Dense stellar matter in asymptotically free gauge theories: I. The high density limit

In asymptotically free gauge theories perturbation theory may be used to obtain the behavior of dense stellar matter. The criteria for the determination of ?_crit, the minimum density above which perturbation theory is valid, are presented. The asymptotic form for the quark-gluon thermodynamic potential is given.     

Elementary extensions of models of set theory

Model Theoretic methods are used to extend models of set theory while leaving specified sets fixed. In particular, every countable modelU of ZF has: (i) an extension leaving every set inU fixed, and (ii) for each (inU) regular cardinala an extension enlarginga but leaving each cardinal less thana fixed. Some of out results were announced in the abstract [8]. Our research was supported in part by NSF contracts 4297 and 5913. The first named author is an Alfred E. Sloan Foundation Fellow.     

Decidable models

A modelU is decidable if Th(U,a) _a∈A is recursive. Various results about decidable models are discussed. A necessary and sufficient condition for there to be a decidable saturated model is given. Dedicated to the memory of Abraham Robinson     

Bridge Cleavage Reactions of Dinuclear Diselenolenes: Preparation of Palladium Complexes of Novel Chelating Selenolato/Selenide Ligands, [PdX(Se{R′}CnH2n−4Se)(PR3)](n = 6, 7, 8; R = Ph,Bu; X = Br,I; R′ = Me,Et, etc.)

Abstract

The dinuclear palladium diselenolenes [Pd₂(Se₂C_nH_2n?4)₂(PR₃)₂] react with haloalkanes, via electrophilic attack at the bridging selenium atoms, to yield the neutral mononuclear square planar palladium(II) complexes [PdX(Se{R′}C_nH_2n?4Se)(PR₃)] (n = 6, 7, 8; R = Ph, Bu; X = Br, I; R′ = Me, Et, etc.), containing a novel chelating selenolato/selenide ligand, in which the alkylated selenium and halogen donor atoms occupy cis-positions. The products have been characterised by mass spectrometry and multinuclear NMR spectroscopy; the molecular structure of the compound with n = 8, R = Ph, R′ = Et has been determined by X-ray crystallography.     

Spatial field shifts in ocean acoustic environmental sensitivity analysis

This article examines the effects of spatial field shifts in ocean acoustic environmental sensitivity analysis. Acoustic sensitivity studies are typically based on comparing acoustic fields computed for a reference environmental model and for a perturbed model in which one or more parameters have been changed. The perturbation to the acoustic field due to the perturbed environment generally includes a component representing a spatial shift of the field (i.e., local field structure remains coherent, but shifts in range and/or depth) and a component representing a change to the shifted field. Standard sensitivity measures based on acoustic perturbations at a fixed point can indicate high sensitivity in cases where the field structure changes very little, but is simply shifted by a small spatial offset; this can conflict with an intuitive understanding of sensitivity. This article defines and compares fixed-point and field-shift corrected sensitivity measures. The approaches are illustrated with examples of deterministic sensitivity (i.e., sensitivity to a specific environmental change) and stochastic sensitivity (sensitivity to environmental uncertainty) in range-independent and range-dependent environments.     

Synthesis and characterization of Pd and Pt complexes of 1,3-bis(ferrocenylchalcogeno)propanes: crystal structures of FcSe(CH2)3SeFc and [M{FcE(CH2)3E'Fc}2](PF6)2 (M = Pd, Pt; E, E' = Se, Te; Fc = [Fe(eta5-C5H5)(eta5-C5H4)])

Reaction of a 1,3-bis(ferrocenylchalcogeno)propane, FcE(CH2)3E'Fc (L: E, E' = Se or Te; Fc = [Fe(eta5-C5H5)(eta5-C5H4)]), with a palladium(II) or platinum(II) precursor [M(NCMe)4](PF6)2 (M = Pd or Pt) in acetonitrile at room temperature led in good yield to the bis-chelate complexes [ML2](PF6)2. The structures of FcSe(CH2)3SeFc and all six complexes have been determined by X-ray crystallography. Electrochemical studies showed that electronic communication between ferrocenyl groups, absent in all three bis(ferrocenylchalcogeno)propanes, is established on complexation only for E = Se and E' = Se or Te, when the through-bond Fe...Fe distance is reduced to 13.17 A or less.