Positivity of Lyapunov exponents for Anderson-type models on two coupled strings

We study two models of Anderson-type random operators on two deterministically coupled continuous strings. Each model is associated with independent, identically distributed four-by-four symplectic transfer matrices, which describe the asymptotics of solutions. In each case we use a criterion by Gol'dsheid and Margulis (i.e. Zariski denseness of the group generated by the transfer matrices in the group of symplectic matrices) to prove positivity of both leading Lyapunov exponents for most energies. In each case this implies almost sure absence of absolutely continuous spectrum (at all energies in the first model and for sufficiently large energies in the second model). The methods used allow for singularly distributed random parameters, including Bernoulli distributions.Comment: 19 page

Traces in monoidal categories

The main result of this paper is the construction of a trace and a trace pairing for endomorphisms satisfying suitable conditions in a monoidal category. This construction is a common generalization of the trace for endomorphisms of dualizable ob jects in a balanced monoidal category and the trace of nuclear operators on a locally convex topological vector space with the approximation property

A generalization of Gordon's theorem and applications to quasiperiodic Schr\"odinger operators

We prove a criterion for absence of eigenvalues for one-dimensional Schr\"odinger operators. This criterion can be regarded as an $L^1$-version of Gordon's theorem and it has a broader range of application. Absence of eigenvalues is then established for quasiperiodic potentials generated by Liouville frequencies and various types of functions such as step functions, H\"older continuous functions and functions with power-type singularities. The proof is based on Gronwall-type a priori estimates for solutions of Schr\"odinger equations.Comment: 8 page

On the lattice of normal subgroups in ultraproducts of compact simple groups

We prove that the lattice of normal subgroups of ultraproducts of compact simple non-abelian groups is distributive. In the case of ultraproducts of finite simple groups or compact connected simple Lie groups of bounded rank the set of normal subgroups is shown to be linearly ordered by inclusion.Comment: 33 pages, no figures; v3 minor revision, to appear in PLM

Consumer attitudes and expectations of organic wine

Within the European Union-funded research project ORWINE (Organic viticulture and wine-making) a qualitative consumer study was carried out in 2006 in the four case study countries Italy, France, Germany and Switzerland. The aim of the study was to identify consumers’ attitudes and expectations of organic wine. In all case study countries, organic wine has a positive image regarding grape production and wine processing. Furthermore, organic wine is perceived as being healthier compared to conventional wine. However, regarding the sensorial quality, organic wine still faces image problems, although the taste image has improved. Consumers expect that organic wine is healthy, pure and naturally produced. A majority are sceptical of using sulphites and other additives and processing aids in organic wine processing. If organic wine processing is regulated on EU-level, consumers will expect that these rules governing organic wine fit with the image and expectations of organic wine being a “natural” and healthy product, which obtains as much as possible the original attributes and quality