435 research outputs found

    Multi-Criteria Analysis of Factors Use Level: The Case of Water for Irrigation

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    In this paper we present a methodology to analyse input use in the agricultural sector. The novelty of the theoretical model explained is that it has been developed considering a multi-criteria environment. Thus, the optimal input use condition is determined by the assessment of “multi-attribute utility” and “multiattribute marginal utility”. We show how the approach adopted in this paper is a generalization of the single-attribute expected utility theory. The theoretical model developed is further implemented in an empirical application that studies water for irrigation use as a particular case. Results show how multi-attribute utility functions elicited for a sample of 52 irrigators explain differences on irrigation water use in relative homogenous agricultural systems, albeit exhibiting similar water partial utility functions. We conclude that these differences come from the dissimilar weights that farmers attached to each attribute in the aggregate utility function. The irrigated area considered as case study is located in North-western Spain.Production Theory, Input Use, MAUT, Water for Irrigation, Spain

    Power Estimation Technique for DSP Architectures.

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    The main goal of power estimation is to optimize the power consumption of a electronic design. Power is a strongly pattern dependent function. Input statistics greatly influence on average power. We solve the pattern dependence problem for intellectual property (IP) designs. In this paper, we present a power macro-modeling technique for digital signal processing (DSP) architectures in terms of the statistical knowledge of their primary inputs. During the power estimation procedure, the sequence of an input stream is generated by a genetic algorithm using input metrics. Then, a Monte Carlo zero delay simulation is performed and a power dissipation macro-model function is built from power dissipation results. From then on, this macro-model function can be used to estimate power dissipation of the system just by using the statistics of the macro-block’s primary in puts. In experiments with the DSP system, the average error is 26%

    Water Markets in Spain: Performance and Challenges

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    Law 46/1999 incorporated formal water markets into the Spanish legal and regulatory framework, allowing spot water markets and the creation of water banks. The implementation of water markets in Spain aimed at improving the efficiency of water use by reallocating water towards uses with higher added value. However, the performance of water markets in Spain has been rather disappointing, since they have been operative only during drought periods, and even under these extreme scarcity situations, trading activity counted for less than 5.0% of total water use. The narrowness of the market suggests that there are some barriers hampering their effective functioning. This paper examines the evolution and performance of water markets in Spain, relying on a transaction costs analysis framework. This analysis allows the identification of the main factors impeding water markets from operating effectively as a water reallocation tool. This analysis also provides some guidelines on how to overcome these obstacles and, thus, how to improve the efficiency of water use

    Modeling at farm level: Positive Multi-Attribute Utility Programming

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    This article proposes a new mathematical programming model for the simulation of farmers’ decision-making. We have developed a model based on a multi-attribute utility approach that takes into consideration the most relevant attributes of farmers within a positive framework. This approach overcomes the limitations found in some mathematical models used in the literature to simulate farmers’ behavior. A five-step procedure is presented in order to elicit the utility function that reproduces farmers’ current decision-making. We illustrate this positive multi-attribute approach using a sample of farmers in an irrigated area in southern Spain, where our simulations demonstrate the accurateness of the model in reproducing actual farmers’ decision-making. We also find evidence that the model is able to explain the heterogeneous behavior of farmers within a homogeneous agricultural syste

    ECG, an essential tool to guide arrhythmic mitral valve prolapse diagnosis

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    A 35-year-old man was referred for cardiac check-up because of suspected reflex syncope. He underwent a tilt-test challenge without syncope provocation. The electrocardiography (ECG) showed sinus rhythm with polymorphic premature ventricular contractions (PVC), with right bundle branch block morpholog

    Morpho-kinematic analysis of the point-symmetric, bipolar planetary nebulae Hb 5 and K 3-17, a pathway to poly-polarity

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    The kinematics of the bipolar planetary nebulae Hb~5 and K 3-17 are investigated in detail by means of a comprehensive set of spatially resolved high spectral resolution, long-slit spectra. Both objects share particularly interesting characteristics, such as a complex filamentary, rosette-type nucleus, axial point-symmetry and very fast bipolar outflows. The kinematic information of Hb~5 is combined with {\it HST} imagery to construct a detailed 3D model of the nebula using the code SHAPE. The model shows that the large scale lobes are growing in a non-homologous way. The filamentary loops in the core are proven to actually be secondary lobes emerging from what appears to be a randomly punctured, dense, gaseous core and the material that forms the point symmetric structure flows within the lobes with a distinct kinematic pattern and its interaction with the lobes has had a shaping effect on them. Hb~5 and K~3-17 may represent a class of fast evolving planetary nebulae that will develop poly-polar characteristics once the nebular core evolves and expands.Comment: 19 pages, 8 figures. To appear in The Astrophysical Journa

    Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean

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    0000-0002-7993-1523© 2015 Riesgo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    Evolutionary origins of sensation in metazoans: functional evidence for a new sensory organ in sponges

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    Background: One of the hallmarks of multicellular organisms is the ability of their cells to trigger responses to the environment in a coordinated manner. In recent years primary cilia have been shown to be present as 'antennae' on almost all animal cells, and are involved in cell-to-cell signaling in development and tissue homeostasis; how this sophisticated sensory system arose has been little-studied and its evolution is key to understanding how sensation arose in the Animal Kingdom. Sponges (Porifera), one of the earliest evolving phyla, lack conventional muscles and nerves and yet sense and respond to changes in their fluid environment. Here we demonstrate the presence of non-motile cilia in sponges and studied their role as flow sensors. Results: Demosponges excrete wastes from their body with a stereotypic series of whole-body contractions using a structure called the osculum to regulate the water-flow through the body. In this study we show that short cilia line the inner epithelium of the sponge osculum. Ultrastructure of the cilia shows an absence of a central pair of microtubules and high speed imaging shows they are non-motile, suggesting they are not involved in generating flow. In other animals non-motile, 'primary', cilia are involved in sensation. Here we show that molecules known to block cationic ion channels in primary cilia and which inhibit sensory function in other organisms reduce or eliminate sponge contractions. Removal of the cilia using chloral hydrate, or removal of the whole osculum, also stops the contractions; in all instances the effect is reversible, suggesting that the cilia are involved in sensation. An analysis of sponge transcriptomes shows the presence of several transient receptor potential (TRP) channels including PKD channels known to be involved in sensing changes in flow in other animals. Together these data suggest that cilia in sponge oscula are involved in flow sensation and coordination of simple behaviour. Conclusions: This is the first evidence of arrays of non-motile cilia in sponge oscula. Our findings provide support for the hypothesis that the cilia are sensory, and if true, the osculum may be considered a sensory organ that is used to coordinate whole animal responses in sponges. Arrays of primary cilia like these could represent the first step in the evolution of sensory and coordination systems in metazoans. © 2014 Ludeman et al.; licensee BioMed Central Ltd
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