Two canonical wedge problems for the Helmholtz equation

Boundary-transmission problems for two-dimensional Helmholtz equations in a quadrant and its complement, respectively, are considered in a Sobolev space setting. The first problem of a quadrant with Dirichlet condition on one face and transmission condition on the other is solved in closed form for the case where all the quadrants are occupied by the same medium. Unique solvability can also be shown in the case of two different media up to exceptional cases of wave numbers, while the Fredholm property holds in general. In the second problem, transmission conditions are prescribed on both faces. Similar results are obtained in the one-medium case, but the two-media case turns out to be more complicated and the equivalent system of boundary pseudodifferential equations cannot be completely analysed by this reasoning.     

Ellen Gleditsch: Pioneer Woman in Radiochemistry

We present the life and work of the Norwegian scientist Ellen Gleditsch (1879-1968) in the early era of radioactivity. From 1907-1912, Gleditsch worked as Marie Curies assistant in the Laboratoire Curie in Paris on the alleged copper-lithium radioactive transformation and on the radiumuranium ratio, as well as studying chemistry and related subjects at the Sorbonne. Later,in 1913-1914, she worked in Bertram Boltwoods laboratory at Yale University on the half-life of radium. Gleditsch also was concerned with academic opportunities for women, and she became the president of the International Federation of University Women. As a professor, the second female professor in Norway, she initiated a research group on radioactivity at the University of Oslo.     

Rationally designed ligands for asymmetric iridium-catalyzed hydrogenation of olefins

A new class of chiral N,P-ligands for the Ir-catalyzed asymmetric hydrogenation of aryl alkenes has been developed. These new ligands proved to be highly efficient and tolerates a broad range of substrates. The enantiomeric excesses are in the range of the best ever reported. The results can be rationalized with the proposed selectivity model.     

3-dimensionalSU(2) lattice gauge theory in terms of gauge invariant variables

As a first step towards a duality transformation for theSU(2) lattice gauge theory in 3 dimensions, the integration over all gauge variant variables is performed explicitly after introducing gauge invariant auxiliary variables. The resulting new Hamiltonian is complex and involves a sum over closed loops. Each of these loops is confined to an elementary cube of a dual lattice. Like in a previous investigation for theO(4) symmetric Heisenberg ferromagnet Rühl's boson representation is used to derive the result.     

On a nonlinear volterra equation

Nonnegative solutions u of the nonlinear Volterra equation u = a * g(u) (g(0) = 0) in mathematical physics are considered. Under certain assumptions the nonhomogenuous equation u = a * g(u) + ? is studied. Some approximations of nonnegative solutions of the homogenuous equation are considered by the nonnegative solutions of the nonhomogenuous one.