4,369 research outputs found

    A multiobjective approach using consistent rate curves to the calibration of a Gaussian Heath-Jarrow-Morton model

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    In this paper we propose an alternate calibration algorithm, by using a consistent family of yield curves, that fits a Gaussian Heath-Jarrow-Morton model jointly to the implied volatilities of caps and zero-coupon bond prices. The algorithm is capable for finding several Pareto optimal points as is expected for a general nonlinear multicriteria optimization problem. The calibration approach is evaluated in terms of in-sample data fitting as well as stability of parameter estimates. Furthermore, the efficiency is tested against a non-consistent traditional method by using simulated and US market data.HJM models, consistent forward rate curves, multiobjective calibration

    Applications of Intuitionistic Logic in Answer Set Programming

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    We present some applications of intermediate logics in the field of Answer Set Programming (ASP). A brief, but comprehensive introduction to the answer set semantics, intuitionistic and other intermediate logics is given. Some equivalence notions and their applications are discussed. Some results on intermediate logics are shown, and applied later to prove properties of answer sets. A characterization of answer sets for logic programs with nested expressions is provided in terms of intuitionistic provability, generalizing a recent result given by Pearce. It is known that the answer set semantics for logic programs with nested expressions may select non-minimal models. Minimal models can be very important in some applications, therefore we studied them; in particular we obtain a characterization, in terms of intuitionistic logic, of answer sets which are also minimal models. We show that the logic G3 characterizes the notion of strong equivalence between programs under the semantic induced by these models. Finally we discuss possible applications and consequences of our results. They clearly state interesting links between ASP and intermediate logics, which might bring research in these two areas together.Comment: 30 pages, Under consideration for publication in Theory and Practice of Logic Programmin

    Karst flow system information from shape analysis and numerical modeling of tracer concentration curves

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    Dye tracing constitute a very valuable tool for investigating the origin of groundwater and delineating flowpaths in karst media, providing direct and quantitative information about the hydraulic properties and solute transport dynamic within a conduit (and/or fracture) dominated system. In this sense, data obtained from 8 single- and multi-injection tracer experiments performed during last years in different carbonate aquifers located in Malaga province (southern Spain) have been re-examined following the numerical solutions provided by a dual process-based approach: advection–dispersion model (ADM) and two-region non-equilibrium model (2RNE). Tracer tests were conducted under different hydrological conditions (high-intermediate-low flow) affecting the aquifers, and the fluorescent substances were injected into sinkholes (5), losing streams (4), karrenfields (1) and dolines (1), while springs commonly served as detection points (manual sampling and eventually field fluorimeters). Flow and transport parameters estimates obtained from the simulation of 13 tracer breakthrough curves (BTCs) provided mixed information on a wide range of hydrogeological behaviors: from well-developed conduit flow paths to flow and storage modalities in a fissured-like systems. The statistical treatment of the analytical and numerical results, jointly to the field observations, has been especially useful for the characterization of the predominant solute transport processes in the studied experimental sites, given the significant deviations that have been eventually found between the shape of the measured and modeled curves (marked skewness, single/multi-pulse geometry, long-tailing effect, etc). These findings will allow for a better understanding of the structure and dynamic of the karst systems investigated and will may help to protect and preserve karst water resources in the region.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    On the value of water quality observations for karst model parameterization

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    If properly applied, karst hydrological models are a valuable tool for karst water resources management. If they are able to reproduce the relevant flow and storage processes of a karst system, they can be used for prediction of water resources availability when climate or land use are expected to change. A common challenge to apply karst simulation models is the limited availability of observations to identify their model parameters. In this study, we quantify the value of information added to parameter estimation when water quality data (NO3 and SO4) is used in addition to discharge observations to estimate the parameters of a process-based karst simulation model at a test site in Southern Spain. We use a three-step procedure (1) to confine an initial sample of 500,000 model parameter sets, (2) to identify alterations of individual model parameters through the confinement, and (3) to quantify the strength of the confinement for each of the model parameters. The last step allows us to quantify the information content of hydrodynamic and water quality observations for model parameter estimation. Our results show that NO3 provides most information to identify the model parameters controlling soil and epikarst dynamics, while discharge observations provide most information about the recharge area and the groundwater dynamics. SO4 mostly contributes to the identification of recharge processes. Looking at different flow states of the system, we also find that information provided by our observations varies over time.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Reseñas

