High-resolution infrared and theoretical study of gaseous 1,2,5-selenadiazole in the 600-1400 cm range

The Fourier transform gas-phase IR spectrum of natural isotopic 1,2,5-selenadiazole, C₂H₂N₂Se, has been recorded with a resolution of ca. 0.0025 cm⁻¹ in the wavenumber region 600-1400 cm⁻¹. The three a-type bands, ν₂ (A₁), ν₄ (A₁), ν₅ (A₁), the two b-type bands ν₁₁ (B₁), ν₁₂ (B₁), and the c-type band ν₁₄ (B₂) for each of the isotopologues C₂H₂N₂⁸⁰Se and C₂H₂N₂⁷⁸Se have been analyzed using the Watson model. Ground state rotational and quartic centrifugal distortion constants as well as upper state spectroscopic constants have been obtained from the fits. The rotational constants, harmonic and anharmonic frequencies, and vibration-rotation constants (alphas, ) have been predicted by quantum chemical calculations using a cc-pVTZ basis at the MP2 and B3LYP methodology levels, and compared with the present experimental data. Although the rotation constants are marginally closer to experiment from the MP2 calculations, in general the B3LYP frequencies and alphas are closer to experiment.     

An application of cooperative game among container terminals of one port

In this paper a two-stage game that involves three container terminals located in Karachi Port in Pakistan is discussed. In the first stage, the three terminals have to decide on whether to act as a singleton or to enter into a coalition with one or both of the other terminals. The decision at this stage should presumably be based on the predicted outcome for the second stage. The second stage is here modelled as a Bertrand game with one outside competitor, the coalition and the terminal in Karachi Port (if any) that has not joined the coalition. Furthermore, three partial and one grand coalition among the three terminals at Karachi Port are investigated. The concepts of “characteristic function” and “core” are used to analyse the stability of these coalitions and this revealed that one combination does not satisfy the superadditivity property of the characteristic function and can therefore be ruled out. The resulting payoffs (profits) of these coalitions are analysed on the basis of “core”. The best payoff for all players is in the case of a “grand coalition”. However, the real winner is the outsider (the terminal at the second port) which earns a better payoff without joining the coalition, and hence will play the role of the “orthogonal free-rider”.     

Projections of quantum observables onto classical degrees of freedom in mixed quantum-classical simulations: understanding linear response failure for the photoexcited hydrated electron

We present a general analytic method for understanding how specific motions of a classical bath influence the dynamics of quantum-mechanical observables in mixed quantum-classical molecular dynamics simulations. We apply our method and develop expressions for the special case of quantum solvation, allowing us to examine how specific classical solvent motions couple to the equilibrium energy fluctuations and nonequilibrium energy relaxation of a quantum-mechanical solute. As a first application of our formalism, we investigate the motions of classical water underlying the equilibrium and nonequilibrium excited-state solvent response functions of the hydrated electron; the results allow us to explain why the linear response approximation fails for this system.     

E center in silicon has a donor level in the band gap

It has been an accepted fact for more than 40 years that the E center in Si (the group-V impurity--vacancy pair)--one of the most studied defects in semiconductors--has only one energy level in the band gap: namely, the acceptor level at about 0.45 eV below the conduction band. We now demonstrate that it has a second level, situated in the lower half of the band gap at 0.27 eV above the valence band. The existence of this level, having a donor character, is disclosed by a combination of different transient-capacitance techniques and electronic-structure calculations. The finding seriously questions some diffusion-modeling approaches performed in the past.     

Permutohedral spaces and the Cox ring of the moduli space of stable pointed rational curves

We study the Cox ring of the moduli space of stable pointed rational curves, ${\overline{M}_{0,n}}$ , via the closely related permutohedral (or Losev-Manin) spaces ${\overline{L}_{n-2}}$ . Our main result establishes $\left(\begin{array}{ll} n \\ 2 \end{array}\right)$ polynomial subrings of ${{\rm Cox}(\overline{M}_{0,n})}$ , thus giving collections of boundary variables that intersect the ideal of relations of ${{\rm Cox}(\overline{M}_{0,n})}$ trivially. As applications, we give a combinatorial way to partially solve the Riemann-Roch problem for ${\overline{M}_{0,n}}$ , and we show that all relations in degrees of ${{\rm Cox}(\overline{M}_{0,6})}$ arising from certain pull-backs from projective spaces are generated by the Plücker relations.     

