Phytotoxicity,cytotoxicity, and in vivo antifungal efficacy of chitosan nanobiocomposites on prokaryotic and eukaryotic cells

Environmental Science and Pollution Research - Chitosan (CS) nanosystems have potential applications for the control of microorganisms in the medical, environmental, and agrifood fields. In vivo...     

A note on permits, standards, and technological innovation

Montero (J. Environ. Econom. Manage. 44 (2002) 23) contrasts the incentives to invest in new abatement technologies under different regulatory instruments and argues that one needs to consider the induced output effects that derive from lower abatement costs. Montero shows that, once one takes into account these effects on output, command-and-control instruments can generate stronger incentives to innovate than market-based instruments. This result rests on strategic output effects under command-and-control. However, he maintains that, under perfectly competitive conditions, market-based instruments will continue to weakly dominate command-and-control regulation. This note clarifies two issues raised by Montero. First, I use Montero's approach to show that in fact performance (concentration) standards will generate greater incentives to innovate than market-based instruments in perfectly competitive markets. One does not require strategic effects to get this result. Second, Montero abstracts from production costs and concentrates solely on abatement costs. He implicitly assumes that marginal production costs are constant. I show that some of Montero's results change once increasing marginal production costs are considered. When marginal costs are increasing, the benefit of additional output is tempered and market-based instruments again look more favorable.     

100 years running: The need to understand why employee physical activity benefits organizations

Employee physical activity initiatives are commonplace, but management scholarship has not kept pace with theoretical and empirical work to validate such initiatives. In this Incubator, we clarify the employee physical activity construct, present mechanisms linking physical activity to organizationally valued outcomes, and consider the dark side of employee physical activity initiatives. Copyright © 2015 John Wiley & Sons, Ltd.     

Streamflow,Sediment Transport,and Geomorphic Change during the 2011 Flood on the Missouri River Near Bismarck–Mandan,ND

Geomorphic change from extreme events in large managed rivers has implications for river management. A steady‐state, quasi‐three‐dimensional hydrodynamic model was applied to a 29‐km reach of the Missouri River using 2011 flood data. Model results for an extreme flow (500‐year recurrence interval [RI]) and an elevated managed flow (75‐year RI) were used to assess sediment mobility through examination of the spatial distribution of boundary or bed shear stress (τ_b) and longitudinal patterns of average τ_b, velocity, and kurtosis of τ_b. Kurtosis of τ_b was used as an indicator of planform channel complexity and can be applied to other river systems. From differences in longitudinal patterns of sediment mobility for the two flows we can infer: (1) under extreme flow, the channel behaves as a single‐thread channel controlled primarily by flow, which enhances the meander pattern; (2) under elevated managed flows, the channel behaves as multithread channel controlled by the interaction of flow with bed and channel topography, resulting in a more complex channel; and (3) for both flows, the model reach lacks a consistent pattern of deposition or erosion, which indicates migration of areas of erosion and deposition within the reach. Despite caveats and limitations, the analysis provides useful information about geomorphic change under extreme flow and potential implications for river management. Although a 500‐year RI is rare, extreme hydrologic events such as this are predicted to increase in frequency.     

Comparison of Measured and MM5 Modeled Meteorology Data for Simulating Flow in a Mountain Watershed1

Herr, Joel W., Krish Vijayaraghavan, and Eladio Knipping, 2010. Comparison of Measured and MM5 Modeled Meteorology Data for Simulating Flow in a Mountain Watershed. Journal of the American Water Resources Association (JAWRA) 46(6):1255–1263. DOI: 10.1111/j.1752-1688.2010.00489.x Abstract: Accurate simulation of time-varying flow in a river system depends on the quality of meteorology inputs. The density of meteorology measurement stations can be insufficient to capture spatial heterogeneity of precipitation, especially in mountainous areas. The Watershed Analysis Risk Management Framework (WARMF) model was applied to the Catawba River watershed of North and South Carolina to simulate flow and water quality in rivers and a series of 11 reservoirs. WARMF was linked with the AMSTERDAM air model to analyze the water quality benefit from reduced atmospheric emissions. The linkage requires accurate simulation of meteorology for all seasons and for all types of precipitation events. WARMF was driven by the mesoscale meteorology model MM5 processed by the Meteorology Chemistry Interface Processor, which provides greater spatial density but less accuracy than meteorology stations. WARMF was also run with measured data from the National Climatic Data Center (NCDC) to compare the performance of the watershed model using measured data vs. modeled meteorology as input. A one year simulation using MM5 modeled meteorology performed better overall than the simulation using NCDC data for the volumetric water balance measure used for calibration, but MM5 represented precipitation from a dissipated hurricane poorly, which propagated into errors of simulated flow.     

Anaerobic co-digestion of fat,oil, and grease (FOG): A review of gas production and process limitations

The addition of readily available high strength organic wastes such as fats, oils, and grease (FOG) from restaurant grease abatement devices may substantially increase biogas production from anaerobic digesters at wastewater treatment facilities. This FOG addition may provide greater economic incentives for the use of excess biogas to generate electricity, thermal, or mechanical energy. Co-digestion of FOG with municipal biosolids at a rate of 10–30% FOG by volume of total digester feed caused a 30–80% increase in digester gas production in two full scale wastewater biosolids anaerobic digesters (Bailey, 2007, Muller et al., 2010). Laboratory and pilot scale anaerobic digesters have shown even larger increases in gas production. However, anaerobic digestion of high lipid wastes has been reported to cause inhibition of acetoclastic and methanogenic bacteria, substrate, and product transport limitation, sludge flotation, digester foaming, blockages of pipes and pumps, and clogging of gas collection and handling systems. This paper reviews the scientific literature on biogas production, inhibition, and optimal reactor configurations, and will highlight future research needed to improve the gas production and overall efficiency of anaerobic co-digestion of FOG with biosolids from municipal wastewater treatment.