Dynamics of a salinity-prone agricultural catchment driven by markets, farmers' attitude and climate change

An agent-based simulation model has been developed with CORMAS combining simplified bio-physical processes of land cover, dry-land salinity changes, rainfall, farm profitability and farmer decisions on land uses in a dry-land agricultural catchment (no irrigation). Simulated farmers formulate individual decisions dealing with land use changes based on the combined performance of their past land cover productivity and market returns. The willingness to adapt to market drivers and the ability to maximize returns varies across farmers. In addition, farmers in the model can demonstrate various attitudes towards salinity mitigation as a consequence of experiencing and perceiving salinity on their farm, in the neighborhood or in the entire region. Consequently, farmers can adopt land cover strategies aiming at reducing salinity impact. The simulation results using historical rainfall records reproduces similar trends of crop-pasture ratios, salinity change and farm decline as observed in the last 20 years in the Katanning catchment (Western Australia). Using the model as an explorative tool for future scenarios, the simulation results highlighted the importance of rainfall changes and wide-spread willingness of farmers to combat dry-land salinity. Rainfall changes as a consequence of climate change can lead to prolonged sequences of dry and wet seasons. Adaptation to these sequences by farmers seems to be critical for farm survival in this catchment. (Résumé d'auteur

Indigo in the nanochannels of zeolite L : towards a new type of colorant

A host-guest based colorant was synthesized by intercalating indigo molecules into the nanochannels of zeolite L (ZL). Reductive washing thereby ensured the efficient and selective removal of non-intercalated indigo molecules. The UV-vis diffuse reflectance spectrum of the product after intercalation and reductive washing (designated as indigo-ZL) was found to resemble the solution spectrum of indigo, leading to the conclusion that the formation of indigo aggregates is prevented due to the steric constraints imposed by the microporous structure of ZL. The application of indigo-ZL on cotton was tested by roll coating. The light absorption properties of the resulting textile prints showed no significant alteration when compared to the pure indigo-ZL powder. The UV-vis diffuse reflectance spectra of mixtures consisting of indigo-ZL and a further ZL-based colorant were successfully predicted by the weighted addition of the respective primary spectra

Advances in N-15-tracing experiments: new labelling and data analysis approaches

To obtain an in-depth understanding of soil nitrogen dynamics, it is necessary to quantify a variety of simultaneously occurring gross nitrogen transformation processes. In order to do so, most studies apply N-15 in a disturbed soil-microbial-root system and quantify gross rates based on the principles of N-15 isotope dilution. However, this approach has several shortcomings. First, studying disturbed soil provides only limited information on in situ soil nitrogen dynamics. Secondly, the analytical data analysis allows the quantification of total production and consumption rates of the labelled pool, but does not provide information on process-specific transformation rates. Combining in situ N-15 isotope labelling over 1-2 weeks with numerical data analysis allows determining process-specific gross nitrogen transformations in undisturbed soils under field conditions in the presence of live roots and their associated microbial communities. This has the potential to increase our understanding of nitrogen dynamics in the soil environment

Initial performance metrics of a new custom-designed ArF excimer LA-ICPMS system coupled to a two-volume laser-ablation cell

We measure the performance improvement that force feedback can provide in a virtual environment, through three experiments with, and without the assistance of haptic guidance. Performance measurements were undertaken with haptic, visual and auditory feedback alternatives. The first task investigated the use of haptic guidance mimicking reality, in the form of a simulated touchable surface of an object. The second investigated haptic guidance which waxed and waned as the user violated program rules by varying amounts. The third experiment investigated whether this latter artificial guidance would inhibit the user's free will by taking control out of their hands. The results showed that a significant improvement in both accuracy and speed was achieved by the introduction of haptics in all experiments. It also found that the haptic guidance did not take control away from the user and that they had significantly more control than with conventional warning methods. These experiments were not aimed at learning, or retention of skill, but on using haptics as an aid to improve performance during a task. Due to the rapidly increasing software content in embedded systems, Hardware-dependent Software (HdS) has become a critical topic in system design. In this paper, we provide a brief overview on the topic of HdS, discuss the issues and complexities involved in the design of HdS, and motivate the need for special attention to HdS in research and development. A new custom-built excimer (193 nm) laser-ablation system with two-volume laser-ablation cell coupled to a quadrupole ICPMS is described, which combines rapid ( 10000 cps/ppm for mid-high m/z, 55 mu m, 5 Hz). An application of reconstructing medieval Pb exposure highlights the need for rapid signal washout in unravelling strongly varying Pb peaks in well-preserved archaeological tooth enamel