K?ln-Timi?oara Molecular Activity Combined Models toward Interspecies Toxicity Assessment

Aiming to provide a unified picture of computed activity – quantitative structure activity relationships, the so called Köln (ESIP-ElementSpecificInfluenceParameter) model for activity and Timisoara (Spectral-SAR) formulation of QSAR were pooled in order to assess the toxicity modeling and inter-toxicity correlation maps for aquatic organisms against paradigmatic organic compounds. The Köln ESIP model for estimation of a compound toxicity is based on the experimental measurement expressing the direct action of chemicals on the organism Hydractinia echinata so that the structural influence parameters are reflected by the metamorphosis degree itself. As such, the calculation of the structural parameters is absolutely necessary for correct evaluation and interpretation of the evolution of M(easured) and the C(computed) values. On the other hand, the Timişoara Spectral-SAR analysis offers correlation models and paths for H.e. species as well as for four other different organisms with which the toxicity may be inter-changed by means of the same mechanism of action induced by certain common chemicals.     

Nucleophile Substitutionen an funktionellen Kohlensäurederivaten. XVI. Kinetik und Mechanismus der Hydrolyse von Kohlensäure- N,N,N′-triphenylchloramidin

Nucleophilic Substitution to Carbonic Acid Derivatives. XVI. Kinetics and Mechanism of N,N,N′-Triphenylchloroformamidin Hydrolysis First order rate constants of N,N,N′-triphenylchloroformic amidine hydrolysis in dioxane-water have been determined by u.v.-spectroscopy. The effects of water concentration, addition of KClO₄, LiCl, HgCl₂, and AgNO₃ or nucleophilic agents (piperidine) as well as isotopic effects have been investigated. Activation entropy and enthalpy have been determined. According to the data obtained the reaction takes place in two steps – chlorionization and reaction of the formed cation with the nucleophilic agent. Both steps have rates of the same order of magnitude, but can become slow steps in specific conditions.     

Including cultural water requirements in environmental flow assessment: an example from the upper Ganga River,India

The rituals of riparian communities are frequently linked to the flow regimes of their river. These dependencies need to be identified, quantified and communicated to policy makers who manage river flows. This paper describes the first attempt to explicitly evaluate the flows required to maintain the cultural and spiritual activities in the upper Ganga River basin. Riparian dwellers and visitors were interviewed and the responses analyzed to obtain an overview of the needs and motivations for cultural flows. The approach enhances the overall concept of environmental flow assessment, especially in river basins where spiritual values ascribed to rivers are high.