The MODERE Model and The Economic Analysis of Farmers’ Decisions

The MODERE, the Ministry of the Environment Irrigation Decision Model, is a simulation tool which uses mathematical programming methods to reveal the implicit multiattribute objective function lying behind the observed cropping decision. The model takes different criteria such as profit maximization, risk aversion, avoidance of management complexities and so forth into account. In order to determine the feasible combination of attributes of this objective function the model considers the production possibility frontier explicitly as depending on market prices, policy incentives, availability of production factors, water irrigation facilities agronomic vocation and other constraints. Once calibrated the model becomes a powerful tool to assess the impact of different policy scenarios such as subsidies decoupling, water prices modifications, irrigation technique substitution and so on. The MODERE is a preference revelation model purposedly designed to be integrated in the Decision Support Platform which is used by the Spanish Ministry of the Environment to compare the policy scenarios which are relevant to assess the effectiveness and economic impact of the measures designed to reach the environmental objectives of the Water Framework Directive. The model is supported by a comprehensive data base built on purpose for its implementation covering almost all the Spanish Irrigation Districts with high spatial detail. This model is currently one of the important modules of the information and decision support systems developed by the Economic Analysis Unit of the Water Directorate at the Ministry of the Environment in Spain.Agricultural Economics, Water Economics, Simulated Models, Land Economics/Use, Political Economy, Research Methods/ Statistical Methods, Resource /Energy Economics and Policy,

Enhancing Irrigation Efficiency but Increasing Water Use: The Jevons' Paradox

In this paper we analyze the conditions under which increasing technical efficiency of water use in the agricultural sector might not reduce water demand and pressures on water ecosystems. Departing from this basic problem we discuss how policy measures performed to enhance water productivity in the agriculture might be transformed into effective alternatives to improve the conservation of water resources and then guarantee the successful implementation of the Water Framework Directive. A preference revelation model is presented in the third section of the paper and one empirical application to an irrigation district in southern Spain is used in the fourth section to discuss the effectiveness of water savings measures.Water Framework Directive, Water Economics, Agricultural Economics, Simulation Models, Preference Revelation., Resource /Energy Economics and Policy,

The closed-string 3-loop amplitude and S-duality

The low-energy limit of the four-point 3-loop amplitude (including its overall coefficient) is computed in both type IIA and IIB superstring theories using the pure spinor formalism. The result is shown to agree with the prediction of the coefficient for the type IIB $D^6 R^4$ interaction made by Green and Vanhove based on S-duality considerations.Comment: 26 pages, harvmac. v3: factor of 3 in section 3.3 corrected, updated abstract and dropped Z_3-symmetry argumen

A note on the existence of non-monotone non-oscillating wavefronts

In this note, we present a monostable delayed reaction-diffusion equation with the unimodal birth function which admits only non-monotone wavefronts. Moreover, these fronts are either eventually monotone (in particular, such is the minimal wave) or slowly oscillating. Hence, for the Mackey-Glass type diffusive equations, we answer affirmatively the question about the existence of non-monotone non-oscillating wavefronts. As it was recently established by Hasik {\it et al.} and Ducrot {\it et al.}, the same question has a negative answer for the KPP-Fisher equation with a single delay.Comment: 11 pages, 3 figures, submitte

Economic regional impacts of water transfers: the role of factor mobility in a case study of the agricultural sector in the Balearic Islands

Using a CGE model for the Balearic Islands, we simulate the effects of an agricultural water market in the farming sector facing reductions in the water endowment. The market lessens the negative effects on farming communities of short-term water restrictions associated with cyclical droughts. However, in scenarios of permanent reductions, such as those envisaged by global warming predictions or those that result from the implementation of the European Water Framework Directive, a water market may aggravate the negative effects of water shortage. Therefore, the paper shows that generalizations cannot be made about the effects of water markets on farming communities.Agricultural and Food Policy, Environmental Economics and Policy, D58, Q1, Q25, R13,

Ultrasonic, molecular and mechanical testing diagnostics in natural fibre reinforced, polymer-stabilised earth blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties