Micro-computed tomography scanning approaches to quantify,parameterize and visualize bioturbation activity in clogged streambeds: A proof of concept

Fine particle clogging and faunal bioturbation are two key processes co-occurring in the hyporheic zone that potentially affect hyporheic exchange through modifications in the sediment structure of streambeds. Clogging results from excessive fine sediment infiltration and deposition in rivers, and it is known to decrease matrix porosity and potentially reduce permeability. Faunal bioturbation activity may compensate for the negative effect of clogging by reworking the sediment, increasing porosity, and preventing further infiltration of fines. Although both processes of clogging and bioturbation have received significant attention in the literature separately, their combined effects on streambed sediment structure are not well understood, mostly due to the lack of a standard methodology for their assessment. Here, we illustrate a novel methodology using X-ray computed tomography (CT), as proof of concept, to investigate how, together, clogging and bioturbation affect streambed porosity in a controlled flow-through flume. By visualising gallery formations of an upward conveyor macroinvertebrate; Lumbriculus variegatus as a model species, we quantified bioturbation activity in a clogged streambed, focusing on orientation, depth, and volume at downwelling and upwelling areas of the flume. Gallery creation increased the porosity of the streambed sediment, suggesting a potential improvement in permeability and a possible offset of clogging effects. We illustrate the promising use of X-ray CT as a tool to assess bioturbation in clogged streambeds, and the potential role of bioturbation activity supporting hyporheic exchange processes in streambeds, warranting further studies to understand the extent of bioturbation impacts in natural systems.     

Annual redd counts across two decades are indicators of changing migratory bull trout population sizes in two proximate Montana creeks

Redd counts are the most widely used method for bull trout (Salvelinus confluentus Suckley) population monitoring. Redd counts are an assumed indicator of population size (N), particularly for female spawners, but previous studies rarely considered the measurement uncertainty of N. The present study of two proximate, migratory bull trout populations across two decades examined statistical correlations between annual redd counts and concurrent N (predominantly fish ages 3–7) that included measurement uncertainty. Results showed that redd counts explained about one-third of the concurrent N variation and, in one case, portended N 7 years later. But changing spawning distributions across years, as likewise shown here and as a probable effect of ongoing climate change, can confound the use of fixed index reaches for redd counts. Instead, abundance monitoring based on redd counts should be over a bull trout population's or metapopulation's entire spatial extent and have counts in all potential spawning areas. Such total-annual redd counts may be the most cost-effective and precise means of bull trout population monitoring.     

Equity and efficiency as components of a social welfare function

An income distribution-based abbreviated social welfare function is an increasing function of equity and efficiency. When inequality is of relative type, we characterize variants of the Atkinson–Kolm–Sen and the Shorrocks abbreviated welfare functions, where the variation results from the existence of a corresponding trade-off parameter, and in each case if the parameter becomes one the two forms coincide. When the value of the parameter increases, equity gains more weight in the equity–efficiency trade-off. For absolute inequality, we characterize the Blackorby–Donaldson–Kolm welfare function. Some implications of the lexicographic-type equity used in the paper are also considered.     

(De-)Stabilizing two-country macroeconomic interactions in an estimated model of the U.S. and the Euro Area

In this paper a semi-structural macroeconomic model based on gradually adjusting wages and prices and hybrid, cross-over inflation expectation formation is analyzed and estimated with aggregate data of the U.S. and the Euro Area. Besides comparing, among other things, the determinants of the wage- and price inflation dynamics in both economies, the role of different macroeconomic transmission channels for the stability of the two-country system is investigated.     

Environmental evaluation of agri-environment schemes using participatory approaches: Experiences of testing the Agri-Environmental Footprint Index

The Agri-Environment Footprint Index (AFI) has been developed as a generic methodology to assess changes in the overall environmental impacts from agriculture at the farm level and to assist in the evaluation of European agri-environmental schemes (AES). The methodology is based on multi-criteria analysis (MCA) and involves stakeholder participation to provide a locally customised evaluation based on weighted environmental indicators. The methodology was subjected to a feasibility assessment in a series of case studies across the EU. The AFI approach was able to measure significant differences in environmental status between farms that participated in an AES and non-participants. Wider environmental concerns, beyond the scheme objectives, were also considered in some case studies and the benefits for identification of unintentional (and often beneficial) impacts of AESs are presented. The participatory approach to AES evaluation proved efficient in different environments and administrative contexts. The approach proved to be appropriate for environmental evaluation of complex agri-environment systems and can complement any evaluation conducted under the Common Monitoring and Evaluation Framework. The applicability of the AFI in routine monitoring of AES impacts and in providing feedback to improve policy design is discussed.     

Agricultural commodities pricing model applied to the Brazilian sugar market

This article suggests a pricing model for commodities used to produce biofuel. The model is based on the concept that the deterministic component of the Wiener process is not constant and depends on time and exogenous variables. The model, which incorporates theory of storage, the convenience yield and the seasonality of harvests, was applied in the Brazilian sugar market. After predictions were made with the Kalman filter, the model produced results that were statistically more accurate than those returned by the two‐factor model available in the literature.     

Women rule: potato markets,cellular phones and access to information in the Bolivian highlands

In highland Bolivia, potato markets are widespread and access to market information has entered the digital age. Information networks lubricated by ubiquitous cellular technologies are supplanting traditional means of information‐gathering. We explore the impacts of access to cellular phones on market selection, use of social networks to acquire information, and gendered responsibilities within the potato market chain near Cochabamba. The entire family participates in potato production and marketing, but responsibilities are differentiated by gender. Men take a leading role in potato production and women in marketing. Access to cellular phones affects decisions about where to market potatoes and improves the potato marketing process.     

The in situ physiology of "Nostocoida limicola" II, a filamentous bacterial morphotype in bulking activated sludge, using fluorescence in situ hybridization and microautoradiography.

The in situ physiology of the actinobacterial bulking and foaming filamentous bacterium "Nostocoida limicola" II was studied by fluorescence in situ hybridization/microautoradiography. Substrate assimilation patterns of pure cultures of this bacterium were different to those seen in activated sludge biomass samples. There was no evidence to suggest that "N. limicola" II preferred hydrophobic substrates, but evidence was produced to support the view that it is metabolically active under anaerobic conditions in activated sludge.