The Covariant W_3 Action

Starting from SL(3,R) Chern-Simons theory we derive the covariant action for W_3 gravity.Comment: 14 page

KPZ Analysis for W3W_3 Gravity

Starting from the covariant action for $W_3$ gravity, we discuss the BRST quantization of $W_3$ gravity. Taking the chiral gauge the BRST charge has a natural interpretation in terms of the quantum Drinfeld--Sokolov reduction for Sl(3,\re). Nilpotency of this charge leads to the KPZ formula for $W_3$. In the conformal gauge, where the covariant action reduces to a Toda action, the BRST charge is equivalent to the one recently constructed by Bershadsky et al.Comment: 26 pages, THU-92/3

A 2:1 cocrystal of 6,13-dihydropentacene and pentacene

6,13-Dihydropentacene and pentacene cocrystallize in a ratio of 2:1, i.e. C22H16·0.5C22H14, during vapour transport of commercial pentacene in a gas flow. The crystal structure is monoclinic, space group P21/n, and contains one dihydropentacene molecule and half a pentacene molecule in the asymmetric unit.

The Stockholm Convention:A Tool for the Global Regulation of Persistent Organic Pollutants

The aim of the Stockholm Convention on Persistent Organic Pollutants (POPs) is to eliminate persistent organic chemicals worldwide by either prohibiting their production and use or gradually reducing them. The Stockholm Convention was adopted in 2001 and entered into force in 2004, 90 days after receiving the 50th instrument of ratification. The Parties to the Convention have to regularly report progress in implementation of their measures taken to achieve the goals. The Convention has a mechanism to add more compounds; today 28 POPs are covered, 16 more than the initial ones

Hazardous compounds in recreational and urban recycled surfaces made from crumb rubber. Compliance with current regulation and future perspectives

Crumb rubber obtained from scrap tires is greatly employed for the construction of different facilities for sport, recreational and other uses. However, in recent years the concern about their safety and the related adult and children exposure to these surfaces is growing. This study aims a thorough chemical characterization encompassing 42 hazardous compounds, including polycyclic aromatic hydrocarbons (PAHs), phthalates, adipates, antioxidants and vulcanization agents in a wide range of crumb rubber from different surfaces. For the extraction of the target compounds, a method based on ultrasound-assisted extraction followed by gas chromatography-tandem mass spectrometry (UAE-GC–MS/MS) has been validated. Forty crumb rubber samples coming from synthetic turf football pitches, outdoor and indoor playgrounds, urban pavements, commercial tiles and granulates, and scrap tires, were analyzed. In addition, green alternative materials, such as sand and artificial turf based on cork granulate infill were included to compare the levels of the target compounds with those of crumb rubber. Most of the analyzed recycled surfaces meet the recent limits proposed by the European Commission for rubber granulates and mulches, although they exceed in several cases the maximum levels allowed for rubber consumer products. Besides, most of the other target compounds, including several of them considered as endocrine disruptors, were detected in the analyzed samples, reaching parts per million concentrations

The unified coordination language UnCL.

In this paper we show how to use a (subset) of UML as an Unified Coordination Language (UnCL) that is based on a separation of concerns between coordination and computation. As such UnCL provides a general language for the coordination of, in particular, object-oriented applications. The basic idea of UnCL is to use UML as a formalism to specify the `glue code' in terms of state-machines which are added to the classes of the underlying applications. These state-machines describe the coordination of the objects of the underlying applications in terms of sending and receiving events. We introduce a formal semantics of UnCL and discuss its implementation using a new tool for the transformation of XML data which is based on a new Rule Markup Language (RML). Finally, we discuss the incorporation of a more high-level coordination mechanism called MoCha, an exogenous coordination framework for (distributed) communication and collaboration using mobile channels as its mediu

Maatschappelijk vastgoed:aanhouden of verkopen

In dit onderzoeksrapport staat het maatschappelijk vastgoed van de gemeente Emmen centraal. De gemeente Emmen staat voor de keuze of zij haar maatschappelijk vastgoed moet gaan verkopen of niet. Dit onderzoek is uitgevoerd via een indirecte opdrachtgever. Deze indirecte opdrachtgever is een aanspreekpunt voor de gemeente Emmen en voor het onderzoeksteam. In het onderzoek wordt voor de gemeente Emmen onderzocht welke mogelijke manieren er zijn om haar maatschappelijk vastgoed te verkopen, waarbij zij haar invloed behoud. De centrale vraag zal volledig beantwoord worden door alle informatie die door kwalitatieve methoden verzameld is. Het doel van het onderzoek is, een passende manier voor de gemeente Emmen vinden om haar maatschappelijk vastgoed te verkopen met behoudt van invloedsmogelijkheden. De probleemstelling van het onderzoek is als volgt samengesteld: “Welke mogelijkheden heeft de gemeente Emmen tot haar beschikking, om ervoor te zorgen dat na verkoop van haar maatschappelijk vastgoed, haar invloed deels behouden kan blijven?”. Studentonderzoek in het kader van het thema Leefomgeving