Comparative Progressive Metamorphism of Igneous and Sedimentary Rocks

Metamorphic rocks are frequently arranged in zones around igneous intrusions, and each of these zones has certain characteristic minerals by which it can be recognized. Zones of low-grade metamorphism, garnet, kyanite and sillimanite are frequently discernible, and these zones are remarkably similar in different regions, even though the original rocks may have been quite diverse. This similarity in the rocks formed by the metamorphism of igneous and sedimentary rocks suggests that many rocks assumed to be meta-igneous may really be meta-sedimentary in origin

Occurrence of Certain Small Fossil Plates in the Maquoketa Shale of Iowa

Small calcareous plates, possibly from Asteroidea or other Echinodermata, occur in the Maquoketa shale of Iowa. These plates all have similar characteristics, but vary in their minute structures, and the variations apparently have some stratigraphic significance

Work Hard, Play Hard – A Work Ethic Forged in the Group Oppolzer

The author gives an account of his work as post-doc at the University of Geneva in the group of W. Oppolzer, putting emphasis on scientific rigour and ingenuity

Composition mechanisms for retrenchment

Retrenchment is a flexible model evolution formalism that arose as a reaction to the limitations imposed by refinement, and for which the proof obligations feature additional predicates for accommodating design data. Composition mechanisms for retrenchment are studied. Vertical, horizontal, dataflow, parallel and fusion compositions are described. Of particular note are the means by which the additional predicates compose. It is argued that all of the compositions introduced are associative, and that they are mutually coherent. Composition of retrenchment with refinement, so important for the smooth interworking of the two techniques, is discussed. Decomposition, allowing finer grained retrenchments to be extracted from a single large grained retrenchment, is also investigated

A Class of Transformations for Box‐Jenkins Seasonal Models

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/147030/1/rssc00953.pd

Celastraceae sesquiterpene pyridyl ligands

Celastraceae plant extracts have been widely used as traditional medicines and insecticides in China and South America. More recently, the extracts from Celastraceae plants have been studied at the molecular level and many of the interesting medicinal and agrochemical properties can be attributed to a large class of sesquiterpene alkaloids found in these extracts. These are generally based on highly oxygenated dihydroagarofuran cores with pyridyl diacid macrodilactone bridging ligands. Whereas previous reviews have focused on the dihydroagarofuran cores, in this article, the history, structure, and syntheses of the macrodilactone bridging ligands are reviewed

Z2SAL: a translation-based model checker for Z

Despite being widely known and accepted in industry, the Z formal specification language has not so far been well supported by automated verification tools, mostly because of the challenges in handling the abstraction of the language. In this paper we discuss a novel approach to building a model-checker for Z, which involves implementing a translation from Z into SAL, the input language for the Symbolic Analysis Laboratory, a toolset which includes a number of model-checkers and a simulator. The Z2SAL translation deals with a number of important issues, including: mapping unbounded, abstract specifications into bounded, finite models amenable to a BDD-based symbolic checker; converting a non-constructive and piecemeal style of functional specification into a deterministic, automaton-based style of specification; and supporting the rich set-based vocabulary of the Z mathematical toolkit. This paper discusses progress made towards implementing as complete and faithful a translation as possible, while highlighting certain assumptions, respecting certain limitations and making use of available optimisations. The translation is illustrated throughout with examples; and a complete working example is presented, together with performance data

A robust semantics hides fewer errors

In this paper we explore how formal models are interpreted and to what degree meaning is captured in the formal semantics and to what degree it remains in the informal interpretation of the semantics. By applying a robust approach to the definition of refinement and semantics, favoured by the event-based community, to state-based theory we are able to move some aspects from the informal interpretation into the formal semantics