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    Guillermo OLAGÜE de ROS ; Jorge MOLERO MESA ; Alfredo MENÉNDEZ NAVARRO ; Mikel ASTRAIN GALLART ; Esther ROSADO CAMACHO ; José VALENZUELA CANDELARIO, Catálogo de la biblioteca histórica del Hospital San Juan de Dios de Granad

    Danzas de Otsagi. Notas de tipo general

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    Las danzas de palos no se practican por toda Europa con la misma intensidad. Hay cientos de variantes y que se sepa, no ha habido un intento serio de codificaciĂłn. Las danzas de Otsagi tienen lugar en honor de la Virgen de Muskilda y se realizan los dĂ­as 7 y 8 de setiembre. Se describen las danzas que se bailan ambos dĂ­a

    Technical Note TN 2.2 Fuel load sampling of a Cupressus sempervirens hedge

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    In this document, data from a destructive sampling of a Cupressus sempervirens hedgerow are shown, as well as the followed methodology. Measures of sizes and weights have been taken. With these data, moisture content, fuel load and bulk density have been calculated. Different fuel classes (state and diameter) have been taken into account.Postprint (updated version

    Coupling hydro-geo-chemical and isotopic approaches to assess the main factors controlling karst development in a fissure-dominated carbonate aquifer system (s-Spain)

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    Sierra Tejeda, Almijara and Albuñuelas mountains comprise a large outcrop (750 km² ca) of Triassic marbles in between of Málaga and Granada provinces in S Spain. They constitute a large entity carbonate aquifer system providing strategic groundwater resources for drinking water supply in sparse urban settlements and crops irrigation. The present research aims to refine the current hydrogeological knowledge of large-scale fissure-dominated carbonate aquifers regarding flow mechanisms and geochemical processes defining observed groundwater quality. To this, a two-year monitoring program of aquifer dynamics have been conducted in three selected discharge points (Fájara, Cijancos and Maro springs) showing characteristic spring responses. A combined approach based on the analysis of spring discharge and time series of selected hydrochemical and isotopic tracers (Na+, Ca+2, Mg+2, TA, TOC, Cl-, SO4-2 and δ13CTDIC) and on the geochemical calculations from the chemical signature of spring waters have been followed. The results indicate that the more bicarbonate enriched waters and the lowest hydrochemical variability of Cijancos spring, practically in all analyzed solutes, denotes a fissure type dominant flow system, while the larger variations in meteoric/soil tracers (Cl- and TOC) observed in Fajara spring chemograph as consequence of rainfall inputs characterize a karst drainage from a better hierarchized fracture-enlarged flow system. Maro spring waters are rich in Na+, Ca+2, Cl- and SO4-2, have higher δ13CTDIC amplitude and the temporal variations of major ions display marked dilutions after rainfall events followed by rapid recoveries of pre-event concentrations, evidence a complex flow system and variable groundwater source contribution. The chemical reactions deduced from the molar ratios of spring water chemistry are commonly CO2 dissolution and calcite dissolution, but also salt evapoconcentration in soil layer and gypsum dissolution in the case of Maro spring.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Spatial spillovers in public expenditure on a municipal level in Spain

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    A key function of local governments is to provide a wide array of public services. The supply of these services has been found to create spatial spillovers among neighbouring municipalities. Although it is generally agreed that spillovers are present in models that explain government expenditures, their type—whether endogenous, exogenous or residual—and sign—whether positive or negative—remain ambiguous. In most cases, a subjective process is used to select the type of spatial regression model used in analysis, with mixed results. Per capita expenditures of ten subprogrammes (Security, Housing, Welfare, Environment, Social services, Employment promotion, Health, Education, Culture and Sport) are analysed for all Spanish municipalities with more than 5000 inhabitants in the 2010–2012 period. A Spatial Seemingly Unrelated Regression methodology in a panel framework is used to incorporate correlation between different subprogrammes and spatial dependence. Our results show that the three types of spatial effects are present. Furthermore, substantive dependence is positive in most cases, while negative residual dependence is observed in some.We gratefully acknowledge the contribution of three anonymous reviewers in helping us improve the quality of this paper. Prof. Fernando A. López , grateful for the financial support offered by the projects from Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, Fundación Seneca (#19884-GERM-15) and Ministry of Economy and Competiveness (ECO2015-651758)
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