Weyl group multiple Dirichlet series constructed from quadratic characters

We construct multiple Dirichlet series in several complex variables whose coefficients involve quadratic residue symbols. The series are shown to have an analytic continuation and satisfy a certain group of functional equations. These are the first examples of an infinite collection of unstable Weyl group multiple Dirichlet series in greater than two variables having the properties predicted in [2].     

Treasury Management Model with Foreign Exchange Exposure

In this paper we formulate a model for foreign exchange exposure management and (international) cash management taking into consideration random fluctuations of exchange rates. A vector error correction model (VECM) is used to predict the random behaviour of the forward as well as spot rates connecting dollar and sterling. A two-stage stochastic programming (TWOSP) decision model is formulated using these random parameter values. This model computes currency hedging strategies, which provide rolling decisions of how much forward contracts should be bought and how much should be liquidated.The model decisions are investigated through ex post simulation and backtesting in which value at risk (VaR) for alternative decisions are computed. The investigation (a) shows that there is a considerable improvement to “spot only” strategy, (b) provides insight into how these decisions are made and (c) also validates the performance of this model.     

Measurement and analysis of excitation functions for alpha-induced reactions in copper

Excitation functions for the production of⁶⁸Ga,⁶⁷Ga,⁶⁶Ga,⁶⁵Ga +⁶⁵Zn and⁶¹Cu fromα-induced reactions in natural copper have been measured in the energy range ≈ 10–40 MeV using the stacked foil technique. A stack of nine copper foils was irradiated by a 40 MeVα-beam. Theγ-rays emitted from the irradiated samples were recorded. Excitation functions have also been calculated theoretically using a statistical model with and without the inclusion of pre-equilibrium emission of particles. Pre-equilibrium component simulated by exciton model shows that the inclusion of pre-equilibrium emission gives better agreement between experimental and theoretical excitation functions. Pre-equilibrium fraction depends on the incident energy and the target mass number.     

Synthesis of new fluorinated 4H-1,4-benzothiazines as possible anticancer agents

A single-step synthesis for ring-fluorinated 4H-1,4-benzothiazines is reported by the condensation and oxidative cyclization of β-diketones with 2-amino-5-fluorobenzenethiol. The reaction is believed to proceed via an enaminoketone system.     

Electrical properties of a-antimony selenide

This paper reports conduction mechanism in a-Sb₂Se₃ over a wide range of temperature (238 to 338 K) and frequency (5 Hz to 100 kHz). The d.c. conductivity measured as a function of temperature shows semiconducting behaviour with activation energy ΔE=0.42 eV. Thermally induced changes in the electrical and dielectric properties of a-Sb₂Se₃ have been examined. The a.c. conductivity in the material has been explained using modified CBH model. The band conduction and single polaron hopping is dominant above room temperature. However, in the lower temperature range the bipolaron hopping dominates.     

Synthesis of 6-halogenated 4H-1,4-benzothiazines

The synthesis of 6-halogenated 4H-1,4-benzothiazines is reported by the condensation and oxidative cyclization of 4-substituted 2-aminobenzenethiols (I, R = Cl, Br) with β-diketones in presence of DMSO. The ir, nmr and mass spectral studies are included. 4-Substituted 2-aminobenzenethiols were also prepared by an improved and direct method.     

Permion spectrum in a confined SU(n) quark model

An explicit form of a colour-singlet Fermion field is constructed from the operator solution of SU(n) Thirring model where the quark-fields are known to be confined in LSZ sense. In simple cases of massless quarks these ferions are free with zero mass and can be expressed as the antisymmetric composites of constituent quark fields. This simple exercise suggests an alternative to conventional two-dimensional QCD which seems to confine all Fermion including baryons by Schwinger mechanism.