Importance of exposure route for behavioural responses in Lumbriculus variegatus Müller (Oligochaeta: Lumbriculida) in short-term exposures to Pb

Abstract Goal, Scope and Background Lumbriculus variegatus Müller (Oligochaeta), a common freshwater sediment-dweller, has frequently been used in toxicokinetic studies, although has been less used in ecotoxicity tests. Methods For the first time the Multispecies Freshwater Biomonitor® (MFB) was applied in a short-term whole-sediment toxicity test. The MFB automatically and quantitatively recorded the spontaneous locomotory behaviour of Lumbriculus variegatus in exposures with two compartments, water and sediment. The study questioned, whether the animals altered their locomotion depending on the compartment which was spiked with lead (Pb). Results and Discussion As in the exposures to Pb-contaminated water/clean sediment, the animals exposed to Pb-contaminated sediment/clean water showed higher activities in intermediate Pb-concentrations. This indicates, that spontaneous locomotory activity is affected by Pb-concentrations at sublethal levels regardless of whether the Pb-concentration is found in the water or in the sediment, because these animals use both environmental compartments simultaneously. However, within the same Pb-levels, the animals showed higher locomotory activity in contaminated water compared with contaminated sediment. This indicates a possible tendency to withdraw from (‘avoidance’) contaminated water into the clean sediment compartment, whereas there was no withdrawal from contaminated sediment into clean water. The latter might be explained by the fact that withdrawal from sediment to water might increase the risk of predation and drift in nature, whereas retracting to sediment might provide shelter. Conclusions The study showed that spontaneous locomotory responses of L. variegatus to Pb depend on whether the water or sediment is contaminated. The study also concluded that the Multispecies Freshwater Biomonitor® can be applied effectively in sediment toxicity testing. Recommendations and Perspectives More emphasis should be given to the interactions of water/sediment in sediment ecotoxicity tests to better simulate field conditions and increase ecological realism in risk assessment, especially as quantitative recording methods exisit

Propositional, Probabilistic and Evidential Reasoning: Integrating numerical and symbolic approaches

Current software projects have generally to deal with producing and managing large and complex software products. It is generally believed that applying software development methods are useful in coping with this complexity and for supporting quality. As such numerous object-oriented software development methods have been defined. Nevertheless, methods often provide a complexity by their own due to their large number of artifacts, method rules and their complicated processes. We think that automation of software development methods is a valuable support for the software engineer in coping with this complexity and for improving quality. This paper presents a summary and a discussion of the ideas that were raised during the workshop on automating object-oriented software development methods

Collaboration and composition:Issues for a second generation process language

Over the past decade a variety of process languages have been defined and applied to software engineering environments. The idea of using a process language to encode a software process as a "process model", and enacting this using a process-sensitive environment is now well established. Many prototype process-sensitive environments have been developed; but their use in earnest has been limited. We are designing a second generation process language which is a significant departure from current conventional thinking. Firstly a process is viewed as a set of mediated collaborations rather than a set of partially ordered activities. Secondly emphasis is given to how process models are developed, used, and enhanced over a potentially long lifetime. In particular the issue of composing both new and existing model fragments is central to our development approach. This paper outlines these features, and gives the motivations behind them. It also presents a view of process suppor..