The structural flexibility at three substitution sites in LaFeAsO enabled investigation of the relation between superconductivity and parameters over a wide range crystal compositions. Substitutions Nd for La, Sb or P As, F H O were performed. All these substitutions modify local parameters, while F/H-substitution also changes band filling. It was found that superconducting transition temperatu...

This paper concerns itself with the categorical semantics of -calculi extended with explicit substitutions. For the simply-typed -calculus, indexed categories seem to provide the right categorical framework but because these structures are inherently non-linear, alternate models are needed for linear -calculi extended with explicit substitutions. We propose to replace indexed categories by pres...

Given a finite set S of unimodular Pisot substitutions, we provide a method for characterizing the infinite sequences over S that allow to generate a full discrete plane when, starting from a finite seed, we iterate the multidimensional dual substitutions associated with S. We apply our results to study the substitutions associated with the Brun multidimensional continued fraction algorithm.

Fluorapatite, Ca10(PO4)6F2. is a widely spread form of calcium phosphate present particularly in biological material. Human hard tissues contain crystals structurally related to apatite. Fluoride can be found in various natural sources and is also used for its beneficial action in caries prevention. Fluorapatite belongs to the spatial group P6(3/m) (C(6h)2) and consists of 3 ions: F-, Ca2+, PO4...

It is known on the one hand that a Sturmian sequence can be generated geometrically by the intersections of a straight line with the unit grid in the plane, and on the other hand that fixed points of invertible substitutions are Sturmian. We give a new characterization of invertible substitutions, which allows to determine the straight line which generates the fixed point of a given invertible ...

machines and sharing.Our presentation of a explicit substitution cal-culus has been driven by the correspondence withthe semantics. Of the calculi discussed above, theoriginal -calculus of Abadi et al. [1] is the onlyone with a closer correspondence to a categoricalsemantics. We see our calculus as a direct improve-ment of theirs. Moreover, in earlier work [14] Ritte...

In this tutorial we present the system SUBSEXPL that is used for simulating and comparing explicit substitutions calculi. This framework was developed in Ocaml, a language of the ML family, and it allows the manipulation of expressions of the λ-calculus and of several styles of explicit substitutions calculi. Applications of this framework include: the visualisation of the contractions of the λ...

Recent efforts to estimate the index of dispersion [R(t)] of molecular evolution-i.e., the ratio of the variance in the number of substitutions on a lineage to the mean number-have suffered from an inability to adjust the data for lineage effects. These effects may include the generation-time dependency of the rate of evolution or improper assumptions about the branching pattern of a phylogenet...

background: tubulin protein being the fundamental unit of microtubules is actively involved in cell division thus making them a potential anti-cancer drug target. in spite of many reported drugs against tubulin, few of them have started developing resistance in human β-tubulin due to amino acid substitutions. methods: in this study we generated three mutants (f270v, a364t and q292e) using model...