Within the effective-field theory with correlations (EFT), a transverse random field spin-1 Ising model on the simple cubic (z=6) lattice is studied. The phase diagrams, the behavior of critical points, transverse magnetization,  internal energy, magnetic specific heat are obtained numerically and discussed for different values of p the concentration of the random transverse field.

The distribution of the allophones of /?/in certain contexts involves free variation and gradient preferences. An organized survey was conducted to elicit the judgments of 37 native Persian speakers concerning the well-formedness of /?/allophonic behavior in five different phonological positions. The results showed that the differences in judgment between the various categories are not just t...

BACKGROUND Tashiromine 1 is a naturally occurring indolizidine alkaloid. It has been the subject of thirteen successful total syntheses to date. Our own approach centres on the stereoselective construction of the indolizidine core by capture of an electrophilic acyliminium species by a pendant allylsilane. The key cyclisation precursor is constructed using olefin cross-metathesis chemistry, whi...

The decomposition of a Z-selective ruthenium metathesis catalyst and structurally similar analogues has been investigated utilizing X-ray crystallography and density functional theory. Isolated X-ray crystal structures suggest that recently reported C-H activated catalysts undergo decomposition via insertion of the alkylidene moiety into the chelating ruthenium-carbon bond followed by hydride e...

Cross-metathesis of α- and β-vinyl C-deoxyribosides and α-vinyl C-galactoside with various terminal alkenes under different conditions was studied. The cross-metathesis of the former proceeded with good yields of the corresponding products in ClCH2CH2Cl the latter required the presence of CuI in CH2Cl2 to achieve good yields of the products. A simple method for the preparation of α- and β-vinyl...

The Z-selective ethenolysis activity of chelated ruthenium metathesis catalysts was investigated with experiment and theory. A five-membered chelated catalyst that was successfully employed in Z-selective cross metathesis reactions has now been found to be highly active for Z-selective ethenolysis at low ethylene pressures, while tolerating a wide variety of functional groups. This phenomenon a...

Adapting arguments from Eisner (1997, 2000), this remark provides a simple proof that the generation problem for Optimality Theory (OT, Prince and Smolensky 2004) is NP-hard. The proof needs only the binary evaluation of constraints and uses only constraints generally employed in the OT literature. In contrast, rule-based derivational systems are easily computable, belonging to the class of pol...

In this article we show how Optimality Theory yields a highly general Constraint Demotion principle for grammar learning. The resulting learning procedure specifically exploits the grammatical structure of Optimality Theory, independent of the content of substantive constraints defining any given grammatical module. We decompose the learning problem and present formal results for a central subp...

GENERATIVE PHONOLOGY [q.v.] aims to construct a predictive theory of natural language sound systems, rooted in a finely-detailed account of the principles defining linguistic representations and the possible relations between them. Within these broad goals, OPTIMALITY THEORY (OT) develops in the context of specific empirical theses about the way phonological systems are organized. We identify t...