New analytical results in the electromagnetic response of composite superconducting wire in parallel fields

Analytical results are presented concerning the electromagnetic response of a composite superconducting wire in fields parallel to the wire axis, using the Maxwell equations supplemented with constitutive equations. The problem is nonlinear due to the nonlinearity in the constitutive equation describing the superconducting filaments. It is shown that the nonlinear behavior of the wire can be studied by analytical means. The method used gives an exact description of the response of a wire with nonconducting matrix material surrounding filaments with zero filament radius. For a composite wire it provides a very good approximatio

Identifying the gap between stated and actual buying behaviour on organic products based on consumer panel data

Evaluating the German demand for organic food in the majority of cases has been done by interviews, which are restricted by massive overestimation of consumers themselves. By using consumer panels, it is possible to survey actual consumer behaviour in combination with consumer attitudes and socio-demographic data and also by additionally requested consumers’ stated buying behaviour. Such methodology enables exposure and quantification of the gap between stated and actual buying frequency. Also the dimension of conventional products bought by mistake, while intending to get organics, can be identified. These results may give considerations for prospective survey design and adjustment of marketing policy

The phase diagram of the multi-dimensional Anderson localization via analytic determination of Lyapunov exponents

The method proposed by the present authors to deal analytically with the problem of Anderson localization via disorder [J.Phys.: Condens. Matter {\bf 14} (2002) 13777] is generalized for higher spatial dimensions D. In this way the generalized Lyapunov exponents for diagonal correlators of the wave function, $$, can be calculated analytically and exactly. This permits to determine the phase diagram of the system. For all dimensions $D > 2$ one finds intervals in the energy and the disorder where extended and localized states coexist: the metal-insulator transition should thus be interpreted as a first-order transition. The qualitative differences permit to group the systems into two classes: low-dimensional systems ($2\leq D \leq 3$), where localized states are always exponentially localized and high-dimensional systems ($D\geq D_c=4$), where states with non-exponential localization are also formed. The value of the upper critical dimension is found to be $D_0=6$ for the Anderson localization problem; this value is also characteristic of a related problem - percolation.Comment: 17 pages, 5 figures, to appear in Eur. Phys.J.

Developing the Research Infrastructure in the Social Sciences: The Role and Contribution of the German Research Foundation

The DFG’s (German Research Foundation) strategy for future data research infrastructures should be based on what has been achieved thus far and the lessons that can be learned: First, the focus should be on “providing data” rather than on “sharing data.” Second, projects whose primary purpose is to provide a common good should seek to build research infrastructure. The DFG has powerful means at its disposal for funding outstanding infrastructure projects. It is up to the scientific community to adapt and utilize these funding instruments. Strategic cooperation is required among all the interested parties in the field: cooperation on thematic priorities within the research community; cooperation on options for funding between the research community and funding institutions; cooperation on the division of labour between the funding institutions (including ministries), both on the national and on the international level. The DFG is prepared to play an active role in this cooperation under the leadership of its elected bodies (Fachkollegien and Senat).Large Scale Studies; Strategic Cooperation