0. Introduction We begin by recalling a well known result of Dennis Sullivan for geodesic excursions on finite area non-compact surfaces V . Let v(t) be position reached after time t > 0 by a vector traveling at unit speed along the geodesic whose initial unit tangent vector was v(0). This following result describes the behaviour of the distance from v(t) to v(0) for typical geodesics as t tend...

We consider the time-dependent nonlinear system q̇(t) = u(t)X(q(t)) + (1 − u(t))Y (q(t)), where q ∈ R, X and Y are two smooth vector fields, globally asymptotically stable at the origin and u : [0,∞) → {0, 1} is an arbitrary measurable function. Analysing the topology of the set where X and Y are parallel, we give some sufficient and some necessary conditions for global asymptotic stability, uni...

It is expected that at weak to intermediate coupling, d-wave superconductivity can be induced by antiferromagnetic fluctuations. However, one needs to clarify the role of Fermi surface topology, density of states, pseudogap, and wave vector of the magnetic fluctuations on the nature and strength of the induced d-wave state. To this end, we study the generalized phase diagram of the two-dimensio...

A Trypanosoma cruzi expression vector has been constructed using sequences derived from the flanking regions of the glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) genes. The neomycin phosphotransferase (neor) gene was incorporated as a selectable marker. Using electroporation we have introduced this vector into both T. cruzi and Leishmania cells and conferred G418 resistance. Transformation ...

An order bounded disjointness preserving operator T on an Archimedean vector lattice is algebraic if and only if the restriction of Tn! to the vector sublattice generated by the range of Tm is strongly diagonal, where n is the degree of the minimal polynomial of T and m is its ‘valuation’.

The present communication describes the construction of a new Escherichia coli-Treponema denticola shuttle vector based on the naturally occurring spirochete plasmid pTS1 and the expression of the heterologous T. pallidum flaA gene from the plasmid in T. denticola. This new shuttle vector system should prove useful in characterizing virulence factors from unculturable pathogenic spirochetes.