new artificial superconducting materials and study charge transfer mechanism. We chose infinite layer phases (SrCuO2, CaCuO2, BaCuO2) for the blocks containing CuO2 planes and doped infinite layer phases (CaCu1-xScxOy, SrCu1-xScxOy, CaCu1-xAgxOy and SrCu1-xAgxOy, with x ranging from 0.1 to 0.2) for the charge reservoir blocks. By means of Reflection High Energy Electron Diffraction (RHEED) and S-rays structural characterization as well as resistivity and Hall effect measurements, we perform a comparative analysis of structural and transport properties of these samples and we tried to explain them in terms of Anderson's theory of disorder