Let S = Sg,n be a connected, orientable surface of genus g ≥ 0 with n ≥ 0 punctures. Let Teich(S) denote the corresponding Teichmüller space, and let Mod(S) denote the mapping class group of S. Understanding the analogy of Teich(S) with symmetric spaces is a wellknown theme. Recall that a complete Riemannian manifold X is symmetric if it is symmetric at each point x ∈ X: the map γ(t) 7→ γ(−t) w...

We describe the geometry of geodesics on a Lorentz ellipsoid: give explicit formulas for the first integrals (pseudo-confocal coordinates), curvature, geodesically equivalent Riemannian metric, the invariant area-forms on the timeand space-like geodesics and invariant 1-form on the space of null geodesics. We prove a Poncelet-type theorem for null geodesics on the ellipsoid: if such a geodesic ...

Density functional theory calculations have been employed to investigate the mechanism of gold(I)-catalysed rearrangements of cyclopropenes. Product formation is controlled by the initial ring-opening step which results in the formation of a gold-stabilised carbocation/gold carbene intermediate. With 3-phenylcyclopropene-3-methylcarboxylate, the preferred intermediate allows cyclisation via nuc...

A facile synthesis of highly functionalized 2H-iminopyran derivatives by the multi-component reaction of cyclohexyl isocyanide, dialkyl acetylenedicarboxylates, arylglyoxals and arylamines is described. The zwitterionic intermediate produced by addition of cyclohexyl isocyanide to electron-deficient acetylene diesters was trapped by the electrophilic imine moiety of α-iminoketones, derived from...

We introduce a family of extremal polynomials associated with the prolongation of a stratified nilpotent Lie algebra. These polynomials are related to a new algebraic characterization of abnormal subriemannian geodesics in stratified nilpotent Lie groups. They satisfy a set of remarkable structure relations that are used to integrate the adjoint equations.

a two-year laboratory study on the biology (including self-fertilization) of bulinus truncatus, the intermediate host of schistosoma haematobium, s. bovis and paramphistomum microbotrium in iran, has revealed information on the longevity, reproduction, hatchability rate, hatching time during various months of the year, and growth and mortality rates of this snail. it was found that the reproduc...

Problem statement: The problem is to classify a given web query to a set of 67 target categories. The target categories are ranked based on the degree of similarity to a given query. Approach: The feature set is the set of intermediate categories retrieved from a directory search engine for a given query. Using direct mapping and Normalized Web Distance (NWD) the intermediate categories are map...

An efficient stereoselective synthesis of a pivotal intermediate, cyclic allyl alcohol derivative containing two methoxy groups [(±)-22], using for the preparation (±)-trans-dihydronarciclasine analogues was elaborated starting from easily available and inexpensive methyl gallate. This new synthetic route consists 17 reaction steps, provides an opportunity to obtain wanted alkaloid additional g...

In this paper we present Scalable Position-Based Multicast (SPBM), a multicast routing protocol for ad-hoc networks. SPBM uses the geographic position of nodes to provide a highly scalable group membership scheme and to forward data packets with a very low overhead. SPBM bases its multicast forwarding decision on whether there are group members located in a given direction or not, allowing for ...