Equivalent dose distribution analysis of Holocene eolian and fluvial quartz sands from Central Oklahoma

Holocene quartz sands were collected from fluvial terrace deposits and eolian dune deposits adjacent to the North Canadian and Cimarron Rivers and their tributaries in Central Oklahoma. Single aliquot regenerative dose optically stimulated luminescence techniques were employed to generate equivalent dose (ED) distribution histograms for each sample. We hypothesize that the ED distributions are convolutions of the distribution arising from natural sedimentary processes, influenced primarily by the degree of solar resetting experienced by individual grains, and a distribution due to experimental error. An estimation of the experimental error distribution for each sample was made and this was then deconvolved from the experimentally measured ED distribution to reveal the ‘sedimentary process’ ED distribution. Objective methods for determining EDs, uncertainties, and confidence parameters from the deconvolved distributions are presented.     

Kinetic analysis of dynamic point defect pinning in aluminium initiated by strain rate changes

The role of point defect production during deformation was examined by sealing the vacancy sinks in the grain boundaries with solutes to magnify its effect upon instantaneous strain-rate changes. AA1100 aluminium sheets were thermal-mechanically treated to result in a grain size of about 25 µm and in grain boundaries that were not capable of acting as efficient vacancy sinks. Tensile tests at various temperatures ranging from 78 to 300 K showed that above 195 K, the pinning effect could be quantitatively analysed. A rate equation analysis for mono- and di-vacancy recovery was adopted to perform fits to the deduced change in flow stress with time after strain-rate change from which apparent activation energies were derived. This examination indicates that the migrating species are predominantly di-vacancies. It is concluded that point-defect atmospheres have the capacity to glide in unison with mobile dislocations and hence are sensitive to the magnitude of the strain rate and temperature.     

Designing and scaling up an innovation in abstract algebra

In this paper, we describe the process of designing and scaling up the TAAFU group theory curriculum. This work unfolded in three overlapping stages of research and design. The initial designs emerged along with local instructional theories as the result of small-scale design experiments conducted with pairs of students. A second stage of the research and design process focused on generalizing from the initial laboratory design context to an authentic classroom setting. The third (ongoing) stage involves generalizing to instructors (mathematicians) who were not involved in the design process. We describe each of these stages, and our efforts to investigate the efficacy of the resulting curriculum, in order to provide an illustrative example of the process of scaling up an innovation.     

No Arbitrage and the Growth Optimal Portfolio

Abstract

Recently, several papers have expressed an interest in applying the Growth Optimal Portfolio (GOP) for pricing derivatives. We show that the existence of a GOP is equivalent to the existence of a strictly positive martingale density. Our approach circumvents two assumptions usually set forth in the literature: 1) infinite expected growth rates are permitted and 2) the market does not need to admit an equivalent martingale measure. In particular, our approach shows that models featuring credit constrained arbitrage may still allow a GOP to exist because this type of arbitrage can be removed by a change of numéraire. However, if the GOP exists the market admits an equivalent martingale measure under some numéraire and hence derivatives can be priced. The structure of martingale densities is used to provide a new characterization of the GOP which emphasizes the relation to other methods of pricing in incomplete markets. The case where GOP denominated asset prices are strict supermartingales is analyzed in the case of pure jump driven uncertainty.     

The development of improved syntheses of PPARγ-sparing,insulin sensitizing thiazolidinedione-ketones

Ketones 2 (MSDC-0160) and 3 (MSDC-0602) had been selected for clinical development, however their initial syntheses were considered suboptimal for application deep into clinical trials. Difficulties ranging from the nature of the starting material, alcohol oxidation problems, epoxide opening regioisomeric issues, and endgame ketone redox problems had been encountered. Direct ketone introduction/maintenance was desired for maximum efficiency and convergence was found to be critically dependent upon the acidity of the nucleophilic species (13, 18) and the use of pre- or post-alkylative oximino-ether/oxime protection (vide infra). Improvements in overall yield for the syntheses of 2 (MSDC-0160) and 3 (MSDC-0602) from 20% (2) and 31% (3) respectively, to 44% (2) and 59% (3) were realized.