Regional analysis of parameter sensitivity for simulation of streamflow and hydrological fingerprints

Diagnostics of hydrological models are pivotal for a better understanding of catchment functioning, and the analysis of dominating model parameters plays a key role for region-specific calibration or parameter transfer. A major challenge in the analysis of parameter sensitivity is the assessment of both temporal and spatial differences of parameter influences on simulated streamflow response. We present a methodological approach for global sensitivity analysis of hydrological models. The multilevel approach is geared towards complementary forms of streamflow response targets, and combines sensitivity analysis directed to hydrological fingerprints, i.e. temporally independent and temporally aggregated characteristics of streamflow (INDPAS), with the conventional analysis of the temporal dynamics of parameter sensitivity (TEDPAS).The approach was tested in 14 mesoscale headwater catchments of the Ruhr River in western Germany using simulations with the spatially distributed hydrological model mHM. The multilevel analysis with diverse response characteristics allowed us to pinpoint parameter sensitivity patterns much more clearly as compared to using TEDPAS alone. It was not only possible to identify two dominating parameters, for soil moisture dynamics and evapotranspiration, but we could also disentangle the role of these and other parameters with reference to different streamflow characteristics. The combination of TEDPAS and INDPAS further allowed us to detect regional differences in parameter sensitivity and in simulated hydrological functioning, despite the rather small differences in the hydroclimatic and topographic setting of the Ruhr headwaters

A unified approach to exposure assessment by computer models for degradation reactions and soil accumulation : the triazine herbicide example.

A comprehensive approach to exposure assessment of chemicals must include metabolites of the initial compounds. We present here an approach that combines a knowledge-based system for the prediction of degradation pathways with an analytical soil transport model. The performance of this combination of systems is illustrated with an analysis of seven s-triazine herbicides and their 35 degradation products. In a ranking procedure using the Hasse diagram technique, the relationships between chemical structure and the hazard potential in a loam soil scenario is analyzed. Sequences of chemical structures with comparable and non-comparable hazard potentials are identified

Generic properties of chemical networks: Artificial chemistry based on graph rewriting

We use a Toy Model of chemistry that represents molecules in terms of usual structural formulae to generate large chemical reaction networks. An extremely simplified quantum mechanical energy calculation and a straightforward implementation of reactions as graph rewritings ensure both transparency and closeness to chemical reality, both conditions that are necessary for the analysis of generic properties of large reaction networks. We show that some chemical networks graphs, e.g., repetitive Diels-Alder reactions, have the small-world property and exhibit a scale-free degree distribution. On the other hand, the Formose reaction does not fit well to this paradigm

A fotomontagem como função política Photomontage as a political function

O movimento dadá em Berlim distingue-se por um projeto de intervenção política, em sintonia com a orientação ideológica de vários de seus integrantes. Entre estes pode ser destacado John Heartfield, interessado, desde 1915, em desenvolver uma linguagem ao mesmo tempo moderna e acessível a um público de massa. Para tanto, lança mão da fotografia nas capas executadas para a editora Malik e é responsável pelo desenvolvimento da fotomontagem política, que divulga sobretudo numa revista do Partido Comunista Alemão, o Arbeiter Illustrierte Zeitung.<br>The main feature of Berlin Dada is a project of political intervention, attuned to the ideological orientation of many of its members. Among them we can distinguish John Heartfield, who since 1915 looks for a language both modern and accessible to a mass audience. Therefore Heartfield makes use of photography in the bookcovers for Malik Verlag and is responsible for the development of political photomontage, published mainly in a magazine of the German Communist Party, Arbeiter Illustrierte Zeitung