The role of the terms of trade in the trade channel of transmission of oil price shocks

This paper highlights the role of the terms of trade in the trade channel of propagation of oil price shocks both empirically and theoretically. Empirically, I show that oil price shocks have a large, persistent and statistically significant impact on the US terms of trade. Theoretically, I add oil in the model by Corsetti and Pesenti (2005) and analyse under what conditions the terms of trade plays a relevant role in the international transmission of oil price shocks. With nominal price rigidities and full exchange rate pass-through positive oil price shocks depreciate the currency of the oil importing country. The subsequent negative wealth effect adds to the recessive effect of the supply channel and may trongly reduce the consumption in the oil importing country economy. Without exchange rate pass-through oil shocks transmit to the economy only through the supply channel. The model suggests that a change in the exchange rate pass-through might contribute to explain the evidence of a weaker impact of oil price shocks on the macroeconomic activity in recent times.

Mechanisms implied in Escherichia coli removal during wastewater treatment

Poster presentado 12th Symposium on Aquatic Microbial Ecology (SAME12) August 28 – September 02, 2011 Germany , Rostock–Warnemünde

Fate of Escherichia coli during an activated sludge wastewater treatment

Poster presentado al . 3rd Congress of European Microbiologist (FEMS 2009)celebrado en Gothenburg, Suecia del 28 de junio al 2 de julio de 2009

Dealing with Energy-QoE Trade-Offs in Mobile Video

Scalable video coding allows an efficient provision of video services at different quality levels with different energy demands. According to the specific type of service and network scenario, end users and/or operators may decide to choose among different energy versus quality combinations. In order to deal with the resulting trade-off, in this paper we analyze the number of video layers that are worth to be received taking into account the energy constraints. A single-objective optimization is proposed based on dynamically selecting the number of layers, which is able to minimize the energy consumption with the constraint of a minimal quality threshold to be reached. However, this approach cannot reflect the fact that the same increment of energy consumption may result in different increments of visual quality. Thus, a multiobjective optimization is proposed and a utility function is defined in order to weight the energy consumption and the visual quality criteria. Finally, since the optimization solving mechanism is computationally expensive to be implemented in mobile devices, a heuristic algorithm is proposed. This way, significant energy consumption reduction will be achieved while keeping reasonable quality levels.

Effects of international trade of food and feed and human diet shifts on food security and environmental safety: integrating scales

4 p.

A dynamic CGE modelling approach for analyzing trade-offs in climate change policy options: the case of Green Climate Fund

38 p.

Mechanisms involved in Escherichia coli and Serratia marcescens removal during activated sludge wastewater treatment

Wastewater treatment reduces environmental contamination by removing gross solids and mitigating the effects of pollution. Treatment also reduces the number of indicator organisms and pathogens. In this work, the fates of two coliform bacteria, Escherichia coli and Serratia marcescens, were analyzed in an activated sludge process to determine the main mechanisms involved in the reduction of pathogenic microorganisms during wastewater treatment. These bacteria, modified to express green fluorescent protein, were inoculated in an activated sludge unit and in batch systems containing wastewater. The results suggested that, among the different biological factors implied in bacterial removal, bacterivorous protozoa play a key role. Moreover, a representative number of bacteria persisted in the system as free-living or embedded cells, but their distribution into liquid or solid fractions varied depending on the bacterium tested, questioning the real value of bacterial indicators for the control of wastewater treatment process. Additionally, viable but nonculturable cells constituted an important part of the bacterial population adhered to solid fractions, what can be derived from the competition relationships with native bacteria, present in high densities in this environment. These facts, taken together, emphasize the need for reliable quantitative and qualitative analysis tools for the evaluation of pathogenic microbial composition in sludge, which could represent an undefined risk to public health and ecosystem functions when considering its recycling.