Report on the Standardization Project ``Formal Methods in Conformance Testing''

This paper presents the latest developments in the “Formal Methods in Conformance Testing” (FMCT) project of ISO and ITU–T. The project has been initiated to study the role of formal description techniques in the conformance testing process. The goal is to develop a standard that defines the meaning of conformance in the context of formal description techniques. We give an account of the current status of FMCT in the standardization process as well as an overview of the technical status of the proposed standard. Moreover, we indicate some of its strong and weak points, and we give some directions for future work on FMCT

Internal frequency conversion extreme ultraviolet interferometer using mutual coherence properties of two high-order-harmonic sources

International audienceWe report on an innovative two-dimensional imaging extreme ultraviolet (XUV) interferometer operating at 32 nm based on the mutual coherence of two laser high order harmonics (HOH) sources, separately generated in gas. We give the first evidence that the two mutually coherent HOH sources can be produced in two independent spatially separated gas jets, allowing for probing centimeter-sized objects. A magnification factor of 10 leads to a micron resolution associated with a subpicosecond temporal resolution. Single shot interferograms with a fringe visibility better than 30% are routinely produced. As a test of the XUV interferometer, we measure a maximum electronic density of 3×10^20 cm^−3 1.1 ns after the creation of a plasma on aluminum target

Pension fund performance and costs: small is beautiful.

Abstract Using the CEM pension fund data set, we document the cost structure and performance of a large sample of US pension funds. To date, self-reporting biases and a deficiency of comprehensive return and cost data have severely hindered pension fund performance studies. The bias-free CEM dataset resolves these issues and provides detailed information on fund-specific returns, benchmarks and costs for all types of pension plans and equity mandates. We find that pension fund cost levels are substantially lower than mutual fund fees. The domestic equity investments of US pension funds tend to generate abnormal returns (after expenses and trading costs) close to zero or slightly positive, contrasting the average underperformance of mutual funds. However, small cap mandates of defined benefit funds have outperformed their benchmarks by about 3% a year. While larger scale brings costs advantages, liquidity limitations seem to allow only smaller funds, and especially small cap mandates, to outperform their benchmarks. JEL Classifications : G23, G11, G14 Acknowledgements Our thanks to Keith Ambachtsheer, CEM Benchmarking Inc. for providing the pension fun

SILICA AEROGELS PREPARED BY HYPERCRITICAL ACETONE EVACUATION

Le tétraméthoxysilane est le précurseur utilisé. La réaction d'hydrolyse, effectuée en milieu acétone, conduit à des gels monolithiques dans un grand domaine de compositions. Le séchage hypercritique est directement réalisé sur les gels tels qu'ils ont été obtenus. Les conditions permettant d'élaborer des aérogels monolithiques sont précisées. L'analyse structurale des aérogels montre qu'ils sont similaires à ceux obtenus dans des conditions d'évacuation hypercritique de solvants alcooliques. Cependant, la distribution des groupements hydroxyles est fortement affectée par la nature du solvant employé. L'évolution de la structure des aérogels en fonction de la température est étudiée. Le frittage s'effectue à des températures supérieures à 1000°C et l'aérogel se transforme en verre.Tetramethoxysilane is used as the silica source. The hydrolysis reaction, carried out in acetone, leads to gels which are monolithic in a large domain of compositions. The hypercritical drying is directly performed on the gels as obtained. Conditions to prepare monolithic aerogels are reported. The structural analysis of the aerogels shows that they are similar to those obtained from hypercritical drying in alcoholic medium. However, the hydroxyl group distribution is strongly affected by the nature of the solvent. The evolution of the structure of the aerogels as a function of temperature is investigated. Sintering occurs above 1000°C and the aerogel transforms into glass