36 research outputs found

    Ground-penetrating radar observations of enhanced biological activity in a sandbox reactor

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    In this study, we evaluate the use of ground-penetrating radar (GPR) to investigate the effects of bacterial activity in water saturated sand. A 90-day laboratory-scale controlled experiment was conducted in a flow-through polycarbonate sandbox using groundwater from the Kansas River alluvial aquifer as inoculum. After 40 days of collecting baseline data, bacterial growth was stimulated in the sandbox by the addition of a carbon and nutrient solution on a weekly basis. Radar signal travel time and attenuation were shown to increase downgradient of the nutrient release wells relative to upgradient locations. After 60 days, the frequency of nutrient injections was increased to twice per week, after which gaseous bubbles were visually observed downgradient of the nutrient release wells. Visual observation of active gas production correlated spatially and temporally with a rapid decrease in radar signal travel time, confirming that GPR can monitor the generation of biogenic gases in this system. Analysis of the sediments indicated microbial lipid biomass increased by approximately one order of magnitude and there were no changes in the inorganic carbon content of bulk sediment mineralogy. These findings suggest that the increase in biomass and gas production may be responsible for the observed changes in radar signal travel time reported in this study. Therefore, this study provides evidence that GPR can be used to monitor biological activity in water saturated sand.Funding for this project was through the National Science Foundation CAREER grant 0134545 awarded to J.F. Devlin and NSF EAR/IF-0345445 for acquisition of GPR instrumentation awarded to G. Tsoflias. The opinions, findings, and recommendations of this study are the views the author(s) and do not necessarily reflect the views and opinions of the National Science Foundation. We would like to thank Mike McGlashan, Kwan Yee Cheng, Kelly Peterson, Lindsay Mayer, and Breanna Huff for assistance with this project. We also thank two anonymous reviewers for their helpful comments that led to the improvement of this manuscript

    The Interpretation of European Private Law in the Light of Market Freedoms and EU Fundamental Rights

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    Recent initiatives in the area of European private law seem to rely ever more extensively on very broad, general and vague provisions, in particular the concept of ‘good faith and fair dealing’, a concept already present in the acquis communautaire. These and similarly vague terms will only have an impact if interpreted autonomously and unitarily by a central authority. Despite its cautious approach regarding the assessment of the fairness of contract terms, this task can rest only with the European Court of Justice. This article explores whether and to what extent the four market freedoms regarding the free movement of goods, persons, services and capital, as well as the fundamental rights developed by the Court's jurisprudence, now laid down in the EU Charter on Fundamental Rights, may contribute to the development of an autonomous European method of legal reasoning. </jats:p